Rear-engine design
Encyclopedia
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 past 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.
Rear-engined cars are almost always rear wheel drive, a layout known as RR
. The exception is certain high performance four wheel drive
models from some European automakers.
This layout is chosen for three reasons - packaging, traction, and ease of manufacture:
The disadvantage of the rear engine configuration, is that placing the engine outside the wheelbase
can create problems for car handling
as, when the car begins to slide on a corner, the end of the car will tend to want to swing wide and overtake the front — especially under braking. This tendency is referred to as oversteer and creates potential safety issues both for ordinary drivers, and even in racing applications. There are also occasions where expert drivers find such behavior desirable in drifting
, a motorsport based on intentional oversteer. Details on the handling characteristics of rear-engined cars were prominently featured in the 1965 book Unsafe at Any Speed
.
In addition, even though the rear wheels benefit from the additional traction the added weight of the engine gives, the front wheels still need traction in order to steer the car effectively. For this reason, a rear-engined car can also be prone to understeer
.
Although this layout was once popular, it was mainly found in small, inexpensive cars and light commercials, most car makers have abandoned the rear-engined layout apart from Porsche
who has gradually developed their design with improvements to the suspension and chassis to reduce the shortcomings of the layout to exceptional levels in road and race cars.
The most popular current applicaton of this layout is in Low-floor bus
es where its spacesaving attributes are best applied.
On the De Lorean
, to compensate for the uneven (35/65) weight distribution caused by the rear-mounted engine, the car had rear wheels with a diameter slightly greater than the front wheels.
Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
at the rear of the vehicle. The center of gravity
Center of gravity
In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...
of the engine
Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
itself is past 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.
Rear-engined cars are almost always rear wheel drive, a layout known as RR
RR layout
In automotive design, a 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....
. The exception is certain high performance four wheel drive
Four Wheel Drive
The Four Wheel Drive Auto Company, more often known as Four Wheel Drive or just FWD, was founded in 1909 in Clintonville, Wisconsin, as the Badger Four-Wheel Drive Auto Company by Otto Zachow and William Besserdich.-History:...
models from some European automakers.
This layout is chosen for three reasons - packaging, traction, and ease of manufacture:
- Since the engine is located at an extremity, the rest of the vehicle can be used for passengers and luggage.
- Having the engine located over the driven wheels increase downward pressure which is helpful for grip on loose surfaces.
- The drivetrain can be assembled as a unit and installed easily at the factory - easier than a front wheel drive layout where the driven wheels also steer the car.
The disadvantage of the rear engine configuration, is that placing the engine outside the wheelbase
Wheelbase
In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels.- Road :In automobiles, the wheelbase is the horizontal distance between the center of the front wheel and the center of the rear wheel...
can create problems for car handling
Car handling
Automobile handling and vehicle handling are descriptions of the way wheeled vehicles perform transverse to their direction of motion, particularly during cornering and swerving. It also includes their stability when moving at rest. Handling and braking are the major components of a vehicle's...
as, when the car begins to slide on a corner, the end of the car will tend to want to swing wide and overtake the front — especially under braking. This tendency is referred to as oversteer and creates potential safety issues both for ordinary drivers, and even in racing applications. There are also occasions where expert drivers find such behavior desirable in drifting
Drifting (motorsport)
Drifting refers to a driving technique and to a motorsport where the driver intentionally over steers, causing loss of traction in the rear wheels through turns, while maintaining vehicle control and a high exit speed...
, a motorsport based on intentional oversteer. Details on the handling characteristics of rear-engined cars were prominently featured in the 1965 book Unsafe at Any Speed
Unsafe at Any Speed
Unsafe at Any Speed: The Designed-In Dangers of the American Automobile by Ralph Nader, published in 1965, is a book detailing resistance by car manufacturers to the introduction of safety features, like seat belts, and their general reluctance to spend money on improving safety...
.
In addition, even though the rear wheels benefit from the additional traction the added weight of the engine gives, the front wheels still need traction in order to steer the car effectively. For this reason, a rear-engined car can also be prone to understeer
Understeer
Understeer and oversteer are vehicle dynamics terms used to describe the sensitivity of a vehicle to steering. Simply put, oversteer is what occurs when a car turns by more than the amount commanded by the driver...
.
Although this layout was once popular, it was mainly found in small, inexpensive cars and light commercials, most car makers have abandoned the rear-engined layout apart from Porsche
Porsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....
who has gradually developed their design with improvements to the suspension and chassis to reduce the shortcomings of the layout to exceptional levels in road and race cars.
The most popular current applicaton of this layout is in Low-floor bus
Low-floor bus
A low-floor bus is a bus that has no steps between one or more entrances and part or all of the passenger cabin. Being low floor improves the accessibility of the bus for the public, particularly the elderly or infirm, or those with push chairs, and increasingly, those in wheelchairs.In the modern...
es where its spacesaving attributes are best applied.
