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On the Lancair 235-360 the flaps can be moved up above the
wing as well as below. This effectively changes the camber of the airfoil to
move the point of minimum drag coefficient, the so-called "drag-bucket", to
coincide with the angle-of-attack for the required lift-coefficient based on TAS
and weight. The NLF1 0215F airfoil used on
these models had a lot of camber and so this reflex gave a way to reduce the
camber by moving the flaps up and so reducing the drag. Otherwise the wing would
have had to be flown with the wing at a negative angle-of-attack at a higher
drag coefficient. This effect of camber-changing by means of the flap can be
seen by looking at the bugs on the leading edge of your wing. When you land
and have the flaps down, the wing must fly at an apparently lower A-O-A.
Generally most airports have a field just before the approach end of the runway.
As you come in over this field, the bugs in the field, which are ardent
environmentalists, sacrifice their existence by flying up into your path
hoping to cause you to crash. Since your wing is flying nose-down relative to
your flight path, these little critters impact your wing slightly above the
leading edge at a point referred to as the stagnation point, which is
perpendicular to your flight path. Sorry! This is probably more info than you
really wanted!
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