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In a message dated 4/8/2006 4:37:46 PM Eastern Daylight Time, [EMAIL PROTECTED] writes:
Make sure the bolts on the nutcracker are tight enough to prevent all lateral movement.
I would use some caution when tightening these bolts. These bolts connect two pieces of cast and machined aluminum (with bushings pressed into them for the bolt to pass through). If the aluminum wear surfaces are worn enough to allow lateral play, then in my opinion, this play should be removed using shim stock between the aluminum pieces to take up the clearance. If there is a lot of play there, and you remove it by just tightening the bolt down, then you are bending or squeezing the "ears" of the aluminum castings to take up the clearance. Aluminum castings are not meant to be bent like this. Also, if the "ears" are squeezed together to take up the clearance, then the bores of the holes that the bolt passes through cannot possibly remain in perfect alignment, which will result in premature bushing and bolt wear. If the "ears" are squeezed together then the centerlines of the bolt holes will no longer be aligned. Furthermore, squeezing the ears together like this will just remove the clearance from the portion of the ear that can bend (the end that does not adjoin the rest of the casting), which will cause even faster wear, since the surface that is now making contact is now smaller and concentrated only on one side of the bolt hole.
I agree that there should be little, if any, lateral movement in any of these joints. But distorting the castings to remove the clearance is not the way to go in my opinion.
A couple of other possibilities that might cause nose wheel shimmy:
Worn scissors bushings,
worn scissors bolts,
under-inflated or over-inflated tire,
too much vertical clearance between the steering collar and the nose gear strut,
worn rod end(s) on the nose gear steering pushrod,
worn out or loose nose wheel bearing
As always, check with your licensed mechanic before using any info provided here. I'm not a licensed mechanic, so take this info for what it is worth.
BTW, I went to the South Carolina Breakfast Club Fly-In again this morning, which was at a private airfield. The runway pavement is only about 20 feet wide there, and the departures were with a quartering tailwind, so everyone was watching the take-offs and landings. I saw a Cessna 172 and a Cherokee 180 take-off that both had pretty bad nose gear shimmy during the take-off run! So our planes are not by any means the only ones with nose gear shimmy problems.
Best Regards,
Wayne DelRossi
Alon N5618F
Hours logged since restoration: 121.9
Wayne DelRossi
Alon N5618F
Hours logged since restoration: 121.9
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