Author: Mike Riggs
Edition: Model Aviation - 2011/11
Page Numbers: 102,103,104
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Radio Control Aerobatics

Trying something new can be a game-changer

Mike Riggs

CONGRATULATIONS to Team USA and its 2011 FAI F3A World Championship first-place finish. Team USA members Andrew Jesky, Chip Hyde, and Brett Wickizer finished individually in third, fourth, and 12th place, respectively. Congratulations also to Christophe Paysant-Leroux of France for his F3A first-place finish and to Tetsuo Onda of Japan for his second-place finish. Semifinal scores were used as a tiebreaker for first and second places. I did not attend the event, but from the scores it appears the caliber of flying was unbelievable.

A "game changer" can be a visionary or a strategist who uses creative innovation to alter "the game." The game to which I refer is RC Pattern Aerobatics; the prospective game-changer is the innovative Contra Drive.

The idea of developing Contra Drive for precision aerobatics began with discussions between Brenner Sharp, a principal engineer for Whirlpool Corporation, and Mike Gaishin, owner of Gaishin Manufacturing. After discussing the original Contra Drive designed by Michael Ramel and flown by Silvestri Sabatini in Europe, Mike offered to manufacture a "made in America" Contra Drive if Brenner would design one. Brenner completed initial design work for the Contra Drive in the fall of 2009. With Mike Gaishin handling the milling and his son Andy handling the lathe work, the first prototypes were constructed during the winter/spring of 2009–2010. Contra Drive was debuted by Brenner and Mike at the 2010 RC Aerobatics Nationals.

The fundamental aerodynamic concept of the Contra Drive is to cancel the asymmetric blade effect (P-factor) of one spinning propeller by spinning another propeller in the opposite direction. Brenner describes this as absorption of power, effectively canceling trim changes as airspeed changes. Pilot workload is greatly reduced because torque effects are canceled and absorbed regardless of the airplane's attitude.

Contra Drive designer Brenner Sharp finished 12th in Masters—matching his highest Nationals finish in one of the most competitive fields in years. Contra Drive fabricator Mike Gaishin finished eighth in Intermediate. The partnership of Brenner, Mike, and Andy continues to make improvements to Contra Drive. Version two is currently available with changeable gear sets and a variety of propeller sizes.

In preparation for this column, I asked those on the National Society of Radio Controlled Aerobatics (NSRCA) mailing list for help coming up with a list of historic Pattern game-changers. Someone inferred that former RC Aerobatics columnist Ron Van Putte was flying Pattern before air was invented. The list included such innovations as:

  • Proportional radios (computer-mixable radios)
  • Retractable landing gear
  • Tuned pipes
  • Four-stroke engines
  • Rubber isolation mounts
  • Electric motors

With the Contra Drive costing more than $1,000, I doubt the lower classes in which I fly will be seeing Contra Drive in numbers anytime soon. However, for the fierce competitor looking for that competitive edge, Contra Drive may be a ticket to the podium. History will tell us if Contra Drive joins the long list of game-changing innovations dating back to the beginnings of RC Aerobatics, when competitors flew horizontal patterns with single-channel airplanes.

Before the weather gets too cold to paint, my building-season plans include putting a finish on my Black Magic, which has been waiting for paint since the end of last building season. The current (August) plan is to MonoKote the wings and horizontal stabilizer. The fuselage and rudder will be fiberglassed, primed, and painted.

My choice of paint hasn't been decided. I have had good results using Klass Kote epoxy paint without clear coat. Using polyurethane clear coat over water-based paint is also being considered.

My microbiologist wife appreciates Klass Kote not containing isocyanates (something about isocyanates being bad for my health). My only problem with Klass Kote is waiting for it to become tack-free in my less-than-dust-free garage. Tack-free in 15 to 20 minutes has been my experience. Klass Kote is a great product; the environment in which I spray is the problem.

The idea of using water-based paint is intriguing to me. Not only does water-based paint offer easy cleanup, a heat gun can make it tack-free.

The canopy on my Insight is coated with water-based paint. Specifically, the transparent blue and underlying silver sparkle is Faskolor paint, commonly used on Lexan RC car bodies.

Painting the Insight canopy was a calamity. With the best intentions, the glassed and primed canopy was sprayed with Klass Kote silver. After masking a canopy frame, the remaining exposed silver was wet-sanded with 320 wet/dry sandpaper.

Faskolor transparent blue was sprayed directly over the masked silver using an airbrush. Between light coats, I used a heat gun to dry the paint. When dry, the sheen was flat but the paint looked great. Isopropyl alcohol was used for both paint-thinning and equipment cleanup.

After waiting 24 hours, I sprayed the unmasked canopy with a thinned coat of Klass Kote clear. Bad move on my part. I was horrified with the "fish-eye" (dimpled) finish left behind. After a short wait I followed up with another, much thinner coat of Klass Kote clear, making the results even worse.

After progressing through several stages of denial, the canopy was wet-sanded down to the Klass Kote silver undercoat. Thinking that preparation was the problem, I used the same process again and got the same disastrous results.

My friend Lorin Finney told me epoxy paints react to moisture in the underlying water-based paint. Polyurethane (isocyanate) clears actually contain moisture and that is why they are the clear-coat choice of many professional painters.

With knowledge gained, the canopy was again sanded down and painted—this time with frustration running high and a need to fly. Rattle-can clear lacquer from the local home improvement center was used for the clear coat. The finish is not perfect, but it was cheap, fast, and presentable. I hope you do not make the same mistakes I did.

I have not decided which paint I will use on my Black Magic. Look for an update in the future.

My main goal for this building season is to build an RC airplane with my daughter. Mary wasn't interested in buying an ARF. She insisted on building a balsa wood airplane in my (our) workshop. At least I succeeded in getting her to agree to build from a short kit instead of plans. Perhaps in the future, Mary and her Super Scratch will be Sportsman of the Month.

I am running low (aka empty) on Sportsman of the Month nominees. Since the pictures of my Honda Element in the July 2011 issue drew an overwhelming response, I am expanding reader contributions to include Hauler of the Month. Please send a picture and caption of your Sportsman of the Month or Hauler of the Month.

Flight complete. MA

Sources

Transcribed from original scans by AI. Minor OCR errors may remain.