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73-470: 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 mph (202.9 km/h). Greenbird , sponsored by Ecotricity , was described as being "a very high performance sailboat". It uses a rigid vertical wing , instead of

146-548: A carbon-fiber 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 , Netherlands , in August 2008. The wind-powered land vehicles Spirit of Amsterdam and Spirit of Amsterdam 2 were built by

219-423: A beach depends on whether the waves are constructive or destructive, and whether the material is sand or shingle. Waves are constructive if the period between their wave crests is long enough for the breaking water to recede and the sediment to settle before the succeeding wave arrives and breaks. Fine sediment transported from lower down the beach profile will compact if the receding water percolates or soaks into

292-409: A beach tends to indicate the energy of the waves and wind in the locality. Constructive waves move material up the beach while destructive waves move the material down the beach. During seasons when destructive waves are prevalent, the shallows will carry an increased load of sediment and organic matter in suspension. On sandy beaches, the turbulent backwash of destructive waves removes material forming

365-463: A filter for runoff from the coastal plain. If the runoff is naturally dispersed along the beach, water borne silt and organic matter will be retained on the land and will feed the flora in the coastal area. Runoff that is dispersed along the beach will tend to percolate through the beach and may emerge from the beach at low tide. The retention of the freshwater may also help to maintain underground water reserves and will resist salt water incursion. If

438-430: 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

511-402: A generator that provides electrical power to electric motors that drive the wheels. Other concepts use a vertical axis wind turbine with airfoils that rotate around a vertical axis. A 1904 version employed a re-purposed rotor from a mass-produced windmill with its gearing connected to driving wheels. A vehicle with a bladed rotor mechanically connected to the wheels can be designed to go at

584-401: A gently sloping beach. On pebble and shingle beaches the swash is dissipated more quickly because the large particle size allows greater percolation , thereby reducing the power of the backwash, and the beach remains steep. Compacted fine sediments will form a smooth beach surface that resists wind and water erosion. During hot calm seasons, a crust may form on the surface of ocean beaches as

657-424: 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 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

730-492: A lesser root ball. Erosion of beaches can expose less resilient soils and rocks to wind and wave action leading to undermining of coastal headlands eventually resulting in catastrophic collapse of large quantities of overburden into the shallows. This material may be distributed along the beach front leading to a change in the habitat as sea grasses and corals in the shallows may be buried or deprived of light and nutrients. Coastal areas settled by man inevitably become subject to

803-465: A necessary and permanent feature of beach maintenance. During beach nourishment activities, care must be taken to place new sediments so that the new sediments compact and stabilize before aggressive wave or wind action can erode them. Material that is concentrated too far down the beach may form a temporary groyne that will encourage scouring behind it. Sediments that are too fine or too light may be eroded before they have compacted or been integrated into

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876-526: A propeller driven vehicle that could travel against the wind. In 1969, Andrew Bauer—a wind tunnel engineer for the Douglas Aircraft Company —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

949-468: A rapid cycle of growth throughout the 1850s and 1860s. The growth was intensified by the practice among the Lancashire cotton mill owners of closing the factories for a week every year to service and repair machinery. These became known as wakes weeks . Each town's mills would close for a different week, allowing Blackpool to manage a steady and reliable stream of visitors over a prolonged period in

1022-461: A screw propeller in the water upwind, or using a water turbine to drive a propeller in the airstream downwind. Several competitions have been held for rotor-powered vehicles. Notable among them is Racing Aeolus  [ nl ] , an event held annually in the Netherlands . Participating universities build entries to determine the best and fastest wind-powered vehicle. The rules are that

1095-435: A shoreline subject to constant erosion and loss of foreshore. This is often required where the flow of new sediment caused by the longshore current has been disrupted by construction of harbors, breakwaters, causeways or boat ramps, creating new current flows that scour the sand from behind these structures and deprive the beach of restorative sediments. If the causes of the erosion are not addressed, beach nourishment can become

1168-460: A speed faster than that of the wind, both directly into the wind and directly downwind. Upwind, the rotor works as a wind turbine driving the wheels. Downwind, it works as a propeller , 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,

1241-422: A tidal surge or tsunami which causes significant coastal flooding , substantial quantities of material may be eroded from the coastal plain or dunes behind the berm by receding water. This flow may alter the shape of the coastline, enlarge the mouths of rivers and create new deltas at the mouths of streams that had not been powerful enough to overcome longshore movement of sediment. The line between beach and dune

