Editing Mid-engine design

{{Short description|Automobile design in which the engine is placed between the front and rear axles}}
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{{original research|date=March 2018}}{{More citations needed|date=September 2018}}
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{{redirect|Midship|the nautical expression|Midships}}
[[File:Haryanto Bahrain 2016.jpg|thumb|Formula One cars use rear-mid engine rear wheel drive design.]]
In [[automotive engineering]], a '''mid-engine layout''' describes the placement of an [[automotive engine|automobile]] [[internal combustion engine|engine]] in front of the rear-wheel [[axle]]s, but behind the front axle.

==History==
The mid-engine, rear-wheel-drive format can be considered the original layout of automobiles.{{Citation needed|date=February 2018}} A 1901 [[Autocar_Company|Autocar]] was the first gasoline-powered automobile to use a [[drive shaft]] and placed the engine under the seat. This pioneering vehicle is now in the collection of the [[Smithsonian Institution]].<ref>{{Cite web | url=http://amhistory.si.edu/onthemove/collection/object_1273.html |title = America on the Move|date = 2016-11-02}}</ref>

==Benefits==
[[Image:Lotus Europe series 1 1967.jpg|right|thumb|The [[Lotus Europa]] S1 was based on a prototype built to compete for Henry Ford II's contract to build a Le Mans race car in the early 1960s.]]

Mounting the engine in the middle instead of the front of the vehicle puts more weight over the rear tires, so they have more traction and provide more assistance to the front tires in braking the vehicle, with less chance of rear-wheel lockup and less chance of a skid or [[Spinout (driving)|spin out]]. If the mid-engine vehicle is also rear-drive the added weight on the rear tires can also improve acceleration on slippery surfaces, providing much of the benefit of [[all-wheel-drive]] without the added weight and expense of all-wheel-drive components. The mid-engine layout makes ABS brakes and traction control systems work better, by providing them more traction to control. The mid-engine layout may make a vehicle safer since an accident can occur if a vehicle cannot stay in its own lane around a curve or is unable to stop quickly enough. Mid-engine design is also a way to provide additional empty crush space in the front of the automobile between the bumper and the windshield, which can then be designed to absorb more of the impact force in a frontal collision in order to minimize penetration into the passenger compartment of the vehicle.

In most automobiles, and in sports cars especially, ideal [[car handling]] requires balanced traction between the front and rear wheels when cornering, in order to maximize the possible speed around curves without sliding out. This balance is harder to achieve when the heavy weight of the engine is located far to the front or far to the rear of the vehicle. Some automobile designs strive to balance the fore and aft weight distribution by other means, such as putting the engine in the front and the gearbox and battery in the rear of the vehicle.

Another benefit comes when the heavy mass of the engine is located close to the back of the seats. It makes it easier for the suspension to absorb the force of bumps so the riders feel a smoother ride. But in sports cars, the engine position is once again used to increase performance and the potentially smoother ride is usually more than offset by stiffer [[shock absorber]]s.

This layout also allows the motor, gearbox, and differential to be bolted together as a single unit. Together with independent suspension on the driven wheels, this removes the need for the chassis to transfer engine torque reaction.

==Drawbacks==
[[Image:Unterflurmotor Hanomag.jpg|thumb|225px|Underfloor mid-engine in a historical [[Hanomag]] truck chassis.]]
The largest drawback of mid-engine cars is restricted rear or front (in the case of front-mid layouts) passenger space; consequently, most mid-engine vehicles are two-seat vehicles.  The engine in effect pushes the rear passenger seats forward towards the front [[axle]] (if the engine is behind the driver). Exceptions typically involve larger vehicles of unusual length or height in which the passengers can share space between the axles with the engine, which can be between them or below them, as in some vans, large trucks, and buses. The mid-engine layout (with a horizontal engine) was common in single-decker buses in the 1950s and 1960s, e.g. the [[AEC Reliance]]. The [[Ferrari Mondial]] is to date the only successful example of a true mid-engined convertible with seating for 4 and sports car/supercar performance.  A version of the [[Lotus Evora]] with a removable roof panel is anticipated but no definite date is known.