On the De Lorean
De Lorean Motor Company
The original DeLorean Motor Company was a short-lived automobile manufacturer formed by automobile industry executive John DeLorean in 1975. It is remembered for the one model it produced — the distinctive stainless steel DeLorean DMC-12 sports car featuring gull-wing doors — and for its brief and...
, to compensate for the uneven (35/65) weight distribution caused by the rear-mounted engine, the car had rear wheels with a diameter slightly greater than the front wheels.
Some rear-engined cars
- BMWBMWBayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...
600BMW 600The BMW 600 is a four-seat microcar produced by BMW from mid-1957 until November 1959. Partially based on the BMW Isetta two-seater, it was BMW's first postwar four seat economy car...
and 700BMW 700The BMW 700 was a small rear-engined car produced by BMW in various models from August 1959 to November 1965. It was the first BMW automobile with a monocoque structure. The 700 was a sales success at a time when BMW was close to financial ruin... - ChevroletChevroletChevrolet , also known as Chevy , is a brand of vehicle produced by General Motors Company . Founded by Louis Chevrolet and ousted GM founder William C. Durant on November 3, 1911, General Motors acquired Chevrolet in 1918...
CorvairChevrolet Corvair-First generation :The 1960 Corvair 500 and 700 series four-door sedans were conceived as economy cars offering few amenities in order to keep the price competitive, with the 500 selling for under $2,000... - De Lorean DMC-12De Lorean DMC-12The DeLorean DMC-12 is a sports car originally manufactured in Dunmurry, a suburb west of Belfast, Northern Ireland by John DeLorean's DeLorean Motor Company for the American market in 1981-82. Most commonly known as the DeLorean, it was the only model produced by the company which would go into...
- Dune buggies such as the Meyers ManxMeyers ManxThe Meyers Manx dune buggy was designed by Californian engineer, artist, boat builder and surfer Bruce Meyers. It was produced by his company between 1964 and 1971.The car featured a fiberglass bodyshell coupled with the Volkswagen Beetle frame and engine...
- FIATFiatFIAT, an acronym for Fabbrica Italiana Automobili Torino , is an Italian automobile manufacturer, engine manufacturer, financial, and industrial group based in Turin in the Italian region of Piedmont. Fiat was founded in 1899 by a group of investors including Giovanni Agnelli...
500Fiat 500The Fiat 500 is a car produced by the Fiat company of Italy between 1957 and 1975, with limited production of the Fiat 500 K estate continuing until 1977. The car was designed by Dante Giacosa....
, 600Fiat 600The Fiat 600 is a city car produced by the Italian automaker Fiat from 1955 to 1969. Measuring only 3.22 m long, it was the first rear-engined Fiat and cost the equivalent of about € 6,700 or US$ 7300 in today's money . The total number produced from 1955 to 1969 at the Mirafiori...
, 850Fiat 850The Fiat 850 is a small longitudinal-rear-engined rear wheel drive car which was produced between 1964 and 1973.-Overview:Its technical design was an evolution of the very successful Fiat 600. The internal name for the Fiat 600 development project was "Project 100" and consequently, the internal...
, 126Fiat 126The Fiat 126 is a city car introduced in October 1972 at the Turin Auto Show as a replacement for the Fiat 500. Most were produced in Bielsko-Biała, Poland as the Polski Fiat 126p until 2000...
and 133 - Hillman ImpHillman ImpThe Hillman Imp is a compact, rear-engined saloon car that was manufactured under the Hillman marque by the Rootes Group from 1963 to 1976...
- NSUNSU Motorenwerke AGNSU Motorenwerke AG, normally just NSU, was a German manufacturer of automobiles, motorcycles and pedal cycles, founded in 1873. It was acquired by Volkswagen Group in 1969...
PrinzNSU PrinzThe NSU Prinz is an automobile produced in West Germany by the NSU Motorenwerke AG. The car was built from 1957 to 1973, and received a model change in 1961 .-NSU Prinz 30:... - Porsche 356Porsche 356The Porsche 356 was the company's first production automobile. It was a lightweight and nimble handling rear-engine rear-wheel-drive 2 door sports car available in hardtop coupe and open configurations. Design innovations continued during the years of manufacture, contributing to its motorsports...
, 911Porsche 911The Porsche 911 is a luxury 2-door sports coupe made by Porsche AG of Stuttgart, Germany. It has a distinctive design, rear-engined and with independent rear suspension, an evolution of the swing axle on the Porsche 356. The engine was also air-cooled until the introduction of the Type 996 in 1998...
and 959Porsche 959The Porsche 959 is a sports car manufactured by Porsche from 1986 to 1989, first as a Group B rally car and later as a legal production car designed to satisfy FIA homologation regulations requiring that a minimum number of 200 street legal units be built.... - Mercedes-Benz 130/150/170HRear-Engine Mercedes-BenzFrom 1931 to 1939, Daimler-Benz AG produced three cars with rear engine as well as a few prototypes...
