WO1992020917A1 - Rotor libre - Google Patents

Rotor libre Download PDF

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Publication number
WO1992020917A1
WO1992020917A1 PCT/GB1992/000904 GB9200904W WO9220917A1 WO 1992020917 A1 WO1992020917 A1 WO 1992020917A1 GB 9200904 W GB9200904 W GB 9200904W WO 9220917 A1 WO9220917 A1 WO 9220917A1
Authority
WO
WIPO (PCT)
Prior art keywords
rotor
further characterized
stalk
rotation
wind
Prior art date
Application number
PCT/GB1992/000904
Other languages
English (en)
Inventor
Colin Humphry Bruce Jack
Original Assignee
Colin Humphry Bruce Jack
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB919110791A external-priority patent/GB9110791D0/en
Priority claimed from GB919111437A external-priority patent/GB9111437D0/en
Priority claimed from GB919118385A external-priority patent/GB9118385D0/en
Application filed by Colin Humphry Bruce Jack filed Critical Colin Humphry Bruce Jack
Publication of WO1992020917A1 publication Critical patent/WO1992020917A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B17/00—Other machines or engines
    • F03B17/06—Other machines or engines using liquid flow with predominantly kinetic energy conversion, e.g. of swinging-flap type, "run-of-river", "ultra-low head"
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
    • F03D13/20—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/90—Mounting on supporting structures or systems
    • F05B2240/91—Mounting on supporting structures or systems on a stationary structure
    • F05B2240/917—Mounting on supporting structures or systems on a stationary structure attached to cables
    • F05B2240/9176—Wing, kites or buoyant bodies with a turbine attached without flying pattern
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/90—Mounting on supporting structures or systems
    • F05B2240/92—Mounting on supporting structures or systems on an airbourne structure
    • F05B2240/921—Mounting on supporting structures or systems on an airbourne structure kept aloft due to aerodynamic effects
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/90—Mounting on supporting structures or systems
    • F05B2240/92—Mounting on supporting structures or systems on an airbourne structure
    • F05B2240/922—Mounting on supporting structures or systems on an airbourne structure kept aloft due to buoyancy effects
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/728—Onshore wind turbines

Definitions

  • Wind generators are a clean source of energy.
  • existing designs are inherently poor in several respects. Power is generated in the form of a very large torque force acting on a large propellor (or other rotor) turning at low rpm. Massive bearings and gears are required to hold the rotor in place and convert its motion to power. Heavy structural demands are made on both the rotor blades and the support tower. Capital and maintenance costs are therefore high.
  • a wind generator which is lighter, cheaper and requires less maintenance than existing designs.
  • the essential feature of the design is that a rotating structure (which may take the form of a propellor similar to that of a conventional horizontal-axis wind turbine, or another type of rotor) extracts energy from the wind without the need to exert any torque or bending force on any central support.
  • the device may be airborne and connected to the ground only by a tethering cable.
  • the rotor is arranged (by tilting its axis) so that the drag force created on it as a result of its operation is tilted upward from the horizontal, opposing the tension in the mooring cable, and if desired also providing a net lift force which helps support the structure against gravity.
  • Electricity may be generated using small rotors attached to outer points of the main rotating structure and driven at high speed by its rotation.
  • the secondary rotors can be conventional propellors; or machines normally used as vertical-axis turbines such as Cycloturbines or Savon is Rotors or Darrieus turbines.
  • the axis of rotation of the secondaries and their attached generators can be arranged parallel to the axis of rotation of the main rotor, eliminating gyroscopic torque forces.
  • the devices can be used for weather/climate control. Whereas ground based wind generators within the boundary friction layer have little net effect on the wind, airborne generators slow the wind in which they are placed. Tilted airborne generators induce vertical air movement, sucking air (typically moving faster and at a lower temperature) downward from higher altitudes.
  • an extended aerial wind farm can be used to exert significant control over the weather.
  • the temperature of an area can be controlled by steering and/or diminishing hot or cold winds selectively; and the rainfall by steering and/or diminishing moist and dry winds.
  • Smog control can be performed by forcing clean air from higher altitude down to mix with relatively static air at ground level. Amplification effects (such as the 'butterfly effect') might permit significant climate control even with small numbers of generators.
  • devices deployed for climate control need not necessarily be equipped with secondary propellors and generators for electricity manufacture, and can therefore be cheaper.
  • SUBSTITUTE SHEET A similar design to the above, but immersed in water rather than air, can extract energy from an ocean current or tidal flow, generating electricity.
  • Water immersed devices can also perform climate control, in particular by slowing and/or diverting hot or cold ocean currents, and promoting mixing of ocean waters from different depths.
  • a line of the devices, placed for example across the mouth of an estuary, can constitute a 'virtual barrage' generating a significant head tf water on the up-flow side.
  • arrows labelled W denote wind direction unlabelled arrows indicate direction of movement.
  • 'STALK' refers to a stack of primary rotors, in others it denotes the system of tethers used to anchor a single rotor to the ground.
  • the central spherical helium balloon A provides static lift which supports the device against gravity.
  • the balloon A is connected by a plurality of tensile members W (only some of which are shown) to a surrounding rigid triangle of members C, D, E, at the corners of which are attached three rotor blades I, J, K, via joints F, G, H which hold them rigid with respect to the central triangle but permit them to be rotated about their axes so as to vary the pitch of each blade.
  • the device is attached to the mooring cable V via a rotating joint at the connecting structure U which allows the entire structure to rotate as a unit.
  • the rotating joint may be actively counter-rotated by means of a small motor to prevent the mooring cable V beoming twisted as the device spins.
  • Tensile members R, S, T connect the 1 ' nlring structure U to the central support triangle.
  • Additional tensile members O, P, Q (which may have a streamlined airfoil-like cross-section, rather than circular, so as to minimize the drag on them induced by the structure's rotation and thus minimi TO the energy so wasted) connect directly to the rotor arms I, J, K. They become taut when the device is operating, so greatly reducing the bending forces which the rotor arms must be capable of withstanding, and thus their structural weight.
  • the energy of rotation imparted to tiie structure by the wind is harvested by means of small secondary propellors L, M, N connected to high-rpm aircraft-type generators. These propellors are driven through the air at many times the incident wind speed due to the structure's rotation. Because the energy in an airflow is proportional to the cube of the velocity, and the main rotor tips may be driven at up to — 12 times the incident wind speed, relatively small secondary propellors can harvest all the energy generated.
  • the pitch of the primary blades is varied with wind speed to keep the rate of rotation constant: thus the secondary propellors may be fixed in pitch yet drive generators at constant r.p.m.
  • the device may be deployed at almost any location.
  • a particularly advantageous site is at sea over the continental shelf.
  • the tether V then connects to a buoy (not shown) and mooring line to the sea bed.
  • the device hangs vertically with most of the tether V floating on the water and the structure U a short distance above the surface.
  • the static lift of the balloon A is just sufficient to support the weight of
  • the device may also be force-started.
