Backcountry Bearhawk: a Custom Cruiser

BACKCOUNTRY BEARHAWK: A CUSTOM CRUISER KITPLANES July 2020 Kits forKits Under $25K • Custom for Bearhawk • ADS-B • Little Guys S-21 • Building a RANS Torque Wrench GI 275 • • Garmin Basics • COVIDityWing Blues • Nutserts Stands 2020 July KITPLANES

STOP IT! JULY 2020 Tips for Better Brakes

BELVOIR PUBLICATIONS BELVOIR In the Shop: ADS-B FOR LITTLE GUYS • DIY Wing Stands Can You Fly Without It? • Torque Wrench Basics • Mastering Nutserts RANS S-21 OUTBOUND

Let the Building Begin! www.kitplanes.com

CONTENTSJuly 2020 | Volume 37, Number 7 Builder Spotlight 6 17 KITS FOR UNDER $25K: Building economically can be done, but you’re going to be part of the cost savings. By Marc Cook. 20 RETIREMENT PROJECT: A backcountry Bearhawk built for comfort, cross-country cruising and cargo capacity. By Scott M. Spangler. 28 MIKE AND LAURA STARKEY’S RANS S-21: Part 1— foundations of the build. By Laura Starkey. 34 ADS-B AND THE LITTLE GUY: ADS-B installation may be avoidable for many small homebuilts. By Ron Wanttaja. 38 GARMIN GI 275 EFIS: This full-featured, full-priced certified 20 EFIS is impressive but might not be ideal for homebuilts. By Marc Cook. 44 AIRCRAFT BRAKES: Some experiences and improvements. By Reinhard Metz. Shop Talk 49 NUTSERT NOTES: Mastering these little beasts. By Paul Dye. 52 MOUNTING ON A CURVE: Put your GPS antenna where it belongs. By Paul Dye. 54 PLANE AND SIMPLE: Support your wings. By Jon Croke. 58 MAINTENANCE MATTERS: Torque wrench basics. By Dave Prizio. 64 HOME SHOP MACHINIST: Lightweight stepladder. By Bob Hadley. 72 AERO ’LECTRICS: VHF com—the good, the bad, the ugly. By Jim Weir. 79 UNAIRWORTHY: Jam nut triple threat. By Vic Syracuse. Designer’s Notebook 75 WIND TUNNEL: Design process—span and aspect ratio. By Barnaby Wainfan. Exploring 2 EDITOR’S LOG: What’s next for aviation in America? 6 By Marc Cook. 4 FREE FLIGHT: Funny money. By Paul Dye. 56 BUILDING TIME: Murphy’s law, Occam’s razor. By Kerry Fores. 62 OUT OF THE BLUE: COVIDity blues. By Myron Nelson. 78 REAR COCKPIT: Missing Red Bull. By Tom Wilson. Kit Bits 68 LIST OF ADVERTISERS 69 BUILDERS’ MARKETPLACE 80 ARCHIVE: Looking back at the January 1988 issue.

On the cover: six kits for under $25,000. (Clockwise from upper left) Hummel H5, Van’s RV-4, Fisher Dakota Hawk, Aeromarine Merlin, Zenith CH 650 and Airdrome 28 Aeroplanes Sopwith Camel. For subscription information, contact KITPLANES® at 800/622-1065 or visit www.kitplanes.com/cs. KITPLANES July 2020 1 EDITOR’S LOG What’s Next for Aviation in America? Never have I wanted a column of has emerged. While the Boeings of the and rejiggered the shift schedules and/ mine to become obsolete, inconsequen- world have had to shut down and fur- or working environment to maintain tial, a curious blip in time more than lough employees, the initial reaction of proper social distancing consistent this one. In the 30 days since I wrote last people closer to our orbit than Boeing with requirements in their home states. month’s column to now, early April, our or Airbus has been much more subdued Inconvenient, but they’re still opera- world has come to a virtual standstill. The and, even, just a little bit positive. tional and that’s a big deal. immediate effects of the coronavirus (or We benefit from being made up of Until at least mid April, companies COVID-19) have been to sequester indi- smaller, more agile companies. And such as Van’s, Zenith, Sonex and Kitfox viduals and families, shutter businesses because the margins in manufactur- were continuing to build kits and com- big and small and, tragically, cost lives ing aircraft kits is thin, few of our components, while also providing sales and around the world. By the time you read panies are in big cities—no one needs support via phone and internet. As this this, the wide-ranging shelter-in-place that kind of high rent. So you’re likely is written, Sun ’n Fun has been canceled restrictions might be starting to lift. Or to see our industry leaders in more for this year—“combined” with the 2021 they may not. We’re learning more every rural locations, which so far have been event is the official word. But the need to day but we still don’t know enough for spared the brunt of the outbreaks. That make a go/no-go decision on AirVenture any kind of lucid prediction. doesn’t mean they’ve been untouched. is still a month ahead of us—so, offi- As I watch more or less from the side- A few are working with minor changes cially, it’s still in “go” mode. My crystal lines—your dedicated crew members to their processes, mainly by limiting or ball, which years ago I nicked with some here at KITPLANES® are generally virtual- eliminating factory tours and customer 60-grit and then mistakenly cleaned with office types except for those who have, pickup of kits and components. Most MEK, is as fuzzy as ever, but I’d guess um, real jobs—something interesting have sent office staff to work at home the best case is we’ll have a delayed AirVenture, and worst case, none at all. I’m trying to remain hopeful—but I don’t see it happening in late July. Already our industry is adapting. Zenith chose to move its builder workshop to a virtual platform and the Sonex Builders Group staged a Zoom-based fly-in. I expect more kit companies and builders groups will do the same, their delayed events hemmed in by all the summer activities that we might get to do by September on one side, and the onset of winter on the other. I do know that the enforced downtime affords the opportunity to get over to the hangar or down to the basement to continue working on our projects, and I’ve heard from builders Is general aviation sinking into the ground as the result of COVID-19? I don’t think so—at least not permanently.

Marc Cook is KITPLANES’ Editor in Chief once again, after a hiatus playing with motorcycles and learning about e-commerce. A veteran special-interest journalist, Marc has built two airplanes, an Aero Designs Pulsar XP and a Glasair Aviation Sportsman, and now owns a 150-hp, almost-as- simple-as-it-gets GlaStar based in Oregon. Marc has 4500 hours spread over 200-plus types and Marc Cook three decades of flying.

2 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes A once-vital small airport goes almost silent when the pilot-training activities cease and most pilots respect the stay- at-home mandates even though social distancing isn’t hard to maintain out here. I finally found Aviation Safety Products in Blairsville, Georgia. They do everything with seat belts. You can buy complete harnesses, re-web belts or simply modify one half of a seat belt. I sent them the half belt I wanted modified (they reused my attach fitting) and specified the length I wanted. If I remember correctly, it took who are taking advantage of the situation made more noticeable with the off-center just over a week to get my part and it was to pound rivets or spread resin. shoulder belts. Nobody could supply me quite inexpensive. Success!” My apolo- Of course, the big question is how with the simple mod that I needed. They gies to Aviation Safety Products (www. we will fare at the other end of this pan- all wanted me to buy new belts. The belts aircraftseatbelts.com) for somehow miss- demic. There are many variables still in in my airplane are four-point harnesses so ing them in our story—and thanks to play but I find myself surprisingly opti- they would be quite expensive to replace. Tom for pointing this out. J mistic. I was in this chair during the eco- nomic crash of 2008 and it felt different. I EDITORIAL ADVERTISING sense a coming together of human spirit Editor in Chief Marc Cook Advertising Director Tom Bliss and a sort of resilience that I didn’t get [email protected] Belvoir Aviation Group [email protected] 602/625-6815 before. What I hear are things like, “We’ll Editor at Large Paul Dye Executive Editor Mark Schrimmer Advertising Representative Ivy Ericksen do that when“ rather than if. [email protected] I worry about our airports and FBOs, Art Direction Dan Maher 612/743-8512 however. At my home base, you could Contributing Editors LeRoy Cook, Jon Croke, BUSINESS OFFICE Kerry Fores, Robert Hadley, Belvoir Media Group, LLC sense a slackening of activity early in Dan Horton, Louise Hose, 535 Connecticut Avenue, Norwalk, CT 06854-1713 March and then a much bigger drop-off Amy Laboda, Dave Martin, when the local flight school suspended all Sid Mayeux, Myron Nelson, EDITORIAL OFFICE David Paule, Dave Prizio, Ken 535 Connecticut Avenue, Norwalk, CT 06854-1713 flight training. Many of the students were Scott, Dick Starks, Eric Stewart, [email protected] from out of state, here only for training. Vic Syracuse, Barnaby Wainfan, Jim Weir, Tom Wilson. SUBSCRIPTION DEPARTMENT Some will be able to hang on and wait it 800/622-1065 out, some will have to go home—and Web Editor Omar Filipovic www.kitplanes.com/cs I don’t know if they’ll be able to return Cartoonist Robrucha P.O. Box 8535, Big Sandy, TX 75755-8535 once the restrictions are lifted. On top of Editorial Director, Larry Anglisano REPRINTS FOR PUBLICATION Aviation Division the likely free-fall of pilot demand as the AND WEB POSTING AVAILABLE CIRCULATION Minimum Order: 500 airlines very slowly creak back toward Circulation Manager Laura McMann Contact Jennifer Jimolka, 203/857-3144 capacity later this year, it’s a difficult and sudden change in prospect for young, career-aspiring pilots. I feel for them. Change of Address? Missing Issue? Subscription Question? Belted Visit www.kitplanes.com/cs. or call 800/622-1065 from the U.S. and Canada Foreign 903/636-1112 or fax 203/857-3100 Tom Decker wrote in to comment on LeRoy Cook’s recent seat belt feature (“Belting Your Homebuilt,” May 2020 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. KITPLANES®). “Great article. [LeRoy] lists Unsolicited manuscripts: Are welcome on an exclusive basis, but none can be acknowledged or returned unless accompanied by a stamped, self- some of the suppliers for this product. I addressed envelope. No responsibility is assumed for loss or damage to unsolicited material. would like to mention one more. A cou- 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, ple of years ago, I went searching for a Exec. Vice Pres./Marketing Dir.; Ron Goldberg, CFO; Tom Canfield, Vice Pres., Circulation. company to modify the non-buckle por- Periodicals postage paid at Norwalk, CT, and at additional mailing offices. Copyright ©2020 Aviation Publishing Group, LLC. All rights reserved. Reproduction tion of the passenger seat belt in my Pul- 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. sar 582. This half of the seat belt was not funds for Foreign Air Mail. Single copy price $4.99 U.S., $5.99 Canadian. adjustable. Some of my passengers were POSTMASTER: Please send address changes and subscription inquiries to: KITPLANES®, P.O. Box 8535, Big Sandy, TX 75755-8535, or Canada Post: Return slightly challenged around the waist. The undeliverables to P.O. Box 2601, 6915 Dixie Rd, Mississauga, ON L4T 0A9 or call 800/622-1065. seat belt would not sit in ‘their’ center, KITPLANES® is a registered trademark of Aviation Publishing Group, LLC.

Photos: Marc Cook KITPLANES July 2020 3 FREE FLIGHT Funny Money When I was a kid, way back in the to spend the extra nickel—that was a big them in the wildly expensive aviation 1960s, one of the toughest decisions I deal! It became no easier when we’d get marketplace of aircraft tools. had to make was whether to buy a five- to the store and right next to the candy However, just because early learn- cent candy bar or spring for the larger aisle, I’d find the little balsa airplanes ing is persistent that doesn’t always 10-center when I had been given my packaged in cellophane. make it “right.” Sometimes we have weekly allowance of half a buck. My They had the pure glider model for to learn new perspectives and ways of friends and I would walk the direct path a quarter, and the kind with the rub- looking at things. Now, since we’re all through the old farm fields that were ber band and landing gear right next to homebuilders here, we should be able slowly being turned into suburban those for probably 50 cents. Now here to take as given that tools are important. homes to the neighborhood drug store was a dilemma—buy the candy bar or There’s no questioning that the guy with and figure out how we were going to save for a new airplane? I’d have to men- the most tools wins! But, still, that early spend the summer day. Yeah, it was a tally catalog the status of the airplanes learning sits on our shoulder, reminding little Rockwellian, a much more innocent I already had to figure if I had enough us that we shouldn’t be extravagant. time. But that decision on whether or not parts between those with broken wings Yet this can often lead to a “penny wise, and those with stripped off landing gear pound foolish” attitude that can gener- to make a flying example—and weigh ate real problems. that against the desire for that Butterfin- Take, for example, a dilemma I had a ger. It was a tough choice. few years ago while upgrading to elec- Sometimes I’d go through the pack- tronic ignition. This required removing ages carefully to see if any of them had the magnetos entirely and replacing a double set of wings—the packaging them with electronic mags, neither of process sometime let two sets of the which needed an impulse coupler. This thin balsa sheets stick together, and you meant that the impulse coupler adapter could get spare parts without having could come off the left side mag hole to pay for them! Maybe one in a hun- and, because of this, the studs were now dred was like this—but I’d check, and if I almost an inch too long. So the studs had found a bonus pack, that settled it: The to be replaced. Getting those studs out airplane was mine! with the engine on the airplane was not an easy task—after all, they’d been on Money Matters there for 1600 hours of heat and cold. This philosophy comes from grow- Even double-nutting them was not ing up with depression-era parents working. You could see the dang things of course—we were always thinking trying to twist and, frankly, there were about how to best spend money, even engine-mount tubes in the way of the though we were a comfortable middle- wrenches so that you just couldn’t get a class family. It was ingrained, and early good angle on them. A dedicated stud-pulling tool might sit in learning stays with you. So, even today, What I needed was a really good, the back of the box for years. But when you I find myself thinking about how to best high-quality stud puller. Snap-On made need it, you really need it. spend dollars, even when I am spending one but it cost over a hundred bucks!

Paul Dye, KITPLANES® Editor at Large, 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 and SubSonex jet 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 Paul Dye motorglider. 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.

4 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes An expensive but useful torque wrench in a shiny-new case. I had to buy this for one bolt for one project, but now I can be the airport local with the go-to, high-capacity torque wrench.

Wow—that’s a lot for a tool that you’re nut that has to be torqued to 225 foot- only going to use once in a while and pounds. Yeah, that’s a good-sized guy it was a struggle to come to grips with hanging from a good-sized wrench! My the need. Then I got to thinking what stash of torque wrenches would get me to it would cost if I messed up the acces- 80 foot-pounds. A neighbor had one that sory case by breaking off a stud. Not would go to 150. I briefly thought about only would it cost money in machining, the fact that a German motor could prob- it would take a huge amount of time ably be built using the “German torque” to pull the engine, find the necessary method known as “gutentight,” then engine stand to do the work, etc., etc. A thought about that flywheel coming loose Print & hundred bucks for a tool didn’t seem so in flight. That would not be a pleasant day, bad when stacked up against hundreds even in a motorglider! I figured that since of dollars of potential additional costs if no one else in the airpark had a torque Digital I screwed the thing up. wrench that went up that high, why not The clincher came when I found that a be the go-to guy in the future? It cost me Either Format– friend had the tool in a city a couple of $110 for the wrench but it came in a nice Great Savings! hundred miles away—I hopped in an air- storage box where it will stay until called plane, flew up there, bought him lunch, upon for some future task. borrowed the tool and did the job right. Penny wise and pound foolish. A lot of It took just a minute or two to get the us were brought up that way. But when stud off and I returned the tool when the we get into aviation, we learn that the airplane was flying again a few days later. risks are greater than we find in automo- Yeah, I probably spent as much in avgas tive work or homeowner projects. Some- as I would have if I’d bought the tool out- times you just have to spend the money right—and, eventually, I did buy the right to do the job right—if you don’t have tool so that I could be the one loaning it the money, you have to wait until you out next time. But the lesson of using the do. After all, airplanes fly due to proper right tool for the job was learned. funding—and while in today’s world you might be choosing between a 50-cent Still Valid Today cup of coffee from the office machine Fast forward to a recent job we’ve got versus a $5 Starbucks, its not really that going, building up an AeroVee engine different from those five-cent candy for our motorglider project. The flywheel bars. Keep your eye on the prize—a safe Subscribe now at attaches to the back of the crankshaft airplane—and save those pennies for www.kitplanes.com/ on this VW-based motor with a gland what really matters. J subscribe

Photos: Paul DyeBertorelli & Courtesy of Paul Dye KITPLANES July 2020 5 17 KITS FOR UNDER $25K

6 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Building economically can be done, but you’re going to be part of the cost savings. BY MARC COOK

Aircraft can be expensive, every- arrived as a completed idea: What kit and build time. Instead, at this price level one knows that. It’s part of the reason can you buy for $25,000 or less? Now, for a new kitbuilt, we’re talking basic, fun we elect to build our own—to do so for before you begin thinking that this airplanes meant for good-weather flying. less than it costs to buy a new or used is, already, a wholly too large sum for Sometimes not very far from home. But, series-built design, to save us money on the start of your project, consider that if you think about it, that’s where many maintenance and to make the outcome the average vehicle (statistically, a Ford of us started, making a light, simple uniquely ours. In a very broad sense, new pickup truck) costs around $37,000. airplane a welcome bit of homecoming aircraft kits have barely kept up with Sure, that F-150 can take you to Home for experienced pilots. The key here is inflation and the pre-COVID-19 appre- Depot, but can it take you flying? Not to keep the endpoint of the project in ciation of certified aircraft. Improve- more than once, anyway. mind—what does the design want to be? ments in manufacturing processes have A few things before you begin to Avoiding mission creep is the only way to partially offset the increase in the cost of flip to our survey. First, in order to get stay within a modest budget. the raw materials and, it should be said, under the limit, some designs are in There are other benefits to maintain- many of the more prosperous kit compa- their “base” configuration, meaning no ing simplicity. A smaller engine needs nies are loathe to mess with a good thing. quickbuild components, no factory- less fuel, and therefore needs less fuel We have, as a result, a long list of familiar sourced common parts (like wheels capacity; that gives you payload and per- designs that have benefitted from years and brakes) and, for the most part, no formance. A carburetor will be cheaper of development, builder feedback and engine, prop, electrical, avionics, inte- to own in the long run than fuel injec- other measures to make them not just rior or paint. Traditional thinking has tion—simply from the parts count, to better airplanes but also easier to build the completed price of an Experimental/ say nothing of the possibility of find- more accurately than ever before. Amateur-Built aircraft at roughly three ing what you need in the used-equip- It’s tempting for us to follow what’s times the base kit cost, putting our ment bin—and a fixed-pitch prop will new and get sucked toward the high end bogey at $75,000 complete at the high exchange more limited performance of our sport, but with markets reeling end of this range. It doesn’t have to be. for—again—low weight and cost. Every and everyone looking to do more with Next, consider your aircraft needs. For one of these decisions in the simple- fewer dollars, we felt it would be smart some builders, the desire to move toward versus-complex thought process brings to reassess the less costly end of the the most sophisticated, capable end of follow-on effects, some that are merely spectrum. So the thought experiment the spectrum piles on cost, complexity additive, some exponential.

Aeromarine-LSA’s affordable Merlin.

Photos: Richard VanderMeulen and Courtesy of the Manufacturers KITPLANES July 2020 7 A lighter, simpler airplane also means after all—but what it does suggest is C-85 up front, though several variants of easier shopping in the avionics aisle. that extreme caution is warranted before Continental’s popular flat-four up to 120 Gyro system? Forget it. Multiple nav/ starting a design supported by them. The hp will go, and provides a breezy 100-mph coms? Um, no. ADS-B? Depends on unfortunate truth is that creating kits for cruise. Top speed is just 10 mph greater, where you’re based and where you want homebuilt aircraft rarely is lucrative. You but it probably feels like a lot more with to fly. The trick to building a low-cost may need a side business to support the the wind rushing by your ears. With a airplane is to actively scrutinize every fun side or, like Van’s, Zenith and a few gross weight of just 950 pounds, the Baby line item. And then spend where safety others, do it at a scale that is profitable. Ace is LSA legal. Three versions, the B, C depends on it: proper hardware, a solid We’re going to redouble our efforts to and D are differentiated by landing-gear (even if used) engine, proper restraints verify business condition as we set about design and the shape of the tail. and thoughtful assembly. updating our kit guide for 2021. (Prices Construction is a combination of Some of the company names you’re listed are current as of April 2020.) CNC-cut steel-tube fuselage, some wood familiar with may not be here—even And last, you may notice some com- in the wings and otherwise conventional some that show up in our aircraft direc- panies that we know are vital that are fabric covering. While the Baby Ace tory as currently in production. For this simply not represented. Kitfox has dis- looks right as a taildragger, it can actually story, we once again reached out to check continued the Model IV, which was its be built with a nosewheel. The options on the health of the suppliers and found only offering with a kit base at or below list is extensive, including your choice some of them to be unresponsive. That $25K. Same for RANS, which recently of fully welded fuselage shell, a pile of doesn’t mean that they’re gone—we were trimmed its model offerings, putting all CNC-cut tubes or tack-welded tubes in the midst of the coronavirus crisis, of its models above the threshold. What that you finish; the same choices exist does this really tell us? That constant for the tail feathers. You can also choose

Ace Aircraft, Inc. improvement in basic kits—including from a single 17-gallon fuselage tank or more and doing more of the work at the wing tanks totaling 23 gallons. Baby Ace factory, which the market has definitely Kit cost ...... $18,950 responded to—has raised the price Aero Adventure Aventura HP Total build cost ...... $35–75k floor. With more builders demanding In the world of Experimental/Amateur- Seats ...... 1 quickbuild options and willing to pay Built aircraft, there has always been a bit Gross weight ...... 950 lbs for them, you can hardly blame them. of crossover to ultralights. After all, our Max speed ...... 110 mph world didn’t start with the Lancair IV or Cruise speed ...... 100 mph Ace Aircraft Baby Ace the RV-10. And while the very light end Stall speed ...... 35 mph The Baby Ace, a long-distance cousin of of the market isn’t as robust as it once Available in plans ...... Yes the original Corben designs of the late was, there are still some great options. LSA ...... Yes 1920s, is in many ways the quintessential The Aventura HP is among them. With Contact ...... www.aceaircraft.com early homebuilt. This parasol-wing, open- the airframe kit starting at $22,000, the cockpit “flivver” mounts a Continental HP offers a choice of engines well suited

Byron Poppenhagen’s Baby Ace with an O-200.

