Fluid reaction surfaces (i.e. – impellers) – Sustained ancillary movement of rotary working member – Responsive to fixed actuator
Patent
1998-09-17
2000-08-29
Look, Edward K.
Fluid reaction surfaces (i.e., impellers)
Sustained ancillary movement of rotary working member
Responsive to fixed actuator
416114, B63H 300
Patent
active
061098760
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a helicopter.
BACKGROUND OF THE INVENTION
The core part of a helicopter is the main rotor. With its two and more blades hinged on a rotor head and supported for pivotal movement about their longitudinal axes, to provide lift and propulsion. To produce or increase thrust for the lift, the pitch of the rotor blades is adjusted collectively, that is, synchronously. The lift of the aircraft is produced by increasing the thrust vector of the blades with the aid of a control which synchronously alters the pitch of the rotor blades.
The helicopter pilot controls the rotor blades by a swash plate comprising a rotary axially movable and tiltable part, supported by radial and axial bearings on a stationary part mounted to a gear housing, which by so called scissors controls the pitch of the blades, the blades being driven by a rotor mast. The rotary part is secured to the rotor head by another set of a scissors.
The movement of the swash plate is transmitted, via a lever mechanism, to the blade connections located at the rotor blade input correction before or behind the blade fixtures, in a manner such that the angle of incidence of the rotor blade increases or decreases with the adjustment of the swash plate.
For a flying manoeuvre, the helicopter pilot adjusts the swash plate by a single lever mechanism. In progressive rotor systems, parallel to said mechanism are disposed hydraulic servomotors which, on one hand, facilitate the control and, on the other, make possible a superimposed regulation, which counteracts the rotor blade oscillations that otherwise occur. To this end, hydraulic servomotors and active hydraulic dampers which are situated in the rotating system, individually control separate rotor blades.
One or more gas turbines drive the main rotor, via a gear and a main rotor mast, which is rotatably supported in the gear housing and on which is fixed the rotor head.
The hydraulic servomotors and active hydraulic dampers need hydraulic power of about 1% of the main rotor power. Separate pumps are used for this. These have a considerable weight and demand substantial installation space. In addition, the feed-in lines to the servomotors are often long and complex, especially when they pass from a stationary part to a rotary part.
The problem, on which the invention is based, is to supply the hydraulic motors and active dampers with the required power, to save weight, to reduce construction costs and to improve efficiency.
SUMMARY OF THE INVENTION
In the helicopter, according to the invention, the relative movement between both parts of the swash plate is used to power a pump. Even though all kinds of pumps, capable of producing the required pressure, are possible, reciprocating pumps, both in axial and in radial designs, are especially adequate. In this case, the pistons and cylinders form a working space. The pistons are actuated by a cam track on a plate in the case of axial reciprocating pumps and on a cam ring in the case of a radial reciprocating pump. Thereby the working spaces increase and decrease whereby the pumping effect is produced.
The position of the pump is distinguished by the fact that the size of the swash plate is either not increased or only very slightly. In addition, the connecting passages to the servomotors are very short both in the stationary part of the helicopter and in the rotating system. If the pump is used only for supplying consuming devices in the rotating system, the cylinders are conveniently located in the rotary part of the swash plate, thereby avoiding expensive pressurized oil connections between the rotating and stationary parts.
Since the speed of the main rotor is limited by the load capacity of the rotor blades and the velocity of the rotor blade ends, a sufficient number of cylinders and/or cams must be distributed on the periphery in one or two serial arrangements. By using numerous cylinder units a uniform flow rate is achieved and this overcomes the danger of oscillations on start up. This danger is further reduced if the cylinders
REFERENCES:
patent: 4243358 (1981-01-01), Carlock et al.
patent: 4274808 (1981-06-01), Garner et al.
patent: 4362085 (1982-12-01), Venuti, Jr.
patent: 5011373 (1991-04-01), Aubry et al.
Japanese Abstracts, Publ. No. 07040896A, dated Feb. 10, 1995, Japan Aviation Electron Ind.Ltd.
Presentation at the 39th Annual Forum of the American Helicopter Society, St. Louis, Missouri, May 1983, "On Developing and Flight Testing a Higher Harmonic Control System", pp. 3-19.
Look Edward K.
McAleenan James M
ZF Luftfahrttechnik GmbH
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