11.1 Speed Of Sound

Question 1

What is speed of sound also known as ?

Answer 1

Mach 1

Question 2

What is the Mach number equation ?

Answer 2

Mach number = velocity of object (V) / speed of sound (a)

Question 3

What is the compressible flow speed of subsonic ?

Answer 3

Mach number less than 0.8

Question 4

What is the compressible flow speed of transonic ?

Answer 4

Mach numbers from 0.8 to 1.2

Question 5

What is the compressible flow speed of supersonic ?

Answer 5

Mach numbers from 1.2 to 5.0

Question 6

What is subsonic flight ?

Answer 6

Is a flight phase which aircraft’s operate at speeds below speed of sound
Most commercial and general aviation flights occur in this region

Question 7

What is the behaviour of air in subsonic speeds ?

Answer 7

Air is approximated as incompressible

Question 8

What happens at transonic flight ?

Answer 8

As it reaches upper surface of wing air velocity reaches Mach 1 threshold
Leading to formation of a shock wave which forms at. 90 degree angle to air flow

Question 9

What happens at supersonic flight ?

Answer 9

All speeds around aircraft are higher than the speed of sound
Speeds above Mach 5 known as hypersonic range
Supersonic ranges from Mach 1.20 to 5.0