Like any layout where the engine is not front-mounted and facing the wind, the traditional "engine-behind-the-passengers" layout makes engine cooling more difficult.  This has been a problem in some cars,{{Citation needed|date=September 2011}} but this issue seems to have been largely solved in newer designs. For example, the [[Saleen S7]] employs large engine-compartment vents on the sides and rear of the bodywork to help dissipate heat from its very high-output engine.

Mid-engined cars are more dangerous than front-engined cars if the driver loses control - although this may be initially harder to provoke due to the superior balance - and the car begins to spin.  The moment of inertia about the center of gravity is low due to the concentration of mass between the axles (similar to standing in the middle of a playground roundabout, rather than at the edge) and the spin will occur suddenly, the car will rotate faster and it will be harder to recover from.  Conversely, a front-engined car is more likely to break away in a progressive and controllable manner as the tires lose traction.

==Variations==
Super, sport, and race cars frequently have a mid-engined layout, as these vehicles' [[car handling|handling]] characteristics are more important than other requirements, such as usable space. In dedicated sports cars, a [[weight distribution]] of about 50% front and rear is frequently pursued, to optimise the vehicle's driving dynamics – a target that is typically only achievable by placing the engine somewhere between the front and rear axles. Usually, the term "mid-engine" has been primarily applied to cars having the engine located between the driver and the ''rear'' drive axles. This layout is referred to as [[Rear mid-engine, rear-wheel-drive layout|rear mid-engine, rear-wheel drive]], (or RMR) layout. The mechanical layout and packaging of an RMR car are substantially different from that of a front-engine or rear-engine car.

When the engine is in front of the driver, but fully ''behind'' the front axle line, the layout is sometimes called a front mid-engine, rear-wheel-drive, or [[FMR layout]] instead of the less-specific term front-engine; and can be considered a subset of the latter. In-vehicle layout, FMR is substantially the same as FR, but handling differs as a result of the difference in weight distribution. 

Some vehicles could be classified as FR or FMR depending on the factory-installed engine (I4 vs I6).  Historically most classical FR cars such as the Ford Models T and A would qualify as an FMR engine car.  Additionally, the distinction between FR and FMR is a fluid one, depending on the degree of engine protrusion in front of the front axle line, as manufacturers mount engines as far back in the chassis as possible.  Not all manufacturers use the Front-Mid designation.

==Examples==

==={{anchor|FMR}}FMR layout – ''Front Mid-engine / Rear-wheel drive''===
{{Main|Front-engine, rear-wheel-drive layout#Front mid-engine, rear-wheel-drive layout|l1=Front mid-engine, rear-wheel-drive layout}}
[[Image:Automotive diagrams 03 En.png|thumb|275px|Front mid-engine position / Rear-wheel drive]]
[[Image:1929_Bentley_front_34_right.jpg|thumb|275px|Front mid-engine position / Rear-wheel drive]]

