Figure 12-20.--Fluid flow.
Before installing a pump, the pump and its
PISTON-TYPE
PUMP
(VICKERS
attached hose assemblies must be primed (filled with
E L E C T R I C M OT O R - D R I V E N VA R I A B L E
fluid). During installation, the pump must be
DISPLACEMENT).--This type of pump is used in
s o m e o f t h e N a v y 's m o s t m o d e r n a i r c r a f t .
continuously supported with its shaft parallel to the
Motor-driven variable displacement pumps have
mounting studs, and the splines must mesh with the
several advantages over the engine-driven models.
driving element.
Some of these advantages are as follows:
If the pump drive shaft does not engage the driving
1. Ease of installation and removal due to the
element, preventing the pump from sliding into place,
accessibility of the component.
the drive shaft should be manually rotated until the two
splined drive shafts mate.
2. Constant speed of the drive shaft.
12-18