NEXRAD: How to Use It Correctly KITPLANES

NEXRAD: How to Use it Correctly KITPLANES

MARCH

2018

® Durand Mark V • NEXRAD • Speed Mods • Homebuilt Accidents • EFII System 32 • Battery Problems • Xenos Spars • T3 Tailwheel • Flanged Composite Parts

BELVOIR Low-Cost Speed Mods MARCH 2018 Fly Faster with Fairings In the Shop: PUBLICATIONS Homebuilt Accidents • Battery Problems Comparing the Rates • Drilling in Tight Places • Building Xenos Spars EFII System 32 Electric Lycoming www.kitplanes.com FROM DYNON AND ADVANCED FLIGHT SYSTEMS

A completely custom panel, Designed for “plug-n-play” with guidance from our experts upgradability

Your choice of Powder Advanced AF-5000 coated and silk series or Dynon screened panel SkyView in your panel

Save hundreds of hours with harnesses customized for your Custom switch modules with aircraft, tied together crisp tactile feel and LED with the exclusive power indication ADVANCED Control Module

You’re a homebuilder, not an electrician. You love crafting your airplane, and can’t wait to fly now that it has wings. A Quick Panel cuts hundreds of hours off your avionics system installation with a complete, professionally engineered panel, delivered ready-to-install in your homebuilt aircraft.

To customize your Quick Panel, call us today at (503) 263-0037 dynon.aero/quickpanels CONTENTSMarch 2018 | Volume 35, Number 3 Flight Review 6 Durand Reinstatement: Planning a kit for the unique Mark V negative-stagger biplane. By Scott M. Spangler. Builder Spotlight 16 neXRAD for Kit Aircraft Drivers: A tremendous safety tool for wise, cautious pilots. By Myron Nelson. 22 effect of Fairings on Speed: Reducing drag is an economical way to go faster. By Nigel Speedy. 26 tricked-Out Tailwheel: T3 suspension system eliminates relaunches when touchdowns are a bit too firm. By Paul Dye. 30 homebuilt Accidents—Comparing the Rates: 16 A true head-to-head comparison with production aircraft is difficult to achieve. By Ron Wanttaja. 34 under New Management: EFII’s all-new electronic engine control system for Lycomings. By Tom Wilson. 41 pioneer Mechanics in Aviation : A book by Giacinta Bradley Koontz. Reviewed by Bob Hadley. 42 spars—The Heart of the Wing: Laying out the spar, part 2. By Paul Dye. 48 r apid Prototyping and Experimental Design: Sandwich panels, part 5—a simple, accurate method for molding flanged parts. By Eric Stewart. 66 c ompletions: Builders share their successes. 72 ask the DAR: Repairman certificate eligibility, ELSA mods, flying at civil twilight, fuel cap engraving. By Mel Asberry. Shop Talk 53 The Creative Homebuilder: Make your own air-flow speed control. By KITPLANES® Staff. 54 Plane and Simple: Drilling in tight places. By Jon Croke. 56 Maintenance Matters: Three battery problems lead to accidents. By Dave Prizio. 60 Home Shop Machinist: Spline-al tap. By Bob Hadley. 76 Aero ’Lectrics: Spread those sheets. By Jim Weir. 79 Unairworthy: Throttle interference. By Vic Syracuse. Shop Tip 55 magnet Clamps: By David Paule. 6 Designer’s Notebook 73 Wind Tunnel: Design process, part 4—more about speed. By Barnaby Wainfan. Exploring 2 Editor’s Log: Perspective. By Paul Dye. 63 Checkpoints: Last action taken. By Vic Syracuse. 78 rear Cockpit: Layoffs, I’ve had a few. By Tom Wilson. Kit Bits 4 Letters 67 list of Advertisers 68 builders’ Marketplace 42 80 Kit StufF: Drawing on experience. By cartoonist Robrucha. On the Cover: Durand Mark V staggerwing photographed by Richard VanderMeulen. For subscription information, contact KITPLANES® at 800/622-1065 or visit www.kitplanes.com/cs. KITPLANES March 2018 1 EDITOR’s LOG Perspective There’s nothing like an airplane in the trees and rocks. Hiking out to give you a better perspective after an off-airport landing might of the world—the big picture, so not be the wisest thing to do, so to speak. I thought of this recently long as you are reasonably certain while listening to a new audio book that someone knows where you on the Donner party, the group of are. Standard 121.5 ELT? I wouldn’t emigrants who got themselves count on it. Even if it works, I stuck in the Sierra Nevada winter have known of search efforts that of 1846. They were actually early in couldn’t find one before the bat- the westward migration, and were teries ran out. Far better to carry among the first on the route across a GPS-enabled personal locator the Great Salt Lake and Desert. To beacon; it will bring searchers right be honest, they made just about down on top of your position. every bad decision they possibly Lesson number two from the could, which brought them to Donner party has to do with think- what is now the town of Truckee, ing about all available options. California (on the shores of today’s If you look at pictures, the road Donner Lake), just as the worst west was perilous—as I men- winter they had ever seen closed tioned, granite escarpments and in on them. cliffs that today are a huge draw Imagine being stuck in a white- for rock climbers from all over out that lasted for days and built the area. On the weekend, you snow depths of 12 to 20 feet. Ahead Looking west toward California’s Donner Lake. During can’t find a place to park for all the the winter of 1846–47, the Donner party camped on of you, the valley ends in granite climbers. And once you cross the the east shore (foreground) at what is now known as escarpments that would be difficult Donner Memorial State Park. (Photo: Paul Dye) pass, it is downhill to the pleasant to climb alone—much less having Central Valley of California. But if to bring wagons and oxen along. It was a the summit of the pass. The emaciated you pick the wrong drainage to follow, brutal place that winter, and the trials and settlers who attempted to hike out to you are in an inescapable canyon wil- tribulations they went through fill many the west after a month of being stranded derness that will stop all forward prog- volumes. That nearly half the party sur- took two days just to cross the lake, and ress and not leave a place to climb out. vived to be rescued is amazing. then two more days to climb the gran- This is exactly what happened to the What I find most interesting about ite. What we can cross in minutes was a desperate settlers of the Donner party. this—and why aviation comes into it— lifetime for them. And the amazing thing Their relentless effort was directed is seeing it all from the air. On a recent about seeing it from the air is that it sim- westward, always westward. November morning, it took me about ply doesn’t look that hard. Yet to the east, it was a fairly gentle eight minutes to fly from the lowlands That brings us to lesson number one descent along a trail they had already to the east (Truckee Meadows, better for those flying over hostile terrain: The used down into the Truckee Meadows of known today as the City of Reno) to Don- world looks small from up in the air—but what is now Nevada. While winter there ner Lake, and two minutes more to reach it gets immensely larger if you are down is certainly a bit chilly, and they’d still face

Paul Dye, KITPLANES® Editor in Chief, retired as a Lead Flight Director for NASA’s Human Space Flight program, with 40 years of aerospace experience on everything from Cubs to the Space Shuttle. An avid homebuilder, he began flying and working on airplanes as a teen, and has experience with a wide range of construction techniques and materials. He flies an RV-8 that he built, an RV-3 that he built with his pilot wife, as well as a Dream Tundra they completed. Currently, they are building a Xenos motorglider. Paul Dye A commercially licensed pilot, he has logged over 5000 hours in many different types of aircraft and is an A&P, EAA Tech Counselor and Flight Advisor, as well as a member of the Homebuilder’s Council. He consults and collaborates in aerospace operations and flight-testing projects across the country.

2 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes the task of building shelter, there was have turned around (it’s that “slow but we’d also run out of service ceiling— game aplenty and a much better chance boiling frog” thing—we suddenly find and had to make the decision to retreat of survival. But they never even seemed ourselves in a place we wouldn’t be if back to where we started (200 miles to consider the option of turning around we knew how bad it was going to get). distant) because there were no other air- and retreating until spring. Instead, as We figure it’s been bad, but we can ports along the way. It was a tough call— those who have heard the term “Don- tough it out for a little longer. And sud- but the right one, in the end. ner party” know, some of them ended denly, we’re trapped—in the cloud, low When you find yourself in a situation up resorting to cannibalism to survive. to the ground, and not certain where where you’d rather not be, it’s impor- Pretty desperate measure to avoid back- there might be towers or rocks. The tant to look at all your options—ahead, ing up or turning around. But keep in right thing to do is turn around—but behind, and to the sides. No destination mind, they had just crossed a vast wilder- we know it was bad back there, and we is so important that you should take the ness, filled with wild beasts and “danger- don’t want to face that again! Just a little chance of dying to get there. Live to ous savages” (despite the fact that the farther, and we know our destination fly another day, another year, another Native Americans had actually helped will be in sight. The lure of the destina- decade. Most importantly, turn around them at times as they crossed the conti- tion is strong, and it has killed many a early. Don’t let yourself get trapped nent). To them, turning back meant div- pilot—and their trusting passengers. where it’s bad and appears to be better ing back into a great unknown—with I once made a flight over the moun- ahead, but really isn’t. It is so easy to get the prospect of western civilization just tains where my departure point and des- sucked into a situation where no good 50 miles ahead. tination were clear, but broken layers of options exist. It must be, because it keeps Have you figured out why I bring this cloud persisted in between. The terrain on happening to good people who must up yet? Aviation can often present us was too high to reasonably file IFR, so we have just let their guard down for one with the same situation. We’ve strug- set out and had a good time on top, with reason or another. gled through weather that is closing breaks in the clouds below most of the Don’t be afraid to turn around and let in on us, and there are just a few more way. But the clouds kept climbing and so some ground go, or—like the Donner miles to go to our destination. We’ve did we. It finally got to the point where party—you’ll be trapped in a valley of already pushed on when we should we were 50 miles from our destination— your own poor decision-making. J

KITPLANES March 2018 3 LETTERS

EDITORIAL Editor in Chief paul Dye Coming Back indicator is not damaged, but it is not [email protected] I really appreciated LeRoy Cook’s article checked or required to be checked. OK, Executive Editor mark Schrimmer on returning to the cockpit after a long you can hit the “delete” button now. Art Direction Dan Maher break [“Coming Back,” January 2018]. A Thanks for listening. Editorial Director paul Bertorelli few years ago I came back after seven years Jim Averett Contributing Editors larry Anglisano, Marc Ausman, leRoy Cook, Jon Croke, of not flying for various reasons. After robert Hadley, Dan Horton, about three hours in a 172, I evidently Yeah Jim, it’s picky. Correct, but picky. louise Hose, Amy Laboda, scared the instructor bad enough to clear However, sometimes I get in the mood to Dave Martin, Sid Mayeux, David Paule, Dave Prizio, me. Not long after that, I purchased a be picky, too. For example, it’s a condition Ken Scott, Elliot Seguin, very nice Tri-Pacer. A friend went with inspection, not a conditional inspection. Dick Starks, Eric Stewart, Vic Syracuse, Barnaby Wainfan, me to pick it up (only about an hour-and- There’s nothing conditional about it. Then Jim Weir, Tom Wilson. a-half flight home from Detroit). He flew I get a beer and relax on the porch!—Ed. Web Editor Omar Filipovic most of the way while I just got used to Cartoonist Robrucha being up again. I took it in for the land- Lithium Batteries ADVERTISING ing at Y70 (Ionia County, Michigan) Many thanks to Jared Yates for writing Sr. Advertising Manager Chuck Preston and really did it right. It took a good 30 a clear and concise article on the EarthX 805/382-3363 [email protected] hours for me to feel back at home in the batteries. [“Understanding Lithium air, even with several hundred hours and Batteries,” December 2017] Great job! BUSINESS OFFICE Ken Ryan Belvoir Media Group, LLC many types of birds in my log—instru- 535 Connecticut Avenue ment rated and all. I now own a Cygnet Norwalk, CT 06854-1713 SF2A and only have 15 hours or so in it. Lithium batteries are a source of emo- EDITORIAL OFFICE Almost feels like starting again, but it is a tional angst for many. We thought that 535 Connecticut Avenue gentle thing, and we are getting to know clearing the air by focusing on the pros Norwalk, CT 06854-1713 each other…carefully. and cons of LiFePO batteries would [email protected] 4 Doran Jaffas bring some real data to the discussion. CIRCULATION We’re glad that you found it useful.—Ed. Circulation Manager Laura McMann Picky, Picky, Picky! SUBSCRIPTION DEPARTMENT I realize this is very picky but I guess it More From Dave Anders 800/622-1065 is a pet peeve of mine. In Dave Prizio’s Just ran across a spreadsheet I did years ago www.kitplanes.com/cs P.O. Box 8535, Big Sandy, TX 75755-8535 excellent article [“Getting Your Plane that covers changes in performance for my For Canada: PO Box 328, Norwich, Ontario N0J 1P0 Ready for the DAR,” October 2017], he RV-4 from 1993 to 2000. All data is from mentions that “a pitot/static certifica- races, primarily the Sun 100 Air Race. I REPRINTS FOR PUBLICATION AND WEB POSTING AVAILABLE tion is not required unless you plan to fly don’t know if this would be of interest to Minimum Order: 500 IFR.” I find no mention of a pitot check your readers, but feel free to share it. Contact Jennifer Jimolka, 203/857-3144 in Part 91 of the FARs. The required Dave anders certification for IFR in 91.411 is for the Change of address? static system and has nothing to do with Thanks, Dave! We posted the spreadsheet Missing issue? the pitot system. I think many pilots www.kitplanes.com/anders-RV4 Subscription Question? at . believe that when they get 91.411 certifi- For more about reducing drag and going Visit www.kitplanes.com/cs. cation, the airspeed (pitot system) is also faster, see Dave’s articles in the March, Or call 800/622-1065 from the U.S. and Canada. checked. Of course, this is not the case. September, and October 2017 issues of During the test, the pitot is connected KITPLANES®. Also see Nigel Speedy’s Foreign 903/636-1112 or fax to the test equipment so the airspeed 203/857-3100. story on page 22 in this issue.—Ed. J

Website Information: General homebuilt aircraft information, back issue availability, online directories ordering info, plus a Kitplanes® article index and selected articles can be found at www.kitplanes.com. Unsolicited manuscripts: are welcome on an exclusive basis, but none can be acknowledged or returned unless accompanied by a stamped, self-addressed envelope. No responsibility is assumed for loss or damage to unsolicited material. Kitplanes® (ISSN 0891-1851) is published monthly by Aviation Publishing Group, LLC, an affiliate of Belvoir Publications, 535 Connecticut Avenue, Norwalk, CT 06854-1713, Robert Englander, Chairman and CEO; Timothy H. Cole, Exec. Vice Pres./ Editorial Director; Philip L. Penny, COO; Greg King, Exec. Vice Pres./Marketing Dir.; Ron Goldberg, CFO; Tom Canfield, Vice Pres., Circulation. Periodicals postage paid at Norwalk, CT, and at additional mailing offices. Copyright ©2018 Aviation Publishing Group, LLC. All rights reserved. Reproduction in whole or in part is strictly prohibited. Printed in USA. Revenue Canada GST Account #128044658. Canada Publishing Agreement #40016479. Subscriptions: One year (12 issues) is $29.95 U.S. $41.95 in U.S. funds in Canada, includes GST. $41.95 in U.S. funds for Foreign Surface Mail or $57.95 in U.S. funds for Foreign Air Mail. Single copy price $4.99 U.S., $5.99 Canadian. POSTMASTER: Please send address changes and subscription inquiries to: Kitplanes®, P.O. Box 8535, Big Sandy, TX 75755-8535, or Canada Post: Return undeliverables to P.O. Box 2601, 6915 Dixie Rd, Mississauga, ON L4T 0A9 or call 800/622-1065. Kitplanes® is a registered trademark of Aviation Publishing Group, LLC.

4 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes YOUR AIRPLANE WAS A JOY TO BUILD. WE MADE SURE IT’S A JOY TO FLY, TOO. Here at Team X we’re not just engineers. We’re also pilots and builders, so we design avionics we want to fl y behind. And when you see what we’ve created — from fl ight displays to radios, autopilots, GPS navigators and audio panels, and everything in between — you’ll fi nd we have just what you need for your project, too. Visit us at Garmin.com/Experimental.

17-MCJT910 Team X Joy Ad-7.875x10.5-Kitplanes.indd 1 8/2/17 8:34 AM Durand Reinstatement

6 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Planning a kit for the unique Mark V negative-stagger biplane. By Scott M. Spangler

Instead of a tailwheel, it sits on tricycle landing gear. Its Swatosh acquired the airplane, all 92 sheets of the original biplane wings are set backwards in a negative stagger. There plans, and the rights to the airplane from Jim Durand in 2013, are full-span flaps on the upper and lower wings, and spoilers three years after his father passed away at 96. instead of ailerons. And the large canopy slides forward. The Swatosh first saw the airplane in a storage unit in Balsam Durand Mark V is unlike any other airplane seen since its Lake, Wisconsin, just across the St. Croix River from his home designer, William H. Durand, introduced it at EAA Oshkosh in Stillwater, Minnesota. Even in its dismembered state, the in 1978. Nearly 40 years later, it caught the eye of homebuilt design captured Swatosh’s heart, “like that 1940 Ford you see flight line passersby at EAA AirVenture Oshkosh 2017 when going down the street when you’re a kid.” Durand Industries LLC reinstated its existence with plans and When he acquired the airplane, Swatosh didn’t think about the ultimate goal of a kit. selling plans and producing a kit until he learned more about The company is recreating Durand’s fifth design in Solid- the designer, whom he reverently refers to as “William.” By Works, said Jim Swatosh. The 3D CAD files are the first step 1987, Durand had sold 75 sets of plans; that number grew to 91 in turning the scratch-built design into a kit. There is no hard in 1998. As near as Swatosh can tell, approximately 12 Mark Vs timeline to this goal, but plans are available now. were built, including five confirmed flyers. Swatosh owns two Swatosh learned about the airplane during the resolution of of them, Durand’s prototype, and another, built in Canada, a business issue unrelated to it. Without going into the details, which flew on floats.

Photos: Richard VanderMeulen and Scott Spangler KITPLANES March 2018 7 Built in 1978, government surplus instruments fill the Mark V’s Jim Swatosh demonstrates the forward-sliding canopy and panel. The brake lever extends below the throttle quadrant. unobstructed ease of stepping into the cockpit. What he most admires about the recreate missing parts, like the left sta- A Practical Airplane Mark V is that “everything is designed; bilator, and reassemble an Experimen- for the Amateur Builder it wasn’t thrown together,” said Swa- tal/Amateur-Built aircraft. Nick Jilek is That is how Durand summarized his tosh, an appreciation born of his career now the airplane’s mechanic and pilot. clean-sheet design. Its mission is “day in business and manufacturing. Beyond Working from his hangar at Wiscon- VFR pleasure flying with lots of visibil- that, “my history has been restoring old sin’s New Richmond Regional Airport, ity,” and a panel with room for avionics things,” he explained. “I’ve restored a lot also across the river from Stillwater, and (large government surplus) instru- of century-old homes; the Durand is a Jilek made his first homebuilt test flight ments necessary for occasional IFR fly- different sort of restoration.” in 1982 and “averages 350 hours a year ing. Instead of making builder-pilots and The Mark V has also reinvigorated in everything from a Mooney Mite to their passengers adapt themselves to the Swatosh’s aviation aspirations. In 1978, the [twin turboprop] Merlin.” airplane, he adapted the airplane to their he was a student pilot who’d soloed and It was chance that introduced Swa- needs through a “unique but purposeful logged 20 hours of dual. Life postponed tosh and the Mark V, but it’s a good kit combination of old and new—negative his private pilot certificate, which he is candidate because Durand designed it stagger cabin biplane with modern full- once again pursuing. specifically for the scratch builder. He span flaps, spoilers, stabilator, forward- His initial efforts to reunite the explained this in detail in three EAA sliding canopy, tricycle landing gear, and Durand’s parts revealed that not all air- Sport Aviation articles in 1978-79, which all-metal construction.” frame and powerplant mechanics have are on the Durand Industries website, With the negative stagger and a can- the knowledge and skills necessary to www.DurandMarkV.com. opy that rolls forward smoothly on the

The Durand Mark V outside Nick Jilek’s hangar at Wisconsin’s New Richmond Regional Airport.

8 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes With the brake lever extending below, the throttle quadrant When stepping on a rudder pedal, the “inactive” pedal moves holds the parking brake, throttle, and mixture. only slightly in the opposite direction. drawer rails of an office filing cabinet, with the horizon when the airplane is a rudder pedal. So in the Mark V, full pilots and passengers can step effort- in the correct attitude for a minimum deflection of the “active” pedal causes lessly into the 44-inch wide cockpit speed touchdown.” the “inactive” pedal to move aft only without bending or folding their bodies, Still, like many homebuilts, the Mark slightly. With dual sticks, all of the other bumping their heads, or leaving a muddy V embodies its designer’s personal pre- controls are conventional. Along the footprint on a seat cushion. (Replacing dilections. “I suppose that most pilots bottom edge of the panel, spring-loaded the missing steps that extend forward of would prefer toe brakes” (and Jilek leads map pockets double as padded knee pro- the leading edge is on Jilek’s to-do list.) that list). But Durand wrote that he too tectors, and the four-position flap handle “I have rated gentle flying characteris- often rode them unintentionally, so the and trim lever are between the seats. The tics, short-field capability, personal com- Mark V has a brake lever. Connected to trim lever controls the stabilator’s anti- fort, cross-country usefulness, occupant a single master cylinder, the lever extends servo tabs. “Its position indicates the safety, and structural simplicity more below the center quadrant that is home amount of trim…and [it] acts as a minia- important than extremely light weight, to the parking brake lock, throttle, mixture control stick,” Durand wrote.” Jilek high cruising speed, or other strictly ture, and carb heat. A steerable nosewheel seconds this. competitive numbers,” wrote Durand. guides the way, and all three gear legs are Given its canopy, ventilation is cru- He designed visual references into the sawn from thick Scotchply, a 3M compos- cial. Bilateral plenums supply temper- airplane. The forward-sloping cowl ite material used for the same purpose ature-controlled air to the sidewall parallels the ground line between the on Grumman American two-seaters. vents. A diverter sends defrosting air to tailskid and main gear. For an average- Durand also did not like bending an the windshield. The cabin airflow exit height pilot, “this flat surface will align ankle backwards when he pushed on control is in the overhead console with

Cutaway view of the Durand Mark V.

KITPLANES March 2018 9 (Left) The overhead console is home to the radio speaker, panel and cockpit lights, and the knob that controls the amount of air that leaves the cockpit. (Right) The overhead cam latch that secures the canopy has a second notch to provide additional ventilation during taxi. a speaker and cabin and panel lights. A solution to the problems associated with lift contribution from a 50-50 situation second detent on the canopy’s overhead airplane design.” to about a 53-47 basis, with the lower locking cam latch holds it open a bit for In addition to easy entry, the nega- wing being slightly more effective.” increased taxi ventilation. tive stagger contributed some “desir- When the angle of attack approaches able aerodynamic characteristics [such the stall, Durand wrote, the airplane Designed for Garage Construction as] inherent flare-out at touchdown, does not rely on one wing for all of its When designing a homebuilt, Durand flaps that don’t require a trim change, lift. The lower wing stalls a few degrees wrote, designers must consider the range and excellent anti-stall properties.” before the upper. In this situation, the of possible builder-pilots and their shops. Those full-span flaps were important to upper wing becomes more effective; “His flying experience may be limited, Durand. “Since the airplane was going being “behind the CG, its lift causes a and his experience as an airplane builder, to be based and test flown at my back- nose-down pitch while working at or nil. Everything considered, the [pulled]- yard grass strip, Durand Sky Ranch, near its maximum lift coefficient.” riveted all-metal biplane seemed to short-field capability was a must.” This not only reduces the altitude offer the right combination of compact Explaining the negative-stagger aero- lost in stall recoveries, it delivers an dimensions, general wing area, and sim- dynamics, Durand noted that the lower “inherent advantage” on landing. ple, clean, odor-free construction result- wing is ahead of the CG and the upper Approaching the runway, ground effect ing in a really durable machine.” wing is behind it. While both wings acts on the forward lower wing, gradu- Members of EAA Chapter 80, which have the same span, chord, and angle of ally increasing its lift. Acting ahead of Durand helped found in Omaha, incidence, “the actual angle of attack is the CG, “it gently raises the nose for Nebraska, built the prototype on a different [because] the trailing wing is what might be termed an automatic “4x8-foot plywood table in a 14x18- working somewhat in the downwash flare requiring little, if any, help from foot shop that also included a work- of the leading wing. This changes the the pilot.” bench, drill press, stove, and our local EAA chapter library.” Builders will need more room for final assembly, a bending brake, and a welding kit for the control fittings, engine mount, and exhaust system. With the negative-stagger biplane’s 24-foot-6-inch wingspan and 36-inch wing chord limiting the travel of its center of pressure, Durand wrote that the Mark V’s shorter, lighter, less expensive 20-foot-3-inch fuselage does not sacri- fice stability. Investing nearly four years designing it, “stress analysis and weight and balance calculation paralleled the continual modification of the layout to achieve the simplest and most direct There are separate heat and airflow controls for each seat.

