16. Basic aerodynamic theory (Lift)

Question 1

Airflow past an aerofoil such as the wing of an aeroplane can produce an …….. force.

Answer 1

Aerodynamic

Question 2

A steady flow of molecules around the aerofoil, with succeeding molecules following the same path, is called …….. flow

Answer 2

Streamline

Question 3

A disturbed flow with eddyiny is called …….. flow.

Answer 3

Turbulent

Question 4

If the velocity if the airflow over the upper surface of the wing increases, static pressure will ……..

Answer 4

Decrease

Question 5

In normal flight, the static pressure over the top surface of a well-cambered wing is (less than / greater than / the same as) the static pressure beneath the wing.

Answer 5

Less than

Question 6

The angle between the chord line of an aerofoil and the direction of the airflow well ahead of the aerofoil is called the …….. …….. ……..

Answer 6

Angle of attack

Question 7

If the angle of attack is increased gradually, the lifting ability of the wing (increases / decreases)

Answer 7

Increases

Question 8

At a critical angle of attack, known as the stalling angle, the streamline airflow breaks down and becomes turbulent and the lifting ability of the wing (increased / remains good / decreases)

Answer 8

Decreases

Question 9

If the pilot increases the angle of attack so that the lifting ability of the wing is increased the same lift force can be generated by the wing at a (higher / lower) velocity

Answer 9

Lower

Question 10

An increased airflow over an aerofoil at the same angle of attack will cause (more / less / the same) lift

Answer 10

More

Question 11

Increasing angle of attack at a constant airspeed will cause (more / less / the same) lift

Answer 11

More

Question 12

Lowering flaps has the effect of increasing the camber of a wing. This will (increase / decrease / not change) its lifting ability (CL)

Answer 12

Increase

Question 13

Lowering flaps and not lowering the nose of the aeroplane will cause (more / less / the same) lift

Answer 13

More

Question 14

With flaps lowered, the wing (can / cannot) produce the same lift at a lower airspeed.

Answer 14

Can

Question 15

A wing (has / does not have) its maximum lifting ability (CL) when the angle of attack is just at the critical angle, which is typically …….. degrees

Answer 15

Has; 16

Question 16

When a wing is taken beyond its critical angle of attack, typically…….. degrees, the airflow becomes (streamlined / turbulent), the lift force (increases / decreases) and the wing is said to have ……..

Answer 16

16; turbulent;decreases; stalled

Question 17

Ice or other contamination on a wing surface (may / will not) disturb the streamline airflow and cause a drastic reduction in lift

Answer 17

May

Question 18

The most inoortantvarea if the wing for lift production is the:

a) bottom surface
b) upper surface behind the leading edge
c) upper surface near the trailing edge

Answer 18

B