RE: DA Engine & DP Edge
50cc is perfect. I just had the best flying weekend all season with my DPM Extra DA50 combo. I believe the flutter is due to linkage set up and servo torque. I'm using 180 oz. servos one each in the aileron. You may also want to increase the prop dim. and lower the pitch. I was pushing this plane with a 23 x 8 mejzlik prop doing full throttle low passes and was rock solid. Not even a hint of flutter.
Baddog,
Hope you get it sorted out. These planes are a blast and the thrust to weight ratio is awesome. At least 2 to 1. Go with the higher torque servos you wont regret it.
Oh, and you wont have to stop by the LHS spend $25 for a gallon of 25%-30% glow fuel and have to spend 30 minutes cleaning up the glow mess at the end of the day.
Gassers Rule.