I see more and more planes getting significant speed increases by setting the flaps in a negative 3-6 degree setting. Has anyone done this for a certified airplane?
yes,
but it is a little difficult to do with the cessna due to the design of the flap and its relation with the wing. I have more success with adjusting the wings to make sure the trailing edge of the wing on both sides is as high as possible with the airplane flying straight. sometimes that isnt possible due to either damage history/repairs or simply that the airplane was originally built crooked.
By setting the flap in negative,we can reduce the normal drag to some extent.Ultimately the speed will increase by this action,and the same force of lift will get under the wings of the aircraft.But the setting should be done according to the airfoil design of the aircraft which is designed accordingly to the thrust& speed of the craft.
