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  #1  
Old 04-16-2021, 03:51 PM
Russ Sly Russ Sly is offline
 
Join Date: Jul 2005
Location: Elk Ridge, Utah
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Default nose wheel shimmy

what is the fix for nose wheel shimmy?
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  #2  
Old 04-16-2021, 04:24 PM
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MacCool MacCool is offline
 
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Location: central Minnesota
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In my experience so far....lower tire pressure and equal main gear pressures. Stick in your belly.
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  #3  
Old 04-16-2021, 04:26 PM
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Be sure the breakout force is correct.

Also, wheel balance and roundness can play a part in shimmy issues.
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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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  #4  
Old 04-16-2021, 04:51 PM
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Quote:
Originally Posted by Mike S View Post
Be sure the breakout force is correct.
What is the correct breakout force, and how do your measure it? Are talking just measuring torque on the castle nut? Does that apply if you have the Anti-Splat Aero bearing mod?
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Last edited by MacCool : 04-16-2021 at 05:03 PM.
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  #5  
Old 04-16-2021, 05:13 PM
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Skid Skid is offline
 
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Quote:
Originally Posted by MacCool View Post
What is the correct breakout force, and how do your measure it? Are talking just measuring torque on the castle nut? Does that apply if you have the Anti-Splat Aero bearing mod?
See drawing below. Make sure the nose wheel is off the ground. Wheel balance and tire pressure are also important some use lower tire pressure, I use 40-45PSI.
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  #6  
Old 04-16-2021, 05:17 PM
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jcarne jcarne is offline
 
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Quote:
Originally Posted by MacCool View Post
Does that apply if you have the Anti-Splat Aero bearing mod?
Yes, the bearing mod just changes the hub from tapered bearings with lots of friction to very nice radial ball bearings with little friction. I have mine set above 25lbs of breakout force. (mine is a -7A but the forks/wheels should all be the same unless it's really old)
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  #7  
Old 04-16-2021, 05:34 PM
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A general FYI suggestion, Amazon sells a cheap hand held digital hook scale, actually marketed for weighing luggage. Makes for a great and accurate (enough) way of measuring the breakout force. I do it at every CI now.
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  #8  
Old 04-16-2021, 06:17 PM
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Mike S Mike S is offline
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Fish scale.
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Mike Starkey
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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  #9  
Old 04-16-2021, 06:49 PM
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Quote:
Originally Posted by sbalmos View Post
A general FYI suggestion, Amazon sells a cheap hand held digital hook scale, actually marketed for weighing luggage. Makes for a great and accurate (enough) way of measuring the breakout force. I do it at every CI now.
My plane has an Anti Splat nose mod. When I bought it home, the nose wheel tire pressure was set at 50 psi by previous owner. I did notice some shimmy, but it went away when I re-set the nose tire pressure to 30 psi.

I ask because I noted just this afternoon that the nose wheel was flat. I replaced the tube, but wasn't sure about the axle torque. It would have been a good time to measure breakout force, but I didn't know how.

So...I get the concept (presumably) of using a fish scale or similar to measure the amount of pressure it takes to rotate the nose gear, but.....how is that done, exactly? Where to you hook the fish scale?
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IFR certified
AFS 5400/3500, G5, 430W, some other stuff
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  #10  
Old 04-16-2021, 06:52 PM
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Mike S Mike S is offline
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Quote:
Originally Posted by MacCool View Post
So...I get the concept (presumably) of using a fish scale or similar to measure the amount of pressure it takes to rotate the nose gear, but.....how is that done, exactly? Where to you hook the fish scale?
Go back to post 5, the wire hook goes into the axle hole.
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Mike Starkey
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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