- Renault 4CVRenault 4CVThe Renault 4CV was an economy car produced by the French manufacturer Renault from August 1947-July 1961. The first French car to sell over a million units, the 4CV was ultimately superseded by the Renault Dauphine....
, DauphineRenault DauphineRenault Dauphine is a rear-engined economy car manufactured by Renault in one body style — a three-box, four-door sedan — as the successor to the Renault 4CV, with over two million examples marketed worldwide during its production from 1956-1967....
, CaravelleRenault CaravelleThe Renault Caravelle is an automobile which was produced by the French manufacturer Renault between 1958 and 1968. Outside of North America and Britain it was, until 1962, marketed under the nameplate Renault Floride.-The Name:...
, R8Renault 8The Renault 8 and Renault 10 are two small family cars produced by the French manufacturer Renault in the 1960s and early 1970s....
, R10Renault 8The Renault 8 and Renault 10 are two small family cars produced by the French manufacturer Renault in the 1960s and early 1970s.... - Renault AlpineAlpine (car)Alpine was a French manufacturer of racing and sports cars that used rear-mounted Renault engines.Jean Rédélé , the founder of Alpine, was originally a Dieppe garage proprietor, who began to achieve considerable competition success in one of the few French cars produced just after World War...
- Simca 1000Simca 1000The Simca 1000 was a small, rear-engined, four-door saloon manufactured by the French automaker Simca from 1961 to 1978.-The launch:The car was inexpensive and, at the time of launch, quite modern, with a brand-new inline-4 watercooled engine of 944cc...
- ŠkodaŠkoda AutoŠkoda Auto , more commonly known as Škoda, is an automobile manufacturer based in the Czech Republic. Škoda became a wholly owned subsidiary of the Volkswagen Group in 2000, positioned as the entry brand to the group...
1000/1100MB,MBXŠkoda 1000 MBThe Škoda 1000 MB/1100 MB were two variations of a rear-engined, rear-wheel drive car that was produced by Czech manufacturer Škoda Auto in Mladá Boleslav, Czechoslovakia, between 1964 and 1969...
, 100/110, 110R, 105/120/125, 130/135/136, GardeŠkoda GardeThe Škoda Garde is a rear-engined, rear-wheel drive car that was produced by Czech manufacturer Škoda Auto in Kvasiny, Czechoslovakia between 1981 and 1984....
, RapidSkoda RapidThe Škoda Rapid was a coupe designed and built by Škoda in Czechoslovakia between 1984 and 1990. Based on the Škoda 130/135/136 sedan, it was a replacement for the Škoda Garde coupe built between 1981 and 1984 itself based upon the Škoda 105/120 sedan design... - Smart FortwoSmart FortwoThe Smart Fortwo is a rear-engined two-seater city car manufactured by Smart GmbH, introduced at the 1998 Paris Motor Show as the Smart City Coupé, and currently in its second generation...
- Smart RoadsterSmart RoadsterThe Smart Roadster is a two-door sports car first introduced in 2003 by Smart GmbH. Sales of the Roadster and Roadster Coupé met expectations, however warranty claims resulted in a halt of production of both models in November 2005 after 43,091 Roadsters were made...
- Tatra T77 / T87 / T97 / T603 / T613Tatra (car)Tatra is a vehicle manufacturer in Kopřivnice, Czech Republic. The company was founded in 1850 as Schustala & Company later renamed Nesselsdorfer Wagenbau-Fabriksgesellschaft, a wagon and carriage manufacturer, and in 1897 produced the first motor car in central Europe, the Präsident. In 1918, it...
- Toyota MR2Toyota MR2The Toyota MR2 is a two-seat, mid-engined, rear wheel drive sports car produced by Central Motors, a part of Toyota, from 1984 until July 2007 when production stopped in Japan...
- Tucker Torpedo
- Volkswagen BeetleVolkswagen BeetleThe Volkswagen Type 1, widely known as the Volkswagen Beetle or Volkswagen Bug, is an economy car produced by the German auto maker Volkswagen from 1938 until 2003...
, type 3 'pontoon', Karmann Ghia and type 4 (411/412), as well as the VW BusVolkswagen Type 2The Volkswagen Type 2, officially known as the Transporter or Kombi informally as Bus or Camper , was a panel van introduced in 1950 by German automaker Volkswagen as its second car model – following and initially deriving from Volkswagen's first model, the Type 1 , it was given the factory...
and type 181 'Thing'Volkswagen 181The Volkswagen Type 181 "Kurierwagen", popularly known in the United Kingdom as the Trekker , in the United States as the Thing, and in Mexico as the Safari, was a small military vehicle produced by Volkswagen from 1969 to 1983, although civilian sales stopped in 1980... - Tata NanoTata NanoThe Tata Nano is an inexpensive, rear-engined, four-passenger city car built by the Indian company Tata Motors and is aimed primarily at the Indian domestic market....
- Benz Patent motorwagen