TM 1-1500-204-23-2
Figure 4-175. Liquid Spring
2 Core removal. Valve cores shall not be
removed from valve body unless it will be replaced with
a new core, nor will it be removed or loosened from
hydraulic accumulators or shock struts to exhaust pres-
sure and then be reinstalled (figure 4-174).
NOTE
In case a core is reinstalled, it shall be
seated tightly and examined for leaks.
3 Core installation. Valve cores shall not
be reinstalled when removed from hydraulic pressure
accumulators or shock struts, except when cores of
proper type are not available or when aircraft involved
is needed for tactical or other urgent use.
4 Core cap. Install a low temperature
valve core cap, part No. MS20813. These caps are
painted yellow for identification as low temperature
caps.
c. Liquid Springs. The liquid spring contains
hydraulic fluid under pressure. The cushioning effect of
the spring is produced by effecting a slight compression
in the fluid. Note in figure 4-175 that the piston rod fits
into the inner space of the cylinder and that a gland seal
is provided to prevent fluid leakage as the piston rod
moves into and out of the housing. The housing is
attached to a stationary part of the aircraft, and the
piston rod is connected to a movable part of the landing
gear. A typical installation of a liquid spring on a tail
landing gear of an Army aircraft is shown in figure 4-176.
(1) Uses. The liquid spring performs the same
functions as the shock struts just discussed, but there
are differences in operation. The manner in which the
liquid spring performs these functions is described in the
following paragraphs.
(a) Supporting static loads. The weight of
the parked aircraft tends to move the housing of the
liquid spring downward over the piston rod. The inward
movement of the piston rod decreases the space
occupied by the fluid. This compresses the fluid, thus
increasing Its pressure. The movement continues until
fluid pressure puts a force on the shaft equal to the force
tending to move the shaft inward. When this point is
reached, no further Inward movement of the shaft takes
place and the aircraft is held In a stationary position.
Figure 4-176. Tailwheel Liquid Spring
4-165
