Aeronautics and astronautics – Aircraft power plants – Transmission of power
Reexamination Certificate
2000-06-28
2002-10-22
Eldred, J. Woodrow (Department: 3644)
Aeronautics and astronautics
Aircraft power plants
Transmission of power
C244S006000, C244S012300, C244S02300R, C180S337000, C074S6650GB, C074S423000
Reexamination Certificate
active
06467726
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vertical takeoff and landing aircraft or a short takeoff and landing aircraft (hereinafter referred to as a V/STOL aircraft as well) and to a torque transmission. The present invention may be favorably applied to an aircraft which uses bi-blade rotors and bi-blade variable pitch propellers.
2. Description of the Prior Art
(a) As regards prior art V/STOL aircraft, prototypes of a number of tilt rotor aircraft have been manufactured since the 1950s. Typically, in the case of such an aircraft, wings equipped with propellers and engines is tilted with respect to the fuselage, or propellers equipped with engines are tilted, to direct the thrust upward, thereby performing vertical takeoff and landing similarly to helicopters. In the case of a prior art tilt rotor aircraft as mentioned above, flight is performed such that propellers equipped with engines are turned upward when a vertical takeoff or a vertical landing is made (in the helicopter mode) and propellers equipped with engines are turned forward when a level flight is made (in the fixed aircraft mode). The time required for the transition from the helicopter mode to the fixed wing mode or the other way around is more than ten-odd seconds, thus causing a problem in that the aircraft becomes very unstable during the transition.
(b) Prior art torque transmissions for VTOL aircraft serve to transmit engine output to propellers or rotors, but do not serve to transmit engine output simultaneously to propellers and rotors.
Propellers and rotors are prerequisites for realizing a VTOL aircraft capable of safely and easily switching from the helicopter mode to the fixed wing mode, as well as from the fixed wing mode to the helicopter mode.
For this purpose, it is necessary to have a simple torque transmission capable of transmitting engine output simultaneously to propellers and rotors. However, prior art torque transmissions cannot transmit engine output simultaneously to propellers and rotors.
DEFINITIONS OF TERMS
(a) “Helicopter mode”
The helicopter mode is defined as a flight mode wherein an aircraft stays aloft by means of only the lift of rotors (i.e. the resultant of the lifts produced by rotors), with the lift of fixed wings equal to zero.
(b) “Fixed wing mode”
The fixed wing mode is defined as a flight mode wherein an aircraft flies by means of only the lift produced by fixed wings, with the lift of rotors equal to zero.
(c) “Compound mode”
The compound mode is defined as a flight mode wherein an aircraft flies by using the lift produced by rotors and the lift produced by fixed wings.
(d) “Rotor and rotor lift”
A rotor is defined as a member comprising:
a plurality of rotor blades producing a lift during rotation;
a rotor shaft supporting the above-mentioned rotor blades; and
a rotor lift is defined as the resultant of the lifts produced by a plurality of rotor blades.
OBJECT OF THE PRESENT INVENTION
The object of the present invention is, in view of the above-mentioned circumstances, to provide an aircraft and a torque transmission which are capable of resolving the problems stated in items (a) through (d) below.
(a) An aircraft which is capable of flying in the compound mode, wherein rotors and fixed wings produce a lift, in the helicopter mode, wherein only rotors produces a lift, and in the fixed wing mode, wherein only fixed wings produce a lift, shall be provided.
(b) An aircraft which has satisfactory stability and controllability both in the helicopter mode and in the fixed wing mode shall be provided.
(c) An aircraft which does not become unstable during transition either from the helicopter mode to the fixed wing mode or from the fixed wing mode to the helicopter mode shall be provided.
(d) A torque transmission, a bi-blade rotor, and a bi-blade propeller all of which may be favorably used on the above-mentioned aircraft shall be provided.
In the next place, the present invention, which was devised for the purpose of resolving the above-mentioned problems, is explained.
For the purpose of resolving the above-mentioned problems, an aircraft of the first aspect of the present invention comprises:
1. An aircraft comprising:
(a) an airframe having,
(1) a fuselage extending longitudinally,
(2) a set of fixed wings consisting of a main wing and a horizontal tail wing both of which are connected to the above mentioned fuselage at two locations longitudinally apart from each other and both of which extend laterally and are capable of producing lifts during forward flight, and a vertical tail wing,
(3) two ailerons one of which is installed on the right-hand section of the above mentioned main wing and the rest of which is installed in the left-hand section of the above mentioned main wing,
(4) two elevators one of which is installed on the right-hand section of the above mentioned horizontal tail wing and the rest of which is installed in the left-hand section of the above mentioned horizontal tail wing, and
(5) a rudder installed on the above mentioned vertical tail wing;
(b) a propeller-rotor torque transmission having,
(1) a shaft support coupler wherein
one end each of a propeller shaft support and a rotor shaft support both of which lie at right angles to each other,
and one end of an input shaft which lies at right angles to the above mentioned propeller shaft support and to the above mentioned rotor shaft support or which lies coaxially with either the above mentioned propeller shaft support or with the above mentioned rotor shaft support,
are coupled together in such a way as to preclude rotation,
(2) a cylindrical input shaft which is installed in such a way as to permit rotation around the above mentioned input shaft support,
(3) a cylindrical propeller shaft which is installed in such a way as to permit rotation around the above mentioned propeller shaft support and on which a variable pitch propeller for producing a propelling force is installed,
(4) a cylindrical rotor shaft which is installed in such a way as to permit rotation around the above mentioned rotor shaft support and on which is installed a rotor head that supports a rotor blade for producing a lift such that only the collective pitch is variable, and
(5) a bevel gear which transmits the rotation of the above mentioned cylindrical input shaft (hereinafter referred to as an input shaft), simultaneously to the above mentioned cylindrical propeller shaft (hereinafter referred to as a propeller shaft), and to the above mentioned cylindrical rotor shaft (hereinafter referred to as a rotor shaft):
(c) an engine gearbox which supplies the above mentioned input shaft with rotational motive power; and
(d) a flight control system having,
(1) a propeller collective pitch controller which controls the pitch angle of the above mentioned variable pitch propeller;
(2) a rotor collective pitch controller which controls the collective pitch of the above mentioned rotor blade;
(3) an engine power controller which controls the output of the above mentioned engine gearbox for the purpose of changing the rotational speed of the above mentioned input shaft; and
(4) a directional (yaw) control system which controls the deflection angles of the above mentioned ailerons and the above mentioned rudder to control the flight direction of the aircraft during forward flight.
The aircraft of the present invention may be provided with a plurality of propeller-rotor torque transmissions.
Namely, only one propeller-rotor torque transmission may be installed on the aircraft, for example, in the upper central section of the aircraft;
a total of two propeller-rotor torque transmissions may be installed on the aircraft, for example, one in the right-hand section of the aircraft and the other in the left-hand section of the aircraft;
a total of three propeller-rotor torque transmissions may be installed on the aircraft, for example, one in the right-hand section of the aircraft, another in the left-hand section of the aircraft, and a third at a location forward or aft of the above-mentioned right-ha
Armstrong Westerman Hattori McLeland & Naughton LLP
Eldred J. Woodrow
LandOfFree
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