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  #1  
Old 11-12-2011, 06:41 PM
MSFT-1's Avatar
MSFT-1 MSFT-1 is offline
 
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Default Shimmy during landing

My RV-10 with about 580 hours on it has developed a shimmy during landing. After I touch down and begin to slow down, it briefly shimmies at around 25kts during the rollout. I have the stick back to unload the nosewheel but I am braking.

The shimmy lasts for a few seconds and then goes away. It does not happen during taxiing or during the takeoff roll (though I am passing through the same speed range as during the landing rollout).

I looked over the nosegear carefully and found nothing out of whack. Could it have something to do with one of the mains or with the brakes?

If anyone else with a -10 has seen this or has thoughts I would appreciate your comments.

Note: It has around 1000 landings on it and only recently started doing this. The tires are relatively new and in good condition and properly inflated.
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  #2  
Old 11-12-2011, 06:44 PM
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Tire balance?

greg
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  #3  
Old 11-12-2011, 09:21 PM
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That's a pretty common complaint.

Try picking up your nose wheel and moving the gear leg side to side. A lot of times it is the bushing that has worn and allows the nose to have some side-to-side play in it.

I know of a few folks who machined new bushings to custom fit their nose gear. It might even be possible to shim it somehow.

Let us know what you find.
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  #4  
Old 11-13-2011, 08:11 AM
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Matco axle will end the side to side excess play issue.

http://www.matcomfg.com/AXLEASSEMBLY...dv-3657-1.html
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Flying as of 12/4/2010

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"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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  #5  
Old 11-13-2011, 08:50 AM
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I'm talking about the VA-143 bushing. Grab the leg and try to move it, not the wheel. (Though checking the wheel is still a good thing to rule out)

I can post a screenshot of the plans later today if you don't have a copy.
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  #6  
Old 11-13-2011, 09:07 AM
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Default OOPS

Sorry Phil, misread your post.

But, the Matco axle is still a good solution to the problem of the wheel bearing side shims wearing.
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VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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  #7  
Old 11-13-2011, 09:57 AM
aerhed aerhed is offline
 
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Quote:
But, the Matco axle is still a good solution to the problem of the wheel bearing side shims wearing.
Mike, I know there's a lot of thread about this, but why do people think the side shims (spacers?) wear? The factory setup is just like lots of cert planes and they don't often do that. Just looking for opinions as to cause.
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  #8  
Old 11-13-2011, 10:16 AM
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Aerosport1 Aerosport1 is offline
 
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It is most likely your main gear. The wheels pants get into a shimmy and
It is an up and down motion. I have mounted a small camera on the bottom
Of my airplane to see what was happening. It was the main gear and more
My left than right. That being said I have balanced the wheels and that has helped a little bit. My airplane does it a little at 34 KTS ground speed. The more it is loaded the worse it can be. I actually move the speed in which it
Happens to a lower speed by decreasing air pressure. I bet if you remove
Your wheel pants on the Mains and go fly it will be gone. The problem is the
Main landing gears design is not the best for how it is being used. They need
Stiffeners on front and back to help.
I find that I can break through it very quickly so it does not happened. you do not notice it on takeoff because you go through that speed quickly when
Accelerating.

New tires helped a little bit also

FWIW
Geoff
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  #9  
Old 11-13-2011, 10:24 AM
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The particular setup I have personal experience with was an alum spacer, that butted against a wheel bearing with a seal.

The seal had a small amount of the steel "washer" riding on the bearing inner race, which had an inner radius in it.

The total surface area that the spacer contacted the bearing race was less than 1/4 of the thickness of the spacer, and it caused the soft spacer to wear out enough to allow side play.

I have photos of it, but they are a bit out of focus------hazards of a $39 WalMart camera. And, it seems they are no longer on the web, so I guess I could take more photos, and post them if needed. I do believe the parts are still out in the hangar........

This was on an early RV 10 that a buddy built, and it is possible the design has been updated from the factory, but I do not know.
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Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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  #10  
Old 11-13-2011, 11:18 AM
aerhed aerhed is offline
 
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Ah. So the spacers do not make full wall thickness contact with the inner race? I can see that not lasting well I guess.
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