Rear mid-engine, rear-wheel-drive layout

In automotive design, a 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, 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 near the center of the car, 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'.[1] 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 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.

Automotive diagrams 04 En
RMR layout; the engine is located in front of the rear axle.
Automotive diagrams 12 En
Rear Mid-engine transversely-mounted / Rear-wheel drive

History

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 1966–1975.

Finally, in 1966, the Lamborghini Miura was the first high performance mid-engine, rear-wheel-drive roadcar. 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.[2] 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 and only mass-produced mid-engine sports car by a U.S. manufacturer.

Gallery

Rear mid-engine transversely-mounted, rear-wheel-drive layout

NW Rennzweier Side

NW Rennzweier, first of the long line of Tatra racing cars.

1971 Lamborghini Miura SV 385hp V12, 4L p5

The Lamborghini Miura, incorrectly accounted as the first mid-engined roadcar.

Lancia Stratos HF 001

The Lancia Stratos HF was powered by a mid-transverse mounted Dino Ferrari V6, and proved to be very successful as a rally car.

1978 Fiat X1.9 in white, front left

The Fiat X1/9 was designed around the all-new front wheel drive Fiat 128, but used these parts in a radical way, moving the entire transverse drive train and suspension assembly from the front of the 128 to the rear of the passenger cabin.

1974 MATRA SIMCA BAGHEERA, pic10

As with most "rear mid-engine transversely-mounted / rear-wheel-drive layouts", the Matra-Simca Bagheera shared Simcas 1100 and 1307 front-wheel-drive mechanicals, but placed behind the passenger compartment.[3]

MR2 Blue HP

Toyota MR2 Spyder is the third generation MR2.

Lotus Evora - Flickr - Alexandre Prévot (3) (cropped)

In the Lotus Evora, platform and mechanicals are uniquely designed for the vehicle.

1990 Consulier GTP-LX, John Fitch's car (fR)

The Consulier GTP incorporated a mid-transverse mounted Chrysler 2.2 Turbo III engine; it was successful in IMSA competition until it was banned in 1991.

Rear mid-engine longitudinally-mounted, rear-wheel-drive layout

Porsche 550

The Porsche 550 Spyder produced from 1953–1956.

Rene Bonnet 1962-1965

The René Bonnet Djet, the first production mid-engined road sports car.

Renault 5 Maxiturbo Jarama 2006e

Renault 5 Turbo by predecessor Renault 5.

VW-Porsche 914 am 17.06.2007

Porsche 914 shared VW mechanicals and was sold in Europe as the VW-Porsche 914.

2013 Porsche Boxster -- 2012 NYIAS

The Porsche Boxster could be considered a successor to the 914.

1996 McLaren F1

McLaren F1{snd}} during its production run, the fastest production car available.

1974 Ferrari 365 GT4 Boxer Berlinetta front

The 1973 365 GT4 BB, Ferrari's first mid-engined GT car.

Red Ferrari Mondial Cabrio

The Ferrari Mondial, world's only production 4 seat mid-engined convertible.

References

  1. ^ Hillier, Victor; Peter Coombes (2004). Fundamentals of motor vehicle technology. Nelson Thornes. p. 9. ISBN 978-0-7487-8082-2.
  2. ^ "History". Official Lamborghini website. Archived from the original on 2012-12-20. Retrieved 2012-12-04.
  3. ^ "Matra-Simca Bagheera". Simca Talbot Information Centre – Simca Club UK. Retrieved 2006-08-19.

External links

Clio V6 Renault Sport

The Renault Clio V6 Renault Sport is a rear mid-engine, rear-wheel-drive layout hot hatch based on the Renault Clio launched in 2001. Designed by French automaker Renault the Phase 1 models were built by Tom Walkinshaw Racing (TWR) in Uddevalla, Sweden and Phase 2 were designed and hand built by Renault Sport in Dieppe, France. Both variants were developed by TWR. The mid-engined, wide-body concept of the Clio V6 was very reminiscent of the 1980s Renault 5 Turbo. Both road going models were low volume production making them very rare cars. Alongside the road car, a circuit only version was produced, known as the Clio V6 Trophy. This was a full competition car, with sequential Sadev gearbox, full roll cage, magnesium wheels and engine output upped to 285 PS (210 kW; 281 bhp).

GTM Libra

The Libra was launched by GTM Cars Ltd on the UK kitcar market in 1998. Three years in development it was a collaboration between GTM Cars directors Peter Beck & Paddy Fitch, designer Richard Oakes and suspension designer Bryn Davies.

Conceived as a lightweight sportscar, it uses no subframes for its suspension with all the mountings being bolted straight to the GRP monocoque tub.

