What is landing gear shimmy?
Shimmy vibration is a common phenomenon in landing gear systems during either the take-off or landing of aircrafts. It is the state of self-excite oscillations in lateral and torsional directions caused by the interaction between the tires and the runway. The damage of the landing gear can also lead to accidents.
What happens if a plane’s landing gear doesn’t come down?
In cases where only one landing gear leg fails to extend, the pilot may choose to retract all the gear and perform a belly landing because he or she may believe it to be easier to control the aircraft during rollout with no gear at all than with one gear missing.
What happens if you retract landing gear on the ground?
Sometimes pilots may retract landing gear a little early when they are taking off. As soon as the plane is lifting itself from the ground and the landing gear gets extended, they can move the lever and wheels go in. However, at this point nothing serious can happen, since the plane is already taking off anyway.
What is nose wheel shimmy?
A nosewheel shimmy is a rapid back-and-forth oscillation of the steerable part of the nosegear and wheel. It can be caused by a variety of problems, and it sometimes takes more than one trip to the shop to get the issue resolved. The nosegear has several points at which it pivots and rotates.
What is a shimmy damper?
The shimmy damper is a hydraulic fluid-filled cylinder that prevents rapid movement of the nose or main landing gear without interfering with slower operations.
Can a helicopter land without landing gear?
No, the helicopter cannot land. The pilot will most likely not be able to maintain safe emergency landing areas on approach & departure.
What is non absorbing landing gear?
[Figure 13-13] The most common example of this type of non-shock absorbing landing gear are the thousands of single-engine Cessna aircraft that use it. Non-shock absorbing struts made from steel, aluminum, or composite material transfer the impact forces of landing to the airframe at a non-damaging rate.
How does a shimmy damper work?
The piston inside the shimmy damper cylinder is designed to move freely back and forth when it is moved slowly enough to allow fluid to transfer from one side of the piston to the other through a restrictor. The slow movement of the piston allows the wheels to pivot so the aircraft can be steered on the ground.
How do you fix a shimmy nose wheel?
When you move the nose wheel right and then left, the shimmy damper should also move. If there is any un-dampered motion, tighten or replace the worn components (i.e. torque link bushings and spacers, the steering collar, and shimmy damper attachments). Next, remove the shimmy damper attachments.