Ch 2 Systems and Equipment
Ch 3 Aircraft Serving
Ch 4 Aircraft Operating Limitations
Ch 1 General Description
1.1 THE AIRCRAFT
1.1.1 Accommodations
1.1.2 Propulsion
1.1.3 Aircraft Dimensions
1.1.4 Crew Stations
Ch 2 Systems and Equipment
2.1 ENGINES
2.2.1 Power Section
2.1.2 Extension Shaft Assembly
2.1.3 Reduction Gear Assembly
2.1.4 Engine Fuel and Control System
2.1.5 Starting System
2.1.6 Ignition System
2.1.7 Engine Controls and Control Systems
2.1.8 Engine Instuments
2.2
1.1 The Aircraft
The Lockheed C-130 is a high-wing, all-metal, long-range, land-based monoplane. The mission
this aircraft is to provide rapid transportation of personnel or cargo for delivery by parachute
or landing. The aircraft can be used as tactical transports and can be converted readily for
ambulance or aerial delivery missions. The aircraft can land and take off on short runways and
can be used on landing strips.
1.1.1 Accommodations
Ground troops 78.
1.1.2 Propulsion
Power is supplied by four Allison T56-A-16, turboprop, constant-speed engines. There are
provisions for externally mounted ATO to provide additional thrust for takeoff. Each engine
drives a four-blade Hamilton Standard Hydromatic, constant-speed propeller with full feather
and reversible pitch.
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1.1.3 Aircraft Dimension
Slip over
1.1.4 Crew Stations
Crew stations are provided for a pilot, copilot, flight engineer, and/or second flight engineer.
The loadmasterand second loadmaster should use passenger seats located in the cargo
compartment.
2. Flight engineer seat
3. Navigator stowage cabinet
4. Navigator seat
5. Window curtains
6. Booster hydraulic system reservoir
7. Observer control panel
8. Paratroop door
9. Observer seat
13. APU oil reservoir
14. Utility hydraulic system reservoir
15. APU
16. Airborne ladder
17. Engine air intake shields
18. Crew entrance door
19. Galley
20. External power receptacles
21. Battery compartment
22. External interphone connection
11. Water bottles
12. Engine tailpipe shield
2. Altitude Alerter
3. Engine Instrument Pnel
4. Copilot Instrument Panel
2.1 Engines
The aircraft is powered by four Allison T56-A-16 turboprop engines. the basic engine consists of
two major assemblies, a power section, and a reduction gear assembly, which are attached to
each other by an extension shaft assembly and two supporting struts. The engine is provided
with fuel, oil, starting, ignition, and control systems. The engine operates at constant speed;
therefore, engine power is related to TIT, which varies according to the rate of fuel flow. An
increase in fuel flow causes an increase in TIT and a corresponding increase in energy
available at the turbine. The turbine than absorbs more energy and transmits it to the propeller
in the form of torque. In order to absorb the increase torque, the propeller increases blade angle
to maintain constant engine rpm. A decrease in torque results in a decrease in propeller blade
angle to maintain engine speed. Thrust is obtained from the propeller, and a small amount of
additional thrust is created by the tailpipe exhaust.
2.1.1 Power Section
The power section of the engine is composed of a single-entry, 14-stage, axial-flow,
compressor, a set of six combustion chambers of the through-flow type;and a 4-stage turbine.
Mounted on the power section are an accessories drive assembly and components of the
engine fuel, ignition, and control system. Acceleration bleed valves are installed at the 5th and
10th compressor stages. A manifold is installed at the diffuser to bleed air from the compressor
for aircraft pneumatic systems. Anti-icing systems are provided to prevent accumulation of ice in
the engine inlet air duct and the oil cooler scoop. Inlet air enters the compressor through a scoop
and duct below the compressor and is progressively compressed through the 14 stages of
compression. The compressed air ( at approximately 125 psi and 600 degrees Fahrenheit )
flows through the diffuser into the combustion section. Fuel is introduced into the combustion
chambers and burned to increase the temperature and, thereby, the energy of the gases. The
gases pass through the turbine causing it to rotate and drive the compressor, the propeller,
and accessories. The gases, after expanding, through the turbine, flow out through a tailpipe.
2.1.2 Extension Shaft Assembly
The extension shaft assembly consists of two concentric shafts and torquemeter components.
The inner shaft transmit power from the power section to the reduction gear. The outer shaft
serves as a reference so that the torsional deflection of the loaded inner shaft can be detected
by the magnetic pickups of the torque indicating system. Torquemeter amplifier are provided
with adjustment screws for calibration purpose.