10 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes

Durand Mark V

Plans price (92 prints) ...... $350.00 Estimated scratch-building time ...... 3000 hours Estimated completed price (firewall back) ...... $28,000–$35,000 Known number flying (at press time) ...... 1 Powerplant . . . . . Lycoming O-320, 150 hp @ 2700 rpm Propeller ...... Fixed pitch

AIRFRAME Wingspan ...... 24 ft 6 in Wing area ...... 144 sq ft Fuel capacity (without optional wing tanks) . 24.5 gal The right spoiler in full deflection. The control surface behind it is a full-span flap. Maximum gross weight ...... 1840 lb Typical empty weight ...... 1210 lb Upper and lower full-span flaps not easy access for maintenance and servic- Typical useful load ...... 630 lb only slow landing speed (and landing, and a quick but thorough preflight Full-fuel payload ...... 483 lb ing distance), they eliminate the need inspection. He mounted the battery, Seating capacity ...... 2 for trim changes often necessary when for example, in a swing-out box in the Cabin width ...... 44 in extending partial-span flaps, which tail cone, so builders can service it out- Baggage capacity ...... 128 lb change the wing’s center of pressure. The side the airframe and not have to worry Mark V proportions “the lift of the two about a prop strike when jump-starting PERFORMANCE staggered wings in the flaps-down mode the airplane in cold weather. At the other Cruise speed ...... 135 mph so that their composition center of pres- end, to change oil without removing the Maximum rate of climb ...... 1200 fpm sure does not move rearward.” Durand cowling, there’s an opening aligned with Takeoff distance (grass field) ...... 550 ft did this with different full-flap deflec- the sump quick drain. Landing distance ...... 450 ft tions, 40 degrees on the upper and 45 Service ceiling (estimated) ...... 15,000 ft degrees below. Three Subassemblies Specifications and pricing provided by the manufacturer. Full-span flaps made spoilers as the The Mark V fuselage is composed of only roll option. The simple flap is 4.75 three subassemblies: the cockpit, the bottom skin join with keel channels to inches wide, 69.5 inches long, and hinged baggage area and cabane, and the tail create a box beam that runs the length at the leading edge. Operating individu- cone. Durand compared the cabin of the cockpit and provides attachments ally, full deflection is 40 degrees. assembly to framing a house, with “a for the lower engine mount, nosewheel, Building the prototype “tested the center girder, floor joists, and wall studs and Delrin control bearing. plans and revealed dimensional errors, [2.5-inch channels drilled for wiring], The wing employs a two-piece spar inadvertent omissions, and related and a top plate.” For occupant protec- comprised of 0.050-inch material bent improvements.” Given his “I’d rather be tion and structural stiffness, the cockpit into modified J-sections joined by pulled flying preferences,” Durand focused on is skinned inside and out. The floor and rivets. Builders can fabricate each spar Durand’s First Four William H. Durand designed and built his first airplane in 1934. The 20-year-old soloed the single-seat, spruce-and-muslin, high-wing glider after 4.5 hours of dual in a Waco. It served the Omaha Aero Club for three seasons before a windstorm dismembered it. An engineering student at the University of Omaha, as a self-education project, Durand designed the A-45 in 1936–38 to CAA airworthiness requirements. He built the tube-and-rag two-seater, powered by a 45-hp Szekely radial, in 1940. He later traded it for his first car. Founding the University of Omaha’s aeronautics department, Durand taught aerodynam- ics, aircraft drafting, woodworking, welding, and engines. Named for its Continental engine, he designed the C-40 in 1942, and his students built the single-seater’s tube fuselage and cantilever wood wing. Durand designed the X-85 in anticipation of the post WW-II boom in general aviation. Sitting on tricycle gear, a Continental C-85 pushed the low-wing, all-metal, side-by-side two- The trim lever and flap handle are in the seater. The airplane was stillborn in the late 1940s, when the boom went bust. console between the seats. —S.M.S.

KITPLANES March 2018 11 The open cowl doors provide easy access to the Lycoming O-320. Like the nosewheel, the main wheels are bolted to the Scotchply gear legs. Also visible is the glasspack muffler. in its full 10-foot length or in shorter in place prior to their incorporation into legs bolted to a steel carry through that sections using the low-stress splices indi- the structure.” absorbs all the bending stresses. Alu- cated in the plans. The rear spar and flap To make subassembly alignment easy, minum saddles mate this chassis and spar are formed of 0.040-inch stock. The the fuselage bottom is flat from the the fuselage. An automotive glasspack 0.032-inch leading-edge channels are tailpost to the firewall. The prototype’s muffler is located between the main nonstructural; they align the nose ribs builders aligned the tail cone and for- gear legs to mute the roar of the 150-hp during assembly. Since all four wings ward fuselage on a one-piece aluminum Lycoming O-320. are the same, builders need only one rib ladder supported by two sawhorses. Scratch building is the first of three form block. Except for the lower wing They adjusted the subassembly align- options for building the Durand Mark walkways, the wings are skinned with ment until the canopy rails were even. V. The plans include hardware and mate- 0.020-inch Alclad. The canopy looks like blown Plexiglas, rial lists and diagrams for getting the Builders fabricate the tail cone from but it is 1/8-inch Lexan cut and bent cold. greatest number of parts out of 4x12- the bottom skin up. They mount the A tough, pliable polycarbonate, Lexan foot sheets of metal. As the SolidWorks bulkheads to this skin, which eliminates costs more than Plexiglas, Durand CAD effort continues, Durand Indus- the need for an assembly fixture. Only wrote, “but you don’t have to build or tries will incrementally offer complex straight bends form the parts of this borrow an oven to heat it before bend- and welded parts, and then kits, said stressed-skin structure. Except for the ing.” The canopy frame holds it in place, Swatosh. “I just found a company that back channel that runs across the top of and its curvature produces a rigid surface makes rotationally molded polyethylene the bulkheads, primarily as an assembly that eliminates the need for corner posts fuel tanks.” Made of welded aluminum, convenience, there are no longerons or that would block the occupants’ view. “the Durand fuel tank is a work of art, stringers, “only skin stiffeners between The main landing gear is essentially but it takes time to build, and I want to the frame locations, which are riveted an independent chassis, with Scotchply give builders options.”

12 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Got Wings? Here’s what you get in EVERY ISSUE of KITPLANES ® • Aircraft Flight Reviews • Construction Hints & Tips • Hands-On Projects • The Latest in Avionics • New Products for Experimentals • Real-World Builder Experience

Expert advice on how to plan, build and complete your own aircraft!

Subscribe to KITPLANES® and receive these extras: • Unlimited online access at www.KITPLANES.COM • FREE access to our Editorial Archive of articles • FREE searchable Aircraft Buyer’s Guide • FREE searchable Supplier Directory

For fastest service, visit us at www.kitplanes.com/subscribe or call us toll free at 800/622-1065

KITPLANES March 2018 13 Flying the Durand Mark V Modern kit aircraft are, for the most part, thoroughly developed, well- sporty with the flaps extended, so the Durand team had decided to fly behaved machines. We’ve learned a lot over the years that has helped it without flaps until that was sorted out. That meant higher takeoff designers improve their manners to the point that they can behave and landing speeds, but nothing out of the realm of the ordinary, 80 reasonably well in mixed company (mixed being a variety of pilot skill knots being the preferred number on final. With roll control provided levels). There are very high-performance machines that have significant by spoilers and pitch inputs handled by a stabilator, it is unusual, but quirks because of what they are, and those quirks are accepted in order not outside of accepted practices. to make the plane as fast as possible, or something that can win at The owner’s demo pilot at AirVenture offered to fly along with me unlimited aerobatics—but the average pilot’s average airplane should (the owner not being licensed). Since the takeoff and landing charac- generally meet the handling requirements of the accepted norm. teristics were (as mentioned) a little tricky, I let him do those phases This isn’t really true of older designs that are beginning to look of flight. As we climbed away from Oshkosh on a beautiful morning, downright ancient when you consider that more than a generation surrounded by airplanes departing the annual EAA convention, I took has passed since they were conceived. The Durand is this kind of the controls and immediately realized that the pitch channel was aircraft, an interesting concept combining old biplane technology quite unusual. with newer construction techniques to produce an airplane that Without a lot of backup data for this acquired plane, there isn’t a was intended to be stall proof in the time of Rutan’s work doing the consensus on the actual CG range, but it felt like it was loaded a bit same thing with canards. There are estimated to be about 12 Durand aft. The airplane was statically neutral in pitch, with very light forces. Mark Vs built and two more currently under construction, but no one Dynamically, it felt as if an oscillation wanted to develop in pitch with knows how many might be flying today. Two of them are now owned increasing speed, so we limited ourselves to a point where it seemed by Durand Industries LLC, although one is currently disassembled. comfortable (100 knots) and performed the rest of our mission (a The particular aircraft we flew was built in the 1970s and spent photo flight) at that speed or below. Adding power tended to create a decades in storage before being purchased in an estate sale by the bit of a porpoise since it meant we sped up into the dynamic range, so current owners. It was, they report, in good shape, but was missing formation flying was tricky. one half of the stabilator, which they replaced using the plans set It had been a long time since I had flown an aircraft with spoilers for they had acquired. roll control, so I was curious about what to expect. It turned out that the airplane was controllable, but the stick had an unusual feel. There First Flight Review was a narrow dead band in the center, and as you pushed to add a roll With the Durand Mark V repaired and back in the air, I was invited to input in either direction, nothing happened until you pushed just a fly it. During the preflight briefing, I learned that things got a little little bit harder than you expected—and then the spoiler popped up

14 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes to enact your desire to roll. The effect was that there was a detent of some sort, making it hard to add a smooth input in either direction. The rudder, on the other hand, has a smooth, natural control feeling like any rudder on any airplane. Trying to coordinate it with the somewhat ratchety roll control was the only unusual bit about that channel. But adding rudder alone, as is often done in formation, made the airplane want to roll, demanding stick input which exhibited that detent feel. Needless to say, it took some attention. Our concern was primarily with what seemed like stabilator instability, and the fact that the motion was oscillatory with increasing amplitude really caught our attention, this being a good description of the onset of flutter. After this flight, we huddled with the Durand team and were told that when they found the airplane, it was missing of what feels like instability, it stops accelerating away—a very odd the left stabilator. A new one was fabricated and installed, but further control feel. While manageable, it is certainly not very desirable, and investigation showed that the bolt holes in the torque tube were wal- the folks at Durand seem to understand this. Rather than try to deal lowed out, and the control surface was able to move on the tube. Any with a landing immediately after takeoff with the odd control feel, loss of stiffness in this fashion could easily lead to a flutter situation, so we elected to climb out and evaluate the airplane with some altitude we excused ourselves from further flying at the show and said we’d be underneath us before returning to earth. happy to fly the airplane again once this was addressed. After a few minutes of “getting the feel,” we had adapted enough for some slow flight, and some nibbles at power-off stalls. Here we Second Flight Review learned that the odd pitch forces were related in some way to the prop It was a beautiful bright fall day in western Wisconsin when we next wash, for when we pulled the power back, the unpleasant pitch forces saw the Durand and checked out the repairs, which had been done in reverted to a much more normal feel. Essentially, in gliding flight, the the ensuing months. We again climbed into the plane for an evalua- airplane behaved as you’d expect for a typical light plane. After our tion flight. In addition to the stabilator torque tube repair, the team flight, we noted that the stabilator panels on each side are almost had also rerigged the spoilers for more symmetrical deployment, an square—short span, large chord—and it might be that they need to issue they had found that we had not observed. add more span to add stabilator surface outside of the slipstream. One The prototype aircraft has a comfortable cockpit, with good hypothesis is that with the current axis of rotation (about the torque visibility out of the frameless forward-sliding canopy. With the upper tube), there is enough surface area ahead that when you move the wing mounted aft of the cockpit, it was almost like flying in a bubble stabilator, the prop wash “grabs” the leading edge and attempts to canopy—especially since we seem to be able to swivel the head less move the surface in the direction you are going, but with more force with age. The panel is, as you’d expect from a 1970s aircraft, a bit than is appropriate. antiquated, with a large four-inch attitude indicator that sounded Regardless of the causes, Durand LLC told us that they will be hiring like a turbine engine spooling up. All of the basic controls are there, outside aerodynamic consultants to evaluate the problem and come and the throttle is mounted to a quadrant to give a little more of a up with a solution to make the airplane handle more like what the big-airplane feel. The trim is actuated by a lever, as are the flaps. typical pilot is used to. This is an excellent attitude, and a very good As was common in many earlier aircraft, the plane is equipped with idea, since the current characteristics could catch an unsuspecting, a single hand brake instead of differential toe (or heel) brakes, but the inexperienced pilot very much unaware—which brings us back to nosewheel steering proved adequate for control on the ground. It is a where we started. In the earlier days of homebuilding, just getting an bit heavy, but manageable, and we found our way to takeoff position airplane finished was a monumental achievement. If it flew, that was without any trouble. even better. If there were deficiencies in the handling qualities, the We elected to keep the flaps up for takeoff, and as speed built, the pilot generally adapted to the airplane, rather than going to the work airplane flew off the ground in essentially level attitude, with little of finding and fixing the issues. Modern kit (and plansbuilt) aircraft rotation. As we pitched for climb, we once again felt the odd pitch are generally much more mature, having been designed, built, and forces, which I’d describe as similar to those of the spoiler—with a bit tested for a wider and larger audience. Poor handling qualities mean of a detent near the middle and very light to negative forces once you no sales. That’s important to remember when you get the chance to moved the control a fraction. This feel can lead very easily to a pilot fly an earlier design. induced oscillation. Imagine an inverted bowl with a marble balanced Can the Durand be made better? Without a doubt, the answer is yes, on top. Obviously, this is unstable, since if you disturb the ball, it will and the company now selling the plans is committed to making the roll with increasing speed off the bowl. Now put a dimple in the top of airplane safe and well behaved. We’ll be happy to give it another flight the bowl. This will make the marble somewhat stable right at the top, when they get done, and we’ll report back—hopefully with a fine- but once you apply a disturbing force, it will again accelerate down flying, unique aircraft that will turn heads wherever it goes. J the side of the bowl. The Durand feels like this, but after a few degrees —Paul Dye

KITPLANES March 2018 15 NEXRAD For Kit Aircraft Drivers

Free access to weather information can be a tremendous safety tool for wise, cautious pilots. By Myron Nelson

Since before a lot of us were born, airliners have been using onboard weather radar to avoid dangerous storms and turbulence. The early units, while marvels for their times, were bulky, heavy, and expensive. They countered their nascent reception and interpreta- tion abilities with massive wattage output, the axiom being that it was vital to turn off the system before taxiing into the gate if the poor marshaller ever wanted to be able to have children. The displays of the early units were monochromatic with very poor resolution. As the technology improved from vacuum tubes to transistors to integrated circuits and beyond, the features improved, and the need for brute wattage output dropped dramatically. The bulk and size of the units shrank accordingly, allowing corporate-level aircraft to enjoy the benefits of weather detection. The systems eventually became a common albeit expensive addition for many light twins. The expense, plus the fact that there had to be a place for an antenna (the larger in circumference the better), left most of the single-engine market out of the game. There were a few wing pod models installed on Cessna Centurions and Piper Malibus, but I would hate to imag- Airliner weather return of precipitation near Mt. Hood, ine what those units originally cost for the benefit they provided. Oregon (main image).

16 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes (Left) Weather and restricted areas near Lincoln, Nebraska, and Topeka, Kansas, while returning home from AirVenture. (Right) The same information viewed from a different perspective.

Enter NEXRAD to aircraft that have the proper ADS-B I have always loved observing weather. Several years ago, as ground-based radar In equipment installed. Now even Light I find it to be awe inspiring, even spiri- technology improved, the federal gov- Sport Aircraft can have technology that tual at times. Being immersed into the ernment embarked on a program of not so long ago, even the big-iron boys amazing atmosphere is one of the rea- covering the bulk of the country with used to dream about. sons I chose my vocation and my avoca- a network of state-of-the-art weather In a reversal of the historical technol- tion. Having said that, I have learned to radar stations. Today there are 176 sta- ogy trickle down from military to airline respect the immense power of Mother tions in place with relatively few cov- to general aviation, NEXRAD, now Nature. I have no desire to convert my erage gaps (mostly at lower levels near common in newly minted Experimental kit aircraft back into parts, nor one of the mountainous terrain). Other than the aircraft, is just making its way into airline Boeings I fly for a living, for that matter. obvious benefit to aviation and maritime cockpits as a complement to onboard operations, one of the primary goals was radar. We get it mostly through our new What Can NEXRAD Do? to improve dangerous weather advisories EFBs (electronic flight bags), which are Now that any kit aircraft driver can have to whole communities, especially for tor- nothing more than iPads stuffed with access to NEXRAD, how can we use it nadic and hurricane type events where all the manuals and charts we used to to our benefit? The goal of all weather every additional minute of early warning carry in those backbreaking (but cool detection systems is to keep airplanes is critical and can literally save lives. looking) leather Jepp bags. Comparing and their occupants safe and sound. One Using today’s information super- the two types of weather depiction, the important fact that must be understood highway, the data is continually gath- information is complementary, but dif- at the onset is that radar cannot detect ered from all of the reporting sites into ferent. The goals, however, are the same. turbulence. Like a smoke detector that a central site where it is combined with Air traffic controllers also now have a portends fire by the presence of smoke, other forms of data such as satellite version of NEXRAD at most of their radar (I’ll use the term interchangeably data and ground activity reports and terminals, which is a massive upgrade to for ship radar and NEXRAD) can only, dumped into a Cray research-level com- the nearly worthless weather data they at best, indicate where turbulence is likely puter to cook up the graphical depic- had available previously. versus unlikely. It isn’t an absolute science tions that we see today. As NEXRAD was further developed, tweaked, and improved, it started to be more widely disseminated to the point where today it is available for free via several vendors on just about any smart device, as well as modern EFIS screens that have become mainstream, especially in the kit aircraft world. This is another area where our Experimentals are far advanced (and privileged) over our certified brethren. The costs of their equivalent systems can often exceed the costs of our complete aircraft. As most readers already know, NEXRAD is also transmitted for free Downpour rain shaft illuminated by setting sun.

Photos: Myron Nelson KITPLANES March 2018 17 when it comes to airborne hazards. All experienced pilots have been hammered in perfectly clear air and flown through the deepest, darkest deluges with nary a burble. Often the most hazardous spot connected to a particular storm is in clear air adjacent to a storm rather than within its “painted” depiction. It’s All About Water and Lift What weather radar detects and depicts is water—rain, wet snow, wet hail. In contrast, everyday clouds, fog, choppy clear air, etc. do not paint returns, as those elements don’t bounce the signal back to the antenna like water does. Atmospheric water in its own right isn’t Classic weather line with airliner arrival and departure “hole” near moderately busy airport. necessarily hazardous, but H2O is the key ingredient for what is hazardous. beautiful to watch from the flight levels, same area. In theory, the ride quality Remember that insomnia-curing avia- the mushrooming towers can rise at a over, under, or within a patch of green tion weather manual that most of us read higher vertical rate per minute than most shouldn’t be any worse than the prevail- back in the day? The nasty brew starts light aircraft can climb, often spawning ing atmospheric conditions would have when humid air encounters some kind of offspring along the way. The lifting pro- provided absent the painted return. action that causes the moist mass to start cess is called convection, as in the “con- Being within green returns, however, to lift, and then science takes over in a vective sigmets” and the like that serve will most likely mean being IMC (in fascinating way. The lifting action can be to warn us. Not all CBs become TSs, but instrument conditions), which is a haz- from a windy slope, a moving front, the every TS started out as a CB. ard in its own right depending upon the effects of the hot sun baking the fruited capabilities of the airplane and the pilot. plains, or even one of those ubiquitous Green, Yellow, Red Green at the very least means moisture “acts of God” buried in the fine print of The basic colors of NEXRAD and laden clouds that can also present icing our insurance policies. As the air mass onboard radar are built upon the sema- conditions. (See best practices to follow). rises, the gasses expand, condensing the phore trio of green, yellow, and red. Differ- Yellow means heavy precipitation moisture into visible cloud mass and ent vendors have developed further shades and a high likelihood of turbulence. concurrently releasing latent heat, which of the classic three and even a new shade of Yellow is usually the least common color naturally rises and in turn fuels further blue for (calculated) snow, but for simplic- painted overall and often exists in a nar- lifting until the process can become dan- ity’s sakes we’ll stick to the basic three. row band separating red from green. gerously self sustaining and accelerating. Green shows that something is trig- Airline pilots don’t ever plan on travers- In weather reporting, the moist clouds gering a return, but that it shouldn’t be ing through yellow returns, although most with sufficient lifting action become CBs hazardous. From experience of com- have on occasions when the only alterna- (cumulonimbus), then TCUs (towering paring the two side by side, NEXRAD tives were worse. Passengers and flight cumulus), then TSs (thunderstorms) in paints a lot more green over a given attendants have been seriously injured weather shorthand. In a process that is area than does airborne radar over the flying through areas depicted in yellow. General aviation aircraft have no business flying in or around yellow radar returns. Oh Hail No! Red is where the demon lives. Pierce the side of red and flutter out the bottom. A Midwest country bumper painting red has as much kinetic energy within as a nuclear device. There are massive columns of angry air, rain, and likely hailstones that are all soaring skyward and/or even This is a growing “CB” busting up through the stratus layer.

18 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Stay away from areas of painted returns that show tight (narrow) gradients between the Artifact or false positive returns sometimes colors. Those are indicative of shear zones. Also avoid the classic “hook” area. happen with NEXRAD. These small, smooth shapes with no contours or color shad- larger columns of angrier air, heavier rain as the color tones are more translucent ing are random odd weather returns that drops and larger hailstones plummeting for weather, and the respective return actually aren’t significant at all, just normal puffy clouds. to earth at terminal velocity. The shear shapes and textures become more rec- zones of air masses moving in different ognizable with experience. You can also and absolutely avoid severe (red) by directions can spur lightning, tornadoes, toggle the respective layers off and on to twenty miles, especially at the freezing severe turbulence, and can literally break compare and separate the two. level and above. The reason for the buf- an aircraft into pieces. The sheer volume Some displays have indications for fer zones is that turbulence and even of water in such behemoths has hydro- the tops of storms. The higher the tops hail can exist in clear air in the vicinity locked jet engines to the point were the of the storms, the more meteorological of nasty storms. Airliners have a mission laws of physics get angry, and the turn- violence inherent within. There is wis- to get where they need to go. Most of us ing gear ejects itself aft, leaving nothing dom in treating red weather returns as build our kit aircraft just for the pleasure but empty cowlings with a few wires and if they were red terrain returns—pen- of flying and have the luxury of time to hoses flapping in the wind. etrating either will pretty much have be able to give storms a wide berth or Airborne hail can fracture wind- the same result. even elect to fly on a different day. screens or turn them opaque. It can also • One big advantage that NEXRAD • Give special clearance to areas of severely damage and distort airfoil lead- has over onboard radar is that if your painted returns that show tight (nar- ing edges, destroy antennas, etc. system supports CONUS displays, row) gradients between the colors. The best way to tangle with red you can scroll to anywhere where Those are indicative of shear zones. returns is in a simulator, but even there, weather is painting and gain practice Another danger sign is a depiction of if the sim is good, it can knock itself off in observing and interpreting the “hooks” (see photo on above). Give that its own control loading and even dam- results from a safe distance. quadrant an extra wide clearance. age its hydraulics just trying to be accu- • Airline procedures are to try to avoid • Be aware of the OAT (outside air rate in its re-creation of the mayhem. moderate (yellow) returns by five miles temperature). The worst areas for Red rhymes with dead. Enough said. Best Practices • Now that most EFIS systems display both weather and terrain, become comfortable distinguishing between the two since they both use the core green, yellow, and red color schemes and often overlap, which might be confusing to the inexperienced. With practice it becomes intuitive to separate the two, Cumulonimbus (CB) clouds growing in a frontal line.

