This set of Aircraft Performance Multiple Choice Questions & Answers (MCQs) focuses on “Thrust Producing Power Plant – 1”.
1. The forms of powerplant used in aircraft propulsion are ___________
a) thrust-producing and power producing
b) weight-producing and power producing
c) thrust-producing and weight producing
d) thrust-producing, power producing and weight producing
View Answer
Explanation: The two forms of powerplant used in aircraft propulsion are thrust-producing and power producing. Thrust-producing engines include turbojet, turbofan and rocket while power producing engines are get engine and piston engine.
2. What is thrust producing powerplant?
a) Propulsive force that is directed by increasing momentum of the airflow
b) Propulsive force that is obtained from shaft power by propeller
c) Propulsive force that is directed by decreasing momentum of the airflow
d) Propulsive force that is obtained from engine power by propeller
View Answer
Explanation: The two forms of powerplant used in aircraft propulsion are thrust-producing and power producing. A thrust-producing powerplant is the one whose propulsive force is obtained by increasing momentum of the airflow through the engine.
3. Which of the following is not a thrust-producing powerplant?
a) turbojet
b) turbofan
c) rocket
d) piston engine
View Answer
Explanation: The two forms of powerplant used in aircraft propulsion are thrust-producing and power producing. A thrust-producing powerplant is the one whose propulsive force is obtained by increasing momentum of the airflow through the engine. Examples of thrust-producing powerplant are turbojet, turbofan and rocket.
4. The high-energy air is expelled from the nozzle of an aircraft with decreased momentum.
a) True
b) False
View Answer
Explanation: The high-energy air is expelled from the nozzle of an aircraft with increased momentum to produce thrust to the aircraft. This process is occurred in the thrust-producing powerplant. Some examples of thrust-producing powerplant are turbojet, turbofan and rocket.
5. What is the function of the compressor in an aircraft?
a) To supply sufficient amount of air for combustion
b) Increase velocity
c) Decrease pressure
d) To cut off the air flow inside the aircraft
View Answer
Explanation: The function of the compressor in an aircraft to supply sufficient amount of air for combustion. In a compressor the velocity may increase or decrease accordingly but the pressure increases.
6. What is net propulsive force?
a) The stream force exited at the exit of the engine
b) The difference between the stream force entering and leaving the engine
c) The stream force entering at the entrance of the engine
d) The product of stream force entering and leaving the engine
View Answer
Explanation: The net propulsive force is the difference between the stream force entering and leaving the engine. It is represented by FN. The thrust produced by an aircraft is depended on the net propulsive force.
7. What is gross thrust?
a) Thrust produced at the exit of the nozzle
b) The difference between the stream force entering and leaving the engine
c) The stream force exited at the exit of the engine
d) The product of stream force entering and leaving the engine
View Answer
Explanation: The gross thrust is the thrust produced at the exit of the nozzle. It is represented by FG. It is also equal to the rate of change of momentum at the exhaust gas flow. The equation is given as FG=ṁVj where FG is gross thrust, ṁ is mass flow rate and Vj is exit velocity.
8. Flow due to intake flow is known as momentum drag.
a) True
b) False
View Answer
Explanation: Flow due to intake flow is known as momentum drag. It is the rate of change of momentum in the intake flow. It is represented by Dm. The equation is Dm=ṁV where Dm is momentum drag, ṁ is mass flow rate and V is air intake flow.
9. The net propulsive thrust is given by _________
a) FN=FG-Dm
b) FN=FG+Dm
c) FN=FG*Dm
d) FN=FG/Dm
View Answer
Explanation: The net propulsive thrust is given by FN=FG-Dm where FN is net propulsive force, FG is gross thrust and Dm is momentum drag. The net propulsive force is the difference between the stream force entering and leaving the engine. Flow due to intake flow is known as momentum drag. The gross thrust is the thrust produced at the exit of the nozzle.
10. What kind of forces is responsible for airframe drag?
a) Forces resulting from external flow
b) Forces resulting from internal flow
c) Forces resulting from discontinuous flow
d) Forces resulting from continuous flow
View Answer
Explanation: The external flow can result in generation of forces. These forces that are caused due to external flow is known as airframe drag. In general there are three types of drags. They are parasitic drag, induced drag and wave drag.
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