High Lift Devices

Question 1

High lift devices

Answer 1

Produce Higher CL
●Same Lift At Slower Airspeed

Increase CL
●Increase Camber
●Increase Thickness
Change Planform Area

Question 2

Flaps

Answer 2

A movable portion of an airfoil which is deflected through some angle from the original chord to yield a higher camber.
Change Effective Chordline
Types: plain, split, slotted, fowler

Question 3

Flap management during takeoff

Answer 3

●First 50% Deflection
Large Increase in Lift
Small Increase in Drag
●Higher CL At Lower Airspeed
Lower Rotation Speed
Shorter Takeoff Roll
●Retraction After Takeoff
Loss of Lift
●Accelerate to Increase Lift
●Increase Angle of Attack
Pitching Moment
●Pitches Nose up

Question 4

Flap management landing

Answer 4

●Last 50% Deflection
Small Additional Increase in Lift
Large Additional Increase in Drag
●Higher CL At Lower Airspeed
Lower Approach Speed
Shorter Landing Roll
●Higher Drag At Lower Airspeed
Steeper Descent Angle
Need For Power
●Extension on Approach
Increase in Lift
●Slow
●Decrease Angle of Attack
Pitching Moment
●Pitches Nose Down

Question 5

Design considerations

Answer 5

TWISTING MOMENT
LENGTH OF FLAP
NOT AS EFFECTIVE ON THIN OR SWEPT WINGS

Question 6

Energy adders

Answer 6

Slots
Slats
Vortex Generators
BLC

Question 7

Slots

Answer 7

●pathway through the wing which allows air to flow from the lower surface to the upper surface at high angles of attack.
●High Pressure Air
Lower Surface to Upper Surface
Energizes Boundary Layer
Delays Separation At High
●No Pitch Moment
●Low Drag At Low

Question 8

Slats

Answer 8

●leading edge section that extends at high angles of attack
●changes curvature of leading edge
●adds energy to boundary layer
●High Pressure Air
Lower Surface to Upper Surface
Energizes Boundary Layer
Delays Separation At High
●No Pitch Moment
●No Drag At Low

Question 9

Vortex generators

Answer 9

small wing-like surfaces that project vertically into the airstream.
●Replaces Slower Laminar Flow With Faster Turbulent Flow

Question 10

Boundary layer control

Answer 10

●Replaces Slower Laminar Flow With Faster Turbulent Flow
Droops, hoerner tips, wing fences, spoilers.