Titan T-51 Mustang

ADS-B Update: What You Need to Know KITPLANES

AUGUST

2017

® Titan T-51 • ADS-B • Engine Horsepower! Failure • Transition Training • Vortex Generators • Electrical Systems • Tube Bending • Cooling Fans • Scale Titan T-51 Model

Testing Mustang

Engine Failure

BELVOIR Are You Prepared? AUGUST 2017

Transition Training In the Shop: PUBLICATIONS Moving to Experimentals • Cooling Fans • Tube Bending Vortex Generators • Make Your Own Antenna

Do They Really Work? www.kitplanes.com Clear, Vibrant Displays Meet SkyView HDX - the new Beautiful Design flagship from the market leaders in Unrivaled Control Ergonomics experimental and light sport avionics. Improved Touch Interface Capable and Compatible

DynonAvionics.com [email protected] (425) 402-0433 August 2017 | Volume 34, Number 8 Flight Review 6 Marvelous Mustangs: Titan adds new engines and a B-style fuselage option to the T-51. By Patrick Panzera.

Builder Spotlight 18 What is happening on the ADS-B Scene? A quick review as we move closer to the 2020 deadline. By Dick Sunderland. 24 What’s a Nice Guy Like You Doing in a Plane Like This? Making the transition from certified aircraft to Experimentals. By Todd DeVito. 18 32 sizing an Avionics Cooling Fan: How much is enough? By Norm Ellis. 38 vortex Generators on an RV-8: Do they really make a difference? By Nigel Speedy. 48 engine Failure! Are you prepared? By LeRoy Cook. 52 r apid Prototyping and Experimental Design: Scale model structural testing. By Eric Stewart. 66 a sk the DAR: Increasing gross weight, adding IFR to operating limitations, transponder requirements. By Mel Asberry.

Shop Talk 47 the Creative Homebuilder: Simple tools for setting smooth pop rivets. By KITPLANES® Staff. 56 Home Shop Machinist: Tube bender Model 3. By Bob Hadley. 60 Best Practices: Electrical, part 2. By Dave Prizio. 72 Aero ’Lectrics: Verticality. By Jim Weir.

Designer’s Notebook 75 Wind Tunnel: Gyroplanes, part 3. By Barnaby Wainfan.

Exploring 2 Editor’s Log: Failure of imagination. By Paul Dye. 6 64 Checkpoints: Fun in cold weather. By Vic Syracuse. 78 rear Cockpit: The most necessary thing in aviation. By Tom Wilson.

Kit Bits 4 Letters 67 list of Advertisers 68 Builders’ Marketplace 80 kit StufF: Drawing on experience. By cartoonist Robrucha.

On the cover: John Williams flies Titan Aircraft’s “razorback” T-51B near Lakeland, 24 Florida. Photographed by Sheldon Heatherington. Photo Pilot: Michael Turner. For subscription information, contact KITPLANES® at 800/622-1065 or visit www.kitplanes.com/cs. KITPLANES August 2017 1 Editor’s log Failure of imagination. When the dust settled on the inves- about that. Flying itself is dangerous on because no one had ever thought about tigation of the Space Shuttle Columbia the face of it, but we mitigate the hazards them in advance. accident, the new program manager, with good design, certification, training, The biggest fears of most pilots— former Flight Director Wayne Hale, was practice, and the use of good judgment. loss of flight control, structural failure, asked by the press to simply state what When we get into the Experimental air- or fire—can all be dealt with by good failure caused the accident. Hale, a craft world, the certification part of each design and good practices in con- thoughtful, well-educated man paused design is taken away from the risk man- struction and maintenance. We know and answered with a phrase that was agement equation. We might use a certi- to design structure to much higher previously used to describe the cause fied engine, and a good designer might loads than we expect to see in flight, of the Apollo 1 fire back in 1967. “It was very well use the certification standards and we can build and inspect to make a failure of imagination,” he said. “We as their personal design criteria (many sure that the structure we fly is free just never imagined that a piece of do), but there are all sorts of little things of cracks and defects. Fire risk can be lightweight foam could knock a hole that can bring a flight to ruin—and many mitigated by using proven materials in the reinforced carbon-carbon lead- of them surprise us when they happen and assembly techniques for fuel and ing edge of the wing.” No one had ever questioned the strength of the leading edge, and therein lies the basic problem with predictive failure analysis— dealing with things that you simply didn’t think of. Good risk management relies on the imagination. You have to think up all of the things that could possibly go wrong with a machine or an operation, and then once you have that list, you sit down and come up with ways to mitigate each of the risks. Some you can prevent with a redesign. Some you can make less critical by adding redundancy. Others you simply end up accepting; hopefully they are extremely low probability. But all of those efforts fail to keep you safer if you have unimagined or unidentified risks. And the truth is, they are always going to be out there. Building and flying our own airplanes NASA flight controllers spend countless hours analyzing systems drawings for potential is a risky endeavor—there is no doubt failures. And they still miss those they can’t imagine.

Paul Dye, Kitplanes® Editor in Chief, retired as a Lead Flight Director for NASA’s Human Space Flight program, with 40 years of aerospace experience on everything from Cubs to the space shuttle. An avid homebuilder, he began flying and working on airplanes as a teen, and has experience with a wide range of construction techniques and materials. He flies an RV-8 that he built in 2005, and an RV-3 that he built with his pilot wife, as well as a Dream Tundra they recently completed. Currently, they are building a Xenos motorglider. A Paul Dye commercially licensed pilot, he has logged over 5000 hours in many different types of aircraft and is an EAA Tech Counselor and Flight Advisor, and a member of the Homebuilder’s Council. He consults and collaborates in aerospace operations and flight-testing projects across the country.

2 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes other combustible lines and containers, crimp or a corroded connection in a wire. a moving flight control surface and a as well as doing the same thing for elec- Installing wiring in an aircraft seems like fixed portion of structure—leading to a trical systems. Loss of control can be a small part of the overall build—espe- jammed or sticky control. That’s going caused by poor aerodynamic design, cially when you have something that to have a really bad result if it happens in control system failure, or failure on the looks like an airplane—but these small flight. So, is that perfectly straight, small- part of the pilot to maintain skills or and seemingly trivial installations can clearance gap that you hoped to give properly load the aircraft. lead to all sorts of problems. you an extra knot really worth it? Again, All of these “big three” fears can be More and more Experimental aircraft imagine what can happen, and don’t be mitigated if the pilot wears a parachute are flying with electronic ignition sys- afraid to think outside the proverbial box. and has the capability to bail out—but tems, many of which are dependent In fact, the only way to free our imagina- most of us don’t fly around with para- upon ship’s power to operate. Older tions is to open that box. chutes all the time, so we design and aircraft engines with magnetos will There are no trivial decisions when build so that these risks are very tiny. keep running so long as the P-lead is it comes to building an Experimental But those are things we have thought ungrounded and the engine has com- aircraft, and every one of those deci- about; how about all of the things that pression and fuel. But those electronic sions needs to be looked at with a we haven’t? Mishap reports that can be ignitions that don’t generate their own healthy dose of imagination to think traced back to design or build errors are power depend on good electrical wir- about what might go wrong. No one’s often unique—and once determined, ing to keep them in the air. Yeah, it can imagination is boundless, so don’t be we sit back and say, “Wow…I’d never be really tough to reach into the nest of afraid to ask others for their opinions thought of that before.” It’s a failure of wiring behind the engine or under the on a change; you might not agree with imagination, right there. panel to make those last few crimps, but their conclusions, but if they can come One way to have a bigger imagina- imagine the case where those crimps up with a scenario you haven’t thought tion is to study the history of accidents come undone. of, it’s a win. Imagine what can happen due to design and construction failures. I have also seen places where ther- when we all work together in Experi- I cannot tell you how many times I have mal expansion or deformation due to air mental aviation to make our planes— traced systems failures back to a bad loads has caused interference between and operations—safer. J

Photo: Paul Dye KITPLANES August 2017 3 EDITORIAL Editor in Chief paul Dye [email protected] In Memoriam—Geoff Jones “fall into lockstep,” deepening and Executive Editor mark Schrimmer Sadly, the KITPLANES® editorial staff evening out the threads. The tool deter- Art Direction Dan Maher was informed that Geoff Jones, a long- mined the thread spacing, one-eighth Editorial Director paul Bertorelli time contributor to our magazine, passed inch or whatever, and its mass would Contributing Editors larry Anglisano, Marc Ausman, away at his home in Wales in April, just as help even out the threads and prevent leRoy Cook, Robert Hadley, Dan Horton, Louise Hose, this issue was being prepared. Geoff was a wobble. It’s easy to see where the term amy Laboda, Dave Martin, freelance aviation journalist and photog- “chasing” came from since the wood- sid Mayeux, David Paule, Dave Prizio, Ken Scott, rapher for over 40 years and earned his worker or metalworker had to chase elliot Seguin, Dick Starks, Private Pilot license in 1977. the threads down the workpiece. This eric Stewart, Vic Syracuse, barnaby Wainfan, Jim Weir, For this month’s report on Titan Air- YouTube video, at its center, demon- tom Wilson. craft’s T-51 Mustangs, Geoff visited Ben strates the practice: http://tinyurl.com/ Web Editor Omar Filipovic Chester-Master, the U.K. and Euro- ma76asc. Over the years, the term has Cartoonist Robrucha pean agent for Titan, who explained expanded to include cleaning up dam- ADVERTISING the differences between his Suzuki- and aged or corroded threads using a die or Sr. Advertising Manager Chuck Preston Honda-powered Titan T-51s. threading lathe. 805/382-3363 In addition to KITPLANES®, Geoff’s Gary Gordon [email protected] work has appeared in many other avia- BUSINESS OFFICE tion magazines in the U.K., Germany, Ignition Advance Belvoir Media Group, LLC 535 Connecticut Avenue Italy, the U.S., and South Africa. He I enjoyed Nigel Speedy’s article, “The Norwalk, CT 06854-1713 was also the author of numerous books Effects of Ignition Advance on Cyl- EDITORIAL OFFICE including The Big Six U.S. Airlines, inder Head Temperature, Speed, and 535 Connecticut Avenue American Classics of the Air, and Vin- Efficiency,” [May 2017]. The testing and Norwalk, CT 06854-1713 tage Aircraft over America. article reinforces what our research and [email protected] Tailwinds, Geoff. We’ll miss you. testing has shown since we have been in CIRCULATION business. These kinds of results are the Circulation Manager Laura McMann Thread Chasing exact reason we set our ignition systems SUBSCRIPTION DEPARTMENT Years ago, one of my treats was seeing up the way we do. Again, a well-written 800/622-1065 KITPLANES® arrive in the mailbox. article describing in easy-to-understand www.kitplanes.com/cs After a long hiatus, I decided to re-sub- terms the effect of a good ignition sys- P.O. Box 8535, Big Sandy, TX 75755-8535 For Canada: PO Box 328, Norwich, Ontario N0J 1P0 scribe, and I’m delighted to see that it’s tem on engine performance. still the same wonderful magazine. Michael Kobylik REPRINTS FOR PUBLICATION ElectroaiR AND WEB POSTING AVAILABLE Reading Bob Hadley’s excellent arti- Minimum Order: 500 cle, “Chasing the Elusive Thread” [May Contact Jennifer Jimolka, 203/857-3144 2017], I concluded I must be much older. Help for More Than Aircraft The term “thread chasing” originally I subscribe to quite a few “do-it-your- referred to the method where the first self” type magazines such as Hot Rod, Change of address? threads in England were cut freehand, Popular Mechanics, etc. Of all of them, Missing issue? using neither a die nor a threading lathe. yours is by far my favorite. A lot of what Subscription Question? The craftsman hand guided a tool along I learn is applicable to my other hobbies Visit www.kitplanes.com/cs. the workpiece at the rate he thought as well as to aircraft. Please keep up the Or call 800/622-1065 from the U.S. and Canada. would have the threads overlap. (I think good work. they practiced with a pencil). Once the Ken Williams Foreign 903/636-1112 or fax threads started to form, the tool would 203/857-3100. We’re always happy to help!—Ed. J

Website Information: General homebuilt aircraft information, back issue availability, online directories ordering info, plus a Kitplanes® article index and selected articles can be found at www.kitplanes.com. Unsolicited manuscripts: are welcome on an exclusive basis, but none can be acknowledged or returned unless accompanied by a stamped, self-addressed envelope. No responsibility is assumed for loss or damage to unsolicited material. Kitplanes® (ISSN 0891-1851) is published monthly by Aviation Publishing Group, LLC, an affiliate of Belvoir Publications, 535 Connecticut Avenue, Norwalk, CT 06854-1713, Robert Englander, Chairman and CEO; Timothy H. Cole, Exec. Vice Pres./ Editorial Director; Philip L. Penny, COO; Greg King, Exec. Vice Pres./Marketing Dir.; Ron Goldberg, CFO; Tom Canfield, Vice Pres., Circulation. Periodicals postage paid at Norwalk, CT, and at additional mailing offices. Copyright ©2017 Aviation Publishing Group, LLC. All rights reserved. Reproduction in whole or in part is strictly prohibited. Printed in USA. Revenue Canada GST Account #128044658. Canada Publishing Agreement #40016479. Subscriptions: One year (12 issues) is $29.95 U.S. $41.95 in U.S. funds in Canada, includes GST. $41.95 in U.S. funds for Foreign Surface Mail or $57.95 in U.S. funds for Foreign Air Mail. Single copy price $4.99 U.S., $5.99 Canadian. POSTMASTER: Please send address changes and subscription inquiries to: Kitplanes®, P.O. Box 8535, Big Sandy, TX 75755-8535, or Canada Post: Return undeliverables to P.O. Box 2601, 6915 Dixie Rd, Mississauga, ON L4T 0A9 or call 800/622-1065. Kitplanes® is a registered trademark of Aviation Publishing Group, LLC.

4 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes

Marvelous Mustangs

Titan adds new engines and a B-style fuselage option to the T-51. By Patrick Panzera

6 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Marvelous Mustangs

Photos: Patrick Panzera and Paul Dye. Air-to-Air Photos: Sheldon Heatherington. Photo Pilot: Michael Turner. KITPLANES August 2017 7 Bill Koleno is a master machinist, metal fabricator, and capable pilot who enjoys research and development and who ful- fills all three of these roles while working at Titan Aircraft. At the tender age of 9, Bill considered himself a machinist, and by the age of 17 had built a gyrocopter in which he taught himself to fly. As an adult, he opened a machine shop where he fabricated parts and tooling for his customers who currently include General Motors, Chrysler, and Toyota, among others. In 2006 he joined the Titan team (while also keeping his shop Bill Koleno and the V-8 powered T-51D, Camel Smoker. running) and is currently working on the creation of a full-size P-51 replica Bill serendipitously met John by mov- logging about 1200 rotary-wing flight to go alongside Titan’s popular T-51, a ing across the street from him in 2002. hours, he moved on to fixed-wing air- three-quarter-scale, all-aluminum P-51 While house hunting, Bill’s wife liked craft, starting with a Grumman Yankee. Mustang available as a kit. The T-51 can the house down the road from John. John Williams also started early, get- be built as either a high-powered Experi- Bill really didn’t care for the house, but ting his Private Pilot license at age 16. mental with retractable gear, or with he noticed that the “guy across the way” He flew certified aircraft for a long time fixed gear and a smaller engine, it fits into had a runway—so he decided he liked it before coming across the CGS Hawk, an the Light Sport Aircraft (LSA) category. after all. He then fixed it up the way he ultralight-like Experimental sport plane John Williams is the mover and wanted it and met John as he was mov- that he really enjoyed flying. Seeing that shaker of Titan Aircraft Company, ing in. One of their neighbors asked Bill CGS needed help with production, John which is located in Austinburg, Ohio, why he was building a barn, and when joined the team in the 1980s and whet his in the northeast corner of the state. The he told him it was so he could build a appetite for building and designing light factory is a large, upscale facility hous- couple of airplanes, the neighbor said, aircraft. No sooner did he get comforting John’s electronic controls business, “You’ve got to meet John.” able with the process then he designed along with the offices and production Bill’s gyrocopter infatuation was not his Titan Tornado, an ultralight that floor for the aircraft business. Titan is short lived. Without plans and work- has a full aluminum cantilevered wing, best known for the light and ultralight ing only from photos, he copied Ken steel-tube cockpit, and manages to fit kit aircraft that have been in production Brock’s early designs and powered his into the very restrictive Part 103 ultra- for over 20 years. with a direct-drive Subaru engine. After light category. This plane was the first of 13 similar Tornado designs, including several two-place tandem Experimental versions. Currently, there are only four models being offered by Titan, with either 24- or 26-foot wingspans. All are Sport Pilot qualified, and all are offered with a float option. The Titan T-51 John always wanted a North American P-51D Mustang. In fact, there was a P-51 located at the field where John worked with CGS. But the going rate for a Mus- tang was way out of his price range, and the price has only grown exponentially with time. Realizing that he would probably never be able to afford areal Mustang, the decision was made to build a scaled version of his own. The issue was finding a reliable (and affordable) Titan T-51D (foreground) and North American P-51D. Any similarity is purely intentional. engine from which to design the aircraft

8 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes

Titan Aircraft T-51D

Kit Price ...... $54,900 Estimated completed price . . . . Less than $100,000 Estimated build time ...... 1600 hrs Powerplant . . Chevrolet V-8 LM4, 290 hp @ 4000 rpm Propeller ...... Whirl Wind, constant-speed Powerplant options . . GM V-8, Honda V-6, Suzuki V-6, ...... Rotax 912/914

AIRFRAME Wingspan ...... 24 ft 0 in Wing area ...... 118 sq ft Wing loading ...... 18.65 lb/sq ft Fuel capacity ...... 26 gal Maximum gross weight ...... 2200 lb Typical empty weight ...... 1350 lb Typical useful load ...... 850 lb Titan T-51 Camel Smoker on display across from the Titan booth at EAA AirVenture 2016. Full-fuel payload ...... 694 lb Seating capacity ...... 2 the present, and John says that the 100- four-cylinder turbocharged Suzuki Cabin width ...... 26 in hp four-stroke Rotax 912 S is as reliable engine that didn’t work, mostly due to as a Lycoming or Continental. the power-to-weight ratio being infe- PERFORMANCE Back when engine decisions were rior to the 912. But then he moved up Cruise speed ...... 190 mph Maximum rate of climb ...... 3000 fpm being made for the T-51, Rotax stated to a Suzuki 2.5-liter V-6 with a belted Stall speed ...... 42–52 mph they were working on a six-cylinder ver- propeller speed reduction unit (PSRU) Takeoff distance ...... 400 ft sion that John was somewhat banking weighing in at 317 pounds and making Landing distance ...... 400 ft on upgrading to once it was well proven. about 160 hp. News of this installation But that never came to be. John wasn’t a made the circuit, and not long after, around. Being a Rotax engine distribu- fan of automobile conversions either, so John’s customers started asking about it tor through Titan, it seemed natural that left him with few options; the time- for their planes. to try using the 65-hp Rotax 582, but proven horizontally-opposed certified Still not willing to trust a one-off being two-stroke, reliability was a con- engines just wouldn’t fit in the cowl. design, he asked the builder to let him cern. When Rotax came out with their To further drive home the anti-auto- know when he hit the 300-hour mark. four-stroke 912 engine, John was still engine-conversion attitude, one of Once notified, John hopped on an air- apprehensive, but Rotax gave him an John’s Canadian T-51 customers was liner to Calgary to fly that plane, full engine to test on his two-place Tornado unsuccessfully experimenting with dif- of preconceived notions that he’d hate that changed his mind. Fast forward to ferent engines, starting with an inline it (just so he could objectively tell his

V-12 Rolls-Royce (BMW) powered Titan T-51B before paint.

10 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes hours after that, and include a thorough inspection with a borescope. The PSRU is gear-driven and lubricated by splash from its own source, not engine oil, so oil analysis can spot trouble before it gets too far. The New V-8 Since the LM4 is no longer available as a long-block crate engine, the more powerful, 6.2-liter Chevy LS3 ($7,911 MSRP) will be the engine of choice for those wanting V-8 power in their T-51. The crate version of the 430-hp LS3 engine (restricted to 300 hp at 4000 rpm for the The 6.2-liter Chevy LS3 V-8 is the engine of choice for those wanting V-8 power in their T-51. Titan T-51) is standard in the Chevrolet Corvette, Camaro, and the ill-fated SS, customers that he knew firsthand that so they moved on to the New Zealand- and comes complete from GM—from it was no good). But he found out oth- made Autoflight geared PSRU. Engi- the oil pan to the ignition system. It erwise once in the cockpit and behind neered for 300 horsepower with a 1.5 also includes the composite EFI intake the controls. According to John, “It did safety factor, it also allows the use of a manifold assembly with injectors, fuel everything better; it doubled the climb constant-speed propeller. John tried rail (returnless, multiport fuel injection) rate, and it didn’t adversely affect the a Honda V-6 as an upgrade from the and throttle body, nodular steel exhaust stall speed.” Suzuki, but ultimately he landed on a manifolds, aluminum high-volume A Suzuki V-6 powered Titan T-51 Chevrolet V-8. water pump, harmonic balancer, and a with a fixed-pitch propeller and fixed With the Autoflight PSRU, John says high-resolution 58x crank position sen- landing gear will meet the LSA mini- there were “zero teething pains and zero sor directing the high-energy solid-state mums in a single-place configuration, trouble” with the General Motors LM4 direct-fire distributorless integrated with a full-throttle speed of 145 mph V-8 engine in the Titan T-51. The LM4 ignition system with “coil near plug” (not maximum continuous power— is the aluminum version of the LM7 architecture. It’s a very complete and that’s limited to 138 mph for LSA) and that makes the same 290 hp but weighs compact package. a full-power climb of 2000 fpm. 80 pounds less than its iron-blocked The LS3 is filled with components Back at the shop, John made the deci- twin. With most auto conversions, the and features designed for high per- sion to install a copy of the Suzuki V-6 engine itself is usually bulletproof— formance and longevity, including in an airframe they were prepping to it’s the systems and/or the PSRU that a 90-degree-cylinder-angle cast-alu- receive an Innodyn turbine. He gave the tend to fail. So with that, John and Bill minum block, forged crank (manual engine the moniker “Mini Merlin,” but elected to change the oil in the PSRU at transmission version), forged rods, and the belt drive proved to be problematic, 5 hours, then 10, then 20, and every 50 hypereutectic aluminum pistons. The

The rear seat has full flight controls, including throttle. The canopy is closed with a crank—just like the full-sized P-51.

