Lift augmentation

Question 1

How do leading lift augmentation devices change the camber?

Answer 1

Increase positive Camber.

Question 2

Plain flap.

Answer 2

Extend from trailing edge and pivot downward.
Lots of drag.
Increased Cl.
Reduced critical AOA.

Question 3

Split flap.

Answer 3

Attached to underside of the wing.
Increases lift.
Significant drag.
Same Cl as plain, increased critical AOA from plain but less than clean.

Question 4

Fowler flap.

Answer 4

Slide backwards before extending down.
Increase camber and Surface area.
Increases Cl without massive drag.

Question 5

Variable camber leading edge edge flap.

Answer 5

Improvement of Kruger flap.
Move out and extend more than Kruger.
Can move out in stages.
Increase lift and critical AOA.

Question 6

Kruger flap.

Answer 6

Leading edge lift enhancement device.
Portion of the lower wing is rotated out in front of the main wing leading edge.
Increase lift and critical AOA.

Question 7

What is a slot, on an aerofoil?

Answer 7

Leading edge - spanwise gaps that allow wing to flow from below the wing to the upper surface. Enable flight at higher AOA and reduce stalling speed.

Question 8

How do slots effect the boundary layer?

Answer 8

Re-energise the boundary layer at high AOA.
Flow separation is delayed.
Higher Clmax.
Stall speed is decreased.

Question 9

How do flaps effect wing tip vortices?

Answer 9

Reduces wingtip vortices but now has some flap tip vortcies (not as strong). Done by disrupting the airflow (dirty).

Question 10

V speeds.

Answer 10

Vso -
Vfe -
Vno-
Vne -

Question 11

What setting of flaps gives the most drag with least lift?

Answer 11

First 50% gives most the lift.
Second 50% gives most the drag.