Well, Paul isn't tooting his own horn with the experimentation he's
done, but I can attest to how well the extractor works that he has
built. He built a prototype for my ASW-20 that replaces the control
hookup hatch. The difference is incredible. I am able to fly with
the side window vents closed most of the time now, even when it's
pretty hot and we aren't getting that high. Not that heat has been a
problem for the last month or so. The whistling and air noise is so
significantly reduced that I found myself initially thermalling at 5+
knots higher airspeed than before, just because of the reduced audio
feedback. It took a bit to recalibrate to the reduced noise.

It's good enough that I was already considering modifying my Duo.
Especially if you live somewhere hot, the comfort is well worth it
regardless of if the performance impacts.

Morgan