A Gyroplane 1 • Starter Troubleshooting • Wheel Alignment • Building Three Guys and a Bearhawk a Bearhawk the Journey Begins LSA

Get A GRIP! WHAT’S ON YOUR STICK? KITPLANES

MAY

2014

® Vortex M912 Gyroplane • Get Vortex a Grip • Cowling

Heat M912 Shields Low and Slow in • Panel

Upgrades a Gyroplane 1 • Starter Troubleshooting • Wheel Alignment • Building Three Guys and a Bearhawk a Bearhawk The Journey Begins LSA

Shields Up! Protect Your Cowl MAY 2014

BELVOIR From the Heat

PUBLICATIONS IN THE SHOP Hun in the Sun Still Fighting the • Panel Upgrades Great War • Starter Troubleshooting

• Wheel Alignment 101 www.kitplanes.com

May 2014 | Volume 31, Number 5 Reader Review 6 Vortex M912 Gyroplane: Low, slow…and fun! By Karl Storjohann. Builder Spotlight 14 Buildin g the Bearhawk LSA: The start of a long, enjoyable tale. By Ken Scott. 18 Get a Grip! Choices in the stick grip market. By Tom Wilson. 26 HeAt sHields: Protecting your cowling from excess heat. By Eric Stewart. 14 31 hoW THE PROS DO IT: Jim Kimball Enterprises—building the better biplane. By Dan Horton. 36 Straight and Narrow: Wheel alignment 101. By Dave Forster. 42 error Chain: First flight surprise! Canopy—closed and latched? By Mike Newall. 44 a ll About Avionics: Panel upgrades—planning the project. By Stein Bruch. 73 Ask the DAR: Operating limitations, selling a homebuilt, aircraft that can’t be registered. By Mel Asberry. Shop Talk 48 Maintenance Matters: Look beyond the starter motor to solve starting problems. By Dave Prizio. 55 Home Shop Machinist: DIY safety wire drilling. By Bob Hadley. 58 p ractical Electrical: Battery facts and fables for the aircraft builder—part 2. By Robert L. Nuckolls, III. 77 Aero ’lectrics: The ultimate ground plane. By Jim Weir. Designer’s Notebook 74 Wind TunneL: Aeroelasticity II—aileron flutter. By Barnaby Wainfan. Exploring 6 2 editor’s Log: Eye’s on. By Paul Dye. 5 What’s New: Strut camera mount from Aircraft Spruce. By KITPLANES® staff. 61 the Dawn Patrol: Fun with the Hun in the sun. By Dick Starks. Kit Bits 4 Letters 67 list of Advertisers 68 Builders’ Marketplace 80 kit StufF: Drawing on experience. By cartoonist Robrucha.

61 On the cover: Karl Storjohann on short final in his Vortex M912 gyroplane. Photographed by Cindy Peters at Hay Springs Municipal Airport in Nebraska.

KITPLANES May 2014 1 Editor’s log Eyes on. “Just be careful in there Mr. Dye— hands-on airplane building and mainte- a person nervous and afraid. But this those boron struts are each worth more nance experience, I was a shoe-in for the inspection party was more of a celebra- than your annual salary!” visit. And I never passed up an opportu- tion—a coming out with a challenge by At the time, I was peering through the nity to visit the Mojave. the builder: please, find the flaws in my hatch into the internal wing structure of The inspection was like any other project! He was open and honest about Rockwell Orbital Vehicle #105—soon to airplane inspection—you look for fit the fact that he wanted help, and not be known as Space Shuttle Endeavour— and finish, acceptable cable and tubing afraid to take criticism and critical com- and getting ready to crawl inside to do retention, safety wire—all of the things ments about his work. a pre-delivery airframe inspection. The that make the craft airworthy. Obvi- Truth be told, it was one of the nic- technician helping me get ready to enter ously, the men who built it felt it was up est building jobs I have seen in all my the wing wanted to make sure I under- to snuff, or they never would have let us years of working on airplanes and being stood just how important it was to watch in the building—but even then, the air- a tech counselor. When a builder takes my step. The struts in question—very frame began collecting a myriad of col- the time to lay the flat EGT wires against thin-walled cylinders with attachment ored Post-it notes highlighting areas we each other in a perfectly rectangular points on each end—actually formed wanted addressed. This wasn’t a knock bundle, you know he has paid attention the structure of the wing “ribs” and were against anyone—it just sometimes takes to details. easily damaged if you weren’t careful in a fresh set of eyes to spot anomalies that Yet as good as it was, there were at moving about. Summoning up the skills have become familiar to those too close least a dozen things that other builders I learned as a cave explorer in my youth to the project. found that the owner needed to look at. (“damage nothing” was the motto), I All of this was on my mind recently as I I personally found only one thing that I crawled into the wing with my flashlight slowed down to enter the pattern at San thought needed careful attention, and in my mouth and hoped not to tear my Martin/South County Airport in Santa that is the point of having multiple “eyes white bunny suit. Clara County, California. The builder of on” the target plane—everyone will find The purpose of this “management a soon-to-be-flying RV-7 had advertised something different. Inspection” was to determine if the air- an “airplane inspection party,” inviting Don’t be afraid to let others find the frame was in a condition good enough builders who were interested to come flaws in your work; the truth is, anyone for NASA to accept it from the contractor and pick apart his work before calling for competent enough to find your mistakes who was building it in Palmdale, Califor- the DAR to come for a licensing visit. Hav- and omissions has made countless num- nia. If it passed muster, it would then be ing a large number of experienced build- bers of their own. It’s how we all learned. shipped to the Kennedy Space Center in ers and opinionated pilots (are there any Take the inspection to heart and realize Florida for final finishing and equipment other kind?) drop in to dissect your many that you are probably just inches from installation before its first flight in about years of careful work takes intestinal the finish line—take your time, analyze two years. NASA assembled a group of fortitude of the highest order—and it the comments, and fix what needs to senior engineers with management cre- shows a commitment to honest, open be fixed. dentials for this two-day trip to the high risk management that should be our Whether you’re building a Cub or a desert to fill a square on the checklist to standard in the Experimental world. space shuttle, everything is open to scru- that first flight, and since I was one of Inspections can be like check rides or tiny—it’s how we keep each other alive the few folks on the prospective list with a test in school: something that makes to fly another day.J Paul Dye 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 currently flies an RV-8 that he built in 2005 Paul Dye and an RV-3 that he recently completed with his pilot wife. A commercially licensed pilot, he has logged over 4500 hours in many different types of aircraft. When not writing on aviation topics, he consults and collaborates in aerospace operations and flight testing projects.

2 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes At just $4,375*, it won’t cost you a wing and a tail.

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17442 G3X Lower Price Ad-KitPlanes.indd 1 5/7/13 7:45 AM EDITORIAL Editor-in-Chief paul Dye [email protected] UL Power Update column than I did in four years of aero- Managing Editor mark Schrimmer nautical engineering school. Keep up the Art Direction Dan Maher Although we strive for 100% accuracy, Editorial Director paul Bertorelli we do make occasional errors. In our great work. Contributing Editors larry Anglisano, Roy Beisswenger, March 2014 issue, the table on page 27 Peter Kuykendall chuck Berthe, LeRoy Cook, robert Hadley, Dan Horton, for UL Power engines was inadvertently ed Kolano, Amy Laboda, Rick scrambled. We regret the mistake and Dick Stark Responds: Just about every- lindstrom, Dave Martin, Robert nuckolls, Dave Prizio, Doug have published the correct table below. where we go, we are made aware that rozendaal, Dean Sigler, Dick We thank the many readers and UL our planes are not authentic. You know starks, Eric Stewart, Barnaby Power who brought this error to our what? We don’t care. We’re there to have Wainfan, Jim Weir, Tom Wilson. Webmaster Omar Filipovic attention.—Ed. fun and spread the word that “Joe Nor- Cartoonist Robrucha mal” can build a real warbird (well, Horsepower Price Model Weight kinda) for the price of a decent used car. ADVERTISING Range Range Sr. Advertising Manager chuck Preston The kids we put in the planes at airshows 805/382-3363 UL260i 97 158 $19,000 [email protected] don’t seem to care much about authen- UL260iS 107 158 $20,000 ticity either; they’re just glad to get the BUSINESS OFFICE Belvoir Media Group, LLC UL350i 118 172 $24,000 chance to sit in an airplane their size. 800 Connecticut Avenue UL350iS 130 172 $25,000 (F-18 and F-15 pilots get a real charge Norwalk, CT 06854 out of sitting in them, too!) EDITORIAL OFFICE UL390i 140 220 $29,000 We have no intention of ever trying P.O. Box 1295 UL390iS 160 220 $30,000 Dayton, NV, 89403 wing warping. And we have never consid- 832/851-6665 UL520i 180 238 $34,000 ered using the narrow, thin, ultra-skinny [email protected] UL520iS 196 238 $35,000 original airfoils. As you mention—and CIRCULATION from reports we have seen—they have Circulation Manager Laura McMann Prices fluctuate with euro/dollar exchange rate and are set on date of purchase. absolutely horrifying flight characteris- SUBSCRIPTION DEPARTMENT tics. Remember rule one: fly safe! 800/622-1065 www.kitplanes.com/cs P.O. Box 8535, Big Sandy, TX 75755-8535 Dawn Patrol Hirth Engines Stocked For Canada: Box 7820 STN Main, London, ON N5Y5W1 I love vintage aeroplanes and think it’s in USA BACK ISSUES fantastic that someone is keeping that In the March 2014 Engine Buyer’s Guide, P.O. Box 22251 spirit alive. But the fat airfoil on the you mentioned that Hirth Engines are Beachwood, OH 44122-2251 800/571-1555 Airdrome Aeroplanes makes me cringe only available from Germany and take www.kitplanes.com/backissues every time I see it. I can forgive the fact 4 to 6 weeks for delivery. This is not cor- REPRINTS FOR PUBLICATION that a fuselage might be a bit wide to fit a rect. Engines are ordered from within the AND WEB POSTING AVAILABLE VW engine, or that replicas of the Taube USA, not Germany, and we have engines Minimum Order: 500 and Eindecker aren’t wing-warpers, but in stock in Ohio for immediate delivery. Contact Jennifer Jimolka, 203/857-3144 that glaring thick airfoil looks like a fat Matt Dander Change of address? lip on a pretty model. I know that the Recreational Power Engineering Missing issue? period-correct airfoil had ugly pitching U.S. Distributor, Hirth Engines Subscription Question? moment issues, and worse stall charac- www.recpower.com Visit www.kitplanes.com/cs. teristics, but isn’t there a modern (safe) Or call 800/622-1065 from the U.S. and Canada. airfoil that looks more the part? Thank you for bringing the correct infor- I really enjoy the magazine. I think I’ve mation to our attention. We apologize for Foreign 903/636-1112 or fax learned more from Barnaby Wainfain’s 203/857-3100. the error.—Ed. J

Back Issues: Call 800/571-1555 Web site 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, 800 Connecticut Avenue, Norwalk, CT 06854-1631, 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 ©2013 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 call 800/622-1065. Kitplanes® is a registered trademark of Aviation Publishing Group, LLC.

4 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Strut Camera Mount from Aircraft Spruce With the proliferation of small video cameras between the wingstrut configuration to the and the Internet making it easy to distribute tubular configuration takes seconds. The pat- and share videos, many builders and pilots are ented attachment method ensures that the looking for unique ways to mount their units in mount will not mar or damage the wingstrut or and outside their aircraft. Nothing is more dis- tube it is attached to while providing a very solid turbing than wondering if that expensive cam- point of attachment. The mount is machined era you stuck to the wing with duct tape will be from proprietary 6061 aluminum extrusions there when you land! specifically designed for this product. The cam- The new Strut Camera Mount from Aircraft era mounts to a 1/4-20 stud attached to the pro- Spruce was specifically designed to mount fessional ball mount, which gives freedom of industry-standard action cameras to the wing- movement to set up the shot as needed (camera strut on Cessna Aircraft including the 150, 152, 170, 172, 180, forward, rearward, or sideways). The ball mount is very rigid, 182, and 210. Experimental aircraft utilizing Cessna wingstruts and it acts as a vibration-minimizing attachment between the can also use this Strut Camera Mount. In addition, the mount camera and the mounting surface. can also be reconfigured to attach to tubular structures between For more information (including aircraft applications), 1.13 and 2.80 inches in diameter—making it adaptable to please visit www.aircraftspruce.com or contact Aircraft Spruce almost any aircraft with a roll bar in the cockpit. Switching at 1-877-477-7823. Find a direct link at www.kitplanes.com. J

To submit a press release on a homebuilt-related product, email a detailed description and high-resolution photograph to [email protected]. Mailing address is KITPLANES®, New Products, P.O. Box 1295, Dayton, NV 89403. Your submission may be used in print or online at www.kitplanes.com.

KITPLANES May 2014 5 Vortex M912

Low, slow... and fun! By Karl Storjohann

6 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes The kit comes well-packaged in sturdy crates. The Vortex kit is extremely complete and well organized—individual small parts are shrink-wrapped on cards and easily identified.

After a very steep approach, the The gyroplane is not affected by wind flight instruction to their customers, gyroplane flared just above the grass and nearly as much as a fixed-wing aircraft which is extremely important. If you gently settled to the surface without any because of the high wing loading (rotor want a long life, do not train yourself. landing roll. That really got my atten- loading), which takes you through the The Vortex M912 is a completely tion. The pilot then spun up the rotor, thermals without the big bumps. redesigned Vortex model that came applied power, and departed in about The wind always blows in my part about while Sport Copter was design- 100 feet of ground roll. Impressive, since of the country, so being able to handle ing a gyroplane that could handle I have spent the last forty years modify- wind is important to me. Landing into the rough use dished out by Austra- ing Cessna airplanes, trying to achieve the wind with zero ground roll is the lian ranchers. To accomplish this, very short takeoffs and landings with clincher. I was hooked, especially when I the Vortex M912 is designed with a good results, but nothing that short. realized that I could get into a gyroplane state-of-the-art suspension system. It This took place “down on the farm” at for under $60,000. That is a lot cheaper has 11 inches of travel and rate-sens- Oshkosh several years ago, and it made than a helicopter. ing shocks with heavy-duty springs enough of an impression that it became that can handle fast rates of descent my next project. My Choice for Off-Roading with safe recovery. The tail boom is The gyroplane is a rotary wing air- Talking to knowledgeable people in extended to place the horizontal sta- craft, but not a helicopter, since it does the rotary-wing community lead me to bilizer farther back to handle the not power the rotor and thus cannot Sport Copter of Scappoose, Oregon. extra torque from the 100-horsepower hover. The rotor is powered by the air Their kit is extremely well designed and Rotax engine. The large rudder, plus traveling up through it, as it is always every part is powder coated or other- the large end plates on the horizontal tilted somewhat back as the gyro is wise protected from corrosion, making stabilizer provide great stability and propelled forward by a pusher engine. it a quality product. Also, they provide directional control.

The author hangs the new Rotax 912 on the frame of the gyro. The author attaching the long-stroke landing gear to the frame Building the gyro involves little fabrication—the majority of the of the gyro. work is assembly.

Photos: Karl Storjohann, Cindy Peters KITPLANES May 2014 7 Putting it Together The kit arrived in January. Unpack- ing shipping boxes revealed that all the small parts were shrink-wrapped on cardboard squares. Every bolt, nut, cot- ter key, washer and all small parts are all on these squares. The squares are marked to correspond with a page in the construction book. This book contains a lot of pictures that aid in understanding exactly how to assemble a part. The kit is all assembly, no fabrication, so it goes together very fast. I was concerned about meeting the 51-percent rule since the gyroplane kit is just assembly, so I downloaded the FAA checklist for determining compliance from the Popular Rotorcraft Association web site (www.pra.org). After filling it out, I knew I had easily built more than 51% of the kit, but I still felt the need to meet with the FAA district office to see if they agreed. It would not be a good day The instrument panel of the M912 is simple, but provides everything the author needs if they determined that I did not meet in a compact package. the rule, so I scheduled a face-to-face meeting. This turned out to be a good Training to Fly (called the cyclic) tilts the rotor to provide idea, if for no other reason than peace My Vortex gyroplane was basically com- control response the same as a like move- of mind. To my relief, they agreed that pleted by the middle of May, so I trav- ment in a fixed-wing aircraft. Pulling the according to my information, I met the eled to Scappoose, Oregon to get the stick back tilts the rotor back, thus you 51-percent rule and they would be glad training I needed to be a safe gyro pilot. go up. The rotor takes the place of the to do the airworthiness inspection. On arrival, I found out that being a long- elevator and ailerons. Preflight includes If a builder wants to build at the fac- time tailwheel pilot is a big help. Ten cleaning the rotor blades with rotor wash tory, they are happy to make that happen days later, I was on my way back home (a mixture of water and wax), in addition for a price. Doing this means that you will to finish the gyro and get it inspected. to checking the oil, water, and giving all never have to wait for missing parts and Flying the Vortex M912 is very much fasteners a good look. Then you mount will quickly be flying your own reasonably- like flying a fixed wing—but with a few up, strap in with seat belt and shoulder priced STOL gyroplane. very important differences. The stick straps, and release the rotor brake. Master

Part of the pre-flight ritual is to clean the bugs off the leading The gyro features a large windshield, but wide open sides keep edges of the rotor blades with a mixture of water and wax. you in constant touch with the air and your surroundings.

8 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Sport Copter president Jim Vanek adjusts the rotor tracking on Vanek checks blade tracking using a flashlight and reflectors the author’s M912 during a factory visit. mounted on the rotor tips. on, ignition switches on, choke applied, Getting Airborne is held full back, and within seconds, the then engage the start switch to bring the Once the engine is at operating tempera- nose wheel comes up. The stick goes for- Rotax to life. The throttle is not cracked ture, the prerotator is engaged at about ward a little to stop over-rotation, and off as that will not allow the choke to engage. 2000 engine rpm. The prerotator is oper- it flies. Level-off in ground effect to allow The 100-hp Rotax starts instantly, the ated by a belt on the prop shaft to a pulley the gyro to gain speed, and then start choke is slowly disengaged, and the on a flex shaft, which goes up the mast to the climb. At 4000 feet msl, the Vortex throttle is moved off the stop to secure a Bendix. When tension is applied to the climbs 700 feet per minute at 45 mph a fast idle. The two Bing carburetors on belt, the Bendix kicks in to engage the indicated. The process just described is the Rotax 912 are altitude compensated, ring gear on the rotor. The whole craft for a short/soft field takeoff technique which eliminates a mixture control. shakes as the belt slips to get rid of some that is used to depart from rough ground. Primary steering input is accomplished torque. Then, as the rotor gains speed, the by independent toe-operated hydraulic belt is tightened more and everything gets Cruising disc brakes. To taxi to takeoff position smooth. At 250 rotor rpm, the prerota- Level at cruising altitude (typically the requires light taps on the brakes because tor is disengaged, the power comes up to legal minimum), the power comes back the nosewheel is free castering. full, brakes are released, the cyclic (stick) to 5000 rpm (75%), which results in 60

KITPLANES May 2014 9 Vortex M912 Gyroplane Kit price (less engine)...... $38,495 Estimated completed price...... $66,350 Estimated build time...... 120 hours Number flying (at press time)...... 27 Powerplant...... Rotax 912 ULS, 100 hp @ 5800 rpm Propeller...... Warp Drive 68 inch, 3 blade

Airframe Rotor diameter...... Sport Rotors 8 in x 27 ft, ...... adjustable pitch Fuel capacity w/long-range tanks ...... 18.5 gal Maximum gross weight...... 934 lb Typical empty weight...... 565 lb Typical useful load w/full fuel...... 258 lb Seating capacity...... Single place

Performance The author installed a smaller radiator with louvers (here, partially closed) to replace the Cruise speed...... 80–95 mph large radiator that required duct tape to keep from over-cooling. Maximum speed...... 110 mph Minimum speed (continuous)...... 25 mph Maximum rate of climb ...... 700–1000 fpm open and that makes you feel very alive. Passing a junk pile, I have to circle to see Takeoff distance...... 10–100 ft Wind comes in from the open sides. A if there is anything that I could use. Low Landing distance ...... 0–10 ft slight vibration is felt coming from the and slow is a world of joy. Specifications are manufacturer’s numbers and are based on rotor, giving one the feeling that they the configuration of the demonstrator gyroplane. have a hold on a living machine. The Maneuvering mph showing on the airspeed indicator controls are not oversensitive. They feel Maneuvering flight really brings out and 350 rpm on the rotor tach—and just like a fixed-wing aircraft: not too the difference between fixed wing and I can start breathing again. Thewow light or too heavy. rotary wing. The gyro is very maneuver- factor is off the charts. Every powered Cruise flight (65mph) is slow enough able, requiring a fraction of the turn- parachute and trike pilot knows what to have plenty of time to look at every- around space of a fixed wing; still it has a I am referring to. In the Vortex, as thing on the ground—and I mean every- lot of drag with 27 feet of rotor spinning with many gyros, I am sitting behind thing. Passing an outhouse with an open as it is being pushed through the air, a windscreen, but very much out in the door, I see that it is occupied, so I wave. so it takes a while for increased power

Factory training is provided in a tandem, two-seat gyrocopter.

