Lift Augmentation

Question 1

What are the four types of leading-edge devices?

Answer 1

• Slots
• Slats
• Drooping leading edge
• Kruger Flap

Question 2

What is the purpose of leading edge devices?

Answer 2

They increase the stall angle of the aerofoil/aircraft allowing better flight characteristics for landing/takeoff

Question 3

What is a ‘slot’?

Answer 3

A mechanism built into the aerofoil and channels high-pressure stagnation air under the leading edge back to the upper surface, re-energising the sluggish boundary layer

Question 4

What is a ‘slat’?

Answer 4

A slat or ‘moveable slot’ is a movable extension to the leading edge of the aerofoil which creates a slot when extended.

Question 5

What is the purpose of flaps?

Answer 5

• Increase lift at slow speeds

- Increase lift and drag during landing

Question 6

How does a fowler flap increase lift?

Answer 6

• Increases camber
• Increases alpha at the same attitude
• Increases surface area
• Energise the boundary layer if slotted

Question 7

What is the most effective combination of leading and trailing edge devices?

Answer 7

Slats and triple slotted fowler flaps

Question 8

What is the purpose of vortex generators?

Answer 8

Add energy to the boundary layer by creating small, energised turbulence/vortices at a thin level, allowing the overall flow of laminar flow to be improved over the aerofoil surface; also extends the TP back allowing:

• Increases lift
• Decreases drag

Question 9

What are 4 methods of boundary layer control?

Answer 9

• Suction
• Blowing
• Vortex Generators
• Air Jets