12.6.30. On a typical CL versus angle of attack curve, identify the critical stalling angle.
When the flaps are put down the effective camber of that part of the wing is increased
The effect is to increase the lifting capability of the wing as a whole
(see additional notes)
12.6.28. Describe a typical CL versus angle of attack curve (graph).
On the graph the CL and angle of attack are proportionate until the stalling range is reached at a maximum angle of attack
12.6.26. Identify the primary factors determining the coefficient of lift (CL) for an aerofoil.
The combined effect of the shape of the aerofoil and its angle of attack is represented by the CL
The higher the value of CL the greater the lifting capacity of the aerofoil
12.6.24(b) . summarise the factors affecting lift. (i.e. angle of attack, aerofoil shape, IAS)
Lift is affected by :
The shape of the aerofoil (High lift v High Speed)
The speed and direction of the airflow over the wing.
The angle of attack.
The size (plan area) of the wing.
The density of the air.
From a practical point of view, in a given aircraft lift is related to:
Angle of Attack
The shape of the aerofoil (both design and flaps etc)
Indicated Airspeed.
12.6.24(a) . State the lift formula;
Lift = Coefficient of lift x 1/2 Roe x Vsquared
12.6.24. With respect to lift:
12.6.24(a) . State the lift formula;
Lift = Coefficient of lift x 1/2 Roe x Vsquared
12.6.24(b) . summarise the factors affecting lift. (i.e. angle of attack, aerofoil shape, IAS)
Lift is affected by :
The shape of the aerofoil (High lift v High Speed)
The speed and direction of the airflow over the wing.
The angle of attack.
The size (plan area) of the wing.
The density of the air.
From a practical point of view, in a given aircraft, lift is related to:
Angle of Attack
The shape of the aerofoil (both design and flaps etc)
Indicated Airspeed.
lift formula |
factors affecting |
|---|---|
| CL – Coefficient of lift | |
| ½ | |
| ρ – Rho | |
| V² – Velocity | |
| S – Wing Area |
12.6.22. Define the Lift and Drag components of Total Reaction.
Lift:
Lift is the component of the aerodynamic force (TR) at right angles to the relative air flow
Drag:
Drag is the component of aerodynamic force (TR) parallel to the relative airflow and opposing motion
12.6.20. Show how movement of the CP varies between symmetrical and non-symmetrical aerofoils.
For non-symmetrical aerofoils the CP moves significantly with changes to angle of attack.
For symmetrical aerofoils there is little or no movement of the CP with changes to angle of attack.
12.6.18. Describe how TR and CP change with increasing angle of attack for a lifting aerofoil.
For a general purpose aerofoil as angle of attack is increased the TR will increase and incline more rearwards.The CP will move forward progressively until the stall angle is reached. At this point it will move rearwards.
For a symetrical aerofoil the TR will increase and incline more rearwards, but the CP will not move. (image)
12.6.16(b) . centre of pressure (CP).
CP:
The centre of pressure is the point in the aerofoil which the total reaction (TR) is acting through.