AMS 274 TURBINES FINAL PRACTICE
EXAMINATION 2026 QUESTIONS
WITH ANSWERS GRADED A+
◍ Brayton Cycle.
Answer: continuous thermodynamic cycle of the gas turbine engine.
"constant pressure cycle".Intake, compression, expansion (power), and
exhaust
◍ Describe the Brayton Cycle.
Answer: Intake, compression, combustion/burner (mix fuel and air to light
on fire) and exhaust. These are all occurring simultaneously.THINK: suck,
squeeze, bang, blowUsed in gas turbine engines
◍ What is Compressor Pressure Ratio (CPR).
Answer: it is the ratio of pressure at the turbines exhaust to the turbines inlet.
◍ Bernoulli.
Answer: as the velocity of a fluid increases, the pressure exerted by the fluid
decreases.Air acts as an incompressible fluid would act when flowing at
subsonic flow rates
◍ What is the CPR formula.
Answer: CPR = Pexit / Pinlet
◍ High CPR causes what?.
Answer: Better combustion and fuel efficiency
◍ Dr. Sanford
A. Moss (American - GE).
Answer: Published a thesis on gas turbine engines in 1900.In 1918, while
working at General Electric Company as an engineer, he supervised the
, production of the gas turbine driven turbosupercharger for recip engines.
◍ Sir Frank Whittle (British).
Answer: 1936, he patented the first turbofan engineMay 1941, W-1
Turbojet. The W-1 used an impeller compressor, annular combustor, and a
single stage turbineLargest obstacle he had to overcome was obtaining the
necessary high temp strength metals for the combustion & turbine section
◍ Hans Von Ohain (German).
Answer: first pure jet-propelled flight in history in August of 1939.
◍ Advantages of free turbines.
Answer: - low noise, low blade erosion; prop held at very low rpm during
taxing- engines easier to start ; cold days- prop & its gearbox don't directly
transmit vibrations into gas generator- when engine shut down not desired;
rotor brake used to stop prop movement during aircraft loading
◍ Disadvantages of free turbines.
Answer: - risks of overspeed- loss of load : uncontrollable acceleration due
to loss of gearbox- separate shafts
◍ APU.
Answer: Supply electrical power and pressurized air when main engines are
not operating.Do NOT require power lever
◍ Why do Modern Axial Compressors have multiple stages?.
Answer: It better increases and improves CPR
◍ What does an APU not have.
Answer: Centrifugal flow compressorHydraulic power
◍ Otto Cycle.
Answer: Intake, compression, expansion (power), and exhaust
◍ What are the advantages of Free turbines?.
Answer: 1. Rotor Brake Capable 2. Vibration Isolation3. Easier starting --
Especially in cold weather 4. Lower propeller RPM
◍ Newton's 1st Law.
EXAMINATION 2026 QUESTIONS
WITH ANSWERS GRADED A+
◍ Brayton Cycle.
Answer: continuous thermodynamic cycle of the gas turbine engine.
"constant pressure cycle".Intake, compression, expansion (power), and
exhaust
◍ Describe the Brayton Cycle.
Answer: Intake, compression, combustion/burner (mix fuel and air to light
on fire) and exhaust. These are all occurring simultaneously.THINK: suck,
squeeze, bang, blowUsed in gas turbine engines
◍ What is Compressor Pressure Ratio (CPR).
Answer: it is the ratio of pressure at the turbines exhaust to the turbines inlet.
◍ Bernoulli.
Answer: as the velocity of a fluid increases, the pressure exerted by the fluid
decreases.Air acts as an incompressible fluid would act when flowing at
subsonic flow rates
◍ What is the CPR formula.
Answer: CPR = Pexit / Pinlet
◍ High CPR causes what?.
Answer: Better combustion and fuel efficiency
◍ Dr. Sanford
A. Moss (American - GE).
Answer: Published a thesis on gas turbine engines in 1900.In 1918, while
working at General Electric Company as an engineer, he supervised the
, production of the gas turbine driven turbosupercharger for recip engines.
◍ Sir Frank Whittle (British).
Answer: 1936, he patented the first turbofan engineMay 1941, W-1
Turbojet. The W-1 used an impeller compressor, annular combustor, and a
single stage turbineLargest obstacle he had to overcome was obtaining the
necessary high temp strength metals for the combustion & turbine section
◍ Hans Von Ohain (German).
Answer: first pure jet-propelled flight in history in August of 1939.
◍ Advantages of free turbines.
Answer: - low noise, low blade erosion; prop held at very low rpm during
taxing- engines easier to start ; cold days- prop & its gearbox don't directly
transmit vibrations into gas generator- when engine shut down not desired;
rotor brake used to stop prop movement during aircraft loading
◍ Disadvantages of free turbines.
Answer: - risks of overspeed- loss of load : uncontrollable acceleration due
to loss of gearbox- separate shafts
◍ APU.
Answer: Supply electrical power and pressurized air when main engines are
not operating.Do NOT require power lever
◍ Why do Modern Axial Compressors have multiple stages?.
Answer: It better increases and improves CPR
◍ What does an APU not have.
Answer: Centrifugal flow compressorHydraulic power
◍ Otto Cycle.
Answer: Intake, compression, expansion (power), and exhaust
◍ What are the advantages of Free turbines?.
Answer: 1. Rotor Brake Capable 2. Vibration Isolation3. Easier starting --
Especially in cold weather 4. Lower propeller RPM
◍ Newton's 1st Law.
