November 23, 2024, 06:31:56 AM

Author Topic: N7 Tail Shutters in Forward flight  (Read 1211 times)

Offline tsky70

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N7 Tail Shutters in Forward flight
« on: August 22, 2018, 06:03:49 PM »
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......

Offline Grimmy

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Re: N7 Tail Shutters in Forward flight
« Reply #1 on: August 23, 2018, 08:41:11 AM »
Have you tried a new tail rotor hub?  Just remember reading about some people with tail issues, to find out the hub was bent.  Being that you did crash, tail first.

Offline tsky70

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Re: N7 Tail Shutters in Forward flight
« Reply #2 on: August 23, 2018, 10:35:41 AM »
Thank you for the reply, I did install a new tail hub.

Offline JamesRC

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Re: N7 Tail Shutters in Forward flight
« Reply #3 on: August 23, 2018, 06:53:53 PM »
Interesting it doesn't happen on a climbout but only in FFF.  I take it in hover there's no problem as well?  Don't suppose you could get a video?

Offline p johnston

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Re: N7 Tail Shutters in Forward flight
« Reply #4 on: August 26, 2018, 06:44:34 PM »
Are you sure your boom support ends are still tight and haven’t come unglued? You said they are fine but loose ends would cause that issue your having.