Aileron vibration

P

PhilW

New member
While recently flying his Cruisemaster (14-19-2; 0470) my friend experienced a momentary vibration through the control column. He was flying at cruise speed, and had initiated a moderate bank and pull-up when he felt the vibration. The instant he released the maneuver the vibration stopped. He tried it once again and got the same effect; he didn't try it again.

The obvious possibility is the trim tab, but his tab has about as little play as the mechanism will allow and is well within tolerance.

Any thoughts?

Phil
 
Please do not consider my comments authoritative in any respect, but I think this is a serious issue and we would like to stay with the topic until the root cause is identified.

If the control surfaces do not have any out of tolerance play, I would look to other problems elsewhere in the empennage. I would check the tension on the flying wires that support the horizontal stabilizer. Are all four flying wire battens in place - top and bottom? Any damage history that maybe wasn't repaired properly?

Your topic title mentions aileron vibration. Was the vibration attenuated when the aileron pressures were neutralized or was the vibration associated with the elevator? Maybe this was hard to determine. Sympathetic vibrations can sometimes occur that are really hard to track down. For example if the fuselage fabric was developing the "drumbeat" type of vibration that might have resonated with one of the control surfaces. I would definitely seek the advice of one of the experienced Bellanca A&P gurus. They are not very active on this forum.

Please understand that this is speculation only, but if this condition is determined to be control surface flutter it's a problem not to be messed with. Please keep up advised... Rob
 
On my 14-19-2 the bolt holding the aileron counter weight to the aileron wore to the point that the weight could move independently of the aileron. It is easy to check, just hold the aileron in the up position and gently push up on the counter weight.
 
I know this is not the same but twenty years ago I was into radio controlled airplanes, had a nice 1/4 scale one that got a aileron vibration on a dive, before I knew what had happened the wing blew apart and it crashed to the ground. So my thoughts are you better find what the cause is so this does not happen to a real one.
 
It appears to me that you need to take a knowledgeable observer along for a test run. If you are sensing this through the controls, then it must be connected with aileron,elevator or trim tab. A person looking at these when it happens may be able to narrow the source. I have had excessive play in the ailerons but never a vibration. I re bushed all of the aileron hinges getting rid of the play, yet never noticed any difference in flight. My trim tab has very little play. Trim tabs are a common problem for control vibrations. Lynn the crate
 
This may seem off of the wall, but check your motor mounts. A climbing turn puts a little extra G-force and could make the motor move just enough to cause a vibration. It is not common, but it is possible and should be one of the things considered. Please let us know what it turns out to be. ___Grant.
 
Hi Guys, my friend Doug Wilson - he's now the sole owner (sob!) of CF-EDW - flew the plane a couple days ago. It was the first time he had flown it since experiencing the vibration I wrote about earlier.

After trying a few different things, he found that the vibration occurred when banking sharply. He could clearly see the movement in the ailerons; especially the 'up' aileron (greatest deflection?). He also noted the flaps could become slightly involved.

Rapid pitch changes did nothing.

On examination some play was found in the aileron hinges, especially the outboard hinges.

Doug will be flying the plane to Osh next week. Before then he'll have the ailerons off and the hinges rebushed (or whatever it takes).

Thanks for your suggestions and comments...it's a great forum!
 
Thanks for the update on this issue. I would be interested to know how much play exists at the trailing edge of the aileron both before and after the hinge fix. To my knowledge there are several places in the aileron attachment and control system that will contribute to the play. It would be useful to know how much improvement is attributed to the hinge area. Thanks, Rob
 
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