The gravitational force, or more g-force, is a measurement of the type of acceleration that causes a perception of weight. Despite the name, it is incorrect to consider g-force a fundamental force, as "g-force" is a type of acceleration that can be measured with an accelerometer. Since g-force accelerations indirectly produce weight, any g-force can be described as a "weight per unit mass"; when the g-force acceleration is produced by the surface of one object being pushed by the surface of another object, the reaction force to this push produces an equal and opposite weight for every unit of an object's mass. The types of forces involved are transmitted through objects by interior mechanical stresses; the g-force acceleration is the cause of an object's acceleration in relation to free fall. The g-force acceleration experienced by an object is due to the vector sum of all non-gravitational and non-electromagnetic forces acting on an object's freedom to move. In practice, as noted, these are surface-contact forces between objects.
Such forces cause stresses and strains on objects, since they must be transmitted from an object surface. Because of these strains, large g-forces may be destructive. Gravitation acting alone does not produce a g-force though g-forces are expressed in multiples of the acceleration of a standard gravity. Thus, the standard gravitational acceleration at the Earth's surface produces g-force only indirectly, as a result of resistance to it by mechanical forces; these mechanical forces produce the g-force acceleration on a mass. For example, the 1 g force on an object sitting on the Earth's surface is caused by mechanical force exerted in the upward direction by the ground, keeping the object from going into free fall; the upward contact force from the ground ensures that an object at rest on the Earth's surface is accelerating relative to the free-fall condition.. Stress inside the object is ensured from the fact that the ground contact forces are transmitted only from the point of contact with the ground.
Objects allowed to free-fall in an inertial trajectory under the influence of gravitation only, feel no g-force acceleration, a condition known as zero-g. This is demonstrated by the "zero-g" conditions inside an elevator falling toward the Earth's center, or conditions inside a spacecraft in Earth orbit; these are examples of coordinate acceleration without a sensation of weight. The experience of no g-force, however it is produced, is synonymous with weightlessness. In the absence of gravitational fields, or in directions at right angles to them and coordinate accelerations are the same, any coordinate acceleration must be produced by a corresponding g-force acceleration. An example here is a rocket in free space, in which simple changes in velocity are produced by the engines and produce g-forces on the rocket and passengers.. The unit of measure of acceleration in the International System of Units is m/s2. However, to distinguish acceleration relative to free fall from simple acceleration, the unit g is used.
One g is the acceleration due to gravity at the Earth's surface and is the standard gravity, defined as 9.80665 metres per second squared, or equivalently 9.80665 newtons of force per kilogram of mass. Note that the unit definition does not vary with location—the g-force when standing on the moon is about 0.181 g. The unit g is not one of the SI units. "g" should not be confused with "G", the standard symbol for the gravitational constant. This notation is used in aviation in aerobatic or combat military aviation, to describe the increased forces that must be overcome by pilots in order to remain conscious and not G-LOC. Measurement of g-force is achieved using an accelerometer. In certain cases, g-forces may be measured using suitably calibrated scales. Specific force is another name, used for g-force; the term g-force is technically incorrect. While acceleration is a vector quantity, g-force accelerations are expressed as a scalar, with positive g-forces pointing downward, negative g-forces pointing upward.
