Stalling Mass Brief Aim • To discover the principles and factors of an aerodynamic stall. • Considering the approach to a stall, recognition of the symptoms. • how to recover with minimum height loss in varying configurations. Application – High AoA / Low IAS Operations – Take-off and landing – Sharp climb, descent, turns – How to recover from a stall Overview • Aim • Revision • Definitions • Principles – Stalling • Considerations – Manoeuvres – Weight – Ice – Flap – Stability – Power – Ailerons • Air Exercise • Airmanship • Review Revision • Aerofoil Revision • Lift formula: Airspeed Lift ρV S 2 Lift C 1 2 L Angle of Attack Camber Airspeed Wing surface area Definitions • Critical angle AoA CL 16º Definitions • Stall (Aerodynamic Stall) – Occurs when the AoA exceeds the critical angle – The wing then doesn’t produce enough lift to support the weight of the aircraft • Stall speed (VS orVS1) – In following configuration: MTOW @ MSL, Idle power, straight, level altitude, most forward CG position, clean configuration. • Stall speed (VS0) – Same as above but in landing configuration (Full flaps) • However a Stall is only dependant on the AoA, we can stall at any IAS Definitions • Load Factor – “G Force” – “G Loading” Weight Load Factor Lift cosAngle of Bank Load Factor 1 Definitions • Separation Point • Turbulent Airflow • Transition Point • Transition Region • Boundary Layer • Stagnation Point • Streamline/Laminar Airflow Principles CL CL CL CL L L L L W W W W 110kt 4o 70kt 8o 44kt 16o <44kt >16o IAS AoA Principles TP SP L 4 >16 16 8 CG CP Nose pitch down Principles Usual Symptoms Close to the stall 1. High nose attitude 2. Low IAS 3. Reduced effectiveness of controls 4. Stall Warning 5. Control Buffet Consequences of a stall 1. Loss of height 2. Nose Pitch Down Considerations • Manoeuvres Actual Stalled Flight path Attempted 3G Pullout Planned Flight path 70 KIAS >16º Considerations • Manoeuvres CosAoB LF 1 V V LF New StallSpeed S A stall occurs at an AoA, can occur at any IAS Considerations V 44 1.73 New StallSpeed Actual Stalled Flightpath Attempted 3G Pullout Planned Flightpath V V LF New StallSpeed S S V V 76.21KIAS New Stall Speed 70 KIAS V 44 3 New Stall Speed 44 KIAS Considerations • 60 degree angle of bank CosAoB LF 1 Cos60 LF 1 2 0.5 LF 1 V V LF New StallSpeed S V 44 2 New Stall Speed V 44 1.41 New StallSpeed V 62.23 KIAS New Stall Speed Considerations • Weight L L W W 16o 16o 44 kt 55 kt Considerations • Centre of Gravity Weight Lift Considerations • Centre of Gravity Weight Lift Considerations • Ice • Frost Considerations • Flap Relative Airflow Stall with flap Lower Nose Attitude 33 KIAS Stall without flap High Nose Attitude 44 KIAS 16º 16º Considerations • Stability in the stall Considerations • Power Thrust TH TV Considerations • Wing drop / Ailerons Considerations • Ailerons Summary Increase Decrease • Manoeuvres • Weight • Centre of Gravity • Ice • Stability • Flap • Power • Ailerons Air Exercise • Pre Entry – Lookout – Pick reference point – Manoeuvre checks: – H – H – E – L – L – L eight sufficient to recover by 3000ft AGL! atches/Harnesses secure ngine Temperature & Pressures ocation – not above a populated area oose articles secure ookout (360 degree turn) Air Exercise • Entry – Pick a reference point – Retard throttle, maintaining height (Keep straight with rudder) – Note the symptoms • Stall • Recovery – (Release back pressure) Lower nose to descending attitude – Allow speed to increase through 65KIAS, full power – Ease into the climb • Wing drop recovery – Keep aileron neutral – Apply full opposite rudder to stop yaw and or bank – (Release back pressure) Lower nose to unstall – Once unstalled, Centralise the rudder, full power (Keep straight with rudder) – Ease into the climb Airmanship • Accidental 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 • C.G. • Ice • Flap • Power作者: cdzfk 时间: 2010-9-21 09:44:30