Hi David
"> There is the consideration that increasing the flap extension beyond
its
> stated limit might push the structural limits of the flaps. Don Dykin's
> booklet on the aerodynamics of the Europa says that at max flap speed the
> flaps support about half of the plane's weight. Could an extra 3 degrees and
> a corresponding change of the angle of the flap lift force be the straw that
> did for that particular camel?"
No matter what the absolute answer is, best to keep maximum flap extension
speed as published.
That said my partner Wayne built a model of the Europa XS in X-Plane. One
mode is you can display dynamic arrows of stress. You can not believe how
rapid the stresses on the outboard section of the wing grow when you
exceed maximum flap extension speed! It begins that with full flaps the
tip of the wing is lifting a little, then with increased speed the inboard
section of the wing is lifting so much it requires that you lower the
nose, then the outboard section of the wing now is creating negative lift
and then if you increase speed further, the stresses look downright scary!
Increasing flap angle would no doubt place greater loads as stated above.
Ron Parigoris
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