Thus, a g-force is a vector of acceleration. It is an acceleration that must be produced by a mechanical force, cannot be produced by simple gravitation. Objects acted upon only by gravitation experience no g-force, are weightless. G-forces, when multiplied by a mass upon which they act, are associated with a certain type of mechanical force in the correct sense of the term force, this force produces compressive stress and tensile stress; such forces result in the operational sensation of weight, but the equation carries a sign change due to the definition of positive weight in the direction downward, so the direction of weight-force is opposite to the direction of g-force acceleration: Weight = mass × −g-forceThe reason for the minus sign is that the actual force on an object produced by a g-force is in the opposite direction to the sign of the g-force, since in physics, weight is not the force that produces the acceleration, but rather the equal-and-opposite reaction force to it. If the direction upward is taken as positive positive g-force produces a force/w
Van Diemen International, Ltd. was a British race car manufacturer based in Snetterton, United Kingdom. The company had a reputation for high-volume production runs of its cars, the most well-known of, its series of Formula Ford chassis, which have been at the forefront of that class of motorsport for over 20 years and led it to becoming the largest manufacturer of bespoke racing cars in the world; as well as Formula Ford, Van Diemen built cars for Formula Ford 2000, Sports 2000 and Star Mazda series. The company's purpose-built manufacturing facility was located on the grounds of Snetterton Motor Racing Circuit, allowing racing teams to test the cars right off the production line. Van Diemen was founded in 1973 by Ross Ambrose and Ralph Firman Sr. whose children Marcos Ambrose, Ralph Firman Jr. and Natasha Firman have since gone on to have successful racing careers. The company's name comes from the island of Tasmania, known as Van Diemen's Land and is where Ambrose was born and lived before moving to the UK to co-found the company.
The first car produced was the Van Diemen FA73. In 1973 Derek Lawrence won the BRDC Formula Ford 1600 championship in a FA73; the BRSCC Formula Ford was won by a FA73. This car was driven by Donald MacLeod. South African Kenny Gray won the Scottish Formula Ford Championship in 1974 in a Van Diemen RF74. Chico Serra won the BRSCC championship in 1977 driving a Van Diemen. Serra went on to win the Formula Ford Festival that season; the British car maker took over Group Racing Developments, a producer of Formula 3 chassis, at the end of 1975. A Van Diemen VG376 was entered in the British Formula 3 in 1976 and 1977; the car was a GRD 375 with updated aerodynamics. Jac Nellemann scored the best result for the car at Circuit Zolder scoring a fourth-place finish; the car manufacturer would return to Formula 3 in 1992. 1977 marked the start of a long time relationship with Duckhams Oil which sponsored the factory team until 2002. Van Diemen scored a swept the BRSCC Formula Ford 1600 championship in 1980. Brazilian drivers Roberto Moreno and Raul Boesel won 13 out of 14 races and finished one and two in the standings.
Jonathan Palmer driving Van Diemen, was third in the standings. Moreno went on to win the Formula Ford Festival followed by Tommy Byrne driving a Van Diemen. Byrne had a successful 1981 season winning the Festival and British Formula Ford 2000 championships, all driving cars made by the British car maker. Ayrton Senna made his European racing debut in 1981 in the BRSCC and RAC Formula Ford 1600 championships, driving Van Diemen chassis. After winning these two championships he graduated into Formula Ford 2000, again driving Van Diemens. In 1982 Senna won both the European Formula Ford 2000 championships; the following year fellow Brazilian Maurício Gugelmin finished second in the British Formula Ford 2000 driving a Van Diemen. In the same year Maurizio Sandro Sala won the BRDC Formula Ford 1600. In 1985 eight Van Diemens filled the top ten at the Formula Ford Festival. Jonathan Bancroft was the best placed driver finishing second; the race was won by Johnny Herbert driving a Quest-Ivey FF85. Halfway through the eighties Reynard chassis started to dominate the Formula Ford 2000.
Van Diemen shifted its focust toward Formula Renault a 2-litre engine formula. The Formula Ford Festival was won four consecutive times from 1986 thru 1989 by Van Diemen chassis. Roland Ratzenberger and Vincenzo Sospiri won the race in customer entries; the factory team won the race in 1989 with Eddie Irvine and Niko Palhares. The British constructor made its debut in the Formula Renault in 1989. Neil Riddiford won the first British Formula Renault championship in 1989. Throughout the 1990s Van Diemen began to dominate the Formula Ford market. Throughout the decade the constructor won the British Formula Ford championship five times and the Festival seven times. Jason Plato won the first Formula Renault Eurocup driving for the Duckhams Van Diemen factory team. Bobby Verdon-Roe won the British Formula Renault in 1991 in a customer entered Van Diemen; the 1991 season marked the debut of the Formula Vauxhall Junior spec racing series. Because of Van Diemens success in the Formula Ford, the marque was contracted to build all Formula Vauxhall Junior cars for the 1991 season.
