The Story of the Rear Engined Passenger Car
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The Story of the Rear Engined Passenger car Rumbler Troftenwagen The concept of engine position in the earliest cars is irrelevant as the passengers usually sat on top of the machinery and layout of the latter was dependent on the means of transmitting the engine power to the rear wheels. This led to compact but high cars, but due to the very limited performance was not unduly unstable. Because it made the best use of the technology of the time, the front engine rear wheel drive layout was to become standard about the turn of the century. This allowed a small reduction in height as speed increased and stability became important. For the next thirty years the front engined, rear wheel drive layout was refined resulting in a decrease in height but increasing intrusion of the machinery into the passenger space and the rear seat passengers located over the rear axle. The idea of locating the engine at the rear of the car to overcome this problem was conceived in the nineteen twenties and developed in the thirties. The layout reached a peak of popularity in the nineteen sixties, then fell out of use except for sporting cars after the rise in the popularity of the front wheel drive car. During the period when rear engines cars were produced in millions and one case tens of millions, the engine was usually located outside the wheelbase. It is the cars of this period that I am reviewing here. The vast majority were light cars but there were some notable exceptions as you will see in the following text.The earliest rear engined cars would today be classified as mid engined cars, such as the Rumbler Troftenwagen and the light cars mentioned below. Rumbler Troftenwagen was designed and built in Germany by Edmund Rumbler an aeronautical engineer in 1921. The Burney cars of 1928 were most probably the first true rear engined cars with the engine behind the rear axle to go into very limited production. A Burney Streamline car lightauto.com Page !1 of !22 The Story of the Rear Engined Passenger car A 1914 GKW A Hanomag 2/10ps Kommissbrot There were a few mid rear-engined cars between those first cars and the beginning of the rear engine period proper. The cycle car era produced a notable example in the G.W.K. made in Britain between 1911 and 1930, initially by Grice, Wood and Keiller, at Maidenhead in Berkshire. The transversely mounted rear engine was not the only unusual feature of the car. Throughout their years of production G.W.K cars were always fitted with a friction drive transmission, utilising a friction disk that moved across the face of the flywheel to produce different reduction ratios from 4 to 1 in top to 14 to 1 as the lowest gear. The rest of the car was conventional for it's day. The engine fitted was a 1069cc water-cooled Coventry Climax unit; it weighed 9.5-cwt and cost £150. Production between 1918 and 1930 was not great with nearly 200 examples of various types made. While G.W.K were struggling on in Britain, Hanomag in Germany produced the "2/10ps Kommissbrot", The latter being a popular name given to the car and referring to a loaf of bread. Made from 1924 to 1928 in which time 15,800 examples were produced. It's single cylinder water cooled engine of 500cc was mounted at the rear with three speed gearbox and a chain final drive in an oil bath to the solid rear axle. A two seat car with a 40 mph maximum speed, in most respects it was late example of the cycle car. Limited experiments in front wheel drive and rear engine layouts had been carried out, but the need for a more complex means of transmitting the power to the driven wheels than the almost universally used live axle was the stumbling block. The simplest alternative to the live axle was the swing axle. The swing axle had been used by Hans Ludwinka at Tatra since the early nineteen twenties and Ludwinka was to become one of the pioneers of rear engine cars. The Tatra swing axle didn't use flexible joints but a system of bevel gears that allowed each drive shaft to move independently. The flexible coupling commonly in use at the time was the fabric coupling it had a limited degree of deflection and working life and was not suitable for use with swing axles. The availability of better flexible couplings of the hardy Spicer type made it possible to develop a reliable swing axle transmission. The combination of the rear mounted engine with swing axle transmission proved to be the simplest way to remove the engine and the transmission from the passenger space and lower the overall height of the car. " lightauto.com Page !2 of !22 The Story of the Rear Engined Passenger car The Ardie-Ganz prototype 1933 Standard Superior From 1928 onwards, the idea of a people's car with a rear mounted air-cooled engine, all independent springing and a backbone frame was promoted in Germany by an engineer and journalist Josef Ganz. Ardie a German motorcycle manufacturer produced an experimental car with a forked backbone frame the Ardie Ganz, in 1930. Adler a German manufacturer produced another Ganz prototype in 1931. In 1933 the first of his designs to go in production the Superior was made by Standard Fahrzeugfabrik. It had a mid rear mounted two stroke engine. In 1927 Sir Dennistoun Burney the designer of the airship R100, set up a company to produce aerodynamically efficient cars, Streamline Cars Ltd at "Cordwallis Works", Maidenhead Berkshire England. The prototype of 1928 used an Alvis front wheel drive chassis turn back to front with the steering returned to the front. This was clothed with a teardrop shaped body. The production cars of which there were twelve made between 1929 and 1933 had a space frame chassis with all independent suspension using transverse leaf springs, hydraulic brakes and a variety of engines were used, mounted at the rear behind the rear wheels. This design had a top speed of 80mph. The design was adopted by Crossley Cars in 1933, fitted with 1991cc overhead valve six-cylinder engine. The radiator was moved to the front of the car and a pre-selector gearbox fitted. Only twenty-five examples were produced and that was in 1934. While these few expensive cars were being produced in Britain, in Czechoslovakia and Germany various designs, prototypes and a few production cars were being created. A Rear Engined Crossley lightauto.com Page !3 of !22 The Story of the Rear Engined Passenger car The Zundapp "Volksauto" Chassis and Body Dr Ferdinand Porsche set the engineers in his design bureau on project number 12 at the end of September 1931, the design of an economy car. He didn't have a commission for the car, but this was something he wanted to do for some time. By December 1931 the design for a small car was sufficiently advanced for Porsche to look for a possible manufacturer. The main features of the design were, independent suspension on all four wheels using trailing arms at the front and swing axles at the rear, with Porsche patent torsion- bar springs. A three cylinder air-cooled radial engine that was complete with the gearbox and final drive located at the rear of the chassis behind the rear wheels. The first prototype of the Tatra Type V570 designed by Erich Ledwinka, the son of Tatra's chief engineer Hans Ledwinka was produced in 1931. Although this prototype had a body of conventional form, the inspiration for the rear engined Tatra came from the idea of taking full advantage of the streamlined forms proposed by the aerodynamicist Paul Jarey. By locating the engine in the long tail, a low hood or bonnet line could be achieved. It had a platform chassis and the air-cooled flat twin engine of 845cc; gearbox and final drive was located at its rear. Dr Neumayer head of Zundapp, a German motorcycle company was looking for a small car design to produce and the Porsche project No 12 proved of interest. The result was the Zundapp "Volksauto", project. The major change from the original project was the engine. A one litre capacity five cylinder water-cooled radial engine was fitted. Three prototypes were produced in 1932 and extensively tested but the project didn't continue due to financial and business factors. Tatra 77 Limuzina 1934 The first prototype of the Tatra Type 77 was running by 1932, it was a large car in the manner of the Burney and Crossley with a streamlined body. The three litre air-cooled OHV V8 engine at the rear of a platform chassis drove the rear wheels via Tatra type swing axles, that used a pair of crown wheels and pinions that allowed the half axles to articulate each side of the final drive unit. A double wishbone type of front suspension was fitted and transverse leaf springs were used at front and rear. " lightauto.com Page !4 of !22 The Story of the Rear Engined Passenger car Skoda 932 Tatra Type V570 second prototype Skoda produced the 932 prototype in 1932; it had a backbone chassis with an air-cooled flat four engine at the rear. Skoda didn't develop the design but produced the 420, a front-engined car that had some of the features that were innovative at the time, namely a backbone chassis with swing axle rear suspension.