Aircraft Design Questions and Answers – Propulsion Selection

This set of Aircraft Design Multiple Choice Questions & Answers (MCQs) focuses on “Propulsion Selection”.

1. Which of the following is not an aircraft propulsion system?
a) Reciprocating engine
b) High lift device
c) Piston engine
d) Rocket engine
View Answer

Answer: b
Explanation: High lift devices are not part of aircraft propulsion system. High lift device is used to increase lift produced. Flaps are an example of high lift device which are used at takeoff and landing.

2. Which of the following is not the type of an aircraft propulsion?
a) Rocket engine
b) Air breathing propulsion
c) Non air breathing propulsion
d) Longerons
View Answer

Answer: d
Explanation: Longerons are structural elements of an aircraft. Longerons are heavy structural members that run straight and used to prevent bending.

3. Which of the following is an advantage of the piston prop engine?
a) Supersonic speed always
b) Highest speed
c) Cheap and low fuel consumption
d) Limited performance
View Answer

Answer: c
Explanation: Piston prop engine are widely used during early era. Piston prop engine provides cheap and low fuel consumption. Piston prop engine suffers from speed limits.
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4. Which of the following is part of a turbine engine?
a) compressor
b) Flap
c) Aileron
d) Elevator
View Answer

Answer: a
Explanation: Compressor is an integral part of turbine engine. Flap is secondary control surface. Aileron and elevator are primary control surface. Aileron is used for rolling motion and elevator is used for pitching motion.

5. A typical turbine engine consists of __________
a) only turbine
b) combustion chamber, turbine and compressor
c) only compressor and turbine
d) turbine and combustion chamber only
View Answer

Answer: b
Explanation: A turbine engine is widely used engine in aviation sector. A typical turbine engine consists of following fundamental parts: Compressor, combustion chamber and turbine. Apart from this, most fighter aircrafts consist of afterburning section.

6. What is the function of a compressor?
a) To generate work
b) To increase velocity of flow
c) To expand flow
d) To increase pressure and temperature
View Answer

Answer: d
Explanation: Compressor is used to compress the flow. Compressor Increases pressure and temperature of the flow flowing through it. Due to increase in pressure, velocity of the flow reduces. Flow expansion can be achieved through nozzle.

7. What is the use of Turbine?
a) To compress the flow
b) Generate work to drive shaft
c) To increase pressure
d) To increase temperature
View Answer

Answer: a
Explanation: Turbine is an essential component of gas turbine engine. Turbine is used to decrease temperature and pressure of the gas. Combustion products pressure is reduced by turbine. Turbine generates work to drive the shaft.
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8. Which of the following is correct?
a) Compressor consumes work produced by turbine
b) Compressor produces work to drive shaft
c) Compressor increases velocity of the flow
d) Lift is always same as weight
View Answer

Answer: a
Explanation: Turbine generates work to drive the shaft. This work is consumed to drive compressor. Compressor doesn’t produce work. Lift is not always same as weight. Compressor is used to increase pressure and temperature.

9. Which of the following is a type of compressor?
a) Incline compressor
b) Centrifugal compressor
c) Flap
d) Rudder compressor
View Answer

Answer: b
Explanation: Centrifugal Compressor is type of compressor. Centrifugal compressor uses centrifugal force to fling the air. Flow does not coincide with axis of rotation. Flap is secondary control surface of an aircraft.
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10. Following diagram represents __________
Piston prop engine relies piston to generate useful work and thrust
a) turbojet
b) turboprop
c) piston prop
d) rocket
View Answer

Answer: c
Explanation: Piston prop engine is shown in above diagram. A typical piston prop engine relies piston and propeller blades to generate useful work and thrust. They are heavy and produces more noise.

11. Following diagram represents ___________
Turbojet with centrifugal compressor for combustion chamber and turbine stage
a) turboprop design
b) piston engine
c) piston prop aircraft
d) turbojet engine with centrifugal compressor
View Answer

Answer: d
Explanation: A typical Turbojet with centrifugal compressor is shown in above schematic diagram. Centrifugal force is used as working principle to drive this type of compressor. As shown in figure, it consists of combustion chamber and turbine stage as well.

12. Following diagram represents ___________
Turbojet engine is operated by axial flow Compressor
a) turbofan
b) typical turbo jet
c) turboprop
d) reciprocating
View Answer

Answer: b
Explanation: As shown in figure, a typical Turbojet engine is shown. Here, turbojet engine is operated by axial flow Compressor as shown in the above schematic diagram. As air passes through Compressor, pressure will increase and then it will be directed to combustion and preceding stages.

13. Following diagram represents ___________
Diagram representating type of prop connected to turbine engine via gear box
a) turboprop
b) rocket
c) ramjet
d) scramjet
View Answer

Answer: a
Explanation: A turboprop is different from traditional piston prop engine. Here, propeller is connected to turbine engine via gear box. Rocket is type of aircraft and spacecraft propulsion system.

14. Following diagram represents ___________
Typical turbofan engine
a) turbofan
b) turbojet
c) piston engine
d) to and fro engine
View Answer

Answer: a
Explanation: A typical turbofan engine is shown in the above diagram. Turbofan operates with same principle as other has turbine engine. However, it has a fan mounted at inlet as shown. Fuel Efficiency of such engine is more than typical Turbojet.

15. Following diagram represents ___________
Speed limit chart of current propulsion system in aviation
a) lift curve slope
b) drag polar
c) typical speed limit chart of propulsion system
d) lift coefficient variation
View Answer

Answer: c
Explanation: Above diagram is used to show the typical speed limit chart of current propulsion system in aviation. As shown turboprop and piston prop cannot be used for speeds beyond Mach 1. Lift curve slope is defined as change in lift coefficient per change in angle of attack.

Sanfoundry Global Education & Learning Series – Aircraft Design.

To practice all areas of Aircraft Design, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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