SOLAR T62 AUXILIARY POWER UNIT
The SOLAR T62 auxiliary power unit (APU) is used in place of ground support equipment to
start some helicopter engines. It is also used to operate the helicopter hydraulic and electrical systems
when this aircraft is on the ground, to check their performance. The T62 is a component of both the
CH-47 and CH-54 helicopters -- part of them, not separate like the ground-support-equipment APU's.
On the CH-54, the component is called the auxiliary powerplant rather than the auxiliary power unit, as
it is on the CH-47. The two T62's differ slightly.
This chapter describes the T62 APU; explains its operation; discusses the reduction drive,
accessory drive, combustion, and turbine assemblies; and describes the fuel, lubrication, and electrical
The T62 gas turbine engine auxiliary unit consists of a combustor, turbine, reduction drive
and accessory drive assemblies, engine accessories, plumbing, and wiring. The engine has a single shaft
with the compressor and turbine rotor mounted back-to-back.
The T62 develops approximately 70 shaft horsepower. It has its own fuel control unit,
hydraulic starter motor, ignition unit, and reduction gear drive. Operating time for the APU is
maintained separately from aircraft engine time by an hour meter mounted on the APU. The T62 used
on the CH-47 differs slightly from the one used on the CH-54. The accompanying table IV gives the
particulars for each engine.
Both models of the T62 are shown in figures 6.1 and 6.2.
THEORY OF OPERATION
The T62 gas turbine engine consists of three major sections: the reduction and accessory
drives, the combustor, and the turbine sections as shown in figures 6.1 and 6.2. Air is drawn into the
inlet of the engine when the hydraulic starter rotates the compressor during the starting cycle. After the
engine is started, air continues