The Ultra-Efficient Products Penetrater was an American ultralight aircraft designed by Nick Leighty and Rick Berstling and produced by Ultra-Efficient Products.

[1] The aircraft's most notable feature was that the pilot flew in the prone position.

[2] The pilot lay on top of the fuselage, and used elbow rests and foot stirrups.

[1] The aircraft had a cantilever low-wing, a fuselage consisting of a single aluminum alloy tube, a V-tail, a tricycle landing gear, and a single engine in pusher configuration.

Data from Jane's all the world's aircraft, 1987–88[1]General characteristics Performance