2.1.3 Reduction Gear Assembly
The reduction gear assembly contains a reduction gear train, a propeller brake, a NTS system,
and a safety coupling. Mounted on the accessory drive pads are the engine starter,
an ac generator, a hydraulic pump, an oil pump, and a tachometer generator. The reduction
gear has an independent dry-sump oil system. The reduction gear train is in two stages,
providing an overall reduction of 13.54 to 1 between engine speed (13.820 rpm) and propeller
shaft speed (1021 rpm).
2.1.3.1 Propeller Brake
The cone-type propeller brake acts on the first stage of reduction gearing. During engine
operation, it is held disengaged by gearbox oil pressure when rpm exceeds 23 percent and is
engaged this below speed.
2.1.7 Engine Controls and Control System
Engine control in the flight range of operation is based on regulation of engine speed by
propeller constant-speed governing and control of torque through regulation of fuel flow. Note
that the throttle acts only as a power control. It exercises no direct control over the propeller,
which is controlled entirely by the propeller regulator to regulate engine speed and to limit the
low blade angle.
2.1.7.1 Throttles
The throttles are quadrant mounted on the flight control panel pedestal. Throttles movements are
transmitted through mechanical linkage to an engine-mounted coordinator. the coordinator
transmits the movements through mechanical linkage to the propeller and to the engine fuel
control, and it also actuates switches.
Throttle
2.1.7.4 Engine Condition Lever
Four pedestal-mounted condition levers are primarily controls for engine starting and stopping
and propeller feathering and unfeathering. They actuate both mechanical linkages and switches
that provide electrical control. Each lever has four placarded positions as follows :
1. Run is a detent position.
propeller is fully feathered when the engine fuel is shut off. If the lever is left at mid-position.
2.3 Fire Extinguishing System
A two-shot bromotrifluoromethane (BT) fire extinguishing system is connected through a series
of directional-flow valves to each of the four engine nacelles and to the APU compartment. The
extinguishing agent is contained in two bottled mounted in the left wheel-well. One bottle is
discharged each time the system is actuated. A checked valve prevents a discharged bottle
from being recharged when a fresh bottle is fired. Each bottle is charged to approximately
600 psi with nitrogen, the nitrogen acting as a propellant for the BT. Individual gauges on each
bottle show charged bottle.
2.4 Propellers
Each engine is equipped with a Hamilton Standard, four-blade, electro-dydromatic,
full-feathering, reversible-pitch propeller. The propeller operates as a controllable-pitch propeller
for throttle settings below flight idle and as a constant-speed propeller for throttle settings of
flight idle or above. The major components of the propeller system are the propeller assembly,
the synchro-phasing system, the control system, and the anti-icing and deicing system.
2.4.1 Propeller Assembly
The propeller is made up of the propeller blades, barrel assembly, dome assembly,
spinner assembly, control assembly, and the anti-icing and deicing assembly.
2.4.1.1 Propeller Blades
The propeller blades are solid alumininum alloy with hollow shanks for weight reduction. On the
mounting end of the blades are located the blade gear segment, thrust bearings, oil seals,
and deicing rings.
2.4.1.2 Barrel Assembly
The principal functions of the barrel assembly are to retain the blades within the propeller
assembly, to provide the necessary means of attaching the propeller to the engine shaft,and to
transmit engine torque to the blades. The barrel assembly is made in two sections that are
bolted together to retain the propeller blades. An extension on the rear half of the assembly is
machined to fit over the splined engine shaft.
2.4.1.3 Dome Assembly
The dome assembly is mounter on the forward section of the barrel assembly. It contains the
pitch changing mechanism and the low-pitch stop assembly. The pitch changing mechanism
converts hydraulic pressure into mechanical torque. Its main parts are a piston assembly,
a stationary cam, a rotating cam, and the dome shell. The piston is a double-walled assembly
that fits over the two cams inside the dome shell. The piston is held in place by rollers that ride
in the cam tracks of both cams. The rear of rotating cam is connected by beveled gears to the
propeller blades. As hydraulic pressure is applied to the piston, causing it to move, the rollers
riding in the cam tracks turn the rotating cams, changing the blade angle. The low-pitch stop in
the dome mechanically stops the piston from decreasing blade angle below the flight range.
The low-pitch stop is retracted to allow lower blade angles during ground operation.
