FAA Aviation Mechanic Powerplant (AMP)Turbine EnginesEasy
A technician is comparing thrust reverser designs on different turbofan engines. Which type uses hinged doors that rotate into the exhaust stream to physically block the duct and redirect exhaust gas forward?
- AVariable exhaust nozzle reverser
- BTarget (clamshell) type reverser
- CCascade-type reverser
- DBlocker door fan-air-only reverser
Show answer & explanationAnswer & explanation
Correct answer: B. Target (clamshell) type reverser
A target (clamshell) reverser uses large hinged doors mounted at the rear of the tailpipe that rotate to physically block the entire exhaust flow, deflecting it forward to produce reverse thrust. This design is common on engines with a simple convergent nozzle rather than a bypass duct with cascade vanes.
Why the other options are wrong
- A. There is no standard 'variable exhaust nozzle reverser' design in turbine engines.
- C. Cascade reversers use blocker doors and fixed vanes in the fan duct to redirect bypass air, not hinged clamshell doors.
- D. This describes a component of cascade systems, not the target type.
Target (Clamshell) Thrust Reverser
A thrust reverser design using two hinged doors that rotate to fully block the exhaust duct and redirect exhaust gas forward, producing reverse thrust.
- Common on engines without a large bypass duct
- Doors physically close over the tailpipe exit
- Contrasts with cascade-type reversers used on high-bypass turbofans
Memory trick: Clamshell = a clam snapping shut over the exhaust pipe.