Hello, I have been flying my N7 for three years now, awesome machine. Recently I crashed the machine exploring to low to the ground LOL, I rebuilt the unit flew great. "Practicing new maneuver" and crashed tail first into the ground, I had activated throttle hold both times, so I did not experience full power crash. After inspecting the crash, boom was slightly bent, broke the main blades, tail blades were in one piece except were the blade grips slammed in them, transmission box gear was split in two and the engine was idling on throttle hold and on its landing gear which was not broke, so a pretty slow crash. "Here is were the journey begins," I replaced the boom, tail shaft, bearings, main shaft and bearings, feather shaft, transmission gear, torque tube and pieces, new tail blades and main. In this crash the boom supports and control rod were not damaged. Took machine for a test flight, blades tracking nice, no unusual vibration from the engine etc. In forward flight the tail shutters violently back and forth, perform a punch out tail holds great etc. So, removed tail servo and installed a new one same problem, removed CGY750 and installed a know good one that has not been crashed, same problem. Ordered parts to completely rebuild the transmission box to the back of the tail. Took unit for another flight same problem, tail shutters in high speed forward flight.
Equipment: CGY750 with new software, BK coreless servos DS7006 tail and three DS7002. Running standards setting on rudder in the CGY unit. I had even played with the gain setting. OS105 engine.
I am at frustration point, I looking for some ideas or suggestions, I am the only one at my field flying helicopters so I really have no one to ask? Thanks for the help......
