NASA Wind Energy Airborne Harvesting System Study

U.s. Patent Application Number: 11/830,769

Tethered Wind Turbine

Douglas J. Amick

Filed July 30, 2007



Short Description:

The tethered wind turbine uses an aerodynamic, flow concentrating shape and lighter-than-air construction utilizing a lifting gas and an electrically conductive tether fixed to the ground to reap energy from the wind at low or high altitude. Stabilizers and control surfaces can also be added for additional stability and control.

U.S. Patent 4,073,516

Wind Driven Power Plant

Alberto Kling

February 14, 1978


Short Description:

A tethered wind-driven floating power plant which includes a support body carrying at least one rotor assembly, a current generator coupled to the rotor and alignment assembly for aligning the rotor to face into the wind, a ground anchor and at least one captivating stay connecting the floating power plant to the anchor. The support body is hollow and gas-filled to carry its own weight as well as the weight of the rotor assembly, current generator and alignment assembly.

U.S. Patent 4,084,102

Wind Driven, High Altitude Power Apparatus

Charles Max Fry and Henry W. Hise

April 11, 1978


Short description:

Wind driven rotors are affixed along the length of a flexible power shaft, and the shaft is suspended at a great height above the earth by means of a swivel. The lowermost end of the shaft is connected to rotate a ground supported energy conversion device. The winds aloft impart rotational motion into the wind rotors, whereupon the rotational energy of the shaft is converted into electrical power or other form of power by the conversion device.

U.S. Patent 4,285,481

Multiple Wind Turbine Tethered Airfoil Wind Energy Conversion System

Lloyd I. Biscomb

August 25, 1981

Short Description:

A plurality of wind turbines are supported aloft on the same tethered airfoil which is provided with devices for orienting the wind turbines into the wind.

U.S. Patent 4,309,006

Tethered Airfoil Wind Energy Conversion System

Lloyd I. Biscomb

January 5, 1982


Short Description:

A generally toric lighter-than-air gas bag-type airfoil is tethered to the ground at a plurality of angularly widely distributed points about the periphery of the gas bag. A wind turbine is mounted at the entrance to the axially central vent. The tether lines are entrained about individually operable power winches, preferably controlled by a microprocessor which takes in wind direction and tether line tension data and operates the winches and inflation gas inlet and outlet valves to orient the wind turbine into the wind for maximum power output.

U.S. Patent 4,350,896; 4,350,897

Lighter Than Air Wind Energy Conversion System Utilizing an Internal Radial Disk Diffuser

Lighter Than Air Wind Energy Conversion System

Lighter Than Air Wind Energy Conversion System Utilizing An External Radial Disk Diffuser

Lighter Than Air Wind Energy Conversion System Utilizing A Rearwardly Mounted Internal Radial Disk Diffuser

William R. Benoit

September, 21 1982


Short Description:

A lighter-than-air (LTA) wind energy conversion system (WECS) wherein the gas-filled LTA envelope carries a main rotor and electrical generator to take advantage of high winds available at high altitudes. The LTA envelope is tethered to a ground based mooring system designed to provide self-orientation for the LTA envelope. In a preferred embodiment, heavy mechanical transmissions are eliminated by providing a radial diffuser within the LTA envelope coupled through a drive shaft to a wind-driven external rotor. Rotation of the rotor-diffuser drives an induction turbine positioned within the gas inlet to the diffuser, the lifting gas for the envelope also serving as the working fluid for the turbine. The output of the induction turbine is coupled to an electrical generator whose output is, in turn, transmitted to the ground via the tethering system.

U.S. Patent 4,450,364

Lighter Than Air Wind Energy Conversion System Utilizing A Rotating Envelope

William R. Benoit

May 22, 1984

Short Description:

See 4,350,896; 4,350,897; 4,350,898; and 4,350,899. The LTA envelope is adapted rotate with the main rotor and is tethered to a ground based mooring system designed to provide self-orientation for the LTA envelope. In a preferred embodiment, a hollow bladed main rotor is provided at the midpoint of the rotating envelope. The rotor drives an induction turbine positioned within a substantially linear duct which is, in turn, preferably located along the longitudinal axis of the rotating LTA envelope.

