http://www.pressurethrust.com/From Aerodynamic Drag to Aerodynamic Drive
by David Birkenstock
A significant increase in fuel economy is possible from a powered aerodynamic design.
Full article in the link. Might have applications for fully faired recumbents...Pressure thrust is an aerodynamic phenomenon that, just like its better known sibling, aerodynamic lift, exploits Bernoulli's principle which relates fluid pressure and velocity. The flight and wind tunnel tests referenced below proved an over 40% reduction in total power required, including power for the suction system, against streamlined designs of comparable size.