This racing car used slick tires. The first championship was won by future IndyCar driver Dario Franchitti. For 1992 Van Diemen re-entered the Formula 3 market; this was the first composite chassis baring the Van Diemen name, it was built by Precision Composites. The car raced in German F3 and the French F3 championships. Franc ten Wolde raced in five races of the German F3 in a Mugen powered RF92 entered by Dutch racing team Nomag Racing. Ten Wolde finished once, in eleventh place. Nomag entered Ten Wolde in the 1992 Masters of Formula 3; the Honda powered cars entered in the Japanese F3 and French F3 had little success entering only a few races. After this disappointing season Van Diemen did not return to Formula 3. With the demise of Formula Ford 2000, Van Diemen began to export its cars to the United States. 1992 was a successful year for Van Diemen in the American F2000 series. Greg Ray won the SCCA F2000 championship. Back in Europe James Matthews, driving for Manor Motorsport, won the 1994 Formula Renault Eurocup in a Van Diemen.
Van Diemen cars won the first two official USF2000 championships in 1995 and 1996 with Jeret Schroeder and Steve Knapp. Van Diemen dominated the series winning all drivers and constructors titles until the series folded after the 2006 season. Many aspiring drivers won races with the British brand like Buddy Rice and Dan Whel
Andrew Graham "Andy" Priaulx, MBE is a British professional racing driver from Guernsey racing for Ford Chip Ganassi Team UK in the FIA World Endurance Championship, having been a former BMW factory driver. He is a European Touring Car Championship champion, three times World Touring Car Championship champion and the only FIA Touring Car champion to win an international-level championship for four consecutive years; the previous record was Roberto Ravaglia's three successive championships. Born in Guernsey, Priaulx has competed in many types of motorsport, beginning in karting at the minimum age of eight. After a brief flirtation with powerboat racing, he started hillclimbing while still a teenager, sharing a car with his father Graham, it was apparent that he had great natural ability, few people were surprised when he took the British Hillclimb Championship title in 1995. After this, he made the switch to circuit racing, where after a low-key couple of years in Formula Renault UK Championship and British Formula 3 he demonstrated his skills were transferable by switching to the Renault Spider championship in 1998 dominating it in 1999.
His career stalled somewhat when he returned to British Formula 3 in 2000–01. He had some success at this level, but despite finishing sixth in the championship in 2001 was unable to progress further up the single-seater ladder. In 2001 Priaulx had a pair of British Touring Car Championship guest drives for the Egg Vauxhall team, standing in for the suspended Phil Bennett, he stunned the regulars by taking pole position on his debut at Oulton Park, demonstrating that his future appeared to lie in that direction. The following year he was signed by the works Honda BTCC team for their 2002 campaign, he won one race and finished on the podium in two others, the following season was signed by Bart Mampaey's BMW UK team for their European Touring Car Championship effort. He was in contention for the title until late in the year finishing third. Priaulx occasionally guested in Australian V8 Supercar racing, competing at the Bathurst 1000km in 2002 with Yvan Muller in a Kmart Racing Commodore and 2003 with Cameron McLean again in a Kmart Commodore, the Sandown 500 km in 2003.
2004 saw Priaulx win a major circuit racing championship, as he became ETCC champion after a season-long battle with Dirk Müller. Both men obtained the same number of points, but Priaulx had won five races as against Müller's three, this was sufficient to hand the Priaulx the title. Priaulx repeated his 2004 success in 2005, 2006 and 2007, clinching the World Touring Car Championship at the final round in Macau. In 2005, he won the crown with two second-place finishes in the final round when his nearest rivals, Dirk Müller and Fabrizio Giovanardi both failed to score; the following year, a win in the opening race of the final meeting left him needing to finish fifth in the final event to beat Jörg Müller by a single point, which he achieved. Heading into the final meeting of the 2007 WTCC season at Macau, Priaulx was joint leader of the championship alongside former BTCC champion Yvan Muller, he came eighth in the first race and won from pole position in the second race to claim his and BMW's third WTCC championship in a row.
