Greg,

I think the major effect on air exiting at the tail would be the total
area of tail vent. My LS8 tail has a lot of vent area (can't measure
it right now, but it's got to be 4 times the area of the inlet at the
nose). Even at that size, the interior diameter of the tail cone at
its narrowest has a much bigger area.

As for Boermans' graph, it's the total pressure around a "rotationally
symmetric body". I really have no idea from this graph what the
pressure is on the top or bottom of the fuselage, but somewhere (can't
find it now when I want it) I've seen a 3D colored pressure
distribution on a sailplane fuselage that clearly showed the pressure.
Unfortunately, I can't say where it showed the least pressure
appearing.

-John

On Dec 7, 11:52 am, Greg Arnold wrote:
Isn't there a lot of drag in a long, narrow tail boom that will restrict
the amount of air flowing to the tail? Also, how big of an exhaust
outlet can you put back there?

Also, I don't think the Boersmans graph shows pressure on the top of the
fuselage, where these outlets are located.