paul stewart wrote:
>
> Another finishing question. Whats the best thing to do with shaping
> trailing edges (ailerons, flaps etc) - squared off or rounded.
>
> I'm wondering if paint will stick better to a rounded trailing
> edge. Any thoughts?
It's not just paint adhesion, but applied paint just will not build up
at a sharp corner. Make 'em round.
There are good aerodynamic effects to a blunt trailing edge, but not at
the edge thickness here, but rather around 5% of chord - 7/16" thick for
the aileron.
Any improvement in a control surface's lift coefficient isn't
necessarily desirable either. Many years ago there was temporarily an
Airworthiness Directive on my other plane, where the beveled edge of the
aileron had to be chopped off blunt to about 3/4" thickness. To cure,
they said, an odd phenomenon where a couple planes of several thousand
experienced a slight low-period oscillation - several seconds per cycle
- only in heavy rain. When word spread as to the horrid effect on
control feel, the FAA in rare form backed down on the directive. Owners
were on the verge of surrounding FAA HQ in Washington with pitchforks
and burning torches!
Regards,
Fred F.
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