KITPLANES August 2017 11 ONE OF THE FEW KIT PLANES WE DON’T INSURE.

Even with a Dynon EFIS, Garmin avionics, and a few other modern The throttle quadrant in the T-51 duplicates the look and feel of the instruments, the cockpit retains the look of a WW-II fighter. one in the original P-51.

L92-type rectangular-port heads are over previous engines by straightening to go flying in the latest iteration of cc’d for 10.7:1 compression ratio, and the out and optimizing the flow path from the T-51. So far, I’ve had the pleasure hollow, high-lift hydraulic roller cam- the intake manifold into the cylinder to fly in the 100-hp Rotax 912 ULS shaft still uses traditional pushrods to heads, while the exhaust ports are also version and both of the V-6 powered actuate the roller rockers. The all-alumi- designed for greater flow. An engine is planes more than once, but during the num oil pan houses the dry-sump lubri- just an air pump. The more efficiently it 2016 show, I got to fly the V-8 powered cation system that uses 8.9 quarts of oil. can pump air, the easier it can convert T-51D. And at Oshkosh later that year, All this adds up to be a lightweight, air/fuel into power. I flew the Rolls-Royce (BMW) V-12 well-engineered, reliable powerplant. Titan T-51B prototype. The LS3 6.2L engine delivers a great Flying the Titan T-51D While I’m qualified and potentially balance of performance and efficiency. Each year at Sun ’n Fun in Lakeland, skilled enough to fly solo from the front In fact, the 2010 Corvette gets up to Florida, I typically begin my day in the seat, I felt far more comfortable with 26 mpg on the highway with the man- ultralight area, commonly referred to Bill in the front seat and PIC. Paradise ual transmission. But the engine can’t as “Paradise City” and named for the City is a busy little uncontrolled grass take all the credit; the body has been 1989 Guns N’ Roses anthem of the strip with mosquito-like ultralights reworked to reduce drag. Another key same name. One of my regular visits buzzing around with as many as 15–20 to the LS3’s efficiency is great airflow is with the people of Titan Aircraft, in the pattern at any given time. While throughout. Intake flow was improved which usually ends with an invitation they do keep the powered parachutes

We now insure more homebuilts. Talk to us. (888) 241 7890 Avemco.com Avemco Insurance Company is a member of the Tokio Marine HCC group of companies. ADS0158 (12/16)

12 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Avemco Insurance Company is a member of the Tokio Marine HCC group of companies. ADS0158 (12/16) ONE OF KITPLANES THE FEW We nowinsuremorehomebuilts. WE DON’T INSURE. WE DON’T Talk (888) to us. 2417890 Avemco.com and trikes separate from the more tradi- tionally configured (and faster) aircraft, a 200-mph high-performance plane like the T-51 just seems so out of place. Each morning there’s a pilot’s briefing where the traffic pattern and proper procedures are conveyed, and each attend- ing pilot leaves with a distinctively colored wristband for that day. In short, the faster planes fly a larger pattern than the slower ones do. There are also designated practice areas outside the pattern, and a predesignated pattern entry point. It’s all see and avoid, with no radio contact and certainly no control tower. The back seat of the T-51 is rather small, and the ergonomics, while not The view from the back seat of Camel Smoker. impossible, are a bit unusual. It’s like you’re sitting in a dinner table chair, In addition to being the fastest plane but coordination was all seat-of-the- with your feet placed where they would in the pattern by a factor of more than pants, with no view of the ball in sight. go if you were sitting properly, but now two (even when throttled back), the With the unusual rudder pedal con- shorten the legs by half but keep your T-51 leaps off the ground after using figuration and the need to use rudder in feet planted where they are—then place less than a third of the tiny 1400-foot turns (it’s not like an RV in that respect), rudder pedals flat on the floor under grass strip and transitions to a mostly I still found it rather intuitive to use the your feet. You operate the rudder by vertical attitude with a nearly authen- proper amount of rudder for each of the keeping your feet flat, and shuffling tic-sounding exhaust note. It’s some- procedures we underwent. them fore and aft. While unnatural at thing to see from the ground, but is This wasn’t a “proper” flight program first, it was easy to overcome and quickly way more than an E-ticket ride from with flight test cards, checklists, and became second nature. Keeping off the inside the cockpit! a predefined routine; it was more of a brakes while on the ground was a bit Bill’s a big guy and a bit hard to see familiarization flight for my benefit that concerning, but again, not impossible. around, so nearly all my flying was done was conducted by a very experienced A nice pre-landing checklist item is to without the aid of any instruments. and capable PIC. We went through the make sure the person in back isn’t inad- Engine rpm was easy to manage with usual procedures such as slow flight, vertently on the brakes. sound, as was speed for the most part, steep turns, and recognition stalls— none of which were anything but what one would expect from a very well- behaved airplane. We even put the plane into steep climbs to show off the excess power. With the engine speed limited to under 4000 revs (peak hp is 430 at 5900 rpm and peak torque is 424 pound-feet at 4600 rpm), the sound wasn’t over- whelming. In fact at pattern speeds, we didn’t even need the intercom. After about 30 minutes of exploring the performance and ability of this very well-mannered but exceedingly powerful airplane, we ended the free- flight portion of our excursion with a pair of traditional aileron rolls, one each way, the second one to unscrew my non-aerobatic inner ear. I say traditional as each time I’ve flown with Bill, this is what we did before heading The partially constructed T-51B prototype was on display at AirVenture 2013. back to the pattern.

14 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes (Left) While the V-12 is literally pulled from a BMW motorcar, the Titan team found it fitting to add Rolls-Royce decals to the valve covers. (Right) The engine does in fact have its radiator installed in the belly scoop—and there is a variable exit door, just like the full-sized P-51.

The pilot briefing in the morning offered the opportunity at AirVenture when we actually did it and I saw the before each day’s flying includes pro- 2016 to fly the Titan T-51B (razorback fuel flow for myself. cedures for high-speed passes, which version, like the P-51B) with a proto- Of course, this flight in the Rolls- the people on the ground love to see. type Rolls-Royce (BMW) 5.4L V-12 Royce-powered B model ended in the Therefore, with the look of an authen- engine—capable of 322 horsepower traditional aileron rolls, but this time tic North American P-51 Mustang, and but limited to 300 for the T-51. While it was over Lake Winnebago, not Lake- now with the sound that’s never been there was little detectable difference in land, Florida—big difference. closer to the 12-cylinder Rolls-Royce speed and overall performance between Titan plans to offer the Rolls engine Merlin 66 engine (the little Rotax never the V-8 and V-12, the sound was perfect, option along with the Chevy LS3. They stood a chance!), it was time to show and the uniqueness of the installation is can be found at AirVenture at the far the crowd what this plane came to Sun absolutely marvelous. end of the homebuilder’s row, up against ’n Fun to do—and we did so with the One incredible feature of this engine the taxiway that separates the warbirds smoke system on! and the way it’s set up and installed is from the homebuilts. That seems a fit- Once again in the very capable hands that the dual redundant fuel system, ting location for this beautiful scale rep- of PIC Bill Koleno, he slipped that intake system, and ignition systems lica—halfway between the warbirds and incredible machine in for a textbook- are set up so that one side (bank) or the homebuilts.

perfect short-field landing, touching the other can be completely shut off, Panzera Patrick down squarely on his aiming point (just turning the V-12 engine into a slant- Patrick shy of midfield) before coming to a full 6. Other than detecting a moderate Panzera is stop within the advertised 400-foot power loss at cruise that can be easily the editor of range. Without missing a beat, he slid recovered by adding in some throttle, CONTACT! the canopy back as he whipped the tail there doesn’t seem to be a downside to Magazine, a around for a 180-degree taxi back to setting this up as an economy cruise nonprofit publication the staging area. configuration. Switching from the left dedicated to supporting So now I’ve had a front row seat of bank to the right and back again every Experimental aviation, with the transformation of this little replica 30 minutes or so (maybe even more a focus on alternative fighter aircraft. I’ve watched it grow from frequently that that) helps keep the engines. Patrick also hosts an an eye-catching LSA to a fire-breathing, engine wear symmetrical. annual Alternative Engine very capable, high-performance com- The payoff is lower fuel consumption. fly-in, leaving him very little plex aircraft, and by far one of the finest It burns less fuel with only six cylinders time to work on building his scale replica fighters currently available firing, even though more throttle has Corvair-powered Dragonfly. to the kit aircraft market. to be used to produce the same power For more on the alternative- (thrust) as with all 12 cylinders fir- engine gathering, please visit Rolls-Royce V-12 in a T-51B ing, and it still remains silky smooth. www.contactmagazine.com/ A few months after flying the V-8 pow- I was surprised when Bill told me we’d roundup.html. ered Titan T-51D at Sun ’n Fun, I was be doing this, and even more amazed

KITPLANES August 2017 15 Honda vs. Suzuki in the T-51 The U.K. and European agent for Titan Aircraft’s T-51 Mustang is Moccas Mustang, founded by 54-year-old Ben Chester-Master. Ben’s dealership is named after his previous home at Moccas Court on the banks of the River Wye in Herefordshire, U.K. He now lives nearby and flies from Shobdon airfield at Leominster. Having now built and flown two Titan T-51s, the first one with a Suzuki V-6 and the second example with a Honda V-6, Ben is well placed to contrast and compare these two alternatives. His first Mustang was flown in 2010, the first to be completed in the U.K., where the Light Aircraft Association (LAA) administers the construction and testing process of established and new homebuilt aircraft designs on behalf of the U.K.’s CAA (Civil Aviation Authority). The LAA is both thorough Ben’s T-51D first flew in 2010. It is powered by a 183-hp Suzuki engine. and cautious with project evaluation, particularly with a new airframe, a new powerplant, and a high-performance design. “tuned up” and is rated at 183 hp. As a result, 4200 rpm generates Having flown his first T-51, a T-51D that he named Millie G, Ben a cruise speed of 145 mph, with 23.5 inches manifold pressure obtained a Permit to Fly for his aircraft and the type. His next task was (m.p.), but to get to this, the engine has to work much harder. to obtain approval to fly the aircraft with two on board. He achieved Notwithstanding, Ben says flying the T-51D “has been a sweet and this goal in 2014, making his transits to air displays and airshows much smooth experience.” The Suzuki engine is 100 pounds lighter than more sociable. Ben has now accumulated 310 hours in his T-51D, includ- the Honda, and this makes a considerable difference with “sweeter” ing aerial visits to Normandy and the D-Day beaches for commemora- handling. He also says, “You ride the T-51D fighter-like, and pitch tions and reenactments with other replica WW-II era kit aircraft. stability also has to be on your mind, making it less relaxing in cruise. However, one of the LAA’s required modifications addresses New Fuselage, New Engine this, with elevator down-springs being fitted on all U.K. aircraft to Keen to expand his knowledge of the T-51 and to broaden customer improve cruise stability.” interest in the all-metal design, Ben embarked on construction of Both engines Ben has fitted have the same Autoflight gearbox, a his second T-51 kit in 2014, becoming the first builder worldwide to design by Neil Hinz that originated in New Zealand and has a 2.14:1 complete a Honda-powered example of the “razorback” T-51B. He also reduction. The propellers on both of Ben’s T-51s are also the same: a wanted to expand his experience with different engines and chose to four-blade, constant-speed, hydraulic Whirl Wind 100-4-84. The last fit the Honda J35A6 engine, manufactured in Ohio and used in vehicles two digits designate that the prop diameter is 84 inches. The engine such as the Honda Pilot, to his T-51B. bearers are the same for both engines, so a kit builder doesn’t need to The Honda J35 VTEC engine series is well known, the A6 deriva- finalize his engine option until the airframe building process is nearly tive, a classic V-6 configuration, first being run and operated on the complete. Everything else is structurally the same, although obviously ground in 2005. Its first aircraft usage is believed to have been in the “razorback” T-51B has fuselage construction differences. Both of 2009. In Ben’s application it generates 250 hp, with takeoff rpm at Ben’s T-51s are the “short-wing” (standard) version with a 24-foot wing- 4750, close to its maximum torque. span, although Titan has now developed a long-wing (scale) version to Immediately comparisons with Ben’s earlier Suzuki-powered better use the additional horsepower of the bigger engines. The long T-51D can be made. Also a six cylinder V-6, this engine has not been wing also makes the aircraft look fantastic.

Ben’s T-51B is powered by a 245-hp Honda engine and first flew in 2016. The paint scheme is that of Impatient Virgin, a P-51B that is still flying today.

16 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Basic Engine Comparison (Titan figures)

Suzuki Honda

Size 2.7 L 3.5 L

Displacement 2736 cc 3471 cc

Comp ratio 9:1 10:1

Weight 307 lb 416 lb

Rating 183 hp @ 6500 245 hp @ 5750

In the Air Ben first flew his Honda-powered T-51B on April 16, 2016 at his home airfield at Shobdon, U.K. By 2013, Titan Aircraft Company’s John Wil- liams claimed there were 15 Honda-powered examples flying worldwide, and they had accumulated nearly 400 hours total fleet flight time. Most recently these figures are believed to be 30+ aircraft and total time of around 2000 hours. The opportunity for an independent comparison of the two engine options is still at an early stage, Ben having completed just 10 hours of flight time in his T-51B at the time this was written. He was also Round steam gauges help make the cockpit of a T-51 look adjusting the trim tabs on the rudder and ailerons to reduce stick authentic. forces. Despite these minimal hours flown, he already has many inter- esting comments and comparisons: “With my Suzuki-powered T-51, it of attention and personal responsibility to get the best out of the operates in the late white, early yellow arcs of the airspeed indicator. engine/airframe combination. But now in the Honda-powered T-51, I am only in the yellow. The He also cautions that neither the Titan T-51D or T-51B is the ideal engine installation in my opinion is better, and the airframe looks aircraft for the novice builder or pilot. However, it is a matter of record better. It is all very compact and streamlined. I feel there is a lot of that many builders are novices. pent-up power with the Honda, more than enough for the standard Next on Ben’s agenda is completion of the test flying and the airframe and the standard wing.” accompanying paperwork dossier for his proposal to the LAA. They will A few numbers from Ben’s early test flights include the climb rate. then get their appointed test pilot, Dan Griffiths (who completed a test His T-51B’s empty weight is 1414 pounds and gross weight is 1800 pilot course at Edwards Air Force Base in California), to fly the T-51B and pounds. These are different than the Titan-quoted figures, but were prepare an independent report. The U.K. Permit to Fly will hopefully necessary to meet LAA permit requirements. While the design is a two- then follow. seater, Ben’s aircraft will always be single-seat—the rear passenger seat was replaced with a long-range fuel tank to make ferry flights for Impatient Virgin display flying around Europe more practicable. The paint scheme Ben chose for his T-51B is that of Impatient Virgin. The The quoted 2000- to 2500-fpm climb rate is possible, but in his tests original is still flying with Kilo 6 in Washington State and was restored from takeoff (the airfield is at an elevation of 300 feet) to 2000 feet, Ben by Pacific Fighters of Idaho Falls, Idaho. This original aircraft, 42-106638, has recorded 1700 fpm, initially with the gear down; however, with the was built in 1944 and went to the 361st Fighter Group’s 376th Fighter gear stowed he confirms 2000 fpm. The stall has been recorded at 68 Squadron based at Bottisham, U.K. It was flown (and named) by Lt. mph clean and 62 mph dirty (these figures should be treated with cau- Victor E. Bocquin. It crashed at Downham Market, Norfolk, on June 22, tion as they are observations from the early stages of test flying). The 1945 while practicing low-level flying; Flight Officer Wade Ross bailed cruise speed Ben’s getting is 165 mph at 3750 rpm and 24 inches m.p. out and survived. The P-51’s remains were re-excavated between 2002 with a maximum speed of 190 mph. This could possibly be faster under and 2005, and following the restoration first flew again in early 2011. less restrictive licensing. Ben’s T-51B carries the D-Day markings of this aircraft, but has his wife’s Ben is adamant that the Honda is a great engine for the aircraft, name Mimi on the starboard side, forward fuselage. noting its superior performance over the Suzuki, with lower rpm yet For more information contact Ben Chester-Master at Moccas much higher power. While it is benign in handling on the ground and Mustang Tel :+44 (0)7780 705924 or visit www.moccasmustang.co.uk. in the air, the design’s performance sets it apart. It requires a level —Geoff Jones J

Photos: Geoff Jones KITPLANES August 2017 17 What is Happening on the ADS-B Scene?

The Stratux dual-band “In” receiver is an open-source version of the Stratus II without an AHRS. A separate output device such as a tablet, display, or smartphone is required. A quick review as we move closer to the 2020 deadline. By Dick Sunderland This article is an update on what has (ES) transponder and Universal Access just ADS-B for general aviation (GA). happened in the ADS-B space since last Terminal (UAT) to a 978 MHz trans- ADS-B is used for precision aircraft year plus some other ADS-B items. It ceiver. “In” and “Out” in quotes and location, which is a cornerstone of many is a follow-up to “Juggling the ADS-B caps refer to ADS-B “In” and ADS-B NextGen improvements. Options,” which appeared in the June “Out” functionality respectively. 2016 issue. That article was framework FAA Statistics for the decisions an owner needs to FAA Deadline and The FAA has been quite open about make about installing ADS-B. ADS-B System Specifications issuing statistics on the progress of The only point I would add to that There has been no change in the FAA’s ADS-B “Out.” The statistics highlight article is that as more aircraft are “In” position that they will not extend the several issues critical to owners. First is equipped, good citizenship would sug- ADS-B equipment installation dead- the market’s choice for “Out” frequen- gest that you should equip with “Out” line nor has there been any indication cies. Second is the rate of failed instal- to illuminate yourself as traffic. This is the FAA will be changing the ADS-B lations. Third is the state of installations the same logic as turning on your land- system equipment specifications. My relative to the program’s nominal goals ing lights and strobes during daylight to speculation is that any delay would and the deadline. These will be explored make yourself more visible. Similarly, not be announced until after the cur- in text and accompanying graphs. Due as more targets have “Out,” you should rent FAA Administrator’s term is up in to publication deadlines, the statistics install dual channel “In” to see them. January 2018 or, more likely, just before are as of the end of March 2017. Dual channel “In” is necessary to receive the 2020 deadline. The FAA has stated “Out” aircraft when outside of ground- they will not be sympathetic to procras- Frequencies Being Installed based transmitter (GBT) coverage. tinators because of the long period since The graph of installations by frequencies In the following discussion 1090 ES the regulations were passed. The FAA (Figure 1) shows a very telling difference refers to a 1090 MHz extended squitter has a lot more skin in this game than between cumulative installations to date

18 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes majority of other errors are software installation errors and not the failure of units to transmit. Status of Installations as of the End of March 2017 At the end of March 2017, the FAA showed 22,840 good GA “Out” installations (see Figure 3). That total includes LSAs and Experimentals. GA installations were 1161 in March 2017 and an average of 1107 per month for the first quarter of 2017. There was a notable bump up in the installation rate after the rebate program opened but has since tapered off. The FAA’s installation data comes from analysis of aircraft detected in the air. Many pundits are using a total Figure 1: About 94% of ADS-B “Out” installations are 1090 ES only. Installations of 978 “Out” have greatly slowed, but some aircraft have both. expected GA “Out” installation market size of 100,000 aircraft. This starts from and installations in the last five months. emitters (NPE). Figure 2 shows the an estimate of a GA fleet size of 160,000 The current installations are about 94% percentage of NPEs by aircraft type, less a roughly 20% that are estimated 1090 ES. Shops are corroborating that which has remained surprisingly con- not to use ADS-B required airspace and number anecdotally. It is felt the UAT’s stant over time. The FAA statistics another approximately 20% that are esti- cumulative installed to date is a higher shows that the Experimental and Light mated to be hangar queens. The resultant percentage than recent history because Sport Aircraft (LSA) communities market was then rounded down to a nice some were from the Capstone Proj- have done the poorest job of any of the number that is easy to compute with! ect in Alaska and the Gulf of Mexico categories of “Out” installations. At the Forecasting achieving or missing a projects that essentially prototyped the end of March 2017, 44% of the installa- goal of 100,000 GA installations by ADS-B system using UAT. Also some tions fell into the NPE category. About 2020 is problematic. That is because UAT transceivers were installed early 77% of those NPEs are insufficiently no one knows for sure the number of on when 1090 ES “Out” and dual “In” accurate GPS receivers. Shops feel the installations that will ultimately be units were not available. There are some aircraft with both 1090 and 978 “Out” installations. The reason to have both 1090 ES and UAT “Out” installed is when out of GBT coverage, you will illuminate yourself air-to-air to all “In” aircraft regardless of their receiver frequencies. This is legal as long as one transmitter is suppressed when the other is transmitting. The statistics beg the question is UAT “Out” dead? If it is not dead it is at least comatose. The proliferation of all-in- one 1090 ES boxes, their price com- petitiveness, usually simpler installation and the lack of international adoption of UAT has essentially doomed UAT “Out” to niche status. Installation Failures The FAA tracks failed installations, which Figure 2: Failed Installations are called non-performing emitters by the FAA. About 44% in Fed speak are called non-performing of LSA and Experimental installations fall into this category.

