Stalling Mass Brief
Aim
• To discover the aerodynamic principles and
factors of a stall. Considering the approach
to a stall, recognition of the symptoms, and
how to recover with minimum height loss in
varying configurations.
Application
– High AoA / Low IAS Operations
– Take-off and landing
– Inadvertent stall recovery
Overview
• Aim
• Revision
• Definitions
• Principles
– Stalling
• Considerations
• Air Exercise
• Airmanship
• Review
Revision
• Aerofoil and Lift
Airspeed
Lift
Revision
Drag
Induced Drag
Parasite drag
TOTAL DRAG
Slow Fast
DRAG
AIRSPEED
Minimum Drag
Best L/D Ratio
Revision
• Lift distribution
Pressure distribution
Centre of pressure
Aerodynamic Force
+
_
≡
Definitions
• Critical angle
AoA
CL
16º
Definitions
• Stall
– Occurs when the AoA exceeds the critical angle
• Stall speed (VS)
– In following configuration: MTOW @ MSL,
Idle power, straight and level altitude, most
forward CG position, clean configuration.
Definitions
• Streamline/Laminar
Airflow
• Turbulent Airflow
• Separation Point
• Boundary Layer
• Transition Region
• Stagnation Point
Definitions
• Load Factor
Weight
Load Factor Lift
cosAngle of Bank
Load Factor 1
Principles
CL
CL
CL
CL
L
L L L
W W W W
110kt
4o
70kt
8o
44kt
16o
<44kt
>16o
IAS
AoA
Principles
Usual Symptoms Close to stall
1. High nose attitude
2. Low IAS
3. Reduced effectiveness of controls
4. Stall Warning
5. Control Buffet
Symptom after stall
1. Nose pitch down
2. Loss of height
Considerations
• Manoeuvres
Actual Stalled Flightpath
Attempted 3G
Pullout
Planned
Flightpath
Considerations
• Manoeuvres V V LF New StallSpeed S
CosAoB
LF 1
Increased
Stall Speed
1G 2G 3G 4G
2.0
1.8
1.6
1.4
1.2
1.0
“g” load
A stall occurs at an AoA, not an IAS
Considerations
• Weight
L
L
W
W
16o 16o
40 kt 44 kt
Considerations
• Centre of Gravity
Weight
Lift
Considerations
• Ice
Considerations
• Flap
Relative Airflow
Stall with flap
Lower Nose Attitude
Stall without flap
High Nose Attitude
Considerations
• Power
Thrust
TH
TV
Considerations
• Stability in the stall
Air Exercise
• Pre-Stalling Checks
– Height sufficient to recover by 3000ft
– Hatches/Harnesses secure
– Engine Temperature & Pressures
– Location – not above a populated area
– Loose articles secure
– Lookout (360 degree turn)
Air Exercise
• Entry
– Pick a reference point ( maintain with rudder)
– Retard throttle, maintaining height
– Note the symptoms
• Stall
• Recovery
– Lower nose to horizon
– Allow speed to increase through 65KIAS, full power
– Climb out
• Wing drop recovery
– Apply opposite rudder to stop yaw and or bank
– Lower nose to unstall
– Passing 65KIAS, full power
– Climb out
Airmanship
• Inadvertent stalls should never occur
• Lookout
• Smooth co-ordinated control input
• Correct handover/takeover procedure
• Monitor engine gauges
Review
• Critical angle
• Separation point
• Boundary layer
• Load factor
• Manoeuvres
• Weight
• CoG
• Ice
• Flap
• Power
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