He was appointed Member of the Order of the British Empire in the 2008 Birthday Honours. Priaulx again raced in the World Touring Car Championship for BMW Team UK in 2009, finishing fourth in the standings; as well as the WTCC, he competed in selected rounds of the American Le Mans Series for BMW and a number of races in the Australian V8 Supercars championship, driving a Walkinshaw Racing Holden with David Reynolds at the Phillip Island and Bathurst endurance races. In 2010, Priaulx continued to race in the World Touring Car Championship for BMW and competed in several races for BMW in the Le Mans Series, 2010 Armor All Gold Coast 600 in V8 Supercars with Craig Lowndes, Race of Champions, as well as the Le Mans 24 Hours. On 5 December 2010, BMW announced that it would not be continuing its factory effort in the World Touring Car Championship from 2011 onwards, it was announced on 25 January 2011, that Priaulx contest the Intercontinental Le Mans Cup for BMW, as well as undertaking testing duties for BMW with cars from other racing categories.
Priaulx spent the 2012 and 2013 seasons racing for BMW in the Deutsche Tourenwagen Masters, scoring his best result in the final round of the 2013 season at the Hockenheimring, where he finished in sixth after starting in third. He switched to racing in the United SportsCar Championship in the United States for 2014. In January 2015 it was announced at Autosport International that Priaulx would return to the British Touring Car Championship for 2015 with West Surrey Racing, campaigning a BMW 125i M Sport, combining his BTCC programme with racing works BMWs in the European Le Mans Series and the North American Endurance Cup. On 10 December 2018, it was announced that Priaulx will join Lynk & Co Cyan Racing for the 2019 World Touring Car Cup season, partnering former WTCC champions Yvan Muller, Thed Björk and Yvan's nephew Yann Ehrlacher. On 5 December 2015, it was announced that Priaulx had parted ways with BMW after a 13-year stint with the German manufacturer to join Ford Chip Ganassi Team UK for their upcoming debut in the 2016 FIA World Endurance Championship season.
He was unveiled as a Ford driver on 5 January 2016 alongside teammates Marino Franchitti, Stefan Mücke, Olivier Pla. Priaulx's son Sebastian Priaulx is a racing driver. Although Priaulx is British, he has been mistakenly identified as French, due to his surname (pronounced pree-oh /pr
A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface traveled over. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, which provide a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, designed to match the weight of the vehicle with the bearing strength of the surface that it rolls over by providing a bearing pressure that will not deform the surface excessively; the materials of modern pneumatic tires are synthetic rubber, natural rubber and wire, along with carbon black and other chemical compounds. They consist of a body; the tread provides traction. Before rubber was developed, the first versions of tires were bands of metal fitted around wooden wheels to prevent wear and tear. Early rubber tires were solid. Pneumatic tires are used on many types of vehicles, including cars, motorcycles, trucks, heavy equipment, aircraft.
Metal tires are still used on locomotives and railcars, solid rubber tires are still used in various non-automotive applications, such as some casters, carts and wheelbarrows. The word tire is a short form of attire, from the idea; the spelling tyre does not appear until the 1840s when the English began shrink fitting railway car wheels with malleable iron. Traditional publishers continued using tire; the Times newspaper in Britain was still using tire as late as 1905. The spelling tyre began to be used in the 19th century for pneumatic tires in the UK; the 1911 edition of the Encyclopædia Britannica states that "he spelling'tyre' is not now accepted by the best English authorities, is unrecognized in the US", while Fowler's Modern English Usage of 1926 says that "there is nothing to be said for'tyre', etymologically wrong, as well as needlessly divergent from our own older & the present American usage". However, over the course of the 20th century, tyre became established as the standard British spelling.
