Good points Harry , Might I also add that the effect, drag wise, on raising trailing edges varies dependent on aerofoil section, symmetrical, semi-symm or a type such as a glider section with under camber at the aft part. Think proof of this can be easily seen by the fact that many high performance sailplanes can use a litte negative flap to achieve greater range at higher speed suggesting that l/d ratio which defines distance from height is improved and as lift is constant the drag must have been reduced.

Angle of upset may also be significant with perhaps some reduction in drag at small angles but followed by a rapid increase as angle increases. Every wing section will vary.

As an aside it was interesting to note that the Mig 27s at the JWM BOTH employed aileron DROOP (or at least the ouboard wing section as it probably uses tailerons for roll control) wiith the TE and LE flaps extended and the wings swept forward. No signs of tip stall there.

And if anyone STILL thinks that aileron upset lowers stalling speed take a look at all the airliners landing with upset ailerons at an airport near you . My guess is ZERO ! (but the flaps will all be DOWN )

Great to see a healthy and productive debate on RCU.

Regards,

David.