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64-553: Happy Isles is located where the slope of the Merced River changes from the much steeper upper main stem to the essentially flat Valley floor. At Happy Isles, the river gradient is approximately 2%. The gradient of the Merced River at Happy Isles is steeper than in the Valley floor, and the channel of the river is cut into erosion -resistant granitic boulders and talus materials, compared to channel deposits of sands and gravel present on

128-582: A south-pointing chariot , a vehicle with an early form of guidance system. The stagecoach , a four-wheeled vehicle drawn by horses, originated in 13th century England. Railways began reappearing in Europe after the Dark Ages . The earliest known record of a railway in Europe from this period is a stained-glass window in the Minster of Freiburg im Breisgau dating from around 1350. In 1515, Cardinal Matthäus Lang wrote

192-504: A wagonway , a predecessor of the railway, found so far was the 6 to 8.5 km (4 to 5 mi) long Diolkos wagonway, which transported boats across the Isthmus of Corinth in Greece since around 600 BC. Wheeled vehicles pulled by men and animals ran in grooves in limestone , which provided the track element, preventing the wagons from leaving the intended route. In 200 CE, Ma Jun built

256-432: A 45 degree slope a 71 percent grade instead of a 100 percent. But in practice the usual way to calculate slope is to measure the distance along the slope and the vertical rise, and calculate the horizontal run from that, in order to calculate the grade (100% × rise/run) or standard slope (rise/run). When the angle of inclination is small, using the slope length rather than the horizontal displacement (i.e., using

320-433: A boost from high altitude winds. Compressed gas is currently an experimental method of storing energy. In this case, compressed gas is simply stored in a tank and released when necessary. Like elastics, they have hysteresis losses when gas heats up during compression. Gravitational potential energy is a form of energy used in gliders, skis, bobsleds and numerous other vehicles that go down hill. Regenerative braking

384-577: A description of the Reisszug , a funicular railway at the Hohensalzburg Fortress in Austria. The line originally used wooden rails and a hemp haulage rope and was operated by human or animal power, through a treadwheel . 1769: Nicolas-Joseph Cugnot is often credited with building the first self-propelled mechanical vehicle or automobile in 1769. In Russia, in the 1780s, Ivan Kulibin developed

448-846: A fact that the New York Times denied in error . Rocket engines can be particularly simple, sometimes consisting of nothing more than a catalyst, as in the case of a hydrogen peroxide rocket. This makes them an attractive option for vehicles such as jet packs. Despite their simplicity, rocket engines are often dangerous and susceptible to explosions. The fuel they run off may be flammable, poisonous, corrosive or cryogenic. They also suffer from poor efficiency. For these reasons, rocket engines are only used when absolutely necessary. Electric motors are used in electric vehicles such as electric bicycles , electric scooters, small boats, subways, trains , trolleybuses , trams and experimental aircraft . Electric motors can be very efficient: over 90% efficiency

512-665: A flight with an actual ornithopter on July 31, 2010. Paddle wheels are used on some older watercraft and their reconstructions. These ships were known as paddle steamers . Because paddle wheels simply push against the water, their design and construction is very simple. The oldest such ship in scheduled service is the Skibladner . Many pedalo boats also use paddle wheels for propulsion. Screw-propelled vehicles are propelled by auger -like cylinders fitted with helical flanges. Because they can produce thrust on both land and water, they are commonly used on all-terrain vehicles. The ZiL-2906

576-423: A gas station. Fuel cells are similar to batteries in that they convert from chemical to electrical energy, but have their own advantages and disadvantages. Electrified rails and overhead cables are a common source of electrical energy on subways, railways, trams, and trolleybuses. Solar energy is a more modern development, and several solar vehicles have been successfully built and tested, including Helios ,

640-463: A go around is needed. Parachutes are used to slow down vehicles travelling very fast. Parachutes have been used in land, air and space vehicles such as the ThrustSSC , Eurofighter Typhoon and Apollo Command Module . Some older Soviet passenger jets had braking parachutes for emergency landings. Boats use similar devices called sea anchors to maintain stability in rough seas. To further increase

704-509: A hot exhaust. Trains using turbines are called gas turbine-electric locomotives . Examples of surface vehicles using turbines are M1 Abrams , MTT Turbine SUPERBIKE and the Millennium . Pulse jet engines are similar in many ways to turbojets but have almost no moving parts. For this reason, they were very appealing to vehicle designers in the past; however, their noise, heat, and inefficiency have led to their abandonment. A historical example of