These cars are RWD cars with the engine placed between the driver and the front axle. 
* [[Alfa Romeo 8C Competizione]]
* [[AC Cobra]]
* [[Aston Martin Vanquish]], [[Aston Martin Vantage (2005)|Vantage (2005)]], [[Aston Martin Vantage (2018)|Vantage (2018)]], [[Aston Martin DB7|DB7]], [[Aston Martin DB9|DB9]], [[Aston Martin DB11|DB11]], [[Aston Martin DB12|DB12]], [[Aston Martin DBS V12|DBS V12]], [[Aston Martin DBS Superleggera|DBS Superleggera]], [[Aston Martin Virage#Virage (2011–2012)|Virage (2011–2012)]]
* [[BMW Z1]], [[BMW Z8|Z8]], [[BMW M8 GTE|M8 GTE]]
* [[Chevrolet Corvette]] ([[Chevrolet Corvette (C2)|second]] through [[Chevrolet Corvette (C7)|seventh generations]])
* [[Bill Thomas Cheetah]] (used only one [[universal joint]] between [[Transmission (mechanics)|transmission]] tailshaft housing and [[Differential (mechanical device)|differential]] housing)
* [[Dodge A100]] and [[Dodge Viper|Viper]]
* [[Excalibur (automobile)|Excalibur]] SSK, SS Roadster and SS Phaeton
* [[Ferrari 250 GTO]], [[Ferrari 599|599 GTB Fiorano]], [[Ferrari 612 Scaglietti|612 Scaglietti]], [[Ferrari F12|F12 Berlinetta]], [[Ferrari 812 Superfast|812 Superfast]], [[Ferrari GTC4Lusso#GTC4Lusso T|GTC4Lusso T]], [[Ferrari California|California]], [[Ferrari Portofino|Portofino]], [[Ferrari Roma|Roma]] and [[Ferrari 12Cilindri|12Cilindri]]
*[[Ford E-Series#First generation (1961–1967)|Ford Econoline]] (first generation)
* [[Honda S2000]]
* [[Jaguar E-Type]]
* [[Lexus LFA]]
* [[Maserati Quattroporte V]], [[Maserati GranTurismo|GranTurismo]]/[[Maserati GranTurismo#GranCabrio|GranCabrio]]
* [[Mazda Bongo#Second generation (1977–1983)|Mazda Bongo]] (second generation), [[Mazda RX-7|RX-7]], [[Mazda MX-5|MX-5]] (NC and ND) and [[Mazda RX-8|RX-8]]
* [[Mercedes-Benz SLR McLaren]], [[Mercedes-Benz SLS AMG|SLS AMG]] and [[Mercedes-AMG GT|AMG GT]]
* [[Morgan +4]], [[Morgan 4/4|4/4]], [[Morgan Aero 8|Aero 8]], [[Morgan Plus Four|Plus Four]], [[Morgan Plus Six|Plus Six]] and [[Morgan Plus 8|Plus 8]]
* [[Opel GT]] (original)
* [[Shelby Daytona]]
* [[Toyota Previa]] (first generation) and [[Toyota 2000GT|2000GT]]

* Most pre–World War II front-engine rear-wheel-drive cars

==={{anchor|FM4}}FM4 layout – ''Front Mid-engine / Four-wheel drive''===
[[Image:Covered Willy's jeep Wings Over Wine Country 2007.JPG|thumb|275px|Front mid-engine position / Four-wheel drive]]
This layout, similar to the above FMR layout, with the engine between driver and the front axle, adds front-wheel drive to become a four-wheel drive.  An engineering challenge with this layout is getting the power to the front wheels past the engine - this would normally involve raising the engine to allow a [[propshaft]] to pass under the engine, or in the case of the [[Ferrari FF]] taking power from both ends of the [[crankshaft]] with two separate gearboxes. 
*[[Toyota Previa]] [[All-Trac]] variant
*[[Ferrari FF]], [[Ferrari GTC4Lusso|GTC4Lusso]] and [[Ferrari Purosangue|Purosangue]]
*[[Jensen FF]]
*[[Hummer H1]]
*[[Willys MB]]
*[[Nissan GT-R]]
* Most early front-engine off-road cars