U.S. Patent 4,486,669

Wind Generator Kite System

Paul F. Pugh

December 4, 1984

Short Description:

The wind generator is suspended in the air like a kite by wind currents and is attached to the earth by a high strength cable to which are attached electric cables and a natural gas pipe. The numerous small wind generators are mounted in a box-like kite enclosure, which are raised to the desired elevation by rotary blade power with the assistance of a gas balloon.

U.S. Patent 4,491,739

Airship-Floated Wind Turbine

William K. Watson

January 1, 1985

Short Description:

This is a wind turbine that, supported by a tethered airship, may be designed for the economical recovery of power at heights of 2,000 ft or more above the ground.

U.S. patent 4,572,962

Apparatus For Extracting Energy From Winds At High Altitudes

David H. Shepard/Cognitronics Corp.

February 25, 1986 

Short Description:

A wind-operated power-generating module for operation at high altitudes such as 1000 meters comprising a frame structure mounting a pair of vertically-separated parallel shafts around which pass endless belts supporting a series of parallel, elongate wing-like elements for movement around a closed path including the parallel shafts. Wind flow drives these elements around the closed path, to enable electrical power to be generated, and also provides lift to hold the module up at the appropriate altitude. A number of such modules are tethered in fixed positions in the sky, and are controllable as is appropriate to accommodate changing wind conditions.

U.s. patent 4,659,940

Power Generation From High Altitude Winds

David H. Shepard/Cognitronics Corp.

April 21, 1987

Short Description:

A kitecraft secured to a ground tether supports a cylindrical drum rotatable about a horizontal shaft. The drum comprises a plurality of wheels interconnected by airfoils positioned about the cylindrical surface of the drum. Wind action on the airfoils rotates the drum about the horizontal shaft and turns generators to provide electrical power.

U.S. patent 4,832,571

Flexible Tethered Wind Turbine

Frank L. Carrol

May 23, 1989

 Short Description:

A flexible shaft supported by guy wires is provided at its upper end with a flexible rotor and an airfoil assembly. Rotation of the airfoils in response to wind creates centrifugal force and tension, which causes the rotor to become rigid during use. The light flexible shaft easily follows the rotating sails, which permits the entire turbine to automatically track the wind as it changes direction. As the rotor spins, its rotational energy is transferred to the shaft, which rotates along its entire flexible length.

u.s. patent 6,091,161 

Method of Controlling Operating Depth Of An Electricity-Generating Device Having A Tethered Water Current-Driven Turbine

James G. P. Dehlsen, James B. Dehlsen, and Geoffrey F. Deane

July 18, 2000

Short Description:

This is a tethered airfoil with wind turbines attached on both sides. The turbine is designed for use in water, but the concept could easily be applied for use in the wind.

U.S. patent 6,254,034

Tethered Aircraft System For Gathering Energy From Wind

Howard G. Carpenter

July 3, 2001

 Short Description:

The tethered aircraft of the system is blown by wind to travel downwind at a controlled rate for maximal mechanical energy gathering from wind whose velocity fluctuates and gusts. A cycle of travel is completed when the aircraft is has travelled upwind to the site of the beginning of downwind travel, where downwind travel is recommenced. The downwind travelling aircraft pullingly unwinds its tether from an anchored windlass drum to spin the rotor of an interconnected electrical machine to convert mechanical energy to electricity.

U.S. patent 7,129,596

Hovering Wind Turbine

Aleandro Soares Macedo

October 31, 2006

Short Description:

A hovering wind turbine whose blades lie on the surface of an imaginary horizontal cylinder and have their pitch angle changing as a function of the rotational angle, allowing them to gather wind energy mainly in the upwind and downwind sectors of the cylindrical path and to use a fraction of the gathered energy to create lift by deflecting air downwards, mainly in the upper and lower sectors of the cylindrical path. The remainder of the gathered wind energy is used to drive a pair of on board electrical generators, and anchoring tethers carry electrical current to a land of offshore site. The turbine is tied to a blimp that is purposely located in its wind shape and keeps it airborne during periods of light or no wind.

u.s. patent 7,183,663

Precisely Controlled Flying Electric Generators

Bryan William Roberts and David Hammond Shepard

February 27, 2007

Short Description:

One or more tethered platforms, each having three or more, mill rotors, are operated at altitudes in relatively high winds to generate electricity. These windmill kites use one or more electro-mechanical tethers on each platform. Their position, attitude and orientation are monitored by one or more GPS receivers and/or gyros and controlled through differential thrusts and torque-reactions produced by the mill rotors. The kites can be electrically powered from a ground supply during relatively calms periods, or landed if desired. During windy periods the kites may be used to generate electricity by tilting the rotors at an angle, or incidence to the oncoming wind.