2.4.1.4 Control Assembly
The propeller control assembly in mounted on the aft extension of the propeller barrel but does
not rotate. it contains the oil reservoir, pumps, valves, and control components that supply the
pitch changing mechanism with hydraulic pressure of the propeller magnitude and direction to
vary the propeller blade angle as required for the selected operating condition. The valve
housing assembly section of the control assembly contains the flyweight speed-sensing pilot
valve, feather valve, feather solenoid valve, and feather actuating valve. The pump housing
assembly contains a scavenge, main, and standby pump, and an electrically driven,
double-element, auxiliary pump.
2.4.1.5 Spinner Assembly
The spinner assembly, which improves the aerodynamic characteristics of the propeller
assembly, enclose the dome, barrel, and control assemblies. It consists of a front section,
and a non-rotating after-body assembly. Cooling air is admitted through the air inlet at the front
of the spinner and passes over the dome assembly, barrel assembly, and control assembly fins,
and exhaust through vents in the engine nacelle.
2.4.1.6 Anti-icing and Deicing Assembly
The anti-icing and deicing assembly is made up of stationary and movable contacts for
conducting electrical power to the resistance-type heating elements on the leading edge and
shank of each blade and the entire spinner assembly.
2.4.2 Propeller Speed Control System
The speed of the propeller is controlled by the propeller governing system and
synchro-pahsing system.
2.4.2.1 Propeller Governing System
The principal function of the propeller governing system is to maintain constant engine
operating rpm. Propeller governing is accomplished by the action of the flyweight
speed-sensing pilot valve. The valve is controlled by the mechanical action of the flyweightopposing to the tension of the speeder spring. When the propeller is in an on-speed condition,
the pilot valve meters sufficient to the increased pitch or forward side of the dome assembly
piston to overcome twisting movement and maintain required blade angle. When an over-speed
condition occurs, the flyweight force overcomes the speeder spring force, and the pilot valve
moves to increase the flow to the increased-pitch side of the piston. If the propeller slows below
governed speed, the force of the speeder spring overcomes the force exerted by the flyweight,
and the pilot valve meters fluid to the aft side of the dome assembly piston to decrease blade
angle and allow the propeller to increase speed. The low-pitch stop prevents the propellers
from decreasing blade angle below the flight range. while the throttle are in the flight range.
2.4.2.2 Synchrophasing System/Electronic Governing
The synchrophaser electronic unit provides circuits for the following governing functions:
speed stabilization (derivative), throttle anticipation, and synchrophasing. The propeller
mechanical governor will hold a constant speed in the flight range but throttle changes will cause
the governor overspeed or underspeed while trying to compensate for the change in power.
A stabilization circuit stabilizes the mechanical governor during these changes when the
propeller governor control switch is in the NORMAL/NORM position by sending a signal to the
speed bias servo control motor to change the speeder spring compression. The throttle
anticipation circuit stabilizes the propeller speed during rapid movement of the throttle when the
propeller governor control switch is in the NORMAL position. Throttle movement rotates the
anticipation potentimeter in the propeller control assembly sending a signal to the anticipation
circuit which sends amplified signal to the speed bias servo control motor to change the
speeder spring compression. The synchrophasing system acts to keep all the propellers turing
at the same speed, and it maintains a constant blade rotational position relationship to
decrease vibration and to lower the noise level.
2.4.3 Negative Torque Signal Lockout System
2.4.4 Propeller Controls
Propeller controls include the throttles, condition levers, SYNCHROPHASING MATER switch,
....
2.4.4.1 Throttles
Each is mechanically linked through the engine coordinator to an input shaft on the propeller
control assembly. When the throttle is in the governing range, between FLIGHT-IDEL and
TAKE-OFF positions, the input shaft rotates with throttle movement but has no effect on
propeller speed. When the throttle is in the range below FLIGHT IDLE, any movement of the
throttle is transmitted to the speed-sensing pilot valve to increase or decrease blade angle.
The maximum negative blade angle is obtained when the throttle is at MAXIMUM REVERSE.
Approximate minimum thrust angle is obtained when the throttle is at GROUND IDLE. When the
throttle is moved below FLIGHT IDLE, a cam locks out the NTS system and a switch interrupts
sychrophaser signals to the propeller.
2.4.4.2 Engine Condition Levers
The engine condition levers serve primarily as feathering and unfeathering control. Each lever
is mechanically linked to the engine coordinator, which transmits the motion of the lever to the
propeller linkage only when it is moved to the FEATHER position.
2.5 Oil System
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