AMS 274 Turbines Final Exam Questions with
Detailed Verified Answers
If the anti-ice air valve is open what happens to EGT? Ans: EGT increases
(tachometer and EPR also shift)
How do you calculate EPR? Ans: Turbine discharge/Compressor inlet pressure
What are the most common type of thermocouples used? Ans: Chromel/Alumel (CA)
What do the older style APUs have in them? Ans: Governors
What is the typical gear down ratio for pneumatic starters? Ans: 25:1
What is the starting sequence for turbine engines? Ans: Starter --> Ignition --> Fuel
you hear a clicking noise from the pneumatic starter it indicates: Ans: The pawls re-
engaging (normal)
Typical air flow in a pneumatic starter: Ans: Air flows into the starter --> Stator vanes
(designed to choke in order to prevent overspeed) --> Turbine
What was Whittle famous for? Ans: Invented the jet engine
What are the 4 types of gas turbines and typical aircraft they are found on: Ans: 1.
Turbojet (supersonic)
2. Turbofan (large commercial)
3. Turboprop (larger GA)
4. Turboshaft (helicopters)
What is the Brayton Cyle? Ans: thermodynamic cycle that explains how gas turbine
engines run
, Bernoulli's principle: Ans: As the velocity of a fluid increases, the pressure exerted by
the fluid decreases (convergent ducts: velocity increases and pressure
decreases/divergent ducts: velocity decreases and pressure increases)
What company produced the first gas turbine engine in the U.S.? Ans: General Electric
In a split-spool/dual-spool/twin-spool turbine, what drives what? Ans: The low-speed
turbine drives the first compressor
The high speed turbine drives the second compressor
What is typically found in a turboshaft engine? Ans: A power turbine
What is the low bypass, medium bypass, and high bypass general engine ratios? Ans:
Low: 1:1
Medium: 2:1 to 3:1
High: 4:1 to 9:1
What is another name for an impeller? Ans: A centrifugal compressor
What does Fn stand for? Ans: Thrust net
What does Fg stand for? Ans: Static thrust (gross thrust)
How do you calculate bypass ratio? Ans: airflow of the fan/airflow of the core
What do inlet guide vanes do, and are they part of the compressor? Ans: Stationary
airfoils which proceed the 1st stage compressor rotor blades and are used to direct air
into the blades at the optimal angle (No, they are not part of the compressor)
What are the 4 types of jets? Ans: 1. Rocket (operate outside of the atmosphere)
2. Turbo jet
© Get it right 2025 Getaway - Stuvia US All rights reserved
Detailed Verified Answers
If the anti-ice air valve is open what happens to EGT? Ans: EGT increases
(tachometer and EPR also shift)
How do you calculate EPR? Ans: Turbine discharge/Compressor inlet pressure
What are the most common type of thermocouples used? Ans: Chromel/Alumel (CA)
What do the older style APUs have in them? Ans: Governors
What is the typical gear down ratio for pneumatic starters? Ans: 25:1
What is the starting sequence for turbine engines? Ans: Starter --> Ignition --> Fuel
you hear a clicking noise from the pneumatic starter it indicates: Ans: The pawls re-
engaging (normal)
Typical air flow in a pneumatic starter: Ans: Air flows into the starter --> Stator vanes
(designed to choke in order to prevent overspeed) --> Turbine
What was Whittle famous for? Ans: Invented the jet engine
What are the 4 types of gas turbines and typical aircraft they are found on: Ans: 1.
Turbojet (supersonic)
2. Turbofan (large commercial)
3. Turboprop (larger GA)
4. Turboshaft (helicopters)
What is the Brayton Cyle? Ans: thermodynamic cycle that explains how gas turbine
engines run
, Bernoulli's principle: Ans: As the velocity of a fluid increases, the pressure exerted by
the fluid decreases (convergent ducts: velocity increases and pressure
decreases/divergent ducts: velocity decreases and pressure increases)
What company produced the first gas turbine engine in the U.S.? Ans: General Electric
In a split-spool/dual-spool/twin-spool turbine, what drives what? Ans: The low-speed
turbine drives the first compressor
The high speed turbine drives the second compressor
What is typically found in a turboshaft engine? Ans: A power turbine
What is the low bypass, medium bypass, and high bypass general engine ratios? Ans:
Low: 1:1
Medium: 2:1 to 3:1
High: 4:1 to 9:1
What is another name for an impeller? Ans: A centrifugal compressor
What does Fn stand for? Ans: Thrust net
What does Fg stand for? Ans: Static thrust (gross thrust)
How do you calculate bypass ratio? Ans: airflow of the fan/airflow of the core
What do inlet guide vanes do, and are they part of the compressor? Ans: Stationary
airfoils which proceed the 1st stage compressor rotor blades and are used to direct air
into the blades at the optimal angle (No, they are not part of the compressor)
What are the 4 types of jets? Ans: 1. Rocket (operate outside of the atmosphere)
2. Turbo jet
© Get it right 2025 Getaway - Stuvia US All rights reserved