U.s. patent 7,335,000 

Systems And Methods For Tethered Wind Turbines

Frederick D. Ferguson/Magenn Power, Inc.

February 26, 2008

Short Description:

This patent describes systems and methods for tethered wind turbines. The system may comprise an airborne body extending horizontally along an axis between a first and a second point, wherein the body is at least partially filled with a gas. The system may further comprise, for example, two or more vanes coupled to the body such that the vanes, when acted upon by a wind force perpendicular to the axis are operable to cause the body to rotate about the axis to generate a Magnus effect lifting force. The system may also have one or more tethers coupled to anchor the body to a third point.

u.s. patent 5,149,020

Tethered Rotary Kite

Craig V. Rundle and Gary L. Hooten

September 22, 1992

Short Description:

This is a tethered, wind-powered flying device, generally known as a roto-kite, which allows for flight even in slight wind conditions and also functions well in strong wind conditions.

u.s. patent 6,781,254 

Windmill Kite

Bryan Williams Roberts

August 24, 2004

Short Description:

See 7,183,663. A kite having a flying platform including a plurality of mill rotors, at least one tethering line maintaining the platform at a substantially fixed geographical location, at least one dynamo on the platform drive connected to the mill rotors, and a conductor connecting the dynamo to an electrical transmission and supply system at ground level.

u.s. patent 3,987,987

Self-Erecting Windmill

Peter R. Payne and Charles McCutchen

October 26, 1976

Short Description:

A device which lifts itself into the air and either itself carries a windmill for extractions of power from the wind, or traverses a oscillatory path back and forth across the wind such that the action of the tethering lines for the device can be used to generate useful power (such as electricity).

u.s. patent 7,317,261

Power Generating Apparatus

Andrew Martin Rolt

January 8, 2008

Short Description:

This is a power generating apparatus including a cable which rotatably mounts a plurality of power units. The power units include wind power turbines for producing power from the wind as the power units fly in the sky whilst connected to the cable.

u.s. patent 4,207,026

Tethered Lighter Than Air Turbine

Oliver J. Kushto

June 10, 1980

Short Description:

This patent describes a wind turbine comprising a lighter than air body affixed to a drive line. Vanes or fins are attached about the body and turn the body in response to air currents acting thereon. This turns the drive line to supply rotational energy to a load.

u.s. patent 4,470,563


Gijsbert J. Engelsman

September 11, 1984

Short Description:

One or more lighter-than-air bodies carry wind energy catching rotor devices, like windmills, turbines, or similar, and catch energy from the wind, which is transmitted mechanically to the earth by at least one endless cable-rope transmission.

u.s. patent 4,166,596

Airship Power Turbine

William J. Mouton and David F. Thompson

September 4, 1979

Short Description:

Power is mechanically transmitted from a tethered airship carrying wind turbines to electrical generators on the ground at the anchor point of the tether, by the use of endless power-transmission cables bridging between drive sheaves at the turbine wheels and driven sheaves at the generators.

u.s. patent 6,616,402

Serpentine Wind Turbine

Douglas Spriggs Selsam

Short Description:

Multiple horizontal axis type rotors are coaxially attached along the upper section of an elongate torque transmitting tower/driveshaft. The tower/driveshaft projects upward from a cantilevered bearing means, and is bent downwind until the rotors become sufficiently aligned with the wind to rotate the entire tower/driveshaft. Power is drawn from the shaft at the base. Aerodynamic lifting bodies or tails, buoyant lifting bodies, buoyant rotor blades, and methods of influencing the tilt of the rotors, can help elevate the structure.

u.s. patent 7,188,808

Aerialwind Power Generation System And Method

Gaylord G. Olson

March 13, 2007

Short Description:

This is an aerial power generation system that includes a guide line supported by a support body. Wind driven elements are configured and shaped to provide maximum force from both lift and drag during the downwind phase of operation and minimum force during the upwind phase. The guide lines add stability to the system and provide better control over the angular orientation and direction of motion. Power transfer is through one or more tow lines connected from the driven elements to power generation devices on the ground.