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768-537: A human-pedalled, three-wheeled carriage with modern features such as a flywheel , brake , gear box and bearings ; however, it was not developed further. In 1783, the Montgolfier brothers developed the first balloon vehicle. In 1801, Richard Trevithick built and demonstrated his Puffing Devil road locomotive, which many believe was the first demonstration of a steam-powered road vehicle, though it could not maintain sufficient steam pressure for long periods and

832-584: A solar-powered aircraft. Nuclear power is a more exclusive form of energy storage, currently limited to large ships and submarines, mostly military. Nuclear energy can be released by a nuclear reactor , nuclear battery , or repeatedly detonating nuclear bombs . There have been two experiments with nuclear-powered aircraft, the Tupolev Tu-119 and the Convair X-6 . Mechanical strain is another method of storing energy, whereby an elastic band or metal spring

896-407: A special arrangement in which all four main wheels can be angled. Skids can also be used to steer by angling them, as in the case of a snowmobile . Ships, boats, submarines, dirigibles and aeroplanes usually have a rudder for steering. On an airplane, ailerons are used to bank the airplane for directional control, sometimes assisted by the rudder. With no power applied, most vehicles come to

960-411: A stop due to friction . But it is often required to stop a vehicle faster than by friction alone, so almost all vehicles are equipped with a braking system. Wheeled vehicles are typically equipped with friction brakes, which use the friction between brake pads (stators) and brake rotors to slow the vehicle. Many airplanes have high-performance versions of the same system in their landing gear for use on

1024-489: A vacuum, which limits their use to spaceborne vehicles. Ion thrusters run primarily off electricity, but they also need a propellant such as caesium , or, more recently xenon . Ion thrusters can achieve extremely high speeds and use little propellant; however, they are power-hungry. The mechanical energy that motors and engines produce must be converted to work by wheels, propellers, nozzles, or similar means. Aside from converting mechanical energy into motion, wheels allow

1088-422: A variety of conditions. One of the difficulties met when using gas motors is the cooling effect of expanding gas. These engines are limited by how quickly they absorb heat from their surroundings. The cooling effect can, however, double as air conditioning. Compressed gas motors also lose effectiveness with falling gas pressure. Ion thrusters are used on some satellites and spacecraft. They are only effective in

1152-680: A vehicle can ascend while maintaining a particular speed is sometimes termed that vehicle's "gradeability" (or, less often, "grade ability"). The lateral slopes of a highway geometry are sometimes called fills or cuts where these techniques have been used to create them. In the United States, the maximum grade for federally funded highways is specified in a design table based on terrain and design speeds, with up to 6% generally allowed in mountainous areas and hilly urban areas with exceptions for up to 7% grades on mountainous roads with speed limits below 60 mph (95 km/h). The steepest roads in

1216-528: A vehicle to roll along a surface and, with the exception of railed vehicles, to be steered. Wheels are ancient technology, with specimens being discovered from over 5000 years ago. Wheels are used in a plethora of vehicles, including motor vehicles, armoured personnel carriers , amphibious vehicles, airplanes, trains, skateboards and wheelbarrows. Nozzles are used in conjunction with almost all reaction engines. Vehicles using nozzles include jet aircraft, rockets, and personal watercraft . While most nozzles take

1280-400: A vehicle's steering through the gyroscopic effect . They have been used experimentally in gyrobuses . Wind energy is used by sailboats and land yachts as the primary source of energy. It is very cheap and fairly easy to use, the main issues being dependence on weather and upwind performance. Balloons also rely on the wind to move horizontally. Aircraft flying in the jet stream may get

1344-405: Is fuel . External combustion engines can use almost anything that burns as fuel, whilst internal combustion engines and rocket engines are designed to burn a specific fuel, typically gasoline, diesel or ethanol . Food is the fuel used to power non-motor vehicles such as cycles, rickshaws and other pedestrian-controlled vehicles. Another common medium for storing energy is batteries , which have

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1408-730: Is 23.1% by the 67-Bernal Heights on Alabama Street between Ripley and Esmeralda Streets. Likewise, the Pittsburgh Department of Engineering and Construction recorded a grade of 37% (20°) for Canton Avenue. The street has formed part of a bicycle race since 1983. Grade, pitch, and slope are important components in landscape design , garden design , landscape architecture , and architecture ; for engineering and aesthetic design factors. Drainage, slope stability, circulation of people and vehicles, complying with building codes, and design integration are all aspects of slope considerations in environmental design . Ruling gradients limit

