![LandYacht](https://upload.wikimedia.org/wikipedia/commons/8/82/LandYacht.jpg)
Wind-powered vehicles derive their power from
sail
A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may ...
s,
kite
A kite is a tethered heavier than air flight, heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create Lift (force), lift and Drag (physics), drag forces. A kite consists of wings, tethers and anchors. ...
s or
rotor
Rotor may refer to:
Science and technology
Engineering
*Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator
* Helicopter rotor, the rotary wing(s) of a rotorcraft ...
s and ride on wheels—which may be linked to a wind-powered rotor—or runners. Whether powered by sail, kite or rotor, these vehicles share a common trait: As the vehicle increases in speed, the advancing airfoil encounters an increasing apparent wind at an
angle of attack
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...
that is increasingly smaller. At the same time, such vehicles are subject to relatively low forward resistance, compared with traditional sailing craft. As a result, such vehicles are often capable of speeds exceeding that of the wind.
Rotor-powered examples have demonstrated ground speeds that exceed that of the wind, both directly ''into the wind'' and directly ''downwind'' by transferring power through a drive train between the rotor and the wheels. The wind-powered speed record is by a vehicle with a sail on it, ''
Greenbird
''Greenbird'' is a wind-powered vehicle that broke the land speed record for sail-powered vehicles at the dry Ivanpah Lake on March 26, 2009. It was built by the British engineer Richard Jenkins. ''Greenbird'' reached a peak speed of 126.1  ...
'', with a recorded top speed of .
Other wind-powered conveyances include sailing vessels that travel on water, and
balloon
A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...
s and
sailplane
A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplan ...
s that travel in the air, all of which are beyond the scope of this article.
Sail-powered
Sail-powered vehicles travel over land or ice at apparent wind speeds that are higher than the true wind speed, close-hauled on most points of sail. Both land yachts and ice boats have low forward resistance to speed and high lateral resistance to sideways motion.
Theory
![Ice boat apparent wind on different points of sail](https://upload.wikimedia.org/wikipedia/commons/a/a5/Ice_boat_apparent_wind_on_different_points_of_sail.jpg)
Aerodynamic forces on sails depend on wind speed and direction and the speed and direction of the craft ( ''V
B'' ). The direction that the craft is traveling with respect to the ''true wind'' (the wind direction and speed over the surface – ''V
T'' ) is called the ''
point of sail
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface.
The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind. ...
''. The speed of the craft at a given point of sail contributes to the ''
apparent wind
Apparent wind is the wind experienced by a moving object.
Definition of apparent wind
The ''apparent wind'' is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to the observer.
The ''velocity o ...
'' ( ''V
A'' )—the wind speed and direction as measured on the moving craft. The apparent wind on the sail creates a total aerodynamic force, which may be resolved into ''
drag''—the force component in the direction of the apparent wind—and ''
lift
Lift or LIFT may refer to:
Physical devices
* Elevator, or lift, a device used for raising and lowering people or goods
** Paternoster lift, a type of lift using a continuous chain of cars which do not stop
** Patient lift, or Hoyer lift, mobile ...
''—the force component
normal Normal(s) or The Normal(s) may refer to:
Film and television
* ''Normal'' (2003 film), starring Jessica Lange and Tom Wilkinson
* ''Normal'' (2007 film), starring Carrie-Anne Moss, Kevin Zegers, Callum Keith Rennie, and Andrew Airlie
* ''Norma ...
(90°) to the apparent wind. Depending on the alignment of the sail with the apparent wind, lift or drag may be the predominant propulsive component. Total aerodynamic force also resolves into a forward, propulsive, driving force—resisted by the medium through or over which the craft is passing (e.g. through water, air, or over ice, sand)—and a lateral force, resisted by the wheels or ice runners of the vehicle.
[
]
Because wind-powered vehicles typically sail at apparent wind angles aligned with the leading edge of the sail, the sail acts as an
airfoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
and lift is the predominant component of propulsion.
Low forward resistance to motion, high speeds over the surface, and high lateral resistance help create high apparent wind speeds—with closer alignment of the apparent wind to the course traveled for most points of sail—and allow wind-powered vehicles to achieve higher speeds than conventional sailing craft.
