joepilotmooney Posted November 14 Report Posted November 14 20 years I've flown our J model and never felt an intermittent nose gear shimmy during taxi, like what an old Cessna does when I was a low time pilot! Anyone ever experience this? I thought I had a flat nose gear tire. I taxied back to the hangar instead of taking off and everything looked ok...thoughts??
N201MKTurbo Posted November 14 Report Posted November 14 I have had that happen. It happens when your nose gear is warn out. What I do to fix it is to install the LASAR oversized bushing. I’m not sure it is still available. Then I would tighten up the steering horn with shims. I had to make the shims BTW. 2
joepilotmooney Posted November 14 Author Report Posted November 14 Thanks Rich. Do you feel it is airworthy flying with it like that, it seems not to me...?
Shadrach Posted November 14 Report Posted November 14 11 hours ago, joepilotmooney said: 20 years I've flown our J model and never felt an intermittent nose gear shimmy during taxi, like what an old Cessna does when I was a low time pilot! Anyone ever experience this? I thought I had a flat nose gear tire. I taxied back to the hangar instead of taking off and everything looked ok...thoughts?? It's can be caused by a combination of things. Wear in the linkage for sure can cause a shimmy, but low tire pressure can also have an effect. If your linkage is worn or if the caster is slightly out of spec, it will be even more sensitive to tire pressure. 1
N201MKTurbo Posted November 15 Report Posted November 15 6 hours ago, joepilotmooney said: Thanks Rich. Do you feel it is airworthy flying with it like that, it seems not to me...? I flew my old M20F like that for 100 hours or so. I ferried a Mooney about 2 years ago that did it. It took it 40 years or so to get the way it is, it will stay about the same way for a long time. You should plan on fixing it, but in the mean time, if you kick the rudder pretty hard, it will usually stop the shimmy. 3
Nico1 Posted November 15 Report Posted November 15 Also, make sure steering horn is packed with grease, that helps a lot. 1
Fritz1 Posted November 15 Report Posted November 15 simplest way to raise nose if no jack available is engine hoist on engine, then move nose wheel and see what wobbles, there is vertical #10 bolt in the idler bushing in the linkage on the right side of the wheel well, make sure lock nut on bottom is tight, eventually replaced that bolt and drilled that bolt for a cotter pin and used a castellation nut since new lock nut keep getting loose, think the steering horn washers come only in two or three sizes, best way to really get it tight is to have a standard washer machined down, next comes replacing the Heim joints if they are worn
Hank Posted November 15 Report Posted November 15 2 hours ago, Fritz1 said: simplest way to raise nose if no jack available is engine hoist on engine, I've stacked oil on the horizontal stab, then my wrench roll and several bound approach plate booklets. Keep adding stuff until the nose gets very light, then have a helper push down on the tail and hold it in position. This works only for short periods.
Beard Posted November 16 Report Posted November 16 I installed the LASAR oversized bushing and adjusted some linkages. I have a friend with an RV7 who played around with different nose wheel air pressures that cured his wobble.
Mufflerbearing Posted Wednesday at 06:29 PM Report Posted Wednesday at 06:29 PM Be sure to check the castor. There is quite a bit on Mooneyspace that talks about the procedure with diagrams. It's really simple to check and helps to narrow down what is going on. There is a collar for the shock discs that has an offset hole drilled for the retaining bolt. Sometimes this collar is installed upside down with the shorter side installed toward the bottom. This changes the castor significantly enough that several planes have been wrecked because the mechanic changing the shock discs installed it upside down. This makes the plane feel squirrelly when taxiing or take off but especially so when landing.
cliffy Posted Thursday at 03:01 AM Report Posted Thursday at 03:01 AM No wouldn't continue flying it until you research what could be wrong. The forces on the nose gear are tremendous when it is shimmying You will have to taxi it to check out any repairs however, The big pivot bolt is torqued to 300 in pounds and secured with a cotter pin (280-300) Make sure it is lubed completely I caution loading the stab with heavy weights Its not stressed for that and could deform in airfoil. Most likely your linkage above the nose wheel for steering is worn and needs attention. Get the nose in the air and turn the wheel left and right . If its real loose more than a few degrees it needs fixing. First order is to check tire pressure for correct PSI If low fill it and do a taxi test That may be all you need If however your steering linkage above the gear has not been looked at in decades that will probably be where the issues emanate If it has been a sudden onset of shimmy it probably is not the CASTER angle..
Mufflerbearing Posted Friday at 12:45 AM Report Posted Friday at 12:45 AM 21 hours ago, cliffy said: If it has been a sudden onset of shimmy it probably is not the CASTER angle.. Well, this is not exactly true. Not only was my collar installed upside down (prior to me purchasing the plane), but that collar broke which caused an immediate caster angle change to 1.75". Well over an inch past maximum allowed.
cliffy Posted Friday at 02:52 AM Report Posted Friday at 02:52 AM Well that puts it into an entirely different light.
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