Photos: Dick Sunderland KITPLANES August 2017 19 Figure 3: It is hoped that about 100,000 GA aircraft will have ADS-B “Out” installed by 2020. To date, the number of good installs is significantly less. needed or the capacity of the market to they were going to announce a UAT an AHRS function. A separate output do installations. transceiver enclosed in a blade antenna device such as a tablet, display, or smart Looking at the graph, if you believe at Oshkosh. It remains to be seen if phone is required. Since it is dual-band in linear growth, the goal will not be these are “disruptive technologies.” “In,” you receive “Out” traffic transmis- achieved. If you believe in geometric These units are as yet not TSO’d, so it is sions air-to-air. You will not receive non- growth it could be. My guess is the installa- buyer beware of claims to comply with ADS-B aircraft secondary radar targets tions by 2020 will end up in the mid-range the TSO but not having a certificate. unless you generate a hockey puck (i.e., of the number of remaining installations. Shops report that 1090 ES transpon- you are “Out” equipped) and are within ders with an integral certified GPS both radar and GBT coverage. The cost Hardware Offerings receiver and dual-band “In” are the for the kit is about $130. The kit is eas- There have been no new “Out” hard- winners in the marketplace. This is the ily assembled. Reception performance ware offerings since last summer by the so-called “slip-in” market and uses the seems to be less than installations with big current suppliers. They seem to be traditional in-panel transponder form externally mounted antennas. FlightBox set for the duration. Some new as yet factor. The “In” function either uses an manufactures an already assembled ver- minor players have come into the mar- integral display, hooks up to an existing sion of the Stratux. ket. uAvionix announced a new 1090 ES display, or provides wireless connectiv- transponder at Sun ’n Fun that seems to ity to another output device. The GPS Avionics Shop Perspective set a new lower price point for 1090 ES is not shared with a navigator. This is a I interviewed several avionics shops in “Out” and a new small size. They already natural for older aircraft without a certi- the Denver area as well several avion- offered a similarly small UAT trans- fied WAAS navigator and isn’t subject to ics industry experts. The current and ceiver. Another company announced navigator software upgrades. expected installations through 2017 are There continue to be new announce- seen as being owners who see “In” advan- ments of “In” receivers with almost tages. Shops expect the 2018-2019 cus- universal offering of Wi-Fi connec- tomers to be more of the minimal rule tivity to in-panel displays or tablets. compliant type/no frills installations Many also offer AHRS/auxiliary that may opt for UAT because it may be panel functions, too. The segment nominally cheaper. An industry-wide seems to be more dynamic because installation crunch did not exist at the portable “In” units do not have to meet end of March 2017. Avionics shops and the requirement of a TSO. the industry association expect there The Stratux dual-band “In” receiver will be a crunch in 2018–2019. continues to generate considerable Shops are hiring additional help, but Dynon’s SV-ADSB-472 is a dual-band ADS-B receiver. It receives weather and interest in the Experimental space. The this appears to be mainly a function of traffic on both 978 MHz and 1090 MHz unit is basically an open-source ver- robust hiring across the industry rather frequencies. sion of the popular Stratus II without than for ADS-B installations. As one

20 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes L3’s Lynx is an all-in-one Mode S 1090 extended squitter transponder with 1090 MHz and 978 MHz ADS-B “In.” Shown on the touchscreen display is traffic and terrain awareness. shop put it, they are always looking for brands of equipment, but as one person you pull the trigger. By talking to a shop good reliable people, but those require- put it, you wouldn’t take a Chevy to a now, you can get a feel for the work qual- ments are hard to meet. Ford shop even though they could work ity, find out about their on-time perfor- Typical shop lead times are 30–90 on your car. Finally, you need to estab- mance, and get references. They will be days and fairly static. There is some lish a relationship with a shop so you able to ascertain if any of your legacy seasonality with longer lead times in won’t be a walk-in-cold situation when equipment like GPS receivers, displays, the spring getting ready for the flying season. Some of that lead time is the normal backlog that always exists for custom work. Typical “Out” installations are three days but can average eight days if there are “In” or other upgrades. Shops stress each job is unique and is bid as such and is always subject to surprises. There are no flat-rate guides for installations like those for automobile repairs! Shops are typically not requiring pre- paid installation reservations or equipment deposits. Many shops have test equipment that can verify the installation is working correctly before the aircraft leaves the shop. This is especially important for a shop, as they don’t want to see you twice for the same job. It is important for you if you are flying to a distant home base. A shop installation should include a guarantee that the installation will pass the FAA’s verification test. If you are considering a shop install, they stress it is important to talk with them now. They can use their experience to help you finalize the configuration for your mission and pocketbook. If you have a favorite brand or need to integrate with a particular flight management system, then you need to find the correct shop. Shops have a learning curve with the manufacturers they do carry. If you engage them for work that is not in their experience base, it will cost you more. Most shops will work on all

KITPLANES August 2017 21 encoders, etc. can be logically reused. Be aware that for certified aircraft, a given transponder model can only be paired with specific GPS sources. Avionics shops are surprisingly open to installations on Experimental aircraft. This is in part because Experimental owners are in general more knowledge- Garmin’s GTX 345 is a Mode S extended squatter transponder. It offers 1090 MHz ADS-B “Out” and dual-link 1090 MHz and 978 MHz ADS-B “In.” able about ADS-B, know their aircraft better, and are passionate about the job However, they do not report difficulty and the electronics savvy of the A&P. being done right. with the aircraft owners obtaining the That person is unlikely to have access rebates. They say the rebate program is to ground test equipment for demon- Changes in International drawing in fence sitters rather than the strating ADS-B performance, com- Requirements unaware about ADS-B. As of the end of plex system integration knowledge, or The generally slow pace of global adop- March 2017, about 5000 of the 20,000 sophisticated debugging experience. tion of ADS-B continued in 2016. rebates had been reserved. The publica- Also you will need the services of an Mexico recently announced a 1090 ES tion date of this article is near the expi- A&P with Inspection Authorization requirement for January 1, 2020 that ration date of the program, so watch the (IA) to sign off if the install is part of largely mimics the U.S. “rule airspace” press for further information. a major modification on a certified rules. Canada and the Caribbean coun- aircraft. Unfortunately some avionics tries have not moved toward mandatory Light Sport Aircraft shops have ended up debugging some adoption. No country other than the Light Sport Aircraft (LSA) is a continu- of those A&P installations. That raises U.S. has implemented UAT. ing source of confusion about permis- their ire. They have missed the installa- sible ADS-B options. The confusion tion revenue and inherited a problem ADS-B and UAS/drones arises because the “Out” and “In” equip- situation not of their own making. There is considerable research and mar- ment that can be used is a function of ketplace activity on the UAS/drone side how the LSA was manufactured. For ADS-B “Out” Usage on collision avoidance with aircraft. factory-built LSA (SLSA) and amateur- Both transponders and “Out” (1090 Many schemes are being talked about. built to factory specifications (ELSA), ES or UAT) equipment must be oper- This seems to be driven from the UAS the ADS-B equipment that is installed ated in altitude reporting mode for side where they want to fly out of line of and the method of installation must be transponders and transmit mode for sight and closer to airports. A UAS uti- factory approved. An E/A-B LSA is like “Out” equipment prior to moving on lizing UAT “Out” could be received by any other Experimental aircraft in that the airport surface and at all times an airplane with UAT “In” in air-to-air you can install any equipment you desire when in flight. This is true regardless of mode without having to be in GBT cov- as long as it meets a TSO performance operating in “rule airspace” or not. This erage. Because of frequency congestion, specification. Note that some heritage is true now even though you are not 1090 MHz “Out” for drones is a non- aircraft that comply with the LSA rules required to have “Out” until January 1, starter. To be clear, as of yet, there are are, in fact, certified and must follow the 2020. If you have ADS-B installed you no FAA regulations for “Out” or “In” certified rules and use TSO’d equipment. must use it! for UAS/drones or for “In” for aircraft. Because of their limited perfor- Since UAS/drones are weight sensitive, mance, a smaller percentage of LSAs are Anonymous Mode they are driving miniaturization. expected to elect to install “Out” and A little known feature of ADS-B is what more may choose to install UAT rather is known as anonymous mode, which FAA Equipage Rebate than 1090 ES. only applies to UAT “Out.” Anony- The FAA’s $500 equipage rebate pro- mous mode is the ability to have the gram commenced in September 2016. Installing as Part of an Annual aircraft’s identity “anonymized” under It came with specific gates that must be If you are not self-installing, it may certain very limited conditions. You met by the applicant. The critical ele- be tempting to have your equipment still have to have “Out” operating in ment was that it applied to “Out” only, installed by an airframe and powerplant flight; it is just that decipherable aircraft in single-engine piston aircraft regis- mechanic (A&P) if you are using one identification is not being transmitted. tered before 2016 with required TSO’d for your annual or condition inspec- A user must keep track of the operating equipment. Incidentally, the FAA says tion. This is attractive as the airplane rules and only use the anonymous mode the rebate is taxable income. is already down and probably halfway when appropriate. If you are using 1090 Avionic shops have termed the rebate torn apart. This approach is subject to ES “Out,” your identification informa- program as “disappointing” in impact. the complexity of the work being done tion is always being transmitted.

22 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Anonymous mode may only be used in “rule airspace” when the pilot has not filed a flight plan and is not requesting ATC services and is squawking 1200. If you are entering Class B or Class C airspace, View Video you will be requesting ATC services and cannot use anonymous mode. Logically this would also include communications with a tower in Class D airspace. Visit Us At EAA AirVenture Shops report users are generally Booth # 2104 - 2105 unaware of anonymous mode and even if they do know, they don’t request its installation. It is unclear how practical anonymous mode will be. In the end the FAA could probably still track Why sacrifice comfort for you down through post-event analysis performance and durability? for a violation. With a heat-absorbing Outlast® Resources fabric head pad; plush, full-size Aside from websites cited in my previous article, you should check out the leatherette ear seals; Hybrid Electronic AOPA website. AOPA has been writ- Noise-Cancelling technology and ing ADS-B specific materials for some Bluetooth® wireless − the DC ONE-X time. These articles have ranged from sacrifices nothing...and gives you fundamentals, to experiences install- everything. Including a 30-day, money ing equipment in legacy aircraft, to user back guarantee. And at just 12.3 flight experiences. The easiest access is to go to www.AOPA.org, then click on ounces, it’s the lightest full-featured the search magnifying glass in the top ANR headset in its class. right-hand corner. Enter ADS-B in the window and click “search.” A long list Purchase online from David Clark at of articles will appear, the best of which are by Mike Collins, their ADS-B www.flytheone.com point man. or call 1-800-298-6235.

Not Very Fearless Forecast Made In USA For the balance of 2017 I predict contin- © 2017 David Clark Company Incorporated ® ued 1090 ES “Out” dominance. I antici- Green headset domes are a David Clark registered trademark. WWW.DAVIDCLARK.COM pate continued outreach effort by the FAA to get rid of NPE issues. Shops will show modest increases in installation lead times but no full-fledged crunch. I predict more offerings in the market230-33342REV3- ONE-X Comfort-Durability 4625X7125KP.indd 1 5/3/17 2:49 PM place for drone-based “Out” equipment to announce UAS locations to help avoid collisions with aircraft. Summary and Conclusion Another year has passed. Installations are slowly progressing with avionics shop lead times still reasonable. All-in-one ADS-B 1090 ES “Out” and dual “In” boxes are the big winners. Most buyers are also installing some form of “In.” Safe flying until next year’s update!J

KITPLANES August 2017 23 What’s a Nice Guy Like You Doing in a Plane Like This?

Making the transition from certified aircraft to Experimentals. By Todd DeVito

24 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes The first plane I owned was this Beech Musketeer. I bought it before I had my license The Musketeer lacked speed but hauled a and used it to complete my training. (Photo: Betty Easley) lot of stuff.

We have all heard the comment that beautiful. Sure, she was a bit older than Bonanza. Maybe it was time to consider we must be crazy to fly an aircraft we I was, and definitely more experienced, Experimental aircraft—but first, like built in our garage. Does it make me but this was love. I had mentioned the magazine articles say, I had to define even crazier to fly an aircraft someone I Bonanzas to my instructor during my mission. That was easy: I mostly joy- never met built in their garage? my initial flight training years before, ride, but occasionally take a longer trip. Continue on to discover how a and he told me that any Bonanza I Of course, I needed four seats in case mild-mannered Beechcraft pilot could afford, I didn’t want. He had I wanted to carry people or gear. I also was seduced into the seamy world of to be wrong, didn’t he? Well, I had to wanted performance equal to or better Experimental aircraft. find out. She was at a dealership, so I than my Bonanza, and the long-term I suppose the seed was planted back arranged a trade for the Musketeer and costs would have to be better than the in 2009 or 2010 when I was just a pilot the Bonanza was mine. Bonanza. Since Experimentals in my in training. My prime aviation enabler A few more years went by and I was price range were likely to be less complex mentioned that for higher perfor- still in love, but I was finding out that than my Bonanza, I reasoned that fail- mance and lower cost, Experimental love had a high price. My Bonanza was ures were likely to be less frequent. I also was the way to go. At the time, I was a dream to fly, but when things went knew I would be allowed to do my own still trying to figure out how to get wrong, they were expensive to repair. repair work and call in an A&P for con- my trainer to fly straight, so I didn’t Things go wrong at an alarming fre- dition inspections and repairs that were pay much attention, but the statement quency on an almost-60-year-old air- too big for me to handle. always stuck with me. craft. Then practicalities started to get in There was also the question of if I The aviation bug bit me hard, and the way like other bills and kids going to wanted to build my own airplane. The before I got my license, I purchased a college. Love or not, it was time to start idea of building is very cool, but would Beech Musketeer to complete my train- thinking about moving on. the reality be as cool? I am fairly handy, ing. I thought the big roomy interior I wondered what to move on to. All but have no aircraft-related skills and would be great to haul the family or of the certified aircraft I considered even less artistic or craftsmanship abili- vacation gear in, and it was to a point. had the same age and cost issues as my ties. Also, where would I find the time? With the rear seat removed, I was able to fit in two mountain bikes and enough gear for a weeklong vacation to Sedona, Arizona. However, it didn’t escape my notice that I was barely outpacing traffic as I flew over the highways, and the Mus- keteer had almost no climb performance in the desert heat. A few years went by and I started thinking about something with a bit more performance. Then I fell in love. Her name was Bonanza, and she was

Trading the Musketeer for this Bonanza seemed like a good idea at the time.

Photos: Todd DeVito KITPLANES August 2017 25 The Mustang II’s performance is similar to that of an RV-6, but it Even if I found a great deal on a partially completed RV-9A, the often costs less when bought used. (Photo: LeRoy Cook) cost to get it flying was beyond my budget.(Photo: Mark Schrimmer)

Finally, if I sunk my money into a kit, wants, I changed my mission definition range, so they were still out of the ques- I wouldn’t be flying until the kit was to a two-seat requirement. The reduction, but some RV-6s could be found in complete. That could be many years tion to two seats brought up the ques- the $40,000 range. This was still out of without flying. tion of side-by-side or tandem. For this my league, but was starting to get close decision, I brought in my special advi- to an area I could consider. Sprinkled Plane Shopping sor to the project, my honey. She said through the RV ads was the occasional With all of these questions swirling she would prefer to sit next to me, so we Mustang II or Thorp T-18, and they were around my head, I decided to virtually decided on side-by-side seating. almost always priced lower than the RVs. visit the 800-pound gorilla of Experi- Further research on the website made A little more research showed that they mental aviation: I went to the Van’s me decide that an RV-9A was the best were comparable to RVs, so I added them website (www.vansaircraft.com). It had fit for me. I used the handy cost estima- to my watch list. a very convenient page titled “Which tor and learned that building an RV-9A In the meantime, I had my Bonanza RV is Right for Me?” On the question would probably cost me in the neighbor- advertised on Barnstormers as well. It of needing four seats, it says, “Really? hood of $70,000 plus my time invest- was just one old Bonanza in a sea of old Note the question is ‘need,’ not ‘want,’ ment. That was not even in the realm of Bonanzas. The only calls I got were from or ‘would be kind of nice.’” I thought possibility for my budget. people who wanted to trade for planes I they were talking directly to me. In My next step was to check out the wasn’t interested in. my six years of flying, I could probably Barnstormers (www.barnstormers.com) Then it struck me: There didn’t seem count on one hand the number of times and Trade-A-Plane (www.trade-a-plane. to be much new money entering the I put the back seats to use. Starting to com) websites to see what was available. market. If I wanted to move forward, I learn the difference between needs and RV-9s were in the $70,000 and up price would have to start calling on planes I

The Thorpe T-18 is another alternative to the side-by-side RVs. With over 2600 completions and many other kits still under (Photo: Richard VanderMeulen) construction, the RV-6/6A is the most popular Experimental ever. (Photo: Kai Hansen)

26 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes was interested in to see if they wanted to trade, so that’s what I did. For months, I scoured Barnstorm- ers and Trade-A-Plane, calling on every RV-6, T-18 and Mustang II that fell near my price range. I had some near misses, but nothing panned out. Then I made calls for more months, and then more months after that. And Bonanza bills kept rolling in. Finally, at the end of 2015, I got a call from a friend who had his Mooney up for sale. He was discussing a trade with an RV-4 owner who needed a plane with four seats for his growing family. My friend decided he didn’t want an RV-4, but he put me in touch with its owner. The first thing I did was brought in my special project consultant to see if tandem seating would be OK with her. My honey agreed to the change in requirements, and we were on our way. I traded my Bonanza for the RV-4 on Valentine’s Day 2016. How does it look? Well, I can tell you that it isn’t a show plane. In fact, it looks best from far away. My next hurdle was learning how to fly it. I had no tailwheel experience and had read that pilots often have problems transitioning to smaller aircraft because of the lighter weight and lighter control forces. Did any of this bother me? Of course not! I had a level of overconfidence that could only be born of ignorance. My first stop was back to the Van’s website to check for qualified instructors. As it turned out, Mike Seager, the most senior of the Van’s instructors, lives in Oregon, an easy ten-hour drive from my house, so I gave him a call and got on his schedule. Training with Mike When I got to Oregon, one of the first things Mike asked me was how much tailwheel experience I had. I told him that I had none, and he said I was going to have a steep learning curve. Chinks were beginning to appear in my armor of overconfidence, but it would still be a few minutes before my overconfidence was entirely shattered. We got into the air and I had a death grip on the stick. I was jerking it left and right, and the

KITPLANES August 2017 27 Van’s RV-4 For those of you who are new to Experi- mental aviation or somewhat out of touch, Van’s Aircraft is the largest kit aircraft manufacturer, with over 9650 RVs completed. Van’s offers eight different models, many with a choice of tailwheel or nosewheel configuration. Van’s spans the market with single-seat, two-seat tandem, two-seat side-by-side, and four-seat models. The RV-4 is Van’s second commercially available model; its first flight was made in 1979. It is a fixed-gear, tandem-seat, taildragger, designed for engines of 150 to 180 hp. It can cruise at nearly 200 mph, The RV-4 has a fairly basic panel, but it gets the job done. climb at 1500 fpm, and has a maximum range of nearly 800 miles. plane jumped all over the sky like we We went through two training ses- With reasonably comfortable seating were dodging flak. My dance on the sions a day for three days. Between ses- arrangements, the RV-4 can be used for rudder pedals during ground operations sions, I would furiously jot down notes anything from aerobatics to cross-country was like a drunken bear doing a polka in and questions to ask Mike before my flights. In the right hands, its short takeoff combat boots. Sometimes I would catch next session. I would then try to memo- and landing capabilities even allow it to be the brake along with the rudder, which rize the different power, rpm, airspeed, used for some backcountry access. would add an extra exciting swerve to trim, and flap settings for each leg of Being one of Van’s older kit designs, the my runway polka. the pattern. In the evenings, I would RV-4 is more difficult to build than newer Through this all, Mike was calm and read and reread the flight manual he kits because it does not incorporate manu- collected, making suggestions and giving loaned me. After three days, I wasn’t facturing advances like pre-punched parts. encouragement on those rare occasions ready to fly on my own, so we set up My RV-4 is a pretty basic example of the where I did something right. One of the another three-day session at the end of breed. It was completed in 1988, runs a 150- suggestions he offered to avoid overcon- the month. hp Lycoming O-320 engine, has a basic VFR trolling the plane was to use two fingers During the second three-day session, panel, and a rather spartan interior. It is also on the stick. This helped, but I noticed we focused on air work in addition to a lightweight version of the breed. I haven’t after the training session that I must have takeoffs and landings. The air work had a chance to do a full-performance test had a two-finger death grip on the stick went fine, but I was still struggling with on it yet, but just tooling around, I easily hit because my fingers were cramping. landings. I would flare high and almost 170 mph using partial throttle at 8000 feet and achieve climbs of over 1000 fpm in 90° F heat from my 5000-foot-elevation airport. Three high performance aircraft, only one I look forward to spending time investigat- of which is in my price range ing more of my RV-4’s capabilities. —T.D.

28 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes drop us in or flare low and almost drive us into the runway until Mike called a go-around. At one point, Mike told me I couldn’t fly the RV like a Bonanza. A Bonanza has big wings and will just float its way down to a soft landing on the runway. An RV needs to be flown to within a foot above the runway at the correct speed and then eased into a three-point attitude to get a smooth landing. Until that point, I had no idea that the Bonanza was allowing me to fly that sloppily or that the RV required that kind of precision. Fatigue and frustration began to build up, and after a particularly dismal third day of landings, we agreed that I would have to come back for a third session. When I left, I had no idea how I was going to figure out how to judge where one foot above the runway was. On my drive home that night, as road hypnosis started to kick in, I had an idea. The white line running down the middle of the highway looked a lot like the white line on the runway, and my height off of the road appeared to be similar to the RV’s height off of the runway. If I could just concentrate on that sight picture and lock it into my head, I would have a pretty good approximation of the sight picture I would need when landing the RV. For the next month, whenever I drove on the highway, I tried to concentrate on the sight picture of my car in relation to the road. I went back to Oregon hoping the third time would be the charm. Since all of my other flying tasks had been completed, we spent the entire time practicing takeoffs and landings, and I finally started to get the hang of it. I was still fatigued by the end of the third day, but was flying well enough to earn my tailwheel endorsement. Showtime! The last thing Mike told me before I left was to find a calm day and get the feel of my RV-4 before I tried to fly in any difficult conditions. I planned to get started on that immediately, but Mother Nature had other plans. My first flight was delayed, first due to high winds and then due to a failed

KITPLANES August 2017 29 mag check. I would have taken a certi- until I hit the gas and got into the air 14 to 17 knots higher than my indi- fied aircraft to the shop, but with my again. When I got back to the hangar, cated air speed. This seemed excessive, new Experimental mentality, I decided I was spent and confused, wondering so I turned around and did the same to troubleshoot the problem myself. I how I could have flown so badly. In dis- tests on the way back, in case a tailwind traced it to a fouled spark plug, cleaned cussions with my ground observers, I impacted my findings. Surprisingly, my out the lead blob, and was back on my heard a valuable piece of information. It return trip showed even higher GPS way. No big deal. was mentioned that I was really moving groundspeeds. They were 17 to 19 knots A few days later, after the plane was fast when I entered the pattern. higher than my indicated airspeed. I did back together and another windstorm Now the pieces were starting to fall some quick math, adjusted my pattern had passed, I went back to the airport together. All of these bad landings could speeds down by 17 knots, and landed with a sense of fear and excitement. The be attributed to excessive speed. I started without incident. Instead of looking at plane was running fine, and I got into to wonder if my airspeed indicator was the airspeed indicator issue as a prob- the air. I went for a short flight and came reading correctly. My ground observers lem, I looked at it as a new opportunity back for some pattern work. I flew the and I developed a plan. for troubleshooting and as a chance to appropriate speeds and went through I came back the next morning with get to know my RV better. the correct steps for each leg of the pat- my portable GPS and a paper contain- One of the things I heard during my tern, but badly bounced on the landing. ing a list of speeds from 140 knots RV training and in a forum at Oshkosh On successive landings, I put on quite down to 40 knots. When I hit each last year was that we need to become one a ground-o-batics show with floating, speed on my flight, I checked my GPS with our aircraft. For me, this means balloons, bounces, swerves, and the and wrote down the groundspeed. On learning everything I can about it, learn- beginning of a pilot induced oscillation, my flight out, my groundspeeds were ing to fly it competently so I am confident in all situations, and participating in its mechanical troubleshooting and RV Transition Training maintenance. Obviously, homebuilders I am a strong proponent of transition training. The few planes I have flown have had different can completely immerse themselves in enough characteristics that I have always found a benefit in having an instructor who knows this experience, but Experimental avia- what they are doing flying next to me for the first several hours. It wouldn’t have mattered if tion allows even those of us without the I wasn’t a believer because my insurance company required it. time, skills, or inclination for that kind Van’s has several instructors on their transition training team who fly out of several of commitment to become one with our different states. Each instructor teaches the Van’s syllabus in different models of Van’s aircraft in a way that just isn’t possible aircraft, so check the Van’s website (https://tinyurl.com/k9lue3e) to find what works best with certified aircraft. Experimental for your training needs. aircraft also tend to perform better and As you’d expect, the training covers the types of things you would be doing in a thorough have a lower price. For me, those were flight review or to pass the Private Pilot flying exam. You can expect to taxi, do takeoffs and reasons enough to make the switch to landings, slow flight, stalls, 30- and 45-degree turns, and anything else you can remember fly Experimental. These benefits can from your flight training days. The instructors will customize the training to focus on improv- also be used to convince others who ing your weak points as was done with my need for work on landings. think aviation is out of their reach to I found the Van’s training to be even more beneficial than I thought it would be. Light- join in the fun. J

weight aircraft are so much different than the Beechcraft planes I had been flying that I had D Todd to significantly change my flying technique. I can confidently say that it would have been Todd is a recreational a very bad idea for me to try to fly my RV-4 without specific RV training. The consequences private pilot and renowned likely would have been a damaged aircraft or worse. slacker. He would like to —T.D. build his own plane someday, but let’s face it, that sounds like a lot of work. He can frequently be

e found bouncing his bright

t Vi red RV-4 down the runways Mike Seager offers RV transition training of Nevada, at the Vernonia, Oregon, airport. (Photo: Tedder [CC BY 3.0 (http://creativecommons.org/ California, licenses/by/3.0)], via Wikimedia Commons) Idaho, and o Arizona.

30 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes

Sizing an Avionics Cooling Fan How much is enough? By Norm Ellis Avionics Mooney International Corp.

All electrical equipment in one form was a Lone Star Cyclone 21 DC avionics “Electronic systems reliability is or another generates heat. Lowering the blower rated at 21 CFM, 24 VDC. The strongly related to the temperature environmental temperatures in which fan has three blower ports, and each port of the solid-state components in the the electronic equipment is housed, the has a half-inch inside diameter. system. Component temperatures avionics bay in this case, will extend the are dependent on internal thermal mean time between failures (MTBF) Advisory Circulars (AC) design and external cooling. In eval- of the avionics/electrical units signifi- A piece of helpful information is an uating the temperature environ- cantly (see Figure 1). advisory circular. They are not required ment, consider the additional heat A cooling fan provides a good solution by regulation; nonetheless, they contain generated by the equipment, espe- for cooling avionics/electrical units. This useful information. Here is an excerpt cially in a location where airflow is in turn prolongs the life of these units. from AC 23.1311-1C, Installation of restricted. To determine if adequate Fans are safe, reliable, easy to install, and Electronic Display in Part 23 Airplane, cooling is provided, your evalua- an inexpensive way of cooling. Section 27.0, “Environmental Condi- tion should make maximum use The aircraft I’m currently working tions,” 27.2, “Temperature”: of previous data from comparable on has graphic display units (GDU) for which the manufacturer recommends 52˚ C 12.25% Figure 1: Electronics cooling fans with vents placed in the 126˚ F / glareshield behind the GDU. The line Life Expectancy replacement units (LRU) either have 108˚ F / 42˚ C 25% provisions for cooling or fans have been provided for that purpose. When dealing with avionics/electri- 90˚ F / 32˚ C 50% cal equipment, you need to determine what size fan is required for cooling or removing heat. I use a simplified method 72˚ F / 22˚ C 100% for solving the fan size requirements that consists of four parts: cubic feet 0 10 20 30 40 50 60 70 80 90 100 per minute (CFM) required to cool, exit Percent of Electronics Life Expectancy opening size, location of the fan(s), and source of air. The fan used in this article For every 18° F (10° C) over room temperature, electronics life expectancy is cut in half.

32 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes installations, thus limiting ground or flight tests to those installations that cannot be verified conveniently by other means. When the equipment/ operating environment cannot be verified from previous experience or from an evaluation of temperature values in that equipment location, a cooling test should be conducted.” Sources of Heat The primary adversary to avionics/electrical equipment is heat. There are two sources of heat: the avionics/electrical units themselves and the sun on the glareshield, called solar heat radiation or These line replacement units are cooled by the fan (black box) on the left. gain. The hottest temperature the aircraft will endure is when it is sitting on the deck display (MFD), and line replacement of 59° F, the equipment has been rated (aka the ground for the common folks) on unit (LRU) are provided with fans. It for 158° F. This provides a differential a hot sunny afternoon, not moving, with is safe to assume that these units can be temperature, Delta (Δ) T of 99° F (158° all the electrical equipment on. left out of the equation for solving the F–59° F). The aircraft just might be sit- theoretical total required CFM if, after ting on the deck with its interior tem- Find the Watts Needed for Cooling cooling the avionics, the air is ducted perature melting away at 158° F. Would Sum the watts of the electrical units in out of the avionics bay. Otherwise, they you really want to fly in a plane this hot? the avionics bay. You’ll find this infor- should be included in the calculation The second step is solving for solar heat mation in each unit’s installation man- because the hot air has not been expelled gain from the sun. Let’s say an aircraft has ual. Don’t include the watts generated and is only recirculating in the avionics a black glareshield, surface area of 944 in2 by the fan(s). bay. For example, an aircraft generat- (6.6 ft2). With a maximum internal tem- Always follow the manufacturer’s ing almost 700 watts from the electrical perature of 158° F inside the avionics bay, guidelines. If the manufacturer recom- equipment may only require approxi- minus a maximum outside temperature mends using a fan with a unit, by all mately 300 watts to be cooled. of 120° F, this provides a differential tem- means use one. For example, it is recom- perature of 38° F. Referring to Figure 2, mended that fans be used with the LRUs Determine the CFM Requirement this will produce about 3.3 watts/ft2 solar in our aircraft, and inlets are provided to The first step in finding the fan size is direct the ducted air to the avionics. solving the CFM requirements. Start Some of the units like the primary by solving for the differential tempera- Companies That flight display (PFD), multi-function ture. For example, having a normal day Provide FAA/PMA Figure 2: Solar Heat Gain Avionics Fans Lone Star provides a multitude of fans that include 1 port, 3 ports, and 6 ports. The electrical requirements are 12–14 and 24–28 VDC. The CFM ranges are 6.7, 21, and 45–50. www.lonestaraviation.com/ Avionics-Cooling-Fans Sandia provides 20-CFM fans, with 3 or 5 ports, or an axial fan. The electrical requirements are 14 or 28 VDC. http:// sandia.aero/products Troll Avionics provides fans with electrical requirements of 11–32 VDC and 1 port with 5 CFM. Also available are 14–28 VDC with 3 ports and 7 CFM, and 5 ports with 4.5 CFM. www.trollavionics.com/coolingfans.html A differential temperature of 38° F produces about 3.3 watts/ft2. —N.E.

Photos: Norm Ellis KITPLANES August 2017 33 Figure 3: CFM Vs. Watts

Total watts determines the CFM required. load. Multiply this value by the glareshield speeds and high pressures. In theory, it static pressure increase. Reducing the surface area, 6.6 ft2. This increases the occurs around the speed of sound, which amount of static pressure increase can be heat to 22 watts. There is a caveat here: is at 661.7 knots (760.9 mph) at sea level accomplished by designing in the correct This is neglecting any heat loss from the and 59° F, although this will most likely size exit opening. heat transfer from the outside of the occur around Mach 0.3. The exit opening needs to be the same glareshield into the avionics bay by the size or greater than the entrance open- insulation within the glareshield. Solve for Exit Opening Size ing. The opening(s) can be in a different The third step is to solve for CFM. The exit opening is just as important as configuration: holes, slots, rectangles, Add the avionics/electrical unit watts to anything else in the system. The open- louvers, etc. with varying sizes. Another the solar heat gain value, thus becoming ing has influence over the static pressure. question to ask—is there flexibility to 322 watts. Refer to the CFM vs. Watts It is one of many things that can cause change the size of the exit opening? chart (Figure 3) to obtain the theoretical total required CFM from a fan. Figure 4: Mass Flow Rate vs. Delta T (°F) The objective is to have the mass flow rate or CFM generated by the fan greater than the required mass flow rate or CFM required for cooling the avionics/electrical units. If not, the heat will not be dis- sipated or removed as shown in Figure 4, Mass Flow Rate vs. Delta T. A 21-CFM fan will work just fine to a given point as shown in the example. When selecting a fan(s), err on the side of caution. Go with a fan or total of fans that are at least 1.5 times greater than the required CFM—more is better in this case. The fan provides the CFM for cooling; the only way to increase CFM for cooling is to have a bigger fan or more fans. Beware: The air velocity needs to stay below Mach speed due to compressibility. Compressibility occurs at high Mass flow rate generated by the fan needs to be greater than the mass flow rate required.

34 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Figure 5: Static Pressure Drop Vs. Exit Area

Static affects the exit opening.

Solving for exit size, use the fan per- a .56-inch water drop from Figure formance chart (Figure 6) to convert 6 shows the fan is only producing 2 static pressure/inches of water to static CFM. Is this acceptable for cooling the pressure drop (PSF). Locate static pres- watts being generated? sure drop (PSF) on Figure 5 to deter- When the outlet size is established at mine exit area (ft2) or vice versa. The sea level, the CFM will vary as the differ- static pressure drop (PSF) vs. exit area ential temperature increases or decreases (ft2) chart is based off standard atmo- as shown in Figure 4. As the differential spheric conditions. temperature changes, a greater or lesser Remember, the objective is to keep amount of CFM becomes available from the static pressure increase or CFM the fan for cooling. Resize for the worst- drop to a minimum. For example, case scenario. Figure 6: 21-CFM Fan Performance

0.75 19.0

0.56 14.1

0.28 7.0

0.14 3.5

0.70 1.7

STATIC PRESSURE – INCHES OF WATER 0.00 0 4 8 12 16 20 24 STATIC PRESSURE – MILLIMETERS OF WATER Air ow–SP/CFM

With a .56-inch water drop, a 21-CFM fan only produces 2 CFM.

KITPLANES August 2017 35 (Left) Some avionics manufacturers recommend cooling fans with vents placed in the glareshield. (Right) Very little airflow is achieved from ram air on the ground. Ram air can also lead to ingestion of foreign object debris (FOD) or moisture.

Locate the Fans than to extract the air. Among many Conclusion Where should the fan be located? other things that can hinder exhaust This article provides the basics for cal- The thought of strategically placing fan performance is the outside air pres- culating how much cooling is needed fan(s) directly on the outside of the sure, which always has to be lower than for avionics and electrical units. There heat source(s) might solve some of the the inside air pressure or the fan will are other things that can hinder cool- problems for cooling. However, the not exhaust the hot air out. ing, such as obstructions and restric- downfall is that the surrounding units tions to the airflow’s path. For a simple are neglected from cooling. Having a Source of Air solution, use ducting, baffling, or a ple- main fan for circulating the air flow in The primary source of air should be num to direct the airflow where needed. the avionics bay is ideal; however, there obtained from the cabin air. Very little Check validity of the cooling require- might not be room for one or the effi- airflow is achieved from ram air while ments, then create a prototype for vali- ciency might not be achieved due to flow on the ground. Using outside air or dation; this will determine if the fan obstructions. This might be a sound rea- ram air lends itself to ingestion of for- selection meets the requirement. Never- son for attaching an exhaust fan under- eign object debris (FOD) or moisture theless, this is only a baseline for deter- neath the glareshield. Nonetheless, it into the avionics/electrical units, which mining the proper fan(s) size required is easier to circulate the air out rather could cause harm. for adequate cooling. J CFM, Static Pressure, and Air Velocity There are three separate subjects here: static pressure, CFM and air To achieve 21 CFM there would have to be no pressure drop. In order to velocity. There are two different CFM requirements: the fan CFM and accomplish this, another fan producing an equal or greater amount of CFM at the heat rejection CFM. The objective is to have a relatively low or the exit opening would have to be removing the air pressure. An exhaust fan zero static pressure and a high CFM/air velocity to remove the heat. or a device that would draw the air pressure out would be used. In theory this High static pressure reduces the CFM/air velocity capability, which in would be creating a vacuum. So in order to obtain zero static pressure, the turn reduces the amount of heat rejection available and therefore exit velocity and pressure would be the same as the inlet pressure. may not be able to meet the cooling requirements. Air velocity has to do with removing heat, not cooling. It is not rela- In the real world, full CFM is not possible after static pressure is tive to the CFM heat rejection requirements. Air velocity is controlled introduced, as shown in Figure 6, the 21-CFM fan performance chart. and limited by the performance of the fan. This is separate from the This chart shows how much CFM occurs with a given amount of static required CFM to cool the avionics/electrical units. Increasing the air pressure. As the static pressure increases, the CFM/velocity decreases. velocity only removes the heat faster; it does not cool. The amount of Static pressure and CFM/velocity are inversely proportional to each velocity available, excluding the fan performance, is inversely propor- other. CFM controls how much heat is being removed by air mass flow, tional to the exit area, which is directly related to static pressure. and this is known as heat transfer. Air mass flow is the CFM multiplied Here is an example for this discussion. Refer to the fan perfor- by the density of air. Using a fan for cooling is known as forced convec- mance chart, Figure 6. With a .07 static pressure/inches of water tion heat transfer. drop, the fan is only producing 17 CFM, a 19% drop in CFM. At .56 The fan(s) that provides cooling needs to provide enough CFM to static pressure/inches of water drop, the fan is only producing 2 CFM, remove the heat. In addition, the fan needs to provide enough air a 90% drop in CFM. This lowers the amount of heat being rejected or velocity (in feet per second or feet per minute) to overcome static removed. Does this meet the cooling requirements? pressure or pressure drop in the avionics bay. —N.E.

36 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes

Vortex G en e rato r s on an RV-8 Do they really make a difference? By Nigel Speedy

38 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes There I was, at the annual Van’s Air- craft Homecoming Fly-In, a tasty local beer in one hand and a fistful of raffle tickets in the other. By night’s end the raffle tickets had transformed into a set of STOLSPEED vortex generators (www.stolspeed.com). So while I was perfectly happy with my RV-8’s handling qualities, installing the vortex generators (VGs) seemed like a great opportunity for education and recreation. The generic list of benefits of VGs claimed by manufacturers is extensive: lower stall speed, lower liftoff speed, shorter takeoff and landing, improved controllability and safety, easier landing, crisper aileron response, less tendency A line made with a Sharpie or electrical tape was used to keep the VGs in a straight line. to drop a wing in a stall, a mush rather than a break at stall, easier and quicker USD (wing kit), $65 USD (tail kit) with Next was to peel back the covering of stall recovery, and more elevator control postage $7 USD (worldwide). the pre-cut adhesive sheets; an X-Acto at low airspeed—all with little to no loss Instructions for fitting were down- knife worked well for this. The VGs were of cruise speed. loaded from the company website. The firmly pressed onto the adhesive layer They are designed to do this by add- VGs were made from a flexible UV- then removed from the sheet, taking the ing turbulence and energy to the bound- resistant polycarbonate. The base was adhesive layer with them. ary layer, so that the flow stays attached oval shaped, 1 inch long, and 0.4 inch There were three templates supplied: at higher angles of attack (AoA). The wide. They were 0.4 inch high with a 1.2 inch (30 mm) spacing for the hori- first order effect is that the slope of coef- sweep of 27° and had rounded corners. zontal tail, 2.4 inches (60mm) spacing ficient of lift (CL) versus AoA remains The bases were also slightly curved to for the wing in front of the ailerons, and constant, but the stall AoA is increased. allow a better fit to the aerodynamic 3.5 inches (90mm) spacing in front of This higher stall AoA results in a higher shape of a wing. If they are to be fitted to the flaps. The template places the VGs CL at the stall. The higher CL means that a flat surface, they can be easily flattened at 18° to the chord. The instructions Lift = Weight can be achieved with lower by a few strokes on a sheet of sandpaper advise placing the VGs on the bottom velocity (lower stall speed). I set out to lying on a flat surface. of the horizontal tail 4 inches (100mm) put the various VG claims to the test on There were 120 VGs in the wing kit in front of the elevator hinge line. For my specific aircraft. and 80 in the tail kit. Mounting the the wing it was suggested to place them VGs was quite easy and simple. Exclud- 8–10% of the chord from the leading Installing the VGs ing paint, it would be a morning’s work edge. The RV-8 wing has a chord of 58.5 STOLSPEED VGs are made in Austra- to apply the VGs to the tail and wing inches; I placed the front of the VGs 4.75 lia and come neatly packaged with laser- of an RV-8. inches aft of the leading edge where a cut adhesive and templates. At the time The first step was to clean the surfaces rivet line made for convenient marking. of writing, the VGs were priced at $97 of the wing and the bases of the VGs. This put the front of the VG at 8.1% and

The VGs are made from flexible UV-resistant polycarbonate and An X-Acto knife was used to peel back the covering of the pre- come in adhesive-backed sheets. cut adhesive sheets.

