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wheel shimmy

J

jacksel

Well Known Member
I finished my RV-6 in 2005. It's got the newer style wheel fairings. I periodically experience shimmy in one or both main gear during landing and occasionally during taxi. I heard this can be remedied by installing counterweights in the forward wheel fairing half. Is this true? And is there a generally accepted technique for accomplishing this? Thanks.
 
Weighted fairings

On my 6A, way back when, I read about putting lead shot and epoxy in the nose of the wheel fairings and 'balancing them' so as to prevent shimmy.

So,I did this years ago and still get occasional shimmy.

Every nose-dragger RV I've ever flown seems to have a harmonic / shimmy speed from time to time.
 
jacksel said:
I finished my RV-6 in 2005. It's got the newer style wheel fairings. I periodically experience shimmy in one or both main gear during landing and occasionally during taxi. I heard this can be remedied by installing counterweights in the forward wheel fairing half. Is this true? And is there a generally accepted technique for accomplishing this? Thanks.
Click to expand...

I balanced mine when I built the plane. Essentially, I poured lead shot and epoxy into the nose of the pant, then laid a layer or two of glass over it. Despite that, I still get shimmy.

What seems to correct the issue for a while is to use new tires/tubes. Presumably, they are better balanced than a hundred hour old set. Tire pressures help too. I do not have the stiffeners installed.
 
It may not be shimmy. Have someone competent look at the tire when it is doing it.

Most likely it is a tire out of round or Balance or both.
 
Shimmy

I too balanced my wheel pants to help stop my gear legs from shimmying. Gear leg stiffener put on during the build. After balanced still got some shimmying but better. Then I started playing around with tire pressure. Going up to 30lbs bad news, going down to 18lbs fixed the problem but the tires looked flat and the plane was a bitch to push around :mad:. Then I started working my way up in tire pressure to find the sweet spot. I'm now at 25 lbs and NO shimmy :D. Plan on going up a pound at a time to find out where is to high. But at 25 lbs tires look okay and not so bad to move around now. This may all change when my tires start wearing down some, time will tell. Good luck.
 
If you have tire shimmy, try a good set of tires like the lower priced GoodYears. I start mine off with 35# and catch them at about 18#. No shimmy, no wood stiffeners, no balanced pants.
RV6A.
 
Ditto with Gasman..... Use to get the shimmy every now and then but all went away when I changed tires. I do have the wood stiffners on both mains and nose.
 
I get shimmy when the tires are overinflated (above 38#). At 38# or lower, no problem. Using Goodyear Flight Custom III and balanced.

Mark
 
mrreddick said:
Did you install the stiffeners on the gear legs?
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I did not install the stiffeners. I guess I was just hoping to get lucky. I do prefer to operate with higher tire pressures. Makes the airplane easier to move and gives the fairings a little extra ground clearance. From the responses I'm getting, I think I might go ahead with the stiffeners. Is there a preferred type of wood to use? From the plans, it looks like you bond it permanently to the gear leg.
 
jacksel said:
From the responses I'm getting, I think I might go ahead with the stiffeners. Is there a preferred type of wood to use? From the plans, it looks like you bond it permanently to the gear leg.
Click to expand...

Before you do that may I suggest you do two things....

Check the roundness of the tires

Balance both main wheel/tire sets.

Both of these can have a major impact on shimmy tendency's in rod style gear legs.

Let us know how it goes
 
What Scott says......... But if you are close to needing tires, then wait and try these........
http://www.aircraftspruce.com/catalog/lgpages/gy_tires.php

Flight special II 5.00-5 p# 06-07110

They wear like iron, and stay round. Mine are smooth as silk..................... And I also had a shimmy problem!!

No stiffeners installed to date. Just not needed.
 
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Be sure to

align the red dots on your tires and tubes when they are installed. This will help prevent an out of balance condition. The reason shimmy goes away at lower tire pressures is because a scrubbing action is pulling on the gear legs causing them to drag along the pavement or grass. The only downside with this solution is you will be replacing tires about every 50 hours.
 
Shiimy

I had some shimmy in my long gear RV-4 while slowing during landing roll at just about taxi speed. Was using 30 PSI in the tires. Now using 35-40 PSI and the shimmy is gone.
 
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