Paul,

The non-technical write-up at DG on the Mandl air extractor
experiments backs up your position ( http://www.dg-flugzeugbau.de/mandl-absaugung-e.html
). But graph 7a in Prof. Boermans' paper ( http://frotor.fs.cvut.cz/doc/37.pdf
) suggests that the tail position is on a par with the pressure in
back of the wing.

-John

On Dec 7, 11:24 am, sisu1a wrote:
An interesting gadget. However, wouldn't it be more logical to vent

nearer the rear of the fuselage, say in the lower tail?

Absolutely not... and this one of the major contributing factors to
why most glider's vent do not work. That's where designers have been
sticking them ever since Wil Shuman put one on his Libelle.

-Paul