11 Quiz HIGH SPEED FLIGHT

Calculate the Mach Number, given the following conditions: TAS 385 Knots, CAS 293 kts, Temp -48 °C

• M 0.552
• M 0.503
• M 0.421
• M 0.659

Assuming ISA conditions, climbing at a constant Mach number up to the tropopause the TAS will:

• decrease.
• remain constant.
• first increase, then decrease.
• increase.

During a descent at a constant Mach number (assume zero thrust and standard atmospheric conditions):

• the angle of attack will decrease.
• the descent angle will decrease.
• the pitch angle will increase.
• the TAS will decrease.

Regarding the transonic speed range:

• it starts at a Mach number just above 1.
• both subsonic and supersonic speeds exist in the flow around the aeroplane.
• it starts at Mcrit and extends to Mach number equal to 1.
• it starts at a Mach number equal to 1.

When the air is passing through a shock wave the density will:

• decrease.
• decrease and beyond a certain Mach number start increasing again.
• increase.
• stay constant.

Behind a normal shock wave on an aerofoil section the local Mach number is:

• higher than before.
• lower than before but still greater than 1.
• less than 1.
• equal to 1.

Which statement is correct about a normal shock wave?

• The airflow changes direction.
• The airflow expands when passing the aerofoil.
• The airflow changes from subsonic to supersonic.
• The airflow changes from supersonic to subsonic.

In a normal shockwave there will be:

• An increase in pressure, increase in temperature, increase in density and a decrease in velocity
• An increase in pressure, increase in temperature, decrease in density and a decrease in velocity
• An decrease in pressure, increase in temperature, increase in density and a decrease in velocity
• An increase in pressure, increase in temperature, increase in density and a increase in velocity

Above Mcrit in the transonic speed regime, at a constant angle of attack, the CD will…

• remain constant in the entire regime.
• vary depending on Mach number.
• decrease as Mach number increases.
• increase as Mach number increases.

When shock stall occurs, lift will decrease because:

• of the existence of a shock wave being located at the trailing edge of the wing.
• Mcrit is reached.
• the bow wave appears.
• flow separation occurs behind the shock wave.