Yay I finally got to fly the Viper and meet
speedracerntrixie on Sunday! Thanks for the tips! After you left, I did 3 more flights. I continued with the 9x7 as we couldn't find another to try. The engine seemed to do better each time - it seems to be breaking in nicely, and generating less heat.
I need to nail down a couple of quirks though. The engine mounting screws, all 8 of them, kept coming loose. I think I am going to JB-weld the inside ones in, as that gets tiring fast. The outer bolts seemed fine after tightening them when the engine was warm.
Also, the wing mounting bolts were coming loose. I may convert them to 1/4" nylon but for now I will just check them after each flight, no biggie.
I increased the aileron travel as much as possible and the roll authority is still minimal. Playing with the detached wing in hand, I could feel it really "fight the roll". With practice, I can manage it.
I re-measured the CG at about 3 1/3 inches, which felt just fine. My final landing of the day was best, and managed a nice flare and graceful touchdown. Those big wheels saved the day twice from gopher holes and dirt mounds. No broken props and 2 landings finished with the engine still running.
I've got some 9x6 props on the way, including a couple wooden ones to try. It may be a while before I get more flying time though, I think my next 2 weekends are booked up... wah.
