FBL Gyro Has anyone noticed this...

Bruno

Member
I have an AR7200BX on my Trex 550E DFC V2.

I have been flying this setup at least 50 times without any issue. She is stable and hovers very steady without any stick movement (centered sticks).

Set-up:
Tail pitch slider set-up is centered at 90 degrees/perpendicular to the tail shaft with about 10mm tail rotor differential to correct for tail right/nose left movement.

Observation:
After initialization of the BX, I typically hit rate mode to center the tail slider, put her back in HH mode and spool up gradually and right before mid stick I throttle up and take flight.

However, I recently noticed (never paid attention to this before) if I leave her on the ground/concrete while I spool up to about 50% idle and a bit negative collective pitch (about 2 degrees), the tail slider may move to the left (tail left/nose right) without stick input. This does not happen every time.

If I correct for the movement she will stay centered and hold there indefinitely.

Question: Any ideas as to what is going on here with the independent slider movement? :emomad:
 
Last edited:

Derek

Well-Known Member
I have the AR7200bx also but I haven't had a chance to install it on anything yet. I'm curious if the gyro is sensing a vibration, therefore trying to compensate for it. Giving the slight negative collective, while on the ground, would push the heli down...possibly causing a vibration that you never noticed before because you usually throttle up and then take off.

I'm surely no "gyro guru" but it's just a thought.
 

pvolcko

Well-Known Member
I have not seen this behavior, but I don't leave it on the ground that long generally. If this is recently happening you may want to inspect bearing to make sure they are spinning smooth and give a drop of oil to them if you haven't before.
 
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