  • An electric generator is also a motor, so power can be fed to tiie secondary propellors to initiate rotation of die device, so providing manoeuvering control i ⁇ -Vr ⁇ -r ⁇ ing ⁇ ver ⁇ m a ff ⁇ calm.
  • the -n ⁇ -'tt-r'* and orientation of the lift force may be controlled by altering the pitch of the individual rotor blades as the device turns. In this way the mooring line is lifted .
  • Cyclic pitch control of the rotor blades can be used to alter tiie inclination of the axis of rotation, forcing it a few degrees up or down from the inclination of the mooring line, and so controlling -be altitude of the device.
  • a substantial lift force can be generated to prevent ti e drag on the central balloon forcing the structure down into the sea.
  • a balloon which is polygonal e.g. a la Buckminster Fuller geodesic with stiff cables or belts attached internally to the balloon's surface, whose intersection points may also provide convenient anchorages for tiie guy wires W
  • 'spoiler' devices to the structure;
  • the device may be built and serviced at a land-based facility, e.g. in a dockside hangar. It may be towed to its mooring when already airborne, allowed to autorotate as it does so, by a small boat, and recovered in the same way.
  • Sensing devices may include accelerometers, inclinometers, rotation sensors, wind sensors, force sensors, altitude sensors, etc. Control may be exerted solely by varying the pitch of the primary rotor blades or in other ways, e.g. with aerodynamic control surfaces; varying the length of combinations of any of the wires O, P, Q, R, S, T, W; pumpimg ballast water up and down a pipe within the tether; etc.
  • the cables O, P, Q attach to the rotor arms I, J, K at tiie point on the chord corresponding to the centre of lift, via hinges which may be recessed into the wing surface. There may be means provided to tighten and slacken, or jettison altogether, the cables O, P, Q and/or the cables R, S, T during deployment and/or recovery operations, to ensure the cables O, P, Q do not exert unwanted bending forces on the rotor arms at these times.
  • Lifting gas will leak from the balloon over time. This may be compensated by including water ballast which is progressively jettisoned; or an insulated flask of hydrogen or helium which evaporates in a controlled way to replenish tiie lifting gas; or providing a pipe or pipes within tiie mooring tether which can be used for pumping lifting gas and/or water ballast up to the structure from below.
  • the power generated is transmitted to land down the tether (ohmic heating of the tether cable as a side-effect will help prevent icing) and then via seabed cable.
  • Power will typically be generated at high frequency and relatively low voltage; boosted to higher voltage by a transformer on the seabed, or floating immersed attached to the mooring line for easier recovery; transmitted to land; then transformed or inverted to reduce the frequency to mains supply.
  • the high frequency power may be inverted to DC, transmitted efficiently to land and then across a DC land grid, and restored to AC near the point of consumption.
  • wires labelled O, P, Q, R, S, T, W are possible, including different numbers of attachment points and choices of attachment points to the central balloon, support triangle, and rotor arms. Winches or hydraulic pistons may permit the lengths and tensions of any of these wires to be varied. Additional wires may be employed, for example connecting the rotor arms one to another, or to the central balloon, to make the structure stronger and/or more rigid. Internal wires within the central balloon may pull it into a puckered shape so as to make the airflow over it more turbulent.
  • the rotor arms may be hinged so that they hang vertically when the device is static, and are deployed by centrifugal force as the device is started by forcing rotation using the secondary propellors.
  • the rotor inner ends may be connected directly to the central balloon by tensile cables without the need for a central support triangle: when the device is not operating the blades hang vertically beneath the balloon.
  • tiie guy wires may be capable of being wound in and out in synchrony with each attached to an individual electric winch at its endpoint(s). Alternatively the guy wires may initially be held to minimum length by ties which break open as the structure spins up, and all but the outer guys may be jettisoned as the structure spins down for recovery.
  • the tensile cables R, S, T may be replaced by rigid structural members forming a rigid tetrahedron whose vertices are F, G, H, U.
  • central rigid triangle C, D, £ may be inside rather than outside the central balloon.
  • the central triangle may be another structure, e.g. one having more sides and/or members extending in the structure's axial direction rather than being confined in a plane.
  • Shrouds may be mounted on structural members to minimize drag on them and hence wasted energy.
  • Gyroscopic forces on the propellors and their attached generators as their axis of rotation is forced to change
  • the propellor axles may have mount points both forward and aft of the propellors to help counter this.
  • the propellors may as shown in Figure 2a be connected to gears A which drive generator shafts in tiie opposite direction to ti e propellors so minimizing the net angular momentum and hence the gyro torque force the system exertson its mount.
  • Secondary propellors may be mormte m counter-rotating pairs. Or a plurality of small propellors may be used in place of each secondary propellor. Due to their higher rotation speed, these can be mounted each on the same axle as its generator, with no gear transmission. Half tiie small propellors in each assembly rotate clockwise, the rest anticlockwise.
  • Propellors (Fig 2b) whose axis is parallel to in incident airflow may be attached to gears A which drive generator shafts B at right angles, thus the attached generators C may be aligned with their spin axis parallel to the spin of the main structure.
  • the secondary propellors are mounted near tiie tips of tiie primary rotor blades and their direction of rotation is correctly chosen, they may interact beneficially with the airflow over the primary blades by cutting down the airspill over the ends of tiie primary blades and minimizing the tip vortices thus created.
  • Conventional propellors may be mounted on the rotor blades with their axes of rotation parallel to the structure's spin axis if deflector plates around tiie propellors deflect the surrounding airflow through them.
  • tiie central balloon is omitted, and the autogyro-like lift provided by the rota ⁇ on of the rotor keeps its weight airborne.
  • power supplied from the land drives the secondary propellors to force the structure to continue rotating so it continues to fly but in a helicopter-like manner.
  • the central rigid triangle is omitted and the rotor blades attach directly to the central balloon which is either inflated to sufficiently high pressure to itself act as a compressive structural member and or reinforced with internal compressive members.
  • the balloon may take an axially elongated form (more like an airship) extending as far as the joint U, and the wires O, P, Q may attach to the airship hull. Additional wires from the rotor arms to the aft end of the hull may help prevent them bending downward when the device is not operating and its axis is vertical. Cross-wires from points on the rotor arms to points on the circumference of the airship hull may help secure the rotor arms against sideways movement.
  • the rotor blades have biplane form, thus improving their ability to withstand bending forces at the expense of aerodynamic efficiency. This may make it possible to eliminate the tensile members O, P, Q.
  • the central balloon is not spherical but takes a more conventional airship-like shape whose axis of symmetry is the axis of rotation of the structure.
  • tiie mooring cable V does not rotate and so may be given a streamlined airfoil-like profile, said housing enclosing the various structural cables, electric cables, control signal cables, pipes, etc. .
  • the central balloon may be a rigid-hulled structure.
  • panels of corrugated fibre-reinforced plastic are strong and also help seed surface turbulence as the structure rotates.
  • a water-immersed variant of the device is shown in Figure 2e. It can have approximately neutral buoyancy and of course requires no central lifting balloon.