1472-465: Is a stub . You can help Misplaced Pages by expanding it . Grade (slope) The grade (US) or gradient (UK) (also called stepth , slope , incline , mainfall , pitch or rise ) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal . It is a special case of the slope , where zero indicates horizontality . A larger number indicates higher or steeper degree of "tilt". Often slope

1536-519: Is an example of capturing kinetic energy where the brakes of a vehicle are augmented with a generator or other means of extracting energy. When needed, the energy is taken from the source and consumed by one or more motors or engines. Sometimes there is an intermediate medium, such as the batteries of a diesel submarine. Most motor vehicles have internal combustion engines . They are fairly cheap, easy to maintain, reliable, safe and small. Since these engines burn fuel, they have long ranges but pollute

1600-531: Is calculated as a ratio of "rise" to "run", or as a fraction ("rise over run") in which run is the horizontal distance (not the distance along the slope) and rise is the vertical distance. Slopes of existing physical features such as canyons and hillsides, stream and river banks , and beds are often described as grades, but typically the word "grade" is used for human-made surfaces such as roads, landscape grading, roof pitches , railroads , aqueducts , and pedestrian or bicycle routes. The grade may refer to

1664-478: Is common. Electric motors can also be built to be powerful, reliable, low-maintenance and of any size. Electric motors can deliver a range of speeds and torques without necessarily using a gearbox (although it may be more economical to use one). Electric motors are limited in their use chiefly by the difficulty of supplying electricity. Compressed gas motors have been used on some vehicles experimentally. They are simple, efficient, safe, cheap, reliable and operate in

1728-414: Is deformed and releases energy as it is allowed to return to its ground state. Systems employing elastic materials suffer from hysteresis , and metal springs are too dense to be useful in many cases. Flywheels store energy in a spinning mass. Because a light and fast rotor is energetically favorable, flywheels can pose a significant safety hazard. Moreover, flywheels leak energy fairly quickly and affect

1792-438: Is desirable and important in supplying traction to facilitate motion on land. Most land vehicles rely on friction for accelerating, decelerating and changing direction. Sudden reductions in traction can cause loss of control and accidents. Most vehicles, with the notable exception of railed vehicles, have at least one steering mechanism. Wheeled vehicles steer by angling their front or rear wheels. The B-52 Stratofortress has

1856-654: Is expressed as a percentage, the angle can be determined as: If the angle is expressed as a ratio (1 in n) then: For degrees, percentage (%) and per-mille (‰) notations, larger numbers are steeper slopes. For ratios, larger numbers n of 1 in n are shallower, easier slopes. The examples show round numbers in one or more of the notations and some documented and reasonably well known instances. In vehicular engineering , various land -based designs ( automobiles , sport utility vehicles , trucks , trains , etc.) are rated for their ability to ascend terrain . Trains typically rate much lower than automobiles. The highest grade

1920-518: Is never empty , a propeller could be made to work in space. Similarly to propeller vehicles, some vehicles use wings for propulsion. Sailboats and sailplanes are propelled by the forward component of lift generated by their sails/wings. Ornithopters also produce thrust aerodynamically. Ornithopters with large rounded leading edges produce lift by leading-edge suction forces. Research at the University of Toronto Institute for Aerospace Studies lead to

1984-577: Is restricted to tip jet helicopters and high speed aircraft such as the Lockheed SR-71 Blackbird . Rocket engines are primarily used on rockets, rocket sleds and experimental aircraft. Rocket engines are extremely powerful. The heaviest vehicle ever to leave the ground, the Saturn V rocket, was powered by five F-1 rocket engines generating a combined 180 million horsepower (134.2 gigawatt). Rocket engines also have no need to "push off" anything,

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2048-497: Is the most-produced helicopter. The top commercial jet airliner is the Boeing 737 , at about 10,000 in 2018. At around 14,000 for both, the most produced trams are the KTM-5 and Tatra T3 . The most common trolleybus is ZiU-9 . Locomotion consists of a means that allows displacement with little opposition, a power source to provide the required kinetic energy and a means to control

2112-400: The longitudinal slope or the perpendicular cross slope . There are several ways to express slope: Any of these may be used. Grade is usually expressed as a percentage, but this is easily converted to the angle α by taking the inverse tangent of the standard mathematical slope, which is rise / run or the grade / 100. If one looks at red numbers on the chart specifying grade, one can see

