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Shimmy effect on LG
- Thread starter luca28
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have you tried to research this on your own ?
a quick google for "landing gear shimmy" found lots of hits, including one with ...
"Shimmy is an oscillation in aircraft landing gear that can occur both on landing and take-off, typically in a band of velocities. It causes excessive wear on components and can cause accidents. The nose wheel is roughly like a caster on a shopping trolley: the horizontal axle of the wheel is mounted in an assembly that is free to rotate about a vertical axis. Shimmy is (or at least includes) oscillation of the wheel assembly about this vertical axis. The current engineering approach has little understanding of the physical mechanisms causing shimmy, but relies on the use of shimmy dampers, and on systematic maintenance and replacement of landing gear components."
hope that helps your assignment ...
a quick google for "landing gear shimmy" found lots of hits, including one with ...
"Shimmy is an oscillation in aircraft landing gear that can occur both on landing and take-off, typically in a band of velocities. It causes excessive wear on components and can cause accidents. The nose wheel is roughly like a caster on a shopping trolley: the horizontal axle of the wheel is mounted in an assembly that is free to rotate about a vertical axis. Shimmy is (or at least includes) oscillation of the wheel assembly about this vertical axis. The current engineering approach has little understanding of the physical mechanisms causing shimmy, but relies on the use of shimmy dampers, and on systematic maintenance and replacement of landing gear components."
hope that helps your assignment ...
Februarys Maintenance alerts, pages 14 t0 17 has a rather dramatic picture of what can, happen, if you do not get all of the parameters correct, or if you overlook a pilot action you did not think they would do. In this case a landing gear oscillation caused by stomping too hard on the brakes.
B.E.
B.E.
- Thread starter
- #5
MiketheEngineer
Structural
My last landing... Unbeknown to us - the nose weheel had fallen off.
THAT was one hell of shimmy!!
THAT was one hell of shimmy!!
GregLocock
Automotive
"The current engineering approach has little understanding of the physical mechanisms causing shimmy"
Is that true? Or is just somebody expressing their own ignorance?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
Is that true? Or is just somebody expressing their own ignorance?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
My experience with nose wheel shimmy is that it can be set off by dynamic imbalance of the wheel.
The wheel may easily be statically balanced but dynamic balancing is more difficult to achieve. The average nose wheel won't fit an automotive wheel balancer.
The wheel may easily be statically balanced but dynamic balancing is more difficult to achieve. The average nose wheel won't fit an automotive wheel balancer.
I'd guess there is more to the story than is shown in those Maint Alert photos. Speaking from my own experience as a low time pilot, nose wheel shimmy is very common. The remedy is usually pull the yoke back and keep the weight off the nose until you have slowed down to taxi speed.
It doesen't seem to be a factor much on takeoff.
In those photos, it looks like the pilot was running out of runway and braking hard. He may have just touched down too far down the runway or not had good control of his airspeed.
Sometimes, just going around and not trying to salvage a poorly executed approach can save a lot of money.
It doesen't seem to be a factor much on takeoff.
In those photos, it looks like the pilot was running out of runway and braking hard. He may have just touched down too far down the runway or not had good control of his airspeed.
Sometimes, just going around and not trying to salvage a poorly executed approach can save a lot of money.
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