AIRCRAFT SYSTEMS LANDING GEAR Flashcards
To provide a means of maneuvering
the aircraft on the ground.
To support the aircraft at a convenient
height to give clearance for propellers
and to facilitate loading.
To absorb the kinetic energy of landing
and provide a means of controlling
deceleration.
Functions of the landing gear
2 Landing Gear Layouts
Tricycle, Tailwheel
With slow, light aircraft, and some larger
aircraft on which simplicity is of prime
importance, a ___________ is often fitted.
fixed (non retractable) landing
gear
With higher performance aircraft, drag
becomes progressively more important, and a
___________ is retracted into the
wings or fuselage during flight.
retractable landing gear
3 Main Types of Fixed Landing Gear
Spring Steel Leg
Rubber Cord (Shock Absorber)
Oleo-Pneumatic Struts
These are usually
employed at the main
undercarriage positions. The leg
consists of a tube, or strip of
tapered spring steel. The upper
end being attached by bolts to the
fuselage and the lower end
terminating in an axle on which
the wheel and brake are
assembled.
Spring steel legs
When ___________ is used as a
shock-absorber, the
undercarriage is usually in the
form of tubular struts, designed
and installed so that the landing
force is directed against a
number of turns of rubber in the
form of a grommet or loop.
rubber cord
Some fixed main undercarriages, and
most fixed nose undercarriages, are
fitted with an _____________ shock
absorber strut. The design of individual
struts varies considerably but the
operating principle is same for all.
Additionally, one point worthy of
consideration is the fitting of spats to
___________ strut.
oleo-pneumatic
These are an aerodynamic fairing
which may be required to minimize the
drag of the landing gear structure.
Spats
A _____________ consists of two
concentric cylinders, one free to slide inside the
other.
simple oleo-pneumatic strut
The cylinders are filled with hydraulic fluid and gas.
Fluid and gas are kept apart by a_________.
separator piston
The outer or upper cylinder is attached to the
___________. It houses the inner or lower
cylinder and a piston assembly.
airframe structure
The ___________ are connected to the bottom of
the inner cylinder.
wheels and axle
The inner cylinder is free to rotate and move up and
down within the outer cylinder. Rotary movement
and up and down movement is limited by the
__________ which connect the inner and outer
cylinders together.
torque links / torsion / scissor links
Landing gear is subject to_______
during ground maneuvering and these
loads are taken by the torque links.
torsion loads
The smaller the radius of turn, the
_______ will be the load felt by the
torque links so all turns should be
made as _____ as possible.
greater ; wide
The area on the outer cylinder is filled with
_____________ and the area on the inner
cylinder is filled with __________ which
may be air or nitrogen.
hydraulic fluid ; compressed gas
__________ is a free-floating piston which
keeps the fluid and gas apart.
Separator piston
The purpose of the hydraulic fluid is to ________________________________.
dampen oscillations and
control the rate of compression and extension of the cylinders
There is a component known as a _________
which is fitted to the lower cylinder piston
assembly. The _________ consists of a
free-floating circular plate with a large central hole.
It is free to move up and down within its housing.
flutter valve
the gas pressure will support the weight of the aircraft with the lower
cylinder approximately on the midway of its stroke.
Aircraft Stationary on the ground
cushioned by the gas
pressure and dampened by the limited flow of fluid
through the orifice.
Bumps during taxiing
gas pressure will cause the lower part of
the leg to extend to its fullest extent.
Takeoff