u.s. patent Application number: 10/656,004

Wind Energy Production Using Kites And Ground Mounted Power Generators

Gordon Bruce Kingsley

Filed September 3, 2003

Short Description:

This patent describes a system of traction kites that generate power by generating lift, which causes a cable to be unreeled from a ground-based drum and generate mechanical or electrical energy.  The kites can travel as far as the length of the cable allows. Once the final length of cable has been extended, the kites are retrieved by minimizing the angle of attack of the kites and reversing the shaft rotation of the drum to reel them back in.

u.s. patent 4,076,190

Apparatus For Extracting Energy From Winds At Significant Height Above The Surface

Lambros Lois

February 28, 1978

Short Description:

This invention employs a series of sails which may be comprised of a hollow buoyant body filled with lighter than air gas. The buoyant sail has a concave surface facing the incoming wind and is designed to lift with it the necessary tether line leading from the body to the ground level structure which might include an electric generator. The sails are employed in series with the sails alternately being played out under the influence of the wind and then drawn back while presenting a smaller effective surface to the wind.

u.s. patent 4,124,182

Wind Driven Energy System

Arnold Loeb

November 7, 1978

Short Description:

This patent describes a train of tethered kites for capturing wind energy, in which each train contains a series of kites. The trains are secured by a power line to an earthbound drum or windlass selectively rotatable in both clockwise and counter-clockwise directions to either reel in the power lines, or to enable the power lines to be pulled upwardly and outwardly by the action of the winds.

u.s. patent 6,072,245

Wind-Driven Driving Apparatus Employing Kites

Wubbo Johannes Ockels

June 6, 2000

Short Description:

This is a driving apparatus for driving a drive shaft, which includes a number of kites and at least one pulling cable, a means for varying the position of the kites. The kites are arranged to follow an ascending path and a descending path.

u.s. patent 6,523,781

Axial-Mode Linear Wind-Turbine

Gary Dean Ragner

February 25, 2003

Short Description:

The system comprises multiple airfoil kites in tandem attached to a pivotal control housing by control lines and support. The control lines can change length with respect to the length of the support lines and to control the airfoil kites’ angle-of-attack, pitch angle, direction of flight, and flight speed. Control lines and support lines are also wound on a power shaft and pulley system. The airfoil kites are reeled out under axial tension due to their lift, causing the power shaft and pulley system to turn a generator, which produces electricity. After the reel-out power stroke, the kites’ angle of attack is adjusted to minimize the cable tension so that the kites can be reeled back in.

u.s. patent 3,924,827

Apparatus For Extracting Energy From Winds At Significant Height Above The Surface

Lambros Lois

December 9, 1975

Short Description:

A buoyant wing is tethered to a line an appreciable distance above the surface where the winds are at higher speed than at ground level, the other end of the line is attached, for example, to an electrical generator, and provision is made for adjusting the position of the wing so that when a series of wings are utilized together with an electrical generator, one wing may be retracted while at least one other wing, which is positioned to catch the wind, is drawn away from the generator.

u.s. patent 4,251,040

Wind Driven Apparatus For Power Generation

Miles L. Loyd

February 17, 1981

Short Description:

This patent describes a wind driven apparatus for the production of power at a ground location. The system includes an aerodynamic lift generating vehicle capable of maintaining a stable airborne orientation, a tether linking the vehicle to a ground location, mechanical power generating equipment carried by the vehicle and responsive to relative motion between the air and the vehicle, apparatus for converting the generated power to reciprocating motion and structure for transmitting the reciprocating motion along the tether to the ground.

u.s. patent 6,914,345

Power Generation

John R. Webster/Rolls-Royce plc

Short Description:

A power generator comprising: a lifting body for suspension in a moving fluid; a control station; and at least two tethers for tethering the lifting body to the control station. The control station is arranged to transform oscillating tension in the tethers produced by an oscillating movement of the lifting body into mechanical motion.

u.s. patent 6,555,931

Renewable Energy Systems Using Long-Stroke Open-Channel Reciprocating Engines

John V. Mizzi

Short Description:

This patent includes a renewable energy system for extracting energy from the wind. The energy system is a configuration of long-stroke open-channel reciprocating engines employing airfoils tethered to a power drum to generate electricity.

