Tail vibes

[GeorgiaBoy]

I know you folks are sick of this subject, I did a search and couldn't find my exact situation. Brand new 500 build has a tail vibe. It is not a wag but a high speed vibration. I disengaged the belt for head spinup only and it was smooth. I balanced the tail rotor assembly, still vibe. I removed tail assembly so only the shaft was spinning and still got the vibe. I think it is the belt doing such a long run that it builds up. Anyone have input? Thanks.

[dfgipe]

Without seeing the heli, are your boom supports glued in securely? They dampen alot of vibration and if not glued, the boom can vibrate. I had this happen on a 450.Just an idea. If it was because of the length of the belt, then all 500s would vibrate at the tail.Check your supports.Hope you figure it out.

[755 robert]

Maybe a twist in the belt??I Had a bad vibe in my 600 it turned out to be a roll in the belt,not an extra twist,a roll..Just a thought..

[GeorgiaBoy]

Thanks guys, the boom supports are not glued so I'll remedy that. I have double checked the belt for one too many twists but am not familiar with the roll. Could you please expound on that? I agree that this would drive every 500 owner to torque tube so I'm looking for answers. I considered installing tension rollers in the boom but if it was needed then it would be part of some upgrade already. Thanks.

[755 robert]

Originally Posted by GeorgiaBoy

I have double checked the belt for one too many twists but am not familiar with the roll. Could you please expound on that? Thanks.

It's kinda hard to describe but I will try.The belt has the 1/4 twist between the front and rear pulleys,you can also get a roll in the belt,if you hold the belt between your fingers and roll the belt it will become a "mobius strip"Look at this .. I hope this helps..
[
I hope this link works..
https://www.google.com/search?q=mobi...w=1024&bih=653

[GeorgiaBoy]

Thanks Robert, kinda curious about the "mobius strip" til I asked about John. Got it. I'll check again but call myself eliminating that. I used a flashlight to check but will go back thru. I do wonder if the belt is vibing enough to rub in the tail from the long travel.
BTW, I'd ask the big guy but he has enough to carry.

[755 robert]

I am not explaining it very well,if you roll a rubber band between your fingers it will do what I am trying to explain. I have seen a number of the bigger belted helis with this issue...Correct tension is very important as well..

[dfgipe]

Well at this point, if the belt is flapping against the inside of the boom then the belt needs to have more tension on it I would imagine.And you're right about tensioners, don't think you want to go there!

[dfgipe]

Ok Robert, you type faster than I do! lol Check the belt tension.

[dfgipe]

Georgia Boy, just another thought. Might want to post on the T-rex 500 forum and see what they think. Good luck.