Photos: Nigel Speedy KITPLANES August 2017 39 A template was used to keep the VGs spaced evenly. VGs installed on the bottom of the horizontal stabilizer. the rear of the VG at 9.8% of the wing Flight Profile conditions between different configura- chord. A line made with a Sharpie or Each flight followed the same profile. I tions. The tests I flew are shown in the electrical tape was used to keep the VGs took off with 25 gallons of fuel, which Tests Flown table. in a straight line. put the start weight at 1496 pounds Tufts for visualizing airflow were (mid) and cg at 79.8 inches (forward). I Airflow Characteristics made from 6-inch lengths of black wool flew each flight in the same sequence and To allow visualization of the airflow in attached with electrical tape. Chordwise at the same pressure altitudes. This was different configurations of flap and VGs, I attached them at 25%, 50% and 75% to minimize the variations in ambient I tufted each wing. As AoA increases, on the wing and also in the middle of the ailerons and flaps. Spanwise I attached Configurations Tested them every second wing rib. Configuration Purpose Once the position of a tuft had been Clean: No VGs or tufts To baseline performance and handling determined, I taped the tuft to the wing with the long end toward the Tufts on wing, no VGs To determine effect of tufts leading edge. Then I folded the long Tufts on wing, VGs under the horizontal tail To determine effect on elevator authority and forces end back over the tape. Finally, I used Tufts on wing, VGs under horizontal tail, and To determine effect on aileron authority and roll a second piece of tape to hold the tuft on wing in front of ailerons performance firmly in place. A GoPro camera was used to record Tufts on wing, VGs under horizontal tail, and To determine effect of complete installation the tufts. I tufted both wings even on wing’s full span though I only videoed one. This was Tufts removed with all VGs installed To remove effect of tufts to prevent any potential asymmetric behavior caused by tufting only one Tests Flown wing. Be careful applying tufts to a Test Reason laminar flow wing; this seemingly small change can result in large and adverse Stalls: Idle power, flap 0°, 20°, and 40° Test stall speed and characteristics changes in climb rate, stall speed, and Base-turn stall: 10-inch MAP, flap 40° and 20° angle Test tendency to drop a wing stall characteristics. of bank Roll rate in takeoff configuration: WOT, 2500 rpm, Test for crisper and more positive aileron response Configurations Tested 75 KIAS, flap 10° I did a series of six flights, each of about one hour duration. The configurations I Roll rate in landing configuration: 10-inch MAP, Test for crisper and more positive aileron response 2500 rpm, 75 KIAS, flap 40° flew are shown in the table below. When I constructed my plane, I Aileron roll: 140 KIAS, full aileron deflection Test for improved controllability and characteristics installed string potentiometers attached Cruise performance: WOT, 2500 rpm, 10,000-foot Test affect on cruise performance to the controls that are read by the pressure altitude engine monitor of the Dynon SkyView Landing: Flap 40°, VREF 1.25 * VS, 3-point attitude Test ease of landing and distance EFIS. This allowed me to generate the on touch down plots of control positions versus airspeed, AoA, and pitch and roll attitudes Takeoff: Flap 10°, tail down allowing aircraft to fly off Test liftoff speed and takeoff distance that accompany this article. when ready, then accelerate to 70 KIAS at 50’ AGL

40 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Tufts were installed with a single piece of electrical tape and worked fine. Doubling them over helps them stay attached at high speed, but below 200 knots it probably makes no difference. flow over the RV-8 wing first begins to separate at the inboard trailing edge and then moves diagonally outboard to the tip leading edge. With flap settings greater than 10°, the airflow over the top of the flaps was separated. Adding VGs in front of the flap did not cause the airflow to remain attached to the flaps. VGs in front of the ailerons did keep airflow attached to the outboard ¼-span of the wing during stalls when the inboard ¾-span was separated. In cruise without VGs the tufts would lie close to the wing. Placing VGs in front of the ailerons and flaps caused the tufts at 25% chord to rise up approximately 1 inch, while the tufts at 50% and 75% would remain close to the wing. This change in flow may be responsible for the change in cruise speed that I saw. VGs on the bottom of the horizontal tail reduced the stick force per G by about one-third. The stick forces per G were not as light as being at the very aft cg limit, but the reduction was still noticeable. Stall Speed Stalls were done with the throttle at idle, propeller full forward, and elevator aft to achieve approximately 1-knot-per- second airspeed reduction. After the nose dropped, full aft stick was applied and held for two seconds to capture

KITPLANES August 2017 41 Stall with flaps up, no VGs.

post-stall behavior. I defined the stall as forward and 100% being full aft. AoA the point where either pitch attitude or is in dark green, 0% is the no-lift AoA, AoA began to reduce while the stick was and 100% represents the stalling AoA still moving aft. In all cases tested the with 40° flap. peak AoA was achieved before running Pitch and roll angles are shown at the Stall with flaps up and VGs. out of elevator travel. The wing, not the bottom, with positive values representing elevator, limits stall speed in this RV-8. nose-up and right bank angles. Negative The addition of VGs under the horizon- values represent nose-down pitch and tal tail did not reduce the stall speed. left bank angles. VGs on the leading edge visibly altered the airflow over the wing, but this did Post Stall Behavior not translate into lower stall speeds. Without VGs the aircraft was quite con- The horizontal axis of the stall graphs is trollable during stalls. With the stick time in seconds. I spliced together results held fully aft there was a slight wing from a stall without VGs followed by a rock of ±5°. The pitch attitude oscillated stall with VGs, hence the small gap in data. between +15° and +5° as the aircraft On the vertical axis of the stall graphs, stalled and unstalled. Ailerons oper- the airspeed is in dark blue. The elevator ated in the normal sense while stalled, position is in red, with 0% being full although less effectively.

Stall with flaps at 40°, no VGs.

Stall with flaps at 40° with VGs.

42 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes In a coordinated base turn, the normal behavior of my aircraft is for the pitch attitude to drop and to roll toward wings level at the stall with stick full aft, regardless of the initial turn direction. The addition of VGs did not alter these characteristics. Stall Recovery In all cases tested, simply relaxing aft stick forces and allowing the elevator to float to the trimmed position resulted in immediate AoA reduction and stall recovery. This stick movement was from 100% (fully aft) to 65% (1.5 inch aft of center), a total distance of 3.5 inches forward. This recovery control input was consistent in all flap and VG configurations. This input was very easy to make and took less than a With VGs installed the AoA and pitch this is an improvement in stall charac- second, requiring little skill or judgment. attitude reduced before full-aft eleva- teristics, but you would only see it if you The addition of VGs did not improve the tor was reached, so there was still a stall held the stick full aft for a few seconds ease or time to recover from a stall. break and not a constant pitch attitude after the aircraft had already stalled. If or AoA mushing behavior. The addition you relaxed the aft stick pressure at stall Roll Performance of VGs roughly halved the magnitude warning, stall buffet, or as soon as the I interpreted the claims of increased of roll and pitch oscillations post stall nose drops, you would not see any differ- slow-speed controllability to mean that with full aft elevator. You could argue ence due to the addition of VGs. the steady-state roll rate for a given lateral

KITPLANES August 2017 43 stick input was increased. As for the improved characteristics and crisper aileron response, I took that to mean that the steady-state rate was achieved faster (i.e., a shorter roll mode time constant). I conducted rolls using full lateral stick inputs through 90° of bank in the takeoff (WOT, 75 KIAS, Flap 10°) and landing (10-inch MAP, 75 KIAS, Flap 40°) configurations. I also did aileron rolls at 140 KIAS. Placing VGs in front of the ailerons did not cure the slight oscillation in lateral stick that is felt at full deflection during aileron rolls that is typical in the RV-8. The addition of VGs did not alter the maximum roll rate or reduce the time taken to get to the steady-state roll rate in any configuration tested. On the accompanying graphs the vertical axis is both aileron input and roll rate. Full left aileron is 0%, and 100% corresponds to full right aileron. Negative numbers indicate roll rate to the left and positive numbers indicate roll rate to the right. In the takeoff and landing configurations, it takes approximately 0.7 second to accelerate to the steady-state rate of 65° per second. Aileron roll rates were higher at 125° per second. Cruise Performance Cruise performance was tested at 10,000 feet pressure altitude using WOT, 2500 rpm, and sweeping the mixture from ~14 gph (full rich) to ~7.5 gph (50° F LOP) in 1-gph steps. I let the airspeed stabilize for 3 minutes after each mixture change before recording data. With each addition of tufts and VGs, there was a slight reduction in speed at any given fuel flow. Addi- tion of tufts alone reduced speed by 1 KTAS. Adding the VGs under the horizontal tail reduced speed by an additional 1 KTAS. Placing VGs on the wing leading edge in front of the ailerons cost another 3 KTAS. Com- pleting the VG installation in front of the flaps reduced cruise by another 2 KTAS. Removing the tufts increased the cruise speed by 2 KTAS. The net effect was a full VG installation reduced the maximum cruise speed by 5 KTAS. On this specific

44 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes aircraft, installing VGs definitely reduced the cruise speed and made it measurably slower than the clean aircraft. Maximum cruise speed was reduced from 187 KTAS to 182 KTAS (-5 KTAS, -3%). Takeoff Takeoff performance was conducted on Runway 24 at California City (L71). The configuration was flaps 10°, -mix ture rich, propeller full forward, brakes held until 2300 rpm, then throttle was briskly applied. The tail was held on the ground until the aircraft flew off in a 3-point attitude at a liftoff speed of 50 KIAS. Previous testing in my aircraft with a differential GPS has shown this to result in the shortest ground and air 3-point attitude. This resulted in touch- tailwheel aircraft, the pitch attitude at distances. The fact that the aircraft flies down speeds just above the stall. Moder- touchdown is fixed by the geometry of off the ground in the 3-point attitude ate braking was used to bring the aircraft the landing gear (assuming you don’t of 11.5° nose up is indicative of the fact to a full stop. want to land tail first), which in my air- that the wing is not stalled, and video of As the addition of VGs did not craft is 11.5° nose up. Even if the VGs the wing tufts also confirmed this. lower the stall speed, the approach did increase the stalling AoA, it would Once airborne, pitch attitude was speed also remained constant. In a not be an advantage on landing in this adjusted to achieve 70 KIAS at 50 feet agl. The ground, air, and total distance to 50 feet was measured using the onboard Dynon GPS. While not as accurate as a differential GPS, the use of airspeed and vertical acceleration allowed distances to Print and Digital be measured accurately enough to identify gross changes. The addition of VGs did not change the liftoff speed or takeoff distances. One general caution with getting an aircraft with a tractor propeller airborne at the slowest possible speed is that while the elevator and rudder are quite effective, the ailerons are not. My aircraft roll rate at 50 KIAS is half of that at 70 KIAS in the takeoff configuration. If you get a significant roll disturbance close to the ground at low speed, you might not have the roll control authority to counter it. Landing Landing performance was also conducted on Runway 24 at L71. Approaches were flown with flap 40° using the PAPI for glideslope guidance and a VREF of Either Format – Great Savings! 64 KIAS (1.25 * VSO). The throttle was smoothly reduced to idle starting at ~15 Subscribe Now at www.kitplanes.com/subscribe feet agl, followed by a flare to land in a

KITPLANES August 2017 45 aircraft, as it is not stalled in the 3-point Summary of Test Results attitude. For this reason the landing distance remained constant as well. Claimed Advantage RV-8 Test Result Minimizing landing distance by using Lower stall speed No change a slow final approach speed (Van’s recommends a faster Vref of 1.4 * Vso) resulted Better post-stall characteristics Reduction in roll and pitch oscillations in flying in a region of negative flight path stability, which required very close atten- Easier/quicker stall recovery No change tion to airspeed on final (controlled with Better roll performance No change pitch attitude) and rate of descent (controlled with power). A noticeable differ- No loss of cruise speed Reduced by 5 KTAS (-3%) ence during landing with VGs installed was the longer grace period between flare Takeoff distance/liftoff speed No change and touchdown. Without VGs, if I flare Landing distance No change and hold off a few inches above the runway, the aircraft tends to abruptly tran- Easier landing More time during flare to finesse landing attitude and touchdown sition from flying to falling. With VGs the aircraft tended to settle more gently aircraft: These specific VGs are not fuel apply to any specific aircraft, and this is and provided a greater time to finesse the tolerant, so some care needs to be taken what I found. landing attitude. This change is some- when refueling. The addition of VGs In my case, the VGs did not alter thing that the VG manufacturer high- makes cleaning the area around them the stall speeds. There was a noticeable lights as a major improvement. slightly more difficult. These specific VGs reduction in post-stall pitch and roll had rounded corners and were soft and oscillations, but there was no signifi- Living with VGs pliable, so there was no danger of injury. cant improvement in ease or speed of Here are some additional things to Aesthetics are in the eye of the beholder, stall recovery. The stick force per G was consider when mounting VGs to your and I am sure three pilots would have lightened somewhat. The roll perfor- four opinions on how they look. mance of the aircraft was unchanged in any configuration. Cruise performance Safety was reduced. Takeoff and landing dis- While you may hope that adding VGs, tances were not altered. The flare to or any other significant aerodynamic landing was more forgiving to errors in modification, will improve the charac- level-off height. teristics of your aircraft, you should be The fact that the addition of VGs did prepared for surprises. Pay particular not vastly improve the RV-8 without attention to the skid ball when stall- any penalty is a testament to its funda- ing. If you hold the aircraft in a stall and mentally sound design. Don’t take these manipulate the ailerons and/or rudder, results as a vote against VGs on other air- be prepared for the aircraft to depart. craft types; with different priorities they Practice spins before you embark on a could prove to be a very economical and modification program that will likely effective improvement.J

alter the stall characteristics. Build-up Speedy Nigel to fully stalling the aircraft; begin by Nigel Speedy started flying recovering at stall warning, then at the helicopters with the buffet, then immediately when the nose Australian Army and is a drops or when you reach full aft stick. Do any stall testing high enough that graduate of the U.S. Naval you can recover from an unintentional Test Pilot School. He spin. Also consider wearing a parachute currently instructs at the and helmet. National Test Pilot School in Mojave, California. Nigel Conclusion The table on the top of this page enjoys flying his Van’s RV-8 shows a summary of my test results. It and the freedom of E/A-B to was probably a bit optimistic to expect experiment. that all the generic claims of VGs would

46 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes The Creative Homebuilder Simple Tools for Setting Smooth Pop Rivets By KITPLANES® Staff When setting an aluminum pull (or “pop”) rivet, some- While pop rivet angle adapters are familiar to many, our times the hole in the pulling head is a little too large and Creative Homebuilder has been using them for 30+ years and a “feather” of aluminum is pulled into the hole, leaving a picked up a few tricks along the way. Take a quarter-inch round slightly rough surface at the rivet’s face. In order to get an rod, cut one face square and cut the other face back at an appro- absolutely smooth finish, our Creative Homebuilder made priate angle to provide relief from interference with the nose of a little handle. The hole at the tip is as close to the mandrel the riveter. Then drill a rivet-shank size hole in the center of the diameter as possible, and a little bend to the handle accom- adapter and paint the adapter a bright color to facilitate recov- modates ergonomics, putting the handle at a convenient ery of the small piece. Once the paint dries, place the adapter angle when pulling a rivet. As the rivet is pulled, no alumi- over the rivet and bend the rivet shank until it is square with num can be “cold worked” into the original hole in the pop the angled face. Finish by pulling the rivet. This technique also rivet gun, guaranteeing a smooth surface. lessens the “feather” issue mentioned above. J

Pop rivet “tight fit” pull sleeve. Close up of the whole assembly in a pop rivet gun.

(Above) Pop rivet angle adapter is painted red to facilitate recovery when the stem breaks and the gun separates from the skin surface. (Right) Close-up of the pop rivet angle adapter placed in a pop rivet gun and ready to install a rivet. A similar technique is to use a small piece of AEX wedge in place of the Side view showing handle-to-rivet interface. beveled round rod.

Photos: KITPLANES® Staff KITPLANES August 2017 47 Engine Failure! Are you prepared? By LeRoy Cook

Large, smooth, flat fields are wonderful places to land if you have no better choice.

Probably no other in-flight scenario nothing more than a lapse in basic air- a carb-heat test is always on the pre- gives pilots more concern than having manship. One of the PIC’s duties is to takeoff checklist. In actual experience, an engine quit. Especially if there’s only continually know the fuel state and plan it sneaks up on us, building up gradu- one. The likelihood of having a sudden, accordingly. I once had to fly a Cessna ally until the throttle is wide open and catastrophic engine failure is rare, we 150 out of a rough wheat field because rpm is still falling. And when we belat- like to think, but it does happen. Sur- it had been parked there with dry tanks, edly pull the knob to “hot” and there’s viving a sudden propulsion stoppage can all because the pilot “wished” the gas not an immediate resurgence of power, depend on planning and preparation. would last long enough to get him we shove it back to “cold” and try some- home; it didn’t. thing else. Wrong. Leave the carb heat Induced Failures Switching tanks at the first sign of an on until it has time to work, and be pre- Right away, we need to talk about the engine faltering is basic procedure; turn pared to adjust mixture to balance the induced failures that were caused by on the boost pump only after selecting a lower density of the hot air. Expect some improper management, usually fuel star- fresh tank. If you’ve run a tank dry, the initial roughness as the melted ice goes vation, and by deferred maintenance, pump will only put air in the line. Use through the engine. such as ignoring signs of ill health. If the boost after switching until the engine Don’t fail to keep oil in the engine, and fuel system is properly designed and smooths out. Cessna pilots habitually if you have an engine that’s using oil at operated, and we don’t try to stretch the leave the selector in “Both” position, non-typical rates, and the exhaust stack flight beyond the available endurance, but this is a bad idea when fuel is not shows black, oily residue on the cowling, we can probably eliminate more than plentiful. Using a single tank, alterna- give the engine proper attention. If your half the engine-failure incidents. Sev- tively, will maintain a reserve supply, engine no longer develops full static rpm eral times a year, we learn of an airplane and it also gives a fresh, unstirred tank within specs when the throttle is opened involved in an off-airport landing, and to relieve vapor locking. for takeoff, find out where the power we always have to wonder—was there Carburetor ice has been around since loss is happening. Abnormal noises fuel in the tank? We’ve all been guilty of the early open-cockpit days, but it still shouldn’t be ignored; a change in engine cutting it too close sometimes, which is catches pilots by surprise, even though health requires investigation.

48 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes From above, it’s difficult to ascertain a pasture’s suitability for landing. It should be long, level, and oriented into the wind; land as softly and slowly as possible.

Be particularly attentive, and cau- Second, check around the area for in your emergency procedures check- tious, after the airplane’s been worked your best landing site. There’s no point list as it applies to cutting switches and on. You, or the mechanic you hired, can in gliding away from the only good spot unlatching doors prior to impact. have a bad day, overlooking some detail. within reach. You should already know My first engine-out landing resulted the wind direction as a well-informed No Two Alike from a loose oil screen plug, which was pilot; plan to establish a downwind leg I’ve had various emergency landing to be torqued and safety-wired after the beside your landing site at an altitude scenarios over the years; dealing with oil change, but wasn’t. I was only a low- sufficient to make a turn into the wind each one required a different proce- time private pilot, but I heard the engine for the touchdown. dure, so be prepared to make the best noise change slightly, and when I looked Third, do an in-cockpit drill to alle- of whatever happens. In one instance, at the oil pressure gauge, it was on the viate the engine problem if you haven’t a connecting rod failed right after take- low redline. Fortunately, I was still close done that automatically while taking off. The prop stopped instantly, there to the departure airport, so I pulled the care of the first two priorities. Engines was 200 feet of altitude to work with, mixture and stopped the prop to save need fuel, ignition and air to run; thus there was little decision-making the engine and successfully glided back change tanks, turn on the boost pump, involved. I simply dead-sticked to a to a crosswind runway. adjust mixture, pull on carb heat, switch landing spot straight ahead. OK, you didn’t induce the failure, but mag positions, whatever you have avail- In another example, the engine began the engine still failed. What then? able in your aircraft. Don’t pursue trou- vibrating severely at about 3000 feet agl Hopefully, you have trained and pre- bleshooting while you lose control of the in cruise. There was time to turn toward pared for this eventuality. When the landing process, however. a nearby airport, do some exploratory engine quits, you will first hit a moment Next, emergency communication troubleshooting while slowing in level of denial—“Oh, this can’t be happen- duties require prioritizing. If you’re flight, and plan for a forced landing ing!” Yes, it can and it is. Then you already in contact with ATC, let them under partial power, crossing several encounter panic, which is counterpro- know your situation and solicit their landing spots before eventually reaching ductive because it interferes with ratio- help, if they are able to provide vectors the airport. One cylinder had broken a nal thinking. Training is the solution to to airports or terrain orientation. Don’t base hold-down stud. the panic phase. Go to work, doing what waste valuable time and attention on the These two situations required entirely you know needs to be done. radio if landing is imminent. Turn the different responses. Unlike typical train- The first task is to maintain control radio off if it’s a distraction. ing scenarios, engines don’t always stop of the aircraft; minimize altitude loss Finally, brief passengers in a calm completely and suddenly. The propeller by immediately trimming to best glide manner: “We are going to land because will continue to windmill unless the speed, which you should know by heart. of engine trouble; have your belt and engine comes apart internally. Vibration Avoid the stall, yet don’t let airspeed harness tight. Expect some rough is to be expected if partial power is still build up with the nose down, wasting the bounces, but we’ll be all right.” Be pre- being developed in some cylinders. The energy you have stored underneath you. pared to follow the recommendations amount of altitude you have available

Photos: LeRoy Cook and Paul Dye KITPLANES August 2017 49 determines the radius of action you can If the one-and-only engine quits, that pasture was a nice piece of ground, explore and the time you’ll have before there is a very finite amount of time it would have been plowed up.” committing to a landing spot. You must and altitude with which to make a deci- Don’t worry about preservation of the work with what you have. sion. The best possible option is an air- airplane; your task is to protect its occu- In a lot of cases, the engine doesn’t port, any kind of airport, and if you’re pants. The wrecked plane will belong to fail completely, and that means you’ll sitting at two miles above the earth, the insurance company, so sacrifice it to have decisions to make. If it’s still mak- you may be able to reach a runway ten land softly and decelerate progressively, ing power, how much thrust is it making, miles or more away, particularly if run- avoiding a sudden stop to minimize and will it sustain level flight? Remem- ning downwind. Lots of altitude also injury. Separation of the landing gear, ber, there’s no guarantee a partially run- brings the complication of having lots wings, tail, and engine compartment are ning engine will keep going long enough of choices, versus a low-level failure that energy absorbing events that can help to reach an airport. Have alternatives leaves you pretty much in a position you ride through the smash. The impor- picked out. Can you cure the problem? to land on whatever’s right beside you. tant thing is to fly as far into the crash Keep track of which mixture or throttle Make up your mind, and don’t vacillate as you possibly can, never abandoning setting brought the best response. without good reason. what control you still have. Head directly toward an airport if Do the best you can with what you If in a retractable, should the gear be there’s one near, but don’t overestimate have available. Buildings and trees have left up or put down? My reasoning is, your gliding ability, particularly into to be avoided. Roads, while tempting, gear up if landing on water, gear down a headwind. When you’re down to the carry the risk of obstructions like wires, if landing on the ground. The fran- last 1000 feet, have your mind made signs, and mailbox posts. Busy high- gible gear is worth shedding in rough up; turn into the wind, choose the best ways have traffic to contend with, which terrain, so put it down, along with the option, and land as softly as you can. may not be flowing into the wind like flaps. If you have presence of mind, cut you’d prefer to land. In western ranch the master switch and turn off the fuel Pulling It Off country, vacant rural roads may be per- before the landing. Reduce speed at Let’s face it; there’s luck involved in fect. Landing near a highway is a good touchdown as much as possible; that any off-airport landing. My grandson choice, so someone could possibly come factor, plus a tightened harness, is the learned in fifth grade the other day that by to check on an airplane that’s vis- single most important ingredient in a only one-eighth of the world’s surface ibly out of place. Crop fields will result survivable crash. is farmland. The rest is oceans, forests, in some damage, but can offer ample mountains, deserts, and cities. Even the survivable space in which to put the What to Do After the Stop best-looking pasture can have a ditch aircraft down. A nice tempting pasture Whew, we’re down. Now what? Take or gopher colony you can’t see until it’s may harbor ditches and burrows; avoid stock of the situation and act accord- too late. You will have to use the biggest, terraced fields if possible, and land par- ingly. Check for injuries among the softest thing you can find; it may be allel to the terraces if there’s no better occupants and tend to their needs. Fire nothing better than a parking lot, golf choice. As one old-timer told me, “A is the first concern, requiring immedi- course, roadway, or beach. planted field is a better bet, because if ate evacuation in an upwind direction.