1314-883: 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 shells or coralline algae . Sediments settle in different densities and structures, depending on the local wave action and weather , creating different textures, colors and gradients or layers of material. Though some beaches form on inland freshwater locations such as lakes and rivers , most beaches are in coastal areas where wave or current action deposits and reworks sediments. Erosion and changing of beach geologies happens through natural processes, like wave action and extreme weather events . Where wind conditions are correct, beaches can be backed by coastal dunes which offer protection and regeneration for

1387-438: Is a significant source of sand particles. Some species of fish that feed on algae attached to coral outcrops and rocks can create substantial quantities of sand particles over their lifetime as they nibble during feeding, digesting the organic matter , and discarding the rock and coral particles which pass through their digestive tracts. The composition of the beach depends upon the nature and quantity of sediments upstream of

1460-412: 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 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

1533-400: Is an outdoor winter sport where people use kite power to glide on a board (or skis) over snow or ice. Rotor-powered vehicles are wind-powered vehicles that use rotors —instead of sails—which may have a shroud around them ( ducted fan ) or constitute an unducted propeller , and which may adjust orientation to face the apparent wind. The rotor may be connected via a drive train to wheels or to

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1606-413: Is best suited for windy flat areas; races often take place on beaches , airfields , and dry lake beds in desert regions. Records for sail-powered vehicles have been set on land, as follows: 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

1679-452: Is difficult to define in the field. Over any significant period of time, sediment is always being exchanged between them. The drift line (the high point of material deposited by waves) is one potential demarcation. This would be the point at which significant wind movement of sand could occur, since the normal waves do not wet the sand beyond this area. However, the drift line is likely to move inland under assault by storm waves. Beaches are

1752-455: Is the importing and deposition of sand or other sediments in an effort to restore a beach that has been damaged by erosion. Beach nourishment often involves excavation of sediments from riverbeds or sand quarries. This excavated sediment may be substantially different in size and appearance to the naturally occurring beach sand. In extreme cases, beach nourishment may involve placement of large pebbles or rocks in an effort to permanently restore

1825-622: 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

1898-853: The Flensburg University of Applied Sciences , the Energy Research Centre of the Netherlands , the Technical University of Denmark , the University of Applied Sciences of Kiel and the Christian Albrechts University of Kiel. Two top performers have been the "Ventomobile" and Spirit of Amsterdam (1 and 2) . The Ventomobile was a wind-powered lightweight three-wheeler designed by University of Stuttgart students. It had

1971-452: The seashore is most commonly associated with the word beach , beaches are also found by lakes and alongside large rivers. Beach may refer to: The former are described in detail below; the larger geological units are discussed elsewhere under bars . There are several conspicuous parts to a beach that relate to the processes that form and shape it. The part mostly above water (depending upon tide), and more or less actively influenced by

2044-487: The 1720s; it had been a fashionable spa town since a stream of acidic water was discovered running from one of the cliffs to the south of the town in the 17th century. The first rolling bathing machines were introduced by 1735. The opening of the resort in Brighton and its reception of royal patronage from King George IV , extended the seaside as a resort for health and pleasure to the much larger London market, and

2117-417: 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

2190-422: The air, all of which are beyond the scope of this article. 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. Aerodynamic forces on sails depend on wind speed and direction and the speed and direction of

2263-439: 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 sailing has evolved from a novelty into a sport, since the 1950s. The vehicles used in sailing are known as land or sand yachts . They typically have three (sometimes four) wheels, which are steered by pedals or hand levers from a sitting or lying position. Land sailing

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2336-435: The beach and into the sea. If the flow is constant, runoff from cleared land arriving at the beach head will tend to deposit this material into the sand changing its color, odor and fauna. The concentration of pedestrian and vehicular traffic accessing the beach for recreational purposes may cause increased erosion at the access points if measures are not taken to stabilize the beach surface above high-water mark. Recognition of

2409-457: The beach as a popular leisure resort from the mid-19th century was the first manifestation of what is now the global tourist industry. The first seaside resorts were opened in the 18th century for the aristocracy, who began to frequent the seaside as well as the then fashionable spa towns, for recreation and health. One of the earliest such seaside resorts, was Scarborough in Yorkshire during

