11.1.2 - High Speed Flight

Question 1

What has the most effect on the speed of sound and what is its speed at sea level?

Answer 1

Temperature of the air

Speed of sound at sea level = 1224 km/h

Question 2

What are the 4 sonic flight speed ranges?

Answer 2

Subsonic <0.75

Transonic 0.75 - 1.25

Supersonic 1.25 - 5

Hypersonic >5

(all numbers are in Mach)

Question 3

What happens to pressure, density and velocity in a supersonic venturi?

Answer 3

Constant temperature

Velocity down

Pressure Up

Density Up

Question 4

What happens to pressure, density and velocity in a subsonic venturi?

Answer 4

Constant Density

(Incompressible)
Velocity Up

Pressure Down

Density Constant

Question 5

What is Mach number?

Answer 5

Mach = speed of aircraft / Speed of sound

Question 6

The speed of sound is only affected by the ____ of the air

Answer 6

temperature

Question 7

High-speed flight is measured in terms of ____ ____

Answer 7

Mach number

Question 8

Answer 8

Subsonic = below Mach 0.75

Transonic = Mach 0.75 - 1.25

Supersonic = Mach 1.25 - 5

Hypersonic = Mach 5 +

Question 9

When an aeroplane if flying below the speed of sound in the transonic range, some of the air flowing over the airfoil has accelerated until it is supersonic and a ____ ____ ____ forms.

Air passing through this ____ ____ ____ slows to a subsonic speed without changing its direction

Answer 9

normal shock wave

normal shock wave

Question 10

For maximum effectiveness of Supersonic Engine Inlets, the air that flows into the inlet of a turbine engine must be ……

Answer 10

Slowed down to a subsonic velocity, even though the aircraft itself is flying at a supersonic speed