u.s. patent 7,210,896

Electrical Power Generation Assembly

David S. Knott/Rolls-Royce plc

May 1, 2007

Short Description:

This is an electrical power generation assembly comprising a main body having a low density to provide lift and wind driven means on its surface to generate electrical power. The main body has a part-circular, or a part-elliptical cross-section frontal region.

u.s. patent 4,894,554

Cable Suspended Windmill

Moses G. Farmer\NASA Langley

January 16, 1990

Short Description:                  

This wind mill invention consists of an airframe having an upwind end and a downwind end, a first rotor rotatably connected to the airframe, and a generator supported by the airframe and driven by the rotor. The airframe is supported vertically in an elevated disposition by poles which extend vertically upwardly from the ground and support cables which extend between the vertical poles. Suspension cables suspend the airframe from the support cable.

u.s. patent 5,909,859

Multi-Rotor Kite Glider

Stephen J. Janicki

June 8, 1999

Short Description:

A kite employing a controllable transmission between two specialized types of rotor assemblies. The torque rotor assembly is designed to rotate when placed in a stream of wind, collecting power from the wind in the form of lift and torque.

u.s. patent 5,484,257

Wind Energy Device

Norbert L. Osborn

January 16, 1996

Short Description:

This device generates rotating shaft power from wind energy. A partition exists along the length of the leading edge of an airfoil. A turbine is placed within the airfoil and adapted to be driven by fluid pressure entering the leading edge and exiting the top surface of the airfoil.

u.s. patent 1,717,552


Alpin I. Dunn

June 18, 1929

Short Description:

The invention consists of a LTA airship that has a longitudinally extending air tube open at both ends. The tube contains an air motor adapted to be driven by the wind rushing through the tube during normal operation of the ship.

u.s. patent 6,382,904

Windmill Powerplant

Igor Sergeevich Orlov, Emmanuil Avraamovich Sobol, and Mikhail Andreevich Egorov

May 7, 2002


Short Description:

This patent describes a particular wind turbine design, not necessarily airborne. But, to achieve greater power output the turbine can be placed at high altitudes using lighter than air gases in an aerostat configuration, as the above the illustrations above imply.

u.s. patents 2,368,630

Electrically Powered Glider

Stanley Bizjak

February 6, 1945

Short Description:

This invention consists of a glider that is partially supported by buoyant gas. The glider has a propeller that can be manually disconnected from its motor in order to act as a turbine and transmit energy to a generator, which generates electricity to recharge the battery.

u.s. patent 6,925,949

Elevated Sailing Apparatus

Malcolm Phillips

August 9, 2005

Short Description:

An elevated sailing apparatus that includes one or more wings, tethered to a conveyance, and suspended from beneath a streamlined, lighter-than-air blimp.

u.s. patent 7,287,481

Launch And Retrieval Arrangement For An Aerodynamic Profile Element And An Aerodynamic Profile Element

Stephan Wrage and Stephan Brabeck/SkySails GmbH & Co. KG

October 30, 2007

Short Description:

This invention consists of an inflatable traction kite that can be used to drive a watercraft.

u.s. patent 7,504,741

Wind Energy Plant With A Steerable Kite

Stephan Wrage and Stephan Brabeck/SkySails GmbH & Co. KG

March 17, 2009

Short Description:

This patent describes a tethered traction kite that generates lift from the wind causing the tether to unravel from a ground-based drum, which is connected to an electricity-producing generator.

u.s. patent 4,335,093

Process Of Converting Wind Energy To Elemental Hydrogen and Apparatus Therefor

Robert E. Salomon/ Temple University

June 15, 1982

Short Description:

This is a modified sailing vessel that uses a balloon as a means of propulsion. While underway, an immersed screw propeller converts the ship’s motion into rotational motion, which provides power to an electromagnetic generator which, in turn, produces electricity. The electric current is then used to electrolytically decompose water into hydrogen and oxygen.

u.s. patent 5,150,859

Wingtip Turbine

Thomas F. Ransick/ Sundstrand Corporation

September 29, 1992

Short Description:

An apparatus for generating power from a trailing vortex induced at the wingtip of an aircraft. A turbine is mounted on the wingtip and is disposed in the trailing vortex.

u.s. patent 7,582,981

Airborne Wind Turbine Electricity Generating Sytem

Moshe Meller

September 1, 2009

Short Description: 