  • the blades A may be made, for exan ⁇ le, of fibre-reinforced wood; or hollow steel filled with a light oil fraction or ice or compressed air. Alternatively they may be made of fabric like a paraglider.
  • the structure can be equipped with secondary rotors for electricity generation as in Example 1, or be used for weather/climate control purposes only.
  • the key element of the device is a large rotor blade (the 'BEAN') which is deployed at an angle to the incident wind as shown in Figure 3, in which a twin-bladed main rotor A is seen from the side at the moment during its rotation when it lies in the vertical plane.
  • the central tether K is the axis of rotation of the whole system, comprising the rotor and all tethers attached to it.
  • the wind force on the rotor generates both a torque force tending to accelerate its spin, and a lift force directed along the axis of the rotor, as in tiie hybrid type of aircraft called an autogyro.
  • tiie primary A is allowed to rotate with a tip speed up to ⁇ 7 times greater than the windspeed.
  • the secondary propellors B should have a combined capture area about 1/200 that of the primary, so they each have a diameter about 1/20 that of the primary.
  • Variations in wind speed can be coped with by varying .the pitch and/or tiie rotation speed of the secondaries B.
  • the primary A can comprise a simple rigid structure, as distinct from a variable-pitch propellor whose geometry can be altered.
  • Altiiough tiie large primary A rotates a low r.p.m.
  • the secondaries B spin at high r.p.m.
  • Tip speed of B can be up to ⁇ 50 times wind speed, and will be limited only by tiie speed of sound in most circumstances.
  • the propellors B provide low torque force at high r.p.m., and can drive efficient electric generators with either no intermediate gearing or a single stage of gearing.
  • Propellors B are of conventional size, and can function for ⁇ 5,000 hours without maintenance.
  • the generators to which they are attached can provide high power to weight ratios, (up to several kw/kg) since high disspiative losses are acceptable and power may be generated at high frequency (e.g.250 Hz), with subsequent transformation to mains frequency on the ground.
  • the primary blade is tethered to the node C below not just at the centre D, but at several points E, F along each wing of tiie blade, thus distributing tiie strctural load evenly.
  • Some of tiie tethers L run to points E near the leading edge of each wing, and some to points F further aft, so that the orientation of the propellor is fixed by its postion with respect to tiie anchoring node C.
  • the tethers E, F may have an aerodynamically shaped cross-section so as to minimize the drag force on them as they rotate.
  • the primary blade may be thicker towards tiie central axis, where drag is less important, to prevent it buckling under longitudinal compressive force and help it resist bending.
  • the tethers L may be made of a material such as dural which has useful conducting as well as structural properties. Polyphase current can be transmitted to the ground, each tether carrying one phase. The tethers need insulation only near their endpoints.
  • the structure is capable of being 'steered', by varying the drag force on the secondaries B in synchronization with tiie rotation of tiie primary A. Thus a radial force in any desired direction may be generated.
  • the speed of rotation of the structure is controlled by varying tiie amount of drag on the secondaries B.
  • FIG. 3a A more sophisticated form of the structure is shown in Figures 3a (viewed along main axis), 3b (viewed in plane of rotation), and 3c (detail of rudder structure, viewed in elevation).
  • the secondary propellors B (4 in all) are placed away from the airflow over the rotor.
  • the structures on which they are mounted G are winglets equipped with rudders H as shown in Figure 3c, each resembling the tailplane of an aircraft.
  • the tensile wires I prevent centrifugal force on the generators from bending the winglets outward. By adjusting the rudders H as the structure rotates, a large radial force can be generated in any direction.
  • a further control mechanism is provided by ailerons K set in the trailing edge of the main rotor. These can be used to vary the angle of deflection of the airflow over each wing of the rotor. Normally they will be levelled as a rotor blade travels against the wind, and inclined as it travels with the wind. This ensures:
  • reaction force Y on the wings is consistently upward of the vector X normal to the rotor, thus helping to counter the weight of the rotor and the drag on the tethering lines C.
  • control surfaces of various types may be installed anywhere on the structure, and or by swivelling the propellor/generator assemblies to provide vectored thrust
  • the structure is threaded by a major cable K. It is attached along its span to tethering lines L meeting at a node C below it, and additional tethering lines M meeting at a node N above it
  • tethering lines L meeting at a node C below it
  • additional tethering lines M meeting at a node N above it
  • BEAN elements may be assembled into a 'STALK' composed of any number of BEANs (including one) as illustrated in Figure 5.
  • the upper end of the STALK may be supported by a tethered balloon O. (This may have a streamlined airship-like shape as shown to nunimize the wind drag on it).
  • the central cable K may be made of a material having very high strength-to-weight ratio such as Kevlar.
  • the secondary cables L, M may be made of conducting material (e.g. Dural) as in Example 4.
  • the whole structure is constrained to rotate as a unit (e.g. by varying the drag force on the sets of secondary propellors B in an appropriate way) so that the central cable does not become twisted.
  • the only rotating joints required are at tiie top of the structure P, where it attaches to the airship, and the base Q, where it attaches to the ground.
  • the rotation at these points may be forced (e.g. using small electric motors) to ensure no twisting occurs at these points.
  • the STALK can be forced to a specific, optimal, elevation angle.
  • Catenary hanging of the STALK may be m __nized, to keep it straight.
  • SUBSTITUTE SHEET (c) The STALK can be forced to a given angle with respect to the incident wind direction.
  • the STALK may be bent along its length to allow for variations in wind speed and direction with altitude.
  • the structure may also be controlled when it is stationary-.
  • the secondaries can be made to induce drag (simultaneously generating a small amount of power, if desired), or driven (e.g. by electric power supplied from the ground) to produce thrust This is relevant to the starting and stopping of the rotation of the structure, to preventing rotation during deployment and recovery, and to providing lift and guidance forces during deployment and recovery.
  • Individual rotors may be equipped with tiieir own sensors for monitoring position, orientation, incident wind, etc.
  • the structure is deployed and recovered as follows. Initially the rotors rest on tiie ground adjacent to one another (or stacked). The cables connecting them are already fastened in place, but are slack.
  • tiie nodes to be labelled 1 (the node immediately below the balloon), 2 (the node below tiie uppermost rotor), 3 (the node below the second uppermost rotor), and so on in sequence.
  • the balloon might simply be released, allowing the structure to self-deploy with each rotor pulling the next into the air as it rises.
  • two sets of winches are used, designated S and T.
  • S and T Two sets of winches are used, designated S and T.
  • Initially winch set S are connected to node 1 and are taut and set T to node 2 and are slack.
  • the set S are wound out until the balloon has lifted the first rotor into the air, set T become taut and set S slack.
  • Now set S are disconnected from node 1 and connected to node 3.
  • Set T are wound out until the second rotor is in the air and set S are taut; set T are disconnected and connected to node 4; and so forth.
  • any cable which is part of the permanent structure (either the Dural conductors or the central Kevlar tether) to be wound on a winch under tension, either during deployment or recovery.