8 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Aero Adventure Aviation Aventura HP Kit cost ...... $17,995 Total build cost ...... $24–32k Seats ...... 1 Gross weight ...... 750 lbs Max speed ...... 90 mph Cruise speed ...... 75 mph While the Merlin is definitely light and simple, the demo airplane does have glass. Stall speed ...... 32 mph grass strip. The HP has a host of options not take much power to get the Merlin Available in plans ...... No available, including a carbon-fiber hull, a off the ground quickly. LSA ...... Yes $2800 upcharge that still gets the whole Our own Paul Dye flew the airplane Contact ...... www.sea-plane.com airframe kit in under $25K. in 2016 and concluded that the “Mer- lin is what we think a Light Sport Air- to this modest point of entry: the Italian Aeromarine-LSA Merlin craft should be—easy to maintain and MZ 201 twin-cylinder, two-stroke of 45 If you truly believe light is right, simpler hp; the MZ 202 of 60 hp; or the Rotax is better and you have no need to take Aeromarine-LSA 582 of 64 hp. There are other Aventura passengers along, the Merlin should models intended for the Rotax 912 or be on your radar. The Czech design Merlin the AeroMomentum engine, but they’re is largely conventional aluminum, with Kit cost ...... $18,500 more expensive kits. a cantilevered wing, single-seat cockpit Total build cost ...... $30–50k This single-place, Dacron-covered and the option of either a Rotax 582 Seats ...... 1 amphib has a max-gross weight of just or the new Aeromarine 800cc V-twin Gross weight ...... 715 lbs 750 pounds, which makes the most of the engine with 60 hp. Performance is Max speed ...... 150 mph 60-ish horsepower on board. A 90-mph listed as 90–120 in cruise, variable by Cruise speed ...... 120 mph cruise speed will be sufficient to drop installed engine power. Max-gross Stall speed ...... 38 mph into local lakes or check out the nearby weight is just 715 pounds, so it should Available in plans ...... Yes LSA ...... Yes Contact ...... aeromarine-lsa.com

KITPLANES July 2020 9

CGS Hawk Aviation fun to fly. With good handling quali- criteria. They follow the classic simpler- ties, it challenges the pilot to perfect is-better approach but the designs, while Hawk Plus their short landing technique, but in a appearing quite anachronistic, have Kit cost ...... $14,826 friendly way that is low risk. The rugged more than a bit of ultralight in them. For Total build cost ...... $22–28k construction should make it tolerant to example, the major structure is made up Seats ...... 1 the occasional mistake, and the cockpit of aluminum tube riveted together via Gross weight ...... 1000 lbs layout is first-rate.” gussets. It’s covered with conventional, lightweight Dacron. Max speed ...... 100 mph Airdrome Aeroplanes Three years ago, Sam Buchanan Cruise speed ...... 85 mph Sopwith Camel chronicled the build of an Airdrome Stall speed ...... 40 mph We chose the Sopwith Camel for this Fokker, and his experience suggests these Available in plans ...... No exercise but most of Airdrome’s repli- aircraft are really best aimed at those LSA ...... Yes cas could meet our under-$25K kit cost with previous building experience and Contact ...... www.cgsaviation.com the willingness to improvise as you go. (Kind of like the roots of homebuilding, price around $15,000, it may be possible if you think about it.) There’s a strong to build a complete Hawk Plus for near support group, but these are definitely our kit-only cutoff point. not paint-by-numbers aircraft. To do so, you’ll want to stick to the Performance is modest. We’re talk- lower end of the Plus’s power spectrum, ing airplanes whose cues come from the which runs from the 40-hp Rotax 447 very earliest days of aviation. With the all the way to the 65-hp HKS 700E big Rotec radial, the full-sized Camel four-stroke at the top; the Rotax 503 is good for 93 mph. Another option is (50 hp) and Rotax 582 (65 hp) are also a large VW-based engine, which does options. At 350 pounds empty against help keep the overall costs down. You an 800-pound maximum-gross weight, Airdrome Aeroplanes, Inc. can build any of the Airdrome designs the Hawk Plus has good payload. Cruise for relatively little money and you’re speed is listed as between 60 and 80 Sopwith Camel almost certain to have the only one of its mph, so whatever it is you’re carrying (Full Scale) kind on your airport. in the back won’t need to get there too Kit cost ...... $13,495 quickly. But, then again, when your Total build cost ...... $33–40k CGS Hawk Aviation Hawk Plus only goal is simple aviating, speed is not Seats ...... 1 It may seem incongruous for ultralight always the prime concern. Gross weight ...... 1243 lbs designs to need more baggage capac- Max speed ...... 103 mph ity, but it’s less unusual than you might Fisher Flying Products Cruise speed ...... 85 mph think. We as a society like to take our Dakota Hawk Stall speed ...... 40 mph stuff with us. Like camping gear. A big As with Airdrome Aeroplanes, Fisher Available in plans ...... No cooler of Mountain Dew. It’s your call. could well take over most of the spots LSA ...... Yes With the Hawk Plus, what you get is on this list—at least 14 of the 17! The Contact . . .www.airdromeaeroplanes.com basically a single-seat version of the two-place Dakota Hawk is one of those twin-seat Hawk Arrow. With a base kit friendly, high-utility aircraft that’s quite

Airdrome Aeroplanes Fokker DR-1 exemplifies the company’s commitment to war-replica designs. (Photo: Dick Starks)

10 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes

Fisher Flying Products Dakota Hawk Kit cost ...... $14,900 Total build cost ...... $25–35k the Rotax 912 and 912S, on up to the four-cylinder engines, which provide Seats ...... 2 Jabiru 3300. On the 80-hp 912, the excellent performance: cruise of 100– Gross weight ...... 1150 lbs Dakota Hawk’s performance is listed 130 mph, 800–1200 fpm climb, all with Max speed ...... 100 mph as 90–100 mph cruise and a climb rate a 42 mph stall speed. Empty weight is Cruise speed ...... 100 mph of 800 to 1000 fpm. Stall speed is listed quoted as 460 pounds, against a max- Stall speed ...... 35 mph as 35 mph, no surprise given the wing gross of 850 pounds. Available in plans ...... Yes loading. And speaking of wings, the LSA ...... Yes Dakota Hawk has the option of folding Hummel Aviation Contact ...... www.fisherflying.com feathers. The airplane is primarily wood but comes with Dacron fabric and Stew- H5 human sized; in fact, it’s the largest of art adhesives in base form. Quickbuild Kit cost ...... $17,200 the Fisher designs. You get a wing of components are also an option. Total build cost ...... $17.2–32k 128 square feet on an airplane with a Seats ...... 1 gross weight of just 1150 pounds, which Hummel Aviation H5 Gross weight ...... 850 lbs affords strong climb performance and Morry Hummel’s designs have always Max speed ...... 135 mph short takeoff and landing rolls. What been about elegant minimalism, and Cruise speed ...... 120 mph you want in a utility design. that doesn’t stop with the thoroughly Stall speed ...... 41 mph The Dakota Hawk can use a number updated H5. The metal H5 can be built Available in plans ...... Yes of popular engines, from the stalwart as a tri-gear or taildragger, with up to 85 LSA ...... Yes Continental C-90/O-200 family to hp. Most are built with converted VW Contact ...... www.flyhummel.com

KITPLANES July 2020 11 start with a fairly complete base kit and go austere from there. The Highlander has the middle- sized wing area of the four Just models and can be built as a taildragger or tri- gear. Cruise with a Rotax 912S on the nose is 105 mph. Like its stablemates, the Highlander is LSA compliant with a 1320-pound max gross; its empty weight is a claimed 615 pounds for a Technology, Capability, Affordability 705-pound max payload. Normal fuel is 18 gallons but 26 is an option. The turbocharged Rotax 914 is an option, but it’s an expensive engine and therefore FLYDYNON isn’t likely to be chosen by anyone con- cerned with a low kit price. We’ve been impressed with the Highlander and Just Aircraft overall; the side-by-side High- lander has good utility, impressively short takeoff and landing distances and This Hummel H5 keeps it simple inside and out. (Photo: Mariano Rosales) solid handling. Like many small manufacturers, and responsive, yet not twitchy. I was Hummel doesn’t officially create full surprised, in fact, at the harmonious Kolb Aircraft Company kits. As Paul Dye reported when he nature of the controls in an airplane Twinstar Mark III NEW LOWER NEW LOWER NOW STC visited, “Customers can simply buy whose design is still fairly young.” Kolb’s Twinstar is something of a vet- PRICE PRICE APPROVED a set of plans and get started, or they eran in this field, with a profile that can choose to purchase blanks (precut Just Aircraft Highlander might as well be in the dictionary sheet metal), fully formed parts, or par- The Just Highlander squeaks under our under “lightweight fun.” The pusher tially completed assemblies. The price $25K kit limit by a mere $100, but it design has side-by-side seating and the list shows virtually every part of the offers a significant amount of standard ability to place a wide range of engines airplane, so builders can buy what they equipment, including tires and brakes, up and behind the cabin. From the don’t want to fabricate, and start from full elevator trim, fabric and adhesive, affordable Rotax 503 two-stroke, scratch on other components. Hum- seat harnesses and cushions. Many builders can decide to spend more on mel can also supply full-sized Mylar other designs at or near this price point the 64-hp 582 or significantly more on templates, allowing those who want don’t include any interior at all. Of the four-cylinder, four-stroke Rotax Skyview se skyview classic skyview hdx to source their own aluminum to have course, Just offers a long list of options 912S. The Jabiru 2200 four-cylinder is A simplified experience, now even more The original next-generation EFIS system, The premier SkyView experience, now also accurate patterns.” Some pre-punched to add to your bottom line, but you can also an option. affordable for 2020 trusted in thousands of aircraft STC approved for type certificated aircraft components help reduce build time and increase accuracy. Dye praised the H5’s handling, too. “Control in all three axes was excellent—quick

Just Aircraft Highlander Kit cost ...... $24,900 Total build cost ...... $58–85k Seats ...... 2 Gross weight ...... 1320 lbs Max speed ...... 132 mph Cruise speed ...... 105 mph Stall speed ...... 39 mph Available in plans ...... No LSA ...... Yes Contact ...... www.justaircraft.com DYNON.AERO 12 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Technology, Capability, Affordability FLYDYNON

NEW LOWER NEW LOWER NOW STC PRICE PRICE APPROVED

Skyview se skyview classic skyview hdx A simplified experience, now even more The original next-generation EFIS system, The premier SkyView experience, now also affordable for 2020 trusted in thousands of aircraft STC approved for type certificated aircraft

DYNON.AERO

Kolb Aircraft Company Twinstar Mark III Xtra Kit cost ...... $17,050 Total build cost ...... $32–45k Seats ...... 2 Gross weight ...... 1100 lbs Max speed ...... 100 mph Cruise speed ...... 90 mph Stall speed ...... 27 mph Available in plans ...... No LSA ...... Yes Contact ...... www.kolbaircraft.com

Considering the Twinstar weighs alternative. Notable for its roomy cabin, spring-gear style and change from flap- just 1150 pounds at max gross, the 160 the Rebel combines low empty weight erons to split flaps/ailerons. Go wild, eh? square feet of wing is more than gen- and a high max-gross (1600 pounds for erous, making for a low stall speed (a the bigger engines, 1450 with the Rotax nV Aerospace KR-2S claimed 38 mph) and 1100 fpm climb 912) for good utility. The Rebel airframe Perhaps one of the less-appreciated rate with the 912S and two aboard. is mostly pre-punched aluminum. designs of the 1970s, Ken Rand’s KR Cruise speeds run from less than 70 Speaking of engines, the range is from was known for its speed and efficiency. mph with the 503 up to 80 with the the 80-hp Rotax 912 up to the Lycoming Well, it’s still with us under the nV 912. Truth is, that much wing is great O-320 of 150-hp, with the O-235 the Aerospace company, which continues to for lift but you can’t really outrun recommended middle option. Argu- induced drag. ably, the Lycomings can be the better Murphy Aircraft Mfg. The base price of $23,529 does not value if you find good candidates on the include dual controls, brakes, or a fabric used market. Of course, if you’re think- Rebel covering kit. It does, however, include ing of going on floats later on, the O-320 Kit cost ...... $24,650 a fully welded chrome-moly steel-tube is your choice. While cruise speed goes Total build cost ...... $30–60k cage as the primary structure. Both the up a mere 5 mph (from 115 to 120 mph) Seats ...... 2 wings and tail fold for storage. between the O-235 and the O-320, Gross weight ...... 1600 lbs climb gains a lot. Max speed ...... 140 mph Murphy Aircraft Mfg. Rebel Like most mature kits, there are many Cruise speed ...... 120 mph While the massive Moose gets most of options. You can add to the standard Stall speed ...... 40 mph the ink for Murphy, the compact, two- fuel capacity of 44 gallons (up to 58), Available in plans ...... No seat Rebel remains a viable, low-cost change from the Cub-style gear to a LSA ...... No Contact ...... www.murphyair.com

14 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes nV Aerospace KR-2S Kit cost ...... $17,500 Take the ﬁrst step Total build cost ...... $21–28k Seats ...... 2 toward building Gross weight ...... 1100 lbs your own aircraft with Max speed ...... 200 mph Cruise speed ...... 170 mph ® Stall speed ...... 52 mph Available in plans ...... Yes EAA SportAir LSA ...... No Contact ...... www.nvaero.com Workshops make kits for the KR-2 and KR-2S. The Visit EAA.org/SportAir S, for stretched, is our choice here for the extra room. The additional 16 inches in for more information. length help with cabin comfort with more head- and legroom than the KR-2. EAA SportAir Workshops are sponsored by Originally an all-wood design, the KR-2S has a combination of wood and fiberglass—those parts are premolded— and those changes reportedly improve build time to just 800 hours. Trike or taildragger configurations are available. Performance is excellent for the power, typically provided by a converted 2180cc VW, the Corvair six-cylinder or the Continental O-200. The VW and SHEET METAL Continentals are in the 80- to 100-hp range and bring the KR-2S up to a cruise of 150–180 mph. The KR’s speed comes from its compact dimensions, including an 82-square-foot wing. Sonex Aircraft Sonex-B Sonex has made the case of being one of the leaders in affordable aircraft and that’s not an idle boast. Three of the five current Sonex kits, the Sonex-B, the Waiex-B and the Onex, all have base kit prices below $25,000. What’s more, it says something about the completeness of the kits that upgrading to quickbuild status adds a comparatively low $7600. If you follow Sonex’s worksheet, a completed Sonex-B or Waiex-B could be in your grasp for less than $40,000.

KITPLANES July 2020 15

Sonex Aircraft, LLC Sonex-B Kit cost ...... $23,997 Total build cost ...... $38–55k Sonex’s Waiex-B (shown) and Sonex-B share many features, just not the tail! Seats ...... 2 Gross weight ...... 1100 lbs Max speed ...... 150 mph Cruise speed ...... 130 mph leader at $7600 for the 80-hp version. a taildragger or trike (with the tri-gear Stall speed ...... 40 mph For the Sonex-B, cruise speed at 8000 versions slightly more expensive). Available in plans ...... No feet is given as 150 mph with the Aero- LSA ...... Yes Vee, or 20 mph greater with the 120-hp Sport Performance Aviation LLC Contact ...... www.sonexaircraft.com Jabiru 3300. Empty weight will vary Panther with equipment, of course, but the If you’re getting the sense that low-cost How Sonex does this is really through Sonex-B should give you between 480 airplanes have fewer seats, you’re catch- simplicity of design. They’re all-metal and 530 pounds of useful load, depending on. The Sport Performance Aviation airplanes with blind pull rivets and ing on engine; the 120-hp engine allows Panther is just such a solo endeavor, but straightforward systems. On the Sonex- an 1150-pound max gross. it’s not meant to be dull. Designed with B, you can choose several engines, Worth mentioning, too, is that handling manners that bring to mind including the AeroVee 80- and 100- Sonex has developed a truly compre- gentleman aerobatics, the Panther com- hp Turbo variants, the Jabiru 3300, hensive accessory and options list for bines good looks, fine handling and ULPower’s UL260 or UL350 or the all its designs. You can even have the critical build elements meant to keep Rotax 912. The AeroVee is the value Sonex-B (or Waiex-B or Onex) as either the cost down but the fun up. Paul Dye flew the airplane way back in 2014 and said of the handling: “The

Sport Performance Aviation LLC Panther Kit cost ...... $15,995 Total build cost ...... $28–50k Seats ...... 1 Gross weight ...... 1115 lbs Max speed ...... 170 mph Cruise speed ...... 138 mph Stall speed ...... 51 mph Available in plans ...... No LSA ...... Yes Contact ...... www.flywithspa.com

16 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Thorp Central Thorp S-18 Kit cost ...... $20,500 Total build cost ...... $30-45k Seats ...... 2 Gross weight ...... 1600 lbs Max speed ...... 215 mph Cruise speed ...... 180 mph Stall speed ...... 63 mph Available in plans ...... Yes LSA ...... No Contact ...... www.thorpcentral.com airplane stayed where I put it in both pitch and roll, with no tendency towards divergence. Elevator trim was more than adequate and suitably quick to establish whatever speed condition I liked. The airplane liked to stay at whatever angle of bank I desired—little additional stick force was required to keep it in—or to keep it from steepening.” The base kit is $15,995 and that includes pre-drilled aluminum wing skins, a steel fuselage structure that’s been fully welded and powder coated, the canopy and landing gear legs. The Panther is built around the Corvair six- cylinder engine and that helps keep costs down as well; however, other engines in the 100–120 hp range can be used. Two Panther versions are available: one with 93 square feet of wing for LSA compli- ance and one with a smaller, 85-square- foot wing for better performance. Thorp Central S-18 Classic designs don’t have to fade away. John Thorp’s T-18 is nearly 60 years old, but it continues on with Thorp Central as the S-18. Two inches wider and 5 inches longer than the original, the S-18 is an all-metal design with a distinctive “cranked” wing that’s flat across the center and angles up at the outboard sections for dihedral effect. It’s also unusual in the homebuilt world for having an all- flying stabilator tail—something Thorp

KITPLANES July 2020 17

Van’s Aircraft, Inc. RV-4 Kit cost ...... $18,180 Total build cost ...... $37–73k had experience with during the develop- Van’s Aircraft RV-4 Seats ...... 2 ment of the Piper Cherokee. Wing area It may surprise you to learn that three Gross weight ...... 1500 lbs is just 86 square feet, giving good wing of Van’s basic kits slip under our Max speed ...... 204 mph loading for the 1600-pound max gross $25,000 limit. As you’d expect, the Cruise speed ...... 192 mph weight. A similarly sized Van’s RV-6 RV-3 and RV-4 do, but so does the most Stall speed ...... 51 mph weighs the same but has more wing. basic version of the RV-7 (not the -A Available in plans ...... No Performance is strong in this one. model, though). For that, you’ll have LSA ...... No Engines from the Lycoming O-290 up to forego the quickbuild options on Contact ...... www.vansaircraft.com to the O-360 can be accommodated, the 7. Van’s helps you with this decision and an S-18 with a 180-hp engine and on the RV-3 and -4, since there are no ever made, it’s an intrinsically simple constant-speed prop is said to go 180 quickbuild options. design that by its size and nature seems mph in cruise and climb at a strong 1500 We’ve chosen the two-seat RV-4 here to encourage builders to keep it that fpm. Currently, the full kit runs just over because, well, it’s a sentimental favor- way. Where the similarly tandem RV-8 $20,000 for the two-seat taildragger. ite. One of the purest flying airplanes tends to end up more complex—more powerful, faster, heavier and costlier— the RV-4 seems perfectly happy in its role as a fly-for-fun design. Perfectly contented with 150–160 hp, the RV-4 is amazingly efficient, doing better than 200 mph on fuel flows that mean 32 gallons of fuel is generous, not stingy. That the RV-4 is still with us more than 40 years since its introduction says a lot about the design and the desire of builders to have this lightweight marvel. Wag-Aero Sportsman 2+2 Getting your kit components under $25,000 for a one- or two-place airplane is a challenge enough, but getting Original RV-4 kit. something with four seats that starts