If you are fortunate enough to have an off-airport landing that ends on a deserted road that is adequate for a subsequent takeoff, do so carefully, and only after solving the problem that put you there.

50 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes phone service, which greatly reassures and simplifies, but do you know exactly where you are? A GPS will let you tell people your location, but not always how to get to you. After my last off-airport forced landing, I was sitting beside a rural gravel road, but there was no traffic on it and I walked 3.5 miles, knock- ing on many unoccupied doors before I could find someone home in the middle of the day. Fortunately, it was mild weather, and I was in shape for the trek. The point is, fly in clothing suitable for the country you’re flying over. We like to think our airplanes are Once the airplane is safely on the ground, it’s time to find the source of the engine failure. dependable, and we spend considerable As a by-product of the field’s rough surface, the battery cable loosened and the landing- light wire disconnected. effort to keep them that way. Neverthe- less, a forced landing can happen, as I If the plane is upright and relatively if there are no fatalities. Remember that can attest from experience. Look at undamaged, egress normally and assem- the FAA is also in the enforcement busi- the area under you once in a while, and ble the group; don’t go back to retrieve ness; cooperate cautiously. consider where you would put the air- belongings until you’re sure there’s no If nobody’s around, you’ll have to craft down if the engine quit. As in all danger. If the airplane flipped inverted, decide how to proceed. If you were talk- flying, if the unthinkable does happen, be careful to brace when releasing seat ing with anyone before the event, or take command of the situation, work belts or you may suffer injury from drop- you were on a flight plan, a search will the problem, and don’t give up until the ping to the ceiling. be starting shortly. See if you have cell dust settles. J Once out of the plane, settle your nerves and go about taking care of things. Shut off the fuel and turn off switches, but first check for ELT activation. If you don’t need assistance, turn the ELT off so it won’t activate during retrieval of the aircraft. Remove valuables and whatever you need for survival. If in a remote area, stay with the aircraft, which may be your best shelter for now. Now to seek help. Perhaps people are already gathering; guard your state- ments to keep from incriminating yourself on the evening news (“looks like I ran out of gas”). Law enforcement and first responders love to have something unusual to take care of like an airplane crash. Let them work, but give them guidance. Insurance-wise, you have a duty to preserve the wreckage, and the NTSB also needs to be informed before it’s moved. Under Part 830 of its regulations, it’s the NTSB that has investiga- tive responsibility, so you have to notify that agency if the forced landing quali- fies as an accident. The FAA, on the other hand, may be delegated responsibility for the investigation, particularly

KITPLANES August 2017 51 Scale Model Structural Testing By Eric Stewart

The SR-1 scale spar supporting a load of 380 pounds during a deflection test.

This article continues our series of less investment of money and labor than encourage you to read Stan’s article, but investigations into testing of materials testing full-scale structures. The basic the takeaway points are as follows: and construction techniques used on idea is that material properties—namely, • All aspects of the model that see a composite aircraft. So far we have looked strength and stiffness—have fixed val- significant load should be included exclusively at sandwich coupons. How- ues, and that by applying a scaling fac- in the scale model. Failure or inabil- ever, this article will look at scale model tor lambda (λ), the performance of a ity to do so invalidates that aspect of testing, and as such is applicable to any scale model can be used to model the the model. This does not necessarily form of construction method—com- performance of the full-scale structure. invalidate the model as a whole, if one posite, metal, tube, wood—assuming A knock-on benefit is that building a is careful to consider the effect of non- you are able to appropriately scale the model can allow you to hone your skills scaling structures. dimensions of the constituent materials. and construction strategy on a small • The model should be as large as prac- If you’ve been following this series, project before tackling a larger one. ticable so that errors induced from you know by now that we like to Stan Hall, an avid sailplane pilot and scaling are minimized. Dimensional break stuff! And as much as full-scale aviation writer, discussed scale model errors on a one-tenth-scale model destructive testing is pretty cool, it’s structural testing in his May/June 1988 will be ten times larger in the full- also expensive and time consuming. I’d Sailplane Homebuilder’s Association scale model, whereas such errors on prefer to break some coupons or scale article, “The Lesson of Tehachapi and a a half-scale model will only be twice models, if possible. New Slant on Structural Testing” (p 236 as large. And since lambda is often So, scale model testing can provide in The Collected Works of Stan Hall, squared or cubed, such errors can meaningful results with considerably Vol I). If scale testing interests you, I significantly affect the results. Larger

52 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes scale models will also be easier to Scaling Factors source materials for and will probably be easier to construct than smaller Scale Model Parameter Scaling Factor models with fiddly details. Half- or Length Prototype/ λ quarter-scale (i.e., lambda = 2 or 4) seems to be a good compromise. Area Prototype/ λ2 • The scale factor lambda (λ) is estab- Volume/weight Prototype/ λ3 lished geometrically and factored according to the parameter being Test load, pounds or Newtons Prototype/ λ2 tested. Hall provides the scaling fac- Test loading, psf or Nm2 Same as prototype tors as seen in the table to the right. Torque Prototype/ λ3 Modeling a Wing Spar The wing spar of the SR-1 raceplane Angular deflection (from scaled torque) Same as prototype uses pultruded carbon fiber rods for its Linear deflection Prototype/ λ cap strips. I generally try to avoid rein- venting the wheel, and the pultruded Harmonic (vibration) frequency Prototype x λ carbon spar is a wheel that has already λ = Prototype linear dimensions/Model linear dimensions been worked out. Jim Marske’s work with the Genesis sailplane helped intro- test a scale spar for deflection (non- was a rod sized .118 inch x .019 inch duce pultrusions to the Experimental destructive) and load (destructive/to (0.002242 inch2). Spar cap strength is aircraft arena, and more recently Bob failure), followed by a static test to limit proportional to spar cap cross-sectional Kuykendall has successfully used pul- load of the real wing later. Since I had area, so we will use area as the scaling trusions in the spar caps of his HP-24 already calculated the dimensions of the factor. From the table, we know that sailplane, for example. real spar, scaling was easy. Goodwinds model area (.002242) = full-size area Although pultruded carbon has been Composites offered to sponsor the SR-1 (.02024) / λ2, giving λ = 3.00 (i.e., coin- used in sailplane wings, for whatever Project with pultruded carbon for both cidentally exactly one-third scale). reason they are not as common in pow- the scale spar and real spar. A one-third scale model is not a bad ered planes. Since a certain amount of The first step is to determine lambda. size. But remember that we are doing a engineering comfort is derived from While you can arbitrarily set a scale fac- test to failure, which means we will load knowing that a particular material or tor of one-fifth, one-quarter, etc., there the spar to ultimate load. The SR-1 spar design is common practice, the relative is nothing that says you need to scale is sized for a 700-pound aircraft (which lack of pultruded carbon (as compared to a whole number. In fact it may be translates to an approximately 600- to unidirectional fabric, which is more easier to use the relative dimensions of pound spar load since the weight of the common for making cap strips) pushed your materials (both full size and scale) wing does not figure in spar loading) me to want to confirm my spar design to govern the scaling. For example, the at 8 G with a safety factor of 2, giving and construction methods. Although SR-1 spar uses a .220 x .092 (0.02024 a total design load of 600 x 8 x 2 = 9600 I considered building and testing to inch2) rectangular pultrusion. The pounds. From the table, we know that failure a full-scale spar, I decided to most convenient pultrusion for scaling scale load is inversely proportional to

(Left) Comparison of pultruded carbon used in the full-sized spar with that used in the scale spar. Using a scale factor of 4.25 allowed one small stick to represent exactly two full-sized sticks, making the spar schedule easy to calculate. (Right) Cap strip weight was 0.49 ounce per upper and lower cap. A total of 0.98 ounce of pultruded carbon fiber was able to support almost 10,000 times its own weight.

Photos and Graphs: Eric Stewart KITPLANES August 2017 53 (Left) Box spar wrapped with shear web and awaiting cap strips. The blue foam “wings” will be wrapped with bias carbon to provide support for the weights, while the steel bars support the spar during testing. (Right) The support wings wrapped in carbon and peel ply. The carbon wings add nothing to the bending strength of the scale wing since the elastic modulus of bias woven carbon is far lower than that of pultruded carbon.

λ2, so 9600 pounds / λ2 = 1063 pounds. strips. Blue foam “wings” were hot- Testing the Model This was a bit more weight than I wired and attached to each side of the Load was applied 2 G at a time and wanted to deal with. However, using box beam to provide a surface onto recorded from a pointer at the wingtip a scale factor of λ = 4.25 allowed us to which weights could be stacked. Steel that slid against a ruler. (The reason for use exactly 1 small pultrusion for every rods pass through the spar where the not using the steel support rods is that 2 large pultrusions (convenient), with a wing attach bolts go on the full-scale the mathematical model used for load max load of 532 pounds. This was more spar and support the spar during test- deflection assumes a central pivot point.) to my liking. ing. The spar caps were then epoxied Unfortunately, when we pinned the Once lambda was determined, it to the top and bottom of the box spar. left end of the spar, we forgot to place a was easy to determine the dimensions Finally, the “wings” were wrapped shim under the weights to prevent the of the scale spar box, shear web, and in bias carbon and the scale spar was pin weights from touching the spar. number of spar cap strips since these ready for testing. Therefore, a certain amount of the pin had already been calculated for the Before failure testing, we wanted weight is resting on the left side of the full-scale spar. A spar box beam was to calculate deflection. This involved spar, counteracting the deflection at the hotwired from blue foam and wrapped “pinning” one end of the spar and right end and not acting as a true point in bias carbon fiber that represented applying a load to the other half, with load. This caused the measured deflec- the shear web. Since the primary goal a pivot point located under the center. tion to be somewhat less than what it of this test was to confirm the perfor- A 1-inch Delrin rod was used for the really should be. Also, due to the rela- mance of the pultruded cap strips, we pivot; the Delrin is hard enough not tively small amount of area upon which used more shear web than was strictly to deform but has just enough give to to stack weights, the load distribution necessary in order to ensure that the avoid presenting a sharp point load to is only an approximation of the actual shear web did not fail before the cap the spar surface. elliptical distribution one would see on the real wing in flight. The graph illustrates predicted vs. observed deflec- The finished spar ready for testing. tion. Predicted deflection has been approximated using the conjugate beam method, which is beyond the scope of this article but is discussed in most aircraft structure analysis texts. Once deflection testing was finished, it was time to load the spar to failure. This simply required stacking weights on the spar in a fashion that represented the loading on the real wing per the scaling factor. The Delrin rod was removed and the wing allowed to rest on the steel pins. It is important to measure your scale model before testing to ensure that it is indeed to scale. If the scaling is off, that is OK, but make sure this is reflected

54 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes (Left) Deflection testing. The white 1-inch Delrin rod under the center point of the spar acts as a pivot. The pinning weights on the left end should only be touching the very end of the spar. Since a certain amount of pinning weight is resting on the spar itself and counteracting the load on the right, the measured deflection is lower than it should theoretically be. (Right) Deflection per unit load is marked on the ruler. A quarter-inch slab of scrap high-density tooling foam (beige color) is taped to the top of the spar to avoid point loads. in your calculations. For example, the The spar held 600 pounds, and was Acknowledgments: Many thanks to model spar came out somewhat oversize. subsequently loaded with 620 pounds. SR-1 Project sponsor Goodwinds Com- Recalculating max load based on actual It held this weight for 7 seconds before posites for supplying the pultruded spar dimensions showed max load failing (a successful failure test requires carbon rods for both the SR-1 actual would be 640 pounds (versus the origi- holding the load for at least 3 seconds and scale wing spar pultrusions. More nal 532 pounds). Failing to recalculate before failure). The ultimate load was info on pultruded carbon rods can be would have given the impression that thus 620 pounds, or 97% of the pre- found at www.goodwinds.com. More the spar was stronger than it really was. dicted value of 640 pounds. The data info on designing spars with pultruded As can be seen in the picture above, sheet performance figures for this par- carbon can be found at www.ihpa.ie/ a set of stabilizing blocks was located ticular pultrusion thus proved accurate carbon-dragon/index.php/home-top/ about one-quarter inch under the left for this model, and our method of articles/83-graphlite-carbon-rod. “wing.” The left wing was loaded with construction validated. A video of the Eric St Eric weights and would deflect downward scale spar test can be seen at the SR-1 Eric Stewart is designing until it just rested on the blocks. The Project Facebook page: (www.facebook. and building the SR-1, right wing was then loaded with an com/TheSR1Project). a speed plane for setting equivalent amount of weight and also records in the FAI c-1a/0 had a block of foam located about 2 Summary category (takeoff weight less inches beneath it to catch the wing Like coupons, scale model testing offers than 661 pounds, including when it failed. This hopefully avoids an excellent way to hone your skills in e pilot and fuel). You can see weights and/or model parts being flung preparation for building the real thing, wart violently around when the spar breaks. as well as gain some insight into the more at www.facebook.com/ After each load was applied, the strength of your design. In next month’s TheSR1Project, including left blocks would be lowered another article, we’ll finally get to some fabrica- additional photos and videos one-quarter inch or so. This pattern tion techniques, starting with a simple of the subjects in this series was repeated, with approximately 40 flat sandwich panel, then work our way of articles. pounds of weight being added per time. up to molded parts. J

Predicted (blue) vs. observed (red) deflection. Observed deflection is Failure occurred in compression just outboard of a less than actual due to error induced by improper pinning of the spar reduction in the spar cap cross-sectional area. The bias during testing. “wing” skin has been peeled away to inspect the break.

KITPLANES August 2017 55 Home Shop Machinist Tube bender Model 3. Mechanics from aviation’s golden age did a lot of DIY tube bending. To be qualified for field repairs on factory-built “ships,” one had to know how to lay out patterns, make custom forms, and torch heat tubes red hot so they could be pulled around a bending form by hand. Today, when you encounter a bent or formed tube as part of a design, it’s often supplied pre-formed, or, if not, the bending is kept as simple as possible so the builder can get the job done with basic tools and techniques. The WW-I replica kits from Airdrome Aeroplanes are a good example. The Conrad Norquist shows how the 6061 tubes supplied with Airdrome Aeroplanes kits are easily bent using wood templates aluminum fuselage and tail feather tubes are easily bent by hand using ply- The JD Model 3 sells for around $300, can pick and choose the ones you need wood templates. minus dies. It is a manual version of the and add to your collection as you go. The wood block method is not so hot hydraulic-powered tube bender that is The Model 3 uses a lever and ratchet- when it comes to tighter bends and steel used in countless race car and custom ing system to generate the torque to tubing, particularly 4130 chrome-moly. welding shops. It does not include a drive the forming die around the pres- For that, you need a die-form bender stand, but if you’re bending tubes, you sure die and bend the tube. Each throw like the Model 3 tube bender made by can probably weld your own. The die of the lever adds only a few degrees of JD Squared of Tennessee. The Model sets run between $130 to $400 depend- bend, so it’s easy to achieve a precise 3 has been around for years and has ing on the size tubing and radius you angle. Every tube has some amount proven to be superior to hydraulic pipe want. Each set includes a forming die, of springback, which means the elas- benders or roller-type tubing benders. a pressure die, and a holding strap. You tic properties of the tube won’t allow it

This stripped-down sequence shows how the forming die is driven clockwise against the pressure die to create the desired bend, in this case a 180.

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

56 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes to exactly match the die or the degree wheel. To compensate for springback, you have to slightly overshoot the target angle. How much depends on the size, strength, and thickness of the tubing you’re trying to bend. According to JD, 4130 will spring back twice as much as the same thickness mild steel tubing. Template and pattern bending can be a challenge, but using the Model 3 simplifies the task because it’s easy to gauge where each bend starts. By working from the center out, per the tutorial provided by JD (see their website: www.jd2.com), you can make highly accurate runs. The biggest challenge to tube bend- The lever and ratchet drive on the Model 3 bender makes it easy to account for springback. ing is preventing kinks and wrinkles. To get a 90-degree bend in this section of 7/8-inch diameter x 0.049-wall 4130 required going to 98 degrees. These can occur when the bend radius is too small, the tube is too thin, the material is too soft, or any combination of these factors. You can eliminate, or at least minimize, these distortions by providing some sort of internal support. Production shops use a ball or bullet- shaped mandrel tethered inside the tube between the forming die and the pressure die. The home shop method is to pack the inside of the tube with something that will provide enough support to resist the forces trying to squish the tube. Horn makers have been known to fill tubes with water and freeze them. Another method is to use a low- temperature solder-like metal called Cerrobend. The obvious drawback to freezing is the time and space required to plug and freeze large or long pieces of By marking where the tube lines up with the forming die, you can accurately gauge where tubing. Cerrobend is only slightly more your bends will form for any particular tube size and wall thickness. practical. Although it melts at a low temperature (about 160° F), that’s still hot enough to really burn (don’t ask), and you need a decent ladle and fun- nel to get it in the tube. A more practical solution is to simply pack the tube with sand. As the photos show, sand packing significantly improved the results when making a 3-inch radius, 90-degree bend in 7/8-OD x 0.049-inch wall 4130 tubing. The Model 3 tube bender is a solid addition to any shop that plans to do even a modest amount of tube bending. I find that having one changes the way I design parts because tube bending is fast and easy, and usually looks more elegant than a cut and welded joint. Using a torpedo level simplifies the orientation of the second bend perpendicular to the first.

Photos: Bob Hadley KITPLANES August 2017 57 (Left) Dry bending a 90-degree, 3-inch radius in 7/8 x 0.049-inch 4130 resulted in significant squishing (from 0.875 to 0.705 inch). Lubricating the pressure die helped a little, but the tube still deformed significantly (0.770). Only after filling with sand (right) did I finally achieve a decent result.

To be sure, the Model 3 is not the only way to bend a tube. Heating and bending around a custom form (along with sand packing) might turn out to be the only way to get a bend that doesn’t con- form to an off-the-shelf bending die. Regular and long-time readers might recall the March 2014 issue, which featured my visit to the EAA Kermit Weeks hangar. Master machinist and fabricator Bauken Noack was faced with recreating seat frames for a group of 1920-era Ford Tri-Motors that are still in service. His solution was a shop-built tube bender using a cable pulley as a pressure die/fol- lower die. As you can see from the pho- (Left) With the bottom end capped with a steel plug tack-welded in place, the sand is packed tos, it’s ingeniously simple and it works. as tightly as possible using a ram and a dead blow hammer or, even better, a 10-ton hydraulic You can’t beat that! J press. (Right) Once the sand is compacted, tack weld a plug on the open end.

EAA master fabricator Bauken Noack shows off his custom tubing bender for fabricating Ford Tri-Motor seat frames. (Photos: Lori Farenholtz)

58 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes

BEST PRACTICES Electrical, part 2. Last month we looked at the best panel. There should be no circuits with- for a short period of time, we do not need materials to use to wire your plane and out breakers except for the starter main to size the alternator to cover them. That examined the topic of grounding. This power, and no doubling up of circuits leaves us with a total continuous load of time I want to start out with the equip- on one breaker. That is why we want to about 15.6 amps. ment list and then look at alternators list every single item on the equipment The basic rule for sizing the alterna- and overvoltage protection, starters, wir- list. With this list completed you can now tor is to have the total continuous load ing diagrams, circuit breakers and fuses. start to think about what materials you not be more that 80% of the alterna- Because the topic of aircraft electrical is will need to buy. tor’s rated capacity. Based on this, an so large, we will have to save a few items alternator with at least a 20-amp capac- for next time—batteries, backup sys- Alternators and ity would cover the load, but would not tems, and electrical circuits. Overvoltage Protection leave us with much extra to recharge a Again, I emphasize that this is merely If we add up all the current requirements battery depleted by extended cranking an introduction to the topic of aircraft from the equipment list, not counting at start-up. A B&C pad-mounted alter- electrical systems and refer you to the the alternator power, we get about 17.5 nator (BC410-H) that puts out about 30 publications mentioned last month— amps. However, we see that the starter amps at cruise engine rpm would be a Bob Nuckolls’ AeroElectric Connection, relay draws 1.9 amps, and it is what could good choice, or you could consider a Marc Ausman’s Aircraft Wiring Guide, and be called an intermittent load. Electric Plane-Power unit of similar size (FS1-14B). the FAA’s AC43.13-1B. flaps or electric landing gear motors If your total continuous load was more would be other examples of intermittent than about 24 but less than 32 amps, you The Equipment List loads. Since these loads are only present would need a 40-amp alternator. In every Before you start running wires and mak- Voltage Max. Current Breaker Weight ing connections, you need to make an Item Location equipment list: a list of every electrically Volts DC Amps Amps Pounds powered item in your plane, its required Dynon D180 10-30 2.0 3 2.75 Panel voltage, location, and current draw. You PS Eng. PM1200 13.8-27.5 0.2 1 0.75 Panel may wish to list the weight of each item, too, but that is optional. Once you have Garmin 496 11-35 1.2 2 1.0 Panel an equipment list, you can determine Garmin SL40 10-40 2.2 3 2.75 Panel wire sizes and circuit breakers or fuses. Garmin GTX 327 14-28 1.9 3 3.1 Panel Below is an equipment list for a very simple airplane, but the same principles AeroLED strobes 9-36 2.25 3 0.5 Wings apply to more complex installations. Alternator power 14 40 50 6.1 Engine Note that every item has its own breaker. Fuses can also be used, but Alternator field 14 4 varies 5 — Engine more on that later. The main point is Starter relay 12 1.9 3 0.9 Engine that every item gets its own breaker, and Master relay 14 1.9 3 0.9 Engine every circuit will begin at the breaker

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 so far completed three—a GlaStar, a Glasair Sportsman, and a Texas Sport Cub—and is helping a friend build an RV-8. When he isn’t building some- Dave Prizio thing, he shares his love of aviation with others by flying Young Eagles or volunteering as an EAA Technical Counselor. He is also an A&P mechanic, Designated Airworthiness Representative (DAR), and a member of the EAA Homebuilt Aircraft Council.

