T-34C AIRCRAFT SYSTEMS FAMILIARIZATION WORKBOOK
A compressor bleed valve, located in the compressor section at the 7 o'clock position,
automatically opens a port to spill interstage compressor air to provide anti-stall characteristics.
The combustion chamber is an annular, reverse flow type. Fuel is sprayed into the combustion
chamber by fourteen nozzles and combined with air from the diffuser to form a combustible
mixture. During engine start, the mixture is ignited by two igniter plugs. Thereafter, ignition is
self-sustaining as long as the proper fuel-air ratio is supplied. The process changes a high-
pressure gas to a high velocity gas which is delivered to the turbine section.
The turbine section consists of two, independently shafted, single-stage turbines that change high
velocity gas flow to rotating mechanical energy. The compressor turbine (also called the N1
turbine) rotates counterclockwise, rotating the axial and centrifugal compressors and driving the
turbine will be rotating at 37,000 RPM. The power turbine (also called the Nf turbine) rotates
the propeller set at maximum RPM, the power turbine will be rotating at 33,000 RPM. Between
the two turbine wheels are eight temperature-sensing probes called thermocouples which provide
an indication of interstage-turbine temperature (ITT).
After passing through the power turbine, the expanding gases are discharged, via the exhaust
duct, to the outside atmosphere through two exhaust stacks (also called exhaust nozzles). One is
located on each side of the engine compartment.
The accessory gearbox, located at the rear of the engine, provides the mount and drives for
engine-driven accessories. This gearbox is driven by the compressor turbine shaft.
2-4 BASIC ENGINE CONSTRUCTION