GB2045870A - Ram jet powered rotors - Google Patents

Abstract

A powered rotor comprises a plurality of arms 13, 14, 15, 16 on at least some of which ram jet motors 22, 23, are mounted. An alternator 29 is connected to the rotor by shaft 26, and gears 25, 24. The ram jet motors include compressed air nozzles opening into the combustion chamber for starting. The rotor can alternatively be used for powering a helicopter or a surface effect vehicle. <IMAGE>

Description

SPECIFICATION Ram jet rotor motor This invention relates to improvements in and appli cations for powered rotors.

Powered rotors have applications where it is desired to convert motor energy into transmittable electric power, or into motive power e.g. creating lift or working as an air or water screw.

Powered rotors are generally well known wherein the rotor (air screw, ships propellor, helicopter blades or dynamo rotor for example) is driven directly by a motor or through appropriate gearing.

The motor may be of any known type with a rotatingshaft output - internal combustion, electric, or a turbine for example.

An object of the invention is to provide a powered rotor capabie of achieving high outputs in terms of shaft horse power or torque. High values of s.h.p. are desirable for instance in generating mains electrical supplies or generating lift for helicopters or surface effect vehicles.

Usually, torque is applied to a generator for example by a wind, water or combustion engine powered rotor, such as a wind mill, water wheel, or by a take off shaft from an internal combustion engine for relatively low output systems, and gas-, water - or steam- turbines for relatively high output systems.

An object of the invention is to provide a powered rotor which can provide a power output of the magnitude required for industrially useful electrical generating plant.

In accordance with this invention, a powered rotor comprises a rotable axis having a plurality of arms in a balanced radial array, the or some of the arms each carring a ram jet reaction motor for imparting rotary momentum to the rotor.

Such a rotor may be connected, through reduction gearing if so required, to an electrical generator.

Alternative possible uses, are on the rotor blades of a helicoptor, or the fans of a ground effect vehicle (hovercraft) for providing the necessary air cushion.

Ram jets are well known, particularly in the aeronautic art, and provided for efficient fuel burn ing by use of a forced flow of air to oxidise the fuel.

The air inlet uses aerodynamic flow principles to concentrate a concentrated airflow at an annular air inlet to a combustion chamber by means of a flared intake duct, and an aerodynamically profiled central core. The motor however requires to be moving relative to the air mass, in order to achieve the ramming effect required to force compressed air through the annular inlet. Starting such a motor therefore presents a problem since the motor must already be moving at high speed relative to the surrounding air mass, for example if used as a sustainerfora guided missile, the missile may be accelerated to the required speed by discardable boosters.

Preferably, the motors are provided with nozzles for compressed air adjacent the air inlet for inducing the motor to start, and feeding the combustion chamber with air of sufficient density to sustain efficient combustion until a sufficient air speed is reached for the ramming effect to take over, and compressed air supplied through the annular inlet.

In a preferred embodiment of the invention, which is described with reference to the accompanying drawings-wherein:- Figure 1;is an elevation of an electrical generating installation including a powered rotor according to the invention; and Figure2 is a plan view of the installation shown in Figure 1 and Figure 3 is a diagrammatic axial cross-section of a ram jet motor for use in the invention.

As shown in the drawings, a plinth 10 comes a rotor 11 freely rotatable on the plinth 10 and supported by a bearing race (not shown). The rotor 11 comprises a hub pillar 12, and four generally horizontally radially extending arms 13,14,15 and 16. Each arm comprises a cage structure of four struts, which may be cross-braced by bracing struts (not shown), and also has an associated tie strut 17 extending from the top of the pillar 12 to the outer end of respective arm, and the outer ends of the arms are joined by further peripheral struts 18,19,20 and 21.

