8. Basic aerodynamics - Q&A

An undercarriage leg in flight produces 3 lbs of drag at 100kts. If speed is increased to 200kts the drag would be

• 12 lbs.
• 9 lbs.
• 6 lbs.

Supersonic air passing through a divergent duct causes the

• pressure to increase, velocity to increase.
• pressure to increase, velocity to decrease.
• pressure to decrease, velocity to increase.

On a very humid day, an aircraft taking off would require

• a shorter take off distance.
• a longer take off run.
• humidity has no measurable effect on take off run length.

Which of the following types of drag increases as the aircraft gains altitude?

• Interference drag.
• Parasite drag.
• Induced drag.

Lateral stability is about the

• longitudinal axis.
• normal axis.
• vertical axis.

Mach number is

• the ratio of the aircrafts TAS to the speed of sound at the same atmospheric conditions.
• the ratio of the aircrafts IAS to the speed of sound at the same atmospheric conditions.
• the ratio of the aircrafts TAS to the speed of sound at sea level.

A balance tab

• effectively increases the total area of the control surface.
• assists the pilot to move the controls.
• is used to trim the aircraft about the appropriate axis.

With the flaps lowered, the stalling speed will

• increase.
• decrease.
• not change.

An aircraft flying in "ground effect" will produce

• more lift than a similar aircraft outside of ground effect.
• less lift than a similar aircraft outside of ground effect.
• the same lift as a similar aircraft outside of ground effect.

Which wing increases drag when the ailerons are moved?

• Both wings increase drag but the wing with the up-going aileron has more.
• Both wings experience an equal increase in drag.
• Both wings increase drag but the wing with the down-going aileron increases more.

An aircraft will have

• less gliding distance with a higher payload.
• more gliding distance with a higher payload.
• the same gliding distance if it has more payload.

Aspect ratio is given by the formula:

• Mean Chord / Span.
• Span^2 / Area.
• Span^2 / Mean Chord.

On a swept wing aircraft if both wing tip sections lose lift simultaneously the aircraft will

• yaw uncontrollably.
• pitch nose up.
• pitch nose down.

An aspect ratio of 8 would mean

• span 64, mean chord 8.
• mean chord 64 , span 8.
• span squared 64 ,chord 8.

The vertical fin of a single engined aircraft is

• parallel with both the longitudinal axis and vertical axis.
• parallel with the longitudinal axis but not the vertical axis.
• parallel with the vertical axis but not the longitudinal axis.

During a turn, the stalling angle

• increases with bank angle.
• decreases noticeably.
• remains the same.

Which wing increases drag when the ailerons are moved?

• Both wings increase drag but the wing with the up-going aileron has more.
• Both wings experience an equal increase in drag.
• Both wings increase drag but the wing with the down-going aileron increases more.

Induced drag

• is equal to the profile drag at Vmd.
• is equal to the profile drag at the stalling speed.
• is never equal to the profile drag.

When the trailing edge flaps are lowered, the aircraft will

• pitch nose up.
• pitch nose down.
• yaw to one side.

Aspect ratio is given by the formula:

• Mean Chord / Span.
• Span^2 / Area.
• Span^2 / Mean Chord.

For a given IAS an increase in altitude will result in

• an increase in induced drag.
• no change in the induced drag value.
• an increase in profile drag.

On a very hot day with ambient temperature higher than ISA, the pressure altitude is 20,000 ft. How much will the density altitude be?

• exactly 20,000ft.
• greater than 20,000ft.
• less than 20,000ft.

Weight is equal to

• mass * acceleration.
• mass * gravity.
• volume * gravity.

When the weight of an aircraft increases, the minimum drag speed

• decreases.
• increases.
• is unaffected.

Low wing loading

• increases stalling speed, landing speed and the landing run.
• increases lift, stalling speed and overall maneuverability.
• decreases stalling speed, landing speed and landing run.