10 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes to make a performance difference. The gyroplane will not stall, but sure will go into a sink at too low rotor rpm. I do a vertical decent by taking the power off. The gyro descends straight down in a level attitude with full control, but full power and nose-down stick are needed to stop the sink before reaching the ground—failure to do so might hurt. The rotor does not care which direction it is going, so the gyro will turn around in a tiny space. It does take a lot of power to keep the rotor rpm from decaying too much during the turnaround. The 100 hp Rotax really helps. From a rotary wing pattern of 500 feet msl, you can land a gyroplane much like a fixed-wing aircraft by keeping some power all the way to the landing, but I prefer the no-roll landing since I land off airport. I do that by removing all the power and establishing a 45° nose-down angle while maintaining 45 mph. The gyro is flared just inches above the grass as the rotor is tilted back and becomes a big air brake. The forward momentum stops, the rotor is making the wump-wump sound, and the gyro settles to the surface. If the wind is blowing, the gyro will go back up if you don’t level the rotor after landing. Mod Time! After I’d flown the gyro for a year, I began to get concerned about the rough treatment it received from all the off- airport landings, so I decided to have the experts look it over at the factory. The excuse for such a long trip was a gathering of Cessna pilot friends who are meeting at McMinnville, OR (home of the Spruce Goose) the last weekend in June. A few days with good friends is vital for good mental health, so I removed the rotor, loaded the gyro into a van trailer, and headed out to Scap- poose, Oregon 10 days early. This would give me a week to work on my gyro, have the experienced factory people go over it, and add some upgrades. As I drove, I considered the upgrades I planned to install. Jim Vanek, owner of Sport Copter, has devised a simple rubber- clad extension on the prerotator belt engagement lever that applies a brake to the prerotator shaft pulley when the

KITPLANES May 2014 11 prerotator belt tension is released. This action kicks out the Bendix, making sure that the whole prerotator system does not stay engaged during flight. I have experienced the Bendix staying engaged during takeoff, which causes a lot of vibration. This simple idea solves that problem so it is a must-have. Also, greasing the shaft on which the Bendix travels requires removing it, applying grease, then reassembling. Safe- tying everything again is not a fun job, so Vanek solved this problem with a grease fitting in the top of the shaft with pas- sageways to keep the area under the Ben- dix well-greased. I love it when my work Sport Copter is working to integrate the Viking engine with the M912 airframe to pro- load is reduced, so this was another must- vide about 10% more power than the Rotax. have. The folks at Sport Copter never stop improving their products. the oil temperature up was to close off to impress my friends with this really Another reason for this trip to Ore- most of the radiator’s excess capacity cool idea of being able to change airflow gon was to install a smaller radiator. A with duct tape. At the Oregon factory, I through the radiator while in flight. gyro pilot/rancher in Australia, who installed a smaller radiator with adjust- One day as I worked on my gyro at goes by the handle of “Birdy,” told me able louvers so I can close them off as the factory, I noticed that Vanek was that my radiator was too big when I the weather gets cold. This replaces the intently looking at my horizontal stabi- posted pictures on the Rotary Wing need for duct tape, which actually works lizer. He told me to remove it because Forum. My cowboy solution to keep very well and is cheaper, but I am trying it did not look right. I removed it and Future Projects at Sport Copter The new projects at Sport Copter are material for a gyro pilot’s dream. shipping to customers. In the back room, where I was not While I worked on my gyro at the Sport Copter factory, they were allowed, they are in the design stage of a two place machine testing the Viking Honda Fit engine on a Vortex gyro. They constructed that will be similar to European tandem designs such as the a new mast and designed the motor mount to fit the Viking engine. Arrow Copter. This two-place gyro will have a full enclosure that With 110 hp, it appeared to be a viable engine for the Vortex since it allows the owner to fly in cold weather with a passenger, or produced more foot pounds of thrust in their test when compared to remove the canopy and fly out in the open with just a windscreen. the 100 hp Rotax 912 ULS. While this is an economical choice for more Many pilots want to take a passenger in a smaller machine, so power, the installation was not easy; there are always tradeoffs. Sport Copter is going to fill that desire, too. Stay tuned for The Sport Copter II, which is a two-place cabin gyroplane more developments. with lots of bells and whistles and a big Lycoming engine, is —K.S.

Sport Copter II cabins waiting for paint. Carbon-Fiber Sport Copter II cabin in paint booth.

12 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes using an electronic level on the spar, we discovered that I had bent the spar during one of my rough landings. After Vanek saw what I had done to the horizontal stabilizer spar, he changed to heavier tubing to make the spars stron- ger, which will withstand the heavy use a cowboy dishes out. My want list for this trip to the Sport Copter factory also included the idea of adding a trim system to my gyro so I can use both hands to take pictures (and other legal things) and the gyro will fly hands-off. When I brought up the subject, Vanek told me about the trim system used on the Sport Copter II. So, in the near future, we will have a power- trim system on my gyro operated with a toggle switch on the stick, much like the fancier aircraft. He is also testing the idea of a dampening system on the rotor to reduce vibration. After a balancing test showed that I had not caused any damage to my 27-foot rotor by flying roughshod, the rotor was mounted on the mast and tracked. The experts at the factory do this with reflectors out on the end of each blade, so they can use a flashlight to see each blade’s track. If the reflections are not on the same path, they make adjustments to the hub bar to bring them in line. After adjustments, my machine has considerably less vibration then before, and with the new dampener, it will be nearly vibration free and a great platform for taking pictures. J Karl Storjohann Storjohann Karl Karl Storjohann is a retired livestock nutritionist who used highly-modified conventional-gear Cessnas in his business to travel ranch to ranch for 40 years and some 6700 hours. He now regularly flies as a Sport Pilot in his aerobatic Sonex and Vortex gyroplane.

KITPLANES May 2014 13 Building the Bearhawk LSA

The start of a long, enjoyable tale. By Ken Scott

Another Oregon winter was just over “Got it!” I told my wife. “I’ll build an The Pudding River Bearhawk Gang: Phillip the horizon, promising the usual: sev- airplane.” Groelz, Ken Scott and Rion Bourgeois. Our eral months of low ceilings, gray skies She rolled her eyes. sombreros wouldn’t fit under our headsets. and rain. Having lived through 40 of “No, no,” I said. “This one will be them, I recognized the pitfalls. Without different.” two partners. I’ll get Rion and Phillip an interesting project to keep me busy, “How?” she asked. “Australian?” onboard. They’ll need a winter project, I’d find myself on the couch watching Ooof! On a trip to Australia as too. It’ll be great. It will go so much faster Cleveland play Buffalo…or worse. newlyweds, just after I’d finished my with three of us and it’ll be fun working Pondering the situation, I glanced RV-6, we had dinner with a bunch of with the other guys and I’ll learn all kinds through the screen of trees that sepa- RV builders. The wives took her aside. of new stuff and I won’t get bored…and rates my house from those on either side, “You’re sooo lucky,” they told her. “You besides…you already got me the plans for and from the grass airstrip that runs married him after he finished his air- a Bearhawk Patrol last Christmas!” through my backyard. On one side, my plane!” She’d never forgotten it—but Trump card. She’d surprised me neighbor Rion Bourgeois was putting on the other hand, she hadn’t objected completely with those plans, and now, the finishing touches on the Taj MaH- when I built another airplane. And probably to her surprise, they’d made angar he’d always dreamed about. On another after that. her an accomplice. the other, neighbor Phillip Groelz was “No. It won’t be a solo project like And that’s how Phillip, Rion, and taxiing around in the Christavia he’d the RV-12. Remember the KK-1, where I came to be sitting in my living room just completed. I had a partner? This time I’ll have sipping Oregon microbrew in front

14 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Building the Bearhawk LSA

Remember 27-inch CRT televisions? With the advent of the flat-screen, the boxes they came in are worth more than the TV. This one, with the addition of a screen and small squirrel cage blower, is our priming booth.

of the wood stove, Patrol plans spread the Patrol LSA. Despite already hav- across the floor. It wasn’t the first rodeo ing the Patrol plans, we found ourselves for any of us. Besides my all-aluminum attracted to the LSA. After all, we’re at an The first main wingspar going together. We used Stewart Systems water-based projects, Rion had built an RV-4, an age where an LSA makes a lot of sense… primer. It made our lives so much easier. airplane that takes a lot more work and Typical of Bob’s designs, the LSA was problem-solving than current RV kits. simple, clean, light and had that “just set by LSA standards. Bob’s reputation Phillip had completed two plansbuilt looks right” quality that some airplanes for straight talk and honest numbers gave projects: a Wittman Tailwind and a possess, although nobody can really us hope that we could at least come close Christavia MK 1 he’d taken over as a define it. At first glance the LSA is a to matching his performance and weight. moribund EAA chapter project. Our reworked Patrol, but actually it’s quite combined skill sets fit the Bearhawk a different airplane. It uses a different, The Team perfectly—Rion and I had plenty of no-flap wing and horizontal tail. The As a group we had several things going riveting experience, and the Bearhawk structure’s lighter, as befits an airplane for us, besides our prior experience. I uses a riveted aluminum wing. Phil- with lower power and Vne. The result is work for a company that would let us lip had been through two tube-and-rag a handsome tandem two-seat design with buy sheet aluminum and steel tube at airplanes, and the Bearhawk uses a steel- plenty of cabin space and decent perfor- favorable prices. Phillip had a collection tube fuselage. mance on a small Continental engine. of small Continental cases, cylinders, His prototype was the only one flying, and crankshafts that he was pretty sure The Plane but Bob was claiming 120 mph on a could produce one good engine. Rion Bob Barrows’ Bearhawk family includes C-75. With no electric system the empty had fallen in love with a lot of cool tools three airplanes. There’s the burly four- weight was in the order of 750 lbs—light while building his RV-4 and, of course, place Bearhawk that started it all, the enough to provide a decent useful load, still had them all. Even better, he could two-seat tandem Patrol and his newest, even with the 1320-pound gross weight supply an extra set of hands in the

A punch press turned out the main rib blanks, complete with Wingrib blank, ready to form. lightening holes, in a few seconds.

Photos: Ken Scott KITPLANES May 2014 15 person of his college-age son, Elliott, whom he hoped would use the airplane to learn to fly. Split four ways the LSA should provide loads of fun for a very moderate individual cost. So, we decided to take the plunge and join forces to build a no-frills Bearhawk LSA. Rion, a lawyer by trade, put together a written agreement with four shares and formed an LLC called Pudding River Bear- hawk. We all signed on. Once we’d all contributed an equal amount to the Bearhawk bank account, we were in business. Plans for Bearhawks must be ordered from Barrows himself, so the first check on our new account went to Fincastle, Virginia. A few days later, a roll of plans arrived. Twenty-nine Rion Bourgeois cleans small parts prior Phillip Groelz loads up the second main- 18-inch x 24-inch sheets and one full- to priming. spar with 5/32-inch rivets. size airfoil template were included. phrase: “scale drawing for dimensions work by one man at a drafting board, The Plan not shown.” There is virtually nothing and they achieve his goal. A customer expecting plans similar to about how to build the airplane—it’s At Bob’s recommendation, we decided those provided with modern kit air- expected that the customer knows or to start by making a set of wingribs. The craft like the Sonex, Carbon Cub, or will learn how to make the parts shown. Bearhawk has a constant-chord wing, so especially the RV series, would be in for It’s all understandable in context. all ribs are the same profile. I decided that something of a shock. No CAD system Barrows doesn’t have an engineering modern computer technology could help here—everything is hand-drawn. There department staffed with CAD drafts- us here and had the full-size airfoil tem- are no exploded views or part numbers men that can detail every nut and bolt. plate scanned at a local print shop. The and limited hardware call-outs. Spelling His job is to present enough informa- printed-paper version matched the mylar is, well, approximate. Fuzzy line qual- tion that people with shop skills similar drawing within a few thousandths of an ity obscures some of the details, and at to his can replicate his airplane. Those inch, so we saved the scan as a dxf file, the bottom of every sheet is the catchall drawings represent a heck of a lot of readable by machine tools. There’s a steel fabrication shop less than two miles from my house. They had no trouble plugging that dxf file into their laser machine, and after work, I picked up a perfect airfoil template, cut in 3/16-inch steel plate. This became our master template and the source of all subsequent dimensions for the ribs and spars of the wing. Getting Going In anticipation of the Patrol, I’d bought a router table and mounted a big Bosch router in it. This turned out to be the workhorse tool of the LSA project, at least in the early, parts-making stages. Using the steel template, we used router bits with bearings on the tips to produce accurate MDF form blocks for the main, nose and rear wingribs.

Details of the mainspar.

16 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes For the second mainspar, we gained access to a really big squeezer, built for WW-II aircraft production. We should all work so well when we’re 70 years old. The master airfoil template was laser-cut from 3/16-inch steel. We used it as a router and bought enough to do everything in punched or milled out of a single piece guide to make form blocks for the various both wings. It saved a lot of bending! of 1/8-inch aluminum.) wingribs. The winter months were spent pounding out, shearing out, cutting out The Future The usual method of producing flat parts. Spars front and rear, wings main, As things stand today, we’ve completed metal parts from Bearhawk plans is to nose and trailing edge, aileron spars and all the aluminum parts for both wing cut out the paper depiction, glue it to ribs, etc., etc., etc. A Bearhawk wing uses skeletons, except the parts for the fuel the metal with spray adhesive, then cut a lot of parts. (In hindsight, we could tanks. We’ve formed all the ribs, drilled it out by hand. We did that on some have simplified things considerably with all the spar components and, just last of the parts, where not too many were a little more computer work up front. weekend, riveted the first mainspar needed. For larger numbers of identi- For instance, the main wingspar could together. (Finally setting some rivets cal parts, like wingrib blanks, we used have been reduced from over 50 indi- after making all those parts was a real the same scanning technique that pro- vidual parts to five and the assembly milestone.) We’re having a great time… duced the airfoil template. We took the work probably halved if we’d had the and, just as I’d hoped, I have no idea who resulting dxf files to a local business that spar doubler strips and vertical supports won the Cleveland vs. Buffalo game.J makes aluminum parts for computer displays. In 15 minutes, their computer- driven mills and punch presses made enough spar fittings for three airplanes. Wingrib blanks were cut from sheet aluminum, complete with lightening holes, in about two minutes per rib—and accurate to something like two thousandths of an inch. The Bearhawk uses what seems like miles of thin aluminum angle to rein- force the ribs. Bob specifies 9/16-inch a side. Each main wingrib has four of these and each nose rib one—that’s over 200 angles. When I discovered that Van’s Aircraft sold 5/8-inch x 5/8-inch angle in four-foot lengths, we declared the extra sixteenth inch meaningless

The strut attach fittings were cut from plate stock and bolt to the mainspar.

KITPLANES May 2014 17 Choices in the stick grip market. By TOM WILSON

18 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes In a pushbutton world it’s easy to forget Sold by Aircraft Spruce in right, left and ultra (room for both a PTT and hat switch atop simplicity can still mother great things. the grip and a trigger in the front) variations, the $56.50 Teakwood pistol grips give an This plain wooden ball is the grip atop Mira organic, classic look to a cockpit. The polished wood texture has a natural feel and with Slovak’s Bücker Jungmann, and what it their slightly compact sizing are great for tight cockpits or smaller hands. The right and lacks in sophistication is more than made left versions accommodate a single PTT switch atop the grip. up for by the talent holding it. It may not be the first thing builders grip. This is can be a deceptively simple microphone from the instrument panel talk about, but sooner or later, you’re task at first blush. But the more you anymore—and presto, you now have going to need to select a stick grip. And consider what functions a stick grip can wires up the control stick and a momen- like everything else today, there are control, and that it’s both highly visible tary switch on the grip. more choices and considerations when it and a touch point in the cockpit, the The fun begins as the panel fills up comes to dressing the top of your home- more decisions you’re faced with. with electric gadgets. Probably the first built’s control stick. From a polished axe For simple airplanes—LSA and aero- to arrive is electric pitch trim, which handle to a jet fighter’s Christmas tree of batic birds come to mind—the need can needs either a rocker or toggle switch. switches and coolie hats, there’s no lack be only to cover the top of the stick’s of choices in today’s market. metal tubing to avoid cuts and give a secure handhold. But thanks to head- Uses For All Define the Need sets, just about everyone adds a push- First, of course, you must decide on to-talk (PTT) switch for radio and Those Buttons what it is you’re looking for in a stick intercom duties—no one is picking up a • Aileron trim • Autopilot engage/disengage • Co-pilot stick switch disconnect

▲ Typical of Van’s products, their injection molded black nylon grip is no-nonsense, (Young Eagles) affordable at just $45, and offers only what • Dynamic balancer on/off (helos) you need: a comfortable grip, single drilled • Elevator trim hole for a coolie hat switch, plus room for • EFIS display toggling you to drill another hole for a PTT switch. It’s available strictly for 1-inch sticks and • Flaps right-hand use. And because it won’t clash • Frequency flip-flop aesthetically with a plush pilot’s cockpit, it • Intercom/radio select makes a good copilot’s grip in tandem seat • Push-to-talk (radio 1 & 2) aircraft, too. • Pilot/crew isolate • Rudder trim ▲ It doesn’t get any simpler than Aircraft Spruce’s rubber grip from BSP Aero. An • Smoke on/off easy $12.95, it’s thicker and cushier than • Speed brakes it looks and damps buzz job machinery • Spoilers better than the hard vinyl alternatives. • Transponder ident Designed for 1-inch sticks and T-88 adhesive application, its instruction sheet • Video camera on/off says a few wraps of electrical tape will • Water ballast dump (glider) make it work on smaller-diameter sticks. —T.W.

Photos: Tom Wilson KITPLANES May 2014 19 Add in two-axis trim and you need either a second switch, or much better, a cone-shaped, four-way, coolie hat switch. By the way, such hat switches can easily be wired to work in just two directions if you want the good ergonomics of a hat switch but need only two functions. Also common are electric flaps, which, while still often switched from the instrument panel, are finding their way to the grip. Chalk up another toggle or rocker switch to cover the “up” and “down” functions. Autopilots are now the norm on cross-country airplanes, and here the typical need is to simply disengage the AP. Any old button on the grip eases that action, but it’s smart to place the Flight Grips are modular, designed to be finished from a wide choice of switches as AP disconnect a hair off the beaten the customer wishes. Typical examples are the Model 2 (left) at $127.75 featuring a path because inadvertently giving Iron 2-way rocker trigger switch and a plain faceplate at top. The Model 4 (right) is $149.95 Mike a smoke break can have interest- ($172.75 left-handed) and adds the two top-mounted buttons. Many other variations are possible. ing consequences that might take a few seconds to show up. Once the PTT, trim, flaps and autopilot are on the grip, personal preference and specialized needs seem to drive other operations we’ve found on grips. Some of these seem rather useful, such as controlling the frequency flip-flop on the com radio, flipping through EFIS displays, or even mounting a second PTT for the second com unit or intercom. But we’ve also seen the transponder ident button on the grip, which comes dangerously close to the same La-Z-Boy mentality which gave us an “auto” setting on our car’s headlight switch. Of course, being able to toggle accessories on and off from the grip can be a real boon to piloting performance. Aerobatics go better with smoke, and where else to put the smoke switch than on the grip (or the throttle)? And if you’re having that much fun, toggling the on-board video camera into action is another stick grip natural. One application we came across in our Ray Allen makes a wide-ranging, popular The two-way rocker switch in the trigger research was a switch on the pilot’s stick line of grips and autopilot controls, easing position is a constant of the Flight Grip grip to de-activate all but the co-pilot’s integration of the two systems. This is line. It’s a clean way of getting two func- PTT switch. Just the thing for Young Allen’s basic G101 foam grip (high-grip, tions—PTT radio and PTT intercom—in a vibration-damping). It has a nice barrel small area. Toggling the rocker upwards Eagle flights or anyone else you don’t shape, a single PTT switch under the as shown isn’t quite as natural as toggling need re-trimming your airplane or who thumb, and sells for $36.95. down, so we’d put an occasional use in is afraid of “doing something wrong.” that position.

20 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Preprinted, adhesive labels are provided with Ray Allen controls. They’re a bit basic, but provide great adaptability depending on how you configure your grip’s switches. There is a PTT button on the forward Still using the G101’s foam grip, Ray Allen offers a line of inserts with multi-function heads radius of the G205/G207 controls in addi- to arrive at the $109.85 G205 and $148.95 G207 grips. These are the G205 and G207 heads tion to the switches seen here. by themselves, unlabeled, just the way they come out of the box. Ray Allen instructions are excellent and installation and wiring appear easy. Alternative Sources Scrounging seems less revered in home- building in these modern times, but it’s still a good way to get in the air on the cheap. While we’re convinced you’ll be happier with a dedicated aviation grip, people have been making do with everything from vinyl grips off tricycles (we’d cut the streamers off) and garden equipment to that old favorite—video game consoles—for decades. In fact, more than a few people in the homebuilt grip business started by making video game grips, and yes, a few of the grips featured in this article are from molds first built for gaming. There are always surplus markets, although the warehouses full of WW-II era parts and equipment that made home- building so affordable in the 1960s and 70s were emptied long ago. If you’ve got lottery money to get rid of, you could (maybe) buy current military/com- mercial/space hardware. Mason (look them up under Esterline Technologies Corp.) makes the F-16 stick, grip, and throttle handle, for example. It’s all very butch, hewn from heavy, indestructible investment cast aluminum, but comes rigged only with potentiometers for a fly-by-wire control. Getting Mason’s grip from an F/A-18 is another bragging rights option, Ray Allen also offers a series of hard plastic grips. All have a PTT switch in front and range from the plain-top, $64.50 G301 at left to the full-featured $157.75 G307 at right. but the readily available Infiniti and Otto are There’s no molded-in thumb rest here, but the rounded top does make a good thumb essentially the same for merely a lot of money. perch, and allows resting the palm of the hand on top for a change. —T.W.

