Chapter 16: Lift Augmentation

Question 1

TE Flap Types

Answer 1

Plain Flap
Split Flap
Slot
Fowler

Question 2

Plain TE Flap

Clmax, AoAs, CP

Answer 2

+ Clmax (camber)
- AoAs (rounder wing)
CP aft (homogeneous L distribution)

Question 3

Split TE Flap
Clmax, AoAs, Drag
Why is 3rd element good (2)

Answer 3

\+ Clmax (camber)
- AoAs (less AoAs loss than plain because wing top not deformed
High drag penalty -> high thrust
= Vs increase
and = reactive engines

Question 4

TE Slot
AoAs
TE Fowler
Clmax, Surface, AoAs

Answer 4

Slot:
\+ AoAs (reenergises flow)
Fowler:
\+ Clmax (camber)
\+ Surface
\+ AoAs

Question 5

LE Flap Types (4)

Answer 5

Plain LE Flap
Krueger LE Flap
Slot
Slat

Question 6

Plain LE Flap

AoAs, Clmax

Answer 6

+ AoAs (increases LE radius -> less energy loss)

+ Clmax (camber)

Question 7

Slot

AoAs, Clmax

Answer 7

+ AoAs (reenergises flow)

-> + Clmax

Question 8

Krueger LE Flap

What is it, where to put for sweptback wings

Answer 8

Plain LE Flap with hook (if stag. point below Krueger flap -> stall)
Sweptback wing = root

Question 9

LE Flap or Slat

Answer 9

LE Slot + LE Plain Flap

Question 10

Plain, Splitted, Slotted, Fowler
In Order of Drag
In Order of Clmax

Answer 10

Drag (+ to -) : split, plain, slotted, fowler

Clmax (+ to -) : fowler, slotted, split, plain

Question 11

Flaps at root and vortices

Answer 11

Flaps @ root = less L at tip = less tip vortices

Question 12

Flaps and Pitch (2)

Answer 12

Cp aft -> pitch down

root downwash -> more elevator downforce -> pitch up (tailplane effect)

Question 13

Lift Renergizing Devices (3)

Answer 13

Vortex generators (turbulent air ailerons)
Strakes (sharp symmetric airfoils on AC)
Chines (on engine)

Question 14

TO Flap
What do when retract flaps
Effect of Flap on Cl Cd

Answer 14

Flap retract = pitch up for L constant
50% flap - high increase Cl, small increase Cd
100% flap - low increase Cl, high increase Cd

Question 15

Flap Asymmetry

Which is worse, LE Flaps or TE Flaps? How to prevent

Answer 15

Flap worse -> for same AoA, higher Cl increase
Longer landing
Flap asymmetry sensor

Question 16

Flap Setting

Action when Flap Retraction? Flap Settings Affect Cl/Cd? Why Landing Full Flaps (2)?

Answer 16

Retract: pitch up to maintain L
50%: large inc Cl, small inc Cd
100%: small inc Cl, large inc Cd
Good at landing -> low Vs, high T

Question 17

Abnormal Flap Operation

Consequences at TO, Land?

Answer 17

Land -> longer landing, Vs higher

TO -> endurance, range decrease