4 Questions What effect does a Trailing Edge Flap have on the Stalling Speed?Higher.Lower.c. The same.d. No difference.
5 Questions One type of Leading Edge Flap is: Plain. Slot. c. Split. d. Krueger.
6 Questions What are some of the High Lift Devices on the Leading Edge called?a. Plain Flaps.b. Ailerons.c. Slats.d. Split Flaps.
7 Stalling Objectives: Describe the Stall in terms of Lift. State the generally used Critical or StallAngle of Attack.Understand the relationship between Stalling andAirspeed.State where the Pilot obtains information regarding theAircraft’s Stalling Speed.5. List the Factors which affect the Stalling Speed.
8 What has Stalling got to do with these? It is ESSENTIAL that a Pilot understands Stalling.During Take-Off and Landing, the Aircraft is atLow Speed.In Aerobatics the Aircraft experiences High “G”.What has Stalling got to dowith these?
9 Stalling Lift = CLMAX½ρV2MINS Lift = CL½ ρV2S Remember the Lift Formula?Lift = CL½ ρV2SIf we slow down (reduce V) we must keep Lift thesame (for Straight & Level Flight) by increasing CL.The Limit is CLMAX, so the Equivalent speed isVMIN (stalling speed)Cl MaxLift = CLMAX½ρV2MINSαCrit AOA ~ 15o
10 Stalling Speed Is: The speed at which a clean aircraft (flaps up), At a stated weight,With the throttle closed,Flying straight and level,Can no longer maintain height.
22 V STALL HVY = V STALL BASIC X EFFECT OF ‘G’LIFT HEAVYLIFT BASICV STALL HVY = V STALL BASIC XSAME FOR PULLING “g”V STALL MAN’VRE = V STALL BASIC X “g”e.g. Vstall basic = 90kts, 4g loopV STALL MAN’VRE = 90 x = 90 x 2= 180kts
23 EFFECT OF ‘G’ Danger If you pull ‘g’, the stalling speed increases, e.g. if you pull 4g the stalling speed doubles!
25 EFFECT OF THRUST ON STALLING LiftThrustFlight PathWeight
26 EFFECT OF THRUST ON STALLING LiftLiftTRThrustFlight PathWeight
27 EFFECT OF THRUST ON STALLING FLIGHT PATHAircraft in level flight have a high nose attitude at the stall,particularly swept wing aircraft.If the engine is at high power - two thrust components:1. Along flight path (countering drag).2. Vertical (opposing weight).Therefore less lift required from wings, so:SLOWER STALLING SPEED (V) AT CLMAX
35 EFFECT OF FLAP Basic ‘Clean’ Situation Chord α Relative Airflow LIFT AUGMENTATION DEVICESHow does each inc cCl , camber etc?αRelative Airflow
36 EFFECT OF FLAP Basic ‘Clean’ Situation Flap Lowered Chord α LIFT AUGMENTATION DEVICESHow does each inc cCl , camber etc?αRelative AirflowEffective Increase in AoA
37 EFFECT OF FLAP Flap Lowered Maintaining the Same Lift α LIFT AUGMENTATION DEVICESHow does each inc cCl , camber etc?αTo obtain the same CL the Attitude is Loweredto Reduce the AoAEffective Increase in AoA
38 EFFECT OF FLAP CL Cl Max Without Flap Critical Angle AoA AT STALL: WEIGHT = LIFT = CLMAX ½ρ V2STALL S
39 EFFECT OF FLAP CL With Flap Cl Max Without Flap Nose lower at Stall Cl Max MoreWith FlapCl MaxWithout FlapCLNoseloweratStallCritical AngleAoAAT STALL: WEIGHT = LIFT = CLMAX ½ρ V2STALL SIF THIS ISTHIS ISCONSTANTMORELESS
41 STANDARD STALL RECOVERY Move stick Centrally forward until buffet stops.Open throttle at the same time.Only then level the wings.Raise nose at a safe speed and climb.
42 Other Factors Affecting Stalling Ice:Alters the ‘Shape’ of the wing, this will reduce Lift.Damage:Can also reduce Lift ie after a ‘Birdstrike’.
43 Summary of Stalling Speeds What happens to the Stalling Speed if:Aircraft Weight Increases:Increase.If we Lower Flap:Decrease.If we are “Pulling G”:If the Aircraft is damaged or had a Birdstrike, it willprobably:Using Engine Thrust:
44 Stalling REMEMBER: An Aircraft can STALL in any Attitude, level, turning, upside-down etc.Where would we find our Stalling Speeds?Pilot’s Notes/Aircrew Manual etc.
46 Stalling Objectives: Describe the Stall in terms of Lift. State the generally used Critical or StallAngle of Attack.Understand the relationship between Stalling andAirspeed.State where the Pilot obtains information regarding theAircraft’s Stalling Speed.5. List the Factors which affect the Stalling Speed.
47 Questions What happens to Lift when a Wing is Stalled? Lift Increases as Angle of Attack Decreases.Lift Decreases as Angle of Attack Increases.Lift is Greatly Reduced.Lift Remains unchanged.
48 Questions The Critical Angle of Attack is Generally about? 5o. 15o.
49 Questions Which of the following will NOT REDUCE the Stalling Speed? Extra Weight.Larger Wing Area.Flaps Lowered.Flaps Raised.
50 Questions Where would you find the information regarding the Aircraft’s various Stalling Speeds?Pilot’s Notes.Air Traffic Control.Ground Crew.McDonald’s.