T-34C AIRCRAFT SYSTEMS FAMILIARIZATION
Nose Gear Centering Pin
The nose gear centering pin, located on the right side of the nose landing gear shock strut returns
the nose wheel to the center position as it is retracted, allowing the wheel to fit into the wheel
well. It also keeps the nose wheel centered when the shock strut is extended and the aircraft is
airborne to allow for a smoother touchdown upon landing. The centering pin only works when
there is no weight on the nose wheel and the strut is extended.
The shimmy dampener (Figure 19-2) is a small shock absorber located on the left side of the
nose landing gear shock strut that dampens out nose wheel vibrations during takeoff or landing.
Main and Nose Gear Fairing Doors
The main and nose gear fairing doors, which coincide with the gear movement, finalize the
covering of the gear wheel wells when retracted to provide a smooth aerodynamic surface.
When the gear is lowered actuating rods from the landing gear gearbox open the main gear
inboard doors, the main gear extends into place, and the actuating rods close the doors. When
the gear is raised, the reverse occurs. The main gear fairing doors attached to the strut move up
and down with the strut. The nose gear fairing doors consist of a panel attached to the nose gear
strut, and doors on the left and right side of the wheel well. These doors are closed by the
movement of the nose strut itself, and opened by the opposing spring action of a torque tube as
the strut begins to exit the wheel well.
Downlocks are located on both the nose and main landing gears to lock the landing gear in the
extended position and prevent unintended retraction of the gear when the aircraft is on the
ground. The nose gear is held down by mechanical advantage (locking action of gears in
gearbox), and an over center pivot (joining of bottom of V-brace and top of side/drag brace).
The main gear are held down by mechanical advantage, overcenter pivot, and positive
downlocks. When the main gear is down, the lock is held in position by a cable attached to the
main gear inboard door. When retracted, the positive downlock is removed by opposing spring
action. A mechanical downlock is not needed on the nose gear, since it does not experience the
large lateral forces sensed by the main gear on landing.
Uplocks are used to prevent unintended movement of the landing gear out of the wheel well
(landing gear "sag" or "creep"). The nose and main gear are held in the retracted position by
mechanical advantage and a positive uplock. On the main gear the positive uplock is held in
position by a cable attached to the main landing gear inboard door and removed by opposing
spring action. On the nose gear the uplock consists of an uplock receptacle (hole in an aft facing
metal tab) at the bottom of the shock strut and a torque tube operated by the landing gear
LANDING GEAR SYSTEMS 19-5