[
]
Land yacht
Land sailing
Land sailing, also known as sand yachting, land yachting or dirtboating, is the act of moving across land in a wheeled vehicle powered by wind through the use of a sail. The term comes from analogy with (water) sailing. Historically, land saili ...
has evolved from a novelty, since the 1950s, primarily into a
sport
Sport pertains to any form of Competition, competitive physical activity or game that aims to use, maintain, or improve physical ability and Skill, skills while providing enjoyment to participants and, in some cases, entertainment to specta ...
. The vehicles used in sailing are known as ''land'' or ''sand yachts''. They typically have three (sometimes four) wheels and function much like a
sailboat
A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture.
Types
Although sailboat terminology ...
, except that they are operated from a sitting or lying position and steered by
pedal
A pedal (from the Latin '' pes'' ''pedis'', "foot") is a lever designed to be operated by foot and may refer to:
Computers and other equipment
* Footmouse, a foot-operated computer mouse
* In medical transcription, a pedal is used to control p ...
s or hand
lever
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or ''fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is div ...
s. Land sailing is best suited for windy flat areas; races often take place on
beach
A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shel ...
es,
airfield
An aerodrome (Commonwealth English) or airdrome (American English) is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither, and regardless of whether it is for publ ...
s, and
dry lake bed
A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...
s in
desert
A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...
regions.
''
Greenbird
''Greenbird'' is a wind-powered vehicle that broke the land speed record for sail-powered vehicles at the dry Ivanpah Lake on March 26, 2009. It was built by the British engineer Richard Jenkins. ''Greenbird'' reached a peak speed of 126.1  ...
'', a sail-powered vehicle sponsored by
Ecotricity
Ecotricity is a British energy company based in Stroud, Gloucestershire, England, specialising in selling green energy to consumers that it primarily generates from its 87.2 megawatt wind power portfoliothe company prefers the term windmill rat ...
, broke the land speed world record for a wind-powered vehicle in 2009 with a recorded top speed of , beating the previous record of at , set by Schumacher from the United States, riding ''Iron Duck'' in March 1999.
Ice boat
![DN ice boat--Ice Nine--Lake Sunapee NH](https://upload.wikimedia.org/wikipedia/commons/3/30/DN_ice_boat--Ice_Nine--Lake_Sunapee_NH.jpg)
Iceboats designs are generally supported by three skate blades called "runners" supporting a triangular or cross-shaped frame with the steering runner in front. Runners are made of iron or steel and sharpened to a fine edge, most often cut to an angled edge of 90 degrees, which holds onto the ice, preventing slippage sideways from the lateral force of the wind developed by the sails. Once the lateral force has been effectively countered by the runner edge, the remaining force of "sail-lift" vacuums the boat forward with significant power. That power increases as the speed of the boat increases, allowing the boat to go much faster than the wind. Limitations to iceboat speed are windage, friction, the camber of the sail shape, strength of construction, and quality of the ice surface. Iceboats can sail as close as 7 degrees off the apparent wind.
Ice boats can achieve speeds as high as ten times the
wind speed
In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer.
Wind speed ...
in good conditions.
International DN
The International DN is a class of iceboat. The name stands for Detroit News, where the first iceboat of this type was designed and built in the winter of 1936–1937. Archie Arrol was a master craftsman working in the Detroit News hobby shop, ...
iceboats often achieve speeds of while racing, and speeds as high as have been recorded.
Kite-powered
Kite
A kite is a tethered heavier than air flight, heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create Lift (force), lift and Drag (physics), drag forces. A kite consists of wings, tethers and anchors. ...
-powered vehicles include buggies that one can ride in and boards that one can stand on as it slides over snow and ice or rolls on wheels over land.
