I have over 50 flights using the HD 1501MG servos on a 3D profile plane .52 cu in nitro engine. The servos have been totured with constant movement, and a high "Work Load"; 50 to 60 degree deflection on some surfaces and has performed flawlessly.This order is my second order for these servos., but not my last. These will go in a EXTRA 300S - with a .91 size nitro engine.