  • the STALK may be kept operating even if individual parts fail. For example if the bearings of a secondary propellor or its attached generator fail, the pitch of the blades of the stationary propellor may still be altered to produce the drag force required. If even the pitch control mechanisms fail, other secondary propellors on the other blade tips of the affected rotor may be used to control its motion so that it does not spin out of control. _
  • the supporting balloon may be equipped with small electric motors and/or rudder and fins, to allow it to manouvre. This may be useful to hold the STALK at a desired angle, e.g. to optimize performance or prevent it becoming twisted or entangled with neighbouring STALKs in exceptional weather conditions such as flat calm or high relative turbulence.
  • a manouverable balloon may also assist during deployment and recovery, by pulling the upper end of the STALK to a desired position and holding it there.
  • the supporting balloon may be a circularly symmetric shape (e.g. a flattened disk) so that it can rotate freely. This removes the need for an upper rotating join. Rotation might be assisted by small tangential propellors, to prevent twisting.
  • (c) A self-propelled airship.
  • the STALK hangs below the airship, either with all rotors aboard, or strapped just below the ship, or already deployed as a string.
  • the airship travels to the point where the STALK is to be moored. This might be e.g. a buoy or disused oil platform at sea.
  • the STALK is moored, and power generation starts.
  • the topmost element of the STALK is a heUcopter with electrically driven blades (power is provided along the STALK). After deployment, the angle of the blades is altered and the heUcopter becomes an additional power-generating autogyro.
  • the rotor or rotors might take themselves take the form of lightweight structures (rigid or inflatable) filled with a light gas or with hot air (waste heat from the generators), so that each can support its own weight by static lift
  • the secondary propellors B can be swiveUed so as to provide directed thrust, drive power being suppUed
  • the propellors B can be used to provide lift, so that each rotor can rise from the ground under its own thrust lift may similarly be provided by seperate vertical-axis propellors mounted on any rotor, or the topmost one, e.g. at the centre of the rotor. (0 The primary propellors may be spun on a ground based turntable or turntables so that they can take off and/or land using tiieir own lift force. .
  • (j) Parachutes may be deployed from any rotor, or the topmost one, to assist in recovery, (k) Jet engines or solid-propellant rockets may lift the rotors.
  • This example describes alternative sites to which the STALK may be deployed.
  • the STALK may be recovered by the same means by which it is deployed.
  • each single set of deployment equipment and storage and servicing faciUties can supply many STALKs to different sites.
  • the STALK may be attached to a buoy or moored vessel at sea. An undersea cable to land transmits the power generated.
  • the STALK may reach this site by:
  • the STALK may be attached to an unmoored sea vessel, either drifting or proceeding under power.
  • the electricity produced might be used to generate a storable fuel, such as hydrogen electrolyzed from sea-water.
  • the vessel may foUow a course so as to maximize the wind energy accessible, e.g. by remaining under one of the major jetstreams.
  • the STALK may be attached to a point on land other than than at which it is initially deployed, either:
  • the anchoring end of the STALK might be kept on board the vehicle (which could be secured to the spot by ties), or transferred to a separate ground anchorage point
  • the STALK might be deployed to a hill or mountain top to minimize tether length and/or maximize wind speed past the rotors.
  • both the primary and secondary rotors may have an unrestricted number of blades. There may be any number of secondary blades (from zero to several) on each primary blade tip.
  • the geometry of the rotors may be alterable in other ways.
  • rotating collars at the central join may permit the pitch of the blades to be altered.
  • the length and or anchorage points of the tethering lines C and E may be capable of variation (e.g. by winches, hydrauUc pistons, etc.) so as to warp the rotor, or move one part relative to another, or vary cycUcaUy in such a way that the plane of rotation of the rotor Ues other than normal to the central tension cable.
  • the rotors may be attached to the central cable only at the midpoint (with no auxiliary supporting lines C, E to other points as shown in Figures 3) if they are sufficiently strong.
  • a biplane rotor could be of this type.
  • appropriate moving joints e.g. a universal joint
  • the joints might be motor driven so that the rotor could be forced to a chosen angle with respect to the central cable.
  • the blades of the rotor need not necessarily Ue in the same plane, e.g. they might form a shallow cone.
  • the dihedral angle may be adjustable.
  • the central joint may hinge freely so that the blades adopt an equilibrium angle determined by the ratio of centrifugal force to axial drag force.
  • the rotor blades may be deployed only once aloft, e.g. if they are tensile or inflatable structures.
  • the rotor blades may be capable of extended deployment once the rotor is in die air and rotating, e.g. by the blades extruding telescoping sections, or by allowing the central structure to extend so increasing the overall diameter of the rotor.
  • the lengths of the bracing wires L, M may be adjustable.
  • the rotor blades may be de-iced by circulating waste heat from the generators along them (e.g. in tiie form of hot air) or by electric heating elements.
  • the directions of rotation of the secondary propellors mounted on a given rotor may be chosen so as to minimize gyroscopic forces as tiie rotor turns.
  • Rotors may be mounted on a non-rotating cable by means of a bearing permitting rotation. Consecutive sections of the main cable may rotate in different directions or at different speeds if they are joined at a collar or bearing permitting rotation. In either of these cases, individual rotors may turn each at an independent speed and in either a clockwise or anticlockwise direction.
  • Rotor blades may be lofted into a Jetstream.
  • the rotor-tip energy harvesting devices may be other than propellors, e.g. enclosed turbines, turboprops, etc.
  • Pairs of counter-rotating rotors may generate energy directly from the torque force between them, without the need for rotor-tip energy harvesting devices.
  • the temperature difference between air at low level and air at high altitude may be used to generate energy, e.g. by using a working fluid which rises up the structure as a vapour, condenses at the top and flows back to the base, or the ⁇ noelectrically.
  • the rapidly turning rotors will serve as efficient heat exchangers.
  • Water may be pumped up the structure, flow out to the tips of the rotor blades and be expelled rearwards relative to the direction of turn.
  • the water may pass through turbines en route so generating energy.
  • the difference in electric potential between air at high and low altitudes may generate a current flow. This may be maximized by mati g the airflow over the rotor blades turbulent; by dissipating water vapour to increase the conductivity of tiie surrounding air; or by using trailing or fixed wires, meshes or cages attached to parts of the structure, including on the rotor blades.
  • Place of extraction may be selected by drawing power from a selected subset only of an extended network of STALKs, or by the STALKS themselves being mobile (e.g. as the ship-mounted variety described in Example 8(b)). .
  • the 'butterfly effect' can be employed to enable a small initial alteration to lead to a much larger subsequent change in the weather pattern, including at points remote from the STALK system(s).
  • 'Weather control' can of course include the dispersal of low-lying smog, cloud or fog.
  • dispersing smog from areas such as tiie Los Angeles basin by injecting clean air from higher altitudes using a BEANSTALK or cascade thereof.
  • This exan ⁇ le describes in more detail how electric power may be conveyed from the generating sites on the STALK to the ground.
  • Tn g ⁇ lnt_v * conducting members may be cooled by allowing cold air to pass along a passage within them.
