Nose wheel

flightexpress

flightexpress
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phantom ultralight bensen
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I was going to fly my Don the other night. Did a preflight and taxied out to the runway. As I started to go down the runway at a good speed the nose wheel was all over it almost did a 180 I thought it would break off. Does anyone know what is going on. At slow taxie it works fine but as soon as you start going fast the nose wheel is all over.

Thanks
 

Doug Riley

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Jan 11, 2004
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If by "all over" you mean shimmy, yes, it can happen and can be pretty violent. There's an adjustable friction-damping collar near the top of the nose-dear leg. Tighten it until there's noticeable drag when you swivel the gear with your hands -- but not so much that it won't turn when you apply the steering brakes. There's a trouble-free sweet spot.

If your problem is not shimmy but uncommanded random turns, could a brake be grabbing periodically, perhaps from some looseness or warping?
 

flightexpress

flightexpress
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phantom ultralight bensen
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Yes Doug I could think of the word but shimmy is the best word to describe it. Do you put the collar up or down on the nose gear. It looks like it's in the middle. Do those collars go bad.

Thanks
 

j bird

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Doug, could the bearing on the fork be loose?
 

Doug Riley

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JBird, it's possible that the gear's pivot might develop enough slop to contribute to shimmy. It seems less likely to me than a lack of friction in the collar, though.

Flight Express, the friction collar is an aluminum block, with a big hole through which the gear leg passes. The block is split. The split can be opened or closed slightly by tightening or loosening a bolt. Inside the big hole in the collar is a soft plastic sleeve or liner. If this is worn (or missing) then, yes, the friction won't work as intended.

The collar is prevented from rotating with the gear leg by a vertical bolt that is secured into the base of the gear leg assembly, up at the keel. This bolt fixes the collar's position up/down on the leg, so i don;'t see how the collar could be anywhere lower than it's supposed to be (well, unless that anti-rotation bolt is unscrewed or gone). Shoot us a pic and we might be able to diagnose the problem more accurately.
 

flightexpress

flightexpress
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MN
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phantom ultralight bensen
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No Title

Ok thanks guys I see my problem. I went out tonight and saw that I'm missing the front bolt. It looked like it sheared off
 

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gyromike

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Abbeville, Louisiana
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That would do it.
This would be a good time to take the nosewheel assembly off and inspect/clean/lube the headstock bearings, and also take a measurement of the O.D. of the fork tube and the I.D. of the damper and replace the Teflon strip. It looks a little beat up.
The spacer that holds the damper in place can be made from a piece of aluminum solid rod with a 1/4" hole in it. I don't recall the dimensions right off.
Or you could that stuff from Ernie.
 

flightexpress

flightexpress
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MN
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phantom ultralight bensen
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Any idea what would be to get that broken bolt out.
 
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