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In automotive design, an RMR, or rear mid-engine, rear-wheel-drive layout (now simply known as MR, or mid-engine, rear-wheel-drive layout), is one in which the rear wheels are driven by an engine placed just in front of them (i.e., the rear axle), behind the passenger compartment. In contrast to the rear-engined RR layout, the center of mass of the engine is in front of the rear axle. This layout is typically chosen for its low moment of inertia and relatively favorable weight distribution (the heaviest component is within the wheelbase, making the main component of its moment of inertia relatively low). The layout has a tendency toward being heavier in the rear than the front, which allows for best balance to be achieved under braking. However, since there is little weight over the front wheels, under acceleration, the front of the car is prone to lift and cause understeer. Most rear-engine layouts have historically been used in smaller vehicles, because the weight of the engine at the rear has an adverse effect on a larger car's handling, making it 'tail-heavy'.It is felt that the low polar inertia is crucial in selection of this layout. The mid-engined layout also uses up central space, making it impractical for any but two-seater sports cars. However, some microvans use this layout, with a small, low engine beneath the loading area. This makes it possible to move the driver right to the front of the vehicle, thus increasing the loading area at the expense of slightly reduced load depth.
In modern racing cars, RMR is the usual configuration and is usually synonymous with "mid-engine". Due to its weight distribution and resulting in favorable vehicle dynamics, this layout is heavily employed in open-wheel Formula racing cars (such as Formula One and IndyCar) as well as purpose-built sports racing cars. This configuration was also common in very small engined 1950s microcars, in which the engines did not take up much space. Because of successes in racing, the RMR platform has been popular for road-going sports cars despite the inherent challenges of design, maintenance and lack of cargo space. The similar mid-engine, four-wheel-drive layout gives many of the same advantages and is used when extra traction is desired, such as in some supercars and in the Group B rally cars.
The 1900 NW Rennzweier was one of the first race cars with mid-engine, rear-wheel-drive layout. Other known historical examples include the 1923 Benz Tropfenwagen. It was based on an earlier design named the Rumpler Tropfenwagen in 1921 made by Edmund von Rumpler, an Austrian engineer working at Daimler. The Benz Tropfenwagen was designed by Ferdinand Porsche along with Willy Walb and Hans Nibel. It raced in 1923 and 1924 and was most successful in the Italian Grand Prix in Monza where it stood fourth. Later, Ferdinand Porsche used mid-engine design concept towards the Auto Union Grand Prix cars of the 1930s which became the first winning RMR racers. They were decades before their time, although MR Miller Specials raced a few times at Indianapolis between 1939 and 1947. In 1953 Porsche premiered the tiny and altogether new RMR 550 Spyder and in a year it was notoriously winning in the smaller sports and endurance race car classes against much larger cars – a sign of greater things to come. The 718 followed similarly in 1958. But it was not until the late 1950s that RMR reappeared in Grand Prix (today's "Formula One") races in the form of the Cooper-Climax (1957), soon followed by cars from BRM and Lotus. Ferrari and Porsche soon made Grand Prix RMR attempts with less initial success. The mid-engined layout was brought back to Indianapolis in 1961 by the Cooper Car Company with Jack Brabham running as high as third and finishing ninth. Cooper did not return, but from 1963 on British built mid-engined cars from constructors like Brabham, Lotus and Lola competed regularly and in 1965 Lotus won Indy with their Type 38.
Rear mid-engines were widely used in microcars like the Isetta or the Zündapp Janus.
The first rear mid-engined road car after WW II was the 1962 (Rene) Bonnet / Matra Djet, which used the 1108cc Renault Sierra engine, mated to the transaxle from the FWD Renault Estafette van. Nearly 1700 were built until 1967. This was followed by the first De Tomaso, the Vallelunga, which mated a tuned Ford Cortina 1500 Kent engine to a VW transaxle with Hewland gearsets. Introduced at Turin in 1963, 58 were built 1964–68. A similar car was the Renault-engined Lotus Europa, built from 1966 to 1975.
Finally, in 1966, the Lamborghini Miura was the first high performance mid-engine, rear-wheel-drive road car. The concept behind the Miura was that of putting on the road a grand tourer featuring state-of-the-art racing-car technology of the time; hence the Miura was powered by a V12 transversely mounted between the rear wheels, solidal to the gearbox and differential.This represented an extremely innovative sportscar at a time when all of its competitors (aside from the rear-engined Porsches), from Ferraris to Aston Martins, were traditional front-engined, rear-wheel-drive grand tourers.