18 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes

Zenith Aircraft Co. CH 650 Kit cost ...... $18,500 Total build cost ...... $40–65k Seats ...... 2 in the budget basement (so to speak) is if you build it light you’ll be rewarded Gross weight ...... 1320 lbs fairly impressive. That’s the Wag-Aero with impressive carrying capacity. Stan- Max speed ...... NA Sportsman 2+2. It’s not a new design by dard fuel is 39 gallons, generous with an Cruise speed ...... 160 mph any means, but a reproduction of Piper’s O-320 up front. Handling is straight- Stall speed ...... 44 mph PA-14 Family Cruiser aircraft. That forward and very Piper-like. Wag-Aero Available in plans ...... Yes means a basic tube-and-fabric design, allows you to choose among various LSA ...... Yes taildragger configuration and some options, like a fully welded or merely Contact ...... www.zenithair.com form of four-cylinder Lycoming up tack-welded fuselage frame, so if you front; Wag-Aero says power from 125 to have the skills to complete that part of 200 hp will do. the project, you can put more of your pieces fit together only one way—and Performance reflects wing area and budget elsewhere. blind pull rivets, which are much easier utility, meaning cruise is in the 120–125 for neophyte builders to work with, mph range, with added horsepower add- Zenith Aircraft CH 650 albeit more expensive than conven- ing most to rate of climb and shortening Here’s another manufacturer capable tional driven rivets. One advantage for the takeoff roll. Maximum gross weight of producing several of its basic kits at the bottom line is that builders don’t is 2200 pounds with an empty weight or below our $25K threshold. Thanks need quite as extensive a tool set. around 1100. Here’s another one where to the simplicity of design across the We’re highlighting the CH 650 in board and simple-to-manufacture alu- part because it’s become a little over- The Wag-Aero Group minum structures, the Zenith kits lend shadowed by the high-wing CH 701 and themselves to low-cost builds. And this 750 designs. Zenith says the 650 will Sportsman 2+2 is despite the company’s extensive use of cruise at 155–160 mph true airspeed at Kit cost ...... $23,000 match-hole tooling—where the metal 8000 feet on around 100 hp. Like most Total build cost ...... $45–60k Zenith models, the 650 can use a wide Seats ...... 4 range of engines, with support for the Gross weight ...... 2200 lbs Jabiru 3300, Rotax 912S, ULPower, Max speed ...... 128 mph Continental O-200 and Lycoming Cruise speed ...... 124 mph O-235. Although a bit heavier, the Stall speed ...... 38 mph O-200 and O-235 options may be a tan- Available in plans ...... Yes talizing choice since these engines are LSA ...... No more widely available used than either Contact ...... www.wagaero.com the Jabiru or Rotax. J

KITPLANES July 2020 19 Retirement Project

20 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes A backcountry Bearhawk built for comfort, cross-country cruising and cargo capacity. BY SCOTT M. SPANGLER

Photos: Bill Anton and Scott M. Spangler KITPLANES July 2020 21 A series of transitions defines every pilot’s life. For Bill Anton of Satanta, Kansas, retiring after 35 years as an ag banker coincided with maturing flying desires, “from cross-country and aerobatics to fun flying out in the boon- docks.” Now 72, “I’m thinking of how many more years of good flying I might have left,” he said. After more than 800 hours in the Van’s Aircraft RV-8 he finished building in 2006, “I was ready for something different.” A Bearhawk is certainly different. He chose it by following the same path Bill Anton and his Bearhawk, Freedom II. that led him to the RV-8 in 1998, when he decided it was time to build his own so those criteria remain. Measuring adding that he was a Cessna 172 partner airplane after flying a Piper Arrow for 2150x100 feet, Runway 1/19 forms for about two months. Relating a mid- 17 years. “I sat down and wrote a set of one side of their 15-acre property. Steps summer cross-country with his wife, “It criteria for what I wanted. I live out in from the hangar is the house they built beat us up and took a long time to get the country, have a grass strip and han- between 1979 and 1982 on the remains there, and I didn’t want to do that.” The gar, so I needed something that would of the family’s southwest Kansas home- Bearhawk cruises at 150 mph, “so you handle grass. And I wanted something stead. The Flying UV, so called because can go someplace in it.” that would go cross-country” with at one arm of the U flies over the V, is the Speaking from 12 years of RV experi- least one passenger, his wife, Nancy. family brand, the initials of the home- ence, “You have to be real careful what His list compiled, Anton sat down stead’s founder, Ulysses Victor Anton. you pack,” Anton said, adding that with the directory of available amateur- The RV-8’s usual passenger is also 72, when they camped at Oshkosh, it was built designs “and started crossing out “and it is getting to be a struggle to get Spartan. “With the Bearhawk’s big those that didn’t meet my criteria,” he in and out of the back seat.” Anton said. ole back doors, you just throw stuff in said. That included a requirement for “I’m not so sure the Bearhawk is any and take off.” Taking a friend to EAA how many were airborne. “A lot of them easier with those 31-inch tires, but once AirVenture 2019, he said all their camp- had only four of five flying, and those I you’re in, it is more comfortable.” ing gear, two tents, sleeping bags, mat- kind of eliminated.” Looking at his final Comfort, cross-country cruising and tresses, and a huge Yeti cooler “hardly candidates, “Since I’m a fighter pilot cargo capacity rounded out Anton’s filled up the back.” wannabe, I picked the RV-8,” he said. criteria for a backcountry airplane that To use the space more efficiently The Antons haven’t moved from their can go cross-country. “Some of them are when carrying two passengers, Anton Anton Flying UV Airport (SN98), 100-mile-per-hour airplanes,” he said, built a single back seat that replaces the

Mobile on its Goodyear tires, the Bearhawk fuselage rolls into the sunshine.

22 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Anton’s RV-8 made room for the Bearhawk fuselage in its Flying UV Airport hangar (left). The single back seat sits behind the pilot, making it easier to fill the space around it (right). side-by-side bench. It made its first flight said he bought the raw materials days “It took about seven years to build the in October 2019, when Anton and his after he retired in January 2009. wings. Thinking that this is going to take sons, Marc and Erik, both pilots, flew to Following the homebuilder’s mantra me forever, that I’m going to be too old to Critter’s Lodge, a private aviation pre- to do something every day, Anton started fly it if I have to put that fuselage together, serve in East Texas, for its annual long building parts. “If you get hung up on I bought one from Bearhawk Aircraft.” weekend fly-in. “They had probably 20 building an airplane, you’ll never get Given its complexity and the building or 30 airplanes there” at the grass strip there.” Each part presented its own chal- skills it requires, he doesn’t recommend just off Highway 7 between Crocket and lenges and decisions. He started making the plans-built Bearhawk to first-time Centerville, Texas. wing parts after deciding how to cut out builders. With the factory-built fuselage, the ribs and their lightening holes, how to no welding is required. However, Anton Building Decisions bend them and how to smooth them out. chose to weld a multitude of mounting Anton had plenty of steel tubing to Working from full-scale plans, he cut brackets and tabs for his control cables. build the frame for that single back out the rib form from a piece of 3/4-inch While building, Anton regularly seat. “Because I was retired, I’d have oak. A router turned sheets of alumi- flew his RV-8. On their way to Tuc- a lot of time, and with the hangar num into rib blanks, and a Scotch-Brite son, where their son Erik was retiring right here I decided that I was going wheel deburred them. Then, one at a after 20 years as an F-16 pilot, “Just to scratch build the whole thing.” time, he clamped the blanks to the form past Lordsburg, New Mexico, the oil Explaining that the Bearhawk is built block and beat them into shape with a temp started going up and the oil pres- like a Maule, a fabric-covered steel-tube big rubber mallet. Finally, he straight- sure started going down.” Heading to fuselage with all-metal wings, Anton ened every rib with his flanging tool. their closest refuge, Wilcox, Arizona, “The engine cratered with a big bang,” he said calmly. “I set it down on a dirt road a farmer had just graded out in a big orchard 2 miles south of Interstate 10. I didn’t bend anything.” The failed RV engine was a rebuilt powerplant, as was the Bearhawk’s zero-timed 260-hp Lycoming IO-540. “It was a really good deal—I got it for $20,000,” but he reconsidered it after the off-airport adventure. “A friend had taken his engine to America’s Aircraft Engines in Collinsville, Oklahoma, so I hauled my engine down there. They put it on a test stand, it ran perfectly, and that gave me the confidence to put it on the Bearhawk.” A three-blade MT prop turns the Making the most of his space, Anton built a construction fixture that held both wings. Lycoming’s horsepower into thrust. “I

KITPLANES July 2020 23 Anton designed his instrument panel layout with full-size photos of its avionics (left). A former Air Force avionics and instrument tech, Anton wired and installed all of the Bearhawk’s electrical components (right). don’t know if it is any better than a two- military combination of the pitot tube at Kansas State University. “That was blade prop, but it looks cool,” he said. and static port” in a single unit. the middle of Vietnam, so I was [mili- And it has better ground clearance than But the military unit would not tary draft category] 1A the minute I a two-blade, always important when work with the Dynon system, which graduated.” Instead of waiting for the looking at backcountry operations. requires a pitot tube plumbed to pro- notice of Vietnam ground pounding, he Bush wheels also increase the prop vide the source data for angle of attack. enlisted. “I’ve liked airplanes all my life; clearance. He started with 26-inch That pitot tube extends from the right when I was 5 I’d run out the door any- Goodyear tires. “Practically speaking, wing. Instead of putting in a static port, time I heard an airplane to see what was they are really a better compromise for Anton installed the military unit and flying over…it was a miracle.” landing on pavement and dirt. They are used its static port. “It’s a nice conver- The Air Force experience planted a tougher tire and will last longer, but I sation starter,” he said, if people notice Anton’s safety consciousness and the really like the look of those 31-inch Alas- the bilateral probes. important contribution made by a sec- kan Bushwheels.” A 10-inch tundra tire “Being an old Air Force avionics and ond set of experienced eyes. For his avi- is the third point of contact. An early instrument guy who worked on F-4s, onics work, Anton turned to an avionics Bearhawk builder, Eric Newton, who I like that stuff and went all-in on the technician in Liberal, Kansas, 30 miles wrote the builder’s manual and is really panel.” Anton installed a Dynon HDX south of Satanta. involved with the online builder’s group, system that includes a touchscreen dis- Having never worked with fabric, developed it for the backcountry flyers. play, autopilot, communication radio, Anton sought an expert to help him Big backcountry tires are not the intercom, transponder, and ADS-B Out cover the Bearhawk with Oratex. The Bearhawk’s only distinguishing feature. and In. For redundancy, he installed a company’s “main guy lives in Anchor- It has two pitot probes. A military-issue Garmin GNS-430 GPS navigator and age,” Anton said, and talking to him heated pilot/static head, like those on G5 display set up for IFR. at Oshkosh, he recommended another a P-51 Mustang, extends from the left Growing up in Satanta, the self- Anchorage resident, “so I paid his wing. An eBay find, “I really like the described farm boy earned an ag degree way to Dodge City.” They covered

Anton mounted the IO-540 and MT prop and built the cowling with builder assistance at Crotts Aircraft Service in Dodge City, Kansas (left). Anton covered the fuselage with the help of an experienced Oratex whisperer from Anchorage (right).

24 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes

BEARHAWK 4-PLACE

Typical completed price ...... $90,000–$120,000 Typical build time (quickbuild kit) . 1000–1200 hours Bearhawk N47NL (mostly plans-built) ...... 3000–4000 hours Number flying (at press time) ...... 100+ Powerplant ...... Lycoming IO-540, 260 hp Propeller ...... MT 3-blade, constant-speed

AIRFRAME Wingspan ...... 33 ft Wing loading ...... 15 lb/sf A Dynon HDX system with touchscreen dominates the panel; it is backed up with an IFR Garmin GNS 430 and G5 display. Fuel capacity ...... 50 gal Maximum gross weight ...... 2700 lb the airplane in 10 days, with Anton had built several RVs. “I was still work- Empty weight ...... 1604 lb doing all of the rib stitching and tap- ing, so I took off every Friday for four Typical useful load ...... 1096 lb ing by himself. “It goes on real easy and months and went up there” for a long Full-fuel payload ...... 796 lb shrinks down real tight.” weekend of work. Seating capacity ...... 4 Anton painted the metal wings to He did the same for the Bearhawk, Cabin width ...... 42 in match the fabric, but there’s no paint- with two major differences. “Being Baggage capacity ...... 200 lb ing involved with Oratex, so he turned retired, I either flew the RV or drove to decorations. “If you look at Bear- there every day,” Anton said. He fin- PERFORMANCE hawks, a lot of them use a bear claw. I ished the RV in four months of long Cruise speed (31-inch Alaskan Bushwheels) . .140 mph liked the hawk idea,” and he found his weekends. “The Bearhawk was six Maximum rate of climb ...... 1500 fpm on the internet. “It’s a tattoo stencil.” months of working with the Crotts’s Stall speed (landing configuration) ...... 43 mph The airplane’s name,Freedom II, has crew every day.” It is a stock airplane, Stall speed (clean) ...... 46 mph several meanings. “My RV was Freedom except for the extra windows in the Takeoff distance ...... 200–400 ft and this is my second homebuilt, then doors. “I thought they looked good, and Landing distance ...... 400 ft there’s the freedom of flight, and then it is really amazing when you’re flying! Specifications provided by Bill Anton and reality that freedom is not free.” You can look straight down from the Bearhawk Aircraft. As he did with his RV-8, Anton left door.” He also installed a skylight turned to Crotts Aircraft Service in and modified the top of the fuselage to and another hundred hours or so in the Dodge City, Kansas, roughly 60 miles remove the “Bearhawk hump.” Aeronca Champ he once owned, Anton east northeast of Satanta. One of the made the maiden flight of Bearhawk full-service FBO’s maintenance offer- First Flight N47NL (for his wife, Nancy Lynn) on ings is Experimental aircraft builder’s Prepared by more than 800 hours in his November 2, 2018. “I kissed the ground, assistance, said Anton, adding that taildragging RV-8 (N46BV for the year got in that baby and away we went. It one of its maintenance technicians of his birth and his name, Billy Victor) was a little out of trim. The Bearhawk

On takeoff the Bearhawk doesn’t use much of the turf runway.

KITPLANES July 2020 25 With its big back doors, loading the Bearhawk is easy (left). The two front doors have glass almost top to bottom, and the top half is next to have its latch replaced with gas springs (right). is a very rudder intensive airplane com- pilot; he also owns a couple of gliders miles and, by the 2010 census, is home pared to the RV-8. When I took off, I and does the tow thing.” to 1139 people. Situated a mile north was puckered up because I was trying to Southwest Kansas has changed a lot, of town, the Satanta Municipal Airport keep it upright. It wasn’t like it was roll- he said. “Growing up here in the 1950s (1K9), activated in December 1944, is ing over on me, but it had a heavy wing and ’60s, we were mainly dry land home to 14 single-engine aircraft. and the rudder was out of trim.” wheat farmers. It has evolved into irri- That works out to 81 people per air- Adding trim tabs on all of the control gated corn and alfalfa and soybeans.” plane, not counting the airplanes that surfaces resolved the problem during his They are the green in the center-pivot don’t live at the airport. Although the Phase I test period. Studding the wing crop circles, each a half mile in diam- Bearhawk lives at home, Anton man- with vortex generators improved its low eter that cover the landscape in a tight ages the city-owned airport, a self-ser- speed performance. Still, he said, “You polka-dotted pattern. vice source of 100LL. “The manager is really have to fly it. No sleepy feet.” What has not changed is that “a lot not a paying job, and the flight instruc- Anton started flying as a high school of ole farm boys here in southwest Kan- tor who probably taught half the guys in senior and soloed at K State. “Then life sas build airplanes, which is kind of an southwest Kansas to fly got old enough got in the way. College, the Air Force, I amazing thing,” Anton said. “There are and gave it up. I decided we needed got married in 1969 and out of the Air a lot of grass runways in a 50-mile radius, somebody to make sure things were Force in 1973. I finally got my license in so I’ve hit every one of them three or okay, so I took it on around 1995.” 1975,” an instrument rating in 1996, and four times. I’ve been to a lot of their fly- With the Bearhawk flying, Anton a commercial pilot certificate in 1998. ins, so I know them pretty well.” sold his RV-8 to a friend’s son-in-law “In the early ’90s I got a glider rating. But this shouldn’t be surprising. Given after AirVenture 2019. A former Marine Maybe that’s my next project, now that the distances between them, airplanes are fighter pilot going to work for United I’m a retired builder. Maybe I’ll go find a good way to get around. Consider this: Airlines, “I’m feeling real comfortable me an affordable glider. I’ve got a buddy In the 1910s, the founders named Satanta selling to him; I know that he’s not going about 30 miles from here who’s a spray for a Kiowa chief. It covers 0.59 square to take it out and do something stupid.”

Anton camped at EAA AirVenture Oshkosh with a friend in 2019.

26 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Look closely and you’ll see an airplane with bilateral pitot tubes.

With more room in his hangar, he started on some Bearhawk modifications. “I wasn’t happy with my cylinder head temps, and at Oshkosh [Bearhawk Aircraft’s] Mark Goldberg gave me some numbers [Bearhawk designer] Bob Bar- rows talked about” that compared the areas of the cowl inlets and outlets. Anton enlarged the outlet on the bottom of the cowl and reworked its flange. “I’m not totally happy with it. I think maybe my baffling isn’t real tight in one place, so I’m still working on it” and doing a number of test flights. Anton flies a lot. In the 10 months since the Bearhawk’s first flight, “I’ve got 136 hours on it,” he said. “I’ve never done that. When I worked, I was lucky to get 30 or 40 hours a year.” Needless to say, retirement “has been fun!” J

Not happy with the cylinder head temps, Anton has been working on the cowling’s outlet.

KITPLANES July 2020 27 Mike and Laura Starkey’s RANS S-21

Please welcome the husband-and-wife building team Laura and Mike Starkey. I met them visiting our editor at large, Paul Dye, last year—they are neighbors of Paul and Louise’s at the Dayton Valley airport, a high-desert paradise about 20 miles southeast of Reno. I’ve admired the S-21 design from RANS, that’s true, Part 1: foundations of the build. but I was also eager to have a more traditional BY LAURA STARKEY build to follow Paul’s own amazing SubSonex Years ago while we were living in Cameron Park, California, my husband, Mike, series. Randy Schlitter and his team have done took an interest in a new design that was being spoken of. At the time, it was only a lot to make the S-21 easy to build, or so it a promise that it would someday come out. And when it did, it was the RANS seemed, and I wanted to know if that effort pays S-21 Outbound. Back then, I was working full-time and we had a beautiful flying off out here in the real world. I was also inter- machine that was fast and well suited our needs, a Van’s RV-10. Mike has been a pilot ested in the couples dynamic at work, where it since the early ’70s and been involved with five Experimental builds, but never fully was obvious that Laura and Mike approach the completed his own project from start to finish. To do so was a dream he always had. build a bit differently. Fortunately, Laura agreed I grew up in a family of three brothers and was always treated as one of the boys—I to take on the responsibility of documenting the could compete with them and hold my own whether it was target shooting, riding build for KITPLANES®, which you’ll see roll out a motorcycle or off-road jeeping. My dad was a WW-II naval aviator who had a pas- over the next few months. Enjoy! —Marc Cook sion for flying that he passed along to his children. When I was 11 years old, we took

28 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes The Starkeys’ RV-10 was a terrific traveling machine (left) shown at Roche Harbor, Washington, and during their first visit to Dayton Valley Airpark (right), before they knew they’d be living there. Yes, that’s editor at large Paul Dye’s RV-8 in the background. a family vacation in a Cessna 206 across in our new life. We had no idea where 172 so I could finally get my pilot cer- the country. This was when my love we were going to land financially after tificate. He agreed and the deed was for flying began, but that chapter soon building a house and hangar on this done…I could finally be a pilot! I passed closed due to two of the family members beautiful piece of dirt that fronted the my check ride in June of 2018. Oh, how getting airsick nearly every time we went runway. I know our kids thought we sweet to finally be a pilot! up, one of those being my mother. were both crazy for wanting to move It was not until I met Mike that my to Nevada but they approached it with Back to the RANS passion for flying was able to grow once good humor. Our “going away gift” During the past couple of years, Mike again. I took lessons in his 1948 Stin- from them was a framed Google Earth would intermittently mention the sta- son taking just over 30 hours of lessons, picture of our dirt lot with a banner say- tus of the RANS S-21, where it was in soloed three times but had to give it up ing “Welcome Home.” the design phase and how close Randy due to my demanding full-time job. I retired in March, and by November Schlitter, the owner of RANS, was in Thirteen years later, we found our- we moved into our home. It was about the runup to selling the S-21 kit to the selves building a house at an airpark that time that I became aware that our public. I would always say: no, no, no, in Nevada after my retirement. We neighbor from when we lived in Cam- not interested! I felt satisfied with the sold the RV and our house in Cam- eron Park was selling his Cessna 172. Cessna and so really did not see the need eron Park to have the capital to invest I just about begged Mike to buy the for us to build a plane.