KITPLANES May 2014 21 Design Considerations We thought we’d find many variations in stick grip sizes, the better to accommodate different size hands, but we didn’t. Yes, a few grips are smaller than others, and a few similar looking grips have subtle shape differences that you can feel in back-to-back testing, but none of these were meaningful in our opinion. If hand-fit is a concern, all we can say is you’ll have to try a few on for size. More meaningful are variations in feel between simple plastic moldings, wood, and rubber-coated plastic textures. This can be a big deal to some folks and a non-issue for others; you might want to consider test driving a few grips at the The basic Tosten grip design is inherently ambidextrous and fits a typical PTT and momen- big airshows if you’re picky on surface tary switch on the forward face (typically the lower switch is an autopilot disconnect). Coolie feel. Tosten offers an especially attrac- hat and switch options on the rear face allow four variations: CS-2, -4, -6, -8, with the $129.00 tive rubberized finish. CS-6 (lower left) and $139.00 CS-8 (lower right) the most popular among customers who have autopilots. The $119.00 CS-4 (no coolie hat) is the best choice for those without an autopilot.

Tostens, like Fatboys and Infinitis, come pre-wired for a worthwhile time savings. Further- more, all Tosten grips are 66% nylon and 6% fiberglass for hammer-tough durability and acetone-friendly cleanability, plus Soft Touch coating is a $20 option. This is the same rubberized coating found on cell phones and high-end cameras. It gives a smoother grain and a warmer, more premium feel you’ll really like.

In many ways Tosten grips are at the happy confluence of design, features, and affordability. All Tostens feature a unique mounting where the grip has a molded-in steel post slipped into a Tosten bushing placed in the end of the control stick. A set screw allows clocking the grip in any head- ing, an adjustment easily reset at any time. Collateral considerations are the Tosten post mount requires six inches be cut off the stick, and there is a built-in angle to the grip. Rarely, this can be an issue in tight cockpits where the grip intersects the bottom of the instrument panel, but typically, LSA or other basic aircraft are the market for Tosten’s approximately $55 CS-3 grip. It’s simple as in the RV-12, the finished length and but nicely made, can be had with Soft Touch coating for $20 extra, and features a PTT trigger angle work out nicely. and a 2-way trim switch atop the grip. It also uses the adjustable Tosten post mounting.

22 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes While visiting Tosten we got a glimpse at the future, a military style grip still being worked up as an injection molding fixture. It will use the Tosten post mount and a full suite of switch work. Uniquely, however, the side plates are separate, allowing unprecedented flexibility in switch mounting—even a side-mounted coolie hat for our editor-in-chief. This also makes the grip ambidextrous. Expect it to debut at AirVenture 2014 for around $180.

Switch placement can loom large as a personal preference. Your aerobatically- inclined editor wants his coolie hat trim switch mounted at an ergonomic angle for natural action during vertical maneuvers; so far, all hat switches have been mounted perpendicularly atop the grip. Now it seems Tosten is developing just such a grip, so we suppose it doesn’t hurt to voice an opinion! One thing to watch for is clearance between the instrument panel and the grip (or more accurately, your hand). Smaller cockpits can have little room between the panel and a stick pushed well-into the nose-down position. It might be that a simpler, shorter grip gives more clearance. Another popular discussion is whether to mount the grip straight ahead or angled. We’ll get to that in just a minute, but from a design standpoint, understand that almost all grips are either glued or through-bolted to the stick. This makes reorienting them after installation practically impossible. The one exception is Tosten grips, which use a set screw arrangement for slick and quick grip reorientation.

KITPLANES May 2014 23 Installation Thoughts There’s nothing terribly taxing about fitting stick grips into your project, but it is one of those little corners of the airplane that benefits from thorough planning because the grip’s electrical tentacles can range from engine to wingtip to rear nav light. In short, it’s necessary to decide on the functions you want in the grip before shopping for grips. Be aware that some grips, trims and autopilots require relays to operate. That’s not a direct issue when select- ing a grip, but it is something to budget airframe space and, of course, money, One area with few choices is matching throt- In any group there is always one offering for. If you have an electronically com- tle and stick grips. Luckily Fatboy Flight- towering over the rest. In stick grips plex airplane coming together, fitting works does offer just such a pair in their it’s the Otto B8 at $730.00 once fully- something like a Vertical Power circuit quadrant ($360 plus grips and switches) dressed. Functionally it covers the same ground and is the same overall size as the breaker box might help rationalize the and stick grip. Both are customizable with a variety of nice switches, so chores can be Infiniti military grip, but the difference wiring to/from the stick. spread between stick and throttle. Sounds is in finish and switch quality. In short, it To fit the grip in the straight ahead like a natural for aerobatic ships. Pricing is feels like a million bucks—real Jet Com- position or angled to the side is an argu- based on the number and type of switches; mand stuff—and because it’s a one-piece ment for the ages. The straight posi- the stock grip shown here is a $260 Romeo molding, there is no big seam running down the middle. tion might look better to show judges 3H. The throttle is a $225 2H. if you’re into that sort of thing, and it offers more flexibility on long cross countries where you might want to switch hands occasionally. On the other hand—very puny, we know—an angled grip can be less fatiguing to the hand/wrist it is angled for. And worries about an angled grip skewing the mental gym- nastics of pulling or pushing the stick are moot. We’ve yet to find the pilot who said he wished he had put his grip on straight because the angled mounting was disorienting.

Thanks Spruce! Probably the major variation in the Infiniti grip selection is if you have electric flaps or not. A metal toggle switch (push up is on/off, push down is momentary) is provided for flap- Helping us with the big task of gather- equipped aircraft. Non-electric-flap models get color-coded, round on/off switches. There ing the majority of the stick grips for this are no exposed screw heads except for the single mounting bolt at the bottom. article was Aircraft Spruce & Specialty Co. “Spruce” carries nearly all the grips Military grip fans naturally gravitate covered in this article, so their generosity to the Infiniti line hovering at $199.95, in pulling many grips from stock made our although you might spend another $40 on optional switches or stick adapters. photographic job immensely easier. Options abound, such as this left- and We’ve also used Aircraft Spruce’s pric- right-hand pair; all are prewired with ing wherever possible, as it’s obviously generous wire sizing, insulation and real-world; and their huge reach around markings. Infiniti build quality is high, the the globe means almost anyone can instruction sheet a bit basic, but easily supportive of the guy who knows his way comparison shop that way. around the shop. Relays are required for —T.W. the coolie hat wiring.

24 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Obviously this straight vs. angled argument is a personal preference question, but we’ll observe more complex, anatomically-formed grips are likely best mounted at an angle, while simpler grips don’t matter so much. Interestingly, many smaller, more agile planes are mainly flown via the fin- gertips rather than the grasp Steve Canyon used to manhandle his F-102, and then the ergonomically-shaped grips can be confining on long flights. It might be a simple ball or rubber tricycle-handle grip that allows the desired flexibility in such cases. Something else to consider, especially on installations with all the bells and whistles, is feeding all those wires up the stick. Sticks are commonly Big attraction—literally—with the Otto B8 is the 5/8-, ¾- or 1-inch tubing, with a few warbird/military applications sporting a large, super-quality switches. Otto is primarily swaggering 11/8-inch stick. If you have a lot of wiring, we recommend a 1-inch an aerospace switch manufacturer and it shows. stick for wire routing. Go smaller and you may have to re-wire a pre-wired The PTT is way oversized and has a smooth, Infiniti or Tosten stick (it’s been done). Go larger and you’ll be limited in the buttery action that makes everything else feel cheap. Just the thing for warbird restos, jets, direct-fit grip installations and could likely need to fabricate an adapter to and the money-doesn’t-matter crowd. The Otto get your intended grip joined to the stick. comes completely unassembled, has a rudimen- Ultimately grip selection is a personal choice as much as filling a mission tary instruction sheet at best, and is obviously requirement. The happy news is there are plenty of options to choose from. designed for pro installation. My Favorite Grip Building the perfect cockpit has always been one of my goals. And while I know that is fundamentally impossible, it is always nice to have a target. At the heart of the cockpit, I have to place the stick grip—the part of the airplane that most directly connects the pilot to their bird. I have flown a lot of different airplanes with many different styles of grips; some were great, many good, and some, of course, absolutely terrible. I like a grip that feels solid in my hand—not something that feels like it came off a cheap video game. Depending on the complexity of the aircraft, and the uses for which it was designed, I like to have appropriate switches on the grip. I don’t like complication for complexity’s sake; but it is nice to be able to handle routine cockpit chores without releasing the stick. In a J-3 Cub, all you need is a simple non-skid coating on top of the steel tube. In a high-complexity IFR machine, control of many things at the touch of a finger saves time and effort. More important (to me) than the number of (or lack of) switches on the grip is the ergonomics of how it fits the hand for the functions placement, it was all for naught; the fly-by-wire system was built to that you want to perform. I find that almost all of the commonly automatically keep the vehicle in trim. It is a rate command system so available grips have one serious flaw when it comes to the trim coolie that if the pilot is making no input, the vehicle holds attitude, regard- hat—the switch is generally placed on the top, in the center. This less of the trim settings—so the trim switch was mostly superfluous. is most definitely not where the human thumb lies when naturally Aside from the trim switch, the Shuttle RHC had only two other gripping the stick; the thumb wants to tuck in on the side. I have only buttons—despite the fact that this was probably the most complex flown one grip that puts it in this natural spot—the grip designed for flying machine ever built. The trigger switch was used for push- the Space Shuttle Rotational Hand Controller. to-talk, and the big red button on the top was used to engage the The Shuttle RHC is the primary flight control for maneuvering, and backup flight system software should the primary avionics software the coolie hat is on a little shelf on the left side. This is right where fail. While I like the layout of the grip better than any other, the truth the thumb of the right hand wants to rest while flying. You don’t is, I wouldn’t want it in my homebuilt aircraft exactly as it came out need to change your grip in the least to get to the trim—unlike the of the shuttle because it is a little too large. The RHC was designed thumb wrestling necessary to operate a hat switch top and center if to be used with pressure suit gloves, and as such, most would find it you have a load on the stick. Ironically, the Shuttle RHC was designed about 20% too big for comfort. But downsize it a little and you’d have very early on in the program, before the flight control system was a winner—and a conversation piece to boot! J fully developed. I say ironically because with the perfect trim switch —Paul Dye

KITPLANES May 2014 25 Protecting your cowling from excess heat. By ERIC STEWART

Regardless of whether your aircraft is pipes (or a turbo) can be a problem. It’s cowlings, some kind of a heat shield may metal, composite, or tube and fabric, quite not uncommon for builders to find blis- be required. a few homebuilts these days use compos- tered—or even burnt—cowlings during ite fairings. Nowhere is this more true Phase I testing, or after an engine swap What’s My Clearance? than the engine cowl—it’s just not an easy or other firewall-forward modifications. To find out what kind of clearance shape to fabricate out of other materials. If you are making your own cowl, use of between cowl and exhaust pipes is Unfortunately, for tightly-cowled instal- a high-temp epoxy is an option, but for typically necessary, we went straight to lations, heat from proximity to exhaust those of us working with kit-supplied the exhaust master himself—Larry Vet-

26 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Clay cone stuck to the exhaust pipe to check for clearance. The impression left by the fiberglass cowl can be seen on the clay. The stick pin plumbs the exact clearance. terman. Although Vetterman is now up top are well sealed to improve that function as a heat sink is compromised. retired, his 27 years of experience man- mass airflow cooling. Vetterman has seen no evidence that ufacturing exhaust systems for Experi- And, if you’ve considered using wrapping improves power or speed. mental aircraft have made Vetterman automotive-style exhaust pipe wraps to Finally, although this article is exhausts the gold standard among manage under-cowl heat, think again focused on keeping your cowl from get- homebuilders. Vetterman flies behind says Vetterman. “Wrapped exhausts ting toasted, Vetterman points out that his own pipes in an RV-7A. are a serious issue. I’ve seen numerous it’s extremely important to also protect To begin with, it’s important to examples of pipe failure caused by wrap- fuel lines and control cables in the vicin- understand the heating and cooling ping. When I asked a metallurgist sev- ity of hot exhaust pipes with heat shields of the pipes themselves. “What build- eral years ago what was happening, he mounted directly to the pipe. ers need to realize is that the pipes explained that if the surface of the pipe are hottest in two areas,” says Vetter- exceeds 1250° F, you see serious degra- Determining Actual Clearance man. “First, because of valve overlap, dation of the metal as the chromium So, what kind of clearances does Vet- the flame front in the pipes is about and other additive elements used to give terman recommend? “For unprotected two inches from where the pipe flange Type 321 stainless its high temperature fiberglass, I would recommend not less bolts to the cylinder head. In cruise properties oxidize.” In addition, wrap- than 1½ inches of clearance. For fiber- flight, this area of the pipe will actu- ping the pipes is likely to put additional glass with either foil or silver paint, you ally be cherry red. You can see this in heat stress on the engine since their can reduce that to ¾ inch.” The addition the discoloration of the pipes—when you look at the flange, you’ll see that it stays a normal color at the cylinder but turns brown about two inches down- stream. Incidentally, this is where your EGT sensors should ideally be located. The second location of high heat is the branch on crossover systems, since this is getting a double whammy of exhaust. “On the other hand, we need to appreciate that the exhaust system is one of the best heat sinks on an air- cooled engine. The mass airflow coming past the cylinders continues to pick up heat as it passes the exhaust pipes.” So, in addition to the thermodynam- ics of the exhaust gases cooling as they expand towards the pipe exit, cooling airflow causes the exit end of the pipes to be significantly cooler than the Here’s what you’ll need (clockwise): Laminating epoxy, adhesive-backed foil, Fiberfrax flange end. Therefore, one of the first and a straightedge, a half pint of Pliobond adhesive, modeling clay, a sharp X-Acto knife steps in dealing with excess heat down for trimming the foil, a Sharpie for template layout, an acid brush to seal the edges of by the pipes is to make sure your baffles the foil with epoxy, a window-tint applicator, and paint.

Photos: Eric Stewart KITPLANES May 2014 27 of an insulator like Fiberfrax will provide additional protection. These numbers of course represent a rule of thumb and Vetterman stresses the importance of airflow in keeping things cool. In that sense then, an area of static airflow is of greatest cause for concern. In determining your own cowl’s hot spots, it also helps to find someone else with a similar installation and compare notes. If you want to be truly scientific, you could use something like Omega temperature labels (www.omega. com) and make a temperature map. In order to determine the exact cowl clearance from the exhaust pipe at any Here we can see the Fiberfrax, which has already been glued to the inner cowl with particular point, roll a bit of modeling Pliobond, being covered with the adhesive foil. clay into a cone slightly greater in height than the estimated clearance. Stick the highlight oil leaks. Some builders fill out, if you need to repair the fiberglass in cone to the pipe in the region of inter- and smooth the interior of their cowls the future, it will be impossible to do so if est, and carefully assemble the cowl. just as they would an exterior surface, it has been contaminated with oil. Some Give the cowl a light tap in the region since a smooth surface facilitates easy builders thin the epoxy with acetone, but of the cone, then remove. The cowl will clean up and is aesthetically pleasing. I don’t find this necessary—simply paint have made an impression on the clay However, this is not necessary, and it on a single thick coat with a brush and which you can then “plumb” with a does add weight and build time. wipe the excess off with a rubber squee- stick pin to determine the precise clear- Before painting, it is recommended gee. Let cure and follow with your choice ance. You may want to subtract another that you at least seal the entire inner cowl of paint. Even if you plan to put down 1/8 to 3/8 inch from this measurement to with a nice fuel-proof coat of laminating additional heat barrier layers, you’ll still allow for vibration of the cowl, engine epoxy. (Laminating epoxy is much less want to seal everything with epoxy as a or pipes themselves. viscous than structural epoxy and there- kind of base coat. fore easier to apply; I recommend West Level 1 Protection/Rare: Systems 105 Resin and 206 Hardener.) Level 2 Protection/Medium-Rare: White Paint This helps keep oil and gas from soaking Adhesive-Backed Foil At a minimum, simply painting the into pinholes or core material, which can The next level of protection is adhesive- interior of the cowl white or silver will add weight and compromise the strength backed aluminum foil. Both Aircraft help to reflect radiant heat, as well as of the cowl. And as Vetterman points Spruce & Specialty Co. and Van’s Air- craft, Inc. sell foils. (Van’s is happy to sell many of their products to all homebuilders, not just those who have purchased their kits.) The Van’s product is 30 inches wide and adheres very well; I highly recommend it. You’ll want to make templates for the area of application (better to waste template material than foil) and to get an idea of how many linear feet of foil you’ll need to order. I find the 1/16-inch thick closed-cell foam often used for packing material these days perfect for templates, since it is slightly rigid, but still conforms nicely to compound curves—like the foil itself. The foil cuts easily with either scissors Here we can see the 1.5” perimeter anchor of adhesive-backed foil over a layer of 1/16- or an X-Acto knife and straightedge. inch Fiberfrax. The foil is squeegeed to the edge of the cowl hinge pin, trimmed with an It is extremely sticky, so make sure you X-Acto knife, then the edge sealed with laminating epoxy to prevent lifting. have it positioned exactly where you

28 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes This is pretty substantial stuff. It is quite heavy at 9.5 ounces per square foot, ver- sus less than 1 ounce per square foot for either 1/16-inch Fiberfrax or Van’s adhesive-backed aluminum. Due to the sandwich construction, it doesn’t conform to compound curves as well as the thinner materials, and it relies on rivets or glue to be held in place. In addition, due to the open edge construction, you’ll definitely need to anchor the perimeter with aluminum tape to keep the blanket from getting oil-saturated. Where to Start? Finished product: Entire inner cowl was sealed and painted, followed by application of While some builders apply foil to the Fiberfrax and aluminum foil in areas of close proximity to exhaust pipes. entire inside of their cowl, this probably isn’t necessary. Unless you have want it before laying it in the cowl. This aluminum foil whose edges extend one extremely close tolerances from the get- is another reason to put down a layer or two inches beyond the Fiberfrax. go (i.e., less than 1/2 inch), I’d probably of epoxy—the adhesive backing sticks This extension will serve to anchor take the first step of epoxy seal/white best to glossy surfaces. I prefer to work the foil around the perimeter of the paint, then go fly. During Phase I, you’ll from the middle outward, as this seems Fiberfrax. Peel the backing and lay this be pulling the cowl off quite a bit any- to minimize the number of creases on directly over the foil, again working way to make sure everything is secure, compound-curved surfaces. Use the from the center outward. Finish up by and if you are toasting the cowl, the felt edge of a window-tint application sealing the edges with laminating epoxy. paint will tell you pretty quickly. How- tool, available from a car parts store, ever, once you’ve got your base layer of to smooth the foil as you go. Once fin- Level 4 Protection/Charbroiled: epoxy and paint, applying the Fiberfrax ished, mix up some laminating epoxy Firewall 2000 and aluminum won’t take more than a and paint the edges of the foil with an The nuclear option of heat barriers is a few hours and will add less than a pound acid brush. This will prevent oil seeping product like Firewall 2000, a quarter of weight, so don’t be afraid to take a under the foil as well as the foil lifting. inch of insulator sandwiched between preventative approach. Given how much aluminum foil on one side and stain- many builders hate fiberglass work (and Level 3 Protection/Well-Done: less steel on the other. Unless you have how expensive cowls are), this is one case Ceramic Blanket a glowing turbo an inch from your cowl, where an ounce of foil is worth a pound If your clearances are minimal, you’ll avoid the “bigger is better” temptation. of Bondo. Good luck, and stay cool! J want to consider adding an insulator. Aircraft Spruce sells a variety of insu- lating blankets. We encourage you to do your own research, but try not to get carried away with high-tech multi- layered blankets that promise to deflect space shuttle-magnitude heat rays. For most builders 1/16-inch Fiberfrax is more than adequate (1/8-inch is also available). Fiberfrax is a ceramic blanket that can be laid under the aluminum foil to greatly slow heat transfer. As with the foil, first make templates of the region you want to protect. Cut out the Fiberfrax, and attach it to the cowl with Pliobond contact cement. Use regular Pliobond—VOC compli- ant isn’t nearly as effective. Now, using Close-up of Fiberfrax/foil barrier adjacent to an exhaust pipe. (Pipe hidden behind your original template, cut a sheet of intake runner.) Epoxy to seal the edge has not yet been applied in this picture.

