Vibrations

[Bavo]

Hi all,

I had to do an emergency auto rotation because my motor stopped in the middle of a tic toc about 15 feet up.
The heli landed on the skids but bounced pretty hard because I didn't have enough headspeed for a nice flare. At first sight there was no damage, but I have a vibration on the tail ever since then.
I can clearly see the tailcase vibrate in the at 1600 RPM, if I go to 1900 I the amplitude is a lot smaller but you start to hear it.
I have replaced the main shaft and tail shaft, without any result, I still have a spindle and tailspindle lying around so I could try to change those, but I'm starting to think is the Torque tube?

Does any of you have some suggestions about what it might be?

[paulmedford]

Check tail blades as well, recheck that the bearings in the torque tube didn't move.

[rcmarty]

Check the boom for a slight bend

I'd also pop off the tail case and pull out the tt

I had a crash with mine and found one of the bearing holders had split apart. ( little plastic half housings that glue to either side of bearing. Then o ring slips over the 2 pieces )

I'd imagine is a holder split apart ( easy fix with a little ca ) but won't do it's job.

Don't forget there's a spindle on the tail rotor.

Check over the tail carefully also. I had a mild hit on the tail ( fin busted up but blades mint ) and I found the slider while looks perfect binds when assembled.


Martin

[Bavo]

Last night I removed the torque tube + tail, everything looked perfectly straight + all of the bearings were intact. The only thing I noticed is that the bolts that keep the carbon rods connected to the vertical stabiliser were pretty loose, this can be caused by the vabritions, or coult it be the cause?

Checked the vibration log for the fist time on the bench, without tail (no main blades!), no vibes.
Reassembled the tail again and checked the vibration log again (no main or tailblades), no vibes.
I will do another testflight after work today, will keep you guys posted...