Dave,
I'm a JR guy so by Flaperons do you mean that the ailerons move oppisite the elevator when you apply elevator control?
I took my Webra .61 out of my plane and installed a Magnum 91 in the plane It really rocks now. Almost scarry vertical. I have had flame outs with the engine at Idle in a tight dive recovery pulling to verticle. I suspect that it is the high tank location pushing too much fuel to the engine under the added G load so it loads up rich and quits.
Sparky