Play in tail - vibration

[MiniCwik]

Hopefully someone will be able to help in suggesting what I can do to resolve a vibration problem I have.

I recently noticed the horizontal tail stabilizer fin on my HDX/Trex hybrid heli was vibrating at more than half-stick while in a hover and slow FF. Searching through the tail assembly I found an area that I think is causing the problem.

The tail sprocket gear has a small gap on either side of it within the tail case, and if I grab the tail blade grips and push towards the tail case or pull away from the tail case I can move that sprocket within the case :shock:. So I think as I increase rotational speeds this play is causing a vibe to come up through the tailboom to the fin, and then to my gyro which I want to alleviate.

Here is a pic I am borrowing from another HDX450 thread that shows where the gaps are, what can I do to resolve this movement? Install a washer between the sprocket and the bearing, or the bearing and the tail case, or is this excessive bearing play which requires new bearings?

Thanks!

[zed]

ive got the same amount of spacing on my 450, but no vibration. i did have a slight vibration from a slightly bent main shaft(oh so slight). i wander if your belt is to loose?

[MiniCwik]

Thanks zed, I took her down to my LHS and had the heli guy look at it and he was willing to bet the problem was due to sever(ly) out of balance stock white tail rotor blades. He removed my stock white blades and tested their balance with the ole bolt through the roots and WHOA were they grossly different.

So I sprung for the Align tail rotor blades here;
http://www.align.com.tw/shop/images/function/hs1208_1.jpg
He also pointed out that my tail belt could be a little tighter but it was not too loose, so I will also address that.

I'll test her out tonight, but after seeing how bad they were out of balance I am willing to bet he was right on. Lesson learned, always, I mean always balance all of the blades, not just the main one's.

We would have test hovered in the store, but I didn't bring my TX or battery with the heli today, dohhhh my fault there. I enjoyed the three AxeCP guys who came in though and were drooling all over my heli though :YeaBaby: