Aeronautics and astronautics – Aircraft – heavier-than-air – Helicopter or auto-rotating wing sustained – i.e. – gyroplanes
Reexamination Certificate
1999-01-22
2001-02-06
Swiatek, Robert P. (Department: 3643)
Aeronautics and astronautics
Aircraft, heavier-than-air
Helicopter or auto-rotating wing sustained, i.e., gyroplanes
C244S017110
Reexamination Certificate
active
06182923
ABSTRACT:
The invention relates to a helicopter in accordance with the preamble of claim
1
herein.
The direction of flight of a conventional helicopter may be changed by alteration of the angle of the rotor blades. Thus more particularly in the case of coaxial helicopters with rotors moving in opposite directions collective and cyclical adjustment of the blade angle is employed in order to maneuver the helicopter in the vertical and, respectively, in other directions. Whereas in the case of collective blade adjustment, which brings about a vertical flight maneuver, the angle of attack of the rotor blades is globally changed, cyclical blade adjustment means that the angle of attack of an individual blade is changed in a particular position of rotation. Cyclical blade adjustment, which causes forward flight or, respectively, a change in the direction of flight to the side, is conventionally brought about by means of a swash plate arranged functionally adjacent to a rotor shaft.
It is a disadvantage in the case of such known helicopters that the cyclical blade control by means of such swash plates leads to a more elaborate design so that the costs of production and weight are correspondingly increased. Moreover, the swash plate system is subject to a high wear rate, something which makes necessary the replacement of expensive parts at short intervals of time. Cyclical blade adjustment furthermore requires an additional amount of power, something which reduces the efficiency of the drive system.
Accordingly one object of the present invention is to create a helicopter in accordance with the preamble of claim
1
, which is able to be controlled by means of a simpler, more economic and more readily serviced control system and furthermore has a higher efficiency.
This object is to be achieved by the features of claim
1
. Advantageous developments of the invention are described in the further claims.
In the case of the helicopter of the invention the rotor system is able to be moved in translation in the longitudinal direction of the helicopter fuselage together with the drive system and is able to be pivoted about a pivot axis running along the fuselage. Owing to the longitudinal displacement of the rotor and drive system in relation to the fuselage the center of gravity of the helicopter is so changed that the helicopter is inclined about its transverse axis forward and, respectively, backward so that forward flight may be accelerated and, respectively, retarded. The pivoting about the pivot axis running along the fuselage on the other hand causes an inclination of the helicopter to the left or to the right so that it is possible for corresponding curves to be flown.
The helicopter in accordance with the invention offers the advantage that cyclical blade control, that is to say the swash plate and its control elements, may be completely dispensed with so that the overall structure is substantially simplified. This means that there are lower costs of production, less wear, substantially longer intervals between servicing and therefore lower serving costs. Furthermore mechanical effort for cyclical blade angle addition is no longer necessary and accordingly the efficiency of the overall system is improved. A further advantage is that owing to the possibility of inclining the rotor system about the longitudinal axis of helicopter improved take-off and landings on hills become possible.
The control of the center of gravity of the helicopter of the invention further leads to a significant saving in weight and to operation of the rotor with less vibrations. Moreover following engine failure gliding with the rotor freewheeling (autorotation) is substantially simpler, the use of a suitable inclination of the rotor blades shortly before landing meaning that a relatively gentle touch-down is possible even without engine drive. The helicopter furthermore responds extremely rapidly to corresponding changes in the center of gravity so that extremely precise and simple control or steering of the helicopter is possible. Unlike known helicopters response to control commands is improved with an increase in load, that is to say a higher mass of the fuselage instead of being reduced.
In accordance with an advantageous embodiment of the invention a semi-cardanic suspension is provided for longitudinal transverse and pivoting of the rotor system, such suspension having at least one central support axle held on the fuselage. The central support axle in this case simultaneously defines both the longitudinal axis, along which the rotor system and possibly the drive system is able to be longitudinally moved, and also the pivot axis, about which the rotor and possibly the drive as system well may be laterally tipped.
In accordance with an advantageous embodiment of the invention the adjustment of the blade angle is performed by means of longitudinal displacement of a sliding sleeve, which is held on the rotor shaft in a manner allowing sliding but not rotary movement and is functionally connected with the rotor blades.
Such a sliding sleeve is preferably arranged to be longitudinally slid by means of a linkage, which is fixed on the sliding sleeve in the direction of sliding while being held in relation to same while allowing relative rotary movement and is able to be slid using a lever mechanism in the longitudinal direction of the rotor shaft.
REFERENCES:
patent: 3045950 (1962-07-01), Jennings, Jr.
patent: 3765622 (1973-10-01), Haines
patent: 2 155 817 (1973-03-01), None
patent: WO 84/00339 (1984-02-01), None
patent: WO 97/44240 (1997-11-01), None
Nixon & Vanderhye PC
Swiatek Robert P.
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