KITPLANES March 2018 19 (Left) Massive weather area that is very wet but with little convective activity. (Right) One of the dangers of convective activity can be localized icing conditions. hazardous conditions are near the • Be aware of your screen range and Maneuvering underneath a storm freezing level and colder. Rapidly ris- switch it around often. Sometimes a cloud layer is often a gauntlet of rain ing water droplets can freeze an outer decision on the best way to deviate shafts and lightning bolts. shell around a super-chilled, but still your course around weather buildups • Maneuvering underneath stormy areas liquid or slushy, center. When these looks much different at a longer range is not for the inexperienced. There will super-chilled droplets get burst by the than a shorter one and vice versa. often be a mixture of shafts of rain, impact of an invasive aircraft structure, • Being below dangerous weather can be along with “curtains” of lighter rain, they splatter and then freeze, covering as hazardous or worse than being abeam. both of which should paint to varying the aircraft in thick, heavy ice that can Storm clouds appear dark because their degrees on your NEXRAD display. accumulate at an alarming rate. moisture content blocks out light. A However, your Mark One eyeballs • Be aware of the winds aloft. It is gener- scalloped appearance at the base of a are an important safety tool as well. ally more hazardous on the downwind dark cloud is evidence of very turbulent Storms that have nearly dissipated side of a storm than on the upwind conditions. Dangerous storms can be themselves out will often have linger- side. The “anvil” that often appears single entities that are easy to deviate ing remnants of light rain. In daytime, above a mature storm will point around or, more often, exist in packs or a curtain of light rain should still allow downwind and can extend for long frontal lines that can exist for hundreds visibility of the horizon beyond it. distances. Do not fly under an anvil. of miles with dozens of clustered cells. But be prepared for that forward visibility to drop considerably when you penetrate the precipitation, simply for the obscuration on your windshield, which will clear back up when (if) you exit on the other side. All bets are off at night. Shafts of heavy rain are as dangerous as the thunderclappers that produce them and are to be avoided just as judi- ciously. Downpours with rings of dust or visible debris roiling on the ground around them are signs of microbursts and can be lethal even to airliners. • Lightning can occur below, abeam, within, and (rarely) even above thunderstorms. Strikes most often occur in clear air abeam or below the storm, sometimes miles from the mother Classic convective contouring depiction. storm. Some NEXRAD vendors have

20 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Use NEXRAD Wisely For aircraft that already have airborne radar, NEXRAD is a complement, not a replacement. The compilation and dissemination process to get the NEXRAD data to our screens is always improving, but it is at best minutes old in weather that takes mere seconds to change. It is a handy tool for longer- range planning and not intended for close-order maneuvering. Having the opportunity to have free access to NEXRAD information in our cockpits can be a tremendous safety tool for the wise and cautious. Unfortunately, it can also be pixelated courage to the foolhardy. Mother Large weather area outlining the position of the center of the low pressure area. Nature is marvelous to observe from a safe distance, but she always has a few additional lightning depictions in are commonly brownish with one or tricks up her sleeve and loves to get the their displays, but nothing can pre- more dime-sized marks and often a last laugh. dict where lightning will appear in the few more BB-sized ones. When I got my ADS-B module future. The safest position is to simply Other common occurrences associ- installed in my RV-10, I couldn’t wait steer well clear, as in the next state over. ated with lightning strikes are electronic to try it out. When a line of thunder- Airliners are built to withstand “queertrons” that show up hours or days storms was rolling across our area, I lightning strikes, but light aircraft after a strike that cause failures or anom- immediately headed for the airport, and their systems, not so much. If alies in systems or components that at pushed open the hangar doors, fired your airplane is struck by lightning first inspection appeared to work fine. everything up, and soon marveled at in the air, you’ll know it. I’ve been Looking over a ramp of several airliners, how the screen depiction correlated to struck three times in my airline it is not uncommon to see one or more what I was viewing from the cockpit... career, and I remember each one viv- with fresh daps of paint along the top Then the hail started, and I was very idly. There can be a bang like a fast- of the fuselage, often in an arcing line. glad that my airplane and I were still ball thrown at the airplane. If the Pretty much every airliner gets zapped a safe under the protective roof of the strike is within your field of vision, time or two in its career. hangar—that’s unquestionably the best there will be both a flash and a shower These are all good reasons to give a place to be when convective activity is of sparks, and you can be temporarily wide berth to convective activity. in the vicinity. J flash blinded, especially right at the central focus of your eyes as the vision slowly returns from the periphery in. Depending upon where your fresh air intake is, you can even smell the “breath of God” ozone smell that is quite unique. Lightning strikes can melt aluminum and delaminate composite material. I’ve seen a rivet head that melted and flowed back a quarter inch before solidifying again. I’ve also seen a softball-sized bubble formed on the inside of a composite nosecone. If you take a strike, land as soon as practical and have the airplane and all systems inspected by an expert. There will be entry point(s) and exit marks. The marks Funnel cloud over OSH during AirVenture 2014.

KITPLANES March 2018 21 Effect of Fairings on SpeedSpeed

Compared to the high cost of horsepower, reducing drag is a much less expensive way to go faster. By Nigel Speedy

The tests in this article were prompted do, the broken fairing sat under the weight of 1540 pounds and a CG of by several events. Last summer at workbench for a couple of years. Dis- 79.7 inches (forward). Each flight lasted Oshkosh, I was chatting with Paul Dye mayed by the cost of more horsepower, it around half an hour and used approxi- about the effects of aerodynamic fair- seemed like a good time to quantify the mately five gallons of fuel. Every test ings. Not long after this, I was impressed effects of drag reduction. So a little epoxy point was conducted with wide-open by the incremental gains that Dave and paint later, the tailwheel fairing was throttle and 2500 rpm. I began each Anders achieved in his RV-4 and wrote ready for testing. configuration test with mixture full about in KITPLANES® (see “Put- rich, then leaned in approximately one- ting the Experiment in Experimental,” Test Method and Conditions gallon-per-hour increments until the March 2017 and “So You’d Like to Go For these tests, I flew a series of sorties onset of engine roughness (~75° F LOP). Faster,” September and October 2017). in different configurations that I hoped I began the experiment by taking But really, it goes back to an embar- would reduce drag. Each flight was con- off the wheelpants, gear-leg-to-fuselage rassing moment early in my Phase I test- ducted at 10,000 feet pressure altitude. intersection fairings, and fuel drain fairing. Misjudging the length of the RV-8 as Outside air temperature (OAT) at this ings to achieve a practical minimum I swung it around for a runup, I dropped altitude only varied slightly from +37° F fairing configuration on my RV-8. From the tailwheel off the edge of the asphalt, to +41° F (+3°C to +5°C ) across all the there I added the wheelpants and gear- damaging the tailwheel fairing. With flights. I started each flight with 30 gal- leg-to-fuselage fairings, which is prob- seemingly more important things to lons of fuel, which resulted in a takeoff ably how most folks fly their RVs. My

22 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Effect of Fairings on

(Left) Cowling and dipstick access door sealed with vinyl tape. (Center) Fuel drain fairings didn’t improve top speed, but they did improve the aesthetics. (Right) Gap seal tape between the rudder and vertical stabilizer didn’t stay attached above 180 KTAS. aircraft has the Grove airfoil-section number 4489) and then the leading edge tiedown bolt holes were covered. The landing gear, so the gear leg fairings are of the tape was covered with 19-mil- ends of the ailerons, outboard ends just between the top of the gear legs and limeter PVC Safety tape (stock num- of the flaps, and the ends of the eleva- the fuselage. Next, I added Van’s tail- ber 4396). In addition, I taped over tors were taped over to make them wheel fairing. Fuel drain and fuel vent the bottom surface of the flap hinge. flush. On an RV-8, the ends of these fairings from JD Air (www.jdair.com) Last of all, I expended a 36-yard roll control surfaces are concave where the came next. of 2-inch-wide 3M red 471 vinyl tape. outboard rib is attached. The rest of I purchased some 38-millimeter Mylar Axel Alvarez (energetic RV-4 pilot & the roll went on the seam between the gap seal tape (stock number 4441) from Reno Racer #87) provided tips and upper and lower cowl, dipstick access Wings & Wheels (www.wingsandwheels. photos of what to tape up. I started door, and baggage bay door perimeters. com) and added it to both sides of the ele- with the intersections between all fair- vator and rudder gaps. The gap seal tape ings and the aircraft structure. Also Results was attached with the recommended taped over were the two NACA air Flight #1: With all the fairings off, I 16-millimeter double-sided tape (stock inlets for cabin ventilation. The wing was able to get a baseline that I could

(Left) Concave ends of the horizontal stabilizer and elevators were sealed with vinyl tape. A better approach might be to seal these areas with small fairings during construction. (Right) Van’s tailwheel fairing added 1 knot of speed.

(Left) Red vinyl tape applied to the outboard end of the aileron and the wingtip. (Center) Vinyl tape added to the landing-gear-to-fuselage fairing. (Right) Still more tape was used between the wheelpant and Grove airfoil-section landing gear leg.

Photos: Nigel Speedy KITPLANES March 2018 23 Summary of Test Results

Increase in Rated Horsepower Fairing Change in Maximum Speed Required to Achieve Same Change Comments

None Baseline

Wheelpants and landing gear to fuselage fairings +10 knots TAS +18% (36 hp) Too big a gain to ignore

Tailwheel fairing +1 knot TAS + 2% (4 hp) Worth the small price

Fuel vent and drain fairings No discernible change No discernible change Worth it for the looks

Cheap and good for race day, not Vinyl tape +1 knot TAS +2% (4 hp) a practical long-term solution

Wheelpants and landing gear to fuselage fairings had the biggest impact on speed, but even small increases can make a measurable difference.

compare future results to. At the best relatively low cost, light weight, and has the potential to reduce drag, it was power mixture, the plane maxed out at better aesthetics, I think the tailwheel not able to stay attached long enough 177 knots TAS. fairing is worth the effort. to be useful. Perhaps on a lower-speed Flight #2: The addition of wheel- Flight #4: The addition of fuel drain aircraft it would be worth a try. I was pants and the landing gear to fuselage and fuel vent fairings did not make a a little disappointed as modern high- intersections fairings resulted in a big measurable change to the top speed. performance gliders have relatively high jump in top speed, up to 187 knots They certainly add a nice finished look VNE speeds. TAS, an improvement of 10 knots. On to the plane though, so they will stay. Flight #6: The roll of vinyl tape an RV, the speed gain with wheel fair- Flight #5: The flight with glider gap- increased the top speed up to a maxi- ings is pretty compelling, although I seal tape on the rudder and elevator was mum of 189 knots TAS, a further don’t remember the job as being much a bust. As the plane accelerated through 1-knot increase. Not bad for just $29.36 fun during construction. 180 knots TAS, there was a slight buzz- on Amazon.com and an hour to slap it Flight #3: By replacing the repaired ing for a couple of seconds, then it was on. I can see why racers use it, but it is tailwheel fairing, top speed edged up gone. Luckily I prepared for this eventu- not really a good look or that practical just a little to 188 knots TAS, a small ality by writing “Property of USAF” on for more than a couple of flights. I think increase of only 1 knot. Given the each piece. So even if glider gap-seal tape if I were still building, making small fairings to cover the concave ends of the control surfaces would be worthwhile. While I have looked at the change in drag through its effect on top speed, you can also look at how much power it would take to make the same increase. Under the conditions tested, my Dynon Sky- View EFIS calculated the engine power to be 64% of maximum. Let’s assume my trusty Lycoming is rated at 200 horsepower. Under the test conditions, it would have been producing 128 horsepower. Also useful to know is that power required is proportional to speed cubed. To achieve the same speed increase that was gained with all the fairings and tape by brute force would require an additional 22% or an increase in rated power of 44 horsepower. Of the two methods, fairings are by far the cheapest, most effi- Reducing drag by adding fairings increased speed without increasing fuel burn. cient, and elegant way to gain speed.

24 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Safety One hazard of conducting a test such as this is that you could unbalance the control surfaces, which could result in flutter. • If you modify the control surfaces after construction, make sure they are still mass balanced prior to flight. • Fairing over the ends of control surfaces is probably best done during construction and prior to painting so that these changes can be accounted for when mass balancing the surface. Conclusions Wheelpants and intersection fairings made a significant change. Unless you operate your RV from a rough strip, I can’t think of a good reason not to install wheel fairings. Although Van’s makes no specific claim about their tailwheel fairing, my plane gained 1 knot of top speed with it fitted, and it does look better. It’s worth the weight and cost in my opinion. Gap-seal tape was not able to stay attached above 180 KTAS, but might prove useful on a slightly slower aircraft. The fuel drain fairings did not improve the top speed, but they certainly improve the aesthetics. Using a roll of vinyl tape over gaps was cheap and resulted in a 1-knot speed increase, but is not a realistic long-term solution. Taking the time to fair all intersections and reduce gaps between control surfaces may seem onerous during construction, but the cumulative effect of many small improvements can be mea- sured and is much cheaper than trying to add more power. J Nigel Speedy Speedy Nigel Nigel Speedy learned to fly helicopters with the Australian Army and is a graduate of the U.S. Naval Test Pilot School. He currently instructs at the National Test Pilot School in Mojave, California. Nigel enjoys flying his Van’s RV-8 and the freedom of E/A-B to experiment.

KITPLANES March 2018 25 Tricked-Out Tailwheel T3 suspension system eliminates relaunches when touchdowns are a bit too firm. By Paul Dye

Most pilots who have flown tailwheel Unfortunately, the effect of releas- aircraft are familiar with the tailwheel ing that energy by going back to neutral spring—a stinger of springy steel, or accelerates the tailwheel, and spring steel, a set of leaf springs harvested from an being fairly quick, is going to overshoot old car suspension that joins the tail- its neutral position. Then when it gets wheel yoke to the rear of the fuselage. all the way out in the other direction, it For those pilots and builders who never is going to head back—and the process studied physics or engineering, a spring continues. Think about the old Wile by itself is an interesting suspension E. Coyote of Road Runner chase fame. choice: As you compress it, there is what Every time he thought a spring or rubber amounts to energy storage going on. band catapult was a good idea, it wasn’t. When the end of the stroke is released, What is missing in the standard tail- this stored energy wants to escape, and wheel spring is a damper: something to the only way it can do that is by bending dissipate the energy being stored and to back toward its neutral position. So far, slow down the acceleration that comes The original tailwheel spring on the Dream so good…right? We want the tailwheel from a pure spring. In your car, you Tundra was a standard three-leaf spring spring to absorb energy. have springs—but you also have shock with no damping.

26 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes T3 suspensions only come in black, but occasionally Dan Dufault, The basic parts that go into a T3: the central shank, two side plates, creator of the T3, has fun custom painting one like this. mounting brackets, coil-over shocks, and assorted bolts.

absorbers—and that is what keeps models are machined from billet alumi- original tailwheel spring clamps and you from bouncing down the road. In num, and we had to revise our installa- the spring itself. your tailwheel airplane, the effect of tion with a billet aluminum front hinge Our original, factory-supplied con- a pure spring at the back end is to set point when the original steel weldment figuration had a geometry that created up a potential hobbyhorse motion, a began to bend. Overall, as the construc- quite a bit of rake in the tailwheel pivot pitch oscillation that can easily lead to tion has evolved, it has become sturdier axis. This contributed to very heavy a PIO (pilot-induced oscillation) or a and lighter as materials have changed. steering on the ground. The T3 geom- prop strike. So why don’t we use shock etry, using the same Alaskan Bush- absorbers (dampers) on the tailwheel? Installation wheel yoke, stands the steering axis Dan Dufault, founder and creator of We can only talk to installation on the up much more vertically, making the the T3 tailwheel suspension, asked just Tundra, but all in all, it was straight- airplane feel like it has gained power this question, and his answer was simple: forward. We provided T3 with the steering. While this did tend to add a He saw no reason not to give it a try. The dimensions of our three mounting little bit of a shimmy problem on some result is the T3 suspension, sized in vari- points—the single bolt in the center up landings, we have been able to tune the ous configurations to handle airplanes front and the two side bolts in the rear. angle with a wedge—and that made from LSAs up through Super Cubs and The mount came drilled for these loca- the shimmy disappear. on to larger four-seat aircraft. We have tions and bolt sizes. Then it was simply Because it is always going to be hard now flown it on a 180-hp Kitfox and a matter of gaining access to the inside to predict bolt lengths with a new have been using one provided by T3 on of the fuselage (through convenient device like the T3, don’t be surprised our much heavier (2550-pound gross inspection holes) and removing the if you need to lengthen your original weight) Tundra for several months and quite a few landings—both in the backcountry and on pavement. Design The T3 consists of a single or pair (depending on aircraft size and weight) of coil-over shock absorbers and springs. The springs are adjustable for length and tension, and there is a damping control on the shocks. The central tongue is hinged to an anchor bolt at the front, and also bolts to the side plates of the mount. A standard tailwheel yoke mounts to the back of the tongue, and the shocks attach to take up the load. In the case of the early model we received for the Tundra, Installing the T3 on the Tundra started with disconnecting the chains and removing the three all of the pieces were welded steel. Newer bolts that secure the springs to the fuselage.

Photos: Paul Dye and courtesy of Dan Dufault KITPLANES March 2018 27 (Left) The T3, seen here in a top view, attaches using one forward bolt (left) and two bolts on either side in the rear. Because of fuselage curvature, we machined an adapter plate to allow clearance from the T3 side plates and sandwiched it in between. (Right) Fitting the T3 to the three fuselage bolts required putting the fuselage up on a padded sawhorse. bolts and wait for them to show up hardware in various lengths on hand— Flying the T3 from your favorite hardware supplier. that would get a little excessive! Alas, for all of the coolness factor of It’s sort of like opening a present on In addition to adjusting bolt lengths, having those dirt-bike springs and Christmas morning and finding that you’ll probably have to play with tail- shocks hanging out, you’re just not you have to run out and buy batter- wheel chains or links as well. With dif- going to notice much, if anything, while ies, but there really isn’t much of a way ferent geometries, you’ll find more or you’re flying—at least until someone around it. While I like to say I have less sag. But once you get everything set comes alongside and takes some pic- a pretty good stock of AN hardware up the way you like it, you’ll be ready to tures. Takeoff performance is going to in my hangar, I don’t keep AN6 or 7 go try some landings. be similar. Most bush planes we know Dan Dufault, Creator of the T3 We asked Dan Dufault, creator of the T3 Suspension, a few questions facility. I continue to work with Airframes Alaska to custom fit new about how he developed the system and how it is being marketed model aircraft. today. Here are a few of his answers. KP: How many units are out in the field now? KP: What prompted you to design the T3? DD: To date Airframes Alaska and Supercubs North have shipped DD: I was looking for a way to finance a new BMW adventure motorcycle! nearly 400 suspensions to aircraft owners all over the world. Seriously, I had been building STOL planes for the contest in Valdez, KP: How can readers get one? Who is selling them? Alaska, and during the winter of 2015, I realized the importance of hav- DD: Airframes Alaska manufacturers and sells the T3 suspension. ing a suspension not only for the main gear, but the also the tailwheel. Also Aircraft Spruce just announced they are carrying the suspension. Lots of us were welding systems into the fuselage, but no one was So cool—having them carry it is like getting your picture on the cover building a direct-replacement, bolt-on suspension system. of Rolling Stone! We also have dealers like Legend Cub, Kitfox, and I wanted it to be light, durable, and direct replacement. So I built Rocky Mountain Kitplanes. several prototypes and came up with one that I believed would work KP: What models are available? well. I put it on my Experimental Super Cub and began testing it. The DD: Airframes Alaska has a list of suspensions in production. The first flight was so exciting! I taxied around a bit and then took off and list is growing each month. Most any tailwheel aircraft originally made several landings. It felt so different. equipped with leaf springs is adaptable. Soon after those first flights and some tweaking for tailwheel KP: Do you have a price list? alignment and geometry, I was calling some of my bush-pilot DD: Airframes Alaska has the price list on their website. Most friends and asking them to try it. Jay Stanford, Phil Whittmore, single-shock models are $675. The dual-shock super-heavy-duty Jason Sneed, and Mike Creek all provided me with a great deal of version is $875. information and comments. KP: Do you have a list of aircraft they fit without modification? The suspension has evolved several times to its newest version that Or are the installations all a little custom? Airframes Alaska is building. I was so fortunate to have joined efforts DD: Most aircraft equipped with a T3 suspension required no with them. Heather Montgomery, CEO; Abe Harman, mechanical engi- airframe modification. Simply remove the tail leaf springs and install neer; along with the entire Airframes Alaska staff, have been fantastic the T3 suspension. to work with. They are truly a world-class aviation manufacturing —P.D.

28 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes of are off the tailwheel pretty early in the roll, and once it’s airborne, you’re just not going to feel it. It’s on landing that you’re going to notice a difference. I’d describe it best as a “squish” when you touch down on the tailwheel. The shock of touchdown is slowly absorbed, with no tendency to be relaunched if that touchdown is a bit firm. What this means is that you can easily go for the slow, three-pointer, smash the tailwheel down first, then let the mains come down, with little extra worry of the dreaded springy-tailwheel porpoise. If you have flown with low- pressure Tundra-style main gear, you know that you get a nice cushioning effect on touchdown—the T3 gives a The newest version of the T3 installed on a Glasair Sportsman. (Photo: Craig Ellison) similar effect for the tail. has enlisted the power of Airframes the products that will be reliable in the Worth a Try Alaska to produce and market the T3. future as a result. The T3 is fairly new, although there Known for their Alaskan Bushwheels Our current configuration appears to are quite a few already in the field. and many other products and services be stable for our heavy Tundra. I expect Our test unit went through a couple that serve the backcountry pilot, Air- that others are getting good results and of minor mods to make it more rugged frames Alaska is a perfect partner for long life out of theirs, so if you’re looking and reliable, and I expect that this will bringing this new technology to the wid- to trick out your tailwheel, you might continue as more time is accumulated est number of owners and pilots. look into ditching the old-fashioned on the fleet. All new technologies have While we’d all love a fully engineered spring and giving the T3 a test. J bugs here and there, but Dufault seems product that works perfectly and reli- serious about fixing those found by the ably right out of the box, that is not For More information go to the Air- growing number of pilots using the sus- what Experimental aviation is about. frames Alaska website at:http://tinyurl. pension on their own planes. Dufault We put up with a few bugs to enhance com/t3tailwheel.

The red knobs adjust the rate of transfer, allowing a fast or slow rebound. Spring ten- Each T3 is customized for the aircraft on which it will be installed. All T3s are currently for sion can also be adjusted and fine tuned. Experimental use only, but Airframes Alaska has a growing applications list.