==={{anchor|RMR}}RMR layout – ''Rear Mid-engine / Rear-wheel drive''===
[[Image:Automotive diagrams 04 En.png|thumb|275px|Rear mid-engine position / Rear-wheel drive]]
{{main|Rear mid-engine, rear-wheel-drive layout}}
These cars use a traditional engine layout between driver and rear drive axle. Typically, they're simply called MR; for ''mid-rear'' (engined), or '''mid-engine, rear-wheel-drive''' layout cars.
* [[Alfa Romeo 4C]]
* [[Alpine A110 (2017)]]
* [[Apollo Intensa Emozione]]
* [[Ariel Atom]]
* [[Aston Martin Valkyrie]]
* [[Autozam AZ-1]]
* [[BMW M1]]
* [[Chevrolet Corvette (C8)]]
* [[Consulier GTP]]
* [[De Tomaso Vallelunga|DeTomaso Vallelunga]], [[De Tomaso Mangusta|Mangusta]], [[De Tomaso Pantera|Pantera]], [[De Tomaso Guarà|Guarà]]
* [[Ferrari 250 LM]], [[Ferrari 308 GTB/GTS|308]], [[Ferrari 328|328]], [[Ferrari 348|348]], [[Ferrari F355|F355]], [[Ferrari 360|360]], [[Ferrari F430|F430]], [[Ferrari 458|458]], [[Ferrari 488|488]], [[Ferrari F8|F8]], [[Ferrari 296|296 GTB]], [[Ferrari Berlinetta Boxer|Berlinetta Boxer]], [[Ferrari Mondial|Mondial]], [[Ferrari Testarossa|Testarossa]], [[Ferrari F40|F40]], [[Ferrari F50|F50]], [[Ferrari Enzo|Enzo]], [[Ferrari FXX|FXX]], [[LaFerrari]], [[Ferrari FXX-K|FXX-K]]
* [[Fiat X1/9]]
* [[Ford GT]] and [[Ford GT40|GT40]]
* [[Gordon Murray Automotive T.33]], [[Gordon Murray Automotive T.50|T.50]]
* [[Ginetta F400]], [[Ginetta G60|G60]]
* [[Honda Beat]], [[Honda NSX (first generation)|NSX (NA1/NA2)]], [[Honda S660|S660]], [[Honda Acty]] (2WD models only)
* [[Jaguar XJR-15]] and [[Jaguar XJ220|XJ220]]
* [[Koenigsegg CC8S]], [[Koenigsegg CCR|CCR]], [[Koenigsegg CCX|CCX]], [[Koenigsegg Agera|Agera]], [[Koenigsegg Regera|Regera]], [[Koenigsegg Jesko|Jesko]]
* [[Lamborghini Miura]], [[Lamborghini Countach|Countach]], [[Lamborghini Diablo SV|Diablo SV]]
* [[Lancia Stratos]], [[Lancia Montecarlo|Montecarlo]]
* [[Lotus Europa]], [[Lotus Esprit|Esprit]], [[Lotus Elise|Elise]], [[Lotus Exige|Exige]], [[Lotus Evora|Evora]], [[Lotus Emira|Emira]]
* [[Maserati Merak]], [[Maserati Bora|Bora]], [[Maserati MC12|MC12]], [[Maserati MC20|MC20]]
* [[Matra Djet]], [[Matra 530|530]], [[Matra Bagheera|Bagheera]], [[Matra Murena|Murena]]
* [[McLaren F1]], [[McLaren 12C|MP4-12C]], [[McLaren 570S|570S]], [[McLaren 650S|650S]], [[McLaren 720S|720S]], [[McLaren P1|P1]], [[McLaren GT|GT]], [[McLaren Artura|Artura]], [[McLaren Senna|Senna]], [[McLaren Speedtail|Speedtail]], [[McLaren Elva|Elva]]
* [[Mercedes-Benz CLK GTR]]
* [[MG F / MG TF]]
* [[Mitsubishi i]] and [[Mitsubishi i-MiEV|i-MiEV]] (Rear Mid-engine transversely-mounted / Rear-wheel drive)
* [[Opel Speedster]]
* [[Pagani Huayra]], [[Pagani Zonda|Zonda]], [[Pagani Utopia|Utopia]]
* [[Pontiac Fiero]]
* [[Porsche 550]], [[Porsche 914|914]], [[Porsche Boxster/Cayman|Boxster/Cayman]], [[Porsche Carrera GT|Carrera GT]], [[Porsche 911 GT1|911 GT1]]
* [[Renault 5 Turbo]], [[Clio V6 Renault Sport]]
* [[Secma F16]]
* [[Smart Roadster]]
* [[Tatra 602]]
* [[Toyota MR2|Toyota MR2/MR-S]]
* [[Venturi Atlantique]]
* [[Volkswagen 1-litre car|Volkswagen XL1]]