The earliest tires were bands of leather iron placed on wooden wheels used on carts and wagons. The tire would be heated in a forge fire, placed over the wheel and quenched, causing the metal to contract and fit on the wheel. A skilled worker, known as a wheelwright, carried out this work; the first patent for what appears to be a standard pneumatic tire appeared in 1847 lodged by the Scottish inventor Robert William Thomson. However, this never went into production; the first practical pneumatic tire was made in 1888 on May Street, Belfast, by Scots-born John Boyd Dunlop, owner of one of Ireland's most prosperous veterinary practices. It was an effort to prevent the headaches of his 10-year-old son Johnnie, while riding his tricycle on rough pavements, his doctor, John Sir John Fagan, had prescribed cycling as an exercise for the boy, was a regular visitor. Fagan participated in designing the first pneumatic tires. Cyclist Willie Hume demonstrated the supremacy of Dunlop's tires in 1889, winning the tire's first-ever races in Ireland and England.
In Dunlop's tire patent specification dated 31 October 1888, his interest is only in its use in cycles and light vehicles. In September 1890, he was made aware of an earlier development but the company kept the information to itself. In 1892, Dunlop's patent was declared invalid because of prior art by forgotten fellow Scot Robert William Thomson of London, although Dunlop is credited with "realizing rubber could withstand the wear and tear of being a tire while retaining its resilience". John Boyd Dunlop and Harvey du Cros together worked through the ensuing considerable difficulties, they employed inventor Charles Kingston Welch and acquired other rights and patents which allowed them some limited protection of their Pneumatic Tyre business's position. Pneumatic Tyre would become Dunlop Tyres; the development of this technology hinged on myriad engineering advances, including the vulcanization of natural rubber using sulfur, as well as by the development of the "clincher" rim for holding the tire in place laterally on the wheel rim.
Synthetic rubbers were invented in the laboratories of Bayer in the 1920s. In 1946, Michelin developed the radial tire method of construction. Michelin had bought the bankrupt Citroën automobile company in 1934, so it was able to fit this new technology immediately; because of its superiority in handling and fuel economy, use of this technology spread throughout Europe and Asia. In the U. S. the outdated bias-ply tire construction persisted, with market share of 87% as late as 1967. Delay was caused by tire and automobile manufacturers in America "concerned about transition costs." In 1968, Consumer Reports, an influential American magazine, acknowledged the superiority of radial construction, setting off a rapid decline in Michelin's competitor technology. In the U. S. the radial tire now has a market share of 100% in automobiles. Today, over 1 billion tires are produced annually in over 400 tire factories. There are 2 aspects to. First, tension in the cords pull on the bead uniformly around the wheel, except where it is reduced above the contact patch.
Second, the bead transfers that net force to the rim. Air pressure, via the ply cords, exerts tensile force on the entire bead surrounding th
A value-added tax, known in some countries as a goods and services tax, is a type of tax, assessed incrementally, based on the increase in value of a product or service at each stage of production or distribution. VAT compensates for the shared services and infrastructure provided in a certain locality by a state and funded by its taxpayers that were used in the elaboration of that product or service. Not all localities require VAT to be charged and goods and services for export may be exempted. VAT is implemented as a destination-based tax, where the tax rate is based on the location of the consumer and applied to the sales price. Confusingly, the terms VAT, GST, consumption tax and sales tax are sometimes used interchangeably. VAT raises about a fifth of total tax revenues both worldwide and among the members of the Organisation for Economic Co-operation and Development; as of 2018, 166 of the 193 countries with full UN membership employ a VAT, including all OECD members except the United States, which uses a sales tax system instead.
