Aileron / flap corner drag ?

tango4 writes:
Just how much drag difference do aileron
fences make given that they increase the wetted area by several square
inches themselves?

I had the fences on the root ends of the flaps of my ASW-20 until recently when
I discovered by accident that they were like little parachutes on my wings. A
discarded pee bag (yes I toss them, so what) burst on the wing LE and left
telltale dried evidence that the local airflow in the region of the flap fence
was out of alignment with the fence by about 20 degrees, most likely creating a
large vortex with more drag that the resulting little gap once the fence was
removed.
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Mark Navarre
ASW-20 OD
California, USA
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