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armondo

Active Member
After flying the same RV6 since 1996 (1500 hours plus), recently between the speeds of 33 miles an hour to 36 miles an hour, there is a vibration that appears. I have checked wheel pants, tires, bearings, have found no explanation. Am I the only one with this problem. If you know the answer, let me know before I end up on my shrink's couch. Armondo
 
Had a cyclic pulling, vibration

It felt like my brake disc was warped. Pulled the pants to investigate and found one of the 3 #4 bolts was missing that holds the wheel halves together. That would have been a bad day if one of the other ones let go. 1200 hours since new and original bolts. All bolts have been replaced and will do again every 500 hours.

Steve
 
Shaking tire

Tires can wear uneven leaving them out of balance. I rotated my tires and got a huge shake and found the left one way out of balance. Had to put 1.5 ounces on it!
 
Mine has developed gear leg / wheel shake in the past couple months. Most noticeable when I slow down after a wheel landing. Speeds about the same mid 30's fast taxi. My tires are half worn out and I flipped them around on the rims at last annual to even out the wear. Methinks it's just time for new ones again.
 
Did you try flying it without the pants on? (Eliminates the pants as a problem.)

Did you check wheel alignment? Toe in or toe out might cause shimmy at certain speeds. If the gear legs are sagging a bit with age, alignment might be a bit out.

Does braking affect the shimmy?

The 1st -4 I owned never had shimmy at all; the one I currently own will shimmy a bit at roughly those speeds on pavement.

Charlie
 
me too

it happens, have seen more in the winter than summer. Just balance or replace tires. You already checked for other issues. Also I use and like the wood leg stiffeners. Can be put under leg fairings. Stops or reduces most common shimmy (front to back). But you can still get some shimmy, even with stiffeners.
 
don't forget the tail wheel

Just replaced the tail wheel bearings to eliminate a buzz/vibration. Has it been more than a couple of years since you changed those bearings?
 
Shimmy

At 31 knots I developed a vibration in the nose wheel. Pretty violent. Went Anti-Spalt bearings and balance, flew with the wheel pant on and off, no change in the vibration.

Had a friend chase me down the taxi way up to 35 knts and take a video with his iPhone. The left main gear started to shimmy so bad that it set up a sympathetic harmonic to the right main gear, which transferred to the nose gear. Quite educational.

Placed the wooden/fiberglass fix on both main gears, and added Sun-Tech Innovations dynamic wheel balancer to the left main gear. Solved the problem.

I do recommend the folks at Anti-Splat and Chris at Sun-Tech.

Hope this helps.
 
At 31 knots I developed a vibration in the nose wheel. Pretty violent. Went Anti-Spalt bearings and balance, flew with the wheel pant on and off, no change in the vibration.

Had a friend chase me down the taxi way up to 35 knts and take a video with his iPhone. The left main gear started to shimmy so bad that it set up a sympathetic harmonic to the right main gear, which transferred to the nose gear. Quite educational.

Placed the wooden/fiberglass fix on both main gears, and added Sun-Tech Innovations dynamic wheel balancer to the left main gear. Solved the problem.

I do recommend the folks at Anti-Splat and Chris at Sun-Tech.

Hope this helps.
 
I had a shimmy

I flew mine for about 500 hours with no problem at all. Then I started getting a shimmy slowing down on landing. I went crazy with it. Put the leg stiffiners on, no change. Changed tires, etc. it got worse and worse. Finally I tried new rotors. Problem solved. They caused a shimmy even when not touching the brakes. With the new rotors it was like a new plane.
 
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