There are two main methods of calculating VAT: the credit-invoice or invoice-based method, the subtraction or accounts-based method. Using the credit-invoice method, sales transactions are taxed, with the customer informed of the VAT on the transaction, businesses may receive a credit for VAT paid on input materials and services; the credit-invoice method is the most employed method, used by all national VATs except for Japan. Using the subtraction method, at the end of a reporting period, a business calculates the value of all taxable sales subtracts the sum of all taxable purchases and the VAT rate is applied to the difference; the subtraction method VAT is only used by Japan, although subtraction method VATs using the name "flat tax", have been part of many recent tax reform proposals by US politicians. With both methods, there are exceptions in the calculation method for certain goods and transactions, created for either pragmatic collection reasons or to counter tax fraud and evasion. Germany and France were the first countries to implement VAT, doing so in the form of a general consumption tax during World War I.
The modern variation of VAT was first implemented by France in 1954 in Ivory Coast colony. Recognizing the experiment as successful, the French introduced it in 1958. Maurice Lauré, Joint Director of the France Tax Authority, the Direction Générale des Impôts implemented the VAT on 10 April 1954, although German industrialist Dr. Wilhelm von Siemens proposed the concept in 1918. Directed at large businesses, it was extended over time to include all business sectors. In France, it is the most important source of state finance, accounting for nearly 50% of state revenues. A 2017 study found that the adoption of VAT is linked to countries with corporatist institutions; the amount of VAT is decided by the state as percentage of the end-market price. As its name suggests, value-added tax is designed to tax only the value added by a business on top of the services and goods it can purchase from the market. To understand what this means, consider a production process where products get successively more valuable at each stage of the process.
When an end-consumer makes a purchase, they are not only paying for the VAT for the product at hand, but in effect, the VAT for the entire production process, since VAT is always included in the prices. The value-added effect is achieved by prohibiting end-consumers from recovering VAT on purchases, but permitting businesses to do so; the VAT collected by the state is computed as the difference between the VAT of sales earnings and the VAT of those goods and services upon which the product depends. The difference is the tax due to the value added by the business. In this way, the total tax levied at each stage in the economic chain of supply is a constant fraction; the standard way to implement a value-added tax involves assuming a business owes some fraction on the price of the product minus all taxes paid on the good. By the method of collection, VAT can be invoice-based. Under the invoice method of collection, each seller charges VAT rate on his output and passes the buyer a special invoice that indicates the amount of tax charged.
Buyers who are subject to VAT on their own sales consider the tax on the purchase invoices as input tax and can deduct the sum from their own VAT liability. The difference between output tax and input tax is paid to the government. Under the accounts based method, no such specific invoices are used. Instead, the tax is calculated on the value added, measured as a difference between revenues and allowable purchases. Most countries today use the invoice method, the only exception being Japan, which uses the accounts method. By the timing of collection, VAT can be either cash based. Cash basis accounting is a simple form of accounting; when a payment is received for the sale of goods or services, a deposit is made, the revenue is recorded as of the date of the receipt of funds—no matter when the sale had been made. Cheques are written when funds are available to pay bills, the expense is recorded as of the cheque date—regardless of when the expense had been incurred; the primary focus is on the amount of cash in the bank, the secondary focus is on making sure all bills are paid.
Little effort is made to match revenues to the time period in which they are earned, or to match expenses to the time period in which they are incurr
A limited-slip differential is a type of differential that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. In an automobile, such limited-slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity. In 1932, Ferdinand Porsche designed a Grand Prix racing car for the Auto Union company; the high power of the design caused one of the rear wheels to experience excessive wheel spin at any speed up to 160 km/h. In 1935, Porsche commissioned the engineering firm ZF to design a limited-slip differential to improve performance; the ZF "sliding pins and cams" became available, one example was the Type B-70 used during the Second World War in the military VWs, although technically this was not a limited-slip differential, but a system composed of two freewheels, which sent the whole of the engine power to the slower-turning of the two wheels.