KITPLANES March 2018 29 Homebuilt Accidents: Comparing the Rates A true head-to-head comparison with production aircraft is difficult to achieve. By Ron Wanttaja

It seems like homebuilding can’t catch Homebuilt Accident Rate period (1998 through 2015) rather than a break. For this leadoff article, let’s look at how just one year, and using the number of The average U.S. citizen is convinced the E/A-B accident rate compares to the active aircraft as of January 1, 2017. We’re that the Cessnas, Pipers, and Beeches overall GA rate—and to some common shooting for a relative comparison of general aviation (GA) pilots fly are production aircraft types. accident rates, not for any particular year. amazingly hazardous. And, it seems, Computing the accident rates is For the calculation, we need to know many of the pilots of those same GA air- pretty straightforward. Take the num- how many aircraft are actively flying. craft look upon Experimental/Amateur- ber of accidents and divide by the num- This is computed using a combination Built aircraft as death traps. Various ber of active aircraft, and multiply by the of the FAA registration database and reports have claimed that the E/A-B rate average number of hours flown. the FAA’s estimate of what percentage is four to seven times higher than that of However, I’m adding a slight twist. of those aircraft are active. This comes production airplanes. The usual method uses the number of from the annual FAA General Aviation But—is it really that bad? How pre- accidents in a year and the number of Survey, which also provides an estimate cise are the estimates? What are the aircraft registered in that year. of the average annual flying time. factors that drive our rates higher than The problem is that the number of With this data, we can now com- production aircraft? What are the major accidents can vary significantly from pute the accidents per 100,000 hours causes in accidents affecting specific year to year. Thus the results vary, mak- of flight. Figure 1 shows the results, homebuilt types? ing it harder to draw conclusions. and it’s not pretty. Using this method, In the next several months, we’re going Instead, my analysis uses the aver- the homebuilt accident rate is about 2.5 to take an in-depth look at these issues. age number of accidents over an 18-year times that of the overall rate, and four

30 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes times higher than common GA aircraft like the Cessna 172. All is not lost, however. There are some problems with the data commonly used as input to this analysis. Non-Homebuilt Accidents Counted as Homebuilts How many homebuilts have crashed? A lot fewer than the NTSB database will lead you to believe. Their database includes a flag labeled “Homebuilt.” The online implementa- tion of this is a pull-down selection labeled, “Amateur-Built.” The problem is, the flag is unreliable as far as indicating the certification status of accident airplanes. Certi- fied Light Sport Aircraft, unregistered Figure 1: Accident rates using traditional methods. ultralights, Experimental Exhibition airshow aircraft, and even Boeing airlin- that shows each aircraft’s certification in homebuilts, but are not included in any ers are incorrectly tagged as Amateur- a series of numbers and letters. The first counts of E/A-B aircraft. Built. Foreign-registered homebuilts are number shows the overall certification I have a friend who completed an there, too, but they weren’t necessarily category of the aircraft: “1” for Standard, RV-6 back in the ’80s. His plane has built to U.S. E/A-B rules. “2” for Limited, “3” for Restricted, “4” been flying for almost 30 years, yet it Figure 2 illustrates this issue using for Special, and so on. Additional char- has a blank under “Airworthiness” and NTSB data from 2014. Out of 225 acters are added to show sub-categories isn’t counted as a homebuilt. The plane aircraft tagged as “Homebuilt” in the within the overall ones. For instance, is also in the NTSB database for a minor NTSB database, 47 weren’t U.S.-certi- homebuilts are recorded as “42”…“4” accident. So it counts as a homebuilt for fied Amateur-Built aircraft. for Special and “2” for Experimental/ accident purposes, but isn’t included in Works both ways, of course. Seven Amateur-Built. the overall fleet size computation. aircraft in 2014were homebuilts, but Simple enough, really. Count the num- Aren’t there other types of planes in not identified as such. ber of cases where “42” appears in the col- the “phantom” list? Sure! But no one umn, and you should have the number of counts the number of Cessnas or Pipers “Phantom” Homebuilts Experimental/Amateur-Built aircraft. by airworthiness type. How do we know how many homebuilts But more than 25,000 aircraft regis- These “phantom” homebuilts should there are? The FAA registration data- tered in the U.S. don’t have an entry in be included when determining the over- base has an “Airworthiness” column this column. More than 6000 are obvious all fleet size. As shown in Figure 3, that

Figure 2: Almost a quarter of the “homebuilt” accidents in Figure 3: Almost 25% of the homebuilts in the U.S. are not counted. 2014 were not Experimental/Amateur-Built Aircraft. This inflates the E/A-B accident rate.

Photos: Ron Wanttaja and Paul Dye KITPLANES March 2018 31 This RV-6 was given an airworthiness certificate nearly 30 years ago, but FAA records do not list it as an Experimental/Amateur-Built aircraft. means that the total number of active Every year, the FAA sends out ques- single-engine piston airplanes are homebuilts is almost 25% higher than tionnaires to a subset of registered business/instruction/commercial fly- the “official” tally. aircraft owners and generates a set of ing, compared to just 13% of the E/A-B estimates of various use factors. The cat- hours. A fair comparison would pit the The Problem with egories are broad; there’s a single-engine homebuilts against production aircraft Flight Time Estimates reciprocating category and one for flown solely for recreation—but there’s If we’re comparing accident rates on the Experimental/Amateur-Built. no way to do this. A man who flies a basis of flight hours, we need an esti- The 2015 Survey said that homebuilts 172 for recreational use, then sells it and mate of the annual flight time for each fly about 47 hours a year. The estimate buys a Van’s RV-7, is not likely to fly half type of aircraft. As mentioned, this data for the piston-powered single-engine as much. Yet that’s the conclusion one is included in the annual FAA General fleet is almost twice that, about 87 draws from the FAA Survey data. Aviation Survey. hours per year. Type of use affects the results in Right there is where most of the other ways, too. A commercially flown “high homebuilt accident rate” story aircraft is inspected more often (both Do You Own is coming from. Even if the number of annual and 100-hour inspections), accidents is close to that of production and a privately operated aircraft may a “Phantom” airplanes, the lower hours estimate for be exposed to more non-professional homebuilts will produce an hourly acci- (i.e., owner) maintenance. In addition, Homebuilt? dent rate twice as high. inactivity is hard on aircraft engines; a As mentioned in the main article, roughly But according to the FAA Survey, trainer that flies 200 hours per month 25% of the Experimental/Amateur-Built the majority of the hours (55%) for will probably show fewer problems aircraft in the U.S. aren’t recognized as such in official FAA records. This is especially a factor when the accident rate is computed. How can you tell if your homebuilt is “phantom”? Go to www.faa.gov, and enter your N-Number in the “Look Up N-Number” block. You’ll see the registration entry for your airplane. Under “Airworthiness,” look at the “Classification” and “Category” blocks. They should say, “Experimental” and “Amateur-Built,” respectively. If they say “Unknown” or “None,” you’ve got a phantom homebuilt. Note that it doesn’t affect the legality of your aircraft. It’s a paperwork glitch at the FAA; as long as you have an airworthiness certificate, your airplane is legal. —R.W. Figure 4: Average annual fleet accident rate.

32 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes If one believes the FAA survey results, the owner of this Lancair IV flies only half as much as the owner of a Cessna 210. (Photo: Courtesy of Lancair International) than a five-hours-per-month Starduster Reality maintained, and often designed by ama- or Aeronca Champ. The same holds for In reality, the actual accident rate is teurs. A higher accident rate is inescap- pilots, as well. going to fall somewhere between the able. About 6% of homebuilt accidents The issue is comparing comparable 12% and 45% of the overall GA rate. involve first flights, and 20% of them use, and the FAA Survey results just More of the “phantom” homebuilts occur during the first 40 hours—obvi- don’t provide a reliable answer. are probably inactive—though a far ously a hazard that’s not a factor with lower number now, when the owners production-type airplanes. The Fleet Annual Accident Rate have to renew their registration every In our next installment, we’ll do a What happens when we ignore the three years. head-to-head comparison of accident annual flight time estimates? We can cal- Even so, this isn’t probably so bad. causes between homebuilts and general culate the average annual “fleet accident Homebuilt aircraft are built, flown, aviation aircraft.J rate” from the rest of the data. This is the percentage of the number of aircraft of a given type that have an accident during a given year, irrespective of their use. It’s a simple computation, using just the number of aircraft (corrected by the “active aircraft” percentage of the GA Survey results) vs. the number of accidents. Again, let’s use the average number of accidents over an 18-year period (1998 through 2015). We’ll divide it by the number of aircraft registered as of December 31, 2015. Figure 4 shows the result for both homebuilts and several common production aircraft types. The overall U.S. rate, using the raw FAA and NTSB data, is about 0.81%, compared to 1.17% for homebuilts—about 45% higher. But as discussed earlier, there are problems with both the FAA registration data and the number of E/A-B accidents per the NTSB. If we include only actual E/A-B accidents as discussed earlier, and include the “phantom” homebuilts, the homebuilt fleet rate drops to 0.90%. That’s just 12% higher than average, and actually less than some production types.

KITPLANES March 2018 33 Under New Management

An inside look at EFII’s all-new electronic engine control system for Experimental Lycomings. By Tom Wilson

As first reported in Newsline on the systems are scheduled for sale in April to install, and far easier to upgrade than KITPLANES® website (https://tinyurl. 2018, with install kits available now. the legacy unit. It also offers EFII total com/EFII32), California-based EFII Beginning in 2007, EFII sold a basic control over manufacturing. debuted an all-new electronic engine electronic engine management system. Called System32 after its 32-bit RISC management system for Experimental Assembling ignition and fuel system processor, EFII says the new system has Lycoming-based engines last September. components from the aftermarket, Can- at least 50 times the processing power Shown at the National Championship ada-based SDS, as well as their own sup- of EFII’s previous system. The extra Air Races in Reno, Nevada, the new porting hardware, the legacy EFII system capability comes from the more mod- hardware and software is a major advance has been fitted to over 400 aircraft. ern processor, a unit that also offers in engine management sophistication But now Robert Paisley, owner of the channels and processing power and tunability for our kind of airplanes. EFII, has delivered an entirely new digital to optionally control boost pressure, As we went to press, ignition-only ver- engine management system that is 100% ADI flow, up to three oxygen sensors, sions of the new system were expected designed and manufactured by EFII. It is TECAT torque sensing, and real-time to be released in January 2018. Full much more capable and accurate, easier telemetry. System32 does not control

34 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes (Left) Robert Paisley checks the function of a System32 ECU on its dedicated test stand. (Right) Like the rest of the system, the all-new System32 ECU was designed and is built by EFII. Paisley noted when asked about the circuit board, “We’re lucky to live near LA, one of the world’s technology centers,” where the board is built by specialists. Likewise, the ECU’s software was developed by Paisley and two consulting engineers he’s worked with for years. constant-speed propellers, but it can This last feature will likely be rarely also includes ignition timing retards for operate up to 12-cylinder engines. needed by average users, but does give excessive over-square engine operation The optional capability is great for instant adaptability to each specific the previous system did not have. tinkerers, racers, and development engi- installation, special conditions, or neers, but for average Joes, System32’s equipment changes such as an engine System Description brainpower is put to most practical use overhaul, cold air intake, and so on. Before moving into aviation Paisley by running its 3-dimensional rather Furthermore, this adjustment knob earned an electrical engineering degree than the old 2D fuel and spark maps. In has tremendous authority, much as a and had a long, successful run building other words, the data points System32 manual mixture control does. EFII’s electronic ignitions and other controls uses to select the fuel and spark events legacy engine management had a similar for a broad array of ground vehicles. are more nuanced for easier starting feature that allowed -50 to +50% values, There was an emphasis on motorcycles, over a wider range of environmental and and Paisley is doing the same with Sys- including drag race bikes, a discipline engine conditions, plus smoother run- tem32. Besides offering deep tuning, the he competed in personally. Along the ning and transitions such as quickly add- big adjustment range is a hedge should way he realized engine management ing throttle for takeoff, climb, or acro. a sensor go bad and result in dramati- systems should have all necessary capa- Naturally, System32 employs a fully cally rich or lean mixtures. In that case bilities, but always with simplicity and redundant dual ECU layout, so if one the pilot could simply turn the knob and computer fails, the other can take over restore a running mixture to the engine. by flipping a switch. Just as basically, Sys- Speaking of a wide dynamic range, tem32 eliminates the mixture control in System32 software is written to support the cockpit. The software automatically everything from fuel misers to rip-snort- chooses the best air/fuel ratio for the ing race systems. If you bolt twin tur- amount of air the engine is ingesting, plus bos onto your O-290 GPU conversion, there is a fuel trim knob that further trims System32 won’t need reprogramming the fuel delivery should the pilot so desire. to keep up. Its increased sophistication

One end of the ECU contains the SD card slot and four LED annunciator lamps, so access to this side of the ECU is desirable as mounted in the airframe. This is especially so in ignition-only installations as this card slot is the only access to the system. In full Connector plug-ins are all located on one edge of the fuel-and-spark installations, the cockpit System32 ECU box. With no directional requirement by the ECU, display offers an SD card slot that makes the blue boxes can be installed in any convenient orientation in the airplane. these on the ECUs redundant.

Photos: Tom Wilson KITPLANES March 2018 35 That’s a Garmin G5 at left and the new System32 display at right. The System32 uses the Designed to fit in a standard 13 /8-inch identical screen as the Garmin, so the days of apologetic, science-fair-quality engine instrument panel opening, the System32 management interfaces has been replaced by a modern display that blends perfectly display takes up little panel room, either with other Garmin electronics. The SD card slot on the System32 display is front and in front or back. center for easy access; all system upgrades can be done through this slot. robustness in mind. It’s fairly easy to quit, and you’ll definitely notice that! than fuel, plus the engine is trying to over-feature electronics, adding com- Simply switching to the other ECU accelerate under a load. Without the plication and failure points in exchange using a switch on the instrument extra shot of go juice, the engine would for gee-whiz features of questionable panel restores injector function so the momentarily lean out. usefulness. The fewer gizmos in the flight can continue to an airport on The System32 engine temperature loop, the fewer gizmos there are to fail. one ignition system. sensor is there to identify a cold engine, Applied to System32, this means As for the throttle position and and thus a little extra fuel for sufficient it’s a competent engine manager, but engine temperature sensors, the TPS atomization and smooth running is one working within the realities of simply identifies rapid throttle openings needed. With System32 the temp sen- Lycoming engines and not concerned to act as an electronic accelerator pump. sor screws into the 1/8-inch pipe threads with anything more than unfailingly That is, a little extra fuel is needed where the mechanical fuel injector noz- getting the right amount of fuel and immediately when the throttle is enthu- zles would otherwise be. There is only spark into the combustion chamber siastically opened because air is lighter one engine temp sensor per installation. at the right time. Thus, System32 is a batch-fire (all injectors fire simultane- ously), speed density design (no mass air sensor). It uses two identical computers (Engine Control Units), two crankshaft triggers, two intake air temperature (IAT) sensors, two manifold absolute pressure (MAP) sensors, a throttle position sensor (TPS) and an engine temperature sensor. Two ignition coil packs are used, each controlled by one of the two computers. The only major single- point in the system is the fuel injectors; there is one injector per cylinder, and all injectors are fired by one of the ECUs. So configured, should the ECU not EFII supplied us with two screens the System32 display can show. Most of this is self- operating the injectors fail, the result explanatory, and there’s plenty more information not shown here, but the vertical scale will be one-half of the spark plugs will with yellow and green bands is especially nifty. It is the air/fuel ratio display with the quit firing—an almost imperceptible red bug identifying the current A/F ratio and the green and yellow bands denoting the condition given the powerful induc- ideal and usable ranges of A/F ratio, which the pilot can dial-in via the display’s knob in real time. These ranges vary depending on engine load. Other red bugs show which tive ignition. If the failed ECU was ECU is controlling fuel delivery—spark duties are always split between both ECUs. There operating the injectors, then all the are some engine monitor values shown here, but a complete engine geek would still injectors and half the spark plugs will enjoy a multi-probe EGT/CHT monitor for pinpointing errant cylinders.

36 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Wanting a much sturdier and more accurately One goal of the new crank trigger mount was to present the crank triggers to the mounted crank trigger, EFII whittles out this billet Lycoming flywheel in a curve conforming to the flywheel as shown. This fits the triggers aluminum dual trigger and mount for Lycoming closer to the flywheel and allows a more precise trigger signal. Because System32 does cases and flywheels. Both triggers are located not use a camshaft position sensor (less cost, no real mounting place on a Lycoming) under the dark strip in the center of the sensor. or multi-point flywheel magnets, the system does not support hand propping. A more major System32 evolution rpm for fuel or spark value look-up. This own manifold pressure curve. This is the over the legacy system is in the soft- simplified mapping was forced by the essence of 3D mapping and is similar to ware. Both systems are simple look-up limitations of the 8-bit microprocessor how any modern car computer functions. designs, where information comes in to of the legacy ECU. This is why System32 is based around the ECU, which then plugs those values In System32 the fuel and spark tables the entirely new high-speed processor. into either a fuel table or spark table to have a full range of rpm and manifold Of course, there are complicating arrive at the amount of fuel and spark pressure points mapped, and as the details, but not many. When you think timing to command. The difference is manifold pressure changes with throttle about it, the ECU is inferring the air in the tables. In the legacy system there position and altitude, there are corre- mass entering the engine because it is a simplified scheme that applies the sponding changes in the fuel and spark knows the engine displacement, how same manifold pressure curve to every delivery. Essentially, every rpm has its fast the engine is operating, and what Open Philosophy Engine management makers subscribe to one of two philosophies that are super- or turbocharged typically receive minimal boost. when it comes to customer access to software: either sequester it from This keeps cylinder pressures relatively low, thus preserving a useful the customer or give them full access. Most manufacturers and their detonation margin. Truly supercharged engines—think 45 inches of lawyers figure engine tuning is too complex, too poorly understood, manifold pressure and climbing—with elevated cylinder pressures and too potentially dangerous to the engines being controlled to are far more on the edge. Where an NA or turbonormalized engine may give the simpletons buying the stuff any ability to alter the software nibble into light detonation without damage, a boosted engine races controlling fuel and spark delivery. to destruction. Think of the difference between lighting a log with a Other makers believe most of their customers combine enough match versus a pan of gasoline. native intelligence, engine tuning, and computer experience, along Another big safety factor is 100LL fuel. It boasts a high anti-knock with a healthy conservatism when it comes to tuning their engines to index and plays a big part in the relatively high detonation margin avoid dramatic outcomes. enjoyed by today’s typical aircraft engines. Hopefully whatever even- Robert Paisley is of the second mindset and therefore has made tually replaces 100LL is just as knock resistant. System32 software an open book to the consumer. The “tune” can Thirdly, aircraft engines are expensive. Even aggressive hot be downloaded via the SD card slots to a computer, then opened and rodders don’t enjoy the time and money wasted changing cylinders manipulated in Excel software. Tunes can also be shared among users; and pistons should they “rattle” the engine. That keeps wild thinking EFII can easily send updated software to customers. just thinking. Honestly, after decades of watching auto enthusiasts scatter V-8s And finally, when an aircraft engine cracks a cylinder just below the with overly aggressive or ignorant tunes, this seems generous to us as head or, better yet, blows it off the engine case, the guy in the plane is there are truly dangerous pitfalls (detonation) when monkeying with in for a bad day and none of us wants to be that guy. And that’s what engine management tunes. keeps most of us from turning the knobs too far or tinkering with what That said, there are some guardian angels watching aviation tuners. we don’t fully understand For starters, most aircraft engines are naturally aspirated, and those —T.W.

KITPLANES March 2018 37 Stronger harness connectors were on the System32 wish list, and these round bulkhead Worth It? fittings—one for fuel, one for ignition—fill the bill nicely. The side with the square flange fits behind the firewall, leaving a clean round plug on the engine side. By now the pluses and minuses of electronic engine control over two magnetos and a car- the manifold pressure is. But it is bet- fixed-pitch propellers where it’s possible buretor—and to a lesser extent mechanical ter to further refine this inference by to run the engine over square—more fuel injection—are fairly well known, but it’s knowing what the intake air tempera- manifold pressure than rpm—during a list always worth reviewing. ture is (correcting for density altitude, takeoff or full-throttle climbs. “With Much easier cold and hot (especially) you might say). Thus the IAT sensor System32 we have a different manifold starting is a digital engine management is added. The computer uses the IAT pressure retard curve for every rpm plus, as is smoother idling and greatly signal as a correction factor, modifying point,” says Paisley. “If you start get- reduced pilot workload (no need to jockey the fuel injector duty cycle by whatever ting over square, System32 retards the the mixture control). With a computer con- percentage the IAT table says to. This ignition timing to avoid detonation. At stantly managing the air/fuel mixture, the correction is fairly small, so much so the 2700 rpm you can bring in the ignition average pilot could see some fuel economy engine would run without it; but it runs timing more aggressively because you benefits, but it’s the advanced ignition better with it. won’t run over square. At 2350 rpm for timing at altitude that really saves the gas. Practically speaking, the increased example, we can retard the timing if the Much depends on where and how you fly, attention to manifold pressure in Sys- engine enters an over-square condition, but EFII figures on burning 1 gph less on tem32 software reduces engine load and we can prevent detonation. This is a 4-cylinders and 1.5 gph less with sixes. (mainly by retarding the ignition tim- problem that can occur with fixed-pitch Altitude is also where the largest power ing) in dangerous corners of the engine’s props in climb or with constant-speed gains are made, with sea level takeoff operating range. This shows most with props when descending. This is already power typically gaining little, as in not enough to feel. That’s because low-altitude power is where traditional magnetos and carbs are tuned for. There are no magnetos, carburetors, or fuel servos to overhaul, and the automotive spark plugs are far less expensive and make more sense to replace than spend time cleaning. As for initial cost, yes, it makes little fiscal sense to replace good-running, mid-time magnetos or mechanical fuel injection, but if it’s time for magneto overhaul, stepping up to e-management is a big step closer. And if you’re building a new airplane, digital engine control can cost less than obtaining conventional systems. This is especially true if the airframe already sports the required robust electrical and grounding systems System32 uses new wiring that’s more robust and user friendly than before. The three demanded by e-engine management and System32 harnesses are built by EFII at their Cable Airport (KCCB) facility in Upland, glass instrument panels. California, using unique, mistake-proof terminal ends, Tefzel insulated wire, and round, —T.W. multi-pin bulkhead fittings.

38 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes All System32 fuel injector and ignition wires are fitted with fusible Yes, those are computer industry DB connectors, and they are links to protect the other injectors or coils in the harness. Here a in the System32 harness to provide back compatibility with the harness has been cut open to reveal one of the small green fusible legacy EFII management system. They transmit various sensor links. Because it’s at the end of the harness on the engine side of data and will likely be replaced by circular connectors once the firewall, it is easy enough to replace a blown fusible link once all beta testing is complete and the market for legacy system the cause has been rectified. upgrades has been fulfilled. in the software and is one of the main oxygen sensor input to further refine to protect. Yet EFII has accommodated benefits of 3D mapping.” the amount of fuel delivered, a neces- oxygen sensors in its systems, including Finally, there is a “return-to-base” sary step to protect the finicky catalytic System32, but strictly for pilot informa- mode for the rare chance both MAP sen- converters that can only operate in a tion. With oxygen sensors the air/fuel sors, or a combination of other casualties, narrow air/fuel mixture range. Such ratio can be shown on the cockpit display, occur. Then the software would rely on post-combustion information requires so the pilot has an immediate view of the an electronic barometric pressure sensor more computations by the computer, as air/fuel ratio being supplied, rather then in the ECU and the TPS signal to nicely you may imagine. inferring it from EGT readings. But it’s approximate a workable fuel volume. This operating mode is calledclosed worth noting the oxygen sensor input is loop, as opposed to open loop, where the simply passed to the cockpit display and Flying Open Loop oxygen sensor input is ignored (during doesn’t modify fuel delivery. The car that takes you to the airport has cold starts before the cats have warmed Finally, EFII is not a dealer for, and oxygen sensors sniffing the percent of up, for example) or in a system where does not carry, oxygen sensors. Instead, oxygen in the exhaust stream to accu- there are no oxygen sensors. they recommend purchasing “ox” sen- rately assess the actual air/fuel ratio the System32 is open loop by design sors from PLX Devices. This eliminates engine is operating at. The ECU uses because there are no catalytic converters the price markup necessary should EFII

(Left) EFII is using the same Bosch fuel injectors as in their legacy management system but has developed this new, more compact fuel rail arrangement. (Right) Key to the new fuel injector installation is the injectors have been moved from the intake tube and into the Lycoming cylinder’s primer port. This saves having to weld bungs onto the intake runners and gives a straighter shot of fuel toward the cylinder. It’s also more compact packaging on the engine.

