This is a Benz RH Tropfenwagen
The following stolen from grandprixhistory.org
Car: Benz Engine: Inline 6 Cylinder Maker: Tropfenwagen Typ RH (RH = Rennwagen mitt Heckmotor) Bore X Stroke: 65 mm x 100 mm Year: 1923 Capacity: 1991 cc Class: Grand Prix Power: 90 hp at 4500 rpm Wheelbase: 2830 mm Track: Front: 1400 mm Rear: 1300 mm Notes: 4-speed gearbox, Max Speed 185 kph, Weight 745 kg
In 1921 after World War I, Rumpler surprised visitors at the Berliner Automobile Ausstellung with his revolutionary ‘Tropfenwagen’ (teardrop vehicle), that resembled the gondola of a Zeppelin airship. Edmund Rumpler, was an Austrian automotive engineer who was well-known in post-war Germany as the manufacturer of the successful ‘Taube’ (Pigeon), a German warplane based on an original design by Igo Etrich. Rumpler also had experience in automobile design and manufacturing. In 1903, he had patented a swing axle rear suspension system. Rumpler’s efforts produced a car with an astoundingly low drag coefficient of only 0.28 (when tested in 1979). Its original rear-engine layout combined with independent rear suspension foreshadowed the future.
Rumpler’s concept was of historic significance but most people did not know what to make of this strange vehicle, one exception was Benz’s Berlin representative, Willy Walb, future race team manager at Auto Union who was intrigued by it’s possibilities. He convinced Benz to look at building cars with a similar design both for commercial and racing purposes. Karl Ludvigsen: “Edmund Rumpler and his patent lawyers caused Max Wagner some sleepless nights. Not having a Rumpler license agreement, Benz had to use a rear suspension design that wouldn’t contravene Rumpler’s many patents. As a result the RH had a much more practical system. Its conventional differential was fixed on the frame. It drove the axle half-shafts through universal joints in spherical housings similar to those then widely used for the forward mounting of torque-tube axles.”
Developed under the guidance of chief engineer Hans Nibel, the Benz Typ RH had an advanced twin-ohc in-line six engine with 24 valves, electron pistons, twin Zenith carburetors, a built-up roller-bearing crankshaft, and roller big ends, which gave some 90bhp at 4500rpm, unblown. This engine was located between the cockpit (which enveloped the driver and riding mechanic), and the rear axle, which it drove through a three-speed gearbox mounted as a unit. Inboard rear brakes were employed, a separate crescent-shaped radiator was mounted above the engine cover, and the car had excellent stream-lining with a clean, rounded nose and tapering tail. The radiator mimicking the tall airboxes that are used in modern Formula One cars.
The car competed in only one major race, the Grand Prix of Europe at Monza on September 9, 1923. Three cars were entered for Fernando Minoia, Franz Hörner and Willy Walb. Two of the three cars finished with Minoia in fourth and Hörner in fifth though they were both waved off before they could finish the race due to the track being invaded by spectators. The cars were known for their handling but were underpowered when compared to the supercharged Fiats. Perhaps if a blown engine had been used the results might have been different. As a small consolation the Monza organizers awarded Benz a medallion for their audacious design. The cars later competed in local events in Germany with a handful of hillclimb victories by Walb and later Mercedes works driver Adolf Rosenberger to their credit. On May 16th 1925 Rosenberger won the Tropfenwagen’s final race, the Rund um die Solitude and Benz’s rear-engined experiment was over. Despite their promising start at Monza, these Teardrop racers were not very successful in later Grand Prix and the company returned to building front-engined cars. However, there is little doubt that when Ferdinand Porsche became technical director of Mercedes in 1924, he must have carefully studied all the construction details of this unconventional rear-engined racer some aspects of which served as a model for Porsche’s use of swing-axles and a mid-placed engine layout in his future Auto Union race car.
The Rumpler Tropfenwagen (“Rumpler drop car”, named after its raindrop shape) was a car developed by Austrian engineer Edmund Rumpler.
Rumpler, born in Vienna, was known as a designer of aircraft when at the 1921 Berlin car show he introduced the Tropfenwagen. It was to be the first streamlined production car, before the Chrysler Airflow and Tatra T77. The Rumpler had a drag coefficient of only 0.28, a measurement which astonished later engineers and would be competitive even today. For comparison: the top ten most aerodynamic production cars in 2014/2015 worked their way down from a value of 0.26. The Fiat Balilla of the mid-1930s, by contrast, was rated at 0.60.
To enable the car’s aerodynamic shape, the Tropfenwagen also featured the world’s first (single plane) curved windows. Both the windscreen and the side windows were significantly curved.
The car featured a Siemens and Halske-built 2,580 cc (157 cu in) overhead valve W6 engine, with three banks of paired cylinders, all working on a common crankshaft. Producing 36 hp (27 kW), it was mounted just ahead of the rear axle. The engine, transmission, and final drive were assembled together and installed as a unit. The Rumpler-invented rear swing axles were suspended by trailing leaf springs, while the front beam axle was suspended by leading leaf springs.
Able to seat four or five, all the passengers were carried between the axles for maximum comfort, while the driver was alone at the front, to maximize view. With the 1923 model, two tip-up seats were added.
Weighing nearly 3,000 lb (1,361 kg), the Tropfenwagen was nevertheless capable of 70 mph (110 km/h) on its mere 36 hp (27 kW). This performance got the attention of Benz & Cie.’s chief engineer, Hans Nibel. Nibel conceived the Mercedes-Benz Tropfenwagen racers using the virtually unchanged Rumpler chassis. Poor sales and increasing losses led Benz to abandon the project. Later Auto Union racing cars resembled the Benz Tropfenwagen racers and were built in part by Rumpler engineers.
Rumpler made another attempt in 1924, the 4A106, which used a 50 hp (37 kW) 2,614 cc (159.5 cu in) inline 4-cylinder engine. This compelled a growth in wheelbase, with a consequent increase in seating to six or seven.
Although the car was very advanced for its time, it sold poorly – about 100 cars were built. Sales were hindered by small problems at the start (cooling, steering), the appearance of the vehicle, and the absence of a luggage compartment. Most were sold as taxis, where easy boarding and the high ceiling were advantages. The last cars were built in 1925.
The Tropfenwagen did become famous thanks to the film Metropolis, in which Rumplers found a burning end. It also inspired the Mercedes-Benz 130H / 150H / 170H road cars.
Only two examples are known to survive, one in the Deutsches Museum’s Verkehrszentrum in Munich and one in the Deutsches Technikmuseum Berlin.
Such innovation. So nice.