Boom Bounce
 

I have experienced what I believe is boom bounce with my 336. Happens around 125 mph. From reading earlier messages, seems like it could be due to excess play in elevator trim, etc.
No flutter in controls, just a rocking feeling in the seat and could see the boom vibrating at that speed. Ok below and above 125. any additional input would be appreciated.

just a thought, i needed to replace the bolts on the elevator attachment fittings, they had
just a very slight wear. replacing the bolts cured the problems, and it is very easy to
do. didn't take me 1/2 hour. i could not believe that such slight wear could cause that.

I had this happen as well but it was at cruise speeds. Anyway, my IA said he felt the cause was the cable tensions in the elevator were out of tolerance. He made the appropriate adjustments and I have not experienced this again. It has been probably 5 years now.

Ed

I found the culprit to be improperly torqued attatchig hardware. The elevator itself is in a low frequency flutter. This could be problematic if left to it's own devices but I found that a change in rear prop RPM would throw the flutter out of phase and interupt the cycle for a while. Anyway two minutes with the end wrenches fixes the problem. One should note that most mechanics fear over tightening the bearings and will not quite finish the job. So a bit more than snug doesthe trick.

_travis

Boom Bounce
 

Thanks For The Help, Tightened The Elevator Hinge Bolts Which Took The Play Out And All Is Fine.