Movement of the center of pressure:

1. Movement of the center of pressure: the peak suction pressure moves further and further forwards on the upper surface until the stall angle is approached. This must then also mean that the centre of pressure moves forwards with increasing angle of attack.

2. Finite Wing Effect (downwash – induced drag)

3. Lift Distribution

4. Lift Distribution (page 2)

5. Critical Mach number and Cdo

6. Sweep Wing Effect

7. Sweep Wing Effect Page 2 Sweep Wing Effect

8. Twist Thickness to chord

9. Ground Effect

10. Correct Physical Explanation of Origin of Lift A more fundamentally correct explanation for the origin of aerodynamic lift may be found by making use of the conservation laws of physics, namely mass flow (continuity) and energy (Euler or Bernoulli). Consider the 2-D stream tubes A and B shown in Fig 1 - these are originally of the same width when well upstream of the aerofoil and out of its influence. The common streamline between them is aligned with the leading edge stagnation point so acts to divide the airflow over the top and bottom surfaces. The stream tube A encounters the upper portion of the aerofoil and is "squashed" through what is effectively a smaller area. Stream tube B is squashed less resulting in a larger stream tube width relative to A. From continuity (dm/dt = ρ A V) this must mean that the velocity in A must be greater than in B. Either Euler's (dp = - ρ VdV) or Bernoulli's (p + ½ ρ V2 = constant) theorems may now be applied to show that pA must be less than pB. This results in the pressure distribution shown in Fig 2. It can be seen that the majority of lift is due to the low pressure (suction) acting over the upper surface, particularly over the front 20% to 30%, where the flow accelerations are at their most severe.