gow589, Thanks for the response. Based on that, I may try 4 ailerons. The linkage you showed was similar to what Bill Evans used on his Astron-40 X-wing tail-less bipe back in 1979. It worked well, but I would not use that method on something as big as the Phaeton 90 when good servos are so cheap these days. The twin 20cc Stinger looks really nice on your Phaeton 90 and I bet it is really smooth. Looking up the weights, I see the Stinger 20 cc twin is just 2.06 pounds and my Enya R120-4C engine weighs 2.0 pounds, so essentially the same weight. I have a Singer 20RE single cylinder that would fit the Phaeton 90 quite nicely too, but just out of morbid curiosity, I think I will stay with the Enya to see how many more years I can get out of it. 35 years, two set of bearings and still counting... going for 40.