Rumpler Tropfenwagen

Rumpler Tropfenwagen
Rumpler Tropfenwagen on display at Deutsches Technikmuseum Berlin.
Overview
Manufacturer	Rumpler
Also called	Tropfen-Auto
Production	1921-1925
Designer	Edmund Rumpler
Body and chassis
Body style	Saloon car
Layout	RMR layout
Powertrain
Engine	2,580 cc (157 cu in) W6 OHV engine
Transmission	3-speed manual

The Rumpler Tropfenwagen ("Rumpler drop car", named after its 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 car (beating the American Chrysler Airflow and Czech Tatra T77). The Rumpler had a drag coefficient of only 0.28