The main advantage of a limited-slip differential is demonstrated by considering the case of a standard differential in off-roading or snow situations where one wheel begins to slip. In such a case with a standard differential, the slipping or non-contacting wheel will receive the majority of the power, while the contacting wheel will remain stationary with respect to the ground; the torque transmitted by an open differential will always be equal at both wheels. For example, the right tire might begin to spin as soon as 70 N⋅m of torque is placed on it, since it is on an icy surface. Since the same amount of torque is always felt at both wheels, regardless of the speed at which they are turning, this means that the wheel with traction cannot receive more than 70 Nm of torque either, far less than is required to move the vehicle. Meanwhile, the tire on the slippery surface will spin, absorbing all of the actual power output though both wheels are provided the same amount of torque. In this situation, a limited-slip differential prevents excessive power from being allocated to one wheel, so keeps both wheels in powered rotation, ensuring that the traction will not be limited to the wheel which can handle the minimum amount of power.
The advantages of LSD in high-power, rear wheel drive automobiles were demonstrated during the United States "Muscle-Car" era from the mid 1960s through the early 1970s. Cars of this era were rear wheel drive and did not feature independent suspension for the rear tires. With a live axle, when high torque is applied through the differential, the traction on the right rear tire is lower as the axle wants to turn with the torsion of the drive shaft; this coined the terms "one wheel peel" or "one tire fire". As such, "Muscle-Cars" with LSD or "posi" were at a distinct advantage to their wheel-spinning counterparts. Automotive limited-slip differentials all contain a few basic elements. First, all have a gear train that, like an open differential, allows the output shafts to spin at different speeds while holding the sum of their speeds proportional to that of the input shaft. Second, all have some type of mechanism that applies a torque that resists the relative motion of the output shafts. In simple terms, this means they have some mechanism which resists a speed difference between the outputs, by creating a resisting torque between either the two outputs, or the outputs and the differential housing.
There are many mechanisms used to create this resisting torque. Types of limited-slip differential are named from the type of the resisting mechanism. Examples include clutch-based LSDs; the amount of limiting torque provided by these mechanisms varies by design. A limited-slip differential has a more complex torque-split and should be considered in the case when the outputs are spinning the same speed and when spinning at different speeds; the torque difference between the two axles is called Trq d.. Trq d is the difference in torque delivered to the left and right wheel; the magnitude of Trq d comes from the slip-limiting mechanism in the differential and may be a function of input torque, or the difference in the output speeds. The torque delivered to the outputs is: Trq 1 = ½ Trq in + ½ Trq d for the slower output Trq 2 = ½ Trq in – ½ Trq d for the faster outputWhen traveling in a straight line, where one wheel starts to slip, torque is reduced to the slipping wheel and provided to the slower wheel.
In the case when the vehicle is turning and neither wheel is slipping, the inside wheel will be turning slower than the outside wheel. In this case the inside wheel will receive more torque than the outside wheel, which can result in understeer; when both wheels are spinning at the same speed, the torque distribution to each wheel is: Trq = ½ Trq in ± while Trq 1 +Trq 2 =Trq in. This means the maximum torque to either wheel is statically indeterminate but is in the range of ½ Trq in ±. Several types of LSD are used in passenger cars. Fixed value Torque sensitive Speed sensitive Electronically controlled In this differential the maximum torque difference between the two outputs, Trq d, is a fixed value at all times regard
Hewland is a British engineering company, founded in 1957 by Mike Hewland, which specialises in racing-car gearboxes. Hewland employ 130 people at their Maidenhead facility and have diversified into a variety of markets being successful in electric vehicle transmission supply. Hewland are supplying into Formula 1, Formula E, DTM, LMP, RallyCross, Prototype and GT Sportscar. Mike Hewland ran a small engineering business at Maidenhead in the UK with the speciality in gear cutting. In 1959, Bob Gibson-Jarvie, the Chief Mechanic of UDT Laystall racing team running Cooper F2 cars, sought help from Hewland as gearbox troubles were experienced; the result of this request came out as six successful gearboxes being designed and built in 1959, Hewland was in the gearbox business. The first transaxle product, the Hewland Mk. I of 1960, was a minor modification of the Volkswagen Beetle 4 speed transaxle used upside-down with custom made differential housing side plates for the midship engine Lola Mk. III built for the new Formula Junior rules in 1961.