The RV-10 poses at Monument Valley, Utah. Its sale formed the financial basis for the move to Dayton Valley.

Photos: Laura and Mike Starkey KITPLANES July 2020 29 This is what you call a romantic anniversary: visiting “our dirt” (left) and staking out the build site (right) that would become the Starkeys’ home, workshop and hangar. I guess timing is everything! It wasn’t We had been spoiled by the RV-10 all me, I bounced up against its inherent until after getting my pilot’s certificate those years. Its power let you basically limitations pretty quickly. It was time and we started going places together point and go. to consider other options if we were that I had an epiphany—big time. We Another frustration I had with the going to have the aviation experience were flying to a “local” restaurant for 172 was the panel—it was all gauges we both wanted in retirement. breakfast, and as we climbed out of the and no glass! The RV-10 had two glass valley we live in—our home elevation is panels with round gauges as backup. As Other Considerations 4400 feet msl—it became clear that we copilot for many cross-country miles, The idea of building a plane was a huge could only climb at 300 feet per minute. I got very used to—or I should say jump from where I thought we were Sure, the temperature outside was in the spoiled?—dialing in our destination, going to be in retirement. There were mid-70s so density altitude was a factor, punching in the waypoints for gas, then just so many things to consider…time but a bigger one is that the Cessna was we were on the go! I could look at the factor (we weren’t getting any younger), struggling with the load. We were still terrain or God’s eye view easily. I always money factor and even the build itself. within the 172’s weight-and-balance knew where we were, which made navi- Now that I was retired, I could partici- envelope, but the performance was gation a no brainer. The added plus of pate in the build. We could co-build a marginal enough that I realized that we having two glass panels was not only plane of our choice. Since I had never were not going to be doing any cross- redundancy but the ability to dial in been involved in any build, this was country voyages. I didn’t even want to what I wanted to see without disturb- rather daunting to think about. Mike think of crossing the Sierra Nevada ing Mike’s display. It was sweet! So was willing to take me on as a co- with this kind of soggy performance. while the Cessna was a good trainer for builder, understanding that I was more of an apprentice-level builder and there would be a lot of learning ahead of me in the process. I was definitely willing to learn and he was willing to teach. Another consideration was that we would need to co-exist in this project with our differences in personality. We each have our strengths and weak- nesses—how would this work out? By trade, he is a wildland firefighter who thinks like an engineer. He is a very conceptual learner, being able to look at diagrams and just know how the pieces fit together, and then from that point just tinker around and make things work. I, on the other hand, am a nurse-turned-accountant who is analytical, very detail- and process- oriented, and a visual learner. Mike is At the RANS factory, the Starkeys got to see an S-21 fuselage and tail cone during also a person who organizes in such a construction. Seeing the quality of the construction up close was important. way that makes sense to Mike and no

30 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes It’s not a barn raising, but the hangar is coming together. The huge steel beam for the door support (left) and the hangar coming along nicely (right). The house is already completed. Yes, we got that backward! one else. I look at his “space” and think ready to begin looking for the plane that wanted to do? We started looking at it is an absolute mess, but he knows would be right for us to build. options taking into consideration bud- where everything is. I am a bit of a neat get, time to build, performance and freak and like a clean workspace. Even A Place to Start size—would we be able to fit comfort- before we started I knew the build Before we made the decision on what ably side by side. would be interesting! to build, we had already worked out Once more, timing was our friend. There is also a great support system the where. Mike had designed the While this process of consideration where we live in that there are fellow hangar we built with a workshop to be and debate was taking place, we learned airpark neighbors that have built many able to build a plane if we chose to do that RANS was planning on open- airplanes. We have a great community so someday—that’s thinking ahead. ing up sales of the S-21 Outbound at knowledge base as well as tools available We had the room and the time. Now Oshkosh that summer. We decided for just about any need. We both were the question was this: Is that what we not to make the trek to Oshkosh but

KITPLANES July 2020 31 instead waited until after AirVenture to visit the RANS factory in Hays, Kan- sas. There we would see firsthand if this plane would be a good fit for us! Not only could we try it on for size, but the trip would allow us to have a good look at the factory. So in August of 2018, we headed east with great anticipation. The two days of driving allowed us plenty of time to discuss our options and considerations. Financially, building a plane was within our price range. The desire to build and have our own homebuilt plane was what Mike Starkey (right) takes in the details of the all-metal S-21 wing. A wildland firefighter we really wanted. The flexibility avail- by trade who thinks like an engineer, Mike is no doubt cataloging everything. able when building your own plane is endless…something that I realized after mated to the tail cone in progress and all RANS models and the packaging having the 172 as to how limited you are also a wing in progress. The build area area for shipping to customers. We got on modifications and even working on was very clean and organized. There to speak to Randy and Michele (Shelly) the aircraft yourself. We wanted an all- were several planes in the hangar as well Schlitter, owners of RANS, for a while metal airplane with side-by-side seating, as a completed S-21 that had just come and express our interest in the S-21. the option to pick the engine and prop back from Oshkosh. Mike enjoyed talking to Randy about of our choice and have avionics suited to We finally got to sit down in it. some of the more technical questions our wants. We came to the realization And we both fit just fine! In fact, it he had and was pleased to get clarifica- that so many others have had: Building was pretty cool—the S-21 has lots of tion. The facility is very clean, spacious, was the right choice for us. glass all around us including the doors everyone treated us great—it was a and a skylight, which offers lots of wonderful experience. At the Factory visibility! The doors bubble out a bit It was time for a test flight. We made We arrived at the factory’s opening time (about 5 inches on each side) giving us the trek over to Hays Regional Airport, to have a tour of the facility by Sheldyne some extra elbow room. We also had where RANS has a “flight center,” and Brown. He showed us the area where the opportunity to see the area where met up with Sheldyne, who flew the they had an S-21 Outbound fuselage RANS does fabrication, inventory for S-21 over from the factory. Mike and I

Both Laura and Mike got demo rides in the factory S-21 (below). Despite her concerns that the Rotax would “get it done,” Laura watched Mike and demo pilot, Sheldyne Brown, explore the RANS’s strong runway performance.

32 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes At the RANS demo opportunity, Mike and Laura carefully considered the S-21’s cockpit. Large doors that offer 5 inches of “bubble out” each side (left) and firm, supportive seats (right) gave them confidence that they would fit and be comfortable in an airplane smaller and simpler than their previous Van’s RV-10. each had a turn going for a flight. I got Watching them take off, I was a bit skep- a wonderful meal at the local brewpub. in, buckled up and went flying for about tical that the Rotax could get it done. Lots of time for us to sort through our 20 minutes. The Rotax engine had no But it seemed to have no problem and decision, talk about our flights and problem getting us off the ground. The off they went! finally make the decision to go ahead controls were light to the touch and After the flights, Mike and I had with the purchase. I can’t say the brew- very responsive. I loved it, especially the afternoon to discuss and chew on pub had anything to do with it, but we since I could see all around me! Before our decision. We spent the rest of the committed to the airplane and the build I knew it, we were back on the ground day wandering around Hays, taking a process—which we’ll get right into with and Mike was going up with Sheldyne. self-guided tour at Fort Hays and had the next installment. J

KITPLANES July 2020 33 and ADS-B the Little Guy

If the engine on this Airbike has only a “lighting coil” for the ignition, it is allowed to fly within the Mode C Veil without a transponder or ADS-B Out. ADS-B installation may be avoidable for many small homebuilts. BY RON WANTTAJA

Well, the deadline has passed: As of Let’s take another look at the ADS-B Aircraft transponders provide an January 1, 2020, ADS-B Out is required issue from the point of view of folks like enhanced “echo” to ground radars, and to fly in certain U.S. airspace. myself, who own small, low-performance the altitude encoder connected to the It was accompanied by a lot of excited homebuilt aircraft. The following applies transponder provides altitude to FAA talk about how this is a new advance- only to operations within the United radar sites (Mode C). On top of that, ment for general aviation and all the States—Canadian rules are different. ADS-B Out provides a ton of additional wondrous things that it would do for us. information including, sadly, your air- Maybe so. But most of the coverage ADS-B vs. Transponders craft identification. ignored the financial impact on us little ADS-B stands for Automatic Depen- They are two different devices, but guys, the ones flying $10,000 Pieten- dent Surveillance-Broadcast. ADS-B transponders and ADS-B Out are in pols and $15,000 Kitfoxes. Expendi- Out provides detailed information on lockstep: If you fly in an area where tures that RV or Lancair owners might your aircraft position, speed and alti- you’re required to have a transponder, consider irritating are pretty steep for tude both to the FAA on the ground you must have ADS-B Out as well. The those with entry-level homebuilts. as well as aircraft equipped to receive regulation that covers ADS-B (14CFR Many still don’t know what they’re and display the signals. The ability 91.225) is worded almost identically going to do. Or even whether they need to receive these signals is ADS-B In, to that which covers transponders to do anything at all. which is not required. (14CFR 91.215).

34 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes This works both ways. If you’ve been flying in areas where a transponder isn’t required, you don’t need ADS-B Out, either. When Is ADS-B Definitely Required? Regardless of the airplane configuration or equipment, if it flies in the following areas, it must have ADS-B Out: • Above 10,000 feet, unless you’re within 2500 feet of the ground. • Within Class B airspace (former Ter- minal Control Areas) • Above Class B airspace. Some Class B areas go all the way to 10,000 feet, but others terminate at lower altitudes. The FAA has designated the areas where both transponders and ADS-B Out are required. Aircraft without an electrical system are permitted in the Mode C Veil without the equipment. Regardless, aircraft above Class B airspace must have ADS-B Out. aircraft are now also required to have exclusion for the Mode C Veil refers to • Within Class C airspace (formerly called ADS-B in the Veil. engine-driven electrical systems. Airport Radar Surveillance Areas). However, there is an exclusion: If • Above Class C airspace. Class C air- your airplane was originally certificated Exploring the Exclusion space normally terminates at 4000 feet, without an engine-driven electrical sys- So—what constitutes an engine-driven but ADS-B out is required above it. tem, neither a transponder or ADS-B electrical system? • Within Class A airspace. But when’s Out is required in the Veil. Note that The FAA went through this when the the last time you saw a Baby Ace in this exclusion doesn’t apply to the other transponder requirement was added. the flight levels? areas where ADS-B is required: You still An engine-driven electrical system • There’s also a restriction for flying cer- need it for Class B or C airspace, or to consists of an alternator or generator tain altitudes over the Gulf of Mexico. fly above 10,000 feet. It only applies to mechanically turned by the aircraft Note that ADS-B Out is not required flight in the Veil. engine, a regulator to control the power to fly in Class D airspace (airport traffic The ADS-B requirements are gener- and a battery to store it. If your aircraft areas) unless the Class D is within Class ally the same as those for transponders, does not have all three of these compo- B or C airspace. Otherwise, it’s required but the ADS-B regulation is worded a nents, it’s not officially an engine-driven in the airspace defined above. bit differently. The transponder require- electrical system. ment refers to an engine-driven electrical Some smaller engines have an engine- When Is ADS-B Possibly Required? system, while the ADS-B requirement driven alternator that is used solely The area within 30 nautical miles of the merely says, “Electrical system.” to power the ignition system (“light- primary airport for Class B airspace is The AOPA queried the FAA about ing coil”). These systems don’t include called the Mode C Veil, as it is the area this, and the FAA chief counsel replied regulators or batteries and hence would in which transponder-equipped aircraft that the ADS-B exclusion is the same as qualify for the exclusion as long as these must include an altitude encoder. Most that of the transponder one: The ADS-B components aren’t added. But if they’re added the exclusion no longer applies. Wind generators are not engine-driven so they meet the exclusion requirements. Options for Completed Homebuilts OK, let’s assume you’ve got a RANS or Kitfox flying right now. Do you need a transponder and ADS-B? The answer is obviously “yes” if you need to enter Class B or C airspace. The only point in question is the Mode C Veil. If you live far from any Class B airspace, that question is probably moot. Many small airplanes lack electrical systems and thus qualify for the exclusion. However, Stay out of the airspace, and you won’t the auto engine in this Curtiss replica probably includes an alternator. need a transponder or ADS-B Out.

Photos: Ron Wanttaja KITPLANES July 2020 35 Installing the uAvionix skyBeacon ADS-B Out system was a 15-minute job on the author’s Fly Baby (left). However, it took 3 hours to get power delivered to the wingtip. A battery installed without a generator excludes the airplane from the ADS-B requirement in the Mode C Veil. Charge the battery through an external port as shown here (right). My Fly Baby has an electrical system airplane is completed, you’ll need to very nicely through a flying day, even and is based just seven miles from the include a transponder and an ADS-B two. Some folks say they can get 10–20 primary airport for the SeaTac Mode C Out system. starts from a common Odyssey PC-680 Veil. I could have moved to an airport If not, though, consider: How much dry cell battery. My generator went bad outside the Veil, but its current hangar do you need a generator or alternator in about 20 years ago, and I flew a whole is just a few minutes from my home. The your airplane? summer without it. My Fly Baby has an plane already had a transponder, so I I’m not saying to leave off the radios external jack that lets me easily plug in a only had to install a compatible ADS-B or to steel yourself for a lifetime of hand battery charger between flights. Usually, Out unit. The cost was still about a propping. Leave off the generator/alter- I plugged in the battery to charge during quarter of the value of my airplane. nator and count on using an external preflight and again when I got back home charger between flights to keep the bat- for the day. I never ran short of power. Options If You’re Still Building tery topped off. If you’re building, put in an entire elec- Obviously, if you’re going to need to fly Retain the starter, even without a gen- trical system except for a generator. This is within Class B or C airspace when the erator. A typical aircraft battery will last how you present the airplane to the DAR: Do-It-Yourself Stealth (and How to Survive It) The Government might spend billions of dollars to develop stealth aircraft, but many small-aircraft owners discovered this secret years ago: Fly a no-radio (NORDO) airplane out of an uncontrolled field. Too many pilots don’t look for traffic unless it announces itself on the radio. The problem is just going to get worse with ADS-B. Devices that display other aircraft’s ADS-B Out data are relatively inexpensive and are being installed in a lot of airplanes. There is going to be, sadly, a significant portion of the pilot population that is going to become too reliant on ADS-B information. An aircraft without ADS-B Out is going to ruin their whole day. Your job is to make sure it doesn’t ruin yours. If your aircraft doesn’t have ADS-B Out, keep a careful watch for The basic solution: Fly like you’re invisible. Always assume the those fixated on their displays. other aircraft doesn’t see you. Even if you make the usual radio calls pattern: Waggle wings and yaw around to make sure other aircraft (assuming you aren’t NORDO), some may find a position call without aren’t hidden in your blind spots. It’s a good trick in the ADS-B era, a corresponding ADS-B signal confusing. They may fiddle with the too. If another aircraft expresses uncertainty about your location, display, trying to figure out why you don’t show up instead of looking rock your wings. It changes the light/shadow pattern of your airplane out the window. and catches the eye. If it’s an uncontrolled airport, put your airplane where people ADS-B In can be a very positive tool, and the majority of pilots will expect to see one—use the most common pattern for the field. use it appropriately. However, there are going to be those who fixate I flew from a busy uncontrolled field without a radio for seven on the cockpit display. It’s your neck, too, so be ready to avoid them. years. I used what I called the “NORDO Shuffle” when entering the —R.W.

36 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Culmination of 5 hours’ work and about $2000: a switch on the far left to turn on the ADS-B Out system (left). The unit passed its performance test on the first try. Many low-cost airplanes such as this Boredom Fighter (right) are powered by the Continental A65 engine. Few A65s include provision for electrical systems, which is good for basing within the Mode C Veil but will require hand propping. no electrical system. That way you qualify aspect of the regulation. A transponder include mention of a generator or alter- for the exclusion and can fly within the and ADS-B would then be required to nator, and have removed them to qualify Mode C Veil without a transponder or fly within the Veil. for the exclusion. This, of course, would ADS-B Out. And it’s marvelous how But homebuilts don’t get STCs. Own- violate the regulation. much simpler wiring is when all you have ers can modify the airplanes freely, only to connect is a battery, switch and radio. being subject to Phase I flight restric- Wrap-Up Best leave it at that, though. If you tions if the change is major. Homebuilts The ADS-B Out requirement hurt present the airplane to the DAR with- never get “subsequent” re-certification. general aviation the worst in its most out a generator but carrying a radio, My interpretation is that you could vulnerable area: low-cost, entry-level air- GPS, lights, strobes, and a 200-watt install a generator after your homebuilt craft. Homebuilts or not, many owners amplifier for your Fender guitar, he or has been licensed—and the plane have had to spend a significant percent- she might balk at putting their name on should still meet the letter of the law. age of their airplane’s value to stay legal your paperwork. You’re getting a good You could legally fly within the Veil, if they wished to be based around major break as it is; don’t push your luck. but, of course, still couldn’t actually population centers. enter Class B or C airspace. But the lowest-cost airplanes often Shaving the Edge of the Law However, this could be a hassle. As don’t have electrical systems. Unless you What comes next might be interesting. far as I am aware, the FAA has no pro- actually have to fly into Class B or C air- What if you get your homebuilt licensed cedures to catch people without ADS-B, space, you should be fine. But you’ll have without a generator but add one once unless the plane is communicating with to stay out of the Mode C Veil if you you have an airworthiness certificate? ATC. But if you get ramp-checked, you have an engine-driven electrical system A production airplane would require might have some ’splainin’ to do. In that but no transponder and ADS-B Out. J a Supplemental Type Certificate (STC) case, you’re certainly better off if there’s to document the change, and that no generator on the airplane. would fall into the “…subsequently been I’ve also known people who noted certified with such a system installed” that their homebuilt records don’t

A wind generator can provide a low level of electrical power and does not qualify as an If the generator is left off the aircraft, the electrical wiring is far simpler. “engine-driven” system. (Photo: Ian Cameron)

KITPLANES July 2020 37 Product Review Garmin GI 275 EFIS

38 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes This full-featured, full-priced certified EFIS is impressive but might not be ideal for homebuilts. BY MARC COOK

Let’s cut to the chase here. an STC approval, only certain We’ve been teasing this product antennas are approved, but for since we first had it appear on our Experimentals you can use any collective screens. Garmin’s GI 275 number of the common Garmin is more than a small-scale EFIS, antennas in addition to the more than just an instrument set puck-style antenna Garmin sells for certified aircraft. It’s a tantaliz- for the 275.) For the most part, ing new touchscreen instrument Garmin expects there to be an family originally designed for the IFR GPS on board and that’ll certified world, but that still has provide position and navigation some valuable applications among data to the displays, but the VFR Experimentals. In truth, we prob- GPS can be used as a backup in ably got our hands on an early case the primary fails. The map production set of GI 275 displays displays will all function on the because we can more easily install internal GPS. and test in a homebuilt than wait All iterations have the same for a customer Cessna to get built touchscreen display. It’s true and then go flying. that if you compare raw square So let’s dive in. Garmin has Synthetic vision adds a layer of capability to the GI 275 inches against the G5 or, heaven display. In practice, the feature adds some clutter but a one physical configuration of the combination of high resolution, terrific brightness and sharp forfend, a G3X Touch, the 275 instrument itself, with variations graphics make the presentation functionally excellent. seems to come up short. But based on what is in the box and the display is bright and has which bits of software are enabled. It 110) for integrating with engine and much higher resolution than the G5’s. breaks down to an attitude indicator airframe probes. Garmin’s goal was that Although the data layout can seem a lit- (ADI) starting at $3995; this is known some combination of these instruments tle crowded—definitely no social dis- as the GI 275 ADAHRS. A somewhat would produce a whole-airplane solu- tancing here—the screens are always de-contented version of that same box tion in 31/8-inch instruments. Where easily legible and remarkably capable can be used as a course deviation indi- this meets the needs of Experimentals of fending off glare. You remember cator (CDI) or multifunction display better aligns with those looking to when you got your very first high-res- (MFD); it’s called the GI 275 Base update older aircraft without having to olution computer or smartphone and and sells for $3195. A third version is gut the panel and start over. how dazzled you were by the resolu- the GI 275 ADAHRS+AP, selling for tion? Same deal here. $4495, which has all the functions of Architecture Skeptics among us figured a touch- the ADAHRS unit as well as a supple- Within the GI 275 family, there are screen on such a small instrument was mentary circuit board to provide both commonalities across the variations. For almost a gimmick. I can tell you from digital and analog outputs to drive certi- example, every iteration of the GI 275 hours of setup and flying with the 275, fied autopilots. Oh, and there’s actually has an internal, VFR-rated GPS, though that’s not the case. I assumed that I a fourth version, which combines the GI there’s no internal antenna as you’d find would do most of the work with the 275 Basic display/processor head with a in the Garmin G5. (For the certified concentric knobs. They do repeat much remote box (either the GEA 24 or GEA installations, which are predicated on of what can be done via touch. For example, pushing and holding the center button brings up a sub menu—it’s different depending on the instrument configuration—that you can scroll through either by twisting the inner knob or by touching the up and down arrows. But where the touchscreen really comes into At a minimum, you’ll want the GMU 11 magnetometer (left) but if you want to add its own is on the PFD or primary flight engine-monitoring functions, you’ll need display when you’re actually flying. the GEA 24 adpater (above). More on that in a minute.