The Pontiac Fiero was a mid-engined sports car that was built by the Pontiac division of General Motors from 1984 to 1988. The Fiero was the first two-seater Pontiac since the 1926 to 1938 coupes, and also the first mass-produced mid-engine sports car by a U.S. manufacturer.
A V6 engine is a six-cylinder piston engine where the cylinders share a common crankshaft and are arranged in a V configuration.
A sports car is a car designed with an emphasis on dynamic performance, such as handling, acceleration, top speed, or thrill of driving. Sports cars originated in Europe in the early 1900s and are currently produced by many manufacturers around the world.
The Lamborghini Countach is a rear mid-engine, rear-wheel-drive sports car produced by the Italian automobile manufacturer Lamborghini from 1974 to 1990. It is one of the many exotic designs developed by Italian design house Bertone, which pioneered and popularized the sharply angled "Italian Wedge" shape.
The Lamborghini Miura is a sports car produced by Italian automaker Lamborghini between 1966 and 1973. The car was the first supercar with a rear mid-engined two-seat layout, although the concept was first seen in a production road car with René Bonnet's Matra Djet, introduced in 1964. This layout has since become the standard for high-performance sports and supercars. When released, it was the fastest production road car.
A hot hatch is a high-performance hatchback car.
Front-wheel drive (FWD) is a form of engine and transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel-drive and four-wheel drive vehicles.
The Horizon is a compact hatchback that was designed by Chrysler Europe and was produced from 1978 to 1987 under the Chrysler, Simca, and Talbot nameplates. The successor of both the Simca 1100 and Hillman Avenger, the Horizon adopted a front-wheel drive, transverse-engine layout.
In automotive design, an FF, or front-engine, front-wheel-drive (FWD) layout places both the internal combustion engine and driven roadwheels at the front of the vehicle.
In automotive design, an RR, or rear-engine, rear-wheel-drive layout places both the engine and drive wheels at the rear of the vehicle. In contrast to the RMR layout, the center of mass of the engine is between the rear axle and the rear bumper. Although very common in transit buses and coaches due to the elimination of the drive shaft with low-floor buses, this layout has become increasingly rare in passenger cars.
A transaxle is a single mechanical device which combines the functions of an automobile's transmission, axle, and differential into one integrated assembly. It can be produced in both manual and automatic versions.
A mid-engine layout describes the placement of an automobile engine in front of the rear-wheel axles, but behind the front axle.
Jouef was a French manufacturer that specialized in model trains and other vehicles. Its name continues as a brand owned by Hornby Railways.
The Simca 1100 is a car built from 1967 to 1982 by Simca. It was replaced by the Simca-Talbot Horizon.
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the direction of travel. Many modern front-wheel drive vehicles use this engine mounting configuration. Most rear-wheel drive vehicles use a longitudinal engine configuration, where the engine's crankshaft axis is parallel with the direction of travel, except for some rear-mid engine vehicles, which use a transverse engine and transaxle mounted in the rear instead of the front. Despite typically being used in light vehicles, it is not restricted to such designs and has also been used on armoured fighting vehicles to save interior space.
The Matra Murena is a mid-engined, rear wheel drive sports car that was produced from 1980 through 1983 by the French engineering group Matra. The factory was located in the commune of Romorantin-Lanthenay in the department of Loir-et-Cher in central France.
In automotive design, a Front Mid-engine, Front-wheel-drive layout is one in which the front road wheels are driven by an internal-combustion engine placed just behind them, in front of the passenger compartment. In contrast to the Front-engine, front-wheel-drive layout (FF), the center of mass of the engine is behind the front axle. This layout is typically chosen for its better weight distribution. Since the differences between the FF and MF layouts are minor, most people consider the MF layout to be the same as the FF layout.
The Matra Bagheera is a sports car built by the automotive division of the French engineering group Matra in cooperation with automaker Simca. It was marketed as the Matra-Simca Bagheera until its final year of production, when its designation was changed to the Talbot-Matra Bagheera following Chrysler Europe's demise and subsequent takeover by PSA.
The Matra Rancho is a leisure activity vehicle created by the French engineering group Matra, in cooperation with the automaker Simca, to capitalize on the off-road trend started by the Range Rover. The Rancho provided an "off-road look" at a lower price.
In automobile design, a rear-engine design layout places the engine at the rear of the vehicle. The center of gravity of the engine itself is behind the rear axle. This is not to be confused with the center of gravity of the whole vehicle, as an imbalance of such proportions would make it impossible to keep the front wheels on the ground.
The Matra 530 is a sports car created and built by the French engineering group Matra.