KITPLANES May 2014 29

Have you ever been deeply immersed in a shop task and mumbled to yourself, “There must be a better way”? You’re not alone. The truth is that aircraft fabrication professionals have the same thought almost every day. In this series we’ll take KITPLANES® readers into a variety of professional settings, looking for ideas, methods, products, and concepts transferable to the home shop. You’re going to meet some very clever people. Some of their solutions are complex, but others are so forehead-slapping simple that you’ll wonder why you didn’t already think of it. Enjoy!

Jim Kimball Enterprises

Building the better biplane. By DAN HORTON

This month we’re visiting Jim Kim- to airbrush an elaborate “snake scale” ball Enterprises, in sunny Zellwood, scheme on a client’s custom Pitts, and he Florida. The Kimball family and staff came onboard full time a few months have been cranking out award-winning later. Clint still does some personal air- restorations, one-off customs, and multi- brush projects for fun, including radio ple variations of the famous Pitts Model control aircraft, motorcycles, and the 12 for more than 30 years. There is much most recent livery on the Reno racer for the homebuilder to learn from a Precious Metal. He also enjoys tradi- shop like this. tional art projects like sculpture. Let’s start in the paint and cover shop. Kimball Enterprises needs a painter Our pro is Clint Sweet, the man respon- with Clint’s wide range of skills. With Clint Sweet sible for shooting the fabulous paint the exception of kit component pro- seen on recent Kimball creations. duction, all projects are custom, one- can do it better. Most Kimball clients Clint is not your average painter, off creations. Some clients arrive with are referred to Mirco Picorari of Air- having received formal art training at a very specific idea of what they want craft Design Studio, in Modena, Italy. If the college level (he earned a B.A. in their airplane to look like, perhaps a you attend the Oshkosh and Lakeland illustration), then gaining a reputa- favorite theme, or a particular WW-II fly-ins, chances are you’ve seen Mirco’s tion for his airbrush work in the cus- layout. Others desire design services, work on airshow aircraft, the jets in tom motorcycle industry. Years ago which brings us to our first pro tip: real FBO parking, and even color picks in Kevin Kimball contracted with him professionals know when someone else the Vintage area.

Photos: Dan Horton KITPLANES May 2014 31 A typical Picorari design for a Model cross coats of Poly-Brush followed by 12 might include multiple base colors, four cross coats of silver Poly-Spray. color fading, stripes, checkerboard, The component is allowed to cure a few and lettering or logos with airbrushed days, protective masking tape is placed details. The paints selected could be over all protrusions and rib stitches, solids, metallics, or pearls, often in the and then it’s time to sand. same scheme. The actual execution falls Traditionally, fabric work is hand- to Clint, no matter how complex. He sanded, but in the Kimball shop the starts by shooting a small sample panel majority is done using a pneumatic for each color and feature. Those panels palm sander with a foam rubber foot. go to the client for approval, but the pro- All sanding is done wet, using 220 grit. cess of creating them allows everyone to The jitterbug works fine across the open understand application and color details panels and along the pinked tape edges, The secret weapon— a $26 jitterbug that might otherwise not be realized after which the masking tape is peeled sander from the import tool store. until later. That’s a very good lesson. Far and fine details are worked by hand. The too many homebuilders get their first process removes all the fabric nits, fuzzy line, usually DBC base and DCU2021 experience with a spray gun by shooting pinked tape edges, and any airborne clear with a flex additive. new airplane parts. They expect great dirt that may have crept into the paint In a typical automotive application, results, and they are often disappointed. process. The panel is washed to remove Deltron DBC color base is catalyzed Contrast that approach with Clint’s sanding debris, and when fully dry, it by the hardener in the DCU clear, method. Here’s a guy with huge experi- gets two more cross coats of silver. A which must be sprayed over the DBC ence, yet he takes the time to understand light scuff with 400 grit on a soft block within a tight time window. However, exactly how the paint will go on before follows cure, then it’s time for color. the DBC itself may be catalyzed, and he ever points a gun at a flight article. Topcoats vary depending on aircraft Clint says he routinely does so. Kevin type. The restoration of a certified pro- and Clint feel they get a tougher finish, Secrets of Fabric Finishing duction aircraft requires a restorer to but it also relaxes the clearcoat time con- Most Kimball fabric work is done using follow the covering system STC in straint, and eliminates concern about the Poly-Fiber process. Kevin considers detail. In the case of Poly-Fiber, the total thickness. Both considerations it a reliable base, an important point STC requires using Poly-Tone or Aero- are important, as the typical scheme when you think about the time, effort, thane color coats. There is no such includes multiple colors and takes time and money invested in a typical cli- requirement for an aircraft licensed to tape, mask, and spray. ent’s custom paint. The actual fabric in an Experimental category, and for With all the colors in place, the next application, with a few exceptions, is those the Kimball preference is for PPG step is usually three coats of clear. If the conventional. After filling the fabric products. A typical application uses a scheme includes airbrushed detail, the weave, a typical finish starts with four basecoat and clearcoat from the Deltron cured clear will be wet-sanded, then

DeVilbiss GFG670 Plus for big panels. DeVilbiss SRi Pro for trim colors and details.

32 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Solar Flux allows welding stainless tube Fuselage weld sequence. without a back-gas purge. airbrushed, then covered with two one large exit fan. The booth is care- more than a decade, welding Model more clear coats. Although the finished fully cleaned before spray sessions, and 12 kit components, exhaust systems, clear on metal components can be cut all surfaces are wetted. Aluminum rails fuel tanks, and anything else you can and buffed, Clint avoids running a are suspended from the ceiling beams, imagine. TIG welding is used almost typical 1900 RPM buffer on fabric, as under which small parts or whole wings exclusively, as it produces excellent joint the frictional heating under the spin- can be hung at a convenient height. quality in a wide variety of materials. ning pad can do funny things to heat- Wings are hung with the chord line Stainless steel exhaust systems for the shrunk polyester. vertical, and with the least-seen side fac- M14 radials are 312 alloy, joined with The spray guns in the Kimball shop ing the booth air inlet, both tricks to 308 filler rod. When welding stainless, are not wildly expensive. The two hang- minimize the chance of noticeable dirt it is necessary to shield the back side of ing in the booth on the day of my visit or nibs in the paint. A compressed air a weld from the atmosphere. Failure to were a DeVilbiss GFG670 Plus, and a filtration system provides spray gun air do so results in what welders refer to as DeVilbiss SRi Pro for detail work. Clint and breathing air for a mask. “sugar,” an extremely grainy, rough, and uses a cup liner system, as it allows him I asked Clint what he considered the weak weld surface. There are two ways to spray at any angle, including upside best advice for great paint. He said sim- to provide shielding, back gas purge or a down. Cheap guns are used for primer ply, “Take your time.” protective flux. A back gas purge means work, per conventional practice. piping argon into the tube assembly in There’s nothing fancy about the Kim- The Welding shop order to exclude the atmosphere. The ball spray booth. It’s a walled off corner Jeff Woodham is an artist with a TIG alternate method simply requires spread- of the big hangar, with inlet filters and torch. Jeff has been with the Kimballs ing a layer of flux on the inside of each

Left: A filler rod for every purpose: aluminum, stainless, 4130, titanium, and more. Right: Jeff Woodham.

KITPLANES May 2014 33 An aileron perfectly aligned in the jig. Temporary anchors secure the aileron to the jig. joint before welding. Jeff likes Solar Flux. Special lightweight Model 12s get forward one station and starting the He mixes it with any fast evaporating titanium components, and Jeff welds process again. It’s almost a faith-based solvent to make a paste, then paints the those too. With so many different kinds task. Partway through the process the paste inside the end of each tube before of filler rods in the shop, it becomes fuselage will look warped, but don’t positioning for the weld. The result is a important to keep them organized. worry; when you finish the last cluster at clean, sugar-free joint, without the setup In the Kimball shop the rod rack is the firewall it will be straight again. time or cost of argon gas. mounted right on top of the welding Aluminum skins and tanks are mostly machine. You might want to build one The Aileron Jig 3003 alloy, for which Jeff uses a soft 1100 as a practice project. Roll rate is a big deal in the aerobatic filler rod. Although 1100 is low-strength, The shop workhorse is a Miller Syn- world. Eye-popping rotation requires an it is very ductile. The soft rod allows skin crowave 250 machine with a water- aileron with a length nearly the full span seams (in welded wheelpants, for exam- cooled torch. Jeff and Kevin like of a wing panel. So how do you build a ple) to be hammered and re-formed as Miller machines. very light, very long, perfectly straight desired. Structural aluminum parts are Want to weld a fuselage frame with- all-metal aileron? usually 6061 and get a 4043 rod. out warpage? Try the rotational method. Initial assembly is dirt simple. The nose In the Kimball shop (and many oth- After tacking, start at the tailpost, weld ribs and main ribs are riveted to the spar, ers), the standard filler rod for 4130 all the clusters, then move forward one then the trailing edge is attached. Next, steel tube is ER80S-D2. The exception station. Weld a complete cluster, then the hinge hardware and counterweight is a 4130 component that will be oven move to the next cluster at that station assemblies are fastened into place. heat-treated to some engineering-spec- in a clockwise or counterclockwise pat- At this point the aileron is still quite ified high strength level after assembly. tern (it doesn’t matter which; just pick flexible in torsion. It is the leading edge It is very rare to find such parts in sport a direction and stick with it). Work D-cell which stiffens the aileron and airplanes; stick with the ER80S-D2 and completely around the station, finish- locks out twist. Adding the leading edge you’ll be fine. ing each cluster in turn, before moving wrap is the critical step.

3M structural adhesive for metal-to-metal bonding. Only the spar line and end ribs are riveted.

34 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Completed aileron. Despite the length, this Kimball design does not need spades.

In the Kimball shop it is done with the assembly standing vertical in a special fixture. The basic table structure is a stiff glued-and-screwed box. A groove just wide enough to cradle the trailing edge material runs down the centerline of the top surface. A series of hardware store turnbuckles, some strap, a bit of rod, and a few wood plugs secure the aileron to the table. The turnbuckles are carefully adjusted until the assembly is perfectly straight. The leading edge skin is held tightly in place with bungees, and the rivet holes are drilled, de-burred, and dim- pled. Note there are no holes in the interior nose ribs; rivets are not required in those locations. That’s because the skin is bonded as well as riveted, using 3M Scotch-Weld 2216 structural adhesive. To promote adhesion, the nose rib and spar flanges are roughed up with a coarse grit wheel, as are the matching areas on the inside of the skin. The adhesive is mixed, and a bead is spread on all the flanges. The skin wrap is placed, pressed into the adhesive, and Clecoed. Solid rivets are squeezed along the spar line, and blind rivets are pulled in the end nose ribs and a few awkward locations. Squeezed out adhesive is wiped away before cure. The result is light, strong, and stiff, suitable for even the baddest biplane. See you next month! J

KITPLANES May 2014 35 Straight and Narrow Wheel alignment 101. By Dave Forster

36 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes It was my cousin’s first flight in a light aircraft, and he was clearly enjoy- Camber ing himself. As the mainwheels touched the pavement in one of my rare greaser landings, I was feeling pretty pleased, too. We had spent the afternoon playing in the summer sunshine and I was still basking in the glow as the airplane slowed on the runway. But when the third wheel touched down, suddenly, all hell broke loose. In an instant, the calm, cool and col- lected pilot (me) transformed into a ter- rified passenger, gripping the controls, pushing the opposite rudder and brake, and basically just going along for the ride as the airplane ignored the control inputs and taught a lesson about who Checking the camber. was really the master. As the dust settled, my cousin looked on tire life, especially when operating so once one is adjusted, it will be neces- over and said, “Is it supposed to do that?” from pavement. sary to go back and check the other. Among the various measures of wheel Are We Aligned? alignment, toe-in has the greatest effect Adjusting Camber As it turned out, a balky tailwheel was the on how straight an airplane will track. To adjust camber, you will need: primary culprit of our off-airport excur- Fortunately, there is an accurate way 1) A 12-inch or longer bubble level, or sion into the weeds, but I had known to check wheel alignment, thanks to the 2) A 12-inch or longer straightedge and for some time that the wheel alignment availability of inexpensive laser levels. If a digital level. was making landings more problematic you are shopping for a laser level for this 3) Square tube or angle sufficiently long than they should be. Of course, tail- purpose, look for one which projects a to span the cockpit rails (low wing draggers are known for a willingness to vertical line. aircraft). swap ends, but even with tricycle gear The first step in checking wheel align- Adjusting camber is much quicker airplanes, wheel alignment can make the ment is to check and adjust camber. than adjusting for toe-in because it is difference between a tiger and a pussycat Once the camber is set, toe-in can be not necessary to mess around with the when it comes to keeping things pointed adjusted. Note that placing shims for laser. Place the bubble level/straight- straight. It also has a substantial impact camber may affect toe-in and vice versa, edge vertically against the side of the wheel and look at the bubble (or read- out on the digital level) to see if there is positive or negative camber. Using shims, adjust for zero camber. Some hangar floors are not very level. To adjust for this, place the bubble level across the top center section of the fuselage between the wings (high wing) or across the cockpit rails (low wing). This will tell you if the airplane is sitting level from side to side on the floor. If span- ning the cockpit rails, it will be necessary to use a longer bubble level or a straight piece of angle or square tube as a base for the shorter bubble level or digital level to sit on. The digital level is an advantage here, as it makes it easy to do the math to account for an uneven floor, rather than relying on an eyeball’s account of how Laser levels can be purchased for a reasonable cost at a number of tool supply houses. far the bubble level is off center.

Photos: Dave Forster KITPLANES May 2014 37 Checking the fuselage level. A white wall will help show the laser—make sure the aircraft centerline is perpendicular to the wall.

Adjusting Toe-In measurements will be. For the align- Doing the Math To adjust toe-in using a laser level, you ment done for this article, the distance Anything more than 2 degrees is a lot of toe- will need: between the mainwheels and the wall in (or toe-out). Determining the degrees of 1) A dim hangar. was about 20 feet. toe-in or toe-out requires some trigonome- 2) A flat wall in front of the aircraft. try. I still remember my grade 9 math teach- 3) A laser level that can project a verti- Step 1: Position the aircraft er’s accent as she pronounced “SOHCAHTOA,” cal line. Place the aircraft so that it is pointed which is the memory aid for determining 4) A separate bubble level, preferably straight at a wall. The aircraft should be the angle of a triangle; Sine=Opposite over 24 inches long or longer. as perpendicular to the wall as possible. Hypotenuse, Cosine=Adjacent over Hypot- 5) A stack of 2x4 wood. You can confirm that it is perpendicu- enuse and Tangent=Opposite over Adjacent. 6) Masking tape and a pen. lar by measuring from the leading edges The triangle formed by the floor tape in 7) A tape measure. of each wing to the wall; the distance front of the wheel and the two wall tapes 8) A jack or other means to raise and should be the same. (the wheel and the centerline tape) can be lower the aircraft. calculated using a spreadsheet or scientific 9) Hand tools to install and remove Step 2: Find the extended centerline of calculator and SOHCAHTOA. However, for a shims. the aircraft on the wall ballpark guide, the following can be used: 10) A plumb bob (may be needed for Place the laser level against the wall, If the distance to the wall is 10 feet (120 the tail on nosewheel aircraft). pointing at the center of the aircraft. inches) then: Confirm that the laser is perfectly level The distance between the airplane from side to side by holding the 24-inch Toe-In/Out (in.) Degrees and the wall is not too critical, but the bubble level vertically in front of the 0.5 0.24 farther away it is, the more accurate the laser. If the laser is level, then the laser 1 0.48 2 0.95 5 2.39 10 4.76 If the distance to the wall is 20 feet (240 inches) then: Toe-In/Out (in.) Degrees 0.5 0.12 1 0.24 Toe-Out 2 0.48 5 1.19 10 2.39 —D.F.

38 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes WALL Landing Gear L A Wall tape for S extended centerline E R Structure While many landing gear systems are easily adjusted with shims, this is not possible for all of them. Floor tape for extended centerline Some landing gear systems are designed so that the gear and axle are all one piece. This means there is no opportunity to adjust any of the alignment parameters. This can be a good or bad thing; if it was constructed correctly right from the start, it should be fine. However, if it bends over the course of some firm landings, it may not be possible to adjust back to where it needs to be, leaving replacement or putting up with it as the only options. However, many gear systems attach the axle with bolts, making adjustment possible Finding the centerline on a wall. with shims or washers. The best kind of adjustment is with a line will be perfectly vertical and will taildraggers, this is pretty easy. For shim which covers the whole base of the bisect the 24-inch bubble level. If the nosewheel aircraft, it might be nec- axle. For example, Grove Aircraft Landing laser is not level, it can be shimmed with essary to drop a plumb bob from the Gear Systems supplies camber and toe-in small pieces of paper. Alternatively, if tail and shift the laser left or right to shims. This distributes the load evenly your laser comes with a tripod holder, estimate the center; the nosewheel across the mating surfaces but does subject you can simply adjust the tripod. How- gear will probably block the laser from the mounting bolts to uneven stresses as ever, don’t rely on the bubbles on the hitting the tail and/or tail plumb bob. they will no longer be passing perpen- tripod to confirm that the laser line is Depending on how bright the laser dicularly through the parts. Washers can perfectly vertical; only the 24-inch bub- is and how dim the hangar, it may be be used in place of shims, but result in ble level will confirm that for sure. helpful to tape some white sheets of the loads being carried against only the Move the laser along the wall until paper on the airplane to make the laser washer surface and not distributed along the vertical line projected against the line stand out. the entire face of the mating parts as a shim aircraft follows the centerline of the Once the correct laser position is would do. For this reason, shims are better aircraft from its nose to its tail. For found, place a piece of tape on the wall than washers, and both need to be used in moderation. In some cases, even light washers result in too much of an adjustment, so a washer-like shim can be constructed from sheet aluminum. If it is necessary to stack more than a couple of shims or full size washer equivalents, it might be a good idea to revisit the geometry of the gear system and correct the problem where it started. —D.F.

Washers make good temporary shims as you experiment with finding the Confirm the laser line is vertical. Mark the floor tape centerline. correct alignment.