An airborne system for producing electricity from wind energy includes a shaft, at least two turbines rotatably mounted to the shaft and arranged to rotate independent of one another and in opposite directions when subjected to the same wind, and generators which convert rotation of the turbines into electricity.

u.s. patent application number: 09/946,497

Method of Utilization A Flow Energy And Installation For It

Alexander Alexandrovich Bolonkin

Filed September 6, 2001

Short Description:

The invention consists of a large blade-rope type wind rotor suspended by a wing at high altitude to extract huge amounts of energy from the wind. A rope transmits power to a ground-based electrical generator.

u.s. patent application number: 12/518,577

System For Performing The Automatic Control Of The Flight Of Kites

Mario Milanese, Andrea Milanese, and Carlo Novara

Filed November 30, 2007

Short Description:

A system is described for performing the automatic control of the flight of at least one kite controlled and driven by cables comprising at least one first actuating motor adapted to exert unwinding-rewinding action. This patent was filed by people involved with KiteGen.

u.s. patent application number: 12/297,406

Aeolian System Comprising Power Wing Profiles and Process For Producing Electric Energy

Massimo Ippolito and France Taddei

April 24, 2004

Short Description: 

This patent describes a system that consists of a wing profile, or kite, that is connected by two cables to a ground-based winch. The cables control the power generation and attitude of the wing profile. The wing profile generates power from the wind and transmits this power to the ground via the cables.

u.s. patent 7,709,973

Airborne Stabilized Wind Turbines System

Moshe Meller

May 4, 2010

Short Description:

See 7,582,981.  A lifting section includes combination of kites and lighter than air balloons, generating a lifting force that causes the system to be airborne at a desired altitude.

u.s. patent 7,214,029

Laminar Air Turbine

Donald L. Richter

May 8, 2007

Short Description:

The windmill assembly is a low drag, streamlined body of revolution that captures the kinetic energy content of the accelerated laminar air surrounding the body. The assembly includes a power-generating, wind-driven turbine that is compact, lightweight and capable of producing a substantially greater output than a conventional windmill with a comparable size rotor.

u.s. patent 6,327,994

Scavenger Energy Converter System Its New Applications And Its Control Systems

Gaudencio A. Labrador

December 11, 2001

Short Description:

This patent describes several different wide face fluid energy conversion systems based on the assumption that a larger surface results in more power conversion.

u.s. patent application number: 12/154,685

Faired Tether For Wind Power Generation Systems

Saul Griffith, Peter Lynn, Don Montague, and Corwin Hardham/ Makani Power, Inc.

Filed May 23, 2008

Short Description:

This patent application describes a tether for a wind power system.  The tether has a cross-section that is designed to have less aerodynamic drag than a tether with a circular-shaped cross-section.

u.s. patent application number: 12/302,435

Atmospheric Resources Explorer

Tiago Da Costa Duarte Pardal and Marco Aurelio Baptista De Almeida Freire

Filed May 31, 2007

Short Description:

The invention consists of tethered kites that generate power by unwinding the tether from a ground based drum under tension caused by lift. Power is generated in a work phase and the kites are reeled back in a recovery phase. The tension forces on the tether can be controlled by using a control unit that alters the flight of the kites.

u.s. patent 4,892,272

Kite-like Flying Device With Dual Handles And Four Point Control

Joseph R. Hadzicki

Filed October 14, 1988

Short Description:

A preferred embodiment of the present invention includes a kite having a sail with a left and right wing, each being connected to a supporting frame, with the frame having a leading edge support member associated with a left wing strut member and with a right wing strut member.

u.s. patent 5,533,694

Method For Locating The Resultant Of Wind Effects On Tethered Aircraft

Howard G. Carpenter

Filed March 8, 1994

Short Description:

A method for the determination of the location of the line-of-action of the resultant of the wind forces on a tethered aircraft is disclosed. The location is referenced to a line-segment that is referenced in turn to the aircraft structure.

u.s. patent 4,313,059

Sea Current Energy System

Gerald T. Howard

Filed October 20, 1980

Short Description:

A system for extracting useful energy from sea currents. A pair of drag inducing devices is disposed in the sea current, and connected by cables to a windlass at a location upstream of the drag devices. Each drag device has a selectably variable drag resistance in the sea current, and the drag.