KITPLANES March 2018 39 These representatives of the ignition side of System32 have changed little since the legacy Robert Paisley and Lylah Bradford are EFII. system. They are a two-coil coil pack, automotive style NGK Iridium spark plug with brass Robert is the technical guru while Lylah adapter, MAP sensors, and the ignition leads. Two coil packs are required; EFII fits them is key to production. If you have an EFII with a flat aluminum mounting plate to aid installation under the cowling. wiring harness—among many other EFII parts—Lylah built it. be a PLX Devices dealer, along with that keeping the ECUs separate allows the associated shipping, stocking, and easier troubleshooting. If an ECU is sus- wiring, Paisley expects most customers financing headaches. EFII maintains pected, it is easy to disconnect or replace will update to the new wiring harness to the same relationship with Andair for it, something not so easy to do if both gain the new bulkhead connectors and fuel valves, too. computers share one box. built-in fusible link protection among The cockpit controller is especially full other things. The New Hardware of promise thanks to a screen identical System32 is priced identically to the System32 is built around five new major to Garmin hardware and ultra-easy sys- legacy system, at least initially. That components: the ECU, cockpit control- tem initial setup and in-flight trimming older system has ceased production, but ler, wiring harness, crank trigger, and of ignition timing or fuel mixture. Tak- will “absolutely” be supported by EFII. fuel injector mounting. ing up very little space fore-and-aft in a System32 is offered only as a dual Each System32 uses two of the blue standard 31/8-inch round panel opening, ECU system, so there are two blue boxes ECU boxes. Both ECUs could be the shallow new controller displays alarm per System32 installation, and it’s a com- housed in a single box, but Paisley notes and annunciator functions for ECU plete kit. All sensors, wiring, injectors, power, fuel pump power, two battery and their plumbing, coil packs, ignition voltages, plus an air/fuel ratio graphic dis- harness, spark plugs, cockpit controller, You Are A Tuner. play, and offers easy updateability via an crank trigger, and associated mounts SD card port. Access to the entire system and hardware are included. Pricing for a Really. is thus immediately in front of the pilot, complete fuel and spark 4-cylinder Sys- One major innovation of System32 is its and should upgrades be necessary, they’re tem32 is $6,195. A 6-cylinder complete simple initial setup. Before the system’s equally accessible via the SD card reader. system is $7,695. first operation, the installer is prompted Because the System32 components The ignition-only derivative of Sys- to enter the engine’s displacement and plug into existing EFII wiring harnesses, tem32 is available at $2,750 for the compression ratio. These two factors customers already running EFII’s legacy 4-cyl ignition and $3,395 for the 6-cyl determine the engine’s horsepower, at system can update to System32 without ignition. Like the complete systems, the least to the first magnitude, and thus tell rewiring their airframes if desired. This ignitions are 2-box ECU installations. System32 what it is managing. The engine backwards compatibility is also giv- Finally, we’ll close by noting as with will then run well enough to fly, and if finer ing EFII the needed beta testing of the any digital engine management system, tuning is needed, this is both easily seen new ECU. The new ECU will first fly the airframe it’s going into must be and accomplished via the cockpit display. by replacing the existing ECU on EFII electrically sound. The ground circuit, Much more advanced tuning is possible legacy systems, followed by the new dis- battery(ies) and charging system(s), and with System32, but this simple setup is all play, injectors, and so on. bus design must be top notch because as most normal installations will likely need. While existing EFII customers could with all electronics, System32 depends —T.W. install System32 using their existing on a steady flow of electrons.J

40 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Book Review Pioneer Mechanics in Aviation Giacinta Bradley Koontz looks at the history of early and notable A&P mechanics. By Bob Hadley When non-flying friendsask me what My research led me to a Harriet Qui- your plane has a Sensenich propeller, books I’ve read lately, I mention Pioneer mby website and book by aviation writer for example, or a Pratt & Whitney Mechanics in Aviation. I always get a and historian Giacinta Bradley Koontz. engine, you’ll probably jump right to double take with that answer because In addition to the Quimby book, she those chapters. most people expect Harry Potter, Twi- had just completed two other books: The Each of the 20-some pioneer mechan- light, or some other pop culture book du Original Grand Canyon Airport and, the ics featured by Koontz has an amazing jour. But if you know me and my EAA subject of my review, Pioneer Mechanics story, and she does justice to all. The mates at Chapter 494, Pioneer Mechan- in Aviation. The topics looked interest- reader will discover what these indi- ics in Aviation is our cup of tea any day. ing, so I bought all three. When they viduals did to attain their status and the I discovered this book by accident. arrived I was pleasantly surprised to find enduring family connections that persist A while back, I was looking up info on them autographed and personalized! to this day. The book also talks about the America’s original aviation sweetheart Koontz’s bio is really interesting. Portal of the Folded Wings Shrine to (before Amelia), Harriet Quimby. Har- She’s been an aviation writer a long Aviation in Burbank, California. More riet was the first American woman to time, but I had never heard of her than a dozen historic figures of avia- earn a pilot’s license, a feat for which she because she has mostly written for tion are buried there, including Wright was deservedly honored on a U.S. post- trade journals such as Aircraft Main- brothers’ mechanic Charles Taylor and age stamp in 1991. I was going through tenance Technician and Director of Winfield Bertrum “Bert” Kinner, two my wife’s stamp collection looking for Maintenance. Her columns generally of the featured inventor/mechanics pro- aviation-themed stamps when I saw the focused on notable, but largely unsung, filed in the book. Harriet Quimby stamp. “Hey! That’s the heroes of early aviation including many Pioneer Mechanics in Aviation deserves same last name as Roger (my neighbor).” pioneer-era mechanics, of which many to be in every collection of aviation I asked Roger if he’d ever heard of her eventually became important boom- books (as do the other Koontz books). and he said, “According to family lore, era engineers and designers. Pioneer As for the Quimby family history? we might be related.” But, he conceded, Mechanics in Aviation is a compilation Roger’s still not sure. Harriet Quimby no one knew for sure. of some of Giacinta’s previously pub- died in 1912 at age 37 after falling out I had to find out! How exciting lished articles. of her Blériot monoplane. She was never would that be? To live across the street The book is organized with every married and had no children. So if he’s from a direct descendant of a bona-fide profile as a chapter, so you don’t have related, it’s by way of some other branch aviation pioneer! to read it in any particular order. If of the family. J

KITPLANES March 2018 41 The Heart Spars of the Wing

Part 2: Laying out the spar. By Paul Dye

We’re looking at spars, the heart of our get, with a built-up metal spar, ribs, and fasteners (bolts and Clecoes) and the wings. In our last installment, we took skin. Yes, the Xenos wing is much lon- actual final assembly. This month, we’ll a look at them theoretically, describing ger than most, but that is just a matter of go over the process of fitting together the the various parts and how they work design scaling. It is not aerobatic, but the components and drilling all holes in their together to provide the primary load- length of the spar makes the root section proper locations and to final size. The carrying member of the wing, reacting fairly hefty—heavier, in fact, than many Xenos spar can be bought as a kit, you to loads in the direction of the lift vec- short-winged aerobatic spars. can (theoretically) build it from plans, or tor. This month, we’ll begin to construct Building a metal spar can be broken you can buy a completed set of spars from the spar for a Xenos motorglider. It’s an into two parts: assembling and drilling Sonex LLC for an extra $4,000. That all-metal wing that is as typical as they all of the components using temporary sounds like a lot of money, and it is—but

42 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes in this section are part of the spar, with The Heart the ribs being attached as lap joints later on in the build process. There are seven pairs of these little flanges on each spar of the Wing (one fore and one aft in each pair), and they are mostly unique to their station, so you have to label things and make sure they go in the right place. Keep a bunch of Sharpies on the workbench and use them liberally to label parts. Mark things “fore,” “aft,” “inboard,” and “outboard.” Oh—you’ll be drilling some holes now, others later, and some to different

The wingspan of the Xenos all-metal wing is just over 39 feet. (Photo: Courtesy of Sonex Aircraft) sizes, so label liberally. Acetone will take all the markings off when you’re done. I would bet that unless you build a few to tip, making for some very complex I also like to keep blue painter’s tape of them, the number of hours you’ll put shapes. The webs actually get in the way handy to cover prepunched holes that in will surprise you. You might find that during much of the build because of are not to be up-drilled until later. you’re working for a couple of bucks an their shape, and we found that it was far It really helps to have a workbench hour. But building is what we’re about, easier to assemble as much of the web as long enough to lay the spar out from end and the accomplishment you feel when possible and insert the caps for drilling to end, with no overhang on the ends or you’re done is significant! near the end of the stack-up. sides. Having room to lay out parts par- Because of the thick web near the allel is important, too, so having a table What’s Included? root, and considering that many build- wide enough to do this will really keep The kit parts include extruded and ers buy spars that are completed and things organized. With spars about 25 shaped top and bottom cap sec- don’t have the tools to drive -5 (5/32- feet long, this makes for a pretty big tions, a large roll of web material (all inch) rivets, the flanges that attach ribs table! We actually extended our big prepunched), some thick spar web sections (precut and prepunched), and a number of components you have to build from extruded aluminum angle and some sheet metal. Building any Sonex aircraft requires that you fabricate a lot of parts required for major assemblies, and I find it quite satisfying to make the clips, brackets, and other small bits from the drawings. We’ll start the assembly process here with all of the small components already built, which still leaves a huge amount of fabrication to be done during assembly. The roll of spar web material consists of 6061 T-6 sheets, all cut to approximately 6 inches wide and varying in length. The thick spar web sections are used near the root end and stack up to create a web approximately ¾ inch thick. The cap extrusions are roughly “T” shaped, with the leg of the “T” to be inserted in slots made up of stacking the web sections. The top of the “T” actually slopes down Liberal use of Sharpies ensured that correct flanges (in this case, ones labeled “J”) were on the upper spar cap (or up on the lower placed and attached at the correct sites. Marking and covering some areas with blue cap) toward the center of the wing. The painter’s tape made sure that holes weren’t up-drilled prematurely and that the correct caps also taper continuously from root drill bit was used.

Photos: Paul Dye KITPLANES March 2018 43 Frequent and repeated consultation with the drawings proved necessary to ensure proper stacking of the various web layers. As the right and left sides were notably different, builders also have to make sure they consult the correct drawings. workbench using some old wooden doors with 2x4-inch framing to create supports. Having a surface that you can drill and Cleco straight into makes things easier, as well. Parts Puzzle The drawings for the spar show a schematic of the various web layers. It took a bit of noodling to figure out the jigsaw puzzle, but the prepunched parts gave us lots of clues. If the holes don’t line up, it’s wrong—but don’t let that lull you into complacency, because if they do line up, that doesn’t make it a slam dunk that you’ve got it right. Many hole

Building or combining workbenches at Out beyond mid span on the spar, the web the same height that extend at least as decreases to only a single layer of sheet long as the wings greatly facilitates the metal and layers sit on one side or the tasks. The ability to work from both sides other of the “T” spar cap (bronze colored). of the bench also minimizes the need to That side changes as you continue to go “swap ends” while work continues. outboard, as shown in this photo.

44 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes As assembly of the wings approaches the root, wing nut Clecoes The -5 rivet holes were clamped by 4x25-millimeter (1-inch) bolts, begin to replace standard spring Clecoes. washers, and nuts. patterns repeat at various points in the go outboard. Learning how to read draw- too thick for spring-loaded Clecoes. You assembly. We also found that even after ings is vitally important here—espe- can use them as alignment aids, but they completing the left spar, getting the cially understanding hidden (dashed) won’t hold things together. The next right spar assembled was still a think- lines so that you know what is in front step up from a spring Cleco is a wing ing person’s game because the layups are and what is in back. Never assume you nut Cleco. They have a long reach and not symmetrical left to right. In fact, have it right in one glance; look again get screwed down without the use of pli- the right spar is built somewhat back- and again. Spar building is a place to ers. Unfortunately, they also cost about wards to the left! keep the tools in the drawer while you $3.50 each, and you’ll need lots of them. Once you have the layers stacked up, lay things out—for a long time. This is the time to make friends with a if you look at the end of the root end of long-time sheet metal builder and see if the web, you’ll see a groove between lay- Drill Time they have some you can borrow. Forget ers that will hold the leg of the spar cap Once you are confident that you have about -3 (3/32-inch) wing nut Clecoes; “T.” This is very obvious at the root end the layers in place, it is time to drill a spend your time and money on a few -4 with its many layers, but once you get few holes—just a few—to pin things (1/8-inch) units. out beyond mid-span on the spar, you’ll together. If you have previously built In the Xenos spar, almost all rivet find that the web has decreased to only a sheet metal parts, you probably have holes will end up as -5. Because many single layer of sheet metal—so the layer hundreds of Clecoes at your disposal. of the holes are very close to the caps or sits on one side or the other of the “T.” Unfortunately, none of them will help other components, even wing nut Cle- And that side changes as you continue to you at the root end because the section is coes aren’t going to help; their bodies are

(Left) Match drilling the rib attach clips must be done from both sides of the spar. (Right) Inexpensive bookshelf brackets were attached to the workbench to hold and stabilize the spar in a vertical position while the rib attach clips were match drilled.

KITPLANES March 2018 45 Sonex provides a few drill jigs that Cleco onto the rib attachment holes too big. In this case, we went to plan B, in the outboard two-thirds of the which turned out to take a little more spar. We found it helpful to make time, but saved us a whole lot of money! many more for the job. It turns out that a -5 rivet fits in a hole drilled with a #21 bit. And that exactly fits a 4-millimeter-diameter bolt. So, we bought a box of 4x25-millimeter (1-inch) bolts, washers, and nuts. It might sound excruciatingly time con- suming to install and remove all those nuts and bolts, but honestly, it just doesn’t take more than a few extra hours—and you’ll be spending hundreds of hours on the spars. We don’t know how the pros do it, but this sure works for those of us that aren’t going to do this more than a couple of times. Anyway, with the spar web layers in place, we started drilling holes: first enlarging the prepunches to #40 and installing silver Clecoes to hold things in alignment, and then going up to #21 and installing our 4-millimeter bolts and nuts. We left all of the holes that would take other parts—the clips for the ribs, the large blocks for the main wing-mounting bolts, and the holes for spar caps—in their original state. It’s far more precise to leave them this way and drill them when you are ready than to have small and large holes in a stack-up. Once the main web portions were bolted together, it was time to install the rib attach clips. These have to be match drilled to the prepunched holes in the web components, so we had to take things apart and use one layer of the web as a template for each pair of clips. You clamp one side in place and drill it from the backside—then take it off, clamp it to its mate, and drill the mate. Once you have done this for all of the clips, you can re-assemble the spar web, Cleco the clips in place, then up-drill the holes to final size. Con- ceptually that is easy—it is just always disheartening to take things apart once they have been put together. Well… that’s tough—it’s all going to come apart again for deburring anyway! Keep it Square The large wing attach blocks were next. The holes are finished to ¼ inch at this stage, and they’ll be upsized later

46 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes when the spars are matched together. the drilling chips out of the slots! Make We found it easy to line up the ¼-inch sure you clean those out, or you might holes with a temporary bolt, then hold not get the height that you want. We the block straight using a combination used quite an assortment of clamps to square, and match drill the attachment hold things in position for drilling, but bolt holes. You quickly become adept that’s the result of building such long at figuring out these little processes and spars. Lining things up and measuring making sure that things remain square. is something you’ll want to do several Don’t rush—it is just so easy to get the times. The spar caps are the most criti- hole to the wrong size, and once you cal part of the structure, and in the case have drilled it too big, you will have of the Xenos, they are not predrilled. So ruined a lot of parts. once you start drilling, you are setting Once you have matched drilled all of the final geometry and edge distance. the thick layers and attached the vari- As with the rest of spar assembly, ous clips and parts to the web, it is time we decided to start with a #40 drill to think about the spar caps. But first, bit and silver Clecoes to hold things think about how to line them up. The together. We initially drilled approxi- height of the spar is given as 739/64 inches mately every foot or two to hold things from root to tip, and getting that right in alignment. The spar caps do flex, and is important if you don’t want to create wider spacing will allow them to wave a The “T” spar caps slide in nicely once the problems down the road of wing assem- little bit if you’re not careful. Long drill slots are adequately cleared of aluminum bly. Unfortunately, there is room for bits are required in order for the drill shavings and other debris. The drill jigs slop in the slots in the web, so you need motor to clear the edges of the caps, so ensure they are properly placed before drilling commences. to position the caps precisely before having a bunch of six-inch bits on hand drilling. Sonex helps you out here with is good prep for the drilling. Remem- the problems with this approach is, of a few drill jigs that get Clecoed into rib ber that silver spring-type Clecoes will course, the Clecoes that you put in on attachment holes in the outboard two- not fit all the way through the stack, so the top. The assembly will want to sit thirds of the spar. But they don’t give you might have to go right up to a #21 on the Clecoes once you flip it over, you many, and we found that taking the to get a bolt in to hold things together. so you either need to put in enough of time to make a bunch more really sped You can use short #40 drill bits as these “legs” to keep everything stable, things up later. We used some 1/8-inch alignment pins while drilling the large or you’ll want some 4x4 blocks about 6 scrap aluminum and drilled them as a holes until you get enough bolts in to inches long to stand the assembly up off stack to give us a matched set. keep everything rigid. the bench in a stable fashion. The other tool we made to give us a It took a lot of care to drill precisely Black (-5) Clecoes are your friends precise spar height was a modified com- perpendicular to the spar web and when you get to the last dozen feet or bination square. We started with two avoid nicking the caps with the edge of so of the outboard ends. The web is identical squares and took the slide off the bit. Take your time, and don’t feel thin enough out there that the spring one square, turned it around, and put it like it all has to be done in one session. Clecoes will hold, so beg, borrow, or on the second square. With two slides Once you have placed bolts or Clecoes steal about 250 of them, and you’ll be in on one square, we had, in effect, a large, every foot or so, both top and bottom, good shape. This, in combination with deep and square caliper. We set this for the assembly should pretty much be the 4-mm bolts, (about 300 of them), the spar height and slid it on the assem- dimensionally fixed. should give you enough temporary fas- bly every time we were going to do some When you get outboard a ways, the teners to hold a Xenos spar together. If drilling to make sure we kept the dimen- layers of web material tend to alter- you’re building a shorter spar, you can sion perfect. Making tools and jigs can nate on the front and back of the spar get by with less. really help when you are working on a cap flanges. This means that to see the Next time, we’ll take a look at how large repeating structure. In the end, the prepunched holes in the webs, you’ll you rivet this thing all together. We’ll time spent on tools will be paid back in have to flip the spar over to drill many start with disassembly, deburring, dim- simpler and more precise building. of the holes. Make sure that you have pling, and countersinking (the inboard drilled as many of the holes as you can edges overlap in the fuselage and sit Adding the Spar Caps before you flip to hold things in align- flush with each other, so many of the If the layups for the web have been ment—and then check the alignment rivets and bolts have to be flush as well), assembled properly, the upper and lower and clamps once again after the big flip. then reassembly and riveting. How do spar caps should slip right into their If you plan this right, you’ll only have you set -5 rivets? Join us next time and slots. They did for us, once we blew all of to do this once! We found that one of we’ll show you how it’s done. J

KITPLANES March 2018 47 Sandwich Panels, Part 5: A Simple, Accurate Method for Molding Flanged Parts By Eric Stewart

This month’s column is the second of a two-part discussion on how to make flanged sandwich parts. We continue the process here with prepping the male mold for layup. Once you have the mold mounted to the base, mix up some Bondo and make a radiused fillet at the base of the mold. Smooth foil tape down with a credit card. Leave enough overhang to cover the top mold radius. Trim any tape that overhangs at the bottom. This helps the carbon sit flush against the side of the mold when you do the If there are any large dings, holes, etc. alcohol, a water soluble release agent). layup. When the Bondo has cured to a in the mold that you don’t like or think Harbor Freight’s 6.75-ounce touch-up rubbery state (usually a few minutes), might trap the part in place, you can fill air spray gun works fine and cleans up use a chisel to scrape off the excess. It them with modeling clay. Next, wax the easily. (Since PVA is a release agent, it’s comes off pretty clean if you time it mold and fillet with a release wax like best to use this gun for PVA only, to right. You can also run a rag with ace- Meguiar’s #8. I find a single application avoid cross contamination.) tone over the foil to remove any remain- of wax to be sufficient. Finally, shoot Because the PVA can puddle over ing flecks of Bondo. the mold with a coat of PVA (polyvinyl waxed surfaces, I shoot the first two

48 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes (Left) Use a chisel (wood or soft plastic is a bit more forgiving than metal, which easily gouges the foil tape if you aren’t careful) to clean up the radius at the base of the mold. Radius with a tongue depressor/mix stick, and hold the stick so that it completely scrapes off the Bondo at the edges tangent to the base and vertical mold edge. This makes peeling off the excess Bondo simple. No sanding required. (Right) When coupled with PVA, cheap car wax seems to work just as well as mold release wax.

(Left) Shooting the mold with PVA release agent. (Right) Bagging tape is offset about one inch from the mold base and Stretchlon is offset about two inches from the tape. coats as a very light mist. This avoids puddling and provides a base for subsequent coats to adhere to. I then shoot three heavy coats, letting each coat dry (about 10-15 minutes at room temperature). Because PVA is a release agent, be sure to only spray in a contained paint booth or other area where you don’t have to worry about overspray contaminating your work tables, carbon cloth, etc. Applying Tape and Stretchlon Once the final coat of PVA has dried, tape the mold base to the tempered glass (to keep it from moving about while you do the layup), and run a strip of tacky tape around the perimeter of the base. Leave the wax paper in place on the sides and bottom, but remove it across the Bag prep. Clockwise from upper left: 1) Press seal upper left corner, working from left to right. 2) Press seal upper right corner, working from right to left. Leave 3–4 inches top. Cut an oversize sheet of Stretchlon unsealed in the middle, so you can insert pleat tape. 3) Insert pleat to take up extra (I usually aim to have the Stretchlon material. Cut pleat tape longer than the pleat and fold over on itself when sealing the extend about 2 inches beyond the edge pleat. 4) Roll bag to top of table until layup is finished.

Photos: Eric Stewart KITPLANES March 2018 49 Carbon that has been pre-wet out on transfer plastic is placed on the mold. Trim as Part under vacuum. Picture was taken necessary before removing plastic. The scissors here are Kai 7300 12-inch bent handle just after bagging, so there is no bleed scissors—expensive, but definitely worth it if you spend much time with composites. through into the breather yet. of the tape), and stick it in place on the a core, and two layers of unidirectional bleeder/breather. Don’t forget to set upper left corner with the Stretchlon tape. First wet out the BID and uni on your quick disconnect in place before extending about ½ inch beyond the tape. a piece of transfer plastic (again, I like closing the bag. Now you are ready to Now press seal the Stretchlon about the 3.5-mil transparent plastic from close the bag. Seal the remaining three halfway across the top. Move to the Lowe’s). Transfer the first ply of BID, edges like the first, starting at one corner, opposite corner, attach the Stretchlon remove the plastic, and brush the BID working about halfway along the edge, there, and press seal the Stretchlon, down smooth against the mold with an then moving to the other end and meet- again moving toward the middle. When acid brush. Most mold shapes will need ing in the middle with a pleat. Apply there is about a 3-inch gap between the to have a bit of fabric snipped out at the vacuum, ensuring that your breather left and right sides, add a 3-inch long corners or elsewhere to lay down nicely. doesn’t shift as it’s pulled down. Because piece of tacky tape as a pleat (you should It’s much easier to do this while the BID the Stretchlon is so stretchy, it will usu- have enough Stretchlon to form a pleat is still on the transfer plastic. ally try to bridge the corner between the since you cut it oversize). Now roll your Next, wrap the uni around the mold, side of the mold and the base. Be sure to bagging film up out of the way for the keeping it taught as you go. Continue press the bag tightly into this corner to time being. Although I often use Lowe’s with the remaining layers of BID. Don’t ensure that the fabric is molded tightly 3.5-mil aviation plastic for relatively flat forget to place the foam core after the to the side of the mold. If the parts you bagging jobs like wing skins, I prefer second layer. I prefer to wrap the uni are making are small, I recommend cal- Stretchlon for bagging these types of after the first layer of BID. That way, if culating the fiber/resin ratio to make parts, since you get much better confor- you need to sand the flange at all, you’ll sure it is within spec, as it’s easy to over- mity around the male mold. have to go through several layers of BID bleed small parts, especially if there are before you risk damaging the uni. There’s few plies, the shop temperature is high Layup a link at the end of this article where you (i.e., epoxy is less viscous), or you have a You can now proceed with your layup. can watch a time-lapse video of a layup. strong vacuum pump. For example, suppose you want to make Finally, add the usual materials for a 2-core-2 rib with four layers of BID, a bagging operation—peel, perf, and Trimming to Size Once the part has cured, unscrew the mold from the base. Use a Dremel (the diamond cutoff wheels work great for trimming carbon) to trim along the base of the part, just above the radius. Remove this area as well as the Bondo radius (it should flake off pretty easily). Begin the demolding process by blowing compressed air into your alignment holes. This usually gets the top face loose, and if you’re lucky, that’s all it takes to pop the part off the mold. If not, try to free up the flanges by gently prying them up (Left) The first step in demolding is to trim the bottom of the flange. (Right) Blow with a chisel. If the flange isn’t too thick, compressed air into alignment or screw holes to help pop the part free. you should be able to jam a credit card

50 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes (Left) Flanges can be freed up with a credit card. (Right) Tap the part free while gripping it in a vise. between the flange and mold and run it worst you can drop the part in a bath of screw that holds the diamond blade in around the perimeter of the mold. Try to water. The PVA will dissolve, and the place run along the surface of the mold free it with compressed air again. MDF should get soft enough to carve out. as a standoff. Then follow up with a If the part hasn’t popped off the mold at Once the part is free, you can unscrew sanding block and sand the flange level this point, you can grip the exposed MDF the bottom of the mold (if you have two with the mold. Voila! You now have base with a vise. Gently tap the flange edge pieces of MDF stacked together), rein- a perfectly straight mold edge that is with a hammer and piece of flat alumi- sert the top mold face, and use this as a exactly ¾ inch deep. You can make it num stock to push the part off the mold. trim and drill guide (if you incorporated deeper by putting spacers underneath The above methods have never failed to alignment holes into the template). Use the mold, or shallower by routering a free a part for me, but if worse comes to the Dremel for the initial cut, letting the shallower face mold to begin with.