Mounted on the outer ends of two of the arms, 14 and 16 are two ram-jet motors 22 and 23, one on the end of each arm respectively. Each motor 22, 23 is mounted on the end of the respective arm so as to be rotatable in a generally vertical plane, and is arranged with its jet outlet nozzle directed slantingly outwardly, so that the thrust exerted by the motor creates a centripetal force to counteract the centrifugal force arising from rapid rotation of the whole rotor structure 11, thereby reducing the risk of one of the motors flying off. The risk of serious damage by one of the motors if it should fly off its mounting is further reduced by directing the outlet nozzles at an angle upwardly, so that any loosened engine will tend to be driven downwardly by the thrust of the jet.

Torque is transmitted from the rotor by a gear 24 on the base of the piller which meshes with a gear 25 on the end of a shaft 26, supported in a bearing 27 and passing through a wall 28 enclosing the rotor and leading to an alternator 29 which is used to generate a.c. electricity.

It will be noticed that only two of the arms carry ram jet motors. However, all four arms could be so provided, and alternative arm configurations could be provided e.g. three arms disposed at 1200 intervals each carrying a motor; so long as the weight and power distributions of the rotor is balanced.

Each ram jet motor (Figure 3) is approximately 3 metres long, with an air intake duct 30 opening over 1 metre in diameter. The duct 30 tapers to an annular inlet 31 which is centrally defined by an aerodynamically profiled cone 32. Air entering the intake 31 when the motor is moving forwards with a high air speed is compressed at the annular inlet 31, which is followed immediately by a pressure drop behind the cone 32, wherein turbulance is created. Aviation spirit is introduced by injectors 33 on the rear face of the cone 32, into the turbulent slip stream of the cone, the turbulence aiding the mixing of air and fuel. Ignition points 34 for the air-fuel mixture are provided in an annular array, by electrical spark or glow plugs, in the combustion chamber 35 down stream of the turbulent mixing zone.

For starting the rotor, it is necessary to first accelerate the motors to a peripherai speed suffi cientforthe ram jets to operate. To do this, an annular array of compressed air nozzles 36 is disposed adjacent and around the inlet 31, and there are used to support combustion and induce the necessary inlet pressure until the thrust of the jet has produced sufficient velocity. When this speed is reached, the compressed air supply can be switched off, and the motor sustained by the ramming effect of the shaping of the intake 30. The ram jet motors move at approximately 750 miles per hour when rotating at 500 revolutions per minute on rotors 15 meters in diameter.

The rotor described is for use in generating electricity and provides a relativey compact installation compared with the boilers, fuel stores, smoke stacks and cooling towers needed for the production of steam for steam turbine driven generators. Such an installation can therefore be provided in localities for example where additional generating capacity is required but the extra load does not justify the construction of a full scale nuclear or conventional generating plant.

Rotors of the kind described can also be used in other applications, for example, the fans providing the air cushions of surface effect vehicles (hovercraft) may be powered by ram jet motors mounted on arms connected to the fan rotors, provision being made by means of refractory linings and venting for coping with the effects of the hot exhausts of the motors. In addition, helicopter rotors may be powered in the manner suggested, with the ram jet motors mounted on the rim of a wheel, the spokes of which are the lift generating blades, or mounted on arms connected to the same axle as the lift blades. In this proposal, the motors may be tiltable for effecting jet assisted lift and the rotor may be turnable on a central body incorporating the cockpit which is stabilised by motors acting to rotate it in the opposite sense to the rotor.

Claims (8)

1. A powered rotor comprising a rotatable axis having a plurality of arms in a balanced radial array, the or some of the arms carrying a ram jet reaction motor for imparting rotary momentum to the rotor.

2. A rotor according to claim 1, wherein the ram jet motors are mounted so that their exhausts act centripetallyto tend to prevent the motors from flying off the rotor due to centrifugal force.

3. A rotor according to claim 1 or 2 wherein the ram jet motors are mouted so that they tend to drive downwardly.

4. A rotor according to claim 1 or 2 wherein the ram jet motors are tiltable.

5. A rotor according to any preceding claim connected by a mechanical transmission to electrical generating apparatus.

6. A rotor according to any preceding claim forming part of a lift producing fan for a surface effect vehicle.

7. A rotor according to any preceding claim incorporating lift producing blades of a helicopter rotor.

8. A powered rotor substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.