Kite AOA vs. Lift Diagrams

[ricki]

This was just put up on Kiteforum at:

Originally Posted by Hansen Aerosports

Whoa:
The bridle does two things:
1) Supports the kite shape to prevent distortion under load.
2) Allows the kite to 'de-power' by reducing the AOA (angle of attack or sheeting angle)
when you push the bar out.



The kite's lift is according to the Aerodynamic Lift equation and is proportional to the air density, wind velocity squared, the kite's area, and the Coefficient of lift Cl.



Aerodynamic Force Equation. The Coefficient of Lift is proportional to the AOA


Cl vs AOA

Example:
Wind is 15 and gusts to 21.
You are sheeted at +5˚ before the gust hits
The lift nearly doubles in the gust due to the velocity squared portion of the lift equation
You sheet out 5˚and reduce the AOA to 0˚ in the gust
The coefficient of lift drops from 1.0 to 0.5
The lift drops back to where it was before the gust hit.
Cheers!
- Bill Hansen

http://www.kiteforum.com/viewtopic.php?f=1&t=2370763