Left) Initial rough cut with a Dremel. (Right) The screw head is about 1/16 inch high, enough to avoid undercutting the flange as long as you hold the Dremel perpendicular to the mold.

(Left) After removing the part, reinsert the top mold (and any necessary spacers to achieve the desired flange depth) and trim/sand flush. (Right) This rib needed a 1-inch-deep flange, so I inserted a ¼-inch plywood spacer under the ¾-inch MDF mold to achieve a total depth of 1 inch.

KITPLANES March 2018 51 Rib fit is excellent and dimensionally accurate. Molded ribs in the SR-1 wing. You can now use a micrometer to check the thickness of the flange. Minimum Bend Radius Hopefully you are close to spec. This When originally developing this method, I was curious how sharp the corner between is why it helps to make a practice part the flange and rib could be. A smaller radius has two benefits: under tensile or side loads or two, to confirm the material thick- (imagine trying to rip the rib or bulkhead away from the skin to which it is bonded), the ness used in your offset calculations. flange corner is the weak point in terms of delamination, since this is where the bond In my experience, thick layups tend to will typically begin to fail in peel. The designer can mitigate this by ensuring this corner come out over spec if not bagged prop- has a nice fillet of adhesive and possibly a taped reinforcement. With a smaller radius, erly, so you may need to take this into the peel forces are lower (= stronger joint) and the size of the reinforcing fillet is smaller account. If you are over spec you can (= lighter joint). sand the flange down, if that is accept- Like metal, fibers also have a minimum bend radius. When a material is bent, the mate- able. If you are under spec, you can rial on the outside stretches, while material on the inside compresses. At a point in the increase your bond line thickness to middle (called the “neutral line”), the material neither bends not compresses. The failure take up the margin. in these bends usually occurs on the outer fibers. Calculating the radius of curvature that I hope you’ve enjoyed this two- will cause the outer material to break then gives the minimum bend radius, which is then part article on molding flanged parts. increased to account for a safety factor or knockdown factors. There’s no reason why this method can’t I found two papers discussing minimum bend radius calculations in carbon fiber, both be applied to a variety of aircraft parts of which gave a minimum bend radius of about 0.2 millimeter (.007 inch) for carbon fiber besides ribs and bulkheads, such as an fabric1. A 1/16-inch (1.5-millimeter) radius round-over bit thus gives an adequate margin of instrument panel, baggage compart- safety. Note: (a) The bend radius increases with each subsequent layer of BID, and (b) BID ment, etc. So give it a try and send us wrapped around a 90-degree corner actually forms an ellipse, but the minimum radius is pics of what you build! You can see the still equal to that of the corner itself. time-lapse video of a rib layup at www. —E.S. facebook.com/TheSR1Project.J 1Both papers derive minimum bend radius using the bending moment equation: ED St Eric ρmin = Eric Stewart is designing (2σfu ) Where and building the SR-1, ρmin = minimum bend radius a speed plane for setting E = fiber’s Young’s modulus (i.e.; modulus of elasticity) records in the FAI c-1a/0 D = fiber’s diameter category (takeoff weight less σ = fiber’s ultimate tensile strength fu than 661 pounds, including and for Hexcel style 282 carbon fiber (AS2C fiber) e pilot and fuel). You can see

E = 221 GPa wart D= 6.9 microns more at www.facebook.com/ σfu = 4.44 GPa TheSR1Project, including giving additional photos and videos ρmin = .17mm of the subjects in this series The mathematically equivalent approach using elongation of fibers can also be used of articles. (ρmin = D/2 x [100/% elongation]-1)

52 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes The Creative Homebuilder Make Your Own Air-Flow Speed Control By KITPLANES® Staff

Most of us experience the frustra- down and smooths out the pulling pro- tion of a pneumatic, pull-type rivet gun cess with pneumatic rivet guns. going from no movement to extreme When the Creative Homebuilder speed that generates a startling “shock” uses his larger MYO yokes [“Make Your action. The same jolt can happen on Own Yokes,” January 2018], he adds pneumatic squeezers, sometimes with a speed control. When converting the undesirable results. The Creative pneumatic head for foot use, the feath- Homebuilder uses his make-your-own ering hand trigger assembly is removed (MYO) fixed air restrictor to allow a and replaced with an adapter that lets more controlled action on the air tool air pass either way without the trigger- he is using. ing (or feathering) action of the original. He starts by drilling/tapping the bore To recover the feathering sensitivity, he of a coupling adapter to accept a brass installs the orifice at the inlet to the Allen hex screw. He then drills an orifice foot valve, which slows down the rate at hole to allow airflow restriction in the which the air enters the cylinder of the screw—usually in the 0.025- to 0.040- squeezer. This, in turn, slows down the Close-up view of speed control with modified Allen hex screw inserted into inch range. Once the screw is installed operation rate. Work potential remains the coupling adapter. The orifice hole is in the adapter, the fixed air restriction is the same, but work takes place at a barely visible in the center of the installed accomplished. This speed control slows slower rate. J Allen hex screw.

The original materials: a brass coupling adapter (left) and brass Allen hex screw (right). All bagged up and ready to go!

KITPLANES March 2018 53 PLANE and SIMPLE

Drilling in Tight Places By Jon Croke

Drilling hundreds of holes is typi- “impossible” drilling scenarios, but each Top to bottom: the inexpensive Tight Fit cally a mundane task while building needs to be addressed properly. We must drill, a typical right-angle drill attachment, short drill bits used with right-angle drills, our aircraft. Whether using an electric use the tools that are made for drilling and foot-long drill bits. or air-driven drill, the drilling process in tight places. Fortunately, there are a is usually stress free. But every once in a couple of affordable tool options avail- use for making rivet holes. The flexibil- while, we are confronted with a scenario able for this purpose. The least obvious, ity of their long length allows you to flex that restricts our drill bit from getting least expensive, and most surprising the shaft with your fingers around barri- a straight shot to the desired hole loca- solution is the foot-long drill bit. ers as needed. tion. A sense of panic or frustration sets The foot-long drill bit excels by simply The right-angle drill is the ultimate in as we cannot get our drill properly keeping the drill motor far away from tool for tight drilling locations. It is avail- positioned. If we try to cheat and drill the target hole. This is often all that is able either as an attachment to your con- at an angle, this often results in a ruined needed to prevent interference that ventional drill motor (best value) or as a part or, at best, an oblong hole. would otherwise prevent a straight shot self-contained unit in either electric or air- Maybe only a handful of situations to the desired hole location. These long powered format. Combined with special during the aircraft build pose these bits are available in the popular sizes we drill bits, they provide a reliable solution

54 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Jon CRJon As the founder of Homebuilt PLANE and SIMPLE HELP.com, Jon Croke has produced instructional videos for Experimental aircraft builders for over 10 years. He has built (and helped others build) over a dozen kit aircraft of all makes and

O models. Jon is a private pilot and

KE currently owns and flies a Zenith Cruzer.

(Left) A difficult location for hole making with a conventional drill. (Right) Either a foot-long Drilling with a right-angle drill bit or a right-angle drill attachment makes accurate drilling possible in restricted locations. attachment takes a little practice—it to the most challenging drilling loca- (approximately $100–$250). A com- is easy for the bit to catch in the hole tions. Most right-angle drills of the style pany called Tight Fit makes a nice econ- as it breaks through the material. This shown here share a common style of drill omy model for about $40. The internal is often due to not keeping the bit per- bit: one end has a ¼-inch 28 threaded parts wore out in my Tight Fit after my pendicular to the material, as it is hard shank, and the cutting end is available in second aircraft build, but it was well to judge with the bit length being very many popular diameter sizes and lengths. worth the value in getting all of my next- short. Letting up on the pressure as the Since the right-angle drill attach- to-impossible holes drilled properly. The bit breaks through will definitely help. ment is only occasionally used in a proj- more expensive, durable models will last These tools and their drill bits are avail- ect, builders may not want to invest in a lifetime, and many come as a kit with able from your favorite aircraft tool sup- the somewhat high price of these tools popular drill bit sizes included. plier and the likes of Amazon.com. J Magnet Clamps By David Paule SHOP TIPS

Occasionally it’s impossible to arrange for clamps in some areas. Since I’m building an aluminum airplane, I can use magnets to hold the parts together. These magnets are neo- dymium rare earth magnets, and they are quite strong. Mine are 1/16 inch thick by 1/2 inch in diameter. It would be better if they were 1/8 inch thick because once in a while these break. Be careful handling them because they can cause injury, especially if a stack of them gets close to something. If you’re separating some parts that have been clamped with these, as they separate they’ll lose their clamping force and are free to move around. If there’s anything steel around they’ll jump to it as they fall. This can cause injury if you’re not prepared for it. Additionally, the magnets can lodge and stick in unexpected places. Please use caution when working with them. I buy mine from K&J Magnetics, Inc. (www.kjmagnetics.com), and the ones I buy are the N42 type. They are axially magnetized and have a force of about three pounds, becoming less as the gap between them becomes larger. I’ve found that they work just fine across a stainless steel firewall, and parts slightly greater than1 /8 inch thick are not a problem. They can also be stacked for more force if necessary. J

KITPLANES March 2018 55 MAINTENANCE MATTERS Three Battery Problems Lead to Accidents Three battery-related accidents, one retract the gear? That is a question the initial climbout. Also, don’t forget that a now 10 years old, the others more recent, lawyers debated in court, but their argu- depleted battery is going to draw more point to the need to understand and ments are not of much use to a pilot who than the normal amount of charging properly maintain your airplane’s electri- suddenly finds himself flying a glider. current. A low-voltage situation could cal system, especially the battery. Batter- Alternators are sized to handle continu- happen to you. ies are simple and reliable in most cases, ous loads and recharge batteries, but but in an age of ever-increasing depen- transitory loads such as a flap retraction Subaru-Powered GlaStar dence on electrical power, it is vital that are not included in the alternator capac- A GlaStar with a Subaru auto conver- their maintenance and use is well under- ity calculation, nor is excessive battery sion engine crashed after one bat- stood. Here are three accidents that illus- charging caused by starting out with a tery in a two-battery electrical system trate that point. dead or near-dead battery. Airplanes are failed. It’s another case where the pilot not like cars that come equipped with assumed that an electrically dependent Diamond Twin Star 100+ amp alternators and huge batteries plane that would not start on its own A Diamond Twin Star with dual Centu- with plenty of capacity for abuse. could be safely flown after a jump-start. rion diesel engines crashed after takeoff The lesson here is, do not take off in Unfortunately, it ended in tragedy, with when the fuel management systems of an electrically dependent airplane if the a severely injured pilot and a totally both engines reset after a low-voltage battery is too weak to start the engine. destroyed airplane. It just cannot be condition, causing a dual engine failure. Take the time to charge the battery or said often enough—if your electrically The airplane in question had a dead bat- batteries first. A second lesson is, be sure dependent airplane will not start on its tery when the pilot attempted to start to know the minimum voltage required own, it is vitally impor- the airplane. A ground power source was to run your engine’s electrical systems. tant that you correct used to jump-start the engines. During See how that compares to the actual the problem before takeoff, a short time later, the battery system voltage you have when cranking attempting flight. was still insufficiently charged to sustain your starter. It might surprise you. the sudden extra power demand of the Since most Experimentals do not gear retraction motors. When the volt- have retractable gear, it might be fair to age dropped below the critical level, the ask if this incident is really applicable. electrically dependent fuel manage- That’s a fair question, but don’t forget ment systems of both engines reset and that many planes have electric flaps and stopped the engines in flight. Diamond pitot heat—two big users of electrical had specifically warned against starting power that could be engaged during both engines with ground power, but the The EarthX battery has become a popular warning was not heeded. The plane was choice for builders who wish to take advan- destroyed and lawsuits ensued. The point tage of the considerable weight savings is that electrically dependent airplanes it affords. Be sure to connect the battery need fully charged batteries to fly safely. warning light and external overvoltage protection if you decide to use one of these You might ask, if there was enough batteries. They are much more subject to cata- power to excite the fields of the alterna- strophic failure than conventional batteries if they are tors, why wasn’t there enough power to not properly charged and protected. (Photo: Courtesy of EarthX, Inc.)

Dave Prizio has been plying the skies of the L.A. basin and beyond since 1973. Born into a family of builders, it was only natural that he would make his living as a contractor and spend his lei- sure time building airplanes. He has so far completed three—a GlaStar, a Glasair Sportsman, and a Texas Sport Cub—and is helping a friend build an RV-8. When he isn’t building something, he Dave Prizio shares his love of aviation with others by flying Young Eagles or volunteering as an EAA Techni- cal Counselor. He is also an A&P mechanic, Designated Airworthiness Representative (DAR), and a member of the EAA Homebuilt Aircraft Council.

56 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes When you first get in your plane before Harbor Freight sells a very affordable battery condition tester for about $50. If you get attempting to start it, turn on the master one be sure to open it up and tighten all the connections before using it. After that, it switch and check the voltage of the works well for light-duty use. Here it is hooked up to a Concorde RG-25XC battery. battery. This battery, at 12.2 volts, may barely start the plane, but it can’t be they only work if you know the condition occur in flight. The fact that the plane relied upon for good performance on of each battery and isolate any deficient was hard to start seems to point to a the upcoming flight. Time to charge it up component in the electrical system. battery problem that developed before and check it with the condition tester, or Unfortunately, hooking both batteries takeoff. If such a problem did develop maybe replace it. up to the main bus where a single alter- in flight, an otherwise unexplained Electrically dependent really does mean nator can charge them masks a problem increase in charging current would likely that the airplane engine will not run with either battery. This is what bedev- be the only early indication. without electrical power. iled this GlaStar pilot. The lesson here is that, once again, The builder of this plane, no doubt The way to find this problem is to if a plane won’t start on its own power, with safety in mind, installed two batter- check the voltage of each battery before find out why before flight. Another les- ies in his Subaru-powered GlaStar. The starting the engine. With a switch sys- son is that two batteries do not actu- electronic engine management system tem that connects each battery sepa- ally equal a fully redundant system. It of that engine requires nothing less. The rately, it is easy to turn off each battery is nearly the same as having a single plane was equipped with a switch that before flight and check the voltage of larger battery if it is not managed prop- would permit running on either or both the other one. If either battery is not erly. This is why some electrical design- batteries. The NTSB report, however, reading at least 12.5 volts, it is probably ers have embraced the dual alternator, says that the batteries were connected not a good idea to fly with it. Such a single battery concept, especially if in series. It also says that there was no check would have easily prevented this one of the alternators is a permanent- field investigation by the NTSB, so we are accident, assuming the short did not magnet type. left to speculate about what the electrical system really looked like. Obviously, connecting two 12-volt batteries in series would produce 24 volts, which was not the intended design for the 12-volt system. In any case, the plane would not start without ground power. After starting, the pilot reported a 14.2-volt reading consistent with the charging voltage of a 12-volt alternator. There was no report of charging current. As it turned out, one of the batteries had a shorted cell that caused it to produce much less than 12 volts. This eventually drained the other battery to the point that it would not produce enough voltage to power the electrical system. Once system voltage dropped too low, the engine shut down, leading to the crash. Dual batteries for an electrically Turn the battery tester load to one-half the maximum cold-cranking amp rating to test dependent airplane are a good idea, but its condition. Sadly, this one needs to be replaced.

Photos: Dave Prizio KITPLANES March 2018 57 Overvoltage Leads to Battery Failure The recent forced landing of an RV-8, in which the owner (not the builder) had replaced the Odyssey battery with a new lithium battery, illustrates a point I have been trying to make for some time: Airplane electrical systems need overvoltage protection. Everyone wants to cut a few pounds out of their airplane’s empty weight, and what easier way is there to do that than replacing your PC680 Odyssey battery with a new lithium battery. In a few minutes, you have shaved off 10 pounds. But lithium batteries have special challenges This B&C voltage regulator matches up well with their alternators or any other alternator that go with their impressive weight sav- that does not have built-in voltage regulation. It includes overvoltage protection in its circuitry. For best results mount this inside the cabin, rather than in the engine compart- ings. They are sensitive to mischarging, ment. (Photo: Courtesy of B&C Specialty Products, Inc.) overcharging, and excessive voltage. Tra- ditional batteries do not like such abuse producing excess voltage, possibly as An unprotected overvoltage condition either, but when subject to it, they do much as 70 volts or more at some point. when using a lithium battery could be not usually catch on fire. The best new This is what is called a runaway alterna- even worse, potentially putting the very lithium batteries have built-in circuitry tor. It is not common, but it does happen. survival of the aircraft in peril. In this case meant to protect the battery from these New alternators and voltage regulators that is exactly what happened. The run- perils, but we are still learning about how tend to have built-in overvoltage protec- away alternator caused the lithium bat- robust these protections may be and tion to prevent this condition, but older tery to begin melting. Whether or not it their possible failure modes. models generally do not have this safe- would have actually caught fire at some In the incident in question, two very guard. In this day of electric panels that point is unknown in these particular cir- experienced pilots were out flying include not only radios but electronic cumstances, but even such a possibility is when the airplane’s alternator, a Bosch engine and flight instruments, an over- chilling, and only quick and skillful action automotive unit with a built-in voltage voltage condition that could disable by the pilot prevented a loss of life. No regulator, malfunctioned and started electronic items could be devastating. doubt this is what the pilot had in mind as he executed a very abrupt emergency Alt descent maneuver. 1 Batt 1 relay The pilot said he thought such a failure – + could not occur because of the built-in protections that were included in the battery. It appears, though, that the bat- Battery 1 tery’s protective measures were simply overwhelmed. Further investigation may or may not reveal why the battery failed AV Buss AV

Main Buss to protect itself. It is not in very good condition at this point. There was no overvoltage protection included in the AV relay aircraft electrical system. Batt 2 relay – + Alt Overvoltage Protection 2 A question arises, how do I know if I have Battery 2 overvoltage protection in my electri- Acft Buss cal system? This is especially important Schottky Diode P/N 122NQ030R For Ref. Only if you did not build the plane. For the last several years, Plane-Power has been Connecting two alternators and two batteries does not have to be complicated as this schematic shows. Of course, each alternator will have its own voltage regulator and over- including overvoltage protection in voltage protection (unless already built in), plus its own field power switch to energize it most of their alternators. B&C has always or take it offline if necessary. (Schematic: Courtesy of Aerotronics, Inc.) included it in their voltage regulators.

58 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes you should probably be thinking about a new battery. To really be sure of your battery condition though, you need a load tester. Such a tester is available from Harbor Freight for about $50. If you have an electrically dependent airplane, you should have one of these testers, or one like it, and use it at least annually. One of your preflight steps should be to check the voltage of your battery before you crank the starter. If you have two batteries, be sure to isolate and check each one. If they are not up to the task, they need to be charged or replaced. Expect to see a slightly lower voltage at the main bus than you see when testing the battery directly. This drop should not be more than about 0.2 volts. If it is, then suspect problems with wiring or connec- This Plane-Power alternator is in the process of being installed in an RV-8. It features tions in your electrical system, or possibly built-in voltage regulation and overvoltage protection. The downside is that these a master relay that is getting old. features are in the harsh environment of the engine compartment. The age of aviation electronics is here, However, if your plane is older, it may care to be sure your battery or batteries and it is mostly wonderful, but there are well not have this protection. If you are are in top shape. Your fully charged bat- a few things you need to understand if unsure you can contact Plane-Power to tery should put out 12.7 to 12.8 volts if it you are going to fly safely in this new see if your alternator has this feature. If is in top condition. If it won’t put out at environment. Be sure you learn what you find that you do not have this vital least 12.5 volts when it is fully charged, they are. J protection, you may be able to add it. For the do-it-yourselfers, check out Bob Nuckolls’ schematic in his AeroElectric Connection, which is available online for no cost. Or you can go straight to the information here: www.aeroelectric.com/ Print and Digital Book/AEC_R12A.pdf. His design is only for alternators that do not have internal voltage regulation. Be sure you understand the features of your alternator before you attempt to use his circuitry. The admonition to include overvoltage protection in your aircraft electrical system is not just for people with lithium batteries. Remember, overvoltage can permanently damage avionics and EFIS systems. This can cost you thousands of dollars, not to mention putting you in a perilous situation in flight. Imagine flying in IFR conditions and having a total panel failure because of an overvoltage condition. Spend a few dollars now and avoid these problems forever.

Battery Condition If you have an airplane that must have Either Format – Great Savings! electrical power to run or to power its Subscribe Now at www.kitplanes.com/subscribe instruments, you need to take special

KITPLANES March 2018 59 HOME SHOP MACHINIST Spline-al Tap Spline shaft couplings are ubiquitous in machine and mechanism design. They exist in one form or another on virtually every vehicle on the road or in the air. While the engineering requirements for ANSI-standard involute splines can be a little complex and the tooling requirements specialized, straight-side and V-side splines (also called serrated splines) on shafts up to ½-inch diameter are easy projects for the home shop. All Examples of a straight-sided spline shaft (left) and a V-spline (or serrated-spline) shaft (right). you need is a lathe, a vertical milling machine, and a 5C spin indexer. The 5C spin indexer is the go-to tool for making splines. Every shop should have one. In previous columns I have used the spin indexer for a variety of cool jobs, such as knobs [“Home Shop Machin- ist,” September 2013] and flats [“Home Shop Machinist,” September 2016]. The indexer combines simple collet clamping with 360° whole number indexing. You Examples of the broached sockets that mate with spline shafts. could do the same job on a rotary table or dividing head, but the spin indexer is easier to set up and less complicated in operation. As long as you keep to a number that divides into 360 (e.g., 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, etc.) you can use a spin indexer. The straight-side spline example for this column was 3/8-inch diameter with nine splines. The grooves between each spline were cut 0.040 inch wide (the width of my 2-inch, 110-tooth slitting saw) and 0.020 inch deep. The V-sided spline example was 5/16-inch diameter with 18 splines. The V-grooves were machined with a standard four-flute,3 /8-inch diameter square-end end mill. How many splines and what type The 5C spin indexer is conveniently clamped into position using the mill vise. For the (straight or V) depends mostly on what straight-side spline, a slitting saw was used (shown); for the V-side spline, a standard end looks right for your project. For the mill was used.

Bob Hadley is the R&D manager for a California-based consumer products company. He holds a Sport Pilot certificate and a Light-Sport Repairman certificate with inspection authorization for Bob Hadley his Jabiru J250-SP.

60 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes The width of the grooves for the straight-side For a 5/16-inch shaft (left) that will have 18 splines, the Y and Z tool edge position dimension spline was based on the 0.040-inch-wide “D” = 0.067 inch. This orients the first groove to be cut on the 45° position, and after slitting saw. After sketching various options, indexing (clockwise in this view) all subsequent cuts are on that same 45° position (center). I decided that nine splines machined to a Note the root diameter (right), which determines the pilot hole necessary to make the depth (D) of 0.020 looked the best. broach and, subsequently, the female socket.