Photos: Marc Cook and Courtesy of the Manufacturer KITPLANES July 2020 39 The presentation differences between the G5 (left) and the GI 275 (right) are fairly obvious, though the camera does not do justice to the 275’s screen brightness or resolution. As shown here with the GPS test mode active (note the CDI is half scale left and half scale up on both units), the course info is a little more prominent on the 275 and there are annunciations you don’t get on the ADI version of the G5.

When It Comes to Wiring shared over Ethernet/HSDB. For older number of wires to make that happen will Nowhere is it more clear that the GI navs like the 400/500-series and GNS either make you a temporary expert in 275 is aimed at a very, very broad audi- 480, it’s done over a combination of populating 78-pin, high-density connec- ence than with the interface choices. ARINC 429 and RS-232. Phew! tors or reaching for the phone to call your By and large, radios and instruments In the case of two 275s in the airplane, favorite avionics shop. (In fact, unless you aimed at the Experimental category one is talking to the GPS via HSDB, and work with these high-density products depend on a simplified CAN bus data they’re all connected via HSDB. This often, I recommend having a harness pro- architecture. For example, the G5 architecture allows all units in the net- fessionally made. You’ll thank me later.) sends all the data across CAN—from work to see all the data and afford mul- Each GI 275 also has two RS-232 data the magnetometer and OAT probes tiple variations for display reversion. circuits and one RS-485 channel. That’s to the autopilot servos and the data- What if you have an older nav/com in a lot going on in big connectors hang- combiner box that enables an ARINC the airplane, something that sends analog ing from the back of a 31/8-inch instru- 429 connection to external navigators. signals to an HSI or CDI? The GI 275 ment, with most of them being shielded, Multiple G5s are also connected on the has that handled. You can connect older multi-conductor cables. Every GI 275 has CAN and share virtually all data. nav/coms directly to the 275, though the built-in Bluetooth and WiFi transceivers, Each GI 275, on the other hand, has internal ARINC 429 connections— two channels out, four coming in— meaning that one instrument can be connected directly to multiple nav-data sources. But that’s not how multiple GI 275s talk to each other. Instead, they’re daisy-chained with the HSDB (high- speed data bus), which is also referred to as an Ethernet connection in the manual. Each 275 has two sets of HSDB in and out connections. Moreover, modern GPSes can communicate with the 275 via HSDB; in the case of the GNX 375, which I have, the HSDB carries naviga- tional data from the GPS to the 275, and air data back to the 375 for the internal transponder. For Garmin’s newer naviga- The GI 275 display pair (left) are significantly larger and heavier than the G5 pair (center), tors—the GTN 600/700-series, GNX something to keep in mind for shallow panels. Note the BNC connector on each 275 for 375, GPS 175 and GNC 355—data is the internal GPS. Unlike the G5, you’ll have to connect an external antenna.

40 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Among the multifunction-display modes are the Enhanced HSI (left) and pure moving map (right). Both can overlay weather and traffic, though there are separate displays available for just that data. You can choose to declutter any of these displays from the front panel. enabling a connection to tablets and com- the wide array of options and interfaces baro setting (lower right), altitude bug puters for wireless data transfer and data- available—the GI 275 impresses. Let’s (upper right), airspeed bug (upper left) base updates. You can also wire a USB start with the ADI, which manages and heading bug (lower left). Touching dongle or use Garmin’s GSB 15 USB to stuff a ton of information into one any of these boxes will make them live port/charger. It’s also worth noting that place. It has the normal tape displays for and then the smaller concentric knob the 275 accepts not only nav data from airspeed and altitude, a horizontal tape will change the value; baro is always the external sources but can show traffic and along the bottom for magnetic heading default. I never had trouble jabbing the weather from ADS-B sources, though (when connected to a magnetometer) or display and getting the intended field; there’s no option to connect portables like GPS track (when not). There is a graphi- even though the data boxes appear the GDL 50. You need the GNX 375, a cal vertical-speed indicator but it’s very small, they respond to a semi-accurately suitable ADS-B-equipped transponder small; it is, however, backstopped by a placed finger. Understand that Garmin or the GDL 69 or 69A. small digital presentation nestled into uses a variable-rate scheme here: The the altitude box that proves to be easily faster you spin the knob, the quicker Finally, Let’s Fly understandable after an hour or so. the value changes. It takes practice to Installation complete and the setup Around the four “corners” of the keep from overshooting your desired finished—itself a detailed task given display, you’ll find boxes that show the settings. I found myself overreaching at first because the G5 has a much less aggressive scheme—what I’m used to— and this means making large-scale bug changes requires a lot of twisting. Inci- dentally, if you have two displays and one is configured as an HSI or MFD, changing the heading on the second unit will reflect on the ADI since the heading bug syncs between displays. If that isn’t enough, Garmin has enabled synthetic vision on the ADI and it’s amazingly effective given the screen size. It helps that the pitch scale is somewhat expanded and that the slip/ skid ball is incorporated into the attitude pointer for compactness. (In this way, it’s more like the G3X Touch and G1000 than the G5.) And if it’s all too The GI 275 EFIS has both Bluetooth and WiFi transceivers, enabling full database much, you can choose to declutter the management through the Garmin Pilot app, as well as flight plan transfer functions. display down to a very basic attitude

KITPLANES July 2020 41 Engine monitoring screens (left) can coexist with other functions across all GI 275s on the same network. These include HSI, multifunction displays, as well as displays of weather and traffic. An old-school CDI view (right) is also available. indicator, though after spending on this But this is intentional on Garmin’s part much as possible, hence the layout and, for instrument I’m not sure why you would. because most production aircraft have that matter, the choice to go with 31/8-inch Let’s dive into the ergonomics rolled instruments with some kind of knockout screens that mount from the rear. Indeed, out with the GI 275. For the right-hand- on the lower-left corner, like an altimeter the key advantage the G5 has over the 275 ers in the group, it would seem more logi- or VSI. Even the airspeed indicator in a lot is that the front mounting leaves room for cal to put the knobs on the lower-right of certified aircraft have a true-airspeed a larger display. In practice, you quickly corner—that keeps us from having to knob in that spot. Garmin decided it become accustomed to the knob position. reach “across” the screen for data entry. wanted to ease the installation process as Multifunction, Indeed The GI 275, even in Base form, does a lot. It can be configured as a conventional HSI or CDI, but also can be an EHSI, for enhanced. A moving-map underlay provides situational awareness as well as the conventional compass rose and deviation indicators. That map can show airspace, terrain, weather and traffic simultaneously with the course data. Of course, there are also dedicated screens with just weather and traffic, and simplified versions of navigation displays. How does this work in practice? I used the second GI 275 to repeat ADS-B weather and traffic from the GNX 375. And while the presentation isn’t quite as facile as you’d find with, say, a good-sized tablet, it’s perfectly functional and a nice way to mirror important data from the navigator to a location more in your line of sight. I found myself switching over to the most important screen as needed— radar when navigating through weather, traffic when there was a potential con- At its most basic, the GI 275 when used as a small EFIS needs to be connected to the pitot/ flict. And that’s done easily because the static system and ship’s power. Absent a magnetometer, any headings displayed on the larger of the concentric knobs quickly unit are GPS ground track. moves among the enabled pages.

42 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Autopilots and Engine Monitors The GI 275 is capable of driving just about every form of conventional autopilot out there, all the way back to Cessna wing levelers. It cannot, at this time, drive any autopilot servos directly. Of course, the G5 can, though it does require a control panel to make that feature functional. What does this mean for you? If you have an older installation with, say, an S-TEC autopilot in place, the GI 275 makes some sense. You can remove an older electro-mechanical HSI and not lose autopilot capabilities. This may be a good path assuming the rest of your older autopilot is still in good health. For some owners, it’s cheaper to remove all the old stuff and start fresh with Experimental- class components. But then you have a much bigger job on your hands. As for the engine monitor, that’s beyond the scope of this review. But having looked over the documentation, there’s no reason to believe that the EIS version lacks capability. It is more expensive than a standalone engine-monitor upgrade would be, however. Bottom Line It, Then There’s no doubt the GI 275 is a rugged instrument system and its capabilities far outstrip the G5, coming relatively close to what a G3X Touch can do. But cost is an issue. Let’s look at one example. Updating from vacuum instruments to a pair of G5s is close in cost to adding just one GI 275 with a magnetic heading reference. But the G5 provides basic attitude information and a simplified HSI as your second instrument; you do, however, have complete ADI redundancy. You do not get the crisp, clear moving map, or traffic and weather displays. Capability and flexibility are expensive. Garmin has thrown the prover- bial kitchen sink at the GI 275, giving it capabilities that few installations will ever fully leverage. And most of those are biased toward the certified market, aimed at easing the work of avionics shops having to integrate systems from Cessna 172s to King Airs. Overkill for your average homebuilt? Definitely. A blueprint for future product better suited to our needs? Let’s hope! J

KITPLANES July 2020 43 Aircraft Brakes Some experiences and improvements. BY REINHARD METZ

44 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes My homebuilt has been flying for 21 years now. Speaking with other Experi- mental aircraft builders, it appears many have gone through various brake system changes and upgrades. My experience has been the same—in fact there have been three distinct brake system evolutions on my plane, two of them unfortu- nately triggered by unpleasant events! In this article I will review those evolutions, and perhaps you will find something applicable to your own flying machine. The original Buna-N O-rings were replaced with Viton 75 O-rings. Viton can sustain First Surprise—Heat substantially higher temperatures than Buna-N. One fairly warm summer day I landed to pass by. A quick cab back to my folks I also replaced the MIL-H-5606 brake at Milwaukee’s Mitchell Field to visit and snatching one of their cars, I drove fluid with DOT 5 silicone. DOT 5 is my parents. The landing was followed 100 miles home and the next day came available at many car parts suppliers, but by a rather long taxi to the FBO, includ- back equipped with new O-rings, fluid I recommend checking the web for the ing multiple stops and possibly some and bleeder—a genuine “field repair.” best brands as reviewed by the auto rac- inadvertent brake dragging, which I decided this was not going to hap- ing communities. In any case, you will often accompanies steering a castering pen again. I don’t know what path Cir- be able to find it on Amazon. nosewheel plane. I thought nothing of rus pursued to address their heat issues, While there has been a great deal of it until returning later that evening and but mine was to replace the O-rings, back and forth on the virtues and issues finding two large puddles, one at each which typically are Buna-N (nitrile) of DOT 5, my experience and data add main wheel. How nice—there was all with Viton. I used Viton 75 -222 size for up to a huge positive: DOT 5 is good for my brake fluid on open display, clearly typical Cleveland calipers, but check up to 500° F versus 275° F for standard indicating that this bird was not going yours for the correct dimension. MIL-H-5606. Moreover, DOT 5 does to fly anymore that day! Viton can sustain substantially higher not absorb water. In a car, water intru- Having heard of the heat problems temperatures (-15° F to 440° F) than Buna- sion is much more likely, so auto brake (including some fires) that Cirrus had in N (-40° F to 250° F). Viton O-rings are fluid’s propensity for absorbing water their earlier days, it didn’t take me long readily available from numerous online is an advantage to minimize corrosion, to figure out that the heat of substantial O-ring companies, as well as McMaster- but in airplanes this is much less of a braking, aggravated by tight-fitting Carr. Be sure to go with the -75 series, as concern. In fact, in military applications wheel pants, had flattened the O-rings in the -90 series are much harder and not today, synthetic fluid is preferred. the brake calipers and allowed the fluid suitable for the caliper application. Frankly, I’ve never understood why this red, sticky/gooey, highly flammable MIL-H-5606 stuff has been the persistent fluid of choice in general aviation. Sili- cone DOT 5, which is typically dyed light purple, is non-flammable and compatible with both Buna-N and Viton (although it is not compatible with EDPM). How- ever, most master cylinders use Buna-N. Second Surprise—a Non-Stop On another rather hot day, we made a potty-break “emergency” landing in Michigan, with a very quick stop and rush to the facilities. That done, we hopped back in, and surprise—in the middle of taxiing, the left brake decided to stop working! There was absolutely This homemade bottom-up brake bleeder was pressurized with a bicycle pump and no braking action. After a slight right- worked great! Non-flammable purple DOT 5 brake fluid is much more heat resistant turn diversion through the weeds and a than highly flammable MIL-H-5606 fluid. measured cooldown, a small semblance

Photos: Reinhard Metz KITPLANES July 2020 45 Note that the bolts holding the outer pad assembly are positioned inward, not at the radial center. This causes the outlined area to compress at an angle.

Overtightened bolts can depress soft magnesium, creating an inward chamfer. This causes Outer pad mounting bolts should be care- the outer pad to not be surface parallel to the inner pad, so pad pressure is applied only on fully tightened to spec. These depressions the inner edge. The solution is to re-machine the surface flat and not overtighten the bolts. are signs of overtightened bolts. of braking returned and we were able solution to this event was to machine the lines. At my last annual, I found both to fly home, landing and braking rather caliper surface flat again, and pay partic- of the pilot-side master cylinders were gingerly on the longest available runway. ular attention to tightening the bolts that leaking a bit. That triggered a project The follow-up inspection showed an attach the backplates to the caliper to the that I had contemplated for years and interesting cause: The brake pads were minimum specified torque. In addition, finally got the motivation to do— glazed because they were only mak- my local maintenance expert suggested namely replace the Nylaflow brake ing contact on an edge! The underlying changing to Aviation Products Systems lines with solid aluminum and Teflon/ reason was an angled depression of the (APS) “BlackSteel” rotors and APS pads stainless flexible braid lines at the brake caliper face due to material deformation for better glazing resistance, heat toler- pedals. Despite endless brake bleeding from heat and operation. In other words, ance and overall braking performance. efforts, my brakes had always remained the backplate fixed outer and piston- This was a number of years ago, and I can a little bit spongy, and I always sus- operated pads were no longer parallel. attest that for me these pads and rotors pected a small amount of flex in the In part, this is attributable to the soft- have been a substantial improvement. plastic lines. Further, although the ness of the magnesium caliper, as well as brakes generally stopped the plane ade- likely overtightening of the pad back- Extreme Brake System Makeover quately, they were never as aggressive plates. It turns out that Cleveland calipers My original brake system installation as I would have liked. For example, to are made either of aluminum or magne- included Cleveland 10-20 master cyl- hold the plane fixed at full throttle, you sium, while MATCO or Grove are all inders and kit-supplied Nylaflow brake really had to lay into the brakes. And aluminum, and the soft magnesium can deform fairly readily. (Aluminum calipers are not prone to this problem.) The

Even with tight fitting wheel pants (above), after five years and 500 hours, the Aviation Product Systems “BlackSteel” rotors (right) still look good and are performing well.

46 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes minutes of pushing fluid up through the new and empty system, bubbles stopped appearing in the reservoir and the brake pedals were rock solid! I couldn’t wait to go out for a test taxi and flight—landing, actually! And so it came to be that not only was the sponginess completely gone, the braking performance was in a whole new world, with hugely improved sensitivity and effectiveness. Something else to consider is brake pedal angle. In a certified plane, that design factor has been taken care of. But in your homebuilt, especially with, for example, the MATCO master cylinders where the piston rod end is threaded, you have the opportunity to To eliminate flexing, the original Nylaflow brake lines were replaced with Versatube adjust the length of the master cylinder aluminum tubing, which is very easy to bend and form. and therefore the pedal angle. The trick as my plane entered its 21st year, I also along, I decided at the same time to replace is to find the appropriate median posi- began to get a bit worried about nylon them with MATCO masters, which have tion where you won’t be on the brakes brittleness developing and attendant a slightly smaller piston area and should as you touch down with rudder action, safety concerns. So the non-movable yield greater braking sensitivity. but not so far forward that excessive line replacement was completed with This is a job that includes a substantial foot pivoting is required to activate the aluminum 3/16-inch diameter 3003-O interior dismemberment of the plane as brakes or your shoes interfere with the Versatube, which is conveniently easy well as countless hours of lying under pedal support mechanism. to bend/conform, and flexible stainless the instrument panel in various contor- Lastly, if you look carefully at how steel braid with Teflon inner tubing tions, which is why I had put it off for the top end of the master cylinder is hoses that were custom made by Air- many years! Once done, I moved on to attached, the bolt has been threaded craft Specialty Flightlines. Steve Tsch- the bleeding phase, conducted with my back just a bit to allow the addition of urwald at ASF was incredibly helpful, pressurized bottom-up bleeder. (For a jam nut that allows you to tighten and the hoses fit perfectly. details, see “Homemade Compressed the bolt in place at the fixed mounting Given the master cylinder leakage Air Brake Bleeder,” November 2016.) hole. This way, the bolt does not “work” and somewhat marginal performance all To my astonishment, with just a few inside the hole, enlarging it over time. J

Jam nuts

Keep the braking starting angle back enough to minimize the chances of foot/shoe interference with other mechanical structure (above). Compromise to allow rudder action without activating the brakes. The jam nut on the threaded rod end of this MATCO master cylinder (right) allows you to adjust the brake pedals to the proper angle. Also note the jam nut on the master cylinder attach bolt. It prevents the bolt from enlarging the mounting hole.