2176-459: The Great Western main line, nicknamed Brunel's Billiard Table, because the early locomotives (and their brakes) were feeble. Steep gradients were concentrated in short sections of lines where it was convenient to employ assistant engines or cable haulage , such as the 1.2 kilometres (0.75 miles) section from Euston to Camden Town . Extremely steep gradients require the use of cables (such as

2240-618: The Guinness Book. Drawing on the U.S. National Elevation Dataset, 7x7 (magazine) identified ten blocks of public streets in San Francisco open to vehicular traffic in the city with grades over 30 percent. The steepest at 41 percent is the block of Bradford Street above Tompkins Avenue in the Bernal Heights neighborhood. The San Francisco Municipal Railway operates bus service among the city's hills . The steepest grade for bus operations

2304-666: The Scenic Railway at Katoomba Scenic World , Australia, with a maximum grade of 122% (52°), claimed to be the world's steepest passenger-carrying funicular ) or some kind of rack railway (such as the Pilatus railway in Switzerland, with a maximum grade of 48% (26°), claimed to be the world's steepest rack railway ) to help the train ascend or descend. Gradients can be expressed as an angle, as feet per mile, feet per chain, 1 in n , x % or y per mille. Since designers like round figures,

2368-489: The Valley floor. The steeper gradient and composition of streambed materials together impede meandering patterns from developing in this area. The area near Happy Isles sustained damage in 1996 during a rockslide . A number of signposts near the Isles are dedicated to the rockfall. This Yosemite -related article is a stub . You can help Misplaced Pages by expanding it . This Mariposa County, California –related article

2432-863: The advantages of being responsive, useful in a wide range of power levels, environmentally friendly, efficient, simple to install, and easy to maintain. Batteries also facilitate the use of electric motors, which have their own advantages. On the other hand, batteries have low energy densities, short service life, poor performance at extreme temperatures, long charging times, and difficulties with disposal (although they can usually be recycled). Like fuel, batteries store chemical energy and can cause burns and poisoning in event of an accident. Batteries also lose effectiveness with time. The issue of charge time can be resolved by swapping discharged batteries with charged ones; however, this incurs additional hardware costs and may be impractical for larger batteries. Moreover, there must be standard batteries for battery swapping to work at

2496-458: The air, causing harmful acid rain . While intermittent internal combustion engines were once the primary means of aircraft propulsion, they have been largely superseded by continuous internal combustion engines, such as gas turbines . Turbine engines are light and, particularly when used on aircraft, efficient. On the other hand, they cost more and require careful maintenance. They can also be damaged by ingesting foreign objects, and they produce

2560-417: The aircraft when retracted. Reverse thrust is also used in many aeroplane engines. Propeller aircraft achieve reverse thrust by reversing the pitch of the propellers, while jet aircraft do so by redirecting their engine exhausts forward. On aircraft carriers , arresting gears are used to stop an aircraft. Pilots may even apply full forward throttle on touchdown, in case the arresting gear does not catch and

2624-410: The environment. A related engine is the external combustion engine . An example of this is the steam engine. Aside from fuel, steam engines also need water, making them impractical for some purposes. Steam engines also need time to warm up, whereas IC engines can usually run right after being started, although this may not be recommended in cold conditions. Steam engines burning coal release sulfur into

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2688-625: The first large-scale rocket program. The Opel RAK.1 became the first rocket car ; the following year, it also became the first rocket-powered aircraft . In 1961, the Soviet space program 's Vostok 1 carried Yuri Gagarin into space. In 1969, NASA 's Apollo 11 achieved the first Moon landing . In 2010, the number of motor vehicles in operation worldwide surpassed 1 billion, roughly one for every seven people. There are over 1 billion bicycles in use worldwide. In 2002 there were an estimated 590 million cars and 205 million motorcycles in service in

2752-650: The first sustained, controlled, reproducible flights. In 1903, the Wright brothers flew the Wright Flyer , the first controlled, powered aircraft, in Kitty Hawk, North Carolina . In 1907, Gyroplane No.I became the first tethered rotorcraft to fly. The same year, the Cornu helicopter became the first rotorcraft to achieve free flight. In 1928, Opel initiated the Opel-RAK program,