KITPLANES May 2014 39 directly behind the laser and mark the center of the tape with a pen. This is where the extended centerline of the aircraft meets the wall and is the center point of measurement for the extended track of each wheel. Also place a piece of tape on the floor about 18 inches in front of the wheels so that the vertical line from the laser bisects the tape. Draw a pen line on the tape that matches the laser line. This is the center of the aircraft projected onto the floor, which will be used to measure how far each wheel is from the centerline. (Due to landing gear movement and lean of the aircraft, Marking floor tape for toe-In. it is possible that the wheels might not actually be the same distance from the and against the middle of the wheel. tape that matches the laser line. Do the airplane centerline.) This makes the laser point in the same same thing on the wall tape. direction as the wheel is tracking. Place Step 3: Project the track line a piece of tape on the floor about 18 Step 4: Project the track line of the of one wheel inches in front of the wheel so that the other wheel Stack the wood beside the wheel so that vertical line projected from the laser Repeat Step 3 for the other wheel. The the laser level can be placed on the wood bisects the tape. Draw a pen line on the floor tape for each wheel and for the centerline (Step 2) should be the same dis- Toe-In Theories tance in front of each wheel. There are different theories about whether an airplane should have toe-in, toe-out or Step 5: Measure toe-in none at all. Starting with the left wheel (or the right; In a car, some toe-in for a passenger vehicle is considered desirable, as it helps to keep the it doesn’t matter), measure the distance car going in a straight line. For airplanes, there are different groups who will argue passion- between the floor tape in front of the left ately about whether toe-in is a good idea or not. wheel and the floor tape for the aircraft The argument in favor of toes in goes like this: With toe-in, if a gust of wind catches the centerline. Do the same thing for the wall airplane and points it slightly to one side, the downwind wheel is now pointed more off a tape for the left wheel and the wall tape straight line than the mass is traveling, therefore causing more rolling resistance. At the for the extended aircraft centerline. If same time, the upwind wheel is pointed more in the direction of travel, providing less roll- the wall tape measurement is bigger than ing resistance. Because the upwind wheel has less rolling resistance than the downwind the floor tape measurement, then the left wheel, the upwind wheel moves forward more freely, thereby naturally correcting the wheel has toe-out. If the wall tape mea- effect of the wind gust. surement is less than the floor tape mea- The argument in favor of toe-out (especially for tailwheel aircraft) goes like this: When a surement, then the left wheel has toe-in. If gust of wind catches the airplane and causes it to pivot to one side, it also causes the center the two measurements are the same, then of mass/inertia to move more onto the downwind wheel. This is like skiing or skating, where the left wheel is tracking straight ahead. the weight is mostly on the leg on the outside of the turn, and is therefore more dominant for determining the direction of travel. In this case, toe-out is a desirable state, because the Step 6: Repeat Step 5 for the other downwind wheel will be pointed towards the downwind side of the aircraft. As the down- wheel wind wheel is more dominant, it will tend to turn the aircraft back downwind. As the aircraft turns back downwind, the weight will shift back to being more equally distributed among Step 7: If changes to the toe-in or the wheels, so the net result is self-correcting. toe-out are necessary, jack up the There is also a third camp, which says that all of this is hogwash for airplanes and the best wheel and install the shims situation is where both wheels are pointed straight ahead all the time. Unfortunately, by jacking up the plane, Each group will argue for their position and will supply real world examples to support the gear geometry will probably change. their cause. It seems that the only way to know for sure for a given airplane is to just try It will likely be necessary to roll the air- it out. However, all groups seem to agree that having the wheels pointed straight ahead plane back out of the hangar and then is a pretty good alternative and not likely to lead to any adverse behavior. In my personal straight back into the measuring loca- experience, straight ahead seems to work well. tion so that the gear can move back into —D.F. its natural position. Placing alignment

40 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes WALL Camber and Caster When it comes to wheels, camber is not a trotting horse and caster is not a friendly ghost. Along with toe-in, these attributes describe the angle that a wheel makes relative to the body or airframe it is attached to. Mark the laser line on the floor Camber is the amount by which the and on the wall. wheel departs from vertical. If you placed a straightedge vertically against the outside of the wheel and looked at it from the front of the airplane, the degree of camber is the L A degree to which the straightedge leans left S E R or right. If the top of the straightedge is closer to the fuselage than the bottom, the wheel has negative camber. If the top of the straightedge is farther away from the fuselage than the bottom, then the wheel y” x” WALL has positive camber. For most aircraft, there seems to be a consensus that zero Wall Tape Projected Centerline camber is a good thing. Caster is the way in which a wheel pivots z” Toe Out=y when it is turned. It is the angle to which Degrees= Tan (y/z) the steering pivot axis is tilted forward or Measure the distances and rearward from vertical, as viewed from calculate the math. Floor Tape the side. If the wheel has zero camber and the straightedge was inserted vertically x” through the middle of a tire, then if the straightedge pivots in place when the L A wheel is turned, there is zero caster. If it is S E R necessary to tilt the top of the straightedge back in order for it to pivot in place while Centerline the wheel is turned, then there is positive caster. If it is necessary to tilt the top of tapes on the floor to mark the positions weight is transferred from the wings to the straightedge forward in order for it to of the wheels will help, but it will still be the wheels. Although the laser method pivot in place while the wheel is turned, necessary to go back and check all of the of wheel alignment is very accurate, the then there is negative caster. Positive laser lines and tapes whenever the air- nature of the changing gear geometry caster helps straight-line stability. For most craft is moved. means that any adjustments will simply aircraft, caster is not something which is Step 7 is the tedious part, as it means get the alignment into an average ball- easily adjusted. repeating everything from Step 1 when- park; don’t sweat 1/8 inch on the wall if Toe-in is the degree to which the wheels ever anything is changed. This can take the extended toe-in changes by 1 inch point in or out. If you placed a straight- a long time as you try different shims to over the course of a landing rollout. edge horizontally against the outside of see what the effect is. Keep notes as you After trying various combinations the wheel and looked down on it from go along and you will soon see a rela- of toe-in, toe-out, and camber with above, if the front of the straightedge is tionship develop between shim thick- flight tests in between, I determined closer to the extended centerline of the ness and the amount of movement of the that for my SeaRey, 0 degrees for each aircraft than the back of the straightedge, laser line on the wall. was the best place. The difference in then the wheel has positive toe-in. If Wheel alignment can change with runway manners between the tests was the front of the straightedge is farther load on the aircraft to the extent that impressive; the same airplane could be away from the extended centerline of the the landing gear moves with load. This a handful or sweet as can be, simply by aircraft than the back end, then the wheel means that a heavily loaded aircraft adjusting these parameters. has negative toe-in (otherwise known as might have different alignment than a Fortunately, my cousin is outgoing “toe-out”). Toe-in (or out) has a substantial lightly loaded one. It also means that and willing to fly with me again. All the impact on how well an airplane will track during the landing rollout, the align- same, maybe I’ll just stick to the water down the runway. J ment can change as more and more next time. —D.F.

KITPLANES May 2014 41 First Flight Surprise!

Canopy–closed and latched? By Mike Newall

I have flight-tested a few airplanes after annuals and rebuilds, but so far, I have only done two first flights. The first one was our RV-7. Apart from warm CHTs on a brand new motor, everything was as expected, and we easily progressed through the fly-off stage and enjoyment of the new plane. The second first flight was another story. Eighteen months ago, I was approached by a guy who was about to buy a new, unflown RV-12. He asked if I could do the initial flight and subsequent flight testing required by the English regulatory system. After establishing who had built the airplane As designed, the RV-12 latch handle can only be turned one direction, and will positively and who had signed it off, I agreed to latch in the hook. If it is installed in reverse, it will still move correctly, but only the “nub” become involved. on the end will engage the latch hook.

42 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes In the author’s RV-7, the latch handle is almost symmetrical on either side of the shaft, so it will latch in either direction (although one direction is more secure). In the RV-7, there are additional latches on the sides if the roll bar latch isn’t closed.

the naked chaps swapping balloons, that In this view, the asymmetry of the latch is apparent—if installed 180 degrees out, only a small portion of the latch handle will engage the latch hook on the roll bar. is how I was until I could come up with a system of quickly swapping hands to The RV-12 in question had been built inspector, away from the owner. After attend to all needs.) to a high standard, with a polished fin- again going through everything, we I was soon on final, the landing ish and was allegedly ready to go—apart finally agreed that it was ready to test. was fine, the heart rate reduced, and from a couple of minor snags. Time The paperwork was done, the weather I taxied in. to get curious, I thought. The airplane was fine, the GoPro attached, we were The big question, of course, was why seemed to have been sold and delivered good to go. the canopy popped open, and why it by road in a bit of a hurry; I think the To say that Van’s designs and pro- wouldn’t re-latch in flight. On fur- new owner was naturally keen to get duces good products is an understate- ther questioning, the new owner said, going and agreed with the builder to ment; the RV-12 flew beautifully—a “Oh, yes I swapped the handle around look at some of the minor jobs after tak- real sweet little airplane. because it was stiff.” ing delivery. I wanted to go through the After around 15 minutes of gentle Of all the small things that you airplane with the new owner’s inspec- expansion of the parameters, I decided would have taken for granted, it was tor to ensure that these items weren’t an to take it up to a medium speed (nowhere one of these that bit my tail: On inspec- issue and would easily be solved. near Vne) to check for straightness, tion, the overlap when 180 degrees out First was a lack of fuel pressure indi- vibrations, etc. was adequate on the ground, but insuf- cation, and a similar snag on charging. At that point, the canopy came open! ficient when flight loads pulled the can- Neither was a major issue and both were It does concentrate the mind as you opy up. To say he was a little sheepish easily solved. But the fuel tank had not are short of two hands—one to grab the was an understatement. been calibrated. The owner said that it handle, one to grab the papers, one to Anyhow, the rest of the testing went could be done later and we could fly it hold the stick and the fourth one to con- fine, and he is now happily flying a super now by just putting in a known amount trol the cursed Rotax sprung throttle. nice RV12 around the skies of England. of fuel. Err, no, I thought—let’s go ahead Anyhow, I ended up with one hand Sometimes, it is the startlingly unob- and calibrate it now. on the canopy handle and one on the vious things that can contrive to cre- So, we started through the calibra- stick, with the throttle closed and ate a problem. Many an airplane has tion process and almost immediately, locked. Hmm…OK, we are safe—how- been lost on a first (or second, or third) we were awash with fuel. There was no ever, we are gliding and the canopy does flight because the pilot was startled by gasket under the sender in the tank. float a long way up. Attempts to get it a minor issue that really didn’t affect Oh Boy! Now I was beginning to closed and locked proved futile—time the ability to stay aloft. In the end, the reconsider my offer of help. to keep flying the airplane and figure old saying, “Fly the plane,” is always the However, we sorted out the prob- out the problem on the ground. (If you best thing to remember—and always lem, and I had a long chat with the have ever seen the balloon dance with the best policy. J

Photos: Marc Cook, Joe Blank and courtesy Van’s Aircraft KITPLANES May 2014 43 Panel Upgrades Part 1–planning the project. By Stein Bruch

Building an airplane is just part of There are really only three main rea- replace it with an EFIS like the small the fun for homebuilders. After build- sons for upgrading your panel or avionics. Dynon, GRT, or MGL units. This is a ing comes flying, then maintaining, and First, the equipment may be outdated. very big bang for the buck, as you actu- eventually upgrading—that is if you Second you want to take advantage of ally save weight, along with gaining keep the airplane long enough before newer technology, added functionality, a pile of functionality. It’s a relatively becoming a repeat offender and decid- new features, or you just want it! Third, simple upgrade to remove a round ing to build the next one. you may be upgrading from VFR to IFR. instrument and put another into the After some period of time, there will Considering that equipment isn’t truly same hole. Wiring is minimal (typically no doubt be a number of widgets, gad- and absolutely outdated until (a) it is power, ground, and maybe an audio gets and other items that catch your eye. no longer legal, or (b) it no longer func- wire) and simple pitot/static connec- These can range from the rather simple tions as needed, or (c) it costs more to fix/ tions are made. This type of upgrade and mundane to the latest and greatest maintain than replacing with new, it’s my can typically be done in the span of a large-sized touchscreen EFIS. We are experience that most of us fall into the long weekend, or a couple weekends. lucky that in this industry, we’ve actually second or third category. seen a unique phenomenon: the price of There are two things that absolutely avionics going down, while functionality must be done before anything else. and features increase at a very rapid pace. First, you must decide what you’re Realizing that avionics constantly going to upgrade, then you need to change, you likely installed something decide how much of it you’re going to that you were satisfied with at the time change. Those two items will drive you built the plane. But now that you’ve the entire project. Deciding what to flown the airplane awhile, there’s a good upgrade is sometimes easy and some- chance you’re ready for an upgrade. Over times difficult. I’ve broken this down the next several months we will explore into a couple different areas, which the sometimes simple, and occasionally range from simple to more difficult. challenging, process of upgrading the instrument panel in your aircraft. Major or Minor Surgery? Adding an angle of attack system is a This month we’ll look at the first step. On the simple side of things, it could common upgrade that can be done in a We’ll simply call this, “Where do I start?” be easy to remove a vacuum system and weekend of concentrated work.

44 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes One of the simplest upgrades you can make to an airplane with steam gauges is the addition of Dynon D1 portable EFIS. Simply remove a round gauge, clip in the mounting bracket, attach the D1, and you’re done!

Remember, removing the old stuff and In addition to the transponder panel or intercom, swapping out incan- plugging holes or vacuum pump drives upgrade, adding an ADS-B receiver to descent navigation/landing lights for a can take a number of hours on its own, your plane is another popular upgrade newer LED type, adding a safety trim so take that into account. that is relatively painless and not terribly device, and installing a simple EFIS like Other relatively simple and popular expensive (in the world of avionics any- the Dynon D1/D2/D6/D10 or Aspen upgrades are trading up to a new mode way!). Remember that in order to add a Avionics EFIS. S/ES transponder, which gives you part receiver, you’ll also need to add another Once you’ve determined that your of the solution to utilize ADS-B in your antenna to the bottom of the aircraft. upgrade will involve either a little bit aircraft. There are a number of alterna- Typically it’s similar or identical to the of stuff or a lot of stuff, you need to get tives, depending on what you currently transponder antenna you already have down to the nitty gritty of exactly what have installed, but it could be as simple on the plane, but located a distance from you’re going to do. If all you want is to as sending your current transponder to it. You’ll need to run some basic coax replace your attitude indicator and the manufacturer for an upgrade, plac- cable to that antenna, mount the box directional gyro with something digital, ing something else into the same tray somewhere in the plane, and hook up that would be considered minor surgery. with minimal wiring changes, or adding some basic wires (power, ground, typi- If you’ve decided to rip out the entire a completely new transponder in place cally a couple communication interface panel of round analog stuff and go with of an old one. Any of the aforemen- lines, and probably a GPS line). There are new flat screen digital panels, that would tioned options are yet again typically a portable units out there which take even be considered major surgery! Many long weekend project. less work—sometimes they are as simple times the line between minor and major as plugging in a power plug (or wiring it is rather gray, but basically if you plan on to ship’s power) and using wireless/Blue- doing anything other than the simplest tooth to your GPS or tablet. “remove and replace,” most of the time Other popular upgrades that fall into it’s just as easy to have a new panel cut the minor category are things like add- (only hundreds of dollars from many ing a smoke system or autopilot, mount- shops) and replace the entire thing in ing a tablet to the face of the panel or one fell swoop. We’ll discuss the partic- side of the plane, upgrading your audio ulars of that process in our next article.

You can add ADS-B capability to a typical EFIS with either a portable Garmin unit like the GDL 39 or the remote-mounted version of the same box, the GDL 39r.

Photos: Courtesy the manufacturers and Stein Bruch KITPLANES May 2014 45 Some aircraft are designed with removable instrument panels. This RV-8 panel can be Although many modern digital autopilot removed in about five minutes and either upgraded or replaced with a new version with servos look alike, and many can use the new goodies for the pilot. same mounting brackets, they are all electronically unique and must be used with Which Stuff? some digital instruments (it’s likely you the specific company’s controller or EFIS. By now you probably know if your proj- have at least some digital engine instru- ect is going to be a weekend job or some- ments) of a certain brand, it makes sense mentioned except Dynon. Most com- thing much more involved. The next step to look at the same brand for upgrading panies are now offering their own inte- is figuring out exactly which equipment since you’ll likely be able to use many of grated autopilots, so keeping an existing to purchase. There is no absolute answer, the same probes and sensors, wiring, and autopilot, upgrading an existing autopi- but there are some general guidelines to even connections. If you have something lot, or replacing an existing autopilot are assist you with this task. like a GRT EIS module, it will easily more options to consider. Most people want to know which attach to a new GRT EFIS. If you have If you have a GPS (portable or panel brand of equipment is best. There’s no an older generation Dynon EMS, the mount) installed, it will likely interface absolute answer for all budgets and probes/sesnsors/wiring will easily plug with any popular EFIS. As far as radios airplanes, but I can say that the most into their new system, as well as equip- go, if you have anything that is older popular EFIS systems on the market ment from AFS. The same goes for MGL technology than a radio like an SL30/40 right now (at least for sport aircraft) are and even some Garmin equipment. (Narco, King, and TKM come to mind, Advanced Flight Systems, Dynon Avi- If you have an autopilot installed, but there are others), it’s likely it can’t be onics, Garmin, Grand Rapids Technol- some brands will work with existing connected to your EFIS. In this situa- ogies, and MGL. The first four make up servos, but many will not. (You usually tion, a radio upgrade might be consid- the bulk of the market in the U.S., but can’t mix and match servos from one ered a valuable addition. MGL is quite popular abroad. company with an EFIS or controller For audio panels, there are really only One thing to consider is what brand from a different company). Standalone two viable choices in the market. PS of equipment is already installed in your autopilots like TruTrak and Trio will Engineering has long been the premium plane. For example, if you already have interface with all brands previously leader in this space, but Garmin also

Updating an instrument panel with a modular design, as in this Tecnam, is structurally simple and can greatly increase the utility and capability of an aircraft.

46 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes has some new offerings that are quite competitive. Regarding intercoms, the choices are much broader and there are many options, depending on what your upgrade entails. I might add that if your upgrade includes more than one radio, you should also consider getting a full- blown audio panel. Yes, you can kludge together a simple intercom with various switches and wiring to sort of make it work, but all things considered, the audio panel is a better investment of your money and time if you have more than one radio. The last consideration for specific equipment depends on exactly what you are going to do with the aircraft. A very popular upgrade is to add something like a certified WAAS GPS to make the aircraft IFR legal. In order to do that, you must also add equipment that will work well with it. That means you can’t use the smallest and cheapest boxes (like the Dynon D1/D2) because interfac- Upgrading to an entirely new panel, as in this RV-10, starts with laying out the new panel ing those boxes will either make things using either pencil and paper or a CAD program. A major panel upgrade can affect wiring difficult to use, or it can’t be done at all. throughout the airframe, and involve significant labor. The same goes for full-functioning autopilots (if you want them to do some- yourself) to many thousands if you hire • Additional COM Radio: $1200 to thing like fly a coupled approach using it out. We’ll cover some of the DIY por- $1800. NAV/COM radio: $3500 the aforementioned IFR box), ADS-B tions and possibilities in the next article. to 4000. receivers, Mode S transponders, NAV Here are some popular upgrades and • Audio Panel: Upgrade from inter- radios, etc. what a generalized budget might be. com. $750 to $2500. Prices listed are for new equipment; • Smoke System: $750 to $1000. How Much? obviously you can occasionally find used • Tablet Computer: $250-$800. Now for the big question: How much? equipment for less. • New Panel: Custom cut. $150-$500. I’ll do the best I can to give you some • ADS-B Receiver: $1000 + plus $50- Note that with all of the aforemen- basic swags as to what various upgrades $150 for cables/antennas. tioned upgrades, we did not include the might cost from a materials standpoint. • Transponder: Upgrade/replacement price of any labor. If you do it yourself, Labor can range from zero (if you do it to mode S/ES. $1200 to $2500. labor can be greatly reduced. However, • IFR-Certified WAAS GPS: GPS sometimes purchasing things like pre- only, $4000 to $6000 depending fabricated wiring harnesses (from $100 on brand. to $2500) can be cheap insurance and • Full IFR Navigator: Upgrade/ save huge amounts of time. Labor for addition to Garmin 430W, GTN- the physical installation provides the 650/750 or Avidyne. $7000 to biggest return on your own sweat equity, $14,000. and we’ll cover this topic in detail in • Autopilot: Single axis from $750, future articles. dual axis from $1650 to $3000. Upgrades are almost universally The Gemini PFD from Tru Trak is but one • Simple EFIS: Plug into standard fun, sometimes challenging, but ulti- of several compact “six-pack replace- 3-inch instrument cutout. $1200 mately very rewarding. Even the small- ments” available in today’s market. to $2200. est upgrade, like adding a Dynon D1 Dynon, GRT and MGL all have simple • Full-Featured Large-Screen EFIS: EFIS, can add value to your aircraft electronic gyro and air data packages that provide a quick and simple upgrade With synthetic terrain, GPS, EIS. and reduce your workload, arguably path for a dated panel. You’ll never have $4000 to $5000 single screen, $6500 making your job as a pilot easier and to buy a vacuum pump again. to $12,000 dual screen. increasing safety. J

KITPLANES May 2014 47 maintenance matters Look beyond the starter motor to solve starting problems. My darn plane won’t start. Do I need trickle charger is a great solution to this an item few amateur mechanics seem a new starter? Well, maybe—but prob- problem for infrequent flyers. Of course, to have, but one that is easily affordable ably not. Tracking down starting prob- more flying is an even better solution. In for 12-volt systems. Share one between lems requires thinking about the entire cold weather, preheating your plane and some friends or your EAA chapter if you starting system. That system includes keeping the battery fully charged will like, but get one. Then check your bat- the battery, the starter switch and relay, likely eliminate at least 90% of all start- tery once a year or whenever you are the wiring (and connectors), and finally ing problems. As more people come to having problems. Remember, batteries the starter itself. A weakness anywhere rely on smaller batteries for their planes, don’t last forever. A good battery owes in the system can bring the whole start- it is even more important than before you three or four years of normal service. ing process to a grinding halt. Let’s look that this vital part of the starting system After that you are on your own. Especially at each component and how it plays an gets the care it deserves. if you regularly fly IFR, plan on getting a important role in the starting process. A fully charged battery should pro- new battery every three years. But first, a special safety note: When- duce close to 13.0 volts with a minimum ever you are testing the starter system, of 12.6 volts (12-volt system). Unfor- Battery Cables and Connectors be sure that everyone is well clear of the tunately, voltage doesn’t tell us much Those big wires that go from the bat- propeller at all times. It is easy to get about the ability of a battery to sustain tery to the starter relay and the starter distracted by the details of the trouble- a heavy load. That requires a load tester, are very important and a frequent shooting process and forget this basic safety rule. Please be extra careful not to forget. It is impossible to overstate the danger of a spinning propeller to life and limb.

The Battery A weak battery that is either too old or not fully charged is the most likely culprit when an airplane is hard to turn over. There is easily an article’s worth of things to say about batteries alone (and Bob Nuckolls is covering those in his Practical Electrical series on these very pages), but a review of a few basic points seems in order. Batteries need to be kept fully charged. With more and more flyers struggling to log even 50 A strong kickback broke the casting of this lightweight Sky-Tec starter. All starters can hours per year, it is often several weeks be broken by kickbacks, but lightweight starters are somewhat more vulnerable to between flights for many people. A this problem.

Dave Prizio is a Southern California native who 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 he is helping a friend Dave Prizio build a fourth, an RV-8. When he isn’t building something, he likes to share his love of aviation with others by flying Young Eagles or volunteering as an EAA Technical Counselor. He is also a member of the EAA Homebuilt Aircraft Council.

