8. Basic aerodynamics - Q&A

The angle of attack which gives the best L/D ratio

• decreases when density decreases.
• in unaffected by density changes.
• increases when density decreases.

With increasing altitude the angle at which a wing will stall

• remains the same.
• reduces with altitude.
• increases with altitude.

Under what conditions will an aircraft create best lift?

• Hot damp day at 1200 ft.
• Cold dry day at 200 ft.
• Cold wet day at 1200 ft.

Due to the interference of the airflow on a high wing aircraft between the fuselage and the wings, the lateral stability of the aircraft in a gusty wind situation will cause

• the upper wing to increase its lift.
• the upper wing to decrease its lift.
• the lower wing to decrease its lift.

The relationship between induced drag and airspeed is, induced drag is

• directly proportional to the square of the airspeed.
• directly proportional to airspeed alone.
• inversely proportional to the square of the speed.

What effect does lowering flaps for takeoff have on aircraft speeds?

• Reduces takeoff speeds only.
• Reduces the landing speed only.
• Reduces both takeoff and landing speeds.

With respect to differential aileron control, which of the following is true?

• The up going and down going ailerons both deflect to the same angle.
• The up going Aileron moves through a smaller angle than the down going aileron.
• The down going aileron moves through a smaller angle than the up going aileron.

In a turn the up-going wing causes a

• de-stabilizing effect due to increased AoA.
• de-stabilizing effect due to decreased AoA.
• stabilizing effect due to decreased AoA.

If the aircraft is slipping in a turn

• the bank angle is too great.
• the bank angle is too small.
• the nose of the aircraft is positioned too low.

Due to the change in lift coefficient accompanying extension of the flaps, to maintain the lift constant it would be necessary to

• raise the nose.
• lower the nose.
• keep pitch attitude constant.

On a high winged aircraft in a banked turn, which of the following are true?

• The down-going wing loses lift producing a stabilizing effect.
• The up-going wing loses lift causing a stabilizing effect.
• The wing dihedral alone causes a stabilizing effect.

An aircraft left wing is flying low. The aileron trimmer control to the left aileron trim tab in the cockpit would be

• moved up causing the left aileron to move up.
• moved up causing the left aileron to move down.
• moved down causing the left aileron to move down.

As a subsonic aircraft speeds-up, its Centre of Pressure

• moves aft.
• moves forward.
• is unaffected.

The power required at low altitude for a given IAS is

• unchanged with altitude.
• higher.
• lower.

Ice formed on the leading edge will cause the aircraft to

• stall at a higher speed.
• stall at a lower speed.
• stall at the normal stall speed and AOA.

After a disturbance in pitch, an aircraft continues to oscillate at constant amplitude. It is

• longitudinally statically unstable.
• longitudinally dynamically neutral.
• laterally dynamically unstable.

An aircraft flying below the tropopause descends at a constant True Airspeed, its Mach. No. will

• stays constant.
• rise.
• decrease.

If the radius of a turn is reduced the load factor will

• increase.
• decrease.
• stay unchanged.

The amount of thrust produced by a jet engine or a propeller can be calculated using

• Newton's 3rd law.
• Newton's 2nd law.
• Newton's 1st law.

Deployment of flaps will result in

• a decrease in stall angle.
• an increase in stall angle.
• a decrease in angle of attack.

The ISA

• assumes a sea level temperature of 25 degrees C.
• is referenced from the equator.
• is taken from 45 degrees latitude.

Vortex generators are fitted to

• move transition point rearwards.
• move the transition point forwards.
• delay the onset of boundary layer separation.

Supersonic air going through an incipient shock wave will decrease its speed and

• decrease temperature and increase density.
• increase temperature and decrease density.
• increase temperature and increase density.

What effect would a forward CG have on an aircraft on landing?

• Increase stalling speed.
• Reduce the stalling speed.
• No effect on the landing.

A delta wing has

• a lower stall angle than a straight wing.
• a higher stall angle than a straight wing.
• the same stall angle than a straight wing.