|Illustration of drag reducing aircraft fuselage|
The USDOE Office of Energy Efficiency and Renewable Energy (EERE) estimates that US aircraft consumed 1,040 thousand barrels (43.7 million gallons) of petroleum per day in 2010. This represents slightly less than eight (8) percent of the daily total transportation petroleum consumption in the country that year, and is slightly less than 25% of the daily car usage of petroleum. Still, 44 million gallons is a considerable volume, and steps to improve the fuel economy of aircraft can play a part in allowing us to more efficiently use our fossil fuel resources.
There are multiple ways of improving aircraft fuel efficiency, ranging from engine design, to flight profiles and routing (along with changes in air traffic control), to reducing the drag of the aircraft.
“System and method for drag reduction”
Claim 1 states:
A method for increasing efficiency of an object moving through a fluid, comprising the steps of:Although the USPTO considers this to be an aircraft invention, Birkenstock’s claim wording, and the patent specification and drawings, show that some embodiments can include road vehicle design. The USPTO examiners did not consider the auto sedan design aspects worthy of inclusion as cross-reference classifications, nor did they include any land vehicle classifications in their prior art searches. We include two drawings from the patent, one for an aircraft, and one for an auto sedan, showing Birkenstock’s drag reducing design concept.
- forming a convex cusp area at substantially a rear of the object;
- extending one of a suction inlet and a blowing outlet with a convex transition portion on an end of said convex cusp area;
- extending a stagnation area from an end of said blowing outlet, said stagnation area having a concave shape;
- and varying a pressure thrust on said object by varying a sharpness of the convex cusp area.
|Illustration of drag reducing auto sedan|