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

A plain nutsert installed in a piece of 1/8-inch-thick scrap for testing. Mastering these little beasts. BY PAUL DYE

Let me say right up front that I hate been closed up, so they are often used as joint, but the fastener might be stuck in nutserts. Also called rivet nuts, threaded a last idea for repairs—with the empha- the spinning nutsert—now you’ve got a inserts or rivnuts. (I’m sure there’s a for- sis on last. When it comes to aircraft, I real problem. mal product name in there, but I can’t suggest trying anything else first before I recently had an application for a blind muster the energy to look it up.) These you turn to these things. But sometimes nut that was not going to be solved by vile little devices offer the opportunity to you have no choice. anything but a nutsert. The hold-down install a blind nut plate equivalent with- The problem with nutserts is that they bolts for the rear-mounted battery in out having to access the back side (or tend to spin—that is, once you have my RV-8 are simply long ¼-20 hardware- inside) of the workpiece. Traditional nut installed and pulled them, they don’t store bolts that run the height of the bat- plates require you to have that access, have enough grip on the surface to pre- tery and are fastened with non-captive so they have to be installed during con- vent a careless mechanic from putting nuts on the bottom. This means that in struction. Nutserts—and that’s what I’m enough torque on them while installing order to remove the battery, you have going to call these &#*@ things from a fastener that they lose their hold and to remove the entire rear baggage com- here on—allow you to install a blind nut spin in the hole. Once they do this, not partment enclosure. Many RV-8 builders fastener in the field, after everything has only do you no longer have a working (myself included) have installed a hatch

Photos: Paul Dye KITPLANES July 2020 49 We screwed a bolt into the nutsert to which we applied torque (left). The load cell shows that the nutsert slipped at about 4 foot- pounds (right). in that enclosure to provide battery the nutsert slipped and read the torque. obvious right off the bat that it was going access—but unless you made it particu- The most I saw was 4.0 foot-pounds, to do better. In fact, it did so well that larly large, you can’t get the battery out with an average of about 3.7. That the body of the nutsert never slipped. because you can’t reach those nuts. You comes out to less than 50 inch-pounds. In fact, the bolt kept screwing in to the can’t replace them with an AN4 nut plate Not a whole lot. threaded portion of the nutsert and because the bolt has coarse threads and pulling it toward the head. Eventually, it is hard to find a 6-inch-long AN4 bolt Round 2 with about 14 foot-pounds showing on for a reasonable price. Next, I prepared another hole and another the load cell, I noticed that the bolt was nutsert, but this time I roughed up the turning, but nothing more happened. Nutserts to the Rescue? barrel on a wire wheel and I used five-min- The threads on the nutsert had actually The good part in this situation is that if ute epoxy slathered all over as I inserted it failed! I saw about 16 foot-pounds at the one spins, you can remove the baggage in the hole and pulled it. Given that the peak before this happened. compartment enclosure and remove the temperature in the shop was about 55° F, So, the lesson here is that you can use stubborn thing, so it’s not a disaster. It’s I let it set up overnight. such a device if you add a little epoxy just another horrible inconvenience. How- The next morning, I screwed in my test and recognize that you aren’t going to ever, wanting to be proactive, I thought I’d bolt and started applying torque. It was want to apply a large amount of torque. test the holding ability of the nutsert in a test fixture and see if I couldn’t improve it. The battery mounting plate is actually fairly thick, with 1/8-inch-thick angle aluminum extrusion reinforcements, so I found a piece of aluminum with similar thickness in my scrap bin and mounted it in the vise. I drilled an appropriate-sized hole and installed a ¼-20 nutsert—a generic one from the local hardware store, to be precise, not a branded one. It had a smooth barrel, which doesn’t help its tightness in the hole. After pulling with a typical squeezing tool, I screwed in a ¼-20 bolt and installed a torque load cell on a breaker bar with a 7/16-inch socket. With the bolt snugged up, I began to It is possible to find serrated nutserts that may have more resistance to turning and can apply pressure to the breaker bar until handle more torque, but they’re expensive. (Illustration: Courtesy of McMaster-Carr)

50 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes The second nutsert was installed with epoxy as well as pulled (left). The epoxied nut plate never slipped, but the threads failed at about 16 foot-pounds. Here it is holding at about 14.3 foot-pounds (right). For this application, it will be fine. (But I no nuts of any kind—they just screwed #10, and when those stripped, you put in still hate nutserts!) into the aluminum. They started out as a nutsert and prayed that it didn’t slip. Back in the days of my old Grumman #6 screws and when you stripped those Yeah, I hate nutserts. But, sometimes, Yankee, the aluminum tail fairings were out you went to #8 (on the next annual). you have to use them. And now I’ll use attached using regular PK screws and When those got too loose, you went to them with a little epoxy. J

KITPLANES July 2020 51 Mounting On a Curve SHOP TIPS

Put your GPS antenna where it belongs. BY PAUL DYE

A long time ago, when homebuilders with ever since the airplane was new— work and time, and a 3D scanner/printer began installing Garmin 430s—the most the fact that the antenna got in the way was beyond my means and experience. popular IFR GPS/nav/com of the day— when installing or removing the rear But I could form a shim using fiberglass we were mostly left on our own to install cowl pins. (That’s a consequence of the resin and filler—so that’s what I did. the somewhat large GPS antenna. Gar- “law of changes,” which says anything It really doesn’t take that long—espe- min’s most important instruction was you change when building an airplane cially if it is warm enough to kick off “DO NOT PAINT,” as proclaimed on the will come back to bite you.) So, yeah, I your chosen resin in a reasonable time. antenna itself. Many of us decided that wasn’t unhappy to move the antenna to But, being that I have an unheated shop the easiest thing was to mount them on the fuselage behind the passenger. in the high desert and it was February, a flat shelf underneath a fiberglass cowl, The only problem with this is, of this could have been a problem. I still in front of the firewall—they were hid- course, that the base of the antenna is have some halogen work lights that do den, secure and worked great! flat and the fuselage there is curving. a great job at converting electricity into Then came WAAS and GPS approaches Drill holes for the coax connector, place heat and one placed inside the fuselage with vertical guidance. To get there, you the antenna there and it rocks back raised the skin temperature to about had to upgrade your box to WAAS and and forth with a gap under each side. 100° F—perfect for resin curing. install a new antenna. The new antenna I experimented with pushing it down The process works like this. First, looked just like the old one, but many of tight, and sure—it worked. But it was I drilled holes for the antenna in the us found out that it was far more sensitive clear I was deforming the fuselage skin, skin—both for the coax connector and to interference. And then came ADS-B and this would affect the canopy fit, and the mounting screws. After deburring and the need for solid GPS positions all probably the load-carrying capability of the holes, I taped over the area with clear the time. That the FAA can monitor the the monocoque design. What I needed packing tape. I also taped up the bottom “goodness” of your GPS position makes it was a shim that was flat on top, curved of the antenna and the TNC connector. hard to sweep those “GPS position lost” underneath, fit the antenna perfectly This tape serves as a release plane for the messages under the rug. and wasn’t too thick. I’ve been around shim because the resin won’t stick to it. So, at least for me and my RV-8, it was fabrication long enough to know that I next mixed up just a little resin and time to move the antenna. This would trying to build something out of alumi- added micro-balloon filler until I had also solve a minor vexation I had put up num was going to take way too much a very dry mix—more like putty than

52 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes To start, be sure to tape the antenna base (left) and the coax connector so that it doesn’t get embedded in the shim. Then tape up the curved fuselage section (center). Then mix the resin and micro to a thick consistency and slather it on the antenna (right). toothpaste. I didn’t want it to run at all. I the shim to the antenna with the mount- then slathered the mix onto the antenna— ing screws and nuts and headed to the more at the edges than in the middle disk sander, where I removed the excess because that is how the shim would material and shaped it perfectly to the be shaped. With one smooth motion, I base of the antenna. smooshed the antenna on to the fuselage Then it was back to the airplane, and inserted the mounting screws after where everything bolted right up! I now giving them a light coat of WD-40 so the had a perfect fit of the flat antenna to resin wouldn’t bond to them. I didn’t put the curved fuselage—and per the note nuts on—I just used hand force to push in the Garmin antenna manual, ground- the antenna until I had a nice squish out of ing was not an issue, as it is grounded the goop all the way around, and the cen- through the coax connector. terline of the antenna was almost flush to While getting a good fit for your the skin. Then I went to dinner. antenna might seem like a daunting After about two hours (hey, it was an task, the process really only took about airpark dinner with lots of hangar-flying a half hour, spread out over an afternoon to be done!), I came back and the warm of work—and you can do other things temperatures had hardened the shim while the resin cures. It’s nice to have a nicely. The antenna popped right off due good fit and no distortion of the sheet to the release tape and the shim popped metal—it shows an attention to detail Push the antenna into place until the resin off the tape on the fuselage as well. After and craftsmanship that will impress squishes out all the way around. Now you removing all the tape residue, I attached those airpark neighbors. J wait. Go do something else.

Here’s the untrimmed shim—the right shape is in there (left). Mount the antenna to your shim and carefully sand the edges until they match (center). Don’t worry so much about the inside holes. They only need to be large enough to pass the screws and connector.

Photos: Paul Dye KITPLANES July 2020 53 PLANE and SIMPLE

Support Your Wings BY JON CROKE

Having constructed several high- be challenging. You need a good helper Three popular wing-stand solutions wing aircraft kits, I can attest to the at each end to hold those heavy wings (above): a ladder, a homemade support anxiety that comes from the exercise of steady. You really need a wing stand. and an adjustable post support. mounting wings to the fuselage. This Observing what other builders have process entails hours of carefully align- used for this purpose will provide some aircraft transportation at some point ing those beautiful wings you built to ideas. A couple of questions are in order in the future. And with each removal the now almost completed fuselage. to help you make a good selection. operation there is a need for reinstalla- Measurements must be taken in many How much time or expense should tion. I have used my wing stands more directions to get everything just right: you invest in a tool you might only use often than I ever thought I would. angle of attack, sweep and dihedral to once? After your wings are mounted, If you want to use something already mention a few. While the process is edu- will you ever need the wing stands found in your shop then consider a cational, the effort of making physical again? Yes! You may need to remove stepladder. A common six-foot variety adjustments to such large objects can the wings for painting, maintenance or might work depending on your aircraft

54 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes PLANE and SIMPLE

This 2-ton metal adjustable post stand (left) is adjustable from 4 to 8 feet. The jackscrew provides fine height adjustment. Using the post stand while mounting the wings on a Zenith CH 750 (right). design. It may be too tall—or it may be it addressed the shortcomings of my adjustable posts also save time during too short. Short is OK as you can add ladders and homemade contraptions. the wing alignment process by allowing shims in the form of carpet or cardboard It is called a jack stand or post support fast, precise height adjustments with pieces stacked on the very top step. It is with a jackscrew adjustment on the top. the turn of a screw. worth a try as it is easy to borrow from a Because this stand was fully adjustable This is another homebuilder “tool” neighbor if several are needed. The abil- from about 4 to 8 feet, it provided a uni- that will make you quite popular. Other ity to make fine adjustments in setting versal solution for most any high-wing high-wing aircraft builders in the neigh- the wing height requires adding just the installation. It is overly sturdy and the borhood are sure to want to borrow right amount of shims between the lad- jackscrew allows precise adjustment for your stand from time to time! J der and wing bottom. height without touching the wing. That JON CROKEJON Another popular option is a custom feature is really nice when setting the As the founder of Homebuilt support you make yourself. Whether dihedral. The top fitting provides a con- HELP.com, Jon Croke has from lumber, metal or plastic PVC pipe, venient place to attach a padded 2x4 or you can design and build something similar support for contacting the wing produced instructional videos that fits your specific needs. I still have bottom. Because it can adjust to such a for Experimental aircraft the stands I built years ago. I remember wide range of precise heights, this wing builders for over 10 years. He spending quite a bit of time and trips to support is useful for other purposes has built (and helped others the lumber store to create them. They around the home and shop. build) over a dozen kit were the right size for the job but still The model we used was from Harbor aircraft of all makes and required playing with shims to adjust Freight for less than $80. Keep your models. Jon is a private the wing height. I knew there had to be eyes open for a lighter-duty version a better design somewhere. from other vendors as this 2-ton capac- pilot and One day, Herman, a fellow builder, ity is overkill for our purposes. When currently invited me over to help him detach his comparing the cost in time and money owns and wings for some maintenance work. I spent for constructing a custom wing flies a Zenith realized he was using the ideal equip- stand versus purchasing these post sup- Cruzer. ment for wing stands. I say “ideal” as ports, the decision for me is easy. These

Photos: Jon Croke KITPLANES July 2020 55 BUILDING TIME Murphy’s Law, Occam’s Razor Ed, an aerospace engineer, and Bill, a 14th Century philosopher, walk into your workshop…and if you’re smart you’ll let them stay and you’ll hear them out. They’ll try to support you through your entire project. They’ll offer valuable advice while you fly and maintain the aircraft. And they won’t drink your beer. Well, Bill might. All you have to do to benefit from their presence is heed their rep- etitious words of wisdom.

Edward Murphy Edward Murphy was an aerospace engineer on the MX-981 deceleration tests at Muroc Army Air Field (now Edwards Air Force Base). These tests used rocket- powered sleds and water brakes to test the effects of rapid deceleration on humans. The first tests used dummies. Then John Paul Stapp volunteered to be a dummy. I’m stating facts, not pass- ing judgment. It was Murphy’s idea “I found the problem. You left the master switch on.” Heeding Murphy can prevent to attach strain gauges to record the problems from arising. Embracing Ockham can keep troubleshooting from getting carried away. (Photo: Kerry Fores) forces Stapp experienced during deceleration. The first test failed to deliver holes for fasteners, make sure you have problem, but he was an ardent practi- data because Murphy’s assistant incor- the correct drill bit. Discovering you used tioner of it and his practice was nothing rectly attached the sensor wires. Murphy a #21 bit instead of a #30 after drilling less than explaining miracles. (And you fumed, “If there's more than one way to 200 rivet holes is your failure to confirm, thought fitting a canopy was difficult?) do a job, and one of those ways will result not Murphy stepping in to muck things He is credited with Occam’s razor, “Enti- in disaster, then he will do it that way.” His up. Murphy warned you it could happen. ties should not be multiplied needlessly.” words were distilled to “If something can You didn’t listen. That was William’s Old World way of go wrong, it will.” Murphy’s law was born. saying the simplest answer is most often Murphy is, in my opinion, misun- William of Ockham correct. Thankfully, like the less-than- derstood. His words should not be William of Ockham was a medieval phi- elegant outburst that gave birth to Mur- considered a pessimistic statement of losopher who couldn’t imagine airplanes phy’s law, Occam’s razor is distilled from inevitability; they should be a rally cry being built in garages—for that mat- what Ockham most likely said, “Entia that encourages closer attention to ter, he couldn’t imagine airplanes—but non-sunt multiplicanda praeter necessi- detail. We invoke Murphy’s words after a he knew a thing or two about problem tatem.” He may have been drinking. failure when we should embrace them as solving. Ockham didn’t invent the idea Ockham’s words are not a law or a a precaution. For instance, before drilling of seeking the most logical answer to a theory, they are a razor. The term means

Kerry Fores grew up jumping the airport fence in Oshkosh, Wisconsin. He wanted to build an airplane in 10th-grade woodshop but was asked to choose a smaller project. In 1998, unconstrained by teachers, Kerry scratch built a Sonex he polished and named Metal Illness. It was awarded Plans Kerry Fores Built Champion at AirVenture 2006. Kerry is on the web at www.thelifeofdanger.com.

56 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes exactly what you think it does, “to shave Your thoughts may go to stuck valves, about problem solving. He’ll tell you it away.” Focus on the most likely causes incorrect timing and the possibility of is something you touched, not some- of a problem by eliminating—shav- having to perform intimidating carbure- thing you didn’t. He’ll assure you nothing ing away—the unlikely scenarios. For tor adjustments. broke of its own free will while you were instance, when an engine stumbles to a Because humans are good at worry- trying to make things better. stop it is far more likely to have run out ing, your thoughts may stray to a broken Embrace Bill and Ed as partners from of gas than have had two independent crank and an expensive engine rebuild. the moment you begin building until ignition systems fail within moments of Having ignored Murphy, who tried to the moment you sell your airplane. Their each other. warn you to make sure the spark plug wise words can serve us well, though I wires were reinstalled correctly, you don’t recommend the Latin version of Team Players should embrace Ockham. He knows Occam’s razor as a motivational poster Murphy and Ockham are valuable team nothing about airplanes but plenty for your workshop. J members whether you are building, flying or maintaining your aircraft. Murphy, whose law is rooted in Experimental aviation, reminds us everything must be assured, even the most mundane details. While Murphy encourages us to check everything, Ockham reminds us if things do go wrong it is usually one thing that failed and it is usually the most likely thing that failed. If an engine doesn’t start after a fuel stop it is more likely you (or, ahem, I, in this particular example) failed to turn the fuel valve on than that the engine broke. Murphy anticipated this could happen when I didn’t use my checklist. When it did happen, Ockham wagered I failed to turn on either the fuel valve or the ignition switch. Too often we ignore Murphy, our first line of defense against problems, and have to rely on Ockham’s advice. Ignore Ockham and frustrations rise. Let’s consider the condition inspection. Condition inspections, unlike repair work that targets a known defect, are meant to find and prevent problems that may be developing. Ironically, condition inspections introduce a height- ened possibility of disabling an aircraft. They can disturb the happy existence of functioning parts and sound connections. Example: You replace the functioning, but aging, distributor caps on a Jabiru engine. Your proactive approach is applauded. Murphy, however, right- fully reminds you there may be pitfalls. You may damage or disturb the rotor, loosen or incorrectly replace spark plug wires or install a new-but-defective distributor cap. If the freshly tuned engine stumbles on start-up, Murphy gets blamed with the exclamation, “Now what! I swear, if it can go wrong it does!”

KITPLANES July 2020 57 MAINTENANCE MATTERS Torque Wrench Basics Torque is a twisting or rotational force about an axis such as the length of a bolt. It is measured in foot-pounds, inch- pounds or Newton-meters. These units may also be shown as pound-feet and pound-inches. These are just different ways of saying the same things. When installing aviation fasteners (nuts and bolts), we use torque to determine how tight the connection made by the nut or bolt in question is. We care about this because a bolted connection is designed to retain its tightness when the design load is applied to it without loosening. This is achieved by placing an amount of tension in the bolt or stud that Shown here are various torque wrenches. The beam-type wrench at the bottom works exceeds the anticipated load. If a connec- well for checking the tightness of the alternator belt, but it can be used for many other tion is too tight—that is, over-torqued— torque jobs. The center wrench is a clicking-type, ¼-inch drive. The top is the more generally useful 3/8-inch drive model with a torque range high enough to do prop bolts. the bolt can fail. If it is too loose, it can allow movement in the connection help us much because we don’t have way, you will have to do the conversion. under load that can lead to displacement any way to measure bolt stretch in most However, that isn’t really much bother. of the joint, fatigue and possible failure. cases and have no proven specifications Just remember that 12 inch-pounds Uneven tightness of things such as pro- to utilize if we could. So, we will concede equals 1 foot-pound. When you buy a peller flanges can cause the track of the the point and move on. torque wrench, look for one that will prop to wobble, potentially causing a go up to 75 foot-pounds or 900 inch- host of problems. Thus, achieving the Torque Wrench pounds so you can handle prop bolts. correct amount of tightness in a nut, bolt A good torque wrench is a must for Torque wrenches come in two basic or stud is very important. proper airplane maintenance and types: beam-type and clicking or The question is, how do we best assembly. For many things, a ¼-inch adjustable torque wrenches. There achieve that end? drive torque wrench is very handy, but are now electronic wrenches, too, but The torque wrench is the tool of it will not be big enough to torque spark having a battery in what for most is a choice for aviation fasteners, not so plugs or propeller bolts. You can buy seldom-used tool seems likely to lead much because it produces the best two torque wrenches if you like, but it is to frustration. The beam version relies results, but because the tightness stan- certainly more economical to buy one on the bending of a steel beam to deter- dards we are required to use rely on 3/8-inch drive tool that will cover every- mine torque. A pointer shows torque on torque. Engineers will tell you that we thing. Torque specifications for smaller a fixed scale attached to the beam near should really be measuring bolt stretch bolts are usually listed in inch-pounds, the handle. These tools are inexpensive to measure the tightness of a joint. They, but most 3/8-inch wrenches are cali- and reliable. On the other hand, they can of course, are right, but that doesn’t brated in foot-pounds, so if you go that be hard to read if the item being torqued

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 leisure time building airplanes. He has completed three—a GlaStar, a Glasair Sportsman and a Texas Sport Cub—and is helping a friend build an RV-8. Dave shares his love of aviation with Dave Prizio others by flying Young Eagles or volunteering as an EAA Technical Counselor. He is also an A&P mechanic, Designated Airworthiness Representative (DAR), was a member of the EAA Homebuilt Aircraft Council for six years, and is the recipient of the Tony Bingelis award.

58 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes Use the beam torque wrench to measure how much torque it takes to get the alternator belt to slip. If the pulley doesn’t slip until you have reached 100-120 inch-pounds, the belt is tight enough. is in an inconvenient location. They rep- not so popular. That problem notwith- Hartzell propeller tool is a special crow’s resent good value but lack the conve- standing, clicking torque wrenches easily foot designed to tighten propeller bolts nience of the clicking torque wrench. outsell beam-type wrenches. In any case, on Hartzell (and other) props. This spe- The clicking torque wrench operates one or the other of these is a must-have cial tool attaches to the torque wrench by setting it to a specified torque and tool for an airplane builder. One com- and allows you to apply torque to the then using it as a normal ratchet handle ment about clicking torque wrenches: bolts on constant-speed propellers or until it clicks. At that point, the proper The urge to click the wrench several on other fasteners where a socket will torque has been applied. This type of times for each nut or bolt is almost irre- not fit. When using a crow’s foot, you wrench is more expensive than the sistible for some people. However, all will need to adjust the torque setting to beam-type wrench and requires annual those extra clicks add a little bit of extra compensate for the added length that calibration (and immediate calibration torque, so it is best to click only once and the crow’s foot will contribute. after dropping) but it is very easy to use in move on to the next bolt. Here is the formula for setting your almost any position. These tools are very When it comes time to torque your torque wrench with a crow’s foot popular, but having them recalibrated is prop, you may need a crow’s foot. The extension on it: Tw = Wrench torque setting Ta = Torque to be applied to nut or bolt L = Length of torque wrench E = Length added to wrench by crow’s foot extension Tw = (Ta x L) / (L + E) Here’s an example. Suppose we wish to apply 50 foot-pounds of torque to a propeller bolt. What wrench setting should we use if our torque wrench is 15 inches long and our crow’s foot extension adds 3 inches to the length Crow’s feet of various sizes can be used in places where it is not possible to use a socket. of the wrench? The Hartzell propeller tool shown on the right is a special kind of crow’s foot made just for Tw = (50 x 15) / (15 + 3) torquing the ½-inch bolts on a Hartzell propeller. Tw = 42 foot-pounds

To calculate the adjustment needed to compensate for the use of the propeller tool, you need to measure the distance from the center of the ratchet drive to the center of the bolt and then measure from the center of the ratchet to the center of the handle. Here we have 3 inches from the bolt center to the ratchet drive center and 15 inches from the ratchet to the center of the handle.

