Turboprops

Question 1

Most effective speed range and height?

Answer 1

300-350mph

20,000 ft

Question 2

What is a gas coupled engine?

Answer 2

No mechanical connection between generator and turbine

Question 3

Types of reduction gearboxes?

Answer 3

2 stage spur
Annular epicyclic spur
Bevel epicyclic
Compound epicyclic spur

Question 4

Which type of gearbox will cause the prop to turn in the opposite direction to the engine?

Answer 4

Rotary annular engine

Question 5

What over speed devices are generally found on free power engines?

Answer 5

NF governor

Over speed governor

Question 6

How does an inertial particle separator work?

Answer 6

Convergent path causes the heavy particles to miss the inlet to the engine due to their velocity and mass, while the air can still make it in.

Question 7

What is the beta range of control, and what is used to control the prop in this range?

Answer 7

Ground operation

Power lever

Question 8

How many housings is a two stage spur reduction gearbox split into and can it be split in the field?

Answer 8

3 housings

Can’t be split in field

Question 9

What are the characteristics of a helically cut gear and how can this be utilised in a turboprop reduction gear?

Answer 9

More area to transmit
Some thrust measuring torque
Utilised like a rotating annulus gearbox