Theory
A kite is a tethered
air foil that creates both lift and drag, in this case anchored to a vehicle with a tether, which guides the face of the kite to achieve the best angle of attack. The
lift
Lift or LIFT may refer to:
Physical devices
* Elevator, or lift, a device used for raising and lowering people or goods
** Paternoster lift, a type of lift using a continuous chain of cars which do not stop
** Patient lift, or Hoyer lift, mobile ...
that sustains the kite in flight is generated when air flows around the kite's surface, producing low pressure above and high pressure below the wings. The interaction with the wind also generates horizontal
drag along the direction of the wind. The resultant force vector from the lift and drag force components is opposed by the tension of one or more of the
lines
Line most often refers to:
* Line (geometry), object with zero thickness and curvature that stretches to infinity
* Telephone line, a single-user circuit on a telephone communication system
Line, lines, The Line, or LINE may also refer to:
Arts ...
or
tether
A tether is a cord, fixture, or flexible attachment that characteristically anchors something movable to something fixed; it also maybe used to connect two movable objects, such as an item being towed by its tow.
Applications for tethers includ ...
s to which the kite is attached, thereby powering the vehicle.
Kite buggy
A ''
kite buggy
A kite buggy is a light, purpose-built vehicle powered by a traction kite (power kite). It is single-seated and has one steerable front wheel and two fixed rear wheels. The driver sits in the seat located in the middle of the vehicle and accelera ...
'' is a light, purpose-built
vehicle
A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wa ...
powered by a
power kite
A power kite or traction kite is a large kite designed to provide significant pull to the user.
Types
The two most common forms are the foil, and the leading edge inflatable. There are also other less common types of power kite including rig ...
. It is single-seated and has one steerable front
wheel
A wheel is a circular component that is intended to rotate on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction wi ...
and two fixed rear wheels. The driver sits in the seat located in the middle of the vehicle and accelerates and slows down by applying steering manoeuvres in coordination with flying manoeuvres of the kite. Kite buggies can reach .
Kite board
Kite boards of different description are used on dry land or on snow. ''
Kite landboarding
Kite landboarding, also known as land kiteboarding or flyboarding, is based on the sport of kitesurfing, where a rider on a surf-style board is pulled over water by a kite. Kite landboarding involves the use of a mountain board or landboard, whic ...
'' involves the use of a
mountain board
Mountainboarding, also known as Dirtboarding, Offroad Boarding, and All-Terrain Boarding (ATB), is a well establishedWall Street Journal, April 16th 1998 if little-known action sport, derived from snowboarding. This was initially pioneered by Ja ...
or land board—a
skateboard
A skateboard is a type of sports equipment used for skateboarding. They are usually made of a specially designed 7-8 ply maple plywood deck and polyurethane wheels attached to the underside by a pair of skateboarding trucks.
The skateboarde ...
with large pneumatic wheels and foot-straps. ''
Snow kiting
Snowkiting or kite skiing is an outdoor winter sport where people use kite power to glide on snow or ice. The skier uses a kite to give them power over large jumps. The sport is similar to water-based kiteboarding, but with the footwear used in ...
'' is an outdoor winter sport where people use kite power to glide on a board (or skis) over snow or ice.
Rotor-powered
![Small wind turbine power output](https://upload.wikimedia.org/wikipedia/commons/6/62/Small_wind_turbine_power_output.png)
Rotor-powered vehicles are wind-powered vehicles that use ''rotors''—instead of sails—which may have a shroud around them (
ducted fan
In aeronautics, a ducted fan is a thrust-generating mechanical fan or propeller mounted within a cylindrical duct or shroud. Other terms include ducted propeller or shrouded propeller. When used in vertical takeoff and landing
(VTOL) applicatio ...
) or constitute an unducted
propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
, and which may adjust orientation to face the apparent wind. The rotor may be connected via a drive train to wheels or to a generator that provides electrical power to electric motors that drive the wheels. Other concepts use a
vertical axis wind turbine
A vertical-axis wind turbine (VAWT) is a type of wind turbine where the main rotor shaft is set transverse to the wind while the main components are located at the base of the turbine. This arrangement allows the generator and gearbox to be ...
with airfoils that rotate around a vertical axis.
