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Rudder pedal vibration

J

Jeff Wilde

Member
Greetings, I have an issue with my rudder pedals vibrating in flight. I have searched the forum and I have not seen anyone mention rudder pedal vibrations. I do know that vibrations can be felt from this engine as it is not perfectly smooth. I have seen it mentioned being felt in the stick and while touching the panal. I have very little panal or stick vibes but enough vibes in the rudder pedals that it is annoying. I have balanced my carbs, dynamically balanced my prop (new prop hub), and my front tire is not spinning in flight. I have a gasket on the front lip of my canopy. Have others out there had the same experience and just not mentioned it. If so, is there a cure? I have 40hrs on my RV12 and continue to tweak. I am really enjoying it. Jeff in Geneva Florida
 
If you have a ground adjustable prop make sure both blades are at same pitch. The way I do this is I have a lazer level and with the prop in a horizontil position I place the level against the backside of the blade and shine lazer to the floor. Mark the spot and now do the other blade. This is very accurate and just a very little differance makes the vibration noticeable and on my S7S it also vibrates the windshield.

Ollie
 
Ollie said:
If you have a ground adjustable prop make sure both blades are at same pitch. The way I do this is I have a lazer level and with the prop in a horizontil position I place the level against the backside of the blade and shine lazer to the floor. Mark the spot and now do the other blade. This is very accurate and just a very little differance makes the vibration noticeable and on my S7S it also vibrates the windshield.

Ollie
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Hi Ollie, I did this with my lazar level and they are within .1deg of each other. I think my main question is, is anyone else having vibrations coming through their rudder pedals? I can feel slight vibes coming through my panal and stick but a bit of buzz through the rudder pedals. My neighbor suggested that it could be flutter but it does not seem to change when putting pressure on right or left rudder pressure. It seems pretty constant. It diminishes some at full power and is most noticable at 4600 to 5000rpm. I know the vibration issue has been pretty well talked about here but no mention of rudder pedal vibes. BTW, you are no too far from me at Loves Landing. In fact, do you fly your S7S to Cedar Knoll for the breakfast? I am at FD92 underneath Sanfords class C.
 
Jeff,

Is the vibration ONLY in fliight? If you do a ground runup and very slowly increase the RPM's does the vibration occur, perhaps at a certain RPM? It sounds like there is a sympathetic vibration at work here. In flight, if you pull the pedals back to slacken the cables, does the vibration stop or continue?

How was your dynamic prop balance done? Was it accomplished with a high quality instrument in exoerienced hands?

Just a few questions to provoke thought.

John
 
BigJohn said:
Jeff,

Is the vibration ONLY in fliight? If you do a ground runup and very slowly increase the RPM's does the vibration occur, perhaps at a certain RPM? It sounds like there is a sympathetic vibration at work here. In flight, if you pull the pedals back to slacken the cables, does the vibration stop or continue?

How was your dynamic prop balance done? Was it accomplished with a high quality instrument in exoerienced hands?

Just a few questions to provoke thought.

John
Click to expand...
John, when I'm on the ground with the throttle wound up I'm either taking off or have the brakes on. I cannot feel any vibes in either of these configurations. I guess I could chock the wheels and tie the tail and check that out. I will do that and report back.

About my prop balancer. It's a cheapy but seems to work OK. I have used it before and it worked great. Honest, I don't suspect my prop balancer but will keep this in mind.

I will also pull the pedals back in flight and give that a try.

I guess that it is somewhat unusual to have a relatively smooth engine with buzzing pedals.

Thanks for your reply. Jeff
 
Exhaust pulses on the floorboards? Have felt this on other RV models albeit with different exhaust pipe outlets /tunnels.
 
Rotating wheels can cause vibration. Have the wheel bearings been tightened according to the Matco manual? Unlike wheel bearings on a car that turn freely, the Matco wheel bearings should have some drag, 8 to 10 inch-pounds of torque according to the manual.
Joe Gores
 
Jeff Wilde said:
.....About my prop balancer. It's a cheapy but seems to work OK. I have used it before and it worked great. Honest, I don't suspect my prop balancer but will keep this in mind......
Click to expand...

You are getting a lot of good suggestions above. All I can say about prop balancing is that it made a HUGE difference on my airplane.
 
Mich48041 said:
Rotating wheels can cause vibration. Have the wheel bearings been tightened according to the Matco manual? Unlike wheel bearings on a car that turn freely, the Matco wheel bearings should have some drag, 8 to 10 inch-pounds of torque according to the manual.
Joe Gores
Click to expand...
My wheels do not spin in flight. The front wheel had enough friction to keep it from spinning in flight. In fact, I had enough pinch on the bearings that it appears I damaged the rubber seal on one of the bearings and it was damaged. When I get the new bearing I will balance the wheel instead of relying on pinch to keep it from spinning.
 
Vibrations greatly diminished

BigJohn said:
You are getting a lot of good suggestions above. All I can say about prop balancing is that it made a HUGE difference on my airplane.
Click to expand...
Well Big John, I took your advice and had a trained professional do my a dynamic balance. I saw Arnold Holmes mentioned somewhere on the forum and he runs Av-Mech LLC at the Leesburg International airport in central Florida. I flew out to his hanger there and he did an excellent job of balancing my prop. I mention his name because I feel a good bit of relief and satisfaction at his workmanship. My inexpensive prop balancer said I was about .04ips, a pretty good reading. His initial reading was above .2ips. Significantly different than my reading. Not too bad a reading but I believe that on our light airframe it translates vibes through the fusalage significantly more. Well, the final balance was less than .03ips. There was a significant seat of the pants improvement. I am very pleased with the result. Thanks for all your help out there. Jeff in Geneva Florida
 
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