2482-620: The beach became a centre for upper-class pleasure and frivolity. This trend was praised and artistically elevated by the new romantic ideal of the picturesque landscape; Jane Austen 's unfinished novel Sanditon is an example of that. Later, Queen Victoria 's long-standing patronage of the Isle of Wight and Ramsgate in Kent ensured that a seaside residence was considered as a highly fashionable possession for those wealthy enough to afford more than one home. The extension of this form of leisure to

2555-401: The beach head, they may erode the beach creating a lagoon or delta. Dense vegetation tends to absorb rainfall reducing the speed of runoff and releasing it over longer periods of time. Destruction by burning or clearance of the natural vegetation tends to increase the speed and erosive power of runoff from rainfall. This runoff will tend to carry more silt and organic matter from the land onto

2628-523: The beach profile is higher in summer. The gentle wave action during this season tends to transport sediment up the beach towards the berm where it is deposited and remains while the water recedes. Onshore winds carry it further inland forming and enhancing dunes. Conversely, the beach profile is lower in the storm season (winter in temperate areas) due to the increased wave energy, and the shorter periods between breaking wave crests. Higher energy waves breaking in quick succession tend to mobilise sediment from

2701-404: The beach, and the speed of flow and turbidity of water and wind. Sediments are moved by moving water and wind according to their particle size and state of compaction. Particles tend to settle and compact in still water. Once compacted, they are more resistant to erosion . Established vegetation (especially species with complex network root systems) will resist erosion by slowing the fluid flow at

2774-1686: The beach. However, these natural forces have become more extreme due to climate change , permanently altering beaches at very rapid rates. Some estimates describe as much as 50 percent of the earth's sandy beaches disappearing by 2100 due to climate-change driven sea level rise. Sandy beaches occupy about one third of global coastlines. These beaches are popular for recreation , playing important economic and cultural roles—often driving local tourism industries. To support these uses, some beaches have human-made infrastructure, such as lifeguard posts, changing rooms , showers, shacks and bars. They may also have hospitality venues (such as resorts, camps, hotels, and restaurants) nearby or housing, both for permanent and seasonal residents. Human forces have significantly changed beaches globally: direct impacts include bad construction practices on dunes and coastlines, while indirect human impacts include water pollution , plastic pollution and coastal erosion from sea level rise and climate change . Some coastal management practices are designed to preserve or restore natural beach processes, while some beaches are actively restored through practices like beach nourishment . Wild beaches, also known as undeveloped or undiscovered beaches, are not developed for tourism or recreation. Preserved beaches are important biomes with important roles in aquatic or marine biodiversity, such as for breeding grounds for sea turtles or nesting areas for seabirds or penguins . Preserved beaches and their associated dune are important for protection from extreme weather for inland ecosystems and human infrastructure. Although

2847-413: The beach. Compacted sediment is more resistant to movement by turbulent water from succeeding waves. Conversely, waves are destructive if the period between the wave crests is short. Sediment that remains in suspension when the following wave crest arrives will not be able to settle and compact and will be more susceptible to erosion by longshore currents and receding tides. The nature of sediments found on

2920-452: The character of underwater flora and fauna in the coastal shallows. Burning or clearance of vegetation on the land adjacent to the beach head, for farming and residential development, changes the surface wind patterns, and exposes the surface of the beach to wind erosion. Farming and residential development are also commonly associated with changes in local surface water flows. If these flows are concentrated in stormwater drains emptying onto

2993-416: The conventional sail, to generate thrust, in the same manner that the wing of an aeroplane generates lift. The only metal in the vehicle is in the wheels and the wing bearings; the remainder is made of carbon composite materials . The vehicle weighs about six hundred kilograms. According to Jenkins, the light weight and aerodynamic shape of the vehicle allows it to attain speeds three to five times faster than

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3066-474: 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 . The speed of the craft at a given point of sail contributes to the apparent wind ( 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

3139-444: The dangers of loss of beach front flora has caused many local authorities responsible for managing coastal areas to restrict beach access points by physical structures or legal sanctions, and fence off foredunes in an effort to protect the flora. These measures are often associated with the construction of structures at these access points to allow traffic to pass over or through the dunes without causing further damage. Beaches provide

3212-420: The direction of the apparent wind—and lift —the force component normal (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

3285-408: 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 or tethers to which the kite is attached, thereby powering the vehicle. A kite buggy is a light, purpose-built vehicle powered by a power kite . It is single-seated and has one steerable front wheel and two fixed rear wheels. The driver sits in