48 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes source of starting trouble. They look are the right size. As an amateur builder so robust and reliable that it is easy to you can use any size wire you want, but take them for granted, but corrosion at there is a best size, depending on your the ends of these cables can easily bring particular installation. First of all, always the whole starting system to its knees. use aviation-grade copper wire. Weld- After you have checked your battery, if ing cables or other non-aviation wire you still have starting problems, take may carry the load, but they do not each cable connection apart and clean always have insulation that will prevent it right down to the bare metal. A stiff them from emitting toxic smoke in case wire brush will usually do the trick, but of a fire. Aviation wire offers that protec- don’t be afraid to use course sandpaper tion. The size of your wire will primarily if you have to. Be sure to remove 100% depend on how far the battery is from of any corrosion you may find. It is best the starter. If the battery is mounted on to simply replace any corroded nuts or the firewall, #6 AWG wire will work. For lock washers. When everything is clean, larger engines, especially fuel-injected reinstall each connection and tighten it ones that may require more sustained appropriately, depending on its size and cranking, it is better to upgrade to #4 the manufacturer’s recommendation. AWG wire, even if the battery is very Please note that battery makers will usu- close. If your battery is in the cabin, the ally have a specific torque for battery length of the wire run becomes the key posts. Over-tightening can be worse factor. With a total wire length of not than under-tightening, so be careful. more than 12 feet, you may use #4 AWG This Carbon Cub with its special O-340 engine is fitted with a Hartzell X-Drive Similarly, starter makers will have rec- wire. Beyond that, you must increase lightweight starter. ommended torque numbers for the the wire to #2 AWG, to a maximum wire mounting bolts and the wire terminal. length of 20 feet. If you use the fuse- calculation. Sky-Tec has a handy table to Find out what the numbers are for your lage or cage as the ground conductor, determine wire size (http://skytecair.com/ starter to be safe. you do not need to count the length of wire.htm) or you can refer to FAA publi- Just as important as the condition wire saved by using the cage as a ground cation AC 43.13-1B. of the battery cables is to be sure they conductor in your wire length calcula- Remember that the ground strap tion. If you are running a ground wire is a vital part of the electrical connec- JUMPER separately from the fuselage or cage, tion from the battery to the starter. If Use when left mag is Retard Breaker you will need to count the length of both you are using the airframe as a ground mag or has impulse coupling the positive and negative wires in your in your plane, there must be a good 1

R 2 L UR 5

S GRD

BO 4

BAT 3

With the master on you should see 12 volts between posts 3 (BAT) and 5 (GND). With the starter switch turned to Start, you should see 12 volts between 5 and 4 (S, for Start). If you isolate the switch, you can measure resistance between 3 and 4. This should be open when the switch is off The jumper between the large starter wire post and the smaller post on the solenoid and less than 0.2 ohms when the switch is is needed to allow single-wire installation (most common). If you do not have this wire, turned to Start. you should install one to avoid the need for a separate wire to the solenoid.

Photos: Dave Prizio, courtesy Hartzell Engine Technologies KITPLANES May 2014 49 clean electrical connection from the engine through the ground strap to the engine mount and to the airframe. Cor- rosion, paint or loose bolts anywhere in this chain can increase resistance and reduce the power of the starting system. The same applies if you are running a ground wire directly to the engine. The connection must be metal-to-metal and corrosion-free.

Starter Switch and Relay With battery cables properly sized and connections cleaned and tightened, the plane should turn over easily, but it doesn’t. Now what? With a good battery and wires, you should at least hear the starter relay click when you Experimental airplane builder/mechanic Ed Zaleski checks the voltage coming to the turn the key to Start. If you do not, look starter relay. The large wire from the relay to the starter has been disconnected for safety. to the starter switch and wiring for a problem or possibly the starter relay Check the resistance in the wire from starter terminal, too. If you do not, you or the starter itself. If the starter has a the switch to the relay and the wire likely have a bad starter switch. You can burnt smell to it, you likely need a new from the switch to the main bus with an also check the switch with your ohm- starter, but you will still need to find ohmmeter. You should see very low to meter, but be careful not to run 12 volts out why it got that way. no resistance (0.2 ohms max.) in these through the leads when the meter is in If the starter looks and smells nor- wires. If there is any significant resis- the ohm setting. It could damage your mal, connect a voltmeter to the positive tance noted, first check, and if needed, meter. With the key in any position but (small) post on the starter relay. Con- replace the connectors at the ends of Start, there should be an open circuit nect the other lead to ground. If you do the wires, or replace the wires if this between the BAT post and the Start not see 12 volts when you turn the key doesn’t solve the problem. Next check post, but when you turn the key to Start, to Start, you have a problem with the the switch itself. If your wires are good, the resistance should go to zero. If your starter switch or wiring. From here it is you should have 12 volts when checking switch is bad, simply replace it. a matter of tracing the problem through from the BAT post on the ignition switch If the starter switch and wiring all the system until the faulty component is to ground. Then, when you turn the key check out, you may have a bad starter found and repaired or replaced. to Start, you should see 12 volts at the relay. To test the starter relay, first disconnect the large wire that goes from the relay to the starter. With this disconnected the starter motor cannot be activated by turning the key to Start. It is much safer this way. Have a helper turn the key to Start and listen for the relay to click. There should be a good solid click every time the key is turned. If there is not, and you have already checked to see if you are getting 12 volts at the wire from the starter switch, you should try one more thing before you replace the relay: The typical starter relay will have two small posts on the body of the relay. These are different from the two large posts that hold the battery and starter wires. This older Prestolite starter has been disassembled to show the parts. The Bendix drive It is possible that the wires to the small and the brushes can be serviced by an Experimental owner/mechanic, but most people posts have gotten switched somehow. discard this type of starter to save weight and maintenance headaches. Remove these wires and switch them

50 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes The brushes in a Sky-Tec starter can be replaced, but it is seldom necessary to do so between engine overhauls. At overhaul time it is best if the whole starter is rebuilt or replaced. to the other post and see if that doesn’t desired click when you do this, it is time solve the problem. to get a new relay. If you are still not getting the results If the relay makes that nice click when you need, it is time to remove the relay. you turn the key, but you are still hav- Remove the wires from the relay and ing hard starting problems, there is still unbolt it from the firewall. If there is cor- another test you can do. Without even rosion between the relay and the firewall, removing the relay from the plane, and clean that up and see if that helps. If there with the wire from the relay to the starter is any doubt about the ground connec- still disconnected, check the voltage at tion between the firewall and the bat- both large terminals. The incoming volt- tery, be sure to attend to that, too. One age should be at least 12.5 volts, and the last test of the relay can be made by con- outgoing voltage when the key is turned necting the positive lead from your bat- to Start should be very close to that. tery charger to the positive, small post, The maximum allowable voltage drop and the other to the mounting tab of through the entire starting system is 0.5 the relay. If you are still not getting that volts, but you should not expect to see

The nose piece of many starters can collect ice, snow and debris. Be sure to keep it clean.

KITPLANES May 2014 51 This Lycoming ring gear has 149 teeth. It is easily identifiable This ring gear off an older O-320 engine has 122 teeth. The by the U-shaped bottoms of the teeth. However, if there is any sharper-cut V-shaped teeth are a good clue to its tooth count. doubt, count the teeth. all of that across the starter relay. If you the wire from the relay to the starter dis- engine down immediately. If your starter have a sufficiently sensitive ohmmeter, connected, it is possible that the relay relay is welded shut (on), the starter will you should read a maximum of 0.2 ohms may work, only to start that rat-t-tat click- start turning as soon as you turn the mas- across the large posts when the relay is ing again when the starter wire is recon- ter switch back on, even without touch- activated. More resistance or less voltage nected. That is because the voltage drop ing the key. Do not attempt to fly a plane than that means the contacts are wearing of the starting operation weakens the with a starter relay that will not shut off. out inside the relay. Time for a new one. pull of the relay enough to allow the con- Note that not all hung starters are caused It is not easy to measure low resis- tact inside to spring back momentarily. by relays welding themselves shut. tance, even with a good meter, so take Another relay problem you may your time, be sure you have good leads encounter occurs when the relay welds The Starter making good contact, and repeat your itself closed (on). This can cause the With most amateur airplane builders measurement more than once. Also be starter drive to remain engaged in the opting for newer lightweight starters, sure to isolate any component electri- ring gear after the key is released. On a the problems often seen with older cally before measuring ohms to avoid Lycoming this can quickly destroy your starters such as the Prestolite starters damaging your meter. In other words, starter and ring gear. On a Continental and others found on many certified air- be sure not to run 12 volts through the this can shred metal and dump it inside craft are less common. New lightweight meter when it is in the ohms setting. your engine, leaving you in need of a starters by Hartzell, Sky-Tec, and others If your relay emits a series of clicks but complete teardown and reassembly. should last the life of the engine (until won’t stay on, the most likely culprits are Often you will be able to hear the strange overhaul). This means that owner main- a low battery or a bad connection or wire sound a hung starter makes, but some- tenance and repairs owing to wear and somewhere in the starting system. With times not. If there is any doubt, shut your tear should be essentially none, except

Hartzell’s E-Drive starter has solid kickback protection, but Hartzell’s X-Drive starter weighs less than seven pounds and is somewhat heavier and more expensive than their lighter has a notably rugged duty cycle. X-Drive starter.

52 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes for keeping connections free of corrosion and keeping the starter nose piece clear of debris. That said, there are a number of problems that do come up as a result of engine kickbacks, improper installation, or abuse. Here are some common problems seen with Experi- mental aircraft starters: • When you turn the key to start, you can hear the motor spinning, but the engine isn’t turning over, or perhaps the starter gear is grinding against the ring gear, but not turning it. Lightweight starters are somewhat prone to having the main casting bent or broken by an engine kickback. A bent or broken starter casting can easily allow the starter to disengage from the ring gear. Unfortunately, the solution is to buy a new starter, and while you’re at it, take a good look at potential starting issues such as your engine’s magneto timing, fuel system, and your starting technique. As a solution to this problem, Hartzell and Sky-Tec now have starters available with kickback protection built in. This extra feature will add about two pounds to the starter, but many people feel it is well worth it. • The most common starting problem is slow turning or no turning of the engine. The most likely causes of this are a weak battery, or loose or corroded connections in the battery cables or the ground strap. Keep your battery well charged and regularly clean and retighten all connections to avoid this problem. Cold weather is especially hard on batteries, so be sure to preheat your engine when the tem- peratures drop and keep your battery topped off with a trickle charger if you don’t fly very often. • If your starter engages and starts the engine, but won’t let go after the engine starts, you have a hung starter. This requires immediate attention. Stop the engine right away. With old-style starters the Ben- dix drive can fail in such a way as to not retract the starter gear from the ring gear (what some people call the flywheel, even though it isn’t). Simply replacing the Bendix drive will solve the problem if the starter motor has

KITPLANES May 2014 53 not been damaged. With a light- together before you know it. A hung starter. Hartzell starters can be weight starter that uses a solenoid starter will quickly follow. cranked for ten seconds at a time to engage the starter gear, a failure • Another possible cause of a hung with a 20 second rest in between of the starter itself will almost never starter with a Lycoming engine is too start attempts for up to 20 times. be the source of a hung starter. Look little clearance between the starter After that, you should wait for 20 instead to the starter relay, which gear and the ring gear. Lycoming has minutes before trying to start the may have welded itself shut (on). a service instruction (SI-1447 B) that engine again. Other brands of start- • When building your airplane you tells you how to shim your starter ers have different, and often more may have noted that there are master to get the proper clearance. A hung restrictive, duty cycles, some only relays and starter relays. The differ- starter will burn up fairly quickly, allowing for six start attempts before ences are important. Master relays are which will be readily apparent by the extended rest. Be sure to check with designed to handle lighter loads for smoke and/or burnt smell coming the maker of your starter to see what long periods of time, but starter relays from it. Time for a new starter and a duty cycle they recommend. Other- are made for high loads of a short new starter relay. wise, internal parts can overheat and duration. If you accidentally use a • Armature damage can result from lead to starter failure. master relay for your starter relay, you excessive cranking, so it is impor- • Another problem that can happen can easily weld the internal contacts tant to know the duty cycle of your with a Lycoming engine is a mismatch between the number of teeth on the ring gear and the pitch of the starter gear. Lycoming engines come with Starter Relay Post-Mortem either 122 or 149 teeth on the ring After a period of hard starting on my RV-8 that lasted close to six months (and became gear. A starter made for a tooth count progressively worse), the engine failed to crank at all while on a long cross-country trip. that doesn’t match the ring gear will Fortunately, the trip was to visit the Van’s factory near Portland, Oregon, and the failure quickly make hash out of both parts. happened just outside their hangar. Also fortunate—they had about a hundred solenoids Always check to be sure your starter in stock. After changing the solenoid, the airplane fired up like it was new, and the trip and ring gear match before attempt- home was pleasant. Ever the curious engineer, however, I couldn’t resist an autopsy of the ing to start your Lycoming engine. failed relay when we got home. Hartzell Engine Technologies now This is the solenoid with the top ripped owns the Lamar line of starters, in addition off. It looks OK from this vantage point, to the other lines it picked up from Kelly but take out the plunger and take a look Aerospace, so for problems with these at the contacts! starters see their web site for more infor- They are nicely pitted—and not mation and technical assistance (www. symmetrically. Note that the contact on hartzellenginetech.com). Their E-Drive the left in the picture was contacting in starters with kickback protection weigh just the corner. After consulting several about nine pounds. Their X-Drive starters old-time mechanics, one came up with weigh about 7.6 pounds, but do not have the most logical explanation when he kickback protection. pointed out that when tightening down Sky-Tec ultra-lightweight starters for the nut holding the cable to the stud, four-cylinder Lycoming engines weigh one needs to back up the stud with a only 6.5 pounds. They have been rede- thin wrench on the stud retaining nut, signed to better withstand kickbacks, or the stud will twist—causing the but do not include active kickback pro- plunger to only touch one corner of the tection. Their HT starters do include flat contact —and causing exactly what kickback protection, but the tradeoff is we were seeing. All of the current has to an increased weight up to 8.9 pounds go through a small contact area, and not and about $90 in added cost. J much can get through. Here is a final picture of the underside A special thanks to Mike Disbrow and of the plunger contact—note the pitting Tim Gauntt of Hartzell Engine Tech- and the fact that it clearly rotates during nologies for their assistance preparing its life. The flat edges of the stud contacts this article. For more information see can’t rotate, and the sharp corner causes Hartzell Engine Technologies at www. the tiny little burned spots. hartzellenginetech.com, or Sky-Tec Fly- —Paul Dye weight Starters at www.skytecair.com.

54 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Home Shop Machinist DIY safety wire drilling. Long-time Kitplanes® subscriber and former Taylorcraft owner Tom Hillard of Michigan suggested a column on drilling small holes, specifically safety wire holes in bolt and screw heads. Tom notes that although many Experimental aircraft are flying with metric engines (Rotax, VW, Subaru, for example), pre-drilled metric hardware are not commonly available. The only option is drill them yourself. Tom also noted, “Pre-drilled bolts cost a lot more than undrilled. It’s not unusual for the cost of a drilled AN4 or AN5 bolt to Safety wire holes can bisect the head or run to adjoining flats. be double or more. Drilling your own can save a lot of money.” He also mentioned 12-16600). This product, branded Quan- prone to deflecting with even the slight- that having the tools to drill your own tum, drills a bisecting hole through both est force. If they deflect too much they’ll bolts on an as-needed basis might get hex bolts and socket head cap screws easily snap in two (ask me how I know!). you out of a pinch someday. with shank diameters from 3/16 to 5/8 inch. You’ve probably heard the expression, If you prefer the safety wire holes across “Let the drill do the work, don’t force it.” Jigs and Guides adjoining flats (see figure 1), then you Well, that applies here in spades. Even After looking at the different drilling jigs need a different style guide. Also offered with the drill guide to help prevent the bit featured in the Aircraft Spruce catalog, I are drill guides for making holes in the from deflecting, you have to be careful. purchased a safety wire drilling jig (P/N threaded part of the bolt for either a cot- ter pin or safety wire. Watch Your Speed! A guide serves to locate the hole Machinists live by speeds and feeds. (either on center or across the flats) and to Most drill press machines and many twist prevent the drill bit from deflecting. Drill- drill sets come with a chart with recom- ing the holes can be tricky. Small bits are mended rpm settings. Basically, big drills use slow rpm and small drills use fast rpm. Really small drills use faster rpm. Here’s a simplified speed chart: Recommended Speed* Drill Size (in.) Steel Aluminum 1/16 to 3/16 3,000 3,000 ¼ to 3/8 1,000 2,500 7/16 to 5/8 600 1,500 *source: http://www.fnal.gov/pub/takefive/ pdfs/Drill_Press_Speed_Chart.pdf

Bob Hadley is the R&D manager for a California-based consumer products company. He holds Bob Hadley a Sport Pilot certificate and owns the VW-powered Victory Stanley Fun-Kist.

Photos: Lori Fahrenholtz KITPLANES May 2014 55 The Dremel tool mounts in the Work- The guide bushing on the Quantum jig When drilling a SHCS, the jig automatically Station accessory to create a micro drill doubles as a clamp to lock the bolt into centers the hole in the screw head, but press. position for drilling. A daub of cutting oil you have to watch the alignment of the helps keep the bit cool. internal hex.

The formula for estimating drill rpm considered trying to drill the safety wire ones, don’t last forever, so keep extras on is based on a recommended material holes with a hand drill. My cordless tops hand. I talked to a machinist friend about removal rate called surface feet per min- out at 1700 rpm which is too slow. A how many AN5 (5/16-24) bolt heads I ute (SFM). The formula is: spindle rpm = small drill press with a top spindle speed should be able to do before the drill gets SFM x 12/πD, where D=drill bit diameter of 2500 to 3000 rpm would be good for dull or breaks, and he suggested it would in inches. In the rpm chart we can work most of the jigs on the market, but if your be prudent to change bits after 20. Your out that 3000 rpm for a 1/16-inch drill bit jig uses a bit smaller than 1/16 inch, faster results may vary. is more or less 50 SFM (2938 rpm to be rpm is needed. exact). If we apply 50 SFM to a smaller I don’t own a small drill press, but Deburr to Finish drill size, say a #57 size drill (0.043 in.), the I have a Dremel rotary tool. I found a Once your holes are all drilled, you recommended speed is 4442 rpm. Note $49 Dremel WorkStation accessory at need to deburr the flashing from the that most drilling calculators assume you Home Depot to convert it to a micro drill openings. Even though you may not are using a standard two-flute twist drill. press. The Dremel option proved to be be able to see it, that sharp edge could Milling and lathe operations follow the a good (and inexpensive) alternative. It same SFM removal rates, but the calcu- has a very light spring with a short feed lations also consider the tooling (single lever, which combines to provide tactile point tool, multi-flute, etc.). Use Google feedback of the drilling process. I set to find SFM guides online as well as drill- the speed control to the lowest setting, ing speed calculators. All you need to do which is about 4000 rpm, and it worked is plug in the appropriate number for the fine. The Dremel bogged slightly when material you are working with and the drilling, so the actually drilling rpm was size bit you want to use, and they will kick slower. I used a technique called peck out the rpm for drilling. drilling, where you drill a little bit, retract the bit to clear the chips, and repeat until Go Small you break through. I tried drilling a bolt using my floor The Quantum jig came with two model drill press, but found the mass cobalt steel drills and guide bushings. of the quill, the heavy return spring and They obviously have taken into account the long lever arm damped out most of the possibility of breaking a bit or the bits A close-up of the exit hole reveals a nasty the feel of the bit in the material. I never wearing out. Drill bits, especially small burr.

56 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes The burr is removed by hand with a small center drill or any suitable chamfering tool. cut through your safety wire and ren- der it useless. Corrosion protection is the last step. The screw or bolt may be installed somewhere invisible to your pre-flight inspection, so it cannot be left to chance that you or someone else will remember to keep an eye on it. Either brush or spray a shot of zinc chromate primer or good epoxy paint into the hole. Make sure it permeates the full length. Wipe the excess paint from the head, let it dry and you’re good to go. J

Tools used for this project: Quantum Safety Wire Drill Jig (Aircraft Spruce #12-16600, which includes two #50/0.070 drill bits), a Dremel rotary tool, a Dremel model 220 WorkStation, and a 1/8-inch center drill for deburring.

Deburring the edge will leave a clean chamfer that will assure the “safe” in safety wiring.

