Squared trailing edge of control sufraces

A while back I remember seeing an article in one of the aviation
magazines about the affect of squared off trailing edges on control
surfaces of light planes. Anyone know where such an article might exist?
So far I have found several Boeing and NACA publications on wings with
blunt trailing edges, or blunt trailing edges at supersonic speeds. But
little specific to light planes with top speeds of 150 mph and landing
speeds of 40 mph or less.

I seem to remember that the squared off trailing edge of ailerons and
tail surfaces improved control authority, particularly at slow speeds.
Anyone have an idea?

--
Bruce A. Frank