Theory
A vehicle with a bladed rotor mechanically connected to the wheels can be designed to go at a speed faster than that of the wind, both directly into the wind and directly downwind. Upwind, the rotor works as a
wind turbine
A wind turbine is a device that converts the kinetic energy of wind into electrical energy. Hundreds of thousands of large turbines, in installations known as wind farms, now generate over 650 gigawatts of power, with 60 GW added each year. ...
driving the wheels. Downwind, it works as a
propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
, driven by the wheels. In both cases, power comes from the difference in velocity between the air mass and the ground, as received by the vehicle's rotor or wheels.
Relative to the vehicle, both the air and the ground are passing backwards. However, travelling upwind, the air is coming at the vehicle faster than the ground, whereas travelling downwind faster than the wind speed, the air is coming at the vehicle more slowly than the ground. The vehicle draws power from the faster of the two media in each case and imparts it to the slower of the two: upwind, drawing power from the wind and imparting it to the wheels and, downwind, drawing power from the wheels and imparting it to the rotor—in each case in proportion to the velocity of the medium, relative to the vehicle.
[
In summary:][
* Upwind, the rotor harvests the power from the oncoming air and drives the wheels, as would a wind turbine.
* Downwind, when the vehicle is traveling faster than the windspeed, the ground is the fastest-moving medium relative to the vehicle, so the wheels harvest the power and impart it to the rotor, which propels the vehicle.
How fast a given wind speed can propel a vehicle in either direction is limited only by the efficiency of the turbine blades, losses in the drive train, and the vehicle's ]aerodynamic drag
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fl ...
, apart from the drag of the turbine.
The same principles apply to a watercraft using a wind turbine to drive a screw propeller in the water upwind, or using a water turbine to drive a propeller in the airstream downwind.
Fixed-course vehicles
Several competitions have been held for rotor-powered vehicles. Notable among them is , an event held annually in the Netherlands
)
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. Participating universities build entries to determine the best and fastest wind-powered vehicle.[
] The rules are that the vehicles ride on wheels, with one driver, propelled by a rotor, coupled to the wheels. Temporary storage of energy is allowed, if empty at the beginning of the race. Charging the storage device is counted as race time. Racing takes place towards the wind. Vehicles are judged by their fastest run, innovation, and the results of a series of drag races.[
] In 2008, entrants were from: Stuttgart University
The University of Stuttgart (german: Universität Stuttgart) is a leading research university located in Stuttgart, Germany. It was founded in 1829 and is organized into 10 faculties. It is one of the oldest technical universities in Germany with ...
, the Flensburg University of Applied Sciences, the Energy Research Centre of the Netherlands
The Energy Research Centre of the Netherlands (ECN) is one of the largest energy research institute in Europe and holds a strong international position. With and for the market, ECN develops knowledge and technology that enable a transition to a ...
, the Technical University of Denmark
The Technical University of Denmark ( da, Danmarks Tekniske Universitet), often simply referred to as DTU, is a polytechnic university and school of engineering. It was founded in 1829 at the initiative of Hans Christian Ørsted as Denmark's fi ...
, the University of Applied Sciences
A university of applied sciences (UAS), nowadays much less commonly called a polytechnic university or vocational university, is an institution of higher education and sometimes research that provides vocational education and grants academic de ...
of Kiel and the Christian Albrechts University of Kiel.[ Two top performers have been the "Ventomobile" and ''Spirit of Amsterdam (1 and 2)''.
]
Ventomobile
The Ventomobile was a wind-powered lightweight three-wheeler
A three-wheeler is a vehicle with three wheels. Some are motorized tricycles, which may be legally classed as motorcycles, while others are tricycles without a motor, some of which are human-powered vehicles and animal-powered vehicles.
Overv ...
designed by University of Stuttgart students. It had a carbon-fiber
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
rotor support that was directed into the wind and variably pitched rotor blades that adjust for wind speed. Power transmission between the rotor and the driving wheels was via two bicycle gearboxes and a bicycle chain. It won the first prize at the Racing Aeolus held at Den Helder
Den Helder () is a municipality and a city in the Netherlands, in the province of North Holland. Den Helder occupies the northernmost point of the North Holland peninsula. It is home to the country's main naval base.
