TM 1-1520-238-T-4
4–22
4–7
SYSTEM DESCRIPTION (cont)
4–7
(2) Engine Exhaust Subsystem.
The engine exhaust subsystem directs and cools engine exhaust
gases and removes foreign particles from the engine. During engine operation, exhaust gas from the engine is
forced through the primary nozzle into the secondary nozzle. The flow of exhaust gas from the primary to the
secondary nozzle draws ambient (outside) air into the nacelle which creates an ejector pumping action. The
ambient air in the nacelle is drawn into the secondary nozzle which causes the air to mix with the exhaust gas as
it leaves the primary nozzle. The air mixing reduces the temperature of the exhaust gas and the remaining heat is
absorbed by the secondary exhaust nozzle. The fins on the secondary exhaust nozzle emits the remaining heat
which lowers the temperature of the exhaust gas leaving the nozzle. The air duct receives air and foreign particles
(if any) from the inlet particle separator (IPS) blower. The duct routes particles to the primary nozzle where it
mixes with the exhaust gas.
SPRING
ENGINE
NACELLE
COOLING LOUVER ACTUATOR
M58-209A
PISTON
COOLING
LOUVERS
(OPEN)
COOLING LOUVER
ACCESS DOOR
LOWER FIXED
LOUVERS
Figure 4–13.
Right Engine Cooling Louver Operation
SECONDARY
NOZZLE
LH NACELLE
PRIMARY
NOZZLE
FIXED
LOUVERS
IPS DUCT
IPS
BLOWER
ENGINE INLET AIR
OUTSIDE AIR
DECK AIR
MAIN TRANSMISSION
HEAT EXCHANGER
LOUVERS
FIREWALL
M58-210
Figure 4–14.
Engine Cooling and Exhaust Operation