u.s. patent 4,364,709

Wind Power Converter

August Tornquist

Filed December 30, 1981

Short Description:

A high torque windmill is provided for use in converting wind power to usable energy, having a vertical axis about which a plurality of flexible vanes are journaled for rotation and spaced radially therefrom. The vanes are circumferentially spaced and mounted on a rigid circular, multi-sided.

u.s. patent 4,327,296

Wave-Powered Motor

Paul F.R. Weyers

Filed January 8, 1981

Short Description:

A dome-shaped atoll structure (12) having a central aperture at its apex is secured to a station-keeping structure (11, or 40, or 52) positioned on the ocean bottom. The atoll structure (12) is moveable through a range of vertical positions relative to the ocean bottom. Sea waves impinging on the atoll structure (12) are refracted as they crest and break, thereby producing spiralling pulses of water that converge toward the central aperture. The central aperture provides entry into a vertical standpipe (14) for the pulses of water, which impart angular momentum to water already present in the standpipe (14). A turbine (31) attached to a shaft (28) in the standpipe (14) converts the rotational energy of the water in the standpipe (14) to rotational energy of the shaft (28), which is coupled to an electrical generator (27). The electric power output of the generator (27) is measured for various vertical positions through which the atoll member (12) is moved, so that a position of optimum power output can be determined for any given combination of sea state and/or tidal conditions.

u.s. patent 6,825,574

Spring Motor Powered Electricity Generation System Actuated By Reciprocating Natural Forces

Jon Mooring

Filed September 13, 2002

Short Description:

An electricity generation system that has the ability to generate clean electrical power by mechanically capturing the tremendous power of large trees as they sway in the wind. The system utilizes a modular unit that is mounted on a frame assembly covered by a housing. A plurality of spring motors are mounted in a spring motor housing that is journaled on an elongated spring-motor secondary winding axle. The inner end of each spring motor metal band is secured to the spring-motor secondary winding axle. The spring motor housing is releasably connected to a stationary retention plate to prevent rotation of the spring motor housing until the spring motors are wound a sufficient amount. A cable tether member has one end attached a tree trunk adjacent its upper area and the other end of the tether line is secured to the front end of a ratcheting arm. When the wind force bends the tree from it static upright position, the ratcheting arm is pulled downwardly causing a winding drive spur gear to rotate causing the spring motors to be wound incrementally each time the wind blows the tree from it static upright position. An electricity generator is mounted on the frame assembly and there is rotation transmission structure connected to the power generation drive shaft of the electricity generator. When the spring motor assembly has been sufficiently wound, a timing gear assembly releases the motor spring housing assembly allowing it to rotate freely to dissipate its stored energy and drive the electricity generator. This cycle is repeated throughout the day to generate electricity when the wind is blowing. A modified electricity generation system utilizes the wave motion of a natural body of water by tethering the ratchet arm to a floating buoy.

u.s. patent 4,684,817

Valvular Sail Power Plant

John M. Goldwater

March 11, 1985

Short Description:

A windmill generally intended to rotate in a horizontal plane about a vertical axis, includes essentially radial vanes; each which is effectively a one way valve respective to air flow; each which can enhance (or supplement) the beneficial actions of the others; and each of which vanes, in operation, effectively simulates a sailing vessel navigating a circular course in wind of constant direction. Each of said vanes includes a framework which supports a grid, which grid is the supporting means for a plurality of pivotally connected vertically aligned and overlapping light weight flexible sails, which sails are automatically rotated about said pivotal connection by the force of the wind into positions promoting the revolution of the windmill. Included with said sails are various devices as spars, springs and cords which promote and enhance their efficient automatic operation. The windmill is inherently self protecting in high winds and self regulating in speed of rotation. The windmill is shown in several embodiments and means of mounting, including which can utilize already existing structures for height and support and which float upon a body of water. Also shown are several means utilizing this invention to efficiently and inexpensively drive electrical generators, or alternators now used in automobiles, at high RPM without need of a separate step-up transmission. Discussed also is the interfacing of the electrical power generated with the existing electrical utility power lines. The windmill is shown in sizes which range from very large, for electrical generation on a commercial scale, to small sizes which can be mounted upon the roof of a household for providing electrical power directly and solely thereto. Also discussed is the use of this invention (or appropriateness) in less technologically developed, remote, or areas otherwise deficient in energy resources. Also discloses is the use of this invention to better propell sailing vessels.

