ORIGINAL: Tall Paul
ORIGINAL: Richard L.
ORIGINAL: dick Hanson
You can't reshape a given area and increase lift- --you CAN make the wing more controllable at a given speed - but thats it.
Flaps do that too The lift does not increase (tho drag does) but the descent angle is more controllable.
One more question: If flaps do not increase lift by reshaping a given area, then why do my planes balloon way up when I deploy them?
It's the change in Cl with the flap. The Cl with flap is higher than the Cl without flap, but it occurs at a lower angle of attack.
If the alpha isn't changed, the plane falls out of the sky.
Example... Cl near stall, about 8 degrees alpha, without flap.
A
60 degree flap the -same- Cl (the lift hasn't changed) is -5 degrees.
B.
Lowering the nose puts the wing outboard of the flap at -5 degrees
C, well below stall, and the same effect as a LOT of washout.
The reason why your plane balloons when you deploy flaps is because you don't reduce the body attitude (pitch angle, NOT the same as AOA)
L = 1/2 x Rho x V² x S x Cl
If you lower flaps, as Paul said the CL increases. As a result the total lift will increase and you will climb, this is the ballooning. The logical way to solve this is to reduce the body attitude while you extend the flaps. The opposite happens if you rectract the flaps.
Bart