From here the Royal TESO fe ...
, Netherlands
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, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
, in August 2008.
''Spirit of Amsterdam''
The wind-powered land vehicles ''Spirit of Amsterdam '' and ''Spirit of Amsterdam 2'' were built by the Hogeschool van Amsterdam (University of Applied Science Amsterdam). In 2009 and 2010 the ''Spirit of Amsterdam'' team won first prize at the Racing Aeolus held in Denmark. The ''Spirit of Amsterdam 2'' was the second vehicle built by the Hogeschool van, Amsterdam. It used a wind turbine to capture the wind velocity and used mechanical power to propel the vehicle against the wind. This vehicle was capable of driving with a wind. An onboard computer automatically shifted gears to achieve optimum performance.
Straight-line vehicles
Some wind-powered vehicles are built solely to demonstrate a limited principle, e.g. the ability to go upwind or downwind ''faster than the prevailing windspeed''.
In 1969, Andrew Bauer—a wind tunnel engineer for the Douglas Aircraft Company
The Douglas Aircraft Company was an American aerospace manufacturer based in Southern California. It was founded in 1921 by Donald Wills Douglas Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas; it then operated as ...
—built and demonstrated a propeller-driven vehicle that could go directly downwind faster than the windspeed, which was recorded in a video. He published the concept in the same year.
In 2006, Jack Goodman published a video of a similar homemade design, describing it as "directly downwind faster than the wind" (DDFTTW). In 2008, Rick Cavallaro—an aerospace engineer
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is si ...
and computer technologist
A computer repair technician is a person who repairs and maintains computers and servers. The technician's responsibilities may extend to include building or configuring new hardware, installing and updating software packages, and creating and ...
—made a toy model based on that design, that fit on a treadmill, and submitted a video of it to the Mythbusters video challenge.
In 2010, Cavallaro built and piloted a wind-driven vehicle, '' Blackbird'', in cooperation with the San Jose State University
San José State University (San Jose State or SJSU) is a public university in San Jose, California. Established in 1857, SJSU is the oldest public university on the West Coast and the founding campus of the California State University (CSU) sys ...
aviation department in a project sponsored by Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
, to demonstrate the feasibility of going directly downwind faster than the wind. He achieved two validated milestones, going both directly ''downwind'' and directly ''upwind'' faster than the speed of the prevailing wind.
*''Downwind''—In 2010, ''Blackbird'' set the world's first certified record for going directly downwind faster than the wind, using only wind power.[ The vehicle achieved a dead downwind speed of about 2.8 times the speed of the wind.] In 2011 a streamlined ''Blackbird'' reached close to 3 times the speed of wind.[
*''Upwind''—In 2012, ''Blackbird'' set the world's first certified record for going directly upwind faster than the wind, using only wind power. The vehicle achieved a dead upwind speed of about 2.1 times the speed of the wind.][
Blackbird has been analyzed a number of times since then, in research papers and on the 2013 International Physics Olympiad, and a working toy model was reconstructed w/ 3d-printing instructions in 2021.]
See also
*High-performance sailing
High-performance sailing is achieved with low forward surface resistance—encountered by catamarans, sailing hydrofoils, iceboats or land sailing craft—as the sailing craft obtains motive power with its sails or aerofoils at speeds that are ofte ...
*Land sailing
Land sailing, also known as sand yachting, land yachting or dirtboating, is the act of moving across land in a wheeled vehicle powered by wind through the use of a sail. The term comes from analogy with (water) sailing. Historically, land saili ...
*Kitesurfing
Kiteboarding or kitesurfing is a sport that involves using wind power with a large power kite to pull a rider across a water, land, or snow surface. It combines aspects of paragliding, surfing, windsurfing, skateboarding, snowboarding, and wak ...
References
External links
Andrew Bauer wind-rotor-powered cart video (1969)
Drag race into the wind, winDTUrbineracer vs. Inventus, Stuttgart
Counterintuitive Performance of Land and Sea Yachts
{{DEFAULTSORT:Wind-Powered Vehicle
Tricycles