u.s. patent 4,302,684

Free Wing Turbine

Laird B. Gogins

July 5, 1979

Short Description:

Apparatus to convert wind energy into mechanical and electrical energy including a variable pitch air-foil supported by tension guy wires on a wheeled structure constrained to move upon a continuous track. The structure includes electrical generators powered by the rotation of the structure's wheels to convert movement of the structure into electrical energy. The air-foil is supported upright on the wheeled structure, which is designed to resist upward, downward and sideways forces, to capture wind energy at a higher elevation above the ground where winds blow stronger.

u.s. patent 3,887,817

Power Generating Device

Gerald E. Steelman

Filed December 20, 1973


Short Description:

A power generating device comprises a continuous elongated flexible loop member having opposite loop ends and adapted to be suspended in a current of flowing fluid. The loop member is trained around a rotatable member which in turn is drivingly connected to an electrical generating power means. A plurality of flexible and collapsible containers or sails are mounted in spaced relationship and in end to end relationship along the loop member. When immersed in a current of moving fluid, the containers will be expanded and filled by the fluid when their open ends are facing upstream in relation to the current and they will be collapsed and emptied of fluid when their open ends are facing downstream in relation to the current. Thus the containers will drive the loop member and consequently the rotatable member continuously whenever the loop member and containers are immersed in a flowing fluid material.

u.s. patent 2,501,442

Rotatable Airfoil Kite

Jesse C. Donaldson

Filed April 6, 1948

Short Description:

This invention relates to aero-dynamics and more especially to an air-foil structure mounted for rotation about a longitudinal axis as a result of air flow across or at an angle to such axis.

u.s. patent 3,026,073

Rotary Winged Kite

Stanley E. Albertson Jr.

Filed July 6, 1959

Short Description:

This invention relates to kites and has particular reference to a kite having a pair of rotary wings, or air foils, which can be controlled from the ground by novel means, which enable the operator to produce a variety of interesting, entertaining, and educational results.

u.s. patent 7,093,803

Apparatus and Method For Aerodynamic Wing

David A. Culp

Filed December 16, 2003

Short Description:

Aerodynamic wing to propel a broad range of transport means, principally sail craft. The wing provides a single layer kite structure capable of flying without surface discontinuity, bridles, or rigid or semi-rigid structure. All stresses within the wing are converted into pure tension and transferred through the wing surface outward to attachment lines. The wing shape defines a large diameter self-supporting rolled over leading edge of an airfoil and the wing profile approaching the trailing edge exhibits increasing convexity. The wing is useful to propel, or supplement propulsion to, transportation means.

u.s. patent 4,129,272

Aerofoil Structure

Andrew W. Jones and Raymond Merry

Filed August 19, 1977

Short Description:

An aerofoil structure which is inflatable by ram air when in use, includes a flexible multi-cell air fillable envelope having a readily removable flexible spar at its leading edge whose ends provide anchorages for a pair of operator control lines. In use the spar flexs to accommodate variations in air speed over the envelope.

u.s. patent 4,874,146

Steerable Kite

Edmund Heid

Filed September 19, 1988


Short Description:

A steerable kite is disclosed that has lateral members, a cross-strut, a covering and a kite controlling apparatus. The lateral members are secured to each other at adjacent ends, and the cross-strut's opposing ends are each attached to a lateral member. The kite controlling apparatus is fastened at the connecting points of the lateral members and the cross-strut and lateral members. This arrangement of elements provides a kite with a single-chamber system that is operationally stable at various wind intensities.

u.s. patent 5,183,224

Self Regulating Pinwheel Kite Tail

Rudy W. Harburg

May 14, 1990

Short Description:

A swivel on a string is attached to the windward face of a pinwheel turbine. The other end of the string is attached to the aft portion of a kite thus creating a kite tail. Wind against its veins and leeward parts stabilize the pinwheel's orientation and cause it to spin. The pinwheel is light but tends to produce drag proportional to the velocity of the wind, thereby, stabilizing the kite in both low winds and high winds. A multiplicity of pinwheels can be attached in series on one kite tail, and one or more such kite tails can be attached to a kite to provide directional stability. This self-regulating tail can be used to help keep a kite airborne in an extremely wide range of wind speeds.

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