At the front it uses unequal length wishbones of GTM design locating uprights from the Rover Metro/100 range and a forward mounted steering rack for extra legroom. The rear suspension is an unusual double trailing arm design, bolted to the rear bulkhead and using the same uprights as the front.

The engine/transmission unit is held in a frame hanging off the rear bulkhead, a frame which also locates the rear hinging engine cover which incorporates a sizeable boot which can accommodate a full size set of golf clubs.

The front 'clamshell' conceals the radiator, battery, master cylinders etc. and also manages to stow a full size spare wheel (either 16" or 17"). A removable roof panel can be stowed behind the seats for an open top experience.

Initially launched with the 1.4 litre Rover 'K'-Series engine, the Libra has been fitted successfully with 1.6, 1.8, 1.8 VVC and KV6 2.5 litre Rover engines as well as some Honda units and the Audi 1.8 turbo engine.

Ginetta G32

The Ginetta G32 is a mid-engined sports car built by British car manufacturer Ginetta Cars from 1989 to 1992.

HPI Baja 5B/5T

The HPI Baja 5B and Baja 5T is a 1:5 scale radio controlled off-road buggy and truck manufactured by Hobby Products International (HPI). The car is sold either in a kit or RTR (Ready to Run), in a 23cc gasoline engine or for a short period, battery powered. Initially introduced with a buggy body style, a short course truck style was later offered to the market and was joined in 2015 by the Baja 5R, an on-road car.

Hofstetter Turbo

The Hofstetter Turbo is a Brazilian car created in the 1980s by Mario Richard Hofstetter. In 1980 Hofstetter pulled out his drawing paper and started to draw a prototype of the car. Mario Hofstetter made this car at this time because the Brazilian government was very strict and didn't allow many imports into Brazil. In 1982 he started to put the mid-engined car together with some other workers, and began the Hofstetter company in 1984. Mario Hofstetter only was able to sell 18 cars throughout (1986–1991).

Holden Hurricane

The Holden Hurricane is a two-seat concept car built by Holden in 1969. The Hurricane was one of the most advanced vehicles for its time, with Holden describing it as a research vehicle, allowing them "to study design trends, propulsion systems and other long range developments".

Leblanc (automobile manufacturer)

Leblanc is a Zürich based Swiss car manufacturer. It makes modified high-performance automobiles in very low quantities. The company is just beginning to enter the American market.

MR

MR, Mr, mr, or mR may refer to:

Mr., an honorific title of men

NW B

The NW type B is a veteran automobile manufactured by Nesselsdorfer Wagenbau-Fabriks-Gesellschaft A.G. (NW, now known as Tatra). Initially two cars were made under name Neuer Vierer (New Fourseater) in year 1901, but later the same car was manufactured under the name type B in 1902 - 1904 (36 made). In 1904 also another variant of the design was made (8 pieces).

The car was initially a four-seater, but later also other variants were made (including 6-seater). The car had rectangular frame, 12 horsepower engine located under the floor, in front of the rear axle. The fuel tank, reservoir for the coolant as well as the radiator were located under the front hood. The steering column with a steering wheel was inclined. The subsequent types C, D, E, F were produced in small numbers. Apart from the E they had flat-four water-cooled engines, transversely mounted, directly under the driver's floorboard.

Noble Automotive

Noble Automotive Ltd., more commonly known simply as Noble, is a British sports car manufacturer based in Leicester. Noble Automotive Ltd. was established in 1999 by Lee Noble in Leeds, West Yorkshire, for producing high-speed sports cars with a rear mid-engine, rear-wheel drive layout. Lee Noble was the chief designer and owner of Noble. He sold the company in August 2006. He resigned from the company in February 2008 and announced his new venture, Fenix Automotive in 2009. The company has since moved to larger premises at Meridian Business Park near Leicester.Noble is a low-production British sports car company, its past products include the M12 GTO, M12 GTO-3, M12 GTO-3R and Noble M400. The M12 GTO-3R and M400 share chassis and body, but have minor differences in engines and suspensions. The M15 has a new space frame chassis. The body and chassis of the Noble is built by Hi-Tech Automotive in Port Elizabeth, South Africa alongside Superformance cars. Once the body shell is completed, it is sent to the Noble factory where the engines, transmissions, etc. are added.

In 2009 Noble released the M600, a car which takes Noble into Hyper Car territory. With 650 bhp (485 kW) available from its purpose built 4.4-litre V8 Volvo twin turbocharged engine with a Yamaha gearbox, the carbon fibre, light weight bodied car is aimed firmly at the established Ferrari/Porsche brands. Deliveries to customers are expected mid-2010. The retail price is GBP 200,000.