3358-504: The effects of human-made structures and processes. Over long periods of time, these influences may substantially alter the shape of the coastline, and the character of the beach. Beachfront flora plays a major role in stabilizing the foredunes and preventing beach head erosion and inland movement of dunes. If flora with network root systems (creepers, grasses, and palms) are able to become established, they provide an effective coastal defense as they trap sand particles and rainwater and enrich

3431-434: The established vegetation. Foreign unwashed sediments may introduce flora or fauna that are not usually found in that locality. Brighton Beach, on the south coast of England, is a shingle beach that has been nourished with very large pebbles in an effort to withstand the erosion of the upper area of the beach. These large pebbles made the beach unwelcoming for pedestrians for a period of time until natural processes integrated

3504-444: 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. 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. Beach A beach

3577-417: The feature. Where wind is the force distributing the grains inland, the deposit behind the beach becomes a dune . These geomorphic features compose what is called the beach profile . The beach profile changes seasonally due to the change in wave energy experienced during summer and winter months. In temperate areas where summer is characterised by calmer seas and longer periods between breaking wave crests,

3650-450: The heat of the sun evaporates the water leaving the salt which crystallises around the sand particles. This crust forms an additional protective layer that resists wind erosion unless disturbed by animals or dissolved by the advancing tide. Cusps and horns form where incoming waves divide, depositing sand as horns and scouring out sand to form cusps. This forms the uneven face on some sand shorelines . White sand beaches look white because

3723-449: The height of the water table. Some flora naturally occurring on the beach head requires freshwater runoff from the land. Diversion of freshwater runoff into drains may deprive these plants of their water supplies and allow sea water incursion, increasing the saltiness of the groundwater. Species that are not able to survive in salt water may die and be replaced by mangroves or other species adapted to salty environments. Beach nourishment

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3796-445: The middle and working classes began with the development of the railways in the 1840s, which offered cheap fares to fast-growing resort towns. In particular, the completion of a branch line to the small seaside town of Blackpool from Poulton led to a sustained economic and demographic boom. A sudden influx of visitors, arriving by rail, led entrepreneurs to build accommodation and create new attractions, leading to more visitors and

3869-632: The naturally occurring shingle into the pebble base. Even in Roman times, wealthy people spent their free time on the coast. They also built large villa complexes with bathing facilities (so-called maritime villas) in particularly beautiful locations. Excavations of Roman architecture can still be found today, for example on the Amalfi Coast near Naples and in Barcola in Trieste. The development of

3942-621: The permanent water forming offshore bars, lagoons or increasing the area of the beach exposed at low tide. Large and rapid movements of exposed sand can bury and smother flora in adjacent areas, aggravating the loss of habitat for fauna, and enlarging the area of instability. If there is an adequate supply of sand, and weather conditions do not allow vegetation to recover and stabilize the sediment, wind-blown sand can continue to advance, engulfing and permanently altering downwind landscapes. Sediment moved by waves or receding floodwaters can be deposited in coastal shallows, engulfing reed beds and changing

4015-564: The quartz or eroded limestone in the sand reflects or scatters sunlight without absorbing other colors. The composition of the sand varies depending on the local minerals and geology. Some of the types of sand found in beaches around the world are: Beaches are changed in shape chiefly by the movement of water and wind. Any weather event that is associated with turbid or fast-flowing water or high winds will erode exposed beaches. Longshore currents will tend to replenish beach sediments and repair storm damage. Tidal waterways generally change

4088-415: The result of wave action by which waves or currents move sand or other loose sediments of which the beach is made as these particles are held in suspension . Alternatively, sand may be moved by saltation (a bouncing movement of large particles). Beach materials come from erosion of rocks offshore, as well as from headland erosion and slumping producing deposits of scree . A coral reef offshore

4161-416: The rotor—in each case in proportion to the velocity of the medium, relative to the vehicle. In summary: 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 , apart from the drag of the turbine. The same principles apply to a watercraft using a wind turbine to drive

4234-445: 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 110 kilometres per hour (68 mph). Kite boards of different description are used on dry land or on snow. Kite landboarding involves the use of a mountain board or land board—a skateboard with large pneumatic wheels and foot-straps. Snow kiting

4307-412: The shallows, keeping it in suspension where it is prone to be carried along the beach by longshore currents, or carried out to sea to form longshore bars, especially if the longshore current meets an outflow from a river or flooding stream. The removal of sediment from the beach berm and dune thus decreases the beach profile. If storms coincide with unusually high tides, or with a freak wave event such as

