Mark L's response to my comment, and my expansion on my earlier remarks. >Mark W wrote:
>> If the caster angle and wheel & tire balance are right, you shouldn't have >> this problem... think GM/Ford/Chrysler front end alignment... not shopping >> cart. I've yet to see a Corvette experience 'shimmy' at speeds exceeding >> anything a KR would land at. >Mark L wrote: >I would have to disagree with that. You can have a perfectly balanced >wheel/tire, but external forces such as which way the wheel is pointed at >touchdown, or even which way the wind is blowing, can get the shimmy >started. That's a side to side phenomenon, ...... >Mark Langford > Maybe I should have emphasized caster angle a little more... caster angle (the angle from the vertical pivot point to the contact patch of the tire on the pavement, similar to the trail on a motorcycle) can improve the stability and natural tendency of the tire to track true. I agree with all of the points that Mark L has made, but the video I saw showed the shimmy continuing all the way down the runway... if the caster angle and balance had been properly done, the shimmy would tend to cancel out as the plane went down the runway. Granted, I know more about motorcycles and cars than I do about planes, but once the bird is on the ground, I would think similar rules would apply. Yes damping is important, but if the geometry of the set-up is off, it won't help the shimmy unless the gear is "locked in" (too stiff) which kind of defeats the purpose of a castering nose wheel doesn't it? JMHO Mark W N952MW