Photos: Dave Prizio KITPLANES July 2020 59 In other words, set your torque wrench to 42 foot-pounds to apply 50 foot- pounds of torque to the prop bolt. Be sure to use the same units for the length of the wrench and the length of the extension. They can both be in inches or they can both be in feet. Just don’t use feet for one and inches for the other. The premium tool makers produce torque wrenches with open-end wrench attachments that work really well for things like prop bolts, but they are pretty expensive for Experimental airplane builders. Sometimes you can find a good used torque wrench of this type for a reasonable price, but most of us Here a ½-inch drive torque wrench and a Hartzell prop tool are used to torque the bolts will have to forego such a luxury and on a Hartzell propeller being installed in a Glasair Sportsman. Be sure to follow the prop manufacturer’s installation instructions when installing a propeller. just use a crow’s foot. fasteners at overhaul. These recommen- torque tables in aviation handbooks Fasteners dations should be followed. are based on clean, dry threads. Engine To properly tighten a fastener, it is Here is a good test for a fastener. You fasteners are another matter. Lycoming imperative that the nut, bolt or stud should be able to easily thread a non-lock- specifies that engine bolts be lubri- are in good condition. That means that ing nut onto a bolt or stud with no notice- cated with a mixture of engine oil and there are no damaged threads or nicks able drag or hang-ups. A good nut should 10% STP. Other engine manufacturers or worn spots on the fastener. An avia- easily thread onto a known good bolt have their own thoughts on this. The tion fastener should have its original with very little effort. If you can do this, point of lubrication is to reduce fric- cad plating intact and it should be your fastener’s threads are acceptable. tion between the bolt or stud and the clean—free of oil, dirt, or other foreign Aviation nylon-insert lock nuts pres- nut. This friction is a potential source substances. Fasteners with minor thread ent a special case. The FAA says that of inaccuracy in bolt tightness as deter- damage can be restored with thread- those nuts should be replaced when mined by torque. High-performance chasing taps or dies. You should never they lose their ability to prevent the automobile engine builders typically use a thread-cutting tap or dye to restore nut from loosening. However, there are use lubricated threads and bolt stretch threads on an aviation fastener because no specifications for how much locking measurements to determine tightness they remove material, especially at the force they should apply or how to mea- whenever possible. This is much more critical thread root. The best advice is sure it. Again, we are left with the advice accurate but generally not available to when in doubt, throw it out. Do not to discard and replace any nut that has aircraft engine builders. reuse questionable fasteners, especially questionable locking ability. For aviation mechanics, the point is to in critical areas. Engine manufacturers Most torque numbers are given be sure you know and follow the engine will often recommend replacing critical for clean, dry fasteners. The standard maker’s specifications when it comes to lubricating threads (or not) and measur- Torques for Fine Thread Nuts and Bolts by Bolt Size ing torque when assembling an engine. Standard Nuts – Shear Nuts – Do not use generic torque tables for Bolt Size AN310, AN363, AN365 AN 320, AN364 engine bolts. Refer to the Lycoming Overhaul Manual or a similar publication 10-32 20-25 in-lbs 12-15 in-lbs by the engine maker for the engine you 1/4-28 50-70 in-lbs 30-40 in-lbs are assembling or repairing.

5/16-24 100-140 in-lbs 60-85 in-lbs Standard Torque Table for Aviation Fasteners 3/8-24 160-190 in-lbs 95-110 in-lbs When there is no other specification available for torque you can use these stan- 7/16-20 450-500 in-lbs 270-300 in-lbs dard numbers from the chart on the left. 1/2-20 480-690 in-lbs 290-410 in-lbs Nylon insert lock nuts and all-metal lock nuts present a special problem. How Reference: Standard Aircraft Handbook, McGraw Hill, 1999. much torque does it take to overcome

60 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes A short extension is needed to clear the baffles on the O-360 engine (left). By keeping the extension as short as possible, there is less chance to introduce inaccuracy into the process. Especially on many RV models, there is insufficient clearance to get a socket and extension into position to torque the spark plugs for cylinders Number 3 and 4 (right). In this case, a crow’s foot and an aviation spark plug socket will do the trick. the resistance of the locking insert? snug, then switch to the torque wrench. As a general rule, I prefer to use the There is no known specification for this, Remove bolts with standard wrenches or shortest extension possible in cases and it varies as the nut is used again and ratchet and sockets. where one is required. The longer the again. I did my own study to determine Often the maker of a part will specify extension, the more there is a need to the torque to overcome nylon inserts in that a nut or bolt be tightened in stages. stabilize the head of the wrench with lock nuts, but this has no official status This is especially common when mul- your other hand. This can introduce inac- and did not consider all-metal lock nuts. tiple fasteners are involved, such as curacy. In some cases, this is unavoidable Here is what I found: with a propeller or an engine cylinder. but do your best to minimize the use of The procedure would be to first snug all extensions wherever possible. Nut Designation Drag nuts or bolts, then torque to one-half the Lastly, be sure to have your torque AN365-1032 4 in-lbs final value using a cross pattern. Finally, wrench recalibrated from time to time. torque to the final number, again using A professional mechanic should do this AN365-428 10 in-lbs a cross pattern in the case of multiple yearly. For an amateur builder who only fasteners. Be aware that engine manu- uses a torque wrench two or three times AN365-524 15 in-lbs facturers often have torquing sequences a year, this is probably overkill. But if you AN365-624 20 in-lbs that are not necessarily obvious. Read have never had it done, it is high time to the book and follow it. do something about that. J This drag torque should be added to the specified torque to achieve the proper torque at the fastener. For example, add 10 inch-pounds of drag torque to the listed 50-70 inch-pounds of torque for a ¼-28 nut to achieve the prescribed tightness at the joint.

Using a Torque Wrench Torque wrenches should be calibrated annually or after being dropped on a hard surface. An uncalibrated wrench cannot be relied upon to deliver the specified torque. Even though most torque wrenches come with a ratchet head that can be used to tighten or loosen a nut or bolt, they should never If nuts that are hard to access will require the use of a long extension, it’s important to be used to loosen anything. Use a stan- stabilize the wrench to apply the proper torque. Here, Lycoming 5/16-18 exhaust nuts are dard ratchet to tighten bolts at least to being torqued to 204 inch-pounds as per the Lycoming Overhaul Manual.

KITPLANES July 2020 61 OUT OF THE BLUE COVIDity Blues As I write this, it is the Ides of March in the year that will live in infamy. We are all aviators or we wouldn’t be reading this magazine (my favorite and I get several). In the 35ish years that I have earned my income flying airplanes, this is about the fourth time I’ve witnessed the dark side of the pendulum. Even though I have faith that it is only temporary, it is fright- ful to watch the 401k rapidly descend through 301k on its way to 201k. Hope- fully by the time you read this, this horrible state of affairs will have abated or at least turned the corner. Maybe not. The prognosis seems to change by the hour. I just completed an airline assign- ment. There’s a chance it may have been my last. I’ve been lucky and blessed. World’s best job in the world’s worst industry. Time will tell. Coming to work was surreal. A lot of similarities to 9/11 Precious cargo! Unexpected problems often lead to unusual opportunities. Visit www. but much scarier in some ways. The kitplanes.com/covidity and post a caption for this photo in the comments below the story. The winner will receive a free one-year subscription to KITPLANES®. 9/11 attacks were man-made. This one is nature. I’m not quite sure which is senior and could even hold captain if a necessary break from the bleak. A worse at this point. In the pilot lounge he wanted to, but was enjoying being refreshment, a blessing. of our domicile, one of our pilots got a near the top of his bid category. We Then out of the blue, we had a hard text from his son saying that his regional exchanged the usual pleasantries and slap back to vivid reality. On the next airline was shutting down. My son came chitchat. I was not looking forward to (last) day of the trip, we left KMDW Chi- from a regional to my airline a few years talking about depressing things. Then it cago Midway airport for a short “turn” ago. I worry about the young and junior came to light that my FO was building to KCVG Cincinnati and back to Midway and hope they have the same opportu- an RV-14. Hallelujah! before the last leg back to Phoenix. The nities that I enjoyed. For the next several hours and legs, departure and flight to Cincinnati was On the first leg I was paired with some- we talked all things Experimental air- quick and easy, but upon arrival and try- one quite junior who obviously had craft to death. We talked about kits, we ing to get our clearance back to Midway, concerns about career security, which is talked about engines. We talked about we were told that all flights to KMDW normal and never fully appreciated until avionics, building, painting, flying and were grounded because controllers in it is lost. I tried to be as upbeat as I could maintaining. Lots of stories, most of the tower had tested positive for the as we talked about a lot of potentially ugly them true. virus and so the tower was closed. Our scenarios. It was sobering. It was painful. It was sunshine to my soul. It was flights were canceled and ourselves and Later in the sequence, I was paired calming, therapeutic, even cathartic. a lot of our passengers were deadheaded with a different first officer. He was quite For those hours, at least for me, it was to Denver and beyond. I must confess

Myron Nelson soloed at 16 and has been a professional pilot for over 30 years, having flown for Lake Powell Air, SkyWest Airlines, and Southwest Airlines. He also flies for the Flying Samaritans, a volunteer, not-for-profit organization that provides medical and Myron Nelson dental care in Baja California, Mexico. A first-time builder, Myron currently flies N24EV, his beautiful RV-10. He has also owned a Cessna 150 and a Socata TB-9.

62 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes that I’m not much of a fan of riding in to the airport and hang out in the han- the back. I’m spoiled by the view and gar with the RV-10. I can’t explain it and more comfortable seat up front I guess, it may sound corny to some, but it gives and boy you notice someone coughing me peace. I decided to accomplish the nearby now more than ever. service bulletin on the nose gear leg, and I wasn’t flying on the day of 9/11. I while I had its forward parts undressed, had actually just finished a trip the night clean my fuel injectors via Paul Dye’s before. That day was surreal, too. I owned recent explanation of how to do so. a Socata aircraft at the time and even We are all part of this avocation though I couldn’t fly it because of the because there is a passion within us that closure of all airspace, I just wanted to be we can’t explain but is very real. Bad men around it. I had received a service bulle- or bad times can disrupt our plans but tin, so I decided that afternoon to go to can’t disrupt our dreams if we don’t let the airport and check out the airplane them. Some of us have flying airplanes, and the service bulletin. There were no and some have kits in varying stages of security fences at most general aviation completion. Some are just wannabes, airports in those days, so anyone could and we’ve all been there. Sometimes we just drive up to the airplane, which was have it all and sometimes we just have a parked in a covered tie-down. The service stack of magazines and catalogs to stim- bulletin involved checking the seat pans ulate our dreams. of the front seats. Flashlight in hand, I was The world may appear to be losing door up—legs sprawled out on the wing its mind, but this craziness will pass. It and torso contorted into the footwell to always does. No doubt some of us are inspect the seat pans from an upside- going to be severely impacted. Projects down perspective. Firmly pretzeled in, I stalled. Aircraft sold. Orders canceled or heard two cars pull up at high speed and deferred. It’s a gut punch. Nevertheless, screech to a stop. I considered looking to we are all part of a vibrant and enrichen- see who it was, but the yoke I was under ing community of similar interests and prevented that, and for a brief moment passions, and one of the things that we gravity, physics and human physiology do best is support each other. Once we were not my friends and I feared that I can meet in groups again, let’s make was stuck. Then I heard a stern command a concerted effort to attend our EAA to exit the aircraft with my hands up! chapter meetings. Let’s make the next Rut-roh. available Oshkosh and other airshows I yelled back that I would love to, but the best ever. We will get through this. I was stuck and needed a hand. This We mustn’t let the fire in the hot section brought a firm grasp to the back of my flame out for ourselves or each other. shirt and a yank that left a scratch on As much as I love my RV-10 and con- the wing from my belt buckle and a sider it the most versatile general avia- bump to the back of my head from the tion aircraft I’ve ever flown, for some yoke—both of which probably remain to time I have been considering building this day. As officer Laurel extricated my another aircraft, even though I haven’t felonious hiney from the aircraft, officer decided which one or even what type. I Hardy pointed his weapon in a way that like all types. Maybe an RV-15 of which I made us both uncomfortable. Thank- know nothing about. If they announced fully, my airline ID was in my car and my it tomorrow, they would have my deposit registration was in the airplane, and I same day. This wretched COVID-19 mess assured them that “Death to America” has pushed me from maybe building to was not in my vocabulary or intentions. absolutely building. Building gives me We actually shared a good laugh at the peace. I go to church but I hope there are end and joint bewilderment for the blink hangars in heaven, too, because mine is a of an eye that was rapidly moving our sanctuary on earth to me. respective cheeses. The grim reaper can have my rivet gun Fast-forward almost 20 years and first when he pries it from my cold dead fingers. thing I wanted to do today was go out Build on mates, even if only in dreams. J

Photo: Myron Nelson KITPLANES July 2020 63 HOME SHOP MACHINIST Lightweight Stepladder I affectionately refer to my Jabiru light-sport as being a “low high-wing” airplane. This is because, despite it being a high-wing configuration, you have to stoop pretty low to walk under the wings. On the plus side, I don’t need a full-size ladder to get above the wing to visually check the fuel level. I do need a boost, and for the longest time it’s been via a section of a liquidambar tree trunk. Although it happens to work fine in the hangar, it is too heavy (24 pounds) to take with me. While it hasn’t happened yet, I would be in a bind if I needed to check the tanks or refuel at a remote airport with no ladder. The commercial stepladders and step- stools I looked at were either taller than I needed or looked too cheap. It didn’t take long before I started to envision The 24-pound woodblock stepstool (left) and its replacement, a lightweight, sturdy and what a homebuilt stepladder might look compact home-shop stepladder (right). like: very simple, about a foot tall and a Exploded view shows the mere 2 pounds. simple construction. The The tools and construction techniques back legs are welded to the for the project included lathe work for top after confirming assem- the bolts and pins, mill work with the bly and alignment. A full indexer for the aluminum pivot bolts and set of PDF-format design drawings are available at nuts, basic tap and die threading, sawing, www.kitplanes.com/ some drilling, sheet-metal bending with stepladder. a pan and box brake and TIG welding. Like many of my “not going to the moon” projects, I designed my stepladder based on material I had sitting around the shop. I happened to have some 1x1.8x0.062-inch rectangular 6061 aluminum tubing that was originally extruded for a mountain bike frame. I used this material for the legs. Since no one is likely to come across this particular tubing, I changed the drawing to make the legs using standard 1x2x0.062-inch 6061 aluminum rectangular tubing.

Bob Hadley is the R&D manager for a California-based consumer products company. He holds a Bob Hadley Sport Pilot license and a Light Sport Repairman-Airplane (LSRM-A) certificate.

64 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes The top was made from 12x24x0.073- inch aluminum diamond tread sheet from Home Depot. Like the leg material, this was a leftover from another project and not purchased specifically for this stepladder. The stretcher braces and reinforcing channel for the top were made from 0.040-inch 6061 aluminum sheet. The pivot bolts, nuts and alignment pins were made from 6061 aluminum bar stock. The rivets for the leg angle brackets (six rivets) and channel brace (four rivets) are 1/8-inch aluminum flush pop rivets with a 0.25-inch grip length. The rivets for the long stretchers that connect the legs in pairs are standard 1/8-inch steel pop rivets The top and two angled brackets that provide inboard support for the legs were made (eight rivets) with a 0.25-inch grip length. by adhering full-size paper patterns to the sheets with Spray Mount, then cutting to They are the only steel parts on the ladder. shape using a band saw.

With the paper pattern still adhered to the smooth side of the diamond tread sheet, the sides and ends were bent using a pan and box brake.

Photos: Bob Hadley KITPLANES July 2020 65 To save weight, instead of traditional scissoring braces for the pivot mechanism, 1/8-inch nylon ropes were tied off at the correct length and sleeved with a nylon bushing in the aluminum legs. You will note from the photos that one set of legs are TIG welded to the top. I considered using screws and/or rivets to fix the non-pivoting legs to the top, but welding seemed to be the best option. Of course, you need to be able to weld or know a good welder… my ladder is welded because I happen to know Billy Griggs, an ace welder with A coolant-fed, low-rpm “cold saw” with a fine tool blade was used to make the cuts on the tons of experience welding lightweight legs. A digital protractor was used to set the angle to 20°.

Drilling the legs and top for the pivot bolts and alignment pins. Note the top was drilled after the bends were made.

A sander with a 120-grit disc was used to radius the corner of each leg concentric to the pivot hole (left). The legs were then clamped in the mill, and the five evenly spaced lightening holes were made using use a 7/8-inch hole saw. The long stretchers that go between each leg were notched on the band saw (right), then bent into a channel using the pan and box brake.

66 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes aluminum structures (Billy builds custom bike frames and was the source of the leg material). I originally did not include the channel brace to reinforce the top. It was added after initial use caused the top to sag under my 180 pounds. Adding the brace increased the strength to where a 220- pound person can stand on it with no noticeable deflection. Be sure to visit www.kitplanes.com/ stepladder for detailed design drawings for the machined parts as well as flat pat- With the angled bracket for inboard support positioned and riveted to the top, the terns (with bend lines) for all the sheet previously drilled holes in the top and leg were used to align and drill the bracket. To metal parts. That’s it for now. Time to get ensure everything lines up for the final assembly, use a different leg to drill each hole back in the hangar and use my new step- and mark them so they don’t get mixed up. ladder to check my fuel level! J

Detailed views of the fixed legs welded to the top and support bracket. Note the alignment pin is also welded. The pivoting bolts and nuts are 6061 aluminum. At final assembly, add a dab of red Loctite threadlocker and tighten just enough to preload the legs so they stay in position when folded or extended.

To complete the step- Detail of the nylon rope and bushing. It took a few tries to get the knot positioned so ladder project, two red “don’t step here” the legs extend in the correct position with the rope taut. stripes were painted on the top.

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KITPLANES July 2020 71 AERO ’LECTRICS VHF Com–the Good, the Bad, the Ugly With a panel full of glass and diodes spread spectrum would require every air- has the capability of transmitting on turned into all the colors of the rainbow, craft and every ground station to switch 760 discrete frequencies does not mean the poor old VHF com sitting over in the over at precisely the same moment. Hav- that you have the right to use any or all corner of the panel doesn’t have quite ing a 737 depart from SFO on AM at sun- of them. It’s the same way with cars: Just the pizazz it once had. I have vivid recol- set and landing at JFK the next morning because you own a Miata that can hit 120 lections of swapping my old 3-channel at sunrise on FM during the swap-over mph doesn’t mean you can blow through Narco Homer for a spiffy new VC-27Z just isn’t going to happen. I think good a school zone at that speed. with (gasp) 27 crystal-controlled trans- old Ancient Modulation is going to be Let’s talk for a moment about how mit channels. I proudly hacked the alu- with us for the foreseeable future. much room we have in the com band. minum panel to fit that radio into the One of the greatest drawbacks to AM First of all, the band goes from 118 MHz at Cessna 120 Heavy (we were 20 pounds is the fact that it requires a carrier (which the low end up to (but does not include) over gross on most occasions) for a mon- is the frequency you dialed up on your 137 MHz at the top end. Most of the world umental trip from San Diego to Boston. radio) and two “sidebands” that actually has divvied that 19 MHz of bandwidth It was sort of fun racing the Santa Fe carry your voice. Each of those sidebands up into 760 discrete frequencies sepa- Super Chief from town to town. We actu- at best have one quarter of your radio’s rated by 25 kHz spacing. For example, we ally won about half the contests. power, and you can only hear at the can have 123.0, 123.025, 123.05, 123.075 But I digress. A brief history of air-to- receiver what is on one of the sidebands. but not 123.021. The exception to this is ground communications shows a crude Thus, your rock-crusher 10-watt radio you Europe, which has split each of these 25 form of amplitude modulation com- paid kilobucks to buy can only have the kHz spacings into 8.33 kHz spacing, giv- munications in 1912. Crude being turn- equivalent of 2.5 watts of “talk” power at ing three times the number of channels ing the transmitter full on and then full the other end’s receiver. And vice versa. (2280 total). Why? Because at 35,000 feet off for long or short bursts spelling out I’d like to take you through a brief walk on any given frequency in Europe, you words in Morse code. This was followed of the current state of affairs on the air- are within range of 16 different countries. shortly in 1915 with a more sophisticated craft VHF com band and see just who is Keying up your transmitter over Belgium amplitude modulation that actually assigned to what frequency or groups of lets you get into radios from Switzerland allowed voice to go between ground frequencies. I hate to be the bearer of bad to Sweden without any trouble. Hence and the aircraft. news, but just because your aircraft radio they needed more channels, and the Why amplitude modulation when almost all forms of voice these days is either FM or some sort of spread spectrum digital modulation? In the first place, Edwin Armstrong didn’t invent FM until 1933. In the second place crude spread spectrum didn’t appear until actress Hedy Lamarr invented it in 1941 to keep the Axis from jamming the guidance of Allied torpedoes. Modern spread spectrum has only come along in the last 15 years. Finally, to switch from the current AM (sometimes jokingly referred to as Designed specifically for Experimentals, Garmin’s Bluetooth-enabled GTR 200B com radio “Ancient Modulation”) to either FM or has 25 kHz channel spacing and includes a built-in intercom. (Photo: courtesy of Garmin)

Jim is the chief avioniker at RST Engineering. He answers avionics questions in the Maintenance Bay section of www.pilotsofamerica.com. His technical advisor, Cyndi Weir, got her master’s degree in English and journalism and keeps Jim on the straight and narrow. Check out their Jim Weir website at www.rstengineering.com/kitplanes for previous articles and supplements.

