Chap 2 : Overview of Engines

Question 1

Categories of engines

Answer 1

Piston engines
Military low-bypass engines
Civil turbofan engines
Turboprop engines
Turboshaft engines
Rocket engines

Question 2

Dvt of engines over the years

Answer 2

1903 : 1st piston engine
1928 : 1st rocket engine
1939 : 1st military low-bypass engine
1945 : 1st turboprop engine
1951 : 1st turboshaft engine
1970’s : 1st high-bypass civil turbofan engine

Question 3

Cycles use for piston engines ?

Answer 3

Ideal/real P-V cycle, ideal T-S cycle

Question 4

Types of piston engines ?

Answer 4

Star engine
Rotary engine
V-engine
Boxer engine
In-line engine

Question 5

What’s the big drawback of piston engines ?

Answer 5

70-75% of the fuel energy is lost

Question 6

Power equation of a 4-stoke piston engine ?

Answer 6

P = number of cylinders × cubic capacity × indicated average pressure × rotational speed/2

Question 7

Reasons why piston engines were replaced by jet engines ?

Answer 7

Higher power/weight
More compact design
Continuous process => more reliable
Less vibrations => less noisy
Less fuel consumption

Question 8

Pros & cons of turboprop engines ?

Answer 8

Pros :
Low fuel consumption/passenger
Simple and robust
Efficient at low speeds and short to medium-range flights

Cons :
Limited to low speeds
Noisy
Always need a gear box => propeller integration issues

Question 9

Pros & cons of turbofan engines ?

Answer 9

Pros :
Less drag
Low noise levels
Efficient at high speeds and long-range flights

Cons :
Bad for regional-range flights
Complex & expensive
Heavy

Question 10

What are the potential future engines & technologies ?

Answer 10

A geared turbofan (Rolls Royce Ultra Fan)
An Open-Rotor (turboprop by Safran)
Electric/hybrid propulsion