OldRCer

At what speed are you flying when the Stamp is rocking side to side, or is it at all speeds? After takeoff and when they are at reduced speed the Stamp should be very stable. All that I have flown and seen fly appeared to be stable at slow speeds. At high speeds they are liable to do anything. At slow speed with its nose up in the air it is as stable as any plane can be. When you say rocking, is it like the ailerons are being moved? Are your elevon servos mounted in the rear with short push rods? This is an interesting problem and we need to figure it out.