Aeronautics and astronautics – Aircraft – heavier-than-air – Airplane sustained
Reexamination Certificate
2000-01-31
2002-04-09
Barefoot, Galen L. (Department: 3644)
Aeronautics and astronautics
Aircraft, heavier-than-air
Airplane sustained
C244S04500R, C244S055000
Reexamination Certificate
active
06367738
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved aerobatic aircraft which utilizes two engines, where one engine is located in the nose portion of the fuselage and the second engine is located in the tail portion of the fuselage.
BACKGROUND OF THE INVENTION
Conventional aerobatic aircraft utilize a variety of aircraft designs and engine designs. For example, aerobatic aircraft designed by Curtis Pitts are single engine, biwing aircraft using tube/fabric construction. The Beech T 34A Mentor is a single engine, low wing, all metal, monoplane. The Decathlons are tube/fabric aircraft with strut-braced high wings. The Russian YAK-52 utilizes a single radial piston engine. Although these prior art aerobatic aircraft utilize a variety of wing designs, engine designs, and construction techniques, they all utilize a single engine.
A critical parameter in the performance of an aerobatic aircraft is its power to weight ratio. In order to perform vertical aerobatic maneuvers, an acrobatic aircraft necessarily needs to have available a large amount of power. An aircraft engine's power output increases as the number of cylinders and the size of those cylinders increase. A practical limit is reached, however, because an incremental percentage increase in engine power requires a greater incremental percentage increase in the engine's weight. Thus, increasing an acrobatic aircraft's power by using a larger engine results in a decreased power loading, i.e. horsepower per pound.
It is known in the art to use power from a turbine engines drive to turn a propeller. Although these “turboprop” combinations can achieve greater horsepower for a given weight than can piston engines, these turboprop powerplants do not fare well in aerobatic aircraft use. Such aircraft have acceptable vertical flight capabilities. However, such powerplants give unacceptable snap maneuvers due to their circular engine mounts.
What is needed is an aerobatic aircraft having increased power but a reduced power loading. Such an improved acrobatic aircraft would have both enhanced vertical maneuver capability and enhanced snap maneuver capability. Unlike prior art aerobatic aircraft, Applicant's invention utilizes a twin engine design with the first engine located in the nose portion of the aircraft's fuselage and the second engine located in the tail portion of the fuselage. Using this configuration, greater horsepower is available without sacrificing aircraft aerobatic performance.
SUMMARY OF THE INVENTION
Applicants' novel invention comprises an improved aerobatic aircraft design which utilizes two engines. A first engine is disposed with the nose portion of the fuselage and a second engine is disposed within the tail portion of that fuselage. Each engine has sufficient power to safely allow the aircraft to takeoff, maintain altitude, and land. Therefore, even if one engine were to fail during takeoff, Applicant's aerobatic aircraft would have sufficient power to continue that takeoff, safely navigate the traffic pattern, and safely land.
In addition, the thrust components of the two engines are coaxial along the long axis of the fuselage. Therefore, in the unlikely event one engine fails in flight, there is no change in the direction of the resulting thrust vector. Thus, even if an engine were to fail during an aerobatic maneuver, the pilot could safely complete that aerobatic maneuver, and then safely return to an airport and safely land. Applicant's invention further includes an oil system which operates in any aircraft orientation, i.e. upright, inverted, or vertical. This oil system uses two oil pumps which receive oil from opposite sides of the engines.
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The AOPA Pilot, “Stay twin proficient and still have time to swing”, May 1970, 1 page.
Barefoot Galen L.
Hayes, Soloway, Hennessey, Grossmann & Hage, P.C.
Regelman Dale F.
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