KITPLANES May 2014 57 PRACTICAL ELECTRICAL Battery facts and fables for the aircraft builder–part 2. In last month’s installment we con- Their earliest efforts were exciting. Bolder sidered the role played by a battery as attempted to fabricate starved electro- a source of energy in an airplane. The lyte, sealed lead-acid cells using very engine’s starter motor poses a serious thin films of lead approximately 0.001 challenge to the ship’s battery in terms inch thick “pasted” with 0.002 inch of of load. Cranking loads up to 200 amps active material on both sides. The posi- for ten seconds represent a demand of tive and negative films were wound up 15-25,000 watt-seconds of energy. Inter- jellyroll fashion along with a very thin estingly enough, a stack of eight D-sized separator saturated with the water- alkaline flashlight batteries contains over acid mix. This “sandwich” was barely 200,000 watt-seconds of energy. While 0.010 inch thick. more than enough to start the engine, the chemistry is willing, but the construction is weak. One simply cannot load surface area of the collectors is low and D-cells to 200 amps. the gap between plates occupied by An ability to deliver large current chemistry is high. flow is not driven by the size of the Flooded lead acid and nickel-cad- cell, but by the surface area of and the mium cells were the batteries of choice space between the positive and nega- in aircraft for decades. In 1972, the Gates tive current collectors or “plates.” The Rubber Company began to develop alkaline cells cited above contain a fair a line of sealed lead acid batteries volume of chemistry which translates wherein the plates were fabricated of to an impressive capacity—but the strips of sheet lead in a jellyroll architec- ture. Gates laid the foundation for the present day Optima car and RV batter- The volume of reactive material was ies offered by Johnson Controls (http:// so small that the approximately C-sized tinyurl.com/l7h7cjy) and the Cyclon cells were only rated at 1 ampere-hour. series devices from Enersys (http:// The volume of liquid electrolyte was tinyurl.com/khlzqom). This approach to also small. But the relatively thin reactive maximizing surface area and minimiz- materials and separator, combined with ing the gap produced a quantum jump relatively large surface area, produced in battery performance. a cell with amazing load performance. About 20 years ago, a company A roll-up set of thin film plates slightly called Bolder Technologies (http:// larger than a flashlight cell would dump tinyurl.com/oybe9cd) generated a lot of over 500 amps! A 12-volt array of Bolder interest in their thin metal film (TMF) cells didn’t contain much energy. In fact, technology (http://tinyurl.com/np7jdzb). it was less than a 12-volt array of D-size

Bob Nuckolls retired from Beech Aircraft in 2007 after more than 45 years of work in certificated aviation and over 25 years of support for the homebuilt aircraft industry. Bob publishes “The Aero- Electric Connection” from his web site at http://aeroelectric.com. Robert L. Nuckolls, III He also hosts the AeroElectric-List on Matronics.com. This special-interest forum serves approximately 1600 participants.

58 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes capacity, I think), the battery must be removed and replaced. But as far as the airline is concerned, it’s a “failed” battery requiring R and R with attendant risks to schedules. Line personnel leaving stuff turned on in parked airplanes is proving an expensive activity! Reducing battery weight is a powerful siren call for folks who fly airplanes alkaline cells. The difference was that three times the voltage for a six-times for a living. Pounds added to empty the Bolder cell would deliver everything improvement in total energy over the weight reduce revenues. Development it had at a rate sufficient to crank an alkaline chemistry. efforts in Li-Ion are moving ahead right engine—perhaps only one time—but it This technology comes with its own smartly in the Wichita aviation com- would do it. unique risks. We’ve heard of the avia- munity (http://tinyurl.com/kfnblyh) and There were several exciting product tion mishaps involving Li-Ion batteries. elsewhere. They will become the gold start-ups based on these cells. The cells What’s more, stories in the news tend standard for lightness and energy den- lacked robustness and proved difficult not to offer the whole picture. For exam- sity in aircraft batteries. to manufacture, so the company sold ple, had the B787 never experienced the I’ve cited these examples of battery out a number of years ago. The TMF cells battery fire, Boeing would still be experi- style and performance to emphasize re-surfaced a few years later offered by encing heartburn over the incorporation the fact that battery size is not a reli- GP Batteries (http://tinyurl.com/l8ptkqj) of this technology. Recharging these able predictor of capability to deliver in this automotive jump-starter (http:// batteries after deep discharge must be heavy loads (engine cranking) or power tinyurl.com/mu8oe6c). They rate their done in a facility dedicated to that task. up the panel after the alternator quits diminutive TMF cells at only 0.9 ampere- It seems that if a battery is discharged (capacity). Further, one should be cau- hours, yet they are purported to crank below a certain level (about 30% of tious when pondering the marketing a vehicle with a dead battery (This hype that inevitably accompanies a new information was found in the Internet technology’s introduction to the mar- archives—I’ve not found current offers ketplace. Not a month goes by that I do to sell this product). It seems that GP not read of some new “breakthrough” Batteries may have encountered the in the lab that promises to change the same magnitude of difficulties as Bolder rules of the battery game. Bolder Tech- Technologies. In fact, their web site list- nologies (and perhaps BG Batteries) ing of products presently speaks only of once thought so. lithium-ion cells Practical instances of an electrically Lithium ion technologies are the cur- dependent engine were exceedingly rent champions in the race to store the rare 25 years ago. But we still worried most energy in the smallest and light- about keeping things on the panel lit est package while maintaining the abil- up. Alternators and flooded lead-acid ity to crank engines. These Li-Ion cells batteries did not enjoy stellar reputa- are slightly larger than an AA-cell, but tions. About 1990 at Oshkosh, I recall a offer twice the ampere-hour rating at couple of vendors offering Eagle-Pitcher

Photos: Robert L. Nuckolls, III KITPLANES May 2014 59 sealed-lead acid batteries, along with electrical endurance equal to or the necessary cable for plugging the greater than fuel aboard was a battery into ship’s cigar lighter. No STC good thing to do. It was not or other approval was needed for “loose difficult to design a sys- equipment.” However, the idea of shar- tem that allowed one ing cabin space with a 12-pound chunk to comfortably expend of lead and plastic during a rollover was all the fuel aboard with not pleasant to contemplate. battery power left over. Nonetheless, a number of these things A dedicated “endurance were sold based on worry factors, jacked- bus” was tasked with oper- up by what I call “dark-n-stormy-night” ating only those equipment stories in the journals. Many examples items needed for comfort- can be found by looking in almost any able navigation to the airport aviation magazine’s archives. of intended destination. It was Loss of an engine driven energy loaded to perhaps three amps; a bat- source shifts electrical support of sys- tery capable of carrying that load for tems for sustained flight to one or more the time it took to empty the fuel tanks batteries. In the technically simpler was relatively small. Successful alterna- single failure (like an alternator) from days of vacuum driven instruments and tor-out operations with an electrically becoming an emergency. solid-state rudimentary radios, design- dependent engine start with knowing The artful crafting of a successful, low- ing for an alternator-out endurance the energy required to (1) stay aloft and risk airplane is a study in tradeoffs— load was pretty simple. Fuel aboard (2) navigate. tradeoffs that compare complexity and is a hard limit for endurance readily Once the numbers are known, the weight with cost of ownership. Backup acknowledged by every pilot and usu- builder can begin to size the number of systems add both weight and cost to ally treated with respect. I suggested to batteries and partition their duties. The the completed airplane. I’ve written my readers back then that striving for point of the exercise is to prevent any often that the lowest risk systems are not necessarily those that suffer the fewest failures. The system suffering moderate, but economically managed, failures may still be quite reliable from Print and Digital the perspective of risk. I suggest further that an airplane with lots of hardware bells and whistles may be a higher risk vehicle when things are not going well in the cockpit. Next month, we’ll consider value: return on investment for chasing the holy grail of weight savings and/or wrapping ourselves in the golden security blanket of multiple backup systems. We’ll do a market study on the current offerings of lithium-ion batteries for vehicles and give you some tools to evaluate suit- ability of these products to your project. The low-risk, electrically dependent airplane needs power. I will suggest again that the battery can and should be the most reliable source of energy in your airplane—and with a little understanding of supporting simple ideas, it’s not a difficult goal to achieve. We may not have a practical way to achieve elec- Either Format – Great Savings! trical endurance that exceeds fuel endur- Subscribe Now at www.kitplanes.com/subscribe ance, but we can surely do better than the holy-watered “30-minute rule.” J

60 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes The Dawn Patrol Fun with the Hun in the sun. I was out on an early morning patrol Spandau machine guns, would be lurk- constant turning of my head to see if in my faithful little Nieuport 11, Le Fau- ing along the way, just waiting for some- anyone was lurking back at my “six,” con Gris (The Gray Falcon). The high one like me to try and make a run on the getting ready to shoot me down. command had ordered us to make an Drachen emplacement. All in all, things weren’t too bad. I’d unusually early dawn patrol to try and My mighty Le Rhone 80-horsepower had a good breakfast with wine, and surprise the German observation bal- rotary engine was singing its normal the metal flask in my flying jacket was loons called Drachens. We were going throaty growl. It was also spewing out full of medicinal blackberry brandy. to try to catch them as they were being a fine mist of atomized castor oil. This Brandy is the WW-I pilot’s antidote readied for their usual morning spying. rotary engine byproduct mist was coat- for the consequences of breathing They wanted to observe what over- ing me and the plane with a glistening, in the mist of concentrated castor oil night changes had been made to the odoriferous shine. I had to keep wiping spewing out of the whirling two-cycle complex of trenches along the front, my goggles off with the white (well... rotary engine. Yep, it’s a fact of life that close to our field in Luxeuil. Drachens it was white before I took off) silk scarf concentrated doses of castor oil make are filled with hydrogen, so shooting wrapped around my neck. The main for an excellent laxative. A few hours them down is usually a very satisfac- reason the scarf was there was to keep breathing in a fine mist of burned and tory experience as they explode and my neck from getting chaffed by the unburned castor oil results in some burst into flames. Of course, there is a downside…Drachens are always sur- rounded by several concentric layers of antiaircraft guns. So getting close enough to shoot them down is not an easy endeavor. But I, the Junkyard Dog, am not the kind of guy to back away from a challenge. Nosirrebob…Any Drachen I found that day was going to be meat on the table. They had no idea who was coming to ruin their day. I was armed and dangerous and head- ing in harm’s way. My 30-caliber Lewis machine gun mounted on the top wing was loaded with incendiary bullets. All it would take would be one lucky shot, and that balloon would toast. (In more ways than one, too!) Flaming death rode the air over the trenches! The only other concern I had was there was always the possibility that one of the deadly German Fokker E-III The fuselage gets its first close inspection looking for places to fix, replace and/or get Eindeckers with their synchronized twin ideas. Mark, Sharon and Dick make plans.

has written two books about the joy of flying; “You Want To Build And Fly A What?” and “Fokkers At Six O’clock!!” He was the recipient of Flying’s 2001 Bax Seat Award “for perpetu- ating the Gordon Baxter tradition of communicating the excitement and romance of flight.” Dick Starks Dick and his wife, Sharon, both fly WW-I replica aircraft.

Photos: Dick Starks KITPLANES May 2014 61 Dick Lemons, Dick Starks, Dave Laur, and Mark Pierce make plans Sharon, Dick, and Dave clean the stabilator with Scotch-Brite pads. on how to clean the tubes on the stabilator. pretty alarming cases of the “scream- I circled around and got into position for It was the polished cowl and spinning ing go-squats.” Blackberry brandy is my attack. prop of the feared Fokker E-III. Twin the only actual medicinal stop-leak It was time to open a big drum of Spandaus were already flashing fire as answer that really works and is easily industrial-sized Whup-Ass! I pulled the death-dealing lead stitched jagged available to pilots. It makes for good back on the stick for some altitude to holes in the fabric on my right wing. personal antifreeze, too. get out of small arms effective range I was toast. As I crossed over the German lines, for my final attack. Reaching the height Well, rats! Foiled again by the cursed I started my search for the elusive I wanted, I pushed the stick forward Lone Eagle of Verdun, Baron Von Dick- Drachens. They should have been easy and started my dive onto the target. ielee Lemons, terror of the Western Front. to see, silhouetted against the rising The observer in the Drachen’s basket Time quickly reset itself to the pres- sun. But they were snuggled up tight had already bailed out and was drift- ent. Dick Lemons had sneaked into the against the ground, hidden in the thick ing to earth under his parachute. Smart airport and taken off after I’d started my morning fog. guy! I bored in to the target. Just as I sortie of the fields to the south of Lib- Then I saw it on the horizon about got ready to squeeze the trigger on the erty Landing International Airport. two miles away. It was just starting its Lewis, a shadow fell over me. Dick was in his brand-new Airdrome ascent out of the dense fog covering the Stunned, I looked up in my rear-view Aeroplanes Fokker E-III. Dick pulled up shell-cratered ground. mirror mounted in front of me on the beside me and grinned across at me. He I started my stealthy stalk. I wanted to rear cabanes. What I saw froze the blood was so proud. He’d sneaked up behind and be shooting with the sun behind me, so in my veins. below me in my six o’clock low position

Mark Pierce pulls some large-flange fabric rivets on the wing. Just because you’re building ultralight doesn’t mean you have to cut any corners for safe flying. We used the same rib spacings that are called Mark Pierce and Dave Laur work on the wingtip of a covered wing. for in AC 43.13-1B, the FAA’s aircraft inspection and repair manual.

62 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes While the wings were being worked on in the workshop, the fuse- The fuselage half covered with 1.6-ounce Dacron. The Stewart lage was being worked on in the living room. Doesn’t everyone Systems EkoBond cement is the cat’s meow for covering in situ- have a Fokker in their living room? ations where you don’t want to work with volatile components. You can use it next to an open flame with no problem. where I couldn’t see him. Then he’d Airdrome Aeroplanes Morane-Saulnier Now, dejected, forgotten, and lonely, popped up behind me and got in position “L” Parasol replica and had really liked it was mixed in with a plethora of com- so his shadow fell right over my cockpit. the way it handled, and the way the Val- pleted planes, pieces of planes, wings, Pretty sneaky, I thought. I liked it! I’d ley Engineering Big Bad Twin 4-stroke motorcycles, tail feathers, wheels, engines, have to try that on him next time we engine had hauled it around. hot-rods, and strange unknown projects went up against each other. On one of our periodic trips over to under way. The fabric was so rotten, a I took one last look at the Drachen Bullwhip Baslee’s House of Pain (aka Rob- hard look would poke a hole in it. receding in the distance behind me as ert Baslee’s Airdrome Aeroplanes plant, Dick and I headed back to Liberty Land- located in Holden, Missouri), we’d stum- ing to talk over the flight. The Drachen bled over Robert’s 1996 prototype Fok- was actually a big tall cottonwood tree ker E-III. It was now sitting alone, tattered in the middle of a field, but it sure did and forlorn in the back of his hangar. I’d stand out in the early morning fog, just seen it fly when he showed up with it like a real balloon would have. at the 1996 Gathering Of Eagles at the Gardner, Kansas Municipal Airport. It had How It Came About shown outstanding performance, and it Back in 2007, Dick had flown Sharon’s was a legal ultralight (with added chute).

The large-flange aluminum rib rivets are riveted in place through rib reinforcing tape.

KITPLANES May 2014 63 The Fokker Scourge In the spring of 1916, the Fokker E-III was the reason that period of time was called “the Fokker Scourge.” With its synchronized Spandaus firing through the prop, it was a killing machine. All allied planes became basically just victims. The introduction of the nimble little “baby” Nieuport 11 leveled the playing field right away. In fact, the balance of power shifted so much in the Nieuport’s favor, the Germans copied it. The copy was the Siemens-Schuckert D.1. That was followed by the Albatros D.1, which was more of a match for the Nieuport 11. For the rest of the war, about every four Finished tail feathers ready to go. The small crosses are vinyl from an automotive sign shop. or five months, both sides would bring out a new design that would shift the favor to tubes from water freezing in them, there You know, when the weather is too bad their side…for a short time. was not a lot of work needed before this to fly or even sit in the hangar and sling In May of 1918 the Fokker D.VII, arguably bird was going to fly again. Certainly it the bull, working on a plane with three or the best fighter to fly in the war, was intro- was going to be easier than building the four other airport bums is just about the duced to combat. The D.VII was so effective plane from scratch (or so we thought!). best quality time you can have. Over the that it was still in production in 1929. The It just needed a really good cleanup, a passing of many winter nights, we’d all treaty of Versailles stipulated that NO D.VIIs good, hard look-over, and a lot of tender gathered over at Dick’s house with cases were to be destroyed. They were turned loving care to get it back in the air. of beer (hard cider for Sharon, who, hea- over to the different air forces on the allied We went back home, loaded up the then that she is, hates beer) and bowls side for study and research. Stealth Van with tools, and hooked up of popcorn. Armed with Scotch-Brite —D.S. our utility trailer. Then, back to the House scrubbing pads, MEK, and other cleaning of Pain we went to pick up the bird. agents, we cleaned that plane’s frame- It was hauled over to Dick’s house work until it looked like it was brand new. Resurrection for the badly needed extensive clean, Split tubes were replaced. Crisscross drag After a little negotiation and threats, exam, and rebuild. This was going to be wires were replaced on the wings, and the plane was Dick’s. We took it apart, a perfect wintertime project—just what several new ribs on the ailerons, stabila- ripped some fabric off, and checked it the doctor ordered to help The Dawn tor, and rudder were fabricated. Finally, it over. With the exception of several split Patrol get through the winter months. was ready to cover.

64 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Dick’s MG-TD (his other toy) and the Eindecker pose in front of a plane-eating stand of soybeans. We know all about soybeans and planes.

The Fabric of Life coat either. This also saved more weight. Mark Pierce and Dick Lemons are our Dick did all the big Iron Crosses and real covering gurus. Tom Glaeser, Dave other trim with the roller, too. Laur, Sharon, and I just do what we’re It came out beautiful and was very light! told to do. The Valley Engineering Big Bad Twin With six different people doing dif- engine with its Series 3 PSRU lets the ferent things at the same time, we had engine swing a really big 80x46-inch that plane covered in record time. By slow-turning prop. This is a lot different using Stewart Systems EkoBond Cement from my direct-drive VW “buzz saw” on (which we all love), we didn’t blow up the front of my Nieuport. The 48-hp Big the house or start speaking in tongues Bad Twin pulls just as much as my 80-hp as work progressed. VW. The big prop makes the difference. Dick painted the whole plane using The finished bird will take your fine-finish rollers with Glidden premium breath away. semi-gloss exterior latex house paint, on sale for $20 a gallon. With the UV pro- Fit for Flight tection built in, he didn’t need an under- It flies as good as it looks, too. Dick likes coat of UV protection. That saved a lot of to fly the E-III a lot more than his Air- weight. Also, the paint used right out of drome Aeroplanes Fokker Triplane. Or the can is thick enough that it seals the in his words, “This E-III is the perfect little fabric. This meant we didn’t need a filler plane for a wannabe WW-I warbird pilot.”

The KISS instrument panel (Keep It Simple Dick got a hussar’s helmet off eBay Stupid). Everything you need for safe VFR and tried flying with it once. That was flight. enough— it hurt his head.

KITPLANES May 2014 65 Airdrome Aeroplanes www.airdromeaeroplanes.com Culver Props and Valley Engineering www.culverprops.com/index.php Experimental Aircraft Association http://eaa.org Graham Lee Nieuport Replicas http://nieuports.com Great War Association www.greatwarassociation.com Replica Fighters Association www.replicafighters.com/Home Taxiing in from the first flight. Salute to Veterans’ Airshow www.salute.org All the controls are very light, and the When spring arrived, Dick’s E-III was Stewart Systems EkoBond incredible roll rate will tumble your per- ready to rock and roll. It flew great Cement sonal gyros. It’s an-easy-to-handle-on- right out of the box. Dick and I have www.stewartsystems.aero the-ground taildragger, too. My Nieuport had many happy flights together since The Kansas City Dawn Patrol will roll from 45 degrees to 45 degrees then—plus some pretty exciting com- www.kcdawnpatrol.org/index.php in about four seconds. Dick’s Airdromes bats. Since his E-III is 15 mph faster than Aeroplanes Fokker E-III will do it in less my Nieuport, 150 pounds lighter, has a It’s kinda funny…two of the deadliest than a second. It will really snap your roll rate three times faster, and climbs enemies from that war are now fly- neck! As a matter of fact, so will Sharon’s like a scared monkey going up a vine, ing together for fun. Kinda nostalgic if Morane Parasol. They both have the exact I’m just pretty much a target for him you’re a maudlin sort. same wing with full-span ailerons. to toy with. I can never get on his tail. Yep, the adventure continues. 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, or other similar names. addresses for these firms include Dallas, tX; lincoln, ne; Omaha, ne; san luis Obispo, ca; salt lake city, ut 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, ebsco 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 800 connecticut ave norwalk ct 06854 should you have any questions at all about mail that you receive, please contact us at our web site: www.kitplanes.com/cs or call us toll free to speak to customer service.