2816-1016: The gradient through the platform was eased from 1 in 80 to 1 in 130. Vehicle A vehicle (from Latin vehiculum ) is a machine designed for self- propulsion , usually to transport people, cargo , or both. The term "vehicle" typically refers to land vehicles such as human-powered vehicles (e.g. bicycles , tricycles , velomobiles ), animal-powered transports (e.g. horse-drawn carriages / wagons , ox carts , dog sleds ), motor vehicles (e.g. motorcycles , cars , trucks , buses , mobility scooters ) and railed vehicles ( trains , trams and monorails ), but more broadly also includes cable transport ( cable cars and elevators ), watercraft ( ships , boats and underwater vehicles ), amphibious vehicles (e.g. screw-propelled vehicles , hovercraft , seaplanes ), aircraft ( airplanes , helicopters , gliders and aerostats ) and space vehicles ( spacecraft , spaceplanes and launch vehicles ). This article primarily concerns

2880-418: The ground. A Boeing 757 brake, for example, has 3 stators and 4 rotors. The Space Shuttle also uses frictional brakes on its wheels. As well as frictional brakes, hybrid and electric cars, trolleybuses and electric bicycles can also use regenerative brakes to recycle some of the vehicle's potential energy. High-speed trains sometimes use frictionless Eddy-current brakes ; however, widespread application of

2944-457: The horizontal run by using the Pythagorean theorem, after which it is trivial to calculate the (standard math) slope or the grade (percentage). In Europe, road gradients are signed as a percentage. Grades are related using the following equations with symbols from the figure at top. The slope expressed as a percentage can similarly be determined from the tangent of the angle: If the tangent

3008-539: The load that a locomotive can haul, including the weight of the locomotive itself. On a 1% gradient (1 in 100) a locomotive can pull half (or less) of the load that it can pull on level track. (A heavily loaded train rolling at 20 km/h on heavy rail may require ten times the pull on a 1% upgrade that it does on the level at that speed.) Early railways in the United Kingdom were laid out with very gentle gradients, such as 0.07575% (1 in 1320) and 0.1515% (1 in 660) on

3072-747: The method of expression can affect the gradients selected. The steepest railway lines that do not use a rack system include: Gradients on sharp curves are effectively a bit steeper than the same gradient on straight track, so to compensate for this and make the ruling grade uniform throughout, the gradient on those sharp curves should be reduced slightly. In the era before they were provided with continuous brakes , whether air brakes or vacuum brakes , steep gradients made it extremely difficult for trains to stop safely. In those days, for example, an inspector insisted that Rudgwick railway station in West Sussex be regraded. He would not allow it to open until

3136-614: The more ubiquitous land vehicles, which can be broadly classified by the type of contact interface with the ground : wheels , tracks , rails or skis , as well as the non-contact technologies such as maglev . ISO 3833-1977 is the international standard for road vehicle types, terms and definitions. It is estimated by historians that boats have been used since prehistory ; rock paintings depicting boats, dated from around 50,000 to 15,000 BC, were found in Australia . The oldest boats found by archaeological excavation are logboats , with

3200-483: The motion, such as a brake and steering system. By far, most vehicles use wheels which employ the principle of rolling to enable displacement with very little rolling friction . It is essential that a vehicle have a source of energy to drive it. Energy can be extracted from external sources, as in the cases of a sailboat , a solar-powered car , or an electric streetcar that uses overhead lines. Energy can also be stored, provided it can be converted on demand and

3264-683: The oldest logboat found, the Pesse canoe found in a bog in the Netherlands, being carbon dated to 8040–7510 BC, making it 9,500–10,000 years old, A 7,000 year-old seagoing boat made from reeds and tar has been found in Kuwait. Boats were used between 4000 -3000 BC in Sumer , ancient Egypt and in the Indian Ocean. There is evidence of camel pulled wheeled vehicles about 4000–3000 BC. The earliest evidence of

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3328-466: The propeller has been tested on many terrestrial vehicles, including the Schienenzeppelin train and numerous cars. In modern times, propellers are most prevalent on watercraft and aircraft, as well as some amphibious vehicles such as hovercraft and ground-effect vehicles . Intuitively, propellers cannot work in space as there is no working fluid; however, some sources have suggested that since space

3392-429: The quirkiness of using the grade to specify slope; the numbers go from 0 for flat, to 100% at 45 degrees, to infinity as it approaches vertical. Slope may still be expressed when the horizontal run is not known: the rise can be divided by the hypotenuse (the slope length). This is not the usual way to specify slope; this nonstandard expression follows the sine function rather than the tangent function, so it calls

3456-463: The rate of deceleration or where the brakes have failed, several mechanisms can be used to stop a vehicle. Cars and rolling stock usually have hand brakes that, while designed to secure an already parked vehicle, can provide limited braking should the primary brakes fail. A secondary procedure called forward-slip is sometimes used to slow airplanes by flying at an angle, causing more drag. Motor vehicle and trailer categories are defined according to

