Richard Isakson wrote...

From Perkins and Hage "Airplane Performance Stability and Control": "The
pure frise type aileron is characterized by an asymetrical sharp nose
located on the airfoil lower surface so that it will unport as soon as the
control is deflected upward."

Cool answer. P&H is setting on a bookcase right
behind me. Maybe I should've cracked it instead
of looking for a shovel :-)

Dave 'frise frame' Hyde