  • the airflow may be created by passive means, e.g. using tiie fact that hot air rises; using the dynamic pressure of tiie wind; using the dynamic pressures created by the turning of the rotors (e.g. by having air enter and
  • SUBSTITUTE SHEET leave from slots or scoops situated on the rotor wings); and/or using the Venturi or Bernoulli effects. Air may enter and leave such a system at many points along its height
  • the transmission voltage may be raised well beyond tiie insulation limits of individual generators if a chain of generators are connected in series. Since generators are effectively isolated from the ground as weU as from one another, a high potential difference between generators, or between a the generator casing and the earth, does not matter.
  • Power may be generated at different frequency from that required (e.g. as DC to minimize the weight of tiie conductors carrying tiie current to the ground, or at high frequency to minimize the mass of the generators), being transformed to mains frequency by apparatus on tiie ground.
  • lightning strikes may be protected against either by arranging for circuit breakers, isolators etc. situated anywhere on the structure (on tiie rotors or on the cables) to effectively insert a large thickness of ⁇ nmilating material between individual rotor blade tips, between separate rotors, and or between ti e rotors and tiie ground below; or by arranging for all of tiie conductors to be cross-connected so that all cables which normally transmit power from the rotors to the ground act as a combined Ught ⁇ ing conductor of high capacity.
  • An apparatus identical or very similar to that described in each above Example may be deployed in water, as distinct from in air, to harvest energy from the flow of water in tiie form of an ocean current, a tidal flow, or a river current
  • the structure may be given an overall negative buoyancy, positive buoyancy, or neutral buoyancy.
  • the anchorage point of the tether may be to a fixed structure situated on the sea bed below; or to a fixed structure situated on land above; or to a fixed intermediate point (such as the peak of a submarine mountain); or to eitiier a mobile structure or a second rotor system which may be eitiier floating or airborne and is immersed in a medium flowing at a different speed and/or in a different direction to the current surrounding tiie rotors.
  • a STALK of rotors each having a stight positive buoyancy is tethered to a point on the seabed beneath a permanent ocean current
  • Such currents have speed — 10 times less than wind speeds: however sea-water is 1000 times denser than air, so the density of kinetic energy available per unit area is similar to that for an airborne structure.
  • Current may be transmitted from the STALK base to land via an urdersea cable.
  • the salt-water in which the system is immersed may be used as a current conductor (e.g. for one phase of an alternating current produced).
  • tiie rotors are in sea water whose temperature differs from that of its surroundings (e.g. in a warm current such as tiie Gulf Stream, or due to tiie temperature difference between the sea surface and the depths)
  • the relative thermal energy in each tonne of sea-water may be 4 to 5 orders of magnitude greater than ti e kinetic energy.
  • This Example describes in more detail how the STALK described in Example 5 may be deployed and recovered.
  • the balloon supporting the top of tiie STALK is an an unmanned airship equipped with electric motors (powered from the ground via the STALK) which are capable of propelling it in any lateral direction. If the airship has circular symmetry (e.g. disk shaped) this may be accomplished without changing orientation. (The motors may also be capable of propelling it in the vertical direction.)
  • the airship may use a Ughter than air gas such as hydrogen, helium or methane, to provide lift; or hot air; or steam; or a combination (to permit both high lift and controllability).
  • air gas such as hydrogen, helium or methane
  • power e.g. to heat hot air
  • Th ⁇ lift force from the airship may be varied by taking on board or expelling overboard ballast (e.g. water) an ⁇ or by taking on board or expelling overboard gas (e.g. hydrogen, hot air, steam) and or by condensing steam to water or vice versa and/or by its motors.
  • ballast e.g. water
  • gas e.g. hydrogen, hot air, steam
  • the airship's motors keep it in the correct relative position to the BEANs on the ground below.
  • the secondary propeUors on the airborne BEANs may be energized (using power from the ground) to maintain the BEANs in a precisely vertical line, and prevent them from twisting with respect to one another.
  • the BEAN which has most recently left the ground is moved accurately into position with respect to the one it is about to puU aloft So the whole airborne structure is precisely controlled throughout deployment.
  • the secondary propeUors are insufficient for lateral flight control (for instance in the case of twin-bladed primary rotors, whose secondaries can provide thrust in only one direction relative to the rotor) then the, primary rotors may have additional propeUors whose function is to provide thrust in other directions.
  • the BEANSTALK is recovered by a similar procedure.
  • the secondary propeUors are used to halt the rotation, and then, they and the airship's propeUors are used to return the structure to a vertical position above the landing site. lift from the airship is then steadily decreased (e.g. by venting lifting gas, or allowing hot air to cool, or by pimping ballast water up the STALK), so that the structure descends at a steady rate.
  • the shock is absorbed by undercarriage structures (e.g. skids or wheels) at the tips and/or centre of each rotor.
  • each rotor is landed in the correct position with respect to those already on the ground (e.g. adjacent to but not on top of the preceding rotor).
  • the connecting STALK cables may also be deposited on the ground in any desired pattern, e.g. a zigzag which does not cross itself or the rotors, or a loose pile or coil, in which they occupy minimum ground space.
  • the airship itself is recovered.
  • the STALK may be transported to another site than its launch one. After initial vertical deployment, the STALK may be detatched from the ground, allowing the airship to proceed under its own power (e.g. petrol engines) to the destination site, to which the base of the STALK is secured.
  • the base of the STALK may be fixed to a surface vehicle (e.g. an oceangoing tug). This vehicle may provide electric power to the STALK to drive along the airship and rotors (preventing any excessive forces in the STALK cable, or twisting, etc. from occurring) so that the vehicle and BEANSTALK proceed together to the deployment site.
  • the base of the STALK is then connected to the deployment site (e.g., transferred from an oceangoing tug to a mooring buoy).
  • the structure may take off/land with the help of streams of air provided by fans or jet tiuusters on the ground.
  • the structure may take off/land with the help of ground effects a la hovercraft.
  • the structure may take off/land with the help of magnetic levitation.
  • Possible flight modes include one in which the main rotor blades provide lift force without rotating, i.e. like a kite.
  • rotor blades may connect to the central STALK by tensile wires only (held taut by centrifugal force during operation).
  • Such blades may be equipped with control surfaces allowing them to take off and land horizontally like an aircraft (individually or together).
  • a circular runway with a rotating central structure may constitute the ground base.
  • the runway may be conventional, or take the form of a circular canal, lake, railway track, or maglev track.
  • Individual blades may be capable of separating and/or joining to the STALK in mid-air, taking off and landing separately for maintenance while the STALK continues to function.
  • a rotor may rise from the ground under its own lift either using its secondary propeUors to provide helicopter ⁇ like vertical takeoff; or accelerating the primary horzontally until it generates lift like an aircraft wing for horizontal takeoff; or by tilting a non-rotating primary so that it lifts in the wind like a kite; or by spinning the primary so that it itself generates a heUcopter type lift; or by spinning the primary tilted with respect to tiie prevailing wind so that it provides autogyro-type lift (the secondaries may provide any necessary lateral force(s) in each case.)