Hewland Mk. II was a similar 4 speed transaxle with more modifications for Coventry Climax engined Elva Mk. VI 1.1 litre sports racer in 1961. Hewland Mk. III of 1962 became the first product for the public, which used the magnesium alloy case of the Beetle transaxle to house 5 pairs of bespoke straight-cut constant mesh spur gears with dog rings operated by custom-made brass shift forks. Gear selector shaft was located in the nose housing, unmodified as in the Beetle set up, facing rear-ward at the tail end of the box in the front-side-back position on a midship engine racing cars; the elimination of synchromesh parts provided the space for an additional pair of gears for the 5th speed. This Mk. III became popular for small displacement formula cars and racing sports cars, was the basis on which all the products were built. Mk. IV had the tail casing made by Hewland, with the selector rod located in the right side lower position, facing forward; this made the shifter linkage design easier on the part of chassis manufacturers.
Together with its high torque version Mk. V, Mk. IV became a big seller. Mk. VI of 1965 was an improved version of Mk. IV, which established Hewland as the dominant volume production transaxle manufacturer in the small displacement midship-engine racing car market, helped by the de facto standard usage in the newly born Formula Ford series. Although Formula Ford engines displaced 1.6-litre, the capacity was not a problem as the 1.5-litre rating was for higher power racing engines as opposed to the single carburetor, production cam and compression ratio regulation of the formula. The advantages of the series were: Dog-ring gear selection made it quick shifting; the structure that enabled changing of gear ratios on the 2nd through 5th speeds possible without removing the transaxle from the vehicle, or detaching it from the engine. Upside-down usage enabled the dry sump racing engines to be mounted low on the chassis; the 3rd, 4th and the 5th gears had the same thickness and drive/driven axis distance, thus were interchangeable.
Magnesium alloy Volkswagen case made it strong and light weight. Hewland was claimed to be the first company that made racing car gearboxes, however, a transaxle housed in an aluminium alloy case for racing purpose in midship-engine configuration had been designed by Ferdinand Porsche and built by Horch in 1933 as a part of Auto Union Type A. Valerio Colotti had been producing gearboxes for racing purposes before 1959, his transaxle for midship-engine racing cars debuted on 10 May 1959 at Monaco Grand Prix on Behra-Porsche. Colotti 5 speed T.32 transaxle, which weighed less than 35 kg, was in use by Rob Walker in 1960. Lotus Engineering made a transaxle for front-engine Lotus 12 in 1957 designed by Richard Ansdale and Harry Mundy, this gearbox/differential unit was adopted to midship-engine use for Lotus 18 which debuted on 8 April 1960. Hewland dominated the racing scenes in the 1960s, 70s, 80s and 90s, still is a leading company in racing transmissions with its focus shifted a bit toward custom engineering work for vehicle manufacturers.
In addition to the traditional manual transmission products covering all the racing and rallying classes, Hewland now offers a complete semi-automatic transmission components including shift actuators, throttle actuators, shift position sensors and steering wheel paddle systems. The following is the list of the smaller product range housed in Volkswagen case except for LD200. Transmission capacity is measured by the maximum output torque, the product of the input torque times overall reduction ratio. However, as the output torque is proportional to the input torque with typical gear and differential reduction ratios, as the input torque is proportional to the engine displacement, Hewland used to indicate the maximum allowable engine size, the maximum input torque measured in Lbs/ft. as the transaxle selection guide. The following is the list of larger product range up to 1981. After an approach from Richard Noble, Hewland was persuaded to design and build the AE75, a 75 bhp aero-engine for Noble ARV Super2, a 2-seater light aircraft.
This engine, an inverted three-cylinder water-cooled two-stroke unit with dual ignition and a 2.7:1 reduction gearbox, was developed from Hewland's existing two-cylinder microlight engine. The AE75 was light at 49 kg, thereby contributing to the overall lightness of the aircraft, so that the ARV Super2 weighed 40% less than its competitor, the Cessna 152. Hewland has been involved with various track day cars. Most