Touching off the tool from the 12-o’clock Turn a length of W1 tool steel to resemble and 9-o’clock positions simplifies the the above form. Note the step in diameter set-up. A nine-spline example is shown and 5° relief angle behind the leading for clarity, but the idea is the same for edges of the first two steps. The pilot hole any practical number of splines. diameter is dictated by the ID of the root of the spline grooves. Leave at least two projects shown, I used the 2D drafting inches of extra length (100% of OD) for module in Solid Edge (available from holding in the collet and to allow tool clerance from the indexer when milling. Siemens for free at http://tinyurl.com/ After grooving, lathe-turn a relief to the y8ftse36) to make a number of sketches pilot hole diameter and part off. before deciding the spline count. Any basic drawing program or CAD software $5.20. The three-foot length of 0.375 can be used. You can also use a pencil (3/8) was $8 (prices from McMaster-Carr). and a protractor, but CAD is preferred Depending on your project, you might because it will give you the most precise consider using W1 (in the unhardened dimensions to reference your tool posi- state) for the spline shaft as well. tion and machine setup. W1 tool steel is ideal for making home- A spline shaft is not much use unless shop broaches because it is very forgiv- you have a handle, knob, or coupling, ing to machine, heat treats easily with a for it to mate with. To assure compatibil- propane torch, quenches in water, and ity with your custom spline, prepare the can be tempered in a toaster oven. The shaft stock and the broaching stock at resulting tool will have good hardness the same time. (50+ Rockwell C) and can be used to The broaching tool starts out as a broach more than a handful of sockets length of W1 (W for “water hardening”) before any appreciable wear. tool steel the same diameter as your Other than the tool position (for spline shaft. straight-side splines the tool is on the W1 rounds are also called “water hard- shaft centerline at 90° and for V-sided ening drill rod.” W1 is precision ground splines it’s at 45°), the procedure for mill- and available in common drill sizes from ing the grooves is the same. 0.062 to 2-inches diameter. The cost for Put the shaft in the indexer with one The V-spline broach. The dark color is the a three-foot length of 0.3125 (5/16) was to two inches of length protruding. Since result of heat treating.

Photos: Bob Hadley KITPLANES March 2018 61 you can’t mill grooves right up to the collet (the tool will hit [crash into] the collet), you need to account for the tool diameter and figure out how much stock needs to protrude to get the desired groove length. Keep in mind you want the stock to protrude as little as possible and still be able to mill the grooves to the desired length. Once you’re satis- fied, set and secure the X-axis table stop (see “Home Shop Machinist,” July 2017). (Left) Making the first groove for the straight-side, nine-spline shaft. (Right) The broaching This will assure the grooves are all the blank after all the grooves have been milled. Note how the mill’s travel limiter assured all the grooves are identical length. same length. Tighten the collet and set the inch. With the paper between the cut- the V-grooves I ran the 3/8-inch end mill indexer to “0.” You are now ready to ter and the stock (and the mill off), at 900 rpm and for the slitting saw, 450 touch off the tool and dial in the cutter slowly bring the table up until you just rpm. Keep the feed rate slow and easy position (shown in the sketches as “D”). begin to feel the cutter starting to drag to the stop limiter, and then back com- Use an edge finder to locate the side of on the paper. Stop there. Set the Z axis pletely out of the cut at the same slow the shaft and set zero. To zero the top dial to zero + 0.004 (four thousandths). and easy rate. Once clear, pull the indexer edge, with the mill off, center the cut- This method prevents the tool edge lock pin and rotate the part according to ter over the shaft and bring the quill from chipping or gouging the part and, the number of splines you want (e.g., 20° down (or crank the table up) until the with practice, can be as accurate and for 18 splines and 40° for nine splines). cutter is almost, but not quite, touch- reliable as any other. Repeat until all splines have been milled. ing the stock. Take a piece of regular Position the cutter clear of the free end That’s all there is too it! We’ll pick up inkjet/laser printer paper and measure of the part and dial the table in to line up next month with heat treating the broach the thickness. It should be about 0.004 the cutter to make the first groove. For and making the sockets for the handle. J Kitplanes subscriber alert! several of our Kitplanes subscribers have received what appear to be “renewal notices” or “automatic renewal notices” from a company known as preMier subscriptiOn serVice, 5star subscriptiOns, rapiD MaGaZine cOllectiOn, MaGaZine billinG serVices, publisHer’s billinG serVices, circulatiOn billinG center or other similar names. Addresses for these firms include Dallas, tX; lincoln, ne; Omaha, ne; san luis Obispo, ca; salt lake city, ut; White city, Or and prescott, Fl. These firms have nOt been authorized by us to sell subscriptions or renewals for Kitplanes and we cannOt Guarantee that any order or payment sent to them will be forwarded to us. Kitplanes does nOt offer a subscription term of more than 2 years, nor do we retain your bank account information. if you see an offer for 3 or more years or if you receive a notice that references your subscription anD your banking information, it is nOt an authorized offer. We urge you to report these notices to us, as well as to your state’s attorney General and better business bureau. any offer you receive that does not bear our company logo or corporate/customer service address or 800 numbers should not be considered approved by us. the only autHOriZeD inFOrMatiOn for Kitplanes is: toll free via telephone 1-800-622-1065, Dial america renewal telemarketing, or www.kitplanes.com/cs Our texas customer service center: 1-800-622-1065, pO box 8535, big sandy tX 75755 Or our corporate offices at: belvoir Media Group, llc. aviation publishing Group 535 connecticut ave norwalk ct 06854 should you have any questions at all about mail that you receive, please contact us at our website: www.kitplanes.com/cs or call us toll free to speak to customer service.

62 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes CHECKPOINTS Last Action Taken The title of this month’s column almost sounds ominous, but in reality it is a practice that I have used many times in all of my years of flying. In the last few months alone, I have exercised it twice, and in one case it truly saved me from taking a course of action that could have had a less-than-happy outcome. During our initial flight training we are constantly drilled in how to deal with emergencies, including everything from communications failures to engine stoppages. Really good flight schools have some sort of emergency scenario planned for every flight right up until the check ride, excluding solo flights, of course. That was a practice even when I Many checklists for general aviation aircraft have emergency procedures highlighted, learned to fly at Davis–Monthan Air Force which means the pilot should spend some time committing them to memory. Then Base in 1977. Even on my first solo flight, once the actions are taken during an actual emergency, refer to the checklist to verify completion of the items. the right window of the C-152 trainer popped open right as I lifted off. There includes a lot of failure scenarios. Multi- the feather position, and promptly pull- were no noise-cancelling headphones engine training is a constant barrage of ing the mixture control to idle cutoff. back then. In fact we didn’t use headsets engine failures. During my training for Unfortunately, this time the instructor at all! Yes, it was loud and distracting, but a multi-engine rating back in the ’70s, it did not guard the mixture levers, and I I just reached across the now-empty right was common practice for the instructor proceeded to pull the only remaining seat, closed the window, and continued to fail an engine at rotation by pulling mixture lever, which happened to be the flight. Truth be told, it wasn’t much the mixture back to idle cutoff. The stu- for the remaining good engine. Yep, it of a reach in the C-152. I later heard from dent was expected to identify the failed got kind of quiet, but luckily we had lots another instructor that it probably wasn’t engine, take the appropriate actions, and of runway left and no metal was bent. I an “accident” that the window popped continue the flight. A simulated engine never forgot that incident, and it had an open. Jerry, my instructor and the chief failure in a light twin right at rotation impact upon how I reacted to emergen- tower controller at the base, was known requires steps that need to done correctly cies as time progressed. The old adage to look for ways to surprise his students. and immediately. Most light twins cannot about “looking at your watch first” is a Good for him, as vigilance remains climb on one engine, and some can’t even good one, and I teach that approach ingrained to this day. I still remember my hold level flight on one engine. Decision- and have practiced it myself many times. first flight after achieving my Private Pilot making during these few critical seconds An engine failure at rotation probably certificate—I kept waiting for something needs to be deliberate and correct. doesn’t call for looking at your watch, but to happen, as every flight prior to it had During one particular training flight, I it can force you to slow down and take some kind of “emergency.” correctly identified the failed engine and deliberate actions. As most of you know, the training for proceeded to shut it down by closing the Today most multi-engine training pro- additional certificates and ratings also throttle, moving the propeller control to grams only simulate engine failures close

Vic is a Commercial Pilot, CFII with ASMEL/ASES ratings, an A&P, DAR, and EAA Technical Advi- sor and Flight Counselor. Passionately involved in aviation for over 40 years, he has built 11 aircraft and logged over 8700 hours in 72 different kinds of aircraft. Vic volunteers as a Young Vic Syracuse Eagle pilot and Angel Flight pilot. He chairs the EAA Homebuilt Council and is a member of EAA’s Board of Directors. He also has his own sport aviation business called Base Leg Aviation.

Photos: Vic Syracuse KITPLANES March 2018 63 Note the unlabeled knob next to the EFIS warn light. One might think it’s a volume knob. It turned out to be a servo-controlled oil cooler valve and almost lead to an unscheduled landing due to rapidly rising oil temps.

to the ground by creating a power con- until weather interfered. Flight planning dition that produces “zero” thrust, rather showed a total time en route of 14 hours. than completely cutting the fuel off. If the weather cooperated, this could be Simulator training for airlines also an easy couple of days. Unfortunately, by includes emergency scenarios in every the time we finished the inspection, test single session. Some of the scenarios flights, money transfers, and paperwork, require an action so immediate that it it was 3 o’clock in the afternoon, with is constantly practiced until it can be the temps hovering around 100° F. Not executed flawlessly. For some emer- exactly an optimum time for a flight in gencies, especially in the military and the southwest desert. airline industries, there are memory Luckily, it was a dry day, with no sum- items that need to be executed without mer afternoon cumulus, and the winds reference to a checklist. If you can’t pass weren’t very strong. RVs are good climb- the memory test, you don’t even get to ers, and eastbound out of Phoenix to the simulator! Albuquerque only requires climbing to 11,500 or 12,500 feet. We made it to What Did I Just Do? Albuquerque quite uneventfully, and Here’s another approach that has saved even the bumps were tolerable. There my bacon a couple of times: I stop and were some thunderstorms east of Albu- ask myself what was the last action taken. querque, which interfered with our Just a couple of months ago, I traveled planned next stop. However, Amarillo to Phoenix, Arizona, to perform a pre- looked good, and we made the deci- buy on an RV-9. The prospective buyer sion to continue, with the idea being we was meeting me there in the hope that would arrive in Amarillo about 30 min- it would work out, and we could both utes after sunset. The aircraft was night then fly back to Bridgeport, Connecticut. legal, but not IFR legal, and I don’t like I had two days in my schedule that could being out over the desert at night any- work, and we agreed that we would try way. Thirty minutes after sunset is still to at least get it as far east as possible light enough for me.

64 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes You know how every incident or acci- I was annoyed at the seller though, jumped out at me—that unlabeled dent has a chain? Well, this is where this and a phone call that night when we knob. I had been playing with it earlier chain starts—pressure to try and get 4 landed confirmed he knew about the to see if it did anything. Hmm. I hadn’t hours of flying in on day one, such that problem. He hadn’t flown it at night in figured out what its function was, so the 10 hours remaining for day two was over a year, he said, so he had forgotten I let it go. On a hunch I rotated it com- achievable. In fact, the weather was about it. Quite candidly, this problem pletely in the opposite direction from severe clear from Amarillo to Bridgeport. could be duplicated during the day by its current position. Within 15–20 sec- So, off we headed, and as we flew east switching on the nav lights—a whole lot onds the oil temp immediately started the skies were getting darker. The young, less stressful for sure! decreasing and continued rather rapidly inexperienced pilot in the left seat kept all the way back to 180°! Boy, was I going telling me it was getting dark due to the What’s This Knob For? to have a discussion when I landed. I clouds. I kept saying I had been flying The second recent incident occurred was pretty certain this knob was not long enough to recognize the dark of when I was asked to relocate an RV-10 there when I licensed the airplane, as night, and it looked like night to me. The from Destin, Florida, to Atlanta due to unlabeled controls are a pet peeve of ceilings at Amarillo were now lowering an approaching hurricane. Upon arrival mine. Sure enough, the builder admit- to an unforecasted 1000 feet, and it was at Destin, I had the tanks topped (I won’t ted he had installed a servo-controlled clearly dark. Really dark. Why? Because fly an unknown airplane without top- oil cooler valve recently and had forgot- we were now 1 hour past sunset. The ping the tanks) and familiarized myself ten to label it. light bulb finally went off in my head that with the cockpit layout. I had actually There’s one other lesson in both of we had crossed into the Central time licensed this airplane as a DAR a number these for all of us who build airplanes. zone, and somehow I had missed that in of years ago, so I was comfortable with Yes, we get to personalize them, but we my flight planning. I wasn’t happy, but the build quality. Only one thing caught should build them and label things such no big deal, as we were only about 30 my eye, and that was an indicator light that another pilot can get in it and safely minutes from our destination. We had on the panel labeled “EFIS Warn” and fly it. It’s supposed to be fun. Let’s leave been following I-40 since we left Albu- an unlabeled knob next to it that had the emergency scenarios to the flight querque, and it was well lit due to the all of the appearances of a volume con- training flights.J amount of vehicular traffic. trol or dimmer function. The owner was Then it happened. I don’t remember inaccessible, as he was on a sailboat in who noticed it first, but both the oil pres- the Gulf behind the hurricane. With sure and the oil temperature gauges were everything else good to go, the RV-6 showing a steady climb to the top of the pilot who brought me to Destin and I gauges. It’s not a good feeling to see that departed as a two-ship. Oil temp rose over the desert at night. They both contin- normally during the climb and then ued to climb until they were off-scale high, leveled off and proceeded to cool back and the discussions started regarding a down to around 183° once in level flight precautionary landing. I did not like the at 7500 feet. About 30 minutes into the potential outcome of that scenario at all. flight, I noticed the oil temp was starting Two thoughts jumped into my head: first, to steadily climb, about 1° every 15–20 this engine had been running fine all day, seconds. When it got to 210°, I radioed for at least 3.5 hours and had no history the RV-6 that I might make a precaution- of problems, and I had just given it a thor- ary landing to check out a rapidly rising ough inspection back in Phoenix. Second, oil temp indication. The difference with high oil temp is usually accompanied by this scenario is that the oil pressure was a decrease in oil pressure, not an increase. decreasing, as it should with elevated My next thought was, “What was the last oil temps. It was clear to me that the thing I did?” and I even said it out loud. I oil really was getting warmer. Perhaps remembered I had turned on the navi- a leak? The last thing I wanted to do gation lights about 30 minutes ago. So, I was bend an airplane I was entrusted to turned them off and, sure enough, both move to safety. gauges returned to the normal readings Well, again I asked myself what was we had seen all day. I could duplicate it by the last action taken? I looked around cycling the nav-light switch. What a relief! the cockpit and verified that all of the Problem solved. It was a wiring problem, engine controls were in the same posi- probably a bad or daisy-chained ground. I tion. I scanned the panel, and as I began have seen those problems before. to turn toward the nearest airport, it

KITPLANES March 2018 65 COMPLETIONS Robert Anderson’s RV-8 After many years of both building and not building (about 50/50), N184GC first flew on April 22, 2015 from Santa Fe (New Mexico) Municipal Airport. Making the first flight in the airplane I built was probably the most rewarding experience I’ve had in my life. N184GC is powered by a Lycoming O-360-A1A with dual P-Mags and a Catto three-blade prop. The paint scheme is my own design, but I left the paint application to the professionals. My airplane was awarded Best Homebuilt at the 2016 Land of Enchantment Fly-in; First Place, Custom-Built Metal, and Grand Champion at the 2017 Copperstate Fly-in; Second place, Custom-Built Metal at Copperstate 2016; and Kit-Built Outstanding Workmanship at EAA AirVenture 2017. Santa Fe, New Mexico [email protected]

John Albritton’s Eze Jet This day was a long time coming for me (about 12 years), but at last I’m flying my own jet! The engine is a GE T58-8 turbine, and the airframe has been highly customized. For example, the winglets were removed from the wings to a location on the aft fuselage. In the new location, the airplane feels easier to roll—and it looks cool, too! I also wanted all three wheels to retract, not just the nose gear like a typical Long-EZ. Another challenge were the air intakes for the engine. Once they were in the location where I wanted them, the bends were too great to get maximum performance from the engine. The only viable solution was to run them into the area where the back seat would normally be. That’s OK because I enjoy flying solo and it allowed room for an extra fuel tank—but it also required major modifications to the flight control system. Many thanks to Robert, Mike, Steve, and Terry at Jet Guys for making the impossible…possible! Oakland, Tennessee [email protected]

Rich Macrafic’s RV-7A After a 12-year build, RV-7A N4956T flew for the first time on Octo- ber 9, 2017 from KRST (Rochester, Minnesota). Everybody talks about the “RV grin” after that first flight. For me, that came on the second flight. The first one was approached with trepi- dation, caused by the combination of a new plane that had never flown and a pilot (me) that had only six hours of transition training (albeit excellent training) under my belt. The flight ended with, I’ll admit, a few tears—tears of relief, pride, joy, and accomplishment. OK, it also ended with a bottle of champagne with my co-builder and wife, Cindy. We extend a sincere, heartfelt thanks for all the eager and knowl- edgeable assistance we received from so many fronts as we made our way forward on this epic journey. To all of you, thanks for the memories. You are all a part of the heart and soul of N4956T and have a place in our memories and hearts for a lifetime. Rochester, Minnesota [email protected] J BUILDERS SHARE THEIR SUCCESSES Submissions to “Completions” should include a description (250 words maximum) of the project and the finished aircraft. Also include a digital image of the aircraft. Minimum digital image size is 1500 pixels wide x 900 pixels high (5 x 3-inch print size at 300 dpi). Other builders may want to contact you by email, but let us know if you prefer not to have your email address published. Email text and photos to [email protected] with a subject line of “Completions.” Additional information can be found at www.kitplanes.com/completions.

66 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes BACK ISSUES LIST OF ADVERTISERS Please tell them you saw their ad in KITPLANES® Magazine. O O NEW eBOOK KITPLANES® interactive makes it quick and easy for you to receive instant eBook download is exactly the information about products or services directly from our advertisers’ websites. same magazine as on the newsstand. ➥ Go to: www.kitplanes.com/links for a virtual shopping tour via links to their The difference is: websites. ➥ Call the phone numbers listed below and be sure to tell them you saw their ad you get it now! in KITPLANES® Magazine. & no shipping costs for Advertiser page # telephone Advertiser page # telephone e-books! Aircraft Spruce & Specialty CV4 877-4SPRUCE Carlson Aircraft 69 330-426-3934

(a big savings for our international customers) Avemco Insurance Company CV3 888-241-7890 Crow Enterprises 68 714-879-5970 eBooks download as a single, full size, Better Aircraft Fabric 25 907-229-6792 Custom Welding Products 69 702-306-3590 full color .pdf document which you can view on your desktop, laptop or tablet computer. California Power Systems 65 800-AIRWOLF Falconar Avia Inc 70 780-465-2024 PDF eMagazine issues are fully searchable Dynon Avionics CV2 425-402-0433 Flight Data Systems 68 831-325-3131 and are compatible with all Adobe Acrobat functions such as highlighting, page notes Garmin International 5 913-397-8200 Flight Grip 68 800-204-7625 and spoken word audio. Grand Rapids Technologies 33 616-245-7700 Glen-L 69 888-700-5007 O Individual monthly issues are $6.95 O A compiled Aircraft Buyer’s Guide Grand Rapids Technologies 75 616-245-7700 Grove Aircraft 68 619-562-1268 is $12.95 Kitplanes® Bookstore 64 970-726-5111 Homebuilt Help 71 See Advertisement

Visit: Progressive Aerodyne 75 352-253-0108 INFINITY Aerospace 70 See Advertisement www.kitplanesbooks.com to order SDS Aero Products 25 403-671-4015 Innovator Technologies 69 403-669-3101 Sonex Aircraft, LLC 25 920-231-8297 Kuntzleman Electronics Inc. 68 610-326-9068 ❏ February 2018 2018 Engine Buyer’s Guide, Arctic to Antarctic in Sky Polaris RV-8, All About Spars Stewart Systems 75 888-356-7659 northwest Aviation Services 71 208-435-4002 ❏ January 2018 Zenith STOL CH 750 SD, Easy Wheelpant Repair, Langeaire Aircraft Parts, Returning to Flying Van’s Aircraft 3 See Advertisement Osprey Aircraft 70 See Advertisement ❏ December 2017 2018 Homebuilt Aircraft Directory, KIS TR-1, Lithium Batteries, Taking Over a Project Performance Propellers 71 713-417-2519 ❏ November 2017 Van’s RV-12iS, Constant-Speed Propellers, Builders’ Marketplace Zenith Aircraft’s 25th Anniversary AeroMomentum Aircraft Engines 70 772-240-2266 RAM Aircraft 71 254-752-8381 ❏ October 2017 Murphy Radical, Modified RANS S-9, Prepping for the DAR, Landing Gear Guru Aerotrek Aircraft 71 812-384-4972 Recreational Power Engineering 69 800-583-3306 ❏ September 2017 Kitfox S7 STI, Ly-Con Cryogenic Treatments, Reducing Drag, Engine Swap, Optical Tach Airflow Performance 69 864-576-4512 Simplex Aero 69 801-830-0612 ❏ August 2017 Marvelous Mustangs, Latest on ADS-B, Vortex Generators, Avionics Cooling Fan Bearhawk Aircraft 70 877-528-4776 Softie Parachutes 71 360-435-7220 ❏ July 2017 Tech-built Skyotë, Thundering Mustangs, Alpha Systems AoA, Judging at EAA AirVenture Bede Corp. 71 See Advertisement Sportsman’s Market 69 800-SPORTYS ❏ June 2017 Cygnet, Glastar Amphibian, Garmin School, Bearhawk LSA, Factory Pilots, Fuel Shutoff Valve Better Half VW 69 281-383-0113 WhirlWind Propellers 68 619-562-3725 ❏ May 2017 Sonex Waiex-B, Supercharging, Control Locks, Making Tapered Ribs, Effects of Ignition Advance

KITPLANES March 2018 67

BUILDERS’ MARKETPLACE GROUND ADJUSTABLE CUSTOMIZE OUR GRIP COMPOSITE PROPELLERS FOR YOUR AIRCRAFT LANDING GEAR Your Complete Source Easy Installation • ROTAX for Wheels, Brakes • JABIRU Comfortable & Landing Gear Rocker (shown) or push button trigger style • CONTINENTAL Thumb Switches: • LYCOMING Push Button, Toggle and/or 4-Way Trim Fit to 5/8" thru 1-1/8" sticks Next day shipping for virtually any conﬁ guration you desire.

Factory Direct 619-562-3725 www.groveaircraft.com 812 Jacquelyn St. • Milton-Freewater, Oregon 97862 Grove 1800 Joe Crosson Dr. www.whirlwindpropellers.com 800-204-7625 • 541-938-0533 • Fax: 541-938-7242 El Cajon, CA 92020 Aircraft Landing Gear Systems Inc. 619.562.1268

The must-read for the GA Community! Log-in for FREE News Alerts www.avweb.com/kit

68 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes 1204-8 Airflow 1/10/05 2:35 PM Page 1

Aircraft Multi-point Fuel Injection • Operates all engines from 65 to 800 HP • Applications for V6/V8 engines • Manual Mixture Control • Bolt on Kits for Lycoming Engines • No Carburetor heat required • Instant throttle response • All Mechanical, No Electronics • Increases mid-range HP • Approved for Aerobatic use • Compatible with all Fuels • Precise Fuel Metering under all conditions

111 Airflow Drive Spartanburg, SC 29306 (864) 576-4512 (864) 576-0201 (Fax) www.airflowperformance.com Email: [email protected]

HIRTH AIRCRAFT ENGINES 15 thru 110 hp. 1000 hour rated TBO. One year warranty. Share Your Enthusiasm for Sales, service, and parts. Highest power to weight ratio in the industry. BlueMax 2-cycle aviation oil. Contact: RECREATIONAL POWER ENGINEERING 5479 East County Rd. 38, Tiffin, Ohio 44883 Tel: 800-583-3306 • Fax: 419-585-6004. Visit us on the web at www.recpower.com

TURBO HEAT Cabin Heat Muff introduced at Oshkosh Efficient • Affordable • Easy to Install Follow us on Facebook at (702) 306-3590 www.facebook.com/kitplanes www.customweldingproducts.com

® INTRODUCING THE LEGAL EAGLE XL Have You Seen Us Lately? The KITPLANES® website is now better than ever! KITPLANES.COM is YOUR guide to the most comprehensive homebuilt information available, A NEW ultralight with a larger cockpit area. Empty 246 lbs., and access to our archives and aircraft database wing area 120 sq. ft. Gross wt. of 575 lbs. STOL. Powered by Better Half VW aero engine. Wood wings, steel fuselage, are FREE to registered subscribers! and aluminum tank construction. Airplane plans $80. Engine plans $20. 4 helpful DVDs, $25 each. Highlights: Contact L.E. Milholland for plans, DVDs and wing and fuselage parts. Work: 281-375-5453, Cell: 281-785-3777. • Revamped and expanded Aircraft Buyer’s Contact John Bolding for materials package and Guide for quicker, better search results welded fuselages. 281-383-0113. • All New Classiﬁ ed Ads section for deals on aircraft and accessories SPARS, STREAMLINE STRUTS, RIBS • Unlimited access to back issues as an easy- 6061T6 - EXTRUDED - CERTIFIED ANALYSIS to-use, tablet-friendly downloadable PDF SPARS - 6 sections - 3” to 6 5/8” STRUTS - Large, Small, Heavy Duty, Jury RIBS - Stc’d, Experimental, Custom It’s easy to register. Just visit WWW.KITPLANES.COM and click on Write/Call for free info: GET WEB ACCESS. CARLSON AIRCRAFT INC. 330-426-3934 • [email protected] “Like” us on Facebook, follow us on Twitter and get www.carlsonaircraft.com an RSS feed from our Newsline

KITPLANES March 2018 69

BUILDERS’ MARKETPLACE

PLANS - KITS - PARTS “OSPREY 2” AMPHIBIAN

2/3 Mustang F12 Cruiser and 10 other all wood designs

Info Packs $10/ea + $4 Postage 2-Place, all wood, 12 sec. water take-off, full HIPEC Covering System - no ribstitching, no taping. builder support, Oshkosh award winner. Info Pak Lo cost — Lo labor — proven $14 ($17 overseas), Plans $250 ($290 overseas). www.falconaravia.com OSPREY AIRCRAFT Email: [email protected] 3741 El Ricon Way, Sacramento, CA 95864 FALCONAR AVIA INC. Ph: 780-465-2024 Email: [email protected]

Working with a Tight Budget?

