Ch 13 - Stalling

Question 1

Low Speed Stall

Answer 1

Caused by excessive AoA

• Boundary layer separates earlier as it no longer has the energy to stay on as the adverse pressure gradient is high
• Lift can no longer keep up with demand = Lift collapse

TO recover, reduce AoA

Question 2

The Effective Airflow

Answer 2

The Aerofoil only cares about the Effective AoA

Question 3

Rectangular Wing Stalling Characteristics

Answer 3

Elliptical Lift distribution
Increased vortices at the tips
CL highest at the root

Roots stall first as they reach the critical AoA first
They provide stall warning felt as light/heavy buffet
No violent wing drop

Question 4

Elliptical Wing Stall Characteristics

Answer 4

Decreased wing tip vortices
Trailing edge vortices are consistent

Whole wing will stall together
Potential violent wing drop

Question 5

Moderately Tapered Straight Edge wing stall characteristics

Answer 5

Wing is efficient
Stalls in the middle of the wing first
Can be violent

Question 6

Swept Wing and highly tapered wing stall characteristics

Answer 6

Tips work harder than root
No stall warning
Bad wing drop
CofP moves Fwd -> Pitch up -> increased downforce from HS ->more pitching up ->unstable aircraft

Question 7

Deep Stall (Locked in Stall)

Answer 7

Horizontal stabiliser will no longer produce downwash to pitch the nose down

• Stick pusher will kick in and force aircraft nose down or to limit it rising too far
• Airbus wont allow you to get to that point