  • These flight modes may also be used in circumstances (such as in light winds) where the rotors must be kept aloft, but not generate power or cause high tensile forces in the STALK tether.
  • the main rotors may have an upwardly arched form so that in wind die tips are puUed apart from one another, preventing a compressive force in the rotor arising due to the tension in the secondary tethers.
  • each main rotor may be connected by wires running approximately circumferential to the rotor (from blade tip to blade tip, and or intermediate points on each blade), for additional strength and rigidity.
  • the secondary propeUors may themselves be equipped with tertiary propeUors (and so on) for power extraction; e.g. to provide power at the highest possible revs.
  • the structure may take off or land from water (e.g. the sea surface). Parachutes may assist an unpowered 'splashdown'.
  • the BEANSTALK structure may weU make use of active control systems to guide it during deployment, recovery, and power-generating operation. These systems may use sensors to detect relevant parameters (e.g. rotor position and orientation, wind speed, etc.), situated on the ground below and/or on any parti ' s) of the structure, including on each rotor blade and also on the airship. Control may be provided by a single computer (e.g. on the ground
  • SUBSTITUTE SHEET below or on the airship or micro-processors situated on each rotor (which may have faciUties for communicating with one another and/or with a main controlling computer) or any combination or multiplication of such systems.
  • Individual rotors and or the system as a whole may be intrinsically unstable, stability being provided by the active control system(s).
  • the rotating STALK tether may be clad in counter-rotating ailerons to minimize the wind force on it
  • the STALK may have an upper rotating part (including the rotors) joined at a rotating collar to a lower part which does not rotate. This lower part may be given an aerodynamicaUy shaped cross-section, to minimize wind force on it
  • some controllable ailerons may be provided so that the movements of tiie STALK tether itself may be actively controUed.
  • the rotor blades may be hinged so that during deployment they hang parallel to the STALK and swivel outward under centrifugal force when rotation is initiated.
  • tiie blades may be all-tensile and very numerous (e.g. strips of shaped plastic deploying into a Maypole-like structure). The strips may be each of slightly different length so that the secondary propeUors at their tips do not collide with one another during deployment The strips may be controUed by twisting them at either end.
  • the ends of the hinged blades (and/or intermediate points on the blades) may be connected by tensile wires so that the blades are forced into a rigid cone under centrifugal force.
  • a BEAN rotor may be deployed in the sky as an all-tensile structure which is initiaUy folded (e.g. as a slotted parachute which bells out and starts rotating under wind force).
  • the secondary propeUors may be attached to the rotor tips, or any other part of the rotors, or deployed from the rotors (e.g. on tensile tethers deployed further outward by centrifugal force).
  • the system of using secondary propeUors to extract energy from a main rotor at higher revs/lower torque than could be done directly can be appUed to an otherwise conventional ground-based rotor of any type.
  • the secondary propeUors may have the effect of diminishing the vorticity introduced into the airstream due to the rotation of the primary. This may increase the efficiency of the system and also cut down interactions between neighbouring turbines on the same STALK, and between adjacent STALKs.
  • a single airship may support more than one STALK, or be fastened to the ground by conventional tether(s) as weU as by energy-generating STALK(s), particularly to aid deployment and recovery.
  • a single STALK may be supported by more than one airship.
  • SUBSTITUTE SHEET An airship connected to the ground by conventional tether may deploy a free-hanging STALK of rotors.
  • the rotors, tending to trail behind the airship, may be flown up to an altitude above the airship itself, e.g. to intercept higher wind speeds.
  • the secondaries may be turned into the verical plane eitiier simply by turning the whole rotor into this plane (especially in the case of a two-bladed rotor) or by swivelling the mounts on which the secondaries are mounted or by swivelling the end parts of the primary rotors.
  • Single-rotor systems can include a very large rotor (up to — 1 km radius).
  • the rotor might take the form of an airship, or a structure which is unfolded or inflated or deployed by centrifugal force from the airship, which may itself spin with the rotor.
  • the speed at which the secondary propeUors turn may be controUed by varying the resistivity (inductance, resistance, capacitance, reactance etc.) of tiie circuits to which they are connected, especially if they are of fixed-pitch design.
  • Consecutive rotors of the STALK may be directly connected by wires which physically prevent them becoming twisted with respect to one another.
  • a set of rotor blades which do not aU lie in the same plane may be cross-connected into a cylindrical structure having effective three-dimensional rigidity.
  • Emergency recovery procedures may incude separating the rotors forming a BEANSTALK from one another by means of explosive bolts, and deploying parachutes from each rotor tip (or rotor centre) to slow their fall. If the airship and STALK escape from their ground anchorage, the airship envelope may be opened by remote control to cause the system to fall into the sea or onto uninhabited land.
  • Cross-wires which support the rotor blades may attach to the central STALK cable or to a rigid vertical spar forming part of the rotor.
  • Cross-wires may repeatedly bifurcate as they run from the node to their anchorage points on the rotor. Since aerodynamic forces are ⁇ 10 times greater than gravity forces on each rotor, each rotor might have supporting cross-wires to a node below but not to a node above. Of course not all cross-wires from a given rotor need
  • SUBSTITUTE SHEET terminate at the same node, and there may be a gap between the point where cross-wires running upward from one rotor meet tiie central STALK support and that at which the cross-wires running downward from the next rotor above meet the central STALK support
  • the secondary propeUors may be oriented in another direction than facing the local airflow (i.e. approximately tangential to the main rotor).
  • aerodynamic surfaces may be employed which divert tiie direction of tiie local airflow to drive ti e secondaries effectively.
  • De-icing of the rotor blades may be effected by electric heating or by circulation of coolant (e.g. heated air) warmed by the electric generators.
  • coolant e.g. heated air
  • This heated coolant may also be used to provide buoyancy, e.g. pumped to a hot-air airship supporting the BEANSTALK.
  • Attitude sensors aboard the rotors may include fibre-optic gyros.
  • Position sensors may make use of a radar system very similar to the precision landing guidance systems used at many airfields.
  • two-bladed main rotors occupy little ground area compered to rotors with 3 or more blades, and so may be landed side by side.
  • Very large 2-bladed rotors may be transported on a long narrow vessel such as an oceangoing barge.
  • the primary rotors may be twin bladed with high tip speed to airspeed ratio and the secondaries multi-bladed with low tip speed to airspeed ratio.
  • the airship may be launched to altitude while the rotors remain on the ground below.
  • the rotors then climb the airship tether cable using wheeled attachments which grip it.
  • the rotors ascend in procession with the main tether (incorprating high strength and current carrying capacity) shing between them, until the main tether becomes taut.
  • An airship at the STALK top may be supplied via a STALK pipeline with materials including liquids which are then heated to become lifting gas, e.g. water to steam, liquid methane to gaseous, etc. Control of the lift force of the airship may also involve cooling lifting gas to liquefy: steam to water, gaseous to liquid methane, etc.
  • the STALK pipeline may supply combustible fuel (liquid or gas), as weU as electricity, to power the airship and provide any auxiliary power or heating required on the rotors or the STALK itself (e.g. to prevent icing).