4380-487: The shape of their adjacent beaches by small degrees with every tidal cycle. Over time these changes can become substantial leading to significant changes in the size and location of the beach. Changes in the shape of the beach may undermine the roots of large trees and other flora. Many beach adapted species (such as coconut palms) have a fine root system and large root ball which tends to withstand wave and wind action and tends to stabilize beaches better than other trees with

4453-562: The shape, profile and location of a beach within hours. Destruction of flora on the berm by the use of herbicides, excessive pedestrian or vehicle traffic, or disruption to freshwater flows may lead to erosion of the berm and dunes. While the destruction of flora may be a gradual process that is imperceptible to regular beach users, it often becomes immediately apparent after storms associated with high winds and freak wave events that can rapidly move large volumes of exposed and unstable sand, depositing them further inland, or carrying them out into

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4526-561: The speed of the wind . Greenbird is the fifth in a series of wind-powered land vehicles that Jenkins had constructed in his efforts to break the speed record. Jenkins said he had been trying to break the record for the past ten years in different locations, such as Australia , Britain , and the United States , but weather conditions were not suitable for him to reach maximum speeds. Wind-powered vehicle Rotor-powered examples have demonstrated ground speeds that exceed that of

4599-577: The summer. A prominent feature of the resort was the promenade and the pleasure piers , where an eclectic variety of performances vied for the people's attention. In 1863, the North Pier in Blackpool was completed, rapidly becoming a centre of attraction for upper class visitors. Central Pier was completed in 1868, with a theatre and a large open-air dance floor. Many of the popular beach resorts were equipped with bathing machines , because even

4672-425: The surface flow of the runoff is diverted and concentrated by drains that create constant flows over the beach above the sea or river level, the beach will be eroded and ultimately form an inlet unless longshore flows deposit sediments to repair the breach. Once eroded, an inlet may allow tidal inflows of salt water to pollute areas inland from the beach and may also affect the quality of underground water supplies and

4745-519: The surface layer of the dunes, allowing other plant species to become established. They also protect the berm from erosion by high winds, freak waves and subsiding floodwaters. Over long periods of time, well-stabilized foreshore areas will tend to accrete, while unstabilized foreshores will tend to erode, leading to substantial changes in the shape of the coastline. These changes usually occur over periods of many years. Freak wave events such as tsunami, tidal waves, and storm surges may substantially alter

4818-657: The surface layer. When affected by moving water or wind, particles that are eroded and held in suspension will increase the erosive power of the fluid that holds them by increasing the average density, viscosity, and volume of the moving fluid. Coastlines facing very energetic wind and wave systems will tend to hold only large rocks as smaller particles will be held in suspension in the turbid water column and carried to calmer areas by longshore currents and tides. Coastlines that are protected from waves and winds will tend to allow finer sediments such as clay and mud to precipitate creating mud flats and mangrove forests. The shape of

4891-412: 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 ,

4964-408: The waves at some point in the tide, is termed the beach berm. The berm is the deposit of material comprising the active shoreline. The berm has a crest (top) and a face —the latter being the slope leading down towards the water from the crest. At the very bottom of the face, there may be a trough , and further seaward one or more long shore bars: slightly raised, underwater embankments formed where

5037-434: The waves first start to break. The sand deposit may extend well inland from the berm crest , where there may be evidence of one or more older crests (the storm beach ) resulting from very large storm waves and beyond the influence of the normal waves. At some point the influence of the waves (even storm waves) on the material comprising the beach stops, and if the particles are small enough (sand size or smaller), winds shape

5110-565: The wind" (DDFTTW). In 2008, Rick Cavallaro—an aerospace engineer and computer technologist —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 aviation department in a project sponsored by Google , to demonstrate

5183-420: 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 , with a recorded top speed of 202.9 kilometres per hour (126.1 mph). Other wind-powered conveyances include sailing vessels that travel on water, and balloons and sailplanes that travel in

5256-650: 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 good conditions. International DN iceboats often achieve speeds of 48 knots (89 km/h; 55 mph) while racing, and speeds as high as 59 knots (109 km/h; 68 mph) have been recorded. Kite -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. A kite

5329-415: Was capable of driving 6.6 metres per second (15 mph) with a 10 metres per second (22 mph) wind. An onboard computer automatically shifted gears to achieve optimum performance. 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 1904 George Phillips of Webster, South Dakota demonstrated

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