Only 220 Noble GTO-3Rs and M400s were exported to the US. They are the only Nobles available to the American market. The US distribution rights to the M12s and M400s were sold in February 2007 to 1G Racing from Ohio. Due to high demand of these cars, 1G released its own copy, named Rossion Q1.

Noble M400

The Noble M400 is a sports car from the British car maker Noble. Manufacturing was outsourced to Hi-Tech Automotive, based in Port Elizabeth, South Africa. The M400 was noted by the automotive press for excellent handling and power.

Peugeot 908 RC

The Peugeot 908 RC is a concept car produced by the French car manufacturer Peugeot and first shown to the public at the 2006 Paris Motor Show.

The 908 RC is a luxury four-door limousine powered by the 5.5L V12 HDi diesel from the 908 HDi FAP sportscar installed centrally and transversally, producing 700 bhp (522 kW; 710 PS), 1,200 N⋅m (885 lb⋅ft) torque and with a claimed top speed of 186 mph (299.3 km/h). The 908 RC is fitted with a six-speed sequential gearbox, with power to the rear wheels.The 908 RC sits a long 3,150 mm (124 in) wheelbase, has a length of 5,123 mm (201.7 in), and is 1,370 mm (54 in) high. The suspension is front and rear drop link with double wishbone suspension, the brakes are carbon ceramic discs made by Brembo.

Porsche 910

The Porsche 910 or Carrera 10 was a race car from Porsche, based on the Porsche 906. 29 were produced and were raced in 1966 and 1967. The factory name for the 910 was the 906/10. The 910 was considered the next sequence in the 906 line.

RMR

RMR may refer to:

RMR layout (of an automobile), see rear mid-engine, rear-wheel-drive layout

Recurring Monthly Revenue, a measure of customer attrition

Registered Merit Reporter, a certification offered by the National Court Reporters Association

Resting metabolic rate, see basal metabolic rate

Revelstoke Mountain Resort, a Canadian ski resort located in Revelstoke, British Columbia

Rock mass rating, a rock mass classification system (geotechnical engineering)

RockMyRun, a running/workout mobile app

Royal Marines Reserve, the volunteer reserve force used to augment the regular Royal Marines

The Royal Montreal Regiment, a Canadian Forces infantry regiment based in Montreal

Rick Mercer Report, a Canadian comedy television series

Ruggedized miniature reflex (optics), a type of weapon-mounted red dot sight for guns

RMR (revolver), a .357 double-action revolver

Rear-wheel drive

Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, where the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars.

Most rear-wheel drive vehicles feature a longitudinally mounted engine at the front of the car.

Suzuki MR Wagon

The Suzuki MR Wagon is a 4-seater mini MPV manufactured by Suzuki for the Japanese market only, and also marketed in Japan by Nissan as the Nissan Moco under an OEM agreement. The model debuted in 2001, and since 2011 it has been in its third generation. It was launched in India by Maruti Suzuki as Maruti Zen Estilo in 2006, Maruti Zen Estilo was discontinued in 2009 and renamed as Maruti Estilo.

The vehicle's name is somewhat misleading, as it does not sport a rear mid-engine, rear-wheel drive layout (which is often abbreviated as RMR, or more commonly, MR). However, the name "Moco" was changed in some countries because of the Spanish language meaning of the word "moco" ("snot" or "booger").

Ultima Mk1

The Ultima Mk1 is a mid-engined concept kit car produced by Noble Motorsport Ltd in 1983 (the company later became Ultima Sports when Ted Marlow and Richard Marlow bought the rights in 1992). The Mk1 was intended to go into production, but before any sold the Ultima Mk2 was introduced, and thus only one Mk1 was made.

VUHL 05

The VUHL 05 (pronounced ‘vool’, ‘oh five’) is a lightweight sports car in the B-segment, first presented in 2013 at the Royal Automobile Club in London. At the beginning of its production, the car was assembled in Canada, tested in the United States and United Kingdom and returned to Mexico, where the final detail work was done, In July 2015, the production of the vehicle was set up at a new plant in Querétaro.

Venturi Fétish

The Venturi Fétish is a two-seater electric sports car. Unveiled for the first time in 2004, the Fétish is the first sports car specifically designed to be electric. It has been produced by Venturi in Monaco since 2006, and the design of the car was done by the Parisian designers Sacha Lakic. When it went into production, it was the first electrically-powered production sports car in the world.Before its electric version, a petrol version of the same vehicle (fitted with a Renault petrol engine) was introduced in concept form at the 2002 Geneva Motor Show, and was also shown at the 2002 Paris Motor Show and the 2003 North American International Auto Show.

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