60 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes case, be sure to get an alternator with enough capacity, but don’t get carried away. Too much capacity just means too much weight, and weight is always the enemy in an airplane. Alternators come with internal and external voltage regulation and overvoltage protection. In general Plane- Power units have internal voltage regulators, and most have internal overvoltage protection. On the other hand, B&C alternators rely on external voltage regulators and overvoltage protection. The Plane-Power approach makes for a simpler installation at a lower cost, but the B&C approach seems to be more robust because it removes the voltage regulator from the heat of the engine compartment. They are both popular The Plane-Power alternator shown here has become very popular with amateur airplane choices with Experimental builders. builders. Its internal voltage regulator and overvoltage protection make it very easy to install. This one is going into an RV-8. Always be sure to ask about overvoltage protection. Most manufacturers are used to go before everyone got rid of of that enjoyed by Sky-Tec, which is now including it as standard now, but you vacuum-powered gyros. This eliminates owned by Hartzell. They make an ultra- want to be sure. Voltage spikes can kill the belt drive typically found on larger lightweight starter that only weighs 6.25 expensive avionics, and overvoltage pro- alternators, and it saves several ounces of pounds, their standard and very popular tection is cheap. If your system doesn’t weight. However, if you need 40 amps or LS series that comes in at 8.25 pounds, have it built in, be sure to add it. B&C more capacity, you will need to go to the and the KPS series that weighs about 8.9 makes an overvoltage protection mod- belt-driven unit of the appropriate size. pounds, and includes kickback protection. ule that you can buy for around $68. If The pad-mount alternator can be added As for what is the best practice when you don’t have this protection by some to a larger system as a backup. it comes to starters, there is no hard and other means, this is a sound investment fast rule. It depends on what is impor- for the protection it offers. It might save Starters tant to you. If robustness and reliability you thousands of dollars someday. Experimental aircraft with Lycoming- are paramount, a heavier starter with If you don’t need more than 30 amps type engines come with Sky-Tec starters things like kickback protection may best of capacity in your charging system, a more often than any other brand by a meet your needs. If the absolute mini- pad-mounted unit is worth your con- wide margin. B&C and Hartzell (Hartzell mum weight is more important, then sideration. These attach to the back of Engine Technologies) also make fine the ultralight Sky-Tec starter is made for the engine where the vacuum pump products, but their sales are only a fraction you. Most people split the difference and go with something like the Sky-Tec LS-series starter. When purchasing a starter there is more to it than weight and price. Lycoming makes two different types of ring gears, one with 122 teeth and one with 149 teeth. It is very important that you get a starter that is matched to the number of teeth you have. To find out what is on your This B&C voltage regulator has become the gold standard for Experimental engine, you can count the teeth or just airplane electrical systems. It has built-in look at the shape of the teeth. B&C and Plane-Power now both make overvoltage protection. On the downside Because of the high current draw of alternators that attach to the back of a it is more expensive and more compli- the starter motor, it is always activated Lycoming-type engine where the vacuum cated to wire than the Plane-Power system by means of a starter relay or solenoid. pump used to go. They are a good solu- where everything is contained within the tion for people who do not need more alternator. On the positive side, it is less That way only a small current needs to than 30 amps total alternator capacity or vulnerable to the heat and vibration of be switched to turn on the starter. If not for those who want a backup alternator. the engine compartment. for this, the starter switch would have to

Photos: Dave Prizio KITPLANES August 2017 61 deal with 200-300 amps and would be huge. The starter relay differs from the master relay in two ways. One, it need not be rated for continuous use. And two, it is switched with positive power. The power wires in and out of the starter relay are the big 2- or 4-gauge wires. The relay is activated with a 20-gauge wire from the starter switch. The relay must also be grounded. Just remember that the starter and master relays are different, and try not to get them mixed up. It is good practice to install a diode between the two small posts of the starter relay to extend the life of the Typical installation of the master and starter relays in an RV-8 under construction. Note relay. Similarly, a diode can help extend how the starter relay is mounted upside down to prevent it from being accidentally activated during aerobatics. the life of the master relay if placed between the activation wire (negative) Schematics tend to be rather abstract, airplane. It will be your job to bring those and the hot (positive) side of the relay. using electrical symbols that you can find wires to the other side of the connector Any 1N5400 or 1N4000 series diode can in AC43.13-1B or any number of electrical and make them line up with the pre- be used and should be connected so the handbooks. Their weakness is that they wired connector provided. To do that cathode end (end with silver stripe) is don’t usually depict the actual location you must know the pin location for each toward the positive terminal. of items, but merely show how they are wire you are bringing to the connector. As a side note, if you plan to do aero- connected together conceptually. The pin-out diagram shows you that batics with your new plane, it is better A more pictorial wiring diagram will information. The only hard part is work- to mount the starter relay upside down. typically show where items are in the ing with those annoying D-sub pins and That way high positive G’s will not acci- plane and will often use symbols or getting them in the correct holes. dentally activate the starter relay. images that are more like the actual Whenever you have multi-pin connec- parts involved. These drawings tend to tors, the pin-out diagram will be your best Wiring Diagrams be larger, but that can be managed by friend if you ever have to go back and fix Wiring diagrams come in many forms breaking them down into sections. or modify something. Without it you are from schematics to more pictorial wiring If you have a pre-wired instrument up a creek without a paddle, as the saying diagrams to simple pin-out diagrams. panel from someone such as SteinAir or goes. Be sure to keep these somewhere Each has its function. The important Aerotronics, you will most likely get what handy after you complete your project. thing is to create a wiring diagram that are called pin-out diagrams. These pan- The best practice in this regard is to will work for you if you, or someone else, els come with pre-wired Cannon plugs make up a wiring diagram as you go, and ever needs to go back into your electrical or other multi-pin connectors that then then clean it up when you are finished. system and change or repair something. must connect to the various items in the Keep it along with any schematics and pin-out diagrams you might have in a safe place for future reference. Along with these things you should retain any literature that came with any electrical item in your plane. Try to put it all in a big notebook if you can. You will be glad you did down the road.

Circuit Protection For years Bob Nuckolls has been advocat- ing for the use of fuses instead of aircraft circuit breakers for circuit protection. At first almost everyone dismissed that as a crazy idea, but with the introduc- This simple pin-out diagram furnished by Aerotronics with one of their panels shows where wires go in the plug that the builder must make up to mate with the one coming tion of the Van’s RV-12, his idea finally out of their instrument panel. These diagrams make it easy to know where to connect each got the respect it deserves. Fuses save wire in your electrical system without referring to more complex and abstract schematics. money and weight, and who doesn’t

62 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes The Van’s RV-12 was an early adopter of the fuse idea pioneered and promoted by Bob Nuckolls. This subpanel shows how this idea can easily be integrated into a modern instrument panel. want to save money and weight when goes to each device needing electrical they are building an airplane? That said, power. A ground wire then comes back the urge to use aircraft circuit break- from that device to ground, preferably a ers is so ingrained in most of us that it ground bus. There are no fuses or break- is almost irresistible. But, come to think ers on the ground side of the circuit. The of it, how many times have you actually same size of wire is used coming and reset a circuit breaker in flight? And if you going. The total length of the wire for Traditional circuit breakers still have many did, how long did it stay reset? In truth, size calculations needs to consider the fans in the aviation world. Even though if a fuse blows or a breaker trips, there is entire round-trip length. they are more expensive and heavier than something wrong that needs to be fixed Breakers or fuses are powered from fuses, there is no denying that it is easier to reset a breaker than look for and install that isn’t going to magically repair itself a bus. This can be a bar with a number a new fuse. by resetting a breaker or replacing a fuse. of holes that line up with the powered In any case, if you do decide to use fuses, (line) sides of a row of breakers or fuses, avionics without requiring each unit to you will need to carry some spares that or it can be simply a set of wires that be switched on separately, or an essen- can be readily accessed in flight. You will loop together to the powered sides tial bus that makes it easy to shed non- need enough of each size to replace half of those breakers or fuses. The master essential items in case of an alternator the number of that size, with a minimum relay sends power to the bus and thus failure. This isn’t anything complicated. of one of each size. provides the breakers or fuses with posi- It is just a group of breakers or fuses that The important thing to remember tive electrical power. Oftentimes break- are powered together and connected is that each circuit begins with a fuse ers or fuses are grouped into sub-buses, to the main bus through a relay that or breaker. From there the power wire such as an avionics bus that turns on all switches them as a group. Getting back to fuses and breakers, they are there to protect the wire going to the various devices. That means that a breaker or fuse should never be so large as to allow a wire to overheat in case of a short. It is always permissible, but rarely best practice, to use an oversized wire. It is never permissible to use a breaker or fuse that is oversized for the wire being used. There is much more to look at next month. In the meantime, check out some of the very helpful EAA Hints for Homebuilders that deal with electrical Here is the backside of a circuit breaker panel, along with a number of switches. If you look closely, you can see the bus bar that ties the line side of the circuit breakers together. issues, or many others for that matter. Lacing bundles of wire together keeps things neat and helps prevent chafing and Here is where you can find the electrical unwanted movement. hints: http://tinyurl.com/kpkzaqo. J

KITPLANES August 2017 63 CHECKPOINTS Fun in cold weather. As I write this column it is 18° F in down, usually in the middle of January, they would open, and then preheating Atlanta. Unfortunately, by the time you’re the days are nice and clear, albeit bone- the engine with a torpedo heater actu- reading it, most of us will be sweltering in numbing cold at times. Thank good- ally exceeded the flight time. But I was summer heat, probably at Oshkosh. But ness for the line boys, who usually took having fun. hopefully, some of these thoughts and care of all the preheating needs of the I started to think about creative ways ideas will help you get prepared for next aircraft. Most of us looked like Ralphie’s to shave time off of the whole process, winter. I know there are many of you who brother in Christmas Story though, as we and realized if I could somehow keep the probably even think 18° is balmy, but learned that the cockpit heaters really engine warm, that would help quite a for this transplanted Clevelander living didn’t function very well at those temps, bit. Don’t forget that this was in the time in Atlanta, it feels downright cold! See- especially on the ground while warming before internet and cell phones, so there ing as I just saw an article from Russian up the engine. Couple that with the need wasn’t a way to remotely turn on heaters. scientists that we are perhaps entering to keep the doors open to prevent the Most of the programmable timers I could another Ice Age, chances are it will be windshield from fogging and icing on find would only work on a daily cycle, even colder next winter. the inside; the prop blast into the cockpit and at the time my flying was mostly Yes, we moved from Cleveland to was really quite miserable. But, we were limited to weekends, so I didn’t want to Atlanta over 25 years ago due to a job having fun! preheat the engine every day. I finally change at Hewlett Packard. My future figured out that a 60-watt light bulb in boss (and now a longtime best friend) Winter Ops With an RV-4 a trouble light tucked up underneath had me come to Atlanta for the inter- When I finally finished my RV-4 on Christ- the cowling through the exhaust exit, view on a nice, sunny day in April. To mas Eve in 1983, we ended up moving coupled with a nice big blanket over the this day I still believe he checked the it to the airport during an unforecast cowling, always managed to keep the weather forecast before inviting me snowstorm. That was the beginning of engine above freezing no matter what down on a particular date. But really, my foray into cold weather ops with my the outside temps were. No more wait- there was no challenge, as we probably own airplane. I discovered that there was ing for preheat! hadn’t seen the sun in months in Cleve- now a requirement for a different set of The other thing I learned quickly was land by April anyway! equipment that needed to be packed in to preheat the seat cushion in my car by Those of us who are really immersed in the car in order to go flying. See, I quickly leaving the car running and the heater aviation don’t often let the elements get learned that it made no sense to keep on full while I shoveled the snow. After in the way. In the late ’70s and early ’80s, the snow shovel and snowblower in the a while I finally remembered to just take when I was flight instructing part-time in hangar the first time I drove to the air- the cushions with me and leave them in Cleveland, aviation was really hopping port and saw the three-foot snowdrifts the car. The cushions were made of tem- and we were busy. If you weren’t flying, blocking the entrance! I had to borrow per foam, which at normal temps is really you weren’t being paid. Unfortunately, the equipment to now get to mine. So, nice and comfortable. But below freez- there is a big body of water called Lake I learned to keep them in the car after ing, they were like a brick! The front one Erie that has a very large impact upon the that episode. I also learned to add some wouldn’t even compress enough for me early winter weather. It is a huge mois- extra time to the allotted time to go fly- to close the canopy unless I preheated it. ture generator, and until it cools off or ing, as sometimes just extricating the Of course, the cockpit heater was freezes over, you can count on wet snow, airplane from the snowbound hangar, totally worthless, and it is still hard to icing, and low ceilings. Once it cools chipping the ice away from the doors so forget the numbing cold prop blast in

Vic is a Commercial Pilot and CFII with ASMEL/ASES ratings, an A&P, DAR, and EAA Technical Advisor and Flight Counselor. Passionately involved in aviation for over 39 years, he has built 10 award-winning aircraft and has logged over 8000 hours in 70 different kinds of aircraft. Vic Vic Syracuse had a career in technology as a senior-level executive and volunteers as a Young Eagle pilot and Angel Flight pilot. He also has his own sport aviation business called Base Leg Aviation.

64 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes my face from having to keep the tip-over canopy open while taxiing to prevent fogging the interior. I never did figure out a good solution for that one other than a ski mask, which I wasn’t fond of due to the viewing restrictions it imposed. Taxi- ing at an airport down narrow and newly plowed taxiways with a very-low-wing airplane such as an RV-4 was a real challenge. Unfortunately, during those years of excessive snowfall, there was nothing to do except wait for warmer weather to decrease the height of the snowbanks. Many times I walked the length of the taxiways with a snow shovel to knock down the highest peaks of the snowbanks. Then, of course, I sat in the car for a while to thaw out! Fun has different You know it’s cold when you’re watching hundreds of guys on Minnesota’s Centerville meanings to each of us, doesn’t it? Lake from your plane—fishing! (Photo: Pete Howell) I also soon learned to regularly check tire pressures on warmer days, as these today will be gone by tomorrow instead The hangar doors were frozen shut with were prior to the Leakguard tubes we of next month like Cleveland), I still prac- ice, along with about four feet of ice in have today. Another lesson that turned tice some of the lessons learned. front of the hangar. We managed to get out OK was to stay off of the brakes as I preheat the engine whenever the the doors open using a shovel to break much as possible during taxiing, not outside temps are in the low ’40s or up the ice, and then pulled the aircraft that they did much good on the ice- lower. Why? Well, the oil temp comes up out of the hangar with a rope and a four- covered taxiway anyway. The heat from much faster, making for shorter engine wheel-drive truck. the brakes melted the snow, but if the warm-up time, which helps to eliminate I still do look forward to a cold season runup took too long, they cooled back lead buildup on plugs and valve guides. in Atlanta, although I’m happier when it down and would freeze stuck! It was a The 60-watt light bulb is no longer is not too cold and doesn’t last too long. balancing act to try to get the tailwheel needed, as I like to use the E-Z Heat stick- Two reasons—there isn’t a need to do airplane rolling again without nosing on oil pan heaters. I plug it in the night a weight and balance after every land- it over. Once I had the left brake freeze before a flight, still covering the cowling ing due to bugs, because there aren’t tight in flight, only to realize it upon with a blanket, and the whole engine and any in the winter. Second, after flying landing. I thought for sure I was headed oil is at 100 degrees the next morning. I all summer in the heat and commensu- into the snowbank with disastrous even use them on the remote oil sump of rate higher density altitudes, it is really results when it finally broke free. Rotax engines with the same result. nice to experience the climb rates of the I have learned one thing to be care- RV-10 in the colder air. Sometimes they Moving South ful about when it comes to moving the are over 2000 feet per minute, and the One of the happier days of my life was airplane out from a hangar that is at 50+ air is so clear that we joke about being when we moved to Atlanta, and I gave degrees into 18-degree air outside. The able to see into the middle of next week! my snowblower to my father-in-law. It rapid cooling of some parts can cause The heater design in the RV-10 is super was a win for both of us as we were both problems, such as canopy cracks in any powerful, and coupled with the heated very happy. Perhaps he was happy I was stressed areas. There is nothing like the seats, we are able to fly in comfortable leaving, but I attributed it to him getting loud POP of a canopy crack as you are shirts and pants, with the cold weather a nice snowblower. pulling it shut to remind you that you survival gear on the back seats in case of One of the first things I noticed after should have been more careful. Tough an unplanned, off-field landing. Dressing moving to Atlanta was that my flying lesson learned. like Ralphie’s brother is a distant memory. hours doubled in the first year! Yep. I was reminded this week of how much I had to fly to Missouri last week to do Weather was no longer the big factor as I don’t miss chipping away at the ice and a prebuy inspection on another RV. The it was in Cleveland. Plus, since moving to snow to go flying. The north side of OAT was 16° F at KTBN when I landed. I Atlanta, we’ve always either had the air- Atlanta actually had 3–5 inches of snow quickly covered the engine with a blanket, plane at home in the garage (Kitfox) or in over the weekend, and I had to go to a blocking the air inlets in order to keep the the hangar at our home. While the temps north-side airport Monday morning to engine warm. I sure enjoyed the depar- aren’t nearly as cold (the 18 degrees here fly with a new RV-10 owner. Guess what? ture in those temps. That was fun! J

Photo: Pete Howell KITPLANES August 2017 65 Increasing gross weight, adding IFR to operating limitations, transponder requirements. By Mel Asberry

Question: I’d like to increase the gross weight is based on G loading and applicable requirements of Part 91. All maximum gross weight of my E/A-B will be lower than the aircraft’s normal maintenance or inspection of this equip- PA-11 clone. I just completed the gross weight. ment must be recorded in the aircraft 40-hour Phase I test period, and I Yes, you will need to place the aircraft maintenance records and include the am operating the plane as an LSA back into Phase I and perform new test- following items: date, work performed, with a maximum gross weight of ing to the new gross weight. Since you and name and certificate number of per- 1320 pounds. I built the aircraft will essentially have to test all parame- son returning aircraft to service.” with PA-18 landing gear, so I am ters to the new weight, I seriously doubt If your operating limitations do not confident it will handle an increase that you will be able to do it in 5 hours. include the above paragraph, you can to 1650 pounds. The 5 hours listed in your operating lim- have them amended. An Aviation Safety If I change the maximum gross itations is a minimum. Inspector (ASI) or any DAR holding weight, will I have to go back into Question: My RV-12 ELSA inspec- function codes 33 and 47 can amend Phase I and fly off an additional 5 tion was done by the FAA. My oper- your operating limitations. hours? Nothing has been changed ation limitations restrict me to VFR Question: I’m finishing building on the aircraft since the DAR sign- and do not allow a path to upgrade an Experimental Cub with a 20-amp off. I am an A&P with years of avia- the plane to IFR in Phase II. I would alternator. I’m not planning any tion experience but not so much in like to get my operating limitations flights in controlled airspace and the Experimental area. I hope you updated to allow IFR. Is this pos- will be staying under 2500 feet agl. can advise me. sible? If it is, can you also point me Will the DAR want me to install a Answer: You may increase the gross to the place in the FARs that says I’m transponder? weight of your Amateur-Built aircraft. allowed to do this? Answer: The requirement for a tran- You should have engineering data to jus- Answer: Operating limitations are sponder is a flight issue, not a certifi- tify the ability of the aircraft to handle in FAA Order 8130.2H, Appendix C. cation issue. If you have an electrical the new gross weight. You mentioned It takes a bit of patience to get through system, you will need a transponder to that you built the aircraft with PA-18 them if you are not familiar. The para- fly in certain controlled airspace. There’s landing gear; I’m sure you are aware that graph you are looking for is in Table C-1, no requirement for a transponder the landing gear is not the only limit- #41. It applies to 21.191(i). and states: regarding aircraft certification. J ing factor of gross weight. Also, if the “Instrument flight operations are aircraft is certificated for aerobatics, you authorized if the instruments specified Please send your questions for DAR will need to establish a new aerobatic in § 91.205(d) are installed, operational, Asberry to [email protected] with gross weight. Normally the aerobatic and maintained in accordance with the “Ask the DAR” in the subject line.

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KITPLANES August 2017 71 Verticality. We’ve had about half a dozen highly is to reroute the coax coming from the why will always be their boss. (Harry technical articles in a row now. It is about antenna elements. Somers, thanks for that advice.) time to do some of the easy stuff that you What that means, in essence, is that OK then, let’s get started with the can do without much sweat. we are going to complicate the mechan- l-o-n-g explanation. Way back in KITPLANES® history [May icals and simplify the electricals. Instead We start with the speed of both light 1997], I showed you how to make a vertical of routing the coax out the bottom of and radio waves: 186,411 miles per sec- antenna with a matching coil on the bot- the antenna, on the other side of the ond or 300,000,000 meters per second, tom to decouple the coax shield from the wooden element mounting rod, I’m your choice. All my measuring sticks are antenna elements. The problem with that going to take it at right angles from the in “English” (as opposed to metric), so I design is that the antenna had elements center of the antenna, run it out a rea- want to eventually come up with inches capable of receiving/transmitting from sonable distance, and then put on the for my lengths. I can do it either way, but one end of the com band to the other, connector to the outside world. to do it neatly, I’m going to have to use but was limited to some rather closely I could do a little hand waving, give some conventions and algebra that we spaced frequencies by the resonance of you some plug-in formulas to calculate learned in high school. Wait, wait, I’m the matching coil. I’ve been waiting for 20 lengths and such, and that would prob- not going to lose you in esoteric math. I years to rectify that little problem, and I ably let 90% of you make this little gem promise. Just remember that 102 = 100, think I’ve got a Weir two-fer winner. without any trouble at all. My particular 103 = 1000, 104 = 10,000 and so on. Let’s The coil was there to take care of the problem with that is that as a profes- convert those speeds above into inches radiation of the bottom element into sional teacher, I’ve only given you 10% of and into the powers of 10 that we saw the coax coming down the other side the knowledge that lets you understand above. Remembering that a mile is 5280 of that wooden element mounting rod. not only the how, but the why. I got some feet and that one foot equals 12 inches, I’ve been pondering this limitation for a very good advice from my first boss at we can say that the speed of light in Eng- while, and have come to the conclusion PSA (Pacific Southwest Airlines) who told lish is 186,411 * 5280 * 12 = 1,181,106,432 (no use rushing things after 20 years) that me that (s)he who knows how will always inches per second. In our little exam- the only way to take care of the problem have a job, but the person that knows ple above, that can be represented as

The wooden dowel with copper tape affixed and the coax cable The mast mount PVC Tee fitting and two short lengths of ½-inch attached to the copper tape. PVC pipe.