72 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes only answer was to make finer divisions Audio (“modulation”) tone of what was there. Here are a couple of interesting sidelines: • There is only one frequency that still has 100 kHz spacing—121.5 (the emergency frequency) is protected from 121.4 to 121.6 MHz. For example, there is no permissible transmission on 121.45 or 121.55. • In 1990, the top end of the com band was increased from 136 to 137 MHz, an addition of 40 channels. The initial proposal was to give 10 of those channels to the Unicom frequencies that were jammed into eight frequencies across the entire country. Then the airlines said, “We need a lot of these new RF (“carrier”) wave frequencies.” Then the FAA said, “We need a lot of these new frequencies.” I Looking at what an AM signal would look like on an oscilloscope. This shows an RF carrier think you can see where we are going. wave (blue) being modulated by a constant-frequency audio tone. This amount of modula- Out of this mess we got…our original tion (about 50%) reduces the amount of detectable signal in a distant receiver by a factor of 8:1. That is, if the transmitter is a one-watt transmitter, there are only 125 milliwatts of the eight frequencies. audio tone being transmitted. The maximum that you can have (even if the modulating So, without further ado, here are some tone is turned up to go all the way up to maximum and down to zero) is a reduction of 4:1 interesting factoids derived from 47 CFR for either the tone on top or the tone on the bottom (upper and lower side-bands). Part 87 (the FCC Aviation Regulations). Letters designate the subpart if you 123.05 and 123.075. Note that 122.95 is available for flight testing of aircraft or want to look up the actual regulation. only allowed at an airport with a tower or components, and they are used by manu- Subpart F (Aircraft) are authorized to an FSS. There can only be one station at facturers of aircraft or major components use 122.75 for fixed-wing air-to-air com- any one airport (first come, first served). and educational institutions engaged in munications and 123.05 for helicopter Subpart H (Multicom) is for any airport flight testing. Allocated frequencies are air-to-air communications. These are not eligible for Unicom. The frequencies 123.175, 123.2, 123.225, 123.375, 123.4, the only legitimate air-to-air frequen- 122.85 and 122.9 are available. 122.925 is and 123.45. (Note that 123.4 and 123.45 cies available to general aviation aircraft available for forestry, fire, fish and game, are only available to stations that have to including Experimentals. and environmental reasons. move from location to location.) Also note Subpart G (Unicom) at a public-use air- Subpart I is a service for airlines. that aircraft are only authorized to contact port is allocated eight frequencies: 122.7, Subpart J is for flight testing (please ground stations on these frequencies and 122.725, 122.8, 122.95, 122.975, 123.0, read carefully). These frequencies are not air-to-air communications. Aircraft manufacturers are also authorized to use Carrier Amplitude 120.0 MHz. frequencies from 123.125 to 123.575. Each @ 1 watt application for a license must go through a frequency coordination committee and be approved individually, and a separate license application and fee must be paid. Subpart K is for flight schools, gliders and balloons. Frequencies available are 122.95, 123.3 and 123.5. Lower Upper Subpart L is for mobile ground vehi- Sideband Sideband cles on an airport. They may be autho- 199.998 MHz 120.002 MHz rized for any tower, ground, Unicom or @ 1/4 watt max. @ 1/4 watt max. Multicom frequency. Subpart M is for search and rescue. Frequency Frequency available for actual search/ This is what a spectrum analyzer would see if the RF carrier wave were 100% modulated rescue is 123.1 and 122.9 for practice. by a 2 kHz audio tone. Note that either the upper or lower sideband only has 25% of the One last note that came to me from carrier power due to modulation. The receiver can only detect one of the sidebands. a newsgroup recently: Some countries

KITPLANES July 2020 73 prohibit even a receiver on the aircraft By this time next month (the weather band to be in your possession. One fel- gods willing in Northern California), low traveling to Greece faced 25 years in I’ll have a lot more to share with you the slammer until diplomatic channels about 12-volt hangar power from our pulled him out. Beware of traveling with old friend Sol. your handheld. Until then…Stay tuned… J

Carrier Amplitude 120.0 MHz.

Lower Upper Sideband Sideband

^ ^ ^ ^ -3 kHz. -300 Hz. +300 Hz. +3 kHz. Frequency This is what a spectrum analyzer would see if the RF carrier wave were modulated with a human voice with a filter to cut out all of the voice energy below 300 Hz and all of the Beware of traveling with your handheld— voice energy above 3 kHz. This is called “telephone quality” audio and specifically filters they aren’t legal in some countries. the voice for maximum intelligibility on the receiver end. (Photo: courtesy of Sporty’s Pilot Shop)

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74 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes WIND TUNNEL Design Process: Span and Aspect Ratio At this point in the design process you will find in any text or technical that the nondimensional induced drag we have determined the wing area. The report, so it is used here.) coefficient is a function of aspect ratio: 2 choice of high- versus low-wing and Cdi = CL /(Π e AR) structural concept of the wing are estab- Induced Drag This nondimensional coefficient is lished. We can now turn our attention to Induced drag is the portion of the drag of what most of us are familiar with. To get details of the planform. the airplane that is a direct result of the actual drag from drag coefficient, we The most fundamental design deci- production of lift. It is a function of the need to multiply the coefficient by the sion at this point is the choice of span and span of the wing and the amount of lift wing area and the dynamic pressure. aspect ratio. These two parameters are the wing is generating. It’s common to I will spare you the algebra here, but mathematically linked together. Once think that induced drag is determined by when all the manipulation is finished, we we have chosen the wing area, the span aspect ratio, but this is not the case and get the equation for actual drag shown automatically determines the aspect that misconception can be a trap for the above, in which the span remains but the ratio and vice versa: unwary wing designer. aspect ratio does not. AR= b2/S The actual induced drag of a lifting The important thing to remember is And conversely wing (in pounds, or Newtons depending that for a given lift, density altitude and b=sqrt(S*AR) on unit system) is given by: airspeed, all wings of the same span will 2 2 Where: Di =L /(Π q e b ) generate the same amount of induced b = wingspan Where: drag regardless of wing chord, area or S = wing area q = dynamic pressure of the airflow aspect ratio. (Note that the use of “b” for span and e = span efficiency More than one designer has made “S” for area are standard engineering Dynamic pressure is proportional to the mistake of making the wing area of notations in aerodynamics. I don’t know airspeed squared and the density of the an airplane smaller to reduce wetted the history of this, but it is the standard air. The reason for the misconception is area and decrease drag and ended up reducing wingspan at the same time, even though the aspect ratio of the new, smaller wing is higher. This usually ends up with an airplane that may be faster at low altitude due to the decrease in wetted area, but climbs poorly and flies slower at cruise altitude due to the increase in induced drag caused by the reduction in wingspan. One example of this was a NASA- sponsored program to investigate advanced technologies for general aviation. The program started with a Cessna Cardinal and replaced the stock wing with a much smaller wing incorporating sophisticated high-lift devices to keep The highly tapered wingtip extensions on this RV-6 improve cruise performance at the stall speed down, an “advanced” altitude. The reduction in induced drag due to the span increase is greater than the airfoil, and spoilers for roll control. The drag of the added wetted area of the extensions. (Photo: Barnaby Wainfan) “advanced” wing had just over half the

Barnaby 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 Barnaby Wainfan design of unconventional airplanes including canards, joined wings, flying wings, and some too strange to fall into any known category.

KITPLANES July 2020 75 For the latest version of the 777, the induced-drag benefits of greater span were large enough that it was worth it to Boeing to engineer folding wingtips to allow the span to be extended beyond what is compatible with most airport gates. The folding tips allow the airplane to use standard terminal gates and have a longer span in flight to improve cruise efficiency. (Photo: Dan Nevill from Seattle, WA [CC BY https://creativecommons.org/licenses/by/2.0]). area of the stock wing, and even though • At the airspeed for minimum power relatively large span that comes from its aspect ratio was higher than the stock required to fly, which corresponds to their large wing area. wing, the actual span was 12% less. best rate of climb for piston-engined Motorgliders do not have to meet the In flight test, the “advanced” airplane airplanes, three-fourths of the total same stall speed and maximum speed proved to be inferior overall to the stock drag of the airplane is induced drag. rules as ultralights. While they need to airplane with the exception of top speed These differences affect the span load- climb well with low power, they also at near sea level. Its rate of climb was ing that is best for the airplane. need to fly efficiently at higher speed worse, and its cruise performance at any For low-powered airplanes that and have good enough L/D and sink rate realistic cruise altitude was not much fly relatively slowly, the need to get to soar with the motor off. better. The reduction in span canceled acceptable climb performance tends to Accordingly, motorgliders will have out any improvements provided by the drive the preferred design toward large higher wing loadings and higher aspect advanced technology and reduced wet- span. Motorgliders and ultralights have ratios than ultralights. The higher wing ted area. (See “Flight Test Results for an large spans for their weight in order loading tends to make the wing smaller, Advanced Technology Light Airplane,” to be able to climb well with relatively so the aspect ratio must increase to David L. Kohlman: Journal of Aircraft, small engines. keep the induced drag down to an Vol. 16, No 4: April 1979.) It’s interesting to note the difference acceptable level. The importance of induced drag varies between these two types as well as the Higher-powered airplanes that are over the flight envelope. similarity. Part 103 ultralights are limited intended to cruise quickly cross-county • When the airplane is flying at its best to a level-flight maximum speed of 55 generally have higher wing loadings lift-to-drag ratio (L/D), half of the knots and a stall speed of not greater than slower-flying machines. This tends total drag is induced drag. than 24 knots. This makes parasite drag to make the wing smaller both in area • At airspeeds faster than the speed relatively unimportant and places a pre- and span. We can compensate for the for best L/D, the parasite drag is mium on low wing loading. Ultralight span decrease somewhat by increasing larger than the induced drag. wings are large, but have aspect ratios aspect ratio, but the smaller the wing • At airspeeds lower than that for best similar to heavier light airplanes. They area, the more structurally challenging L/D, induced drag is larger than par- get their low span loading from a com- (and heavier) the wing gets. Fortunately, asite drag. bination of light overall weight and the the higher power needed for fast cruise

76 KITPLANES July 2020 www.kitplanes.com & www.facebook.com/kitplanes where the majority of the drag is para- be able to operate two side-by side cat- Sometimes, the need for extra span site drag also gives the airplane more apults simultaneously. to meet performance requirements is so excess power to overcome induced Span issues can also be a problem for large that designers must take extraordi- drag in climb. large transports. One of the reasons the nary measures to get the needed span High-altitude cruise tends to favor A-380 did not become more popular is and still be able to operate out of exist- lower wing loadings and longer spans. that it did not fit into the taxiway and gate ing bases. Boeing recently flew a new There have been several cases in recent requirements of most airports. While a few version of the 777 (777X) that has fold- memory where wingtip extensions on major hub airports were willing to build spe- ing wingtips. These tips fold up on the fast single-engine airplanes actually cial infrastructure to support the airplane, ground like the wings of a carrier-based improved their cruise speed at altitude many other airport operators were not, and Navy airplane to enable the airplane to because the reduction in induced drag the A-380 is thus constrained to serving a use existing gates, but have enough span caused by the increase in span was larger relatively small number of airports. to fly long range efficiently.J than the increase in parasite drag caused by the increase in wetted area. The most common example of this is the Glasair line of airplanes that are offered with a standard wing and optional wingtip extensions that double as extra fuel tanks.

Weight Trade Once wing loading has been determined (usually from stall speed or takeoff and landing considerations), the choice of aspect ratio becomes a tradeoff of structural weight against induced drag. Increasing aspect ratio increases span (at constant wing area) but also makes the structure of the wing heavier. The increased structure weight exacts a performance penalty. For each airplane there is a point where the cost (either in material or performance) of increasing aspect ratio and span further outweighs the reduction in induced drag. As we have discussed above, this optimum point varies dramatically depending on the mission and configuration of the airplane.

Non-Aero Considerations Sometimes the span of the airplane is constrained, not by aerodynamic or performance considerations, but by ground infrastructure. For light airplanes the designer should take into consideration that a lot of standard T-hangars are 38 feet wide. Increasing span beyond about 37 feet may improve performance, but it will also make the airplane more expensive to hangar. U.S. Air Force fighter designs are constrained in span by the width of the standard hardened shelter on U.S. Air Force bases, and carrier-based Navy airplanes have span constraints imposed by the size of the ship and the need to

KITPLANES July 2020 77 REAR COCKPIT Missing Red Bull Am I alone when saying the Red Bull Air Races were not my ideal of aviation pursuit? I surprise myself a little saying that, as racing in many forms has held my interest—and pocketbook—for decades. And let’s face it, almost anything to do with airplanes is high interest in this house- hold, so why throw FOD at Red Bull? Well, I wasn’t really throwing FOD; I was simply saying the RB air races weren’t “ideal.” And to a purist racer (a quaintly extinct concept where money is involved) that’s fair criticism. This is because, like much of professional racing where there is always outstanding effort and skill at play, to the spectator the emphasis around all those puffy pylons was show- manship. From takeoff to landing the RB races were carefully controlled by Red Bull—as is their right as they were paying the bills—and much of the excitement in watching a handful of pilots taking turns Mass entertainment and selling energy drinks is what Red Bull was after with their air races, jousting with the stopwatch was given but incidentally they concentrated money and thus talent in the service of Experimental aviation. (Photo: Cp9asngf/CC BY-SA [https://creativecommons.org/licenses/by-sa/3.0]) to us by a breathless Red Bull announcer and a bevy of properly stern Red Bull offi- engine sourced from Lycoming’s Thun- in the sky. Of course this is something of cials clearing pilots on and off the course, derbolt shop. That took the impetus out a sophist truism as it takes money to get commanding smoke on and so forth. of engine development, so innovation just about anything material done, but Count me more of a wing-to-wing concentrated on tweaking the aerody- it’s worth noting concentrations of social pylon racing fan, as practiced in Nevada namics and especially in determining lubricant are a necessity, not a nicety, each September. The greater freedom of the ultimate flight path and learning when putting together exceptional fly- experimentation at Reno, along with the how to fly it. Even then Red Bull didn’t ing machines and pilots. In short, it takes emphasis on outright speed and han- need the wings coming off on global rich people, companies or even nations dling rather than the absolute perfec- television, so only limited airframe hot- to make things happen. tion in flying the optimum line in a time rodding was allowed. History backs this up: When reviewing trial appeals to me. Red Bull started with But now the Red Bull Air Races are the big jumps aviation has made, it’s clear a bit of technical freedom, especially in extinct and I’m missing them. Not for the the first, immense, pioneering work was engines, as this was likely necessary to show or canned drama, but for concen- mainly the sacrifice of purposeful individ- build the framework of the show. But trating money into an aviation discipline uals and that it took two rather talented after a few seasons costs were going up and the resulting progress and marketing and dedicated self-taught engineers with as competitors chased ever diminish- of aviation that ensued. For, if anything, hired help and all the money they could ing speed returns—the only way rac- we’ve all noticed it takes money to fly, make with their thriving bicycle shop ing goes—and Red Bull went to a spec and even more money to make progress to make that first viable airplane. Even

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 July 2020 www.kitplanes.com & www.facebook.com/kitplanes then their goal was to sell it to the U.S. we’ll feature in an upcoming issue, and as their engines were run in competi- government, right after they patented it. the same can be said for Roger Targett. tion much more often. Plus, the volume But soon it was the First World War driv- Another Reno air racer with Red Bull back- of premium engines going through the ing aviation design, meaning govern- ground is F1 winner Vito Wyprächtiger, shop gave them a much wider base to ment money, followed by the Depression who was a Red Bull test pilot. spread out R&D costs or even opportu- when air racing in all its forms is where The point is, all of these people have nities to try something new. aviation progress was largely made in contributed to sport aviation and have It isn’t quite the same for Thunderbolt. pursuit of prize money (not to discount also found paychecks thanks to Red Bull. Where Ly-Con had to compete by offering the formation of reliable commercial Not only has that kept them making more power while maintaining endur- air travel during the same period). Of a living in aviation, but also they were ance, Thunderbolt simply has to build the course, this golden age was followed by brought together to work on the same, or same spec engine again and again. There the incomprehensibly frenzied activity at least similar, problems within the Red are some R&D benefits to that, but mainly of WW-II, an event that ushered in the Bull rules. They all know each other, and in build consistency and manufacturing Big Money era of government, science, their shared experience is a great starting practices, not power or endurance. engineering and so on working together point should they want to collaborate on Of course the other great benefit of on atomic bomb and moonshot scales. future aviation improvements. the Red Bull Air Races was the exposure Since then, big gains in flight have been Besides the individuals graduating of aviation as a fun, exciting enterprise to mainly unobtainable by the individual from Camp Red Bull, there are shops and the non-flying public. With its staggering and thus became the purview of gov- manufacturers. Perhaps the best exam- televised audience we’ll never know how ernments and the inexorable demands ple of direct technology transfer in a many people were favorably impressed of the global commercial air biz. As business sense is Ly-Con Aircraft Engines. by small airplanes thanks to Red Bull, but a result, fighting aircraft are outpac- Before Red Bull went to Thunderbolt, it couldn’t have hurt. ing human capacity, airliners continue Ly-Con was sponsoring or supplying In the end the good from Red Bull was a grand march on fuel efficiency and engines to as many as eight Red Bull due to their immense marketing budget general aviation soldiers on with a mix teams. Already well versed in Reno rac- that put up the purses, bought the televi- of oxcart technologies and a few bright ing, Ly-Con certainly upped their expo- sion time, ran the circus around the globe spots when the accountants dare or mili- sure and experience via the RB series. The and even if only incidentally formed a tary, commercial and sport requirements busy Red Bull schedule meant their cli- place for the eager and talented to con- overlap, such as in GPS navigation. ents were racing six, eight or more times gregate. It might have been a little showier The point is, aviation progress has per year, not just once as at Reno, thus than an old purist might have preferred, largely been determined by well-defined, rapidly accelerating Ly-Con’s knowledge but the benefits have been great.J rewarding goals, which concentrated talent and resources. Nothing over- whelmingly unusual about this, but in an otherwise fairly vacant space, the Red Bull Air Races provided well-defined goals, rewards and definitely attracted talent. Unairworthy No more proof of the talent concentrated is required than reviewing a very partial list of gifted amateurs or small- business people who until recently found work in RB air racing teams. More than a few of these names are familiar to most of us, such as Craig Catto, the propeller meister, or Andy Chiavetta, all-around fab- ricator and technician with a solid history of making all sorts of fast airplanes faster, especially Sport Class Reno contend- ers. Another name not needing much Jam Nut Triple Threat introduction is Paulo Iscold, who started Jam nuts serve a purpose and that is to prevent actuating arms from becoming by building his own record aircraft in his disconnected. I found three examples on the same airplane. Two flap jam nuts native Brazil but has moved to the States were loose and should have been caught on a preflight, and the autopilot servo and is now working with Catto. In Eng- arm jam nut was loose as well. Any of these could cause a flight control problem if land Rob Martin has taken his fabrication they came completely loose. J skills from Red Bull to a new record aircraft —Vic Syracuse

KITPLANES July 2020 79 ARCHIVE January 1988 Jim Bede’s BD-5 had, by the late 1980s, still managed to hang onto its Bond-esque glory despite never really finding a good piston powerplant to fit into the airplane’s thin midsection. The Hirth two-stroke was among the most common engines in the BD-5’s pre-jet gestation, but it could be temperamental. A popular engine at the time was a conversion of a Honda all-aluminum inline-four. For our January 1988 issue, Don Downie reported on one engine that performed well and had no cooling issues. Bob Sauser’s BD-5Vee, as he called it, used a developed version of the VW flat-four. Sauser spent many hours developing a cooling system fed by side-mounted NACA ducts and augmented by electric fans for ground cooling. Experimentation with a purpose! Inside the issue, editor Dave Martin reported on Rand Robinson’s single-seat KR100, a Continental O-200-powered single-seater with 200-mph cruise on just 66 square feet of wing. The kits were due to be available later in 1988 but the airplane was never actually offered. On that same spread was an ad for the ill-fated Prescott Pusher; the stubby four-seater promised 200 mph cruise and “turbocharged and liquid-cooled engines.” The kit debuted to much fanfare but the company folded before it could produce many kits. Some 16 Prescott Pushers are currently on the FAA register but it’s unclear how many are actually flying. Ken Armstrong reported on Murphy’s Renegade Spirit biplane, powered by a Rotax 532. “Addition of the 532 engine and the large-diameter propeller had increased the speed considerably,” he said. “We awed the designer when we told him we were getting a consistent indicated airspeed of 95 mph (true airspeed 100 mph)! Now that’s fast for a biplane with only 64 hp.” At the back, we had 13 pages of classified ads. Life before the internet.J

Details on the BD-5Vee’s engine installation appeared in this issue (above) as well as an ad for the Prescott Pusher (left). Choose an inflight video in VHS or Beta!

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