b. Oil scavenge system. All internal scavenge oil from the
inlet housing section drains through a hollow support strut to the
bottom of the inlet housing through a scavenge strainer and transfer
tube, and into the accessory drive gearbox. Scavenge oil from the
output reduction carrier and gear assembly flows by gravity into the
hollow inlet housing struts.
Scavenge oil from the No. 1 main bearing is pumped to the
inlet housing struts by an impeller or paddle pump located on the
rear of the bearing. Scavenge oil from the No. 2 main bearing flows
through a scavenge oil tube, illustrated at G in figure 4.31B, in the
diffuser housing and is directed to the accessory drive gearbox by an
external scavenge oil hose assembly. Scavenge oil from the No. 3 and
4 bearings, as shown in figure 4.31B(F), flows through an oil tube
that extends through the bottom of the exhaust diffuser and is
directed to the accessory drive gearbox by an external oil scavenge
hose assembly. The scavenge portion of the powerdriven rotary oil
pump returns scavenge oil from the accessory drive gearbox through
the aircraft oil cooler to the aircraft oil storage tank.
4.21.
TORQUEMETER SYSTEM
The torquemeter shown in figure 4.32 is used on the T53L13;
it is a hydromechanical torquemeasuring device located in the
reductiongear section of the inlet housing. It uses boosted engine
oil to measure engine torque effort; the measurement is read in the
cockpit as torque oil pressure in psi. Although this system uses
engine oil, it is not a part of the lubrication system. The
following numbers in parentheses correspond to the numbers in figure
4.32.
The mechanical portion of the torquemeter consists of two
circular plates. One is attached to the inlet housing and is
identified as the stationary plate (1). The second, or movable plate
(2) is attached to the reduction gear assembly (6). The movable
plate contains front and rear torquemeter sealing rings (12), which
enable it to function as a piston in the rigidly mounted cylinder
(3). The cylinder assembly houses the variableopening torquemeter
(poppet) valve (4). The movable plate maintains the fixedorifice
metered bleed (13), which functions in relation with the poppet
valve. The movable plate is separated from the stationary plate by
steel balls (5) positioned in matched conical sockets machined in the
surfaces of both plates. When the engine is not operating, the
torquemeter movable plate is a position forward and clear of the
torquemeter valve plunger, allowing the springloaded valve to remain
in the closed position. With the engine operating and a load applied
to the output shaft (14), the torque
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