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

72 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Connecting the coax to the ½-inch end The BNC connector assembled into the Using a short length of RG-174 coax to space cap BNC connector. end cap and attached to the coax pipe the wooden antenna element rod to keep with a ½-inch ell fitting. the rod from wiggling around in the pipe. 11,811*10 6 inches/second. (The current the dead center of the aviation com band. say, 123 MHz, your wavelength would be shorthand for this is 11811E6.) Pick your own “favorite” frequency for the 96 inches (11811E6/123E6). If we convert the metric measurement, best response from your antenna. And, in Now for an easy cheat. Forget the and knowing that a meter is 39.37 inches, our mathspeak from the last paragraph, powers of 10 (“E6”). Since the E6 terms we come up with the speed of light this is 127*106 or 127E6 MHz. cancel out if our frequency is in mega- as 11811*10 6 inches per second. Wow, Now we know how fast the radio wave hertz (MHz) the shortcut is: wavelength = exactly the same number. is going and how many times it vibrates 11811 / frequency. Now we ask ourselves if an electromag- per second. We ought to be able to calcu- Pretty easy, eh? Now I can tell you netic wave (“signal”) vibrates, oh, just for late how far that radio wave goes in one that 127 MHz antennas are theoretically example, 127 million times a second (127 “cycle” or one vibration. We call this a made from quarter-wavelength ele- million = 127 mega; 127 mega cycles per “wavelength.” Pretty easy. Speed divided ments. Divide wavelength by four and second is 127 megacycles, or in modern by frequency is how far a radio wave now you know that a quarter wave is terms, 127 megahertz [generally abbrevi- goes in one cycle: 11811E6 / 127E6 = 93 23.25 inches. Theoretically. ated 127 MHz]). Did I pick 127 MHz for some inches. You want to slant the center fre- We now depart the science of antenna magic reason? Nope, just the frequency in quency closer to the low end of the band, design for the art. The first thing we

The completely assembled antenna.

Schematic: Jim Weir KITPLANES August 2017 73 The antenna painted and ready to install. The ½-inch mounting mast shown here was later replaced with ¾-inch Schedule 40 PVC water pipe for greater strength. have to contend with is what is called and you get a “dielectric foreshortening” “end effect,” which shortensany rea- as a function of the thickness of the PVC sonable diameter (say, larger than #30 relative to the diameter of the antenna. wire) antenna element 5% right off the You can’t calculate this shortening eas- crack of the bat. Multiply 95% by 23.25 ily, but by measurement we find that it inches, which gives us an antenna cut is roughly 1% for the pipe we are using down to 22.1 inches. (see below), so the absolute last final Now we have to worry about “fat- length of the copper tape is 1% less than ness” of the antenna elements. If you are 21.6 inches or a final length of the copper making this antenna from #14 Romex tape of 21.4 inches. wire, you don’t have to worry. If you So, here we go with a quick explana- want fatness, you can get copper tape tion of the mechanical assembly. It turns from hobby craft stores (Ben Franklin, out that 3/8-inch wooden dowel just Hobby Lobby, etc.) to go up to half- exactly fits into ½-inch Schedule 40 PVC inch-wide elements. You shorten the water pipe. The images with this article element 1% for each 1% of the fatness pretty well explain how to assemble the versus the length. For example, for half- PVC pipe into an antenna. inch tape, you divide half an inch by the One last “Rev. B” and we are done for foreshortened length of 22.1 inches (0.5 the month. I originally intended to use / 22.1 = 2.3%). Shortening the 22.1-inch ½-inch pipe throughout the project. It copper tape still further by 2.3% gives turns out that this was just a little too 21.6 inches as the tape length for each flimsy for the mounting mast, so I did a ear of the dipole. ½-inch to ¾-inch transition for the ¾-inch What do you gain by fatness? Band- Schedule 40 mounting mast. width. That is, your antenna is good Oh, the Weir two-fer? Simply rotate (a purely subjective parameter) over a the antenna mast fitting and the con- wider range of frequencies. Romex may nector fitting 90 degrees and you have be good for a couple of megahertz either a horizontal nav antenna if you recal- side of center frequency. Half-inch tape is culate the copper tape length for your good for about 8–10 Mhz either side of nav frequency. center frequency. This is one of the “easy” construction One last “shortening.” We are going articles. More to come in future articles… to put this antenna into PVC water pipe, Until then…stay tuned… J

74 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes Gyroplanes, part 3. For the last few months we have attitude indirectly, by aiming the rotor The stability and control characteris- been looking at gyroplanes. This month thrust. The attitude and pitch accelera- tics of a “modern” gyroplane configura- we turn our attention to pitch stability tion of the body will be determined by tion that is controlled by aiming the rotor and control. the orientation of the RTV relative to the thrust are quite different than those of a In flight, a gyroplane is suspended center of gravity (CG) of the body, the classical autogiro. This is particularly true by the upward thrust of its autorotating aerodynamic forces acting on the body for the Bensen-style machines with no rotor. As we discussed last month, the itself as a result of its shape and angle horizontal tail. rotor blades can flap or teeter, and accord- of attack, and the thrust vector of the The analysis that follows is a signifi- ingly, the rotor cannot transmit a moment engine and propeller. cantly simplified look at the quasi-static directly to the mast through the shaft. This is a significant difference from pitch trim and stability of a gyroplane. The stick commands the angle of the early autogiros. Before the advent of It neglects the effects of detailed rotor rotor plane of rotation relative to the direct control of the rotor, autogiros dynamics and blade flapping, but is suffi- body of the gyroplane. By positioning were controlled in pitch by airplane- ciently accurate to illustrate some impor- the stick, the pilot determines the direc- style elevators on the horizontal tail. The tant phenomena. tion of rotor thrust vector (RTV). orientation of the rotor axis of rotation, Initially, we will consider a gyroplane For the purposes of this article, I am and hence the rotor’s plane of rotation with no horizontal tail and the engine/ defining the “body” of the gyroplane relative to the rest of the gyro, was fixed. propeller thrust line oriented directly as everything hanging from the rotor. This arrangement worked well as long as through the center of gravity to remove The body of a typical gyroplane has there was a significant forward airspeed, thrust-induced effects. To further sim- no aerodynamic controls, and the pilot but gave very little control at low air- plify the analysis, the body is assumed therefore is only controlling the body speeds and in steep, slow descents. to generate no aerodynamic pitching moment and to have neutral aerodynamic pitch stability without the rotor.

Trim In order for the vehicle to be in trim, the sum of all of the moments acting about the CG must be zero. In our simplified gyroplane, the weight acts downwards through the CG, and the rotor thrust acts on the mast in a direction normal to the rotor plane of rotation. In order for the vehicle to be in trim, the rotor must be oriented so the RTV passes through the CG. The steady-state orientation of the rotor in level flight will be tilted backwards relative to the direction of flight to produce a positive angle of attack on the rotor disk. Because of Like a classic Bensen-style machine, this “modern” gyroplane has no horizontal tail. this, the CG of the body will be somewhat

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

Photos: Barnaby Wainfan KITPLANES August 2017 75 forward of the mast so that the line from the rotor hub to the CG is normal to the rotor disc at cruise. In steady-state trimmed flight, the RTV passes directly through the CG. If the rotor is tilted back further, so the RTV passes ahead of the CG, there will be a net nose-up moment causing the nose to accelerate upwards, and if the rotor is tilted back less, there will be a net nose-down moment, and the nose will pitch down. The effect of this is illustrated in Figure 1, which shows the pitching moment of our example gyroplane at three different rotor tilt angles (rotor incidence) as a function of body angle of attack. Look first at the line for 7.13 degrees rotor incidence. This is the rotor orientation at which the vehicle is in trim. The Figure 1: With 7.13 degrees rotor incidence, the gyro is in trim. When the incidence is 9.13, CG has been placed far enough forward the nose is pointed up, and with an incidence of 5.13, the nose is down. of the mast to put the machine in trim with the body at zero angle of attack stable in pitch. It has no aerodynamic and holding it. The RTV is now tilted in cruise. The 7.13-degree angle is the tendency to return to its original angle of more forward and passes behind the tilt-back angle that a relatively efficient attack if perturbed by a gust or a control CG. There is a net nose-down pitching rotor (rotor L/D=8) will have when flown input. The 7.13-degree rotor incidence moment that increases in magnitude at its best L/D. plot in Figure 1 illustrates this. Changing with increasing angle of attack. This The net pitching moment is zero at vehicle angle of attack does not produce is stable, but the gyro is out of trim zero body angle of attack as intended. any change in pitching moment. nose-down as long as there is positive Importantly, it is also zero at all other We now turn our attention to the two (upward) rotor thrust. In upright posi- angles of attack. This is because, unlike a other lines on Figure 1. These represent tive-G flight, the gyro will pitch down wing, a rotor generates its net force nor- the situation with the rotor tilted +2 at an ever-increasing rate with the stick mal to the plane of rotation so the RTV and –2 degrees respectively from the held in this position. In this linearized rotates with the vehicle as pitch attitude trimmed setting. analysis, there is a stable trim point at changes, and its direction relative to the Looking first at the upper curve, we zero rotor thrust, but this is not achiev- CG therefore does not change with vehi- see the result of the pilot pulling the able in the real world since the rotor rpm cle angle of attack. stick aft to tilt the rotor back and raise will decay and the rotor will become This is a crucial difference between the nose. The RTV will now be rotated aft unstable in flapping long before this a gyroplane and a trike. The lift of a relative to the rotor head, so it passes in zero-G condition is reached. wing acts essentially normal to the front of the CG. Notice that at all angles airstream. As angle of attack changes, of attack, there is a net nose-up pitch- Implications even though the drag changes, the ing moment. Also, the magnitude of The implications of these characteristics net resultant force vector of the wing the moment increases with increas- on longitudinal flying qualities are pro- remains close to the same orientation ing angle of attack. These two effects found. On a stable airplane the pilot is normal to the airstream. As the trike mean that the aircraft has a net nose-up commanding angle of attack with the pitches nose up, for example, the center moment and is also unstable in pitch. If stick. If the airplane is flying in a trimmed of gravity moves forward relative to the the pilot holds the stick in this position, steady-state condition and the pilot lift vector, which produces a stabilizing the gyroplane will pitch nose up at an wants to fly slower, the stick is pulled aft moment driving the nose back down. ever-increasing rate. It will not find a new to a new position and held there. The On a gyroplane, the rotor thrust vector trimmed equilibrium at a higher angle of airplane will respond by pitching up, rotates with the vehicle, and no stabiliz- attack and slower airspeed with the stick and settling down in a trimmed condi- ing moment is produced. fixed in this position. tion at a higher angle of attack. To fly What this means is that an ideal tail- Looking at the bottom curve we see faster, the stick is pushed forward, and less gyroplane flying in trim is neutrally the effect of pushing the stick forward again, the airplane responds by pitching

76 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes down to its new trimmed angle of attack pilot who does not understand the If the pilot’s responses fall behind the and stabilizing there. The trimmed posi- difference will likely end up overcon- actions of the gyro, the combination of tion of the stick moves steadily back as trolling and chasing the pitch attitude the gyro’s characteristics and the pilot’s trimmed airspeed decreases, and each when transitioning into the gyro. inputs will lead to a pitch oscillation that stick position uniquely trims the air- Second, as airspeed increases, the can quickly diverge to the point where, plane at a specific angle of attack. mount of pitch acceleration com- at the nose-down extreme of the oscil- None of this is true for the gyroplane. manded by a given stick motion will lation, the rotor blades flap down far The pilot of a fixed-wing airplane or increase proportional to airspeed enough to hit the tail or the propeller, a trike is commanding a trimmed angle squared. This means that the pitch leading to catastrophe. of attack with the position of the stick or control will rapidly get more sensitive It’s easy to see how a pilot with little control bar. as airspeed increases. A machine that gyro experience, or a pilot exploring The pilot of the gyroplane is com- responds relatively slowly in slow flight higher flight speed than he has flown manding a pitch acceleration with the will respond much more quickly in before, can get into trouble quickly. stick. The gyroplane is only in trim at cruise. As the pitch sensitivity increases, So far, we have only considered an ide- the single stick position where the the speed of the pilot’s response to any alized machine with no tail, and the thrust RTV is going directly through the CG. pitch rate must increase accordingly, line passing through CG. Next month we At this position, the net moment is and it will become increasingly difficult will begin to explore how other configu- zero and the pilot is not commanding for the pilot to keep up. ration features affect flying qualities.J any pitching motion. Since the gyro is neutrally stable, if there is any pitch rate when the stick is at the trimmed position, the pitch rate will continue. To stop it, the pilot must tilt the rotor to create an opposing pitch acceleration and then move the stick back to the trimmed position when the pitch rate goes to zero. Changing airspeed in a gyro is a multi-step process. The pilot must first move the stick in the direction of the desired pitch attitude change. This will cause the gyro to develop an ever-increasing pitch rate. As the nose approaches the desired attitude, the stick must be moved in the opposite direction, past the trim position to generate an opposite pitch acceleration to stop the pitch rate. As the pitch rate comes to zero (ideally at the desired attitude) the pilot must move the stick to the trimmed position to capture the attitude. ...and leave your engine In flight, the pilot will be moving the stick continuously in a series of small monitoring to EIS. inputs, first one way and then the other, Trusted with everything from 2-strokes to keep the pitch rate near zero and to turbines for over two decades. hold attitude. Since the gyro is neutrally stable, pitch rates will not die off by themselves, and the pilot will be called on to actively augment pitch stability at FLY IT all times. like you stole it... There are several ways this can lead to trouble. First, a fixed-wing pilot’s instincts do www.grtavionics.com • (616) 245-7700 not apply to a gyroplane. A fixed-wing Proud sponsor of Tiger Airshows and airplane “thief” extraordinaire, Hotwire Harry!

KITPLANES August 2017 77 REAR COCKPIT The most necessary thing in aviation. Somewhere in flight training we all powers remain well in the background. So there you are considering probably came across that well-known graphic People employed in deprecation of grav- the most elemental force of flight: a rea- of the genero-plane with four arrows ity for a living, especially those wear- son to fly. I’ve found it about the most around it. “The Forces of Flight,” it’s typi- ing uniforms in flight, are typically so necessary item not on the checklist. It’s cally titled and, of course, there is the cocooned by support structures such as something that can slip away if you’re obligatory “Thrust, Drag, Lift, and Grav- ground crew, fuelers, dispatchers, and not careful. ity” called out. It’s all so neat and easy to the comforting counsel of chief pilots The AOPA folks handling the Rusty understand, like curling up on the sofa and commanding officers that little time Pilot seminars no doubt have more and having NOVA take us on a precisely can be spent contemplating either the insight on this than anyone, but ulti- one-hour tour of Antarctica. Without so romance or physics of flight. They have a mately each of us has to identify their much discomfort as grabbing ice cubes job to do, after all. own motivation and recall it when the from the freezer tray in that hour, we But for those of us either past get- spirit flags. After all, has there ever been sense a complete understanding of the ting paid to fly or having never had a time when you sort of pushed yourself world’s under-curve, right down to how the chance, there comes a time when to get up in the air and later thought it a penguin rookeries must smell. the new wears off, and the thought of bad idea? It’s rare. Usually we’re out of the flight school tugging open the hangar doors and If our flight motivations are personal, nest and into the more nuanced real wheeling out the air buggy sounds, if as plane builders and owners, there are world when we learn the actual forces not a little like work, then an activity not forces working against our will to fly that acting on the pilot, if not the plane, are without effort. are at least partially in our control. After money, FAA, dreams, and reality. This “Where should I fly to?” becomes the 400 hours in a truly fun, but in some ways realization is held in such high esteem it’s question. Or more succinctly, “Why?” challenging, very homebuilt airplane, printed on T-shirts and paraded to the The weather is good, the evening winds I’ve vowed that should I get the chance masses by people spending their own calm, the day’s work done, and there to rebuild my current mount or build a dollars to act in an educational capac- you are with an airplane but maybe new plane, there are a few things I will ity—a well-appreciated effort, for sure. feeling a little tired and probably a bit more highly value. But after flying for a while, there comes guilty for it. After all, you invested all First of these is comfort. I’m just as drawn the nagging suspicion there may be that time and money into the machine; to ground and aerial hot rods as ever, but other forces in play. For some these other your family sacrificed so you could after 45 years of squeezing, bending and justify that leather jacket, literally aching for my fun, I’ve had it. If it and now you’re having hurts to sit in your plane, it can become trouble coming up with a reason not to fly that day. If you’re con- the mental oomph to get templating building a certain design, down to the airport and make sure you fit first (fighters and racers commit some aviation. are exempted)! And along those lines, at What would you tell Leon- 6 feet 2 I’ve found it less than informative ardo da Vinci or the Wright to speak to 6-foot-0-inch people about fit. brothers should they be Fractions of an inch count, as does wiggle standing there? You’re not room after wearing a five-point harness in the mood? for 20 minutes. If you’re already building

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 August 2017 www.kitplanes.com & www.facebook.com/kitplanes a plane, try to keep the totality of the fin- tandem ships are often lacking storage. service loop installed. I wasn’t happy with ished cockpit in mind. Tacking stuff to Wing lockers, under-seat space, and introducing a bunch of new solder joints the bottom of the panel is easy to do, but (carefully considered) aft-fuselage access in my electrical system, and I shouldn’t can be space-killing. are a few solutions. Many pockets and have had to. The original builder should Baggage space has also moved up my sleeves around the cockpit help as well. have put in enough wire for servicing. list. Admittedly, I’m flying a tandem-seat, Serviceability is another will-do item Likewise, nutplates may knot your open-cockpit bird with room for a tooth- for me. Many homebuilts, especially windsock when building, but lord, you’ll brush if you zip-tie it to the engine’s oil legacy designs assembled by die-hard love them come the first condition fill tube—and yes, I’ve seen the owner of fiscal fist clenchers, simply don’t account inspection. Fumbling with little nuts and the sister plane to mine thread a banjo for having to maintain them. These cats washers is for watchmakers. between his torso and the fuselage, then use just enough to get the job done and Then there is the general environment fly across two western states, but that’s can’t be bothered with niceties such as around your plane. If the airport is 30 not my tune. Small spaces add up, so if access panels. You know you’re going to miles away…if the hangar doors are too you can find a cubby, turn it into a stor- lube control bearings, or at least want to heavy or balky…if you have to move two age locker. The boss put a pair of lockers eyeball them and their mounts for cracks, airplanes to get your airplane out…if it in his RV-3’s engine cheeks, which frees so why entomb them behind acres of takes a half hour to uncover all the pro- the sparse interior from having to carry doped Dacron? Next time I think I’ll put a tective canvas over your sits-outside air- the oil rag and fuel checker, which, if zipper in the aft fuselage. plane each time you simply want to chase nothing else, helps subdue the mechani- Even more common, there’s no sav- a sunset, you probably won’t chase it. cal aroma in the cockpit and helps when ings in not building in ease of mainte- In short, if you’re building an airplane, headed over the horizon for a few days nance now. When the ignition switch my advice is to make it as user friendly and you’re looking to squeeze in a banjo. failed on my bird, we quickly found—of as possible. If it costs a knot or two in Side-by-side airplanes are usually not course—there was no service loop in speed, or horrors, makes a bump in the baggage challenged as their weight-and- the wires, and it was nearly impossible to finish, that’s a small price for making balance characteristics favor steamer- take the old switch out, much less install something you’ll want to use, rather trunk storage behind the front seats, but a new one. So all the wires were cut and a than force yourself to fly.J Kitplanes subscriber alert! several of our Kitplanes subscribers have received what appear to be “renewal notices” or “automatic renewal notices” from a company known as preMier subscriptiOn serVice, 5star subscriptiOns, rapiD MaGaZine cOllectiOn, MaGaZine billinG serVices, publisHer’s billinG serVices, circulatiOn billinG center or other similar names. Addresses for these firms include Dallas, tX; lincoln, ne; Omaha, ne; san luis Obispo, ca; salt lake city, ut; White city, Or and prescott, Fl. These firms have nOt been authorized by us to sell subscriptions or renewals for Kitplanes and we cannOt Guarantee that any order or payment sent to them will be forwarded to us. Kitplanes does nOt offer a subscription term of more than 2 years, nor do we retain your bank account information. if you see an offer for 3 or more years or if you receive a notice that references your subscription anD your banking information, it is nOt an authorized offer. We urge you to report these notices to us, as well as to your state’s attorney General and better business bureau. any offer you receive that does not bear our company logo or corporate/customer service address or 800 numbers should not be considered approved by us. the only autHOriZeD inFOrMatiOn for Kitplanes is: toll free via telephone 1-800-622-1065, Dial america renewal telemarketing, or www.kitplanes.com/cs Our texas customer service center: 1-800-622-1065, pO box 8535, big sandy tX 75755 Or our corporate offices at: belvoir Media Group, llc. aviation publishing Group 535 connecticut ave norwalk ct 06854 should you have any questions at all about mail that you receive, please contact us at our website: www.kitplanes.com/cs or call us toll free to speak to customer service.

Illustration: Robrucha KITPLANES August 2017 79 By Robrucha

80 KITPLANES August 2017 www.kitplanes.com & www.facebook.com/kitplanes