Compressor - The compressor assembly
consists of a compressor front support, shroud housing,
diffuser, rear support assembly, centrifugal impeller,
scroll assembly, mount assembly and bearings. The front
support encloses the front bearing and supports it through
five hollow inlet struts. The struts are hollow to permit
anti-icing using compressor discharge air; also, to permit
introduction of oil to and from the compressor front
bearing. The compressor rear bearing is mounted in the rear
support assembly and is lubricated from the gearbox.
Combustion Section - The combustion section consists of an
outer combustion case and a combustion liner. The
combustion liner is located in the outer combustion case.
The liner is supported and oriented at the forward end by
the gas producer turbine first stage nozzle vane assembly
and at the rear by the fuel nozzle. The fuel nozzle is
mounted in the aft end of the outer combustion case. The
igniter plug is mounted near the aft end of the case. Air
enters the single combustion liner at the aft end through
holes in the liner dome and skin. The air is mixed with
fuel sprayed from the fuel injector and combustion takes
place. Combustion gases move forward out of the combustion
liner to the first-stage gas producer turbine nozzle.
Turbine - The turbine consists of a gas producer turbine
support, a power turbine support, a gas producer turbine
rotor, a power turbine rotor and a turbine and exhaust
collector support. The turbine is mounted between the
combustion section and the power and accessory gearbox. The
two-stage gas producer turbine drives the compressor and
accessory gear train. The two-stage power turbine drives
the spare pad, Permanent Magnet Alternator (PMA) pad and
furnishes the output power of the engine. The expanded gas
discharges in an upward direction through the turbine and
exhaust collector support. The rear engine mount is located
on the bottom rear of the turbine.
Power and Accessory Gearbox - The main power and accessory
drive gear trains are enclosed in a single gear case. The
gear case servers as the structural support of the engine.
All engine components including the engine-mounted
accessories are attached to the case. A two-stage helical
and spur gear set is used to reduce rotational speed from
30,650 rpm at the power turbine to 6016 rpm at the output
drive spline.
The gas producer gear train drives the compressor,
hydromechanical unit (HMU), the pressure and scavenge oil
pump (inside the gearbox), and a pad for an optional
airframe furnished gas producer tachometer-generator. In
addition to providing output power of the engine, the power
turbine gear train drives the permanent magnet alternator
(PMA), a pad for an optional airframe furnished power
turbine tachometer-generator, and a spare pad on the rear
of the gearbox. The gearbox also contains two engine
furnished dual winding monopole pickups. One of the pickups
is used to measure gas producer speed; the other is used to
measure power turbine speed. On each pick-up, both coils
provide an input signal to the ECU, and one of the signals
is shared with the airframe.
Fuel System - The HMU (Hydromechanical
Unit), Low Pressure Fuel Filter, and Fuel Nozzle are the
major fuel system components.
Control System - A Full Authority Digital Electronic
Control (FADEC) system is installed on the 250-C30R/3
engine. The FADEC is a single channel control, with a
hydromechanical back-up (manual mode). It has engine
torque, temperature and speed limiting capability. The
FADEC system has two main components. The Electronic
Control Unit (ECU) is airframe mounted. The ECU monitors,
controls and limits engine speed, fuel flow, acceleration
rate, temperature, torque and other engine parameters. An
engine-mounted Permanent Magnet Alternator (PMA) provides
all required electrical power to the ECU a power turbine
speeds of 85% and above. The second FADEC component is the
Hydromechanical Unit (HMU). The HMU is engine mounted and
driven by the N1 gear train. The HMU includes the fuel
metering unit and both a boost stage (high performance
liquid ring) fuel pump and main fuel pump (gear stage). A
fuel filter is located between the boost and main pump
stages. In manual mode, the HMU provides altitude biased
and slew rate limited fuel flow as a function of power
level angle.
Lubrication System - The lubrication system is a
circulating dry sump type with an external reservoir and
heat exchanger mounted and furnished by the airframe
manufacturer. A gear-type pressure and scavenge pump
assembly is mounted within the gearbox.
Ignition System - The ignition system consists of a
harness, a solid-state, low tension, capacitor discharge
ignition exciter, a spark igniter lead, and a shunted
surface-gap spark igniter. The system derives its input
power from an airframe furnished 14-29 Vdc power source.
The ignition system transfers energy to the combustible
fuel mixture. Energy is provided in the form of high
temperature-high voltage arcs at the spark igniter gaps.
These arcs ignite the fuel mixture.
Temperature Measurement System - The temperature
measurement system consists of four chromel-alumel single
junction thermocouples in the gas producer turbine outlet
and an associated integral harness. The voltages of the
four thermocouples are electrically averaged in the
assembly. the harness terminates at a junction block on the
aft side of the horizontal fireshield. The engine
electrical harness and the aircraft indicator harness
connect to this junction box.
Anti-icing system - The compressor inlet guide vanes and
front bearing support hub are the only engine components
with anti-icing provisions. Anti-icing is provided by the
use of compressor discharge air which is taken through a
valve on the compressor scroll. The air shut-off valve is
solenoid controlled and is designated to fail to the "ON"
position (energized "OFF").
250-C30R/3 Engine Ratings
Design power output (Takeoff) 650 shp (485 kW)
Design speeds:
Gas producer (N1) 100% (51,000 rpm)
Power turbine (N2) 100% (30,650 rpm)
Power output shaft 6,016 rpm
Dimensions
Length 43.198 in. (1,097 mm)
Height 25.130 in. (653 mm)
Width 21.996 in. (559 mm)
Max. Engine Weight (dry) 274 lb (124 kg)
Max. Oil Consumption Appx. 1qt/5hr (0.05 gal/hr-0.19
l/hr)