  • the top rotor may be connected to it with tethers connecting the outer parts of the rotor to the outer parts of the airship, so that the airship is constrained to rotate with the BEANSTALK without the uppermost part of the cable becoming twisted.
  • the circular airship may be equipped with propeUors which force it to rotate at the same speed as the STALK.
  • the secondary propeUors on the rotors may be used to twist the lowest rotor to a different angle to that it would normally make with the airship above during recovery, so it may be landed with any desired orientation (e.g. parked parallel to the rotors already on the ground) irrespective of changes in the airship's orientation.
  • the secondary propeUors on a rotor may be brought to a halt just before the rotor is landed, and turned to such a position that the tips of the secondaries avoid hitting the ground (e.g. parallel to the ground in the case of twin-bladed secondaries).
  • the secondaries may be used to force-start the initial rotation of the STALK (e.g. foUowing initial deployment). To do this, power is supplied to the generators to which the secondaries are attached, so that they act as motors and drive the secondaries, as described above.
  • a disk-shaped airship combines the properties of rotational symmetry (so it may turn with the STALK), minimal wind drag, and the ability to act as a lifting-body aircraft when tilted with respect to the wind. In wind, the tension of the STALK wiU tend automatically to tilt it in an appropriate way to accomplish this.
  • a STALK may support turbine(s) of the Darrieus type in any of the foUowing ways.
  • the turbine blades may be all-tensile structures deployed by centrifugal force:
  • the STALK may form a single turning Darrieus blade as in Figure 7(a).
  • the STALK may form a zigzag of single Darrieus blades as in Figure 7(b).
  • the STALK may be constitute the central column of one or more Darrieus turbines each having two or more blades as in Figure 7(c).
  • the STALK may bifurcate (or trifurcate etc.) into one or more Darrieus turbines each having two or more blades and no central column as in Figure 7(d).
  • SUBSTITUTE SHEET hanging from an airship An end weight or aerodynamic device such as a propeUor or drogue parachute may help maintain tension in tiie tether.
  • Force on the Darrieus blades may be varied, by means of control surfaces or by twisting the blades or by manipulating the secondary propeUors, e.g. to control' the orientation of the turbines and/or to control the direction and magnitude of tiie wind force on them (e.g. to provide a lift force).
  • the secondary propeUors may be situated at a slightly different point on each blade making up a Darrieus turbine as in Figure 7(e), so that they do not collide during deployment
  • Figure 8a shows a 'front' view during initial deployment; Figure 8b a 'side' view during rotation initiation (one rotor blade only visible); Figures 8c-f side views during operation; and Figure 8g a reinforcing boom.
  • a spherical balloon A supports via tensile cables B two or more primary rotor blades C (which may be tensile or semi-rigid or rigid structures) which at their ends support assembUes which comprise secondary rotors D attached to electric motor/generators E (there may be just one secondary rotor per assembly, or an array containing a large number of small secondary propeUors each with its own attached motor/generator) and also aerodynamic surfaces F used for control purposes as described below.
  • primary rotor blades C which may be tensile or semi-rigid or rigid structures
  • assembUes which comprise secondary rotors D attached to electric motor/generators E (there may be just one secondary rotor per assembly, or an array containing a large number of small secondary propeUors each with its own attached motor/generator) and also aerodynamic surfaces F used for control purposes as described below.
  • the balloon A rises into the air with the cables B and their attached blades C banging approximately vertical and supporting the assembUes D E/F.
  • the balloon A may be capable of powered lateral motion (including during the ascent) either by using electric power to drive the secondary propeUors at the rotor ends, or by separate motors G mounted closer to the central baUoon A (e.g. upon or beneath it).
  • Each assembly F may actually consist of a multipUcity of aerodynamic surfaces mounted in different planes, and incorporating movable surfaces (e.g. like the tailplane assembly of a conventional aircraft) or the whole assembly being twistable with respect to the rotor wing.
  • the assembUes F are manipulated so as to control the orbit of each primary rotor blade C and also the angle of attack of its outer end with respect to to the incident airflow (and so to some extent the angle of attack and/or degree of warping of t e entire rotor blade).
  • the motion of each assembly may be likened to a familiar toy in which a model aircraft attached to a fixed tether continuously orbits a central point, but with the motion during each orbit controllable to a substantial extent.
  • the tethers to the structure may take a variety of forms.
  • Figure 8c depicts the simplest: one tether to the centre of rotation.
  • An alternative form (Figure 8d) has twin tethers to each rotor blade tip (none to the central balloon).
  • Figure 8e shows a variant of this form;
  • Figure 8f a variant in which bifurcating tethers attach ultimately to many points along each main rotor.
  • Figures 8d - 8f could all be modified to include an additional tether to the central baUoon.
  • the main bearing H permitting rotation of the whole system may be sited on the ground below (or upon a sea buoy) as in Figure 8c or at the cable main bifurcation point as in Figures 8d-8f or at any intermediate point (or points if redundancy is desired, so the structure can continue functioning if a main, bearing fails).
  • Rotation is rapidly halted, the rotor blades being steered so that they do not collide with each other or the tether cables and coining to rest dangling vertically below the baUoon.
  • the arresting might be accomplished by braking or reversing the pitch or reversing the direction of rotation of the secondary propeUors; or (in emergency) by drogue parachutes deployed from the main rotor blade tips.
  • the balloon might then be winched in; or the secondary rotors or auxiliary motors E might be used to fly the baUoon back to tiie launch field, depositing the main tether cable on the ground or into the sea in so doing.
  • the baUoon need not be capable of carrying its payload to the altitude represented by the fuU tether length.
  • the net lift of the system may be varied (e.g. to assist during launch or recovery) e.g. by releasing lift gas or ballast water from the ' " loon, and/or by pumping lift gas or ballast water up the tether to the baUoon.
  • Tetiier cables may be aerodynamicaUy shaped to minimize wind resistance due to incident wind and or main rotor rotation.
  • tether cables wiU tend to trail behind the rotors to which they are attached: if the secondary propeUors are mounted on ti e leading side of each primary rotor blade, they will not tangle with the tethers.
  • the buoy may be designed so that it can without harm be dragged beneath the water or lifted out of the water by the tension of the main tether during operation.
  • the central baUoon may be reinforced by internal wires; in particular connecting the various anchoring points of the main rotors, so that tiieir centrifugal force does not add to the stress in the baUoon fabric.
  • the fabric may be reinforced at intervals along tiie wingspan by structural members called booms (running forward to aft, i.e. circumferential with respect to the centre of rotation) which can hold the fabric in the desired cross- sectional profile shape.