66 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes BACK ISSUES List of Advertisers O NEW eBOOK O Please tell them you saw their ad in KITPLANES® Magazine. eBook download is the exact same KITPLANES® interactive makes it quick and easy for you to receive instant magazine as on the newsstand. information about products or services directly from our advertisers’ web sites. The difference is: ➥ Go to: www.kitplanes.com/links for a virtual shopping tour via links to their web sites. you get it now! ➥ Call the phone numbers listed below and be sure to tell them you saw their ad & in KITPLANES® Magazine. no shipping costs for e-books! Advertiser page # telephone Advertiser page # telephone Advanced Flight Systems, Inc. 23 503-263-0037 Belite Aircraft 70 316-253-6746 (a big savings for our international customers) Aircraft Spruce & Specialty CV4 877-4SPRUCE Better Half VW 71 281-383-0113 eBooks download as a single, full size, full color .pdf document which you can view Aircraft Tool Supply Co. 53 800-248-0638 Carlson Aircraft 70 330-426-3934 on your desktop, laptop or tablet computer. Avemco Insurance Company 35 888-241-7890 Falconar Avia Inc 69 780-465-2024

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72 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes Operating limitations, selling a homebuilt, aircraft that can’t be registered. By Mel AsbeRry Question: I read your Septem- certificated aircraft, our operating limi- inspection required by the operating ber 2013 column with the ques- tations include a paragraph that makes limitations unless he possesses an FAA tion about TSO’d position lights. 91.205 apply to our aircraft during night mechanic certificate with an airframe You mention “our operating limi- and/or instrument flight rules. and powerplant rating. On the other tations.” What are operating limi- Question: I am currently building hand, you, the original builder, may per- tations? Is this something that is a four-place Bearhawk Experimen- form that inspection, provided you have specified in the paperwork for our tal. If I sell it someday, will the sale the repairman certificate for the aircraft. aircraft? Who writes them? affect the category of the airplane Question: About 15 years ago, my The issue of TSO requirement for and the regulations the new owner flying buddy bought a Quad Cit- position lights for night operation will need to comply with? Is there ies Challenger that was fully com- of an E/A-B aircraft caught me by anything I should do during the pleted by the dealer. He never did surprise—I would have thought it build to ensure that the buyer will get it registered, but now he wants was OK to use non-TSO’d lights. have a smooth transition regulation to. What does he need to do? Answer: Operating limitations are wise, as far as the sale and flying of Answer: Unfortunately your friend issued by the inspector in conjunction the airplane is concerned? is somewhat out of luck. There are only with the airworthiness certificate. Answer: Once you complete your two categories eligible for this type of air- They are actually part of the airwor- aircraft and have it certificated, it will craft: Experimental/Amateur-Built and thiness certificate. In other words, the become an Amateur-Built aircraft in Experimental Exhibition. Since the air- airworthiness certificate is not valid the Experimental category. That will craft is factory built, it does not qualify unless it is accompanied by the oper- never change. as Amateur-Built. ating limitations. As far as complying with regulations, There is a possibility of getting it certif- Basic operating limitations are spelled the aircraft must always be operated in icated under Exhibition, but it does not out in FAA Order 8130.6. While an accordance with the operating limita- really meet the intent of that category, inspector cannot remove any require- tions that are issued to the aircraft. A sale and it is very restrictive. If your friend is ments, they may add something they or change of ownership does not affect interested in going this way, he should deem necessary for safety. For example, the operation of the aircraft. call the local FSDO or MIDO, but don’t an inspector can add hours to Phase I The new owner, or anyone else for that be surprised if they refuse it. J testing, or issue only Phase I and require matter, may maintain and/or modify another inspection before Phase II, etc. the aircraft. The only restriction toward Please send your questions for DAR Since 91.205, the FAR that lists maintenance is that the new owner Asberry to [email protected] with requirements for aircraft, only applies to may not perform the annual condition “Ask the DAR” in the subject line.

Photo: Mel Asberry KITPLANES May 2014 73 Aeroelasticity II– aileron flutter. In our discussion of aeroelasticity in airframe structure unacceptable, even if mass and inertia. In some modes, where the last issue, we have seen airplanes it does not cause immediate damage. the aerodynamic force that arises from are not perfectly rigid and their struc- In more severe cases, the flutter oscil- deflection acts like a centering spring ture does distort in flight due to aero- lation does not reach a limiting steady- (aileron deflection for example), the fre- dynamic and inertial forces. Structures state amplitude, but grows rapidly once quency is also a function of airspeed. do not just deflect. They can also vibrate the oscillation begins. This situation is For flutter to occur, two conditions or oscillate. Most of these vibrations are extremely dangerous because if the must be met. First, two modes must damped, and relatively benign. In certain building flutter is not stopped quickly, it have the same natural frequency. When cases, however, aerodynamic and inertial will cause catastrophic structural failure the natural frequency of two modes forces couple to produce powerful and of the airframe. is the same, the motions of the modes destructive oscillations called flutter. couple, allowing one mode to directly Flutter is an oscillation that is driven The Flutter Mechanism affect the other. by the interaction between aerodynamic A structure has multiple degrees of free- The second condition for flutter is that forces and the elastic characteristics of dom, or ways it can distort. Each type of deflection in one mode causes forces the structure. Sometimes, flutter appears distortion gives rise to a mode of vibration. that drive a deflection in the second as a sustained limit cycle oscillation that For example, on a cantilever wing, the first mode. For example, wing twist changes does not damp out, but maintains steady two structural modes are wing bending, the lift of the outer portion of the wing, amplitude. Such a flutter is often referred where the wing bends up or down like a which in turn changes the bending to as “buzz” and is very undesirable diving board, and wing torsion, where the moment on the wing. Accordingly, a because of the cyclic loads it puts on the wingtip twists relative to the root. Each change in wing twist (one mode) causes airframe, which can cause failures due to structural mode has a natural frequency a change in wing bending (other mode). fatigue or working fasteners. Most cer- at which it vibrates when it is excited by a If the natural frequencies of the first tification authorities consider sustained force. The natural frequency is determined wing bending mode and the first wing aerodynamically-driven oscillation in the by the stiffness of the structure and its torsional mode are the same, there is a potential for flutter. Other factors affecting the onset of flutter are the amount of damping in the system and the magnitude of the driving aerodynamic forces. Damping absorbs energy, while opposing the motion of the structure. An example of this is friction in a control surface hinge or linkage. When the surface moves, the friction opposes the motion and absorbs some of the energy trying to make the surface move. The faster the surface moves, the more energy the friction dissipates. Because it tends to This aileron uses a weight on the end of an arm that protrudes well ahead of the hinge reduce the motion of the structure, line to achieve a nose-heavy aileron. damping delays flutter onset.

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

74 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes The aerodynamic forces that drive the deflections increase as a function of the dynamic pressure, which is proportional to airspeed squared. The higher the airspeed, the higher the aerodynamic force, and the more energy the aerodynamic forces can provide to drive the structural oscillation.

Aileron Flutter One of the more troublesome types of flutter encountered in general aviation airplanes is aileron flutter. Aileron flutter first appeared when designers learned how to This aileron design uses a length of iron water pipe in the nose to provide balance make early airplanes, usually monoplanes, about the hinge point. faster then the original open box kite style motion. This deceleration will cause the the vertical accelerations of the aileron machines. Many racers of the 1920s and aileron to flap upwards, producing aero- caused by wing bending do not result in 1930s (including the GeeBee Z and the dynamic down force that drives the wing an aileron deflection. This is the function Supermarine S4) succumbed to aileron back down at the same time as the wing’s of mass balances. By attaching a mass flutter, which was a mysterious and little natural spring action is also accelerating that is forward of the hinge line to the understood phenomenon at the time. the tip down. Again, the aileron lags, aileron, we can move the center of grav- If an aileron is deflected and then producing force that drives the wingtip ity of the aileron to the hinge line. If the released, aerodynamic moment will drive down until the wing’s stiffness slows the aileron CG is at the hinge line, the aileron it back towards the trail position. Because motion and starts the tip accelerating will not deflect as a result of vertical accel- the aileron has some inertia, it will over- back up. The aileron lags downwards, eration. If the aileron does not deflect, it shoot and then be driven the other way, and the cycle repeats. If the natural fre- does not produce lift forces in phase with back towards trail. Usually, this motion is quencies of the wing and aileron are sig- the bending. This in-phase force from the highly damped, and the aileron will stop nificantly different, the aileron will return aileron is what drives the flutter. If it is moving quite quickly. The oscillation, even to trail quickly after the initial bump, and eliminated, so is the potential for flutter. if it is damped, has a natural frequency the system will be stable. It is important to note here that for and amplitude that change with airspeed. If the frequencies are the same, then mass balancing to be effective, the CG of The other structural mode that plays the aileron motion will couple with the the control surface must be at or ahead a part is the first wing bending mode. In wing motion so that the aileron proof the hinge line. Partial mass balancing this mode the wings bend up or down duces oscillating forces that are in phase that moves the control surface CG for- symmetrically. If the wing is excited by a with the wing bending and amplify the ward, but not all the way to the hinge gust, or a change in lift due to a maneu- motion. The vibration will grow quickly line, can be ineffective, and in some cases ver, the wing will vibrate up and down until the damping in the system limits its actually cause flutter by changing the like a diving board. amplitude to a steady-state buzz, or until natural frequency of the aileron without At an airspeed where the natural fre- the forces get so large that they destroy eliminating the “lagging” deflection due quency of the aileron’s motion around the structure. This destructive diver- to vertical accelerations. the hinge is the same as that of the first gence can happen very quickly, with only Aileron balancing comes in several wing bending mode, there is the poten- a few seconds between the beginning of forms—with weights on arms and heavy tial for flutter. the flutter and catastrophic failure. leading edges being the most common. The other key player in aileron flutter is the mass properties of the aileron. An An Ounce of Prevention Control System Stiffness: upward motion of the wingtip will accel- To prevent aileron flutter from happen- A second approach to preventing aile- erate the aileron upwards along with the ing, we need to make sure that the cou- ron flutter is to design the control system wing. If the center of gravity of the aile- pling between the wing bending mode to constrain the aileron rigidly so it cannot ron is behind the hinge line, the aileron and the aileron oscillation mode does make uncommanded deflections relative will lag and deflect down. This deflec- not happen. There are at least a couple to the wing. If successful, this approach tion produces more lift at the tip, which of ways to do this. essentially makes the aileron a rigidly-con- further accelerates the wing upwards. nected part of the wing. This effectively The aileron continues to lag and drive Mass Balancing: eliminates the “aileron flapping” mode the wing upwards until the stiffness of One way to prevent flutter is to alter the that generates the acceleration-induced the wing slows and stops the upwards mass properties of the aileron so that aileron deflections that drive the flutter.

Photos: Barnaby Wainfain, Paul Dye KITPLANES May 2014 75 Large or fast aircraft frequently use non-reversible hydraulic control actuators like this to provide control system stiffness and prevent aileron flutter.

This approach is widely used on high- flight critical structural components of the performance airplanes with powered airplane. It is common practice to require control systems. The aileron is controlled that a manually-controlled airplane be by several hydraulic or electric actuators able to survive disconnect or failure of that are strong enough to act as a rigid a single control and remain sufficiently link between the aileron and the rest of controllable for the pilot to land safely. If a the wing. The design of these systems is control disconnect leads to aileron flutter, not easy since it is critical that the link- this requirement is obviously not met. ages be very tight, with no free play that A manual control system also depends allows the aileron to move indepen- on the pilot holding the stick to constrain dently of the actuator. Relatively small the control surfaces. If the stiffness of the amounts of free play in the actuator, con- control system is being used to prevent trol linkage, or any of the connections in flutter, the airplane will have different the system can allow the aileron to move flutter characteristics in the stick-free enough to reintroduce aileron flapping mode if the pilot lets go of the stick. into the flutter equation. Obviously, depending on the pilot to A few attempts have been made to use hold the stick rigidly at all times to ensure cable control systems to constrain un- the structural integrity of the airplane is mass-balanced ailerons enough to pre- not a good idea. vent flutter. Depending on the control For airplanes with manually controlled cables of a manual system to constrain ailerons, mass balancing is the preferred, the aileron enough to prevent flutter and much safer, way of preventing aile- is very risky. The tension in the control ron flutter. cables must be high to keep things safe, and the system is not tolerant of any Aileron Flutter is Serious stretching or mis-rigging of the aileron Business! control cables. The cables can stretch One final caveat: More than one fatal over time and loosen, or change length homebuilt accident has been caused a little bit due to changes in temperature. by builders omitting or modifying mass If this happens, the airplane can become balances. This is an extremely danger- flutter-prone with little or no warning as ous thing to do. Any change to the mass the result of a subtle change that is dif- balances on an existing design invali- ficult or impossible to detect during pre- dates the flutter-cleared flight envelope flight inspections. of the airplane and can lead to flutter at Depending on control cables to pre- well below the published never-exceed vent flutter makes the cables safety-of- speed of the original design. J

76 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes The ultimate ground plane. This is by far the best ground plane air- England, and in December of ‘01 trans- going to be radiation slightly above and craft band antenna I’ve ever seen. Perhaps mitted • • • (the Morse code letter S) from slightly below this angle. the best ground plane antenna ever built. Newfoundland to England. That may Brother Marconi used waves way down And this is for builders of corrosion not sound like such a big deal until you in the 2-4 MHz range. We need to do queens, termite traps, and Tupperware understand that those Morse code dots something in the 118-137 MHz range. airplanes, with hope that you can all are what we now call “bits,” and we send Enter the concept of frequency. Down work together to make these anten- tens of billions of digital bits daily around at Marconi’s frequency, antennas were nas for your hangars. All you’ll need for the world on many of the same principles hundreds of feet long. In our aircraft construction materials are aluminum that Marconi used in 1901. band, we are talking inches or centime- sheet, copper tape, pine dowels, and Another bit of trivia for your collection: ters. And, what Marconi did not know PVC plastic. When Lindbergh left Marconi’s transmit- was that his waves would travel by “skip” What is and why have a ground plane? ter location in Newfoundland, the first off of the ionosphere thousands of miles, Let’s go back to a cold winter day in landfall he made in Europe was within while our aircraft band signals are abso- Newfoundland: December 12, 1901— spitting distance of Marconi’s receiving lutely line of sight. nearly two years to the day before those station in Cornwall. So, given that our frequencies are brothers at Kitty Hawk decided that we So, on to the antenna. Marconi judged way above Marconi’s vertical (literally could fly. And at exactly this same spot in (correctly) that Hertzian waves (or what “ground” plane) antennas, and since fre- Newfoundland, Lindberg left the North we now call radio waves) would launch quency and wavelength are reciprocals American continent 26 years later on his off a vertical antenna rod that was per- of one another, we have the option of way to Paris. pendicular to the surface of the earth building our smaller “ground planes” out But I digress. Feller by the name of Mar- (sort of like a fence stake) at an angle of metal rather than earth. coni got the wild idea that radio waves roughly equal to half the angle between I don’t think it is a great leap of engi- (called Hertzian waves in those days) the rod and the earth’s surface. This will neering faith to think of a VHF ground could travel across the horizon. He set launch Marconi’s signals at about a 45° plane built out of aluminum. But now, up a transmitting station in Newfound- angle. He was absolutely correct, but let’s couple the interesting and serendip- land, a receiving station near Cornwall in didn’t quite understand that there was itous ways of making the antenna.

The PVC mounting piece with the BNC connector and copper braid ready for soldering on the radiating elements.

is the chief avioniker at RST Engineering. He answers avionics questions in the Maintenance Bay forum at www.pilotsofamerica.com. His wife, Cyndi Weir, was his high school sweetheart 50 years ago and now she keeps Jim from making stupid blunders in spelling and grammar. Jim Weir Check out www.rst-engr.com/kitplanes for previous articles and supplements.

Photos: Jim Weir KITPLANES May 2014 77 The hole in the end of the square dowel that will mate with the center conductor on the BNC connector. This “connection” is purely for mechanical stability. It has no The ground plane part of the antenna on a plastic mounting mast. electrical function.

If we have a true antenna (quarter are absolutely not electrically required. UG-1094 BNC fitting into that hole, con- wave, explanation later) over the earth, They are there to keep the ground plane nector side down. Locate a source of the natural feed impedance is 32 ohms. elements from swinging in the wind. half-inch wide sticky-back copper tape. However, if we build a dipole (several Woodbutchers, your turn. I need a Locate a three-inch piece of copper braid columns back in Kitplanes®), the feed half-inch square dowel that most hard- (desoldering braid or braid stripped from impedance is 72 ohms. Somewhere ware stores have. Work with the num- a short piece of coax cable). between the true vertical antenna (90° bers below to find out how long; the little Here’s the details of construction: to ground) and the dipole (0°) is the milled “dowel” at the top has no electrical • Write down the frequencies you magic 50Ω number that we want for function—it is there to keep the antenna want to cover. Take the lower fre- communications antennas. rod from vibrating. quency, add to it the upper fre- Strangely enough, that is at a 45° Plastic Pushers—you are responsible quency, and divide by two. For the angle between the “radiating rod” for supplying the mounting fitting (a aircraft band, this is ((118+137)÷2) = and the “ground plane.” And, we have three-quarter inch PVC flat-bottom 127.5 MHz. Divide 2953 by this fre- achieved the goal of not radiating our end cap) for the BNC connector and quency to get the measurement for a power above the horizon, but nearly the final three-quarter inch of PVC pipe center-frequency quarter-wave in air. directly at the horizon, which will give that covers it all. Get a rubber grommet 2953÷127.5 = 23.2 inches. us maximum range to distant aircraft. or washer that force-fits into the pipe • the start is a metal mounting plate. Another Weir two-fer. with a hole in the center to fit over the Dimensions are not critical, so long as OK, tinbenders, front and center. There machined dowel. the legs and the PVC mounting fitting is a small aluminum plate that contains a Electronickers, here you go: Get the don’t interfere with one another. For mount for the PVC coupling and attach Tupperware and tinbenders to drill a the aircraft band, a plate three inches holes for the ground plane elements. The three-eighth inch hole in the dead center by three inches is a good place to start. braces you see about two-thirds of the of the aluminum plate and the dead cen- From the square plate, cut the corners way down the ground plane elements ter of the PVC mounting fitting. Mount a to make an equal-sided octagon. I used

The copper radiating element soldered to the copper braid. The end of the wooden dowel milled down to fit the grommet.

78 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes 50-mil (0.050”) aluminum because it between band center (127.5) and the braid. Push the braid onto the center is what I had. Thickness is non-critical. low end of the band ((118+127.5)÷2) = pin of the BNC connector on the inside However, for physical robustness, I 122.75 MHz, and the high end of the of the PVC fitting, as far down as it will wouldn’t use much thinner than 30 mil. band ((137+127.5)÷2) = 132.25 MHz. go. Solder the braid to the pin. Use • Drill a three-eighth inch diameter The copper tape lengths of these two some silicone sealant between the hole in the center of the plate and a frequencies come from dividing 2547 braid and the metal of the connector matching hole in the center of the PVC by these frequencies. This gives us two so that there is no chance of the braid mounting fitting. Use the BNC connec- pieces of tape, one 20.7 inches long and shorting to the ground metal of the tor to mate the plate to the fitting. Fas- another one 19.3 inches long. These are connector. Fit the dowel over the BNC ten securely with the lock washer on the “radiating elements.” center pin and form the braid up and the inside of the PVC fitting. • take the longer of these two pieces of over the copper-taped dowel. Remove • Manufacture four ground plane legs. tape. Cut a half-inch square wooden the dowel and solder-tin the braid. The width is fairly non-critical, but dowel one-quarter inch longer than • press the dowel down as far as it will past about 4% of a quarter-wave, the longest piece of tape. Drill a one- go onto the center pin of the BNC you reach diminishing returns. Four eighth inch hole a quarter-inch deep connector and solder the braid to percent of 23.2 inches is 0.92 inch, so into one end of the dowel. Use a sander the copper radiating elements. Be I used one-inch stock. Make them so or a grinder to mill the other end of the careful not to let the dowel put stress that the distance from the center hole dowel into a circle about a quarter-inch on the braid, put the PVC pipe over in the mounting plate to where the in diameter. the dowel and pipe-glue it into place. end of the ground plane legs end is • Carefully affix the long piece of tape Press the grommet into place into a quarter-wave, 23.2 inches from cen- to one long edge of the dowel, with the pipe and over the rounded part ter hole to leg end. Drill the ground one end flush to the drilled end of of the dowel. Pipe-glue a cap onto plane legs and the mounting plate to the dowel and the other end flush the top of the pipe. match, making sure that the ground just below the milled rounded end of • test the antenna by mounting the legs don’t interfere with the plastic the dowel. Affix the shorter piece of antenna onto a pipe and into the air mounting fitting. tape on the opposite long edge of the above any other conductors. Hook a • note from the photos that the dowel with one end of the tape flush to BNC cable between the radio and the ground plane legs can be mounted the drilled end of the dowel. The other antenna and listen for distant stations. with a single or double screw/nut end of the tape should be well short of That’s it for this month. This antenna assembly. Assemble the legs to the the rounded end of the dowel. was really built on the principle that mounting plate. • Carefully place the dowel drilled end necessity is a mother. The new engineer- • the support braces are not electrically over the center pin of the BNC connec- ing lab needed a test antenna and I always necessary, but those wide legs flop tor on the PVC fitting. Cut the three- wanted to build the ultimate ground around in the wind a lot. The braces are quarter inch pipe so that there will plane. While I was at it, I built a second just there for mechanical support, and be less than one-quarter inch of free antenna for the amateur two-meter band can be placed anywhere on the legs. space at the top of the pipe. with exactly the same methods and it • to equalize the response of the antenna • Use an awl or icepick to put a small works perfectly. This is the ultimate “stay across the band, calculate midway hole in the exact center of the copper tuned”. See you next month. J

The two-screw ground plane strap mounting to the plate and the plastic mounting mast bracket for use with a worm clamp mast bracket mounting. (Right). The same thing with a single-screw ground plane strap mounting and the narrower straps on a higher frequency (two-meter) ham radio antenna.

KITPLANES May 2014 79 By Robrucha

80 KITPLANES May 2014 www.kitplanes.com & www.facebook.com/kitplanes