Builders’ Marketplace reaches tens of thousands of homebuilders and pilots who are eager to buy new products and services. Call 805-382-3363 or email: [email protected]

70 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes Buy a Plane or Sell a Plane with a FREE ad online.

406 & 121.5 ELT Tester • Affordable and effective • Does a comprehensive test • Simple to use • Tests all COSPAS SARSAT • Provides Pass/Fail indication Beacons • Displays hex indentiﬁ cation • Uses readily-available • Indentiﬁ es beacon type AA batteries $648.00 Plus Shipping & Handling (208) 435-4002

P.O. Box 2466 Oroﬁ no, Idaho 83544 www.beacon-tester.com

Can’t Get Enough ? Get the latest. Follow us on Twitter at #Kitplanes.

Any individual may post a flying homebuilt or partial project complete with photos at no cost for quick global response.

www.kitplanes.com/classifieds

KITPLANES March 2018 71 Repairman certificate eligibility, ELSA mods, flying at civil twilight, fuel cap engraving. By Mel Asberry Question: I recently purchased primary builder at the original certifica- unable to get a definitive answer to an original design homebuilt air- tion of the aircraft. this question: Does day VFR include plane loosely based on a J-4 Cub Replacing the engine is considered civil twilight? with two-place side-by-side seating. a major change and would normally Answer: Thanks for your question. The builder/designer obtained an require a new Phase I flight test, but since FAR Part 61.315(b)(5) states that you N-number and flew off the 40 hours. the aircraft is still in the original Phase I may not fly “at night” while exercis- At that point he decided to replace period, that will not be necessary. ing the privileges of a Sport Pilot. FAR the 90-hp Continental engine with Anyone may perform maintenance, Part 1.1 defines “night” as “the time a new Corvair he assembled him- and even modifications, to an Experi- between the end of evening civil twi- self. He did not get the aircraft fly- mental Amateur-Built aircraft, so you light and the beginning of morning ing with the new engine. are good to go in that respect. How- civil twilight, as published in the Air I need to complete the engine ever, you will not be able to perform Almanac, converted to local time.” So, installation, reinstall the wings, and the annual condition inspection. Only it looks to me like you are good to go do many other repairs to make the the original builder, if he has obtained during civil twilight. aircraft airworthy. I have not yet the repairman certificate, or a certifi- Question: I plan to get my fuel taken the course offered by Rain- cated A&P mechanic may perform the caps engraved, but I’m not exactly bow Aviation, but plan to do so very condition inspection required by your sure what information is required. soon. Can I do this necessary work operating limitations. I’m pretty sure I need to include myself, make the logbook entries, Question: My ELSA RV-12 just capacity and type of fuel, but is and in the future do the annual con- passed its airworthiness inspection. there anything else? Also, what dition inspections myself? Do I need to finish Phase 1 testing happens when 100LL goes away? Answer: As I understand, your air- before I can make modifications? Should I have the wording on the craft is certificated as an Experimental/ Answer: No. An ELSA can be modi- caps say something like “100LL or Amateur-Built. It will remain an E/A-B fied immediately after certification. Equivalent Octane”? throughout its life. It cannot be con- Question: I have a Private Pilot Answer: Only fuel tank capacity and verted to a Light Sport Aircraft. There- license and have let my 3rd-class minimum octane rating are required. fore the Rainbow Aviation course will medical expire; therefore, I exer- Lead content has no bearing on this. J be of no help in getting the repairman cise the privileges of a Sport Pilot. certificate for this aircraft. The only My aircraft is licensed as an E/A- Please send your questions for DAR path to qualify for a repairman certifi- B, and it meets the definition of a Asberry to [email protected] with cate for this aircraft is to be listed as a Light Sport Aircraft. I have been “Ask the DAR” in the subject line.

72 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes WIND TUNNEL Design Process, Part 4: More About Speed Last month we took a look at how the required cruise speed affects the cost and complexity of the airplane. As cruise speed increases, the airplane requires more power, burns more fuel, and becomes more complex as retractable landing gear, high lift systems, and constant-speed propellers become necessary to provide the required performance. With this in mind, when we are setting our design requirements, it’s important to ask the question, “How fast do we For a lot of typical private flying, planes like the Sling 2 LSA offer an effective combination really need (want) this airplane to go?” of performance and price. (Photo: Kevin Wing) We usually look at cruise speed in the context of flying cross-country. Unless Speed and Range of action of the airplane. This is particu- the airplane is intended for racing or How fast we need to fly is a direct func- larly true for private pilots since much to set an absolute record, sheer speed tion of how far we want to go. The of our flying consists of single-day out- in and of itself has little value. What is faster the airplane is, the farther it can and-back excursions. important is how fast we need to fly to go in a given time. For most pilots, With this in mind, let’s take a look at how get from A to B effectively. cruise speed defines the useful radius cruise speed affects time and distance. Figure 1 shows distance vs. time for several values of cruise speed for ranges up to 200 miles in zero wind. For this example, the airplane first climbs to cruising attitude at 70% of cruise speed and then cruises at constant speed there- after. All of the airplanes have the same rate of climb and cruise at the same attitude. Note also that speed is in knots, but distance over the ground is shown in statute miles. Let’s look first at the time to cover 100 miles, which is a common day-trip radius of action. Our slowest (60-knot) airplane takes 90 minutes to do this trip. Increasing speed to 80 knots (Cessna 150-ish speed) reduces this to 68 minutes. Moving up to the Light-Sport maximum cruise speed of 120 knots cuts this trip to 46 minutes. For this short range, as we get faster Figure 1: For very short trips, the time en route isn’t all that different for fast and slow than this we begin to hit diminish- planes. But for long trips, the difference is significant. ing returns, particularly if we take into

is a Technical Fellow for Northrop Grumman’s Advanced Design organization. A private pilot with single engine and glider ratings, Barnaby has been involved in the design of Barnaby Wainfan unconventional airplanes including canards, joined wings, flying wings, and some too strange to fall into any known category.

KITPLANES March 2018 73 account the time to fly the traffic pattern and taxi in. Going from 120 knots to 160 knots only saves about 10 minutes. This means that if they take off simultane- ously, the 120-knot airplane will be entering the downwind at about the same time that the 160-knot airplane arrives at the destination airport ramp. A further increase to 200 knots only saves an additional 6 minutes. Moving out to a 200-mile radius, the first thing we can see is that the trip in the 60-knot airplane is now a 3-hour evolution. Our 80-knot machine gets us there in about 2 hours and 15 minutes. Our Light Sport (120-knot) ride does this mission in 1½ hours. At this range, the 160 knot airplane reduces travel time by 22 minutes over the Light Sport, which might start to look worthwhile to some pilots. Even at 200 miles, the benefit of The slower the airplane flies, the more a given headwind increases mission time. In increasing speed to 200 knots is rela- these examples, solid lines represent zero wind and dashed lines represent flying into a 15-knot headwind. tively small. At longer ranges, additional speed bringing the time down to 2½ hours, reduces the over-the-ground speed of a begins to pay off. At 450 miles, which while a 200 knot cruise reduces the 60-knot airplane by 25%, while the same is about the maximum range of many mission time to 2 hours. wind causes a 12½% penalty for a 120- single-engine airplanes, going fast starts At this range, the faster cruise speeds knot airplane, and a 7½% penalty for a to be much more desirable. At this range, provide a very desirable improvement in 200-knot airplane. For the faster airplane, the 60-knot airplane is a complete non- mission performance. the wind costs a smaller percentage starter. The 80-knot airplane can do the of the already-shorter zero-wind mis- mission, but it takes 5 hours. While this Wind sion. Accordingly, a given headwind will is doable, if tedious, for a one-way trip, it So far, we have only looked at zero-wind increase the flight time much more for means that there is no reasonable chance conditions. Unfortunately, the wind is a slower airplane than a faster one, and of a same-day out-and-back excursion. rarely zero and many flights are into a this penalty will rise rapidly with slower The 120-knot airplane takes 3 hours significant headwind that reduces the cruise speed. and 20 minutes to do the 450 miles. This airplane’s speed over the ground. This effect is illustrated in Figure 2. is long enough to be a significant under- The slower the airplane flies, the more For each cruise speed, the solid line taking, but within the limits of what most a given headwind increases mission time. represents the zero-wind case, while pilots would be willing to undertake at This effect is nonlinear because a given the dashed line represents flying into a least occasionally. wind speed is a greater percentage of a 15-knot headwind. Moving up to 160 knots shaves almost slower cruise speed than of a faster cruise On our 100-mile day excursion, the an hour off the 450-mile mission, speed. For example, a 15-knot headwind 15-knot headwind increases the mission time for the 60-knot airplane by 25 minutes. The penalty for the 80-knot airplane is about 15 minutes, while the 120- knot airplane is only delayed by about 5 minutes, and the delay for the 200-knot airplane is very small indeed. As the range increases, so does the time penalty for the headwind. If mission requirements for the airplane include routinely flying against significant winds, the range at which flying faster begins to With retractable gear, constant-speed props, and cruise speeds in the 200-knot range, pay off is shorter than it is for the zero- the Velocity V-Twin was designed for long cross-countries. (Photo: Richard VanderMeulen) wind case.

74 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes A Few Conclusions From the above, we can begin to see some natural breakpoints for our specified cruise speed. The first of these is that if the airplane is slower than about 80 knots, its cross-country capability is minimal. It’s suitable for local, recreational flying only. 80 knots seems to be about the lower end of the range of cruise speed for useful cross-country capability, but increasing speed to about 120 knots yields a meaningful improvement for day excursions. The 120-knot airplane has a significantly larger radius of operation for single-day VFR out-and-back flying. It’s only when the required range gets significantly above 200 miles that increasing cruise speed beyond the Light Sport limit of 120 knots really begins to pay off. Looking at the conclusions above, it’s ...and leave your engine not surprising that a large number of monitoring to EIS. popular types have cruise speeds that Trusted with everything from 2-strokes fall in the 80- to 120-knot range. In fact, to turbines for over two decades. the certified airplane types that have sold the most units in history essentially all fall in this performance band. This also makes sense from a cost- FLY IT effectiveness viewpoint. This speed range like you stole it... is where an airplane with fixed landing gear and a fixed-pitch propeller works well. Cost is a major concern for most www.grtavionics.com • (616) 245-7700 private pilots. The fixed-gear, fixed-pitch Proud sponsor of Tiger Airshows and airplane “thief” extraordinaire, Hotwire Harry! airplane costs less to buy, less to maintain, and probably burns less fuel than a higher powered retractable with a constant- speed propeller. Given the minimal time value of higher cruise speed for a lot of typical private flying, these airplanes offer the most cost-effective combination of performance and price for many aviators. It also shows that the 120-knot maximum speed specified in the U.S. Light Sport rules is a sensible choice. It’s a speed that is achievable by simple airplanes that can be safely operated by Sport Pilots, which is also fast enough to make the airplanes effective for the kind of flying the majority of Sport Pilots do. Finally, as attractive as the idea of a really fast airplane is, the added cost and complexity required to get that alluring top speed is only really useful to the pilot if the airplane will be used primarily for longer range cross-country travel. J

KITPLANES March 2018 75 AERO’LECTRICS Spread Those Sheets I’m kind of loose with my engineering and teaching. I don’t have a lot of hard- and-fast rules. One of them is that any time I have a calculation that I’m going to do more than twice, or that takes more than one or two steps, it gets reduced to a spreadsheet. I cannot calculate (you should pardon the expression) how much time it has saved me to do a voltage divider or a wire temperature estima- tion to have done the work (sometimes an hour or so on the spreadsheet) that saves literally lots of hours in the field. That and spreadsheets allow me to print out charts that I use in the machine shop and post them near the machine on which they are used. 4-40 clearance hole? Easy —#31 drill at 0.120 inch, and if I want to tap the sheet behind it then a #43 at 0.089 will do just fine. This month let me take you through Almost everything you need to know about machine screws is in machscrw.xls. a few of the spreadsheets posted at my college website. You can download a a. I’ve got this chart on the wall behind a. Lots of data with reference to sea zip file at https://tinyurl.com/ya9a6dxn. my drill press in a frame to keep the level (0 msl). However, here we It contains a few dozen spreadsheets, cutting oil and metal shavings from introduce the convention of “E to some of them incomprehensible unless destroying it from time to time. the power.” This may take some you are familiar with the subject, but you b. As the note at the bottom says, in thought if you’ve never seen it are certainly free to use them if you can “soft” aluminum (say, 5052H32 or before. Let’s take, for example, the figure them out. the like) cut yourself some slack density of air at sea level. It says I’m going to take from them what I and make the drill bit a size or two that it is 76.5E-3 pounds per cubic think is the most usable information larger. I regularly go to #42 (0.093) foot. E-3 means that the numbers and try to explain them so that you can for 4-40 with no ill effects. in front of it are multiplied by 10-3, use them. 2. Second is altitude.xls. You may find which we remember from high 1. First of all is machscrw.xls. Here you this useful to figure out whether school algebra as divided by 1000. will find all machine screws from #0 or not you are operating in what is So, the actual value of the density is through ¼ inch, everything from called the “standard atmosphere.” 0.0765 pounds per cubic foot. threads per inch (both NC and NF), Temperatures or pressures may be b. Get this convention down now, clearance drills, tap drills, head sizes different from what you are currently because it is going to be used a for round, flat, and fillister heads, hex testing your airplane in, and it may whole bunch in future articles. nut sizes, and washer outside diam- explain some differences in the data 3. You may findohmslaw.xls useful if eter, inside diameter, and thickness. that you are recording. you have to convert from power to

is the chief avioniker at RST Engineering. He answers avionics questions in the internet newsgroup www.pilotsofamerica.com–Maintenance. His technical advisor, Cyndi Weir, got her Masters degree in English and Journalism and keeps Jim on the straight and narrow. Check out their Jim Weir website at www.rst-engr.com/kitplanes for previous articles and supplements.

76 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes resistors to current to voltage on a regular basis. a. Here we introduce a whole new concept. You fill in the data in the green boxes and the answers come up in the orange boxes. b. Example—you have a 150-watt landing light on a 12-volt aircraft. How much current does it draw? You know E (electromotive force, or volts = 12 volts) and watts You may find altitude.xls useful to figure out whether or not you are operating in (power = 150 watts), so you have to “standard atmosphere.” either use a fuse or circuit-breaker for a current of (I) = 12.5 amperes (“amps”) (plus whatever overcur- rent or safety factor you wish). Me? That’s a 15-amp breaker. 4. Here is the granddaddy of them all, and I have this copied into my engi- Use ohmslaw.xls to convert from power to resistors to current to voltage. neering binder that I carry with me nearly all the time. wirecalc.xls is the ultimate wire table reference and calculator. Ten years ago it was a neat spreadsheet; today they’d probably call it an “app.” Sigh. a. Yes, it is a wire table. It is the most complete wire table I’ve ever seen. Not many wire tables give fusing current, bundle current, or breaking strength. b. Fusing current is the current at which the wire will melt. c. Bundle current is the current recommended for a wire in a bundle of wires that may or may not be run to the maximum current of each wire. It is extremely conser- vative and may be derated (in my personal experience) by a factor of 2:1 without any problems. This is my personal opinion; your mileage may vary. Coming up? If you will recall in the last three articles, I’ve taken you through the mill on voltage regulators. I’d like to then take you through a “theory reduced to practice” on a lamp dimmer using all the techniques that I’ve used in these articles. Then I’d like to take you through the “anatomy of an ADS-B installation” that I’ve done in the RST Engineering C-182 heavy that you might want to consider prior to 2020. From there? Who knows; certainly not I. Not many wire tables give fusing current, bundle current, or breaking strength, but Until then…stay tuned… J wirecalc.xls does.

Photos: Jim Weir KITPLANES March 2018 77 REAR COCKPIT Layoffs, I’ve Had A Few Consider the lowly nut plate. Funny looking things, maybe even ugly. Inex- pensive. Pretty much falls under the “who cares” category, and for sure you won’t take her home if you go on about how much you love your nut plates. But don’t put a nut plate where you should, and you won’t have time to hang out in bars in the first place. You’ll be in your hangar instead, trying to stick an 11/32-inch nut onto a glob of masking tape wrapped to a length of rusty coat hangar long enough to snake into position and praying the screw doesn’t knock it off. Nut plates, like many small things, matter. I’m confident saying that, as several times I’ve had my aviating curtailed for significant periods because, in part, work on my air buggy was mired in a bottomless morass of under-engineered, hurriedly put together stuff that defied maintenance. And if assembling a Tab A into Slot B kit aircraft seems a chal- Easy maintenance matters. Taking the time to fit nut plates now instead of fumbling with lenge, try reinventing a rag-and-tube screws, nuts, and washers later is a smart building decision. homebuilt once it’s been put together and flying. It’s ship-in-a-bottle modeling page of that little tome, which is far too If the Feds allow us our folly for “edu- at its most tedious. long away from the airport. cation and recreation,” I at least got one Of course, I must admit my first There followed some rented Cessnas, heck of an education out of it. aviation sabbatical was entirely self- then the rather vertical jump to the Star- Next came a few years of actually fly- inflicted and came about from the old duster, followed by the 14-month gap ing my homebuilt, followed by the real- racer’s nemesis, hardening of the wal- spent on the ’duster’s first condition ization that those engine instruments let. Having learned aviation during my inspection. That’s when I learned why weren’t lying, and adding a quart of oil school years, my first job/early matri- they’re called annuals: because it takes every two hours wasn’t normal. Time to monial phase was pleasantly whiled on at least a year to get through them. It’s rebuild the ol’ 540. whether to float the water or electric bill also where I started my appreciation for that month. Then came a couple years nut plates. And service loops in wiring. Grounded spent—and that’s the perfect word— Or Adel clamps on control cables, wire Now, if you didn’t know how to hang racing ground iron, plus some organic ties made in the USA, inspection holes, by your financial socks before, get- human cloning activity before redis- fuel valves that cost more than $35 and ting on a first-name basis with the covering my logbook in the hall closet. didn’t once serve as Victorian water taps, engine shop will teach you patience. There’s a six-year span covered in one plus sheet metal thicker than .016 inch. In my case it was six and a half years

Pumping avgas and waxing flight school airplanes got Tom into general aviation in 1973, but the lure of racing cars and motorcycles sent him down a motor journalism career heavy on Tom Wilson engines and racing. Today he still writes for peanuts and flies for fun.

78 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes between shutting down in front of the Flying Again And they did after the much longer hangar and firing it back up again. And At the end of the first 14-month Star- six-year layoff for the engine over- you can bet there were nut plates in the duster layoff, I had but 36 hours in type haul. Again there was no instructor totally new firewall-forward overhaul. and a bare 44 hours total tailwheel time. handy, but this time there were over While the mechanical details learned Putting an instructor in the front seat 180 hours in type logged. Still, reason in all this were important, the real lesson sure seemed intelligent for the first flight said go find an instructor, and the little was the insidiousness of downtimes. Life after the condition inspection, but just voice was uncharacteristically pretty turns out to be a short flight, and coax- as with my transition training two years quiet. But when faintly heard it said, ing 11/32-inch nuts into position with a earlier, there wasn’t a qualified instruc- “Yeah, some dual in something besides coat hangar and masking tape is not the tor in sight. Ultimately I picked a quiet, a 152 would help, but you’ll be okay.” best of what aviation or kit building has beautifully clear, windless morning to And there’s the real-world rub of these to offer. Better to take the time in the see just how much I remembered of this situations: Absolutely yes, meaning- beginning, and put a nut plate in that flying business. ful dual would be good. But typically hard-to-reach spot, both for yourself Under “remarks” in my logbook for such is not realistically available, and and the next guy. that date, it starts with “Wow!” It took it’s up to the owner to make the nearly Downtime turns out to be expen- two approaches to stick a landing; the impossible self-evaluation and decide sive in more than squandered time, first was perfect but my brain, flapping whether to go it alone. The stats sug- too. While my engine sat in pieces and like the red rag at the end of the load, gest we don’t get this one right much I pecked at a keyboard to pay to put it simply wasn’t ready for the runway rush- of the time. back together, there was hangar rent to ing up, and involuntarily the throttle Certainly the additional pilot pro- pay. Six plus years of what amounted to went in. The second time was equally gram, which allows two people in the storing aviation wreckage added up to on track, on speed, and almost as over- cockpit for Phase I, is a godsend. But easily more than what the engineless whelming, but the ego overruled the id the challenge still seems to be a lack of airframe was worth. It was also six years long enough to get us through the blind qualified mentors when and where you of ozone eating the bungees, radios flare and touchdown. need them. decaying, and me keeping one step It was a good shove out of the com- Probably the best advice is to avoid ahead of the mice. fort zone, but was it really right to jump layoffs, even if it’s to stop building for Perhaps most appropriately for in after such a layoff? The little voice a week of intensive flying in basic air- KITPLANES® readers, downtime proves that’s never wrong wasn’t totally sure, craft—ultimately it might avoid some piloting skills are perishable. Whether but leaned toward finding an instructor rebuilding of whatever it is you are build- you’re building or repairing doesn’t mat- should similar conditions reappear. ing. And don’t forget the nut plates. J ter; when you’re not flying, you’re not refreshing, or better yet, updating, those hard-earned stick and rudder skills, not to mention instrument proficiency. Back when I was flying 172s, this was not ter- ribly difficult to rectify; I bought a cur- Unairworthy rent AIM and read until it rendered me unconscious nightly, then took a BFR. Throttle After that it was merely paying more attention than usual in the local area as Interference the finer points came back. A slight sticking was Getting back into the Starduster was noticed when the throttle was moved to another issue, and again, this is more the full open position. appropriate to KITPLANES® readers, as Further investigation the hot-rodded biplane’s quicker takeoff, revealed that the nut wider performance envelope and, above and cotter key were all, its high-drag engine-off “glide” (think catching on the fuel mine-shaft accident) reward assertive servo hose and had piloting and can punish the slow or almost cut completely timid. There’s absolutely nothing super- through the firesleeve. human about piloting such an aircraft; Rerouting the fuel it’s something nearly anyone can learn servo hose prevented to do, but that’s the point—it’s a learned the interference. J behavior and atrophies if idled. —Vic Syracuse

Photos: Tom Wilson KITPLANES March 2018 79 KIT STUFF BY ROBRUCHA

80 KITPLANES March 2018 www.kitplanes.com & www.facebook.com/kitplanes The only direct aircraft insurer. Talk to us. (888) 241 7890 Avemco.com Avemco Insurance Company is a member of the Tokio Marine HCC group of companies. ADS0159 (12/16)