  • booms running forward to aft, i.e. circumferential with respect to the centre of rotation
  • the angle of inclination at each boom can also be controUed, eitiier
  • the angle of attack might be adjustable, e.g. by varying the angle of inclination of the tailplane or the relative lengths of the fore and aft cables, permitting accurate 'trimming * for different wind conditions and or during each primary rotor orbit (g) It is possible to deploy a stack of the structures described in this Example as a 'STALK', tethered to one another, rotating synchronously, and using a common main bearing and ground anchorage point (h) A variant of tiie design could be deployed underwater, e.g. in an ocean current The central baUoon could be replaced by a small buoy. If the object was to slow or divert the current rather than generate power, the secondary rotors would be used only to initiate deployment: dissipative structures such as rotortip

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Abstract

Un rotor libre est une structure totalement rotative, extrayant de l'énergie cinétique d'un flux dans lequel elle se trouve de telle façon qu'elle ne subit aucun couple net. Il est relié via un joint contrarotatif (Fig. 1:4) à un câble d'amarrage (Fig. 1:V). La structure est inclinée de manière que la force de traînée s'exerçant sur le rotor soit dirigée vers le haut par rapport à l'horizontale, produisant une force ascendante qui empêche que la structure soit tirée vers le bas par la tension du câble, et qui peut également supporter son poids gravitationnel. L'énergie électrique peut être générée au moyen d'hélices secondaires (Fig. 1: L, M, N) montées sur la structure en des points situés à l'extérieur du centre et contraintes à traverser le milieu environnant à une grande vitesse du fait de la rotation de la structure. L'application principale envisagée est celle d'une éolienne.
PCT/GB1992/000904 1991-05-18 1992-05-18 Rotor libre WO1992020917A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
GB9110791.2 1991-05-18
GB919110791A GB9110791D0 (en) 1991-05-18 1991-05-18 Autogyro wind generator
GB919111437A GB9111437D0 (en) 1990-06-25 1991-05-28 Autogyro wind generator version 2
GB9111437.1 1991-05-28
GB919118385A GB9118385D0 (en) 1991-05-18 1991-08-28 Autogyro wind generator version 3
GB9118385.5 1991-08-28

Publications (1)

Publication Number Publication Date
WO1992020917A1 true WO1992020917A1 (fr) 1992-11-26

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PCT/GB1992/000904 WO1992020917A1 (fr) 1991-05-18 1992-05-18 Rotor libre

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AU (1) AU1749992A (fr)
WO (1) WO1992020917A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19502948A1 (de) * 1995-01-31 1995-07-06 Manfred Dr Baumgaertner Anlage zur Erzeugung elektrischer Energie aus Windkraft
WO2010125063A2 (fr) * 2009-04-28 2010-11-04 Ingenieurbüro Persang GmbH & Co. KG Dispositif et procédé pour convertir l'énergie cinétique contenue dans un écoulement d'eau en énergie électrique
EP1731759A3 (fr) * 2005-06-09 2012-03-14 Yehuda Roseman Dispositif pour la production d'énergie du jetstream
ITTO20130480A1 (it) * 2013-06-12 2013-09-11 Kite Gen Res Srl Sistema e procedimento di messa in volo di profili alari di potenza, in particolare per generatore eolico.
CN104033318A (zh) * 2014-03-12 2014-09-10 雍占锋 缆绳传递扭矩的柔性联轴器及应用这种联轴器的发动机

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FR977987A (fr) * 1942-12-04 1951-04-09 Anciens Etablissements Billard Moteur hydraulique
US3987987A (en) * 1975-01-28 1976-10-26 Payne Peter R Self-erecting windmill
US4450364A (en) * 1982-03-24 1984-05-22 Benoit William R Lighter than air wind energy conversion system utilizing a rotating envelope
US4491739A (en) * 1982-09-27 1985-01-01 Watson William K Airship-floated wind turbine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR977987A (fr) * 1942-12-04 1951-04-09 Anciens Etablissements Billard Moteur hydraulique
US3987987A (en) * 1975-01-28 1976-10-26 Payne Peter R Self-erecting windmill
US4450364A (en) * 1982-03-24 1984-05-22 Benoit William R Lighter than air wind energy conversion system utilizing a rotating envelope
US4491739A (en) * 1982-09-27 1985-01-01 Watson William K Airship-floated wind turbine

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19502948A1 (de) * 1995-01-31 1995-07-06 Manfred Dr Baumgaertner Anlage zur Erzeugung elektrischer Energie aus Windkraft
EP1731759A3 (fr) * 2005-06-09 2012-03-14 Yehuda Roseman Dispositif pour la production d'énergie du jetstream
WO2010125063A2 (fr) * 2009-04-28 2010-11-04 Ingenieurbüro Persang GmbH & Co. KG Dispositif et procédé pour convertir l'énergie cinétique contenue dans un écoulement d'eau en énergie électrique
WO2010125063A3 (fr) * 2009-04-28 2011-05-05 Ingenieurbüro Persang GmbH & Co. KG Dispositif et procédé pour convertir l'énergie cinétique contenue dans un écoulement d'eau en énergie électrique
WO2014199406A1 (fr) * 2013-06-12 2014-12-18 Kite Gen Research S.R.L. Système et procédé de démarrage du vol de profils d'aile de puissance, en particulier pour aérogénérateur
ITTO20130480A1 (it) * 2013-06-12 2013-09-11 Kite Gen Res Srl Sistema e procedimento di messa in volo di profili alari di potenza, in particolare per generatore eolico.
CN105308311A (zh) * 2013-06-12 2016-02-03 凯特金科研有限公司 用于启动动力翼翼面的飞行的、特别用于风力发电机的系统和方法
KR20160017088A (ko) * 2013-06-12 2016-02-15 카이트 젠 리서치 에스. 알. 엘. 특히 풍력 발전기용 파워 윙 에어포일의 비행을 시작하기 위한 시스템 및 프로세스
JP2016522349A (ja) * 2013-06-12 2016-07-28 カイト ゲン リサーチ エス．アール．エル．Ｋｉｔｅ Ｇｅｎ Ｒｅｓｅａｒｃｈ Ｓ．Ｒ．Ｌ 特に風力発電機用の、パワーウイング翼の飛行開始のためのシステムおよびプロセス
AU2014279653B2 (en) * 2013-06-12 2018-04-19 Kite Gen Research S.R.L. System and process for starting the flight of power wing airfoils, in particular for wind generator
RU2655432C2 (ru) * 2013-06-12 2018-05-28 Кайт Джен Ресерч С.Р.Л. Система и способ для отправки в полет аэродинамических профилей энергетического крыла, в частности для ветрового электрогенератора
CN105308311B (zh) * 2013-06-12 2018-05-29 凯特金科研有限公司 用于启动动力翼翼面的飞行的、特别用于风力发电机的系统和方法
KR102152845B1 (ko) 2013-06-12 2020-09-07 카이트 젠 리서치 에스. 알. 엘. 특히 풍력 발전기용 파워 윙 에어포일의 비행을 시작하기 위한 시스템 및 프로세스
CN104033318A (zh) * 2014-03-12 2014-09-10 雍占锋 缆绳传递扭矩的柔性联轴器及应用这种联轴器的发动机
CN104033318B (zh) * 2014-03-12 2017-09-19 雍占锋 缆绳传递扭矩的柔性联轴器及应用这种联轴器的发动机

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