==={{anchor|M4}}M4 layout – ''Rear Mid-engine / Four-wheel drive''===
{{main|Mid-engine, four-wheel-drive layout}}
These cars use mid-ship, [[four-wheel drive|four-wheel-drive]], with an engine between the axles.

*[[Ares Design Project1]]
*[[Audi R8]]
*[[BMW i8]]
*[[Bugatti EB 110]], [[Bugatti Veyron|Veyron]], [[Bugatti Chiron|Chiron]], [[Bugatti Divo|Divo]], [[Bugatti Centodieci|Centodieci]]
*[[Ford RS200]]
*[[Ferrari SF90 Stradale]]
*[[Honda Acty]] (4WD versions only), [[Honda NSX (second generation)|NSX (NC1)]], [[Honda Z#1998-2002|Z]] (1998-2002)
*[[Italdesign Zerouno]]
*[[Koenigsegg Gemera]]
*[[Lancia Delta S4]]
*[[Lamborghini Aventador]], [[Lamborghini Centenario|Centenario]], [[Lamborghini Sián FKP 37|Sián FKP 37]], [[Lamborghini Countach LPI 800-4|Countach LPI 800-4]], [[Lamborghini Diablo|Diablo VT series]], [[Lamborghini Gallardo|Gallardo]], [[Lamborghini Murciélago|Murciélago]], [[Lamborghini Reventón|Reventón]], [[Lamborghini Huracán|Huracán]], [[Lamborghini Sesto Elemento|Sesto Elemento]]
*[[Mercedes-AMG ONE]]
*[[MG Metro 6R4]]
*[[Panther Solo#Solo 2|Panther Solo 2]]
*[[Peugeot 205#205 Turbo 16 (T16)|Peugeot 205 Turbo 16]]
*[[Porsche 918 Spyder]]
*[[Volvo L3314]]
*[[Unimog#2000s|Unimog UGN/405]]

==={{anchor|FMF}}FMF layout – ''Front Mid-engine / Front-wheel drive''===
[[Image:Automotive diagrams 07 En.png|thumb|275px|Front mid-engine position / Front-wheel drive]]
{{main|Front-mid-engine, front-wheel-drive layout}}
These cars are "mid-ship engined" vehicles, but they use [[front-wheel drive]], with the engine in front of the driver. It is still treated as an FF layout, though, due to the engine's placement still being in the front of the car, contrary to the popular belief that the engine is placed in front of the rear axle with power transferred to the front wheels (an RMF layout). In most examples, the engine is longitudinally mounted rather than transversely as is common with FF cars.

* [[BSA Scout]]
* [[Citroën Traction Avant]], [[Citroën DS|DS]], [[Citroën SM|SM]]
* [[Nissan GT-R LM Nismo]]
* [[Renault 4]], [[Renault 5|5]], [[Renault 16|16]]
* [[Saab Sonett]] Mk1
* [[Honda Vigor#Third generation|Honda Vigor]]/[[Honda Inspire#First generation|Inspire]] 1989–1995
* [[Maserati Quattroporte II]]

== See also ==
*[[Front-engine design]]
*[[Rear-engine design]]

== References ==
{{reflist|2}}

{{Automobile configuration}}

{{DEFAULTSORT:Mid-Engine Design}}
[[Category:Mid-engined vehicles| ]]
[[Category:Car layouts]]