("Jim" wrote)
Does anybody know the shape of the connection where the left and right
sides join before exiting the outlet? "T"? "Y"?

What happens if you put some duct tape over the outlet opening on the
bottom of the plane?


How about using both setting on a shop-vac? ...and some ribbon?

Since work has recently been done, I suspect a disconnected duct piece
somewhere.


Montblack
http://www.aem.umn.edu/outreach/Baseball_Launcher/startrib1.pdf
The HHH Metrodome's vents work just fine. g

http://sportsillustrated.cnn.com/baseball/news/2003/07/26/metrodome_winds_ap/
Same air vent story