MODULE 15 CHAPTER 2 QUIZ 1

NOTE

TO CHECK YOUR PREPARATION ,PLZ WRITE DOWN YOUR SELECTED OPTIONS (A,B,C) ON ROUGH PAGE AND  AT THE END OF QUIZ , VERIFY YOUR SELECTED OPTIONS WITH THE CORRECT OPTIONS GIVEN BELOW

1. Ram effect due to aircraft forward speed will cause the efficiency of the engine to.

A. remain constant.

B. decrease.

C. increase.

2. The efficiency of a gas turbine engine at altitude.

A. decreases.

B. remains constant.

C. increases.

3. Which statement is true regarding jet engines?.

A. At the higher engine speeds, thrust increases rapidly with small increases in RPM.

B. At the lower engine speeds, thrust increases rapidly with small increases in RPM.

C. The thrust delivered per pound of air consumed is less at high altitude.

4. Some turboprop and turbojet engines are equipped with two spool or split compressors. When these engines are operated at high altitudes, the.

A. low pressure rotor will increase in speed as the compressor load decreases in the lower density air.

B. low pressure rotor will decrease in speed as the compressor load decreases in the lower density air.

C. throttle must be retarded to prevent overspeeding of the high pressure rotor due to the lower density air.

5. Ram effect' due to aircraft forward speed will cause the thrust of the engine to.

A. remain constant.

B. decrease.

C. increase.

6. With a fixed throttle, and with increased massairflow, what happens to EPR?.

A. EPR goes up.

B. EPR remains constant.

C. EPR goes down.

7. At what stage in a gas turbine engine are gas pressures the greatest?

A. Compressor outlet.

B. Turbine outlet.

C. Compressor inlet.

.

8. Increasing ram effect with increased speed.

A. reduces thrust due to reduced compressor efficiency.

B. increases thrust due to increased maximum airflow.

C. reduces thrust due to reduced turbine temperature.

9. The highest heat to metal contact in a jet engine is the.

A. burner cans.

B. turbine inlet guide vanes.

C. turbine blades.

10. Which compressor type gives the greatest advantages for both starting flexibility and improved high altitude performance?.

A. Single spool, axial flow.

B. Dual stage, centrifugal flow.

C. Split spool, axial flow.

ABOVE QUESTIONS WITH ANSWERS 

1. Ram effect due to aircraft forward speed will cause the efficiency of the engine to.

A. remain constant.

B. decrease.

C. increase.

Ans : increase.

Explanation: Ram effect improves compression ratio which improves thrust without using extra fuel Rolls Royce The Jet engine Page 219 refers.

2. The efficiency of a gas turbine engine at altitude.

A. decreases.

B. remains constant.

C. increases.

Ans : increases.

Explanation: The compressor performs better at lower air temperatures(see Jeppersen Gas Turbines Page 2-33) thus improving thermal efficiency. Also lower air temperatures up to the tropopause assist in maintaining Propulsive Efficiency(whilst accepting that decreasing density decreases mass flow). Also note that operators fly at the tropopause whenever possible even for short flights for the best SFC.

3. Which statement is true regarding jet engines?.

A. At the higher engine speeds, thrust increases rapidly with small increases in RPM.

B. At the lower engine speeds, thrust increases rapidly with small increases in RPM.

C. The thrust delivered per pound of air consumed is less at high altitude.

Ans : At the higher engine speeds, thrust increases rapidly with small increases in RPM.

Explanation: Jeppesen A&P Powerplant Textbook 3-43.

4. Some turboprop and turbojet engines are equipped with two spool or split compressors. When these engines are operated at high altitudes, the.

A. low pressure rotor will increase in speed as the compressor load decreases in the lower density air.

B. low pressure rotor will decrease in speed as the compressor load decreases in the lower density air.

C. throttle must be retarded to prevent overspeeding of the high pressure rotor due to the lower density air.

Ans : low pressure rotor will increase in speed as the compressor load decreases in the lower density air.

Explanation: Jeppesen A&P Powerplant Textbook 3-18.

5. Ram effect' due to aircraft forward speed will cause the thrust of the engine to.

A. remain constant.

B. decrease.

C. increase.

Ans : remain constant.

Explanation: Thrust is constant, but efficiency will increase.

6. With a fixed throttle, and with increased massairflow, what happens to EPR?.

A. EPR goes up.

B. EPR remains constant.

C. EPR goes down.

Ans : EPR goes down.

Explanation: With increasing mass airflow with throttles fixed Ram pressure (Pt2) increases but the P7 pressure remains the same. Jeppesen Aircraft Gas Turbines page 12-18 refers.

7. At what stage in a gas turbine engine are gas pressures the greatest?

A. Compressor outlet.

B. Turbine outlet.

C. Compressor inlet.

Ans : Compressor outlet.

Explanation: NIL.

8. Increasing ram effect with increased speed.

A. reduces thrust due to reduced compressor efficiency.

B. increases thrust due to increased maximum airflow.

C. reduces thrust due to reduced turbine temperature.

Ans : increases thrust due to increased maximum airflow.

Explanation: Jepperson Gas Turbine Powerplants Page 2-35 refers.

9. The highest heat to metal contact in a jet engine is the.

A. burner cans.

B. turbine inlet guide vanes.

C. turbine blades.

Ans : turbine inlet guide vanes.

Explanation: NIL.

10. Which compressor type gives the greatest advantages for both starting flexibility and improved high altitude performance?.

A. Single spool, axial flow.

B. Dual stage, centrifugal flow.

C. Split spool, axial flow.

Ans : Split spool, axial flow.

Explanation: NIL.