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High Speed Main Gear Shimmy
Posted: Thu Feb 02, 2023 6:17 am
by tdragger
My plane has a considerable shimmy starting at ~55mph while up on the mains. Same thing on a wheel landing up on the mains, shakes like a dog with fleas until the speed bleeds below ~55 mph. It's not a new issue but one I want to correct.
Q- Will improper gear alignment cause this? I checked the gear attachment bolts and they are fine. The pilot side tire shows minor wear on inboard side of the tread
If its an alignment issue wouldn't the issue show its head at the lower speeds as well?
Thanks for any input.
Re: High Speed Main Gear Shimmy
Posted: Thu Feb 02, 2023 2:55 pm
by 2066
A bit of guessing, but it smacks of an alignment issue to me, possibly combined with an out of balance (tire) that presents with the speed(?). It sounds like you've already checked for anything gear-related being "loose". I'd prob check alignment first but also look at tires to be sure they're mounted properly ("Some aircraft tubes feature balance marks to indicate the heavy portion of the tube. These marks are approximately 1/2" wide and 2" long. When inserting the tube in the tire, its balance mark should be aligned with the balance mark on the tire. If the tube has no balance mark, align the valve with the balance mark on the tire.")
Mac
Re: High Speed Main Gear Shimmy
Posted: Thu Feb 02, 2023 9:48 pm
by 6597
My 2-bits....
I bought some AirTracs moons ago and they turned out to be the most off balance tires, I have a bunch of lead tape in the wheels to try to help.
May want to check your bearings, when I switched to Grove axles I found they had extra holes for the cotter pins so I could get a finer tightening on the bearings/less play.
I also got rid of my extenders as they contributed a fair amount of shimmy.
And yes, do check alignment.