3520-565: The shape of a cone or bell , some unorthodox designs have been created such as the aerospike . Some nozzles are intangible, such as the electromagnetic field nozzle of a vectored ion thruster. Continuous track is sometimes used instead of wheels to power land vehicles. Continuous track has the advantages of a larger contact area, easy repairs on small damage, and high maneuverability. Examples of vehicles using continuous tracks are tanks, snowmobiles and excavators. Two continuous tracks used together allow for steering. The largest land vehicle in

3584-736: The sine of the angle rather than the tangent) makes only an insignificant difference and can then be used as an approximation. Railway gradients are often expressed in terms of the rise in relation to the distance along the track as a practical measure. In cases where the difference between sin and tan is significant, the tangent is used. In either case, the following identity holds for all inclinations up to 90 degrees: tan ⁡ α = sin ⁡ α 1 − sin 2 ⁡ α {\displaystyle \tan {\alpha }={\frac {\sin {\alpha }}{\sqrt {1-\sin ^{2}{\alpha }}}}} . Or more simply, one can calculate

3648-462: The storing medium's energy density and power density are sufficient to meet the vehicle's needs. Human power is a simple source of energy that requires nothing more than humans. Despite the fact that humans cannot exceed 500 W (0.67 hp) for meaningful amounts of time, the land speed record for human-powered vehicles (unpaced) is 133 km/h (83 mph), as of 2009 on a recumbent bicycle . The energy source used to power vehicles

3712-440: The technology has been limited by overheating and interference issues. Aside from landing gear brakes, most large aircraft have other ways of decelerating. In aircraft, air brakes are aerodynamic surfaces that provide braking force by increasing the frontal cross section, thus increasing the increasing the aerodynamic drag of the aircraft. These are usually implemented as flaps that oppose air flow when extended and are flush with

3776-541: The use of a pulse jet was the V-1 flying bomb . Pulse jets are still occasionally used in amateur experiments. With the advent of modern technology, the pulse detonation engine has become practical and was successfully tested on a Rutan VariEze . While the pulse detonation engine is much more efficient than the pulse jet and even turbine engines, it still suffers from extreme noise and vibration levels. Ramjets also have few moving parts, but they only work at high speed, so their use

3840-695: The world according to the Guinness Book of World Records are Baldwin Street in Dunedin, New Zealand, Ffordd Pen Llech in Harlech, Wales and Canton Avenue in Pittsburgh, Pennsylvania. The Guinness World Record once again lists Baldwin Street as the steepest street in the world, with a 34.8% grade (1 in 2.87) after a successful appeal against the ruling that handed the title, briefly, to Ffordd Pen Llech . A number of streets elsewhere have steeper grades than those listed in

3904-464: The world, the Bagger 293 , is propelled by continuous tracks. Propellers (as well as screws, fans and rotors) are used to move through a fluid. Propellers have been used as toys since ancient times; however, it was Leonardo da Vinci who devised what was one of the earliest propeller driven vehicles, the "aerial-screw". In 1661, Toogood & Hays adopted the screw for use as a ship propeller. Since then,

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3968-642: The world. At least 500 million Chinese Flying Pigeon bicycles have been made, more than any other single model of vehicle. The most-produced model of motor vehicle is the Honda Super Cub motorcycle, having sold 60 million units in 2008. The most-produced car model is the Toyota Corolla , with at least 35 million made by 2010. The most common fixed-wing airplane is the Cessna 172 , with about 44,000 having been made as of 2017. The Soviet Mil Mi-8 , at 17,000,

4032-630: Was a Soviet-designed screw-propelled vehicle designed to retrieve cosmonauts from the Siberian wilderness. All or almost all of the useful energy produced by the engine is usually dissipated as friction; so minimizing frictional losses is very important in many vehicles. The main sources of friction are rolling friction and fluid drag (air drag or water drag). Wheels have low bearing friction, and pneumatic tires give low rolling friction. Steel wheels on steel tracks are lower still. Aerodynamic drag can be reduced by streamlined design features. Friction

4096-644: Was of little practical use. In 1817, The Laufmaschine ("running machine"), invented by the German Baron Karl von Drais , became the first human means of transport to make use of the two-wheeler principle . It is regarded as the forerunner of the modern bicycle (and motorcycle). In 1885, Karl Benz built (and subsequently patented) the Benz Patent-Motorwagen , the first automobile, powered by his own four-stroke cycle gasoline engine . In 1885, Otto Lilienthal began experimental gliding and achieved

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