Aeronautics and astronautics – Aircraft power plants – Mounting
Reexamination Certificate
1999-12-07
2001-10-30
Eldred, J. Woodrow (Department: 3644)
Aeronautics and astronautics
Aircraft power plants
Mounting
C244S055000, C244S120000, C244S232000, C244S198000
Reexamination Certificate
active
06308915
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to an aircraft tailcone. More particularly, the present invention relates to a detachable integral aircraft tailcone and power unit assembly configured for quick attachment to and removal from an aircraft.
BACKGROUND OF THE INVENTION
Modem turboprop and turbofan powered aircraft carry a gas turbine engine known as an auxiliary power unit (APU) in addition to the main propulsion engines. The APU serves two main functions: to provide power to aircraft systems when the main engines are not running, and to enable starting the main engines without need for external power. In many business class aircraft and in aircraft used by smaller regional airlines, the APU is mounted in the tail end of the fuselage generally known as the tailcone. Typically, the engine supplier and tailcone casing supplier coordinate with the aircraft manufacturer in the installation of the APU at the manufacturer's facility. The APU is custom fit and mounted to the aircraft, and all accessories such as electrical, pneumatic, and fuel, are routed to the APU and connected. The tailcone casing supplier then fits and installs the casing, usually including an openable or removable panel for access to portions of the APU.
A problem with this kind of APU installation is the large amount of the time and expense involved in completing an installation. The mounting of the APU and routing and connection of accessories requires substantial effort by skilled technicians and engineers from the aircraft manufacturer and APU supplier. Fitting and attaching the casing requires technical support from the tailcone casing supplier as well. A complete installation can take days or even weeks at the aircraft manufacturers facility resulting in substantial cost and inconvenience.
Another problem results from inaccessibility of the APU once the casing is in place. Typically the casing comprises two large panels that are attached to one another and to the aircraft using numerous screws. The casing includes at least one small openable door for providing access to routinely monitored items such as the oil sight glass. However, for anything beyond the routine day to day maintenance it becomes necessary to remove at least one of the large casing panels. Removal of just the screws holding the panels together can take thirty minutes or longer. The time spent on removing and reinstalling the tailcone casing can become particularly inconvenient and costly when it results in unplanned delay to scheduled flights.
Accordingly, a need exists for a system that substantially reduces the time and labor required to install and test an APU and tailcone casing onto an aircraft. Another need exists for a tailcone casing that provides quick access to the entire APU mounted therein.
SUMMARY OF THE INVENTION
In view of the above, it is an object for this invention to provide a system that substantially reduces the time and labor required to install an APU and tailcone casing onto an aircraft, and to provide a tailcone casing giving quick access to the entire APU mounted within.
The present invention achieves these objects by providing a detachable integral aircraft tailcone and power assembly mountable to the body of an aircraft using a height adjustable dolly. The tailcone assembly comprises a longitudinal support member having forward and aft axial ends; a gas turbine engine mounted within the tailcone to the support member; a firewall extending from the support member forward of the engine; two curved rotatable casings hingeably connected to the support member and rotatable from a closed position to an open position thereby exposing the engine, the open position being at least 90 degrees from the closed position; an inlet duct extending from an aperture in one of the rotatable casings to the engine inlet; and interface means for making necessary electrical, mechanical, pneumatic, and hydraulic accessory connections between said tailcone assembly and said aircraft body. The forward axial end of the support member includes a flange adapted for quickly and rigidly attaching the entire tailcone assembly to the aircraft body. The integral aircraft tailcone may also include an integrated exhaust muffler.
The tailcone assembly is installed on the aircraft by mounting the tailcone in the adjustable dolly, rolling the dolly up to the aircraft, adjusting the dolly until the tailcone assembly is properly aligned for attachment to the aircraft, connecting the engine accessories to the aircraft, and bolting the tailcone to the aircraft.
These and other objects, features and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of a preferred embodiment of the invention when read in conjunction with the accompanying drawings.
REFERENCES:
patent: 2504422 (1950-04-01), Johnson
patent: 6039287 (2000-03-01), Liston et al.
patent: 1 212 875 A (1970-11-01), None
patent: 91 08379 A (1991-06-01), None
European Search Report dated May, 23, 2000.
Liston Laurence D. N.
Schoepf Joseph L.
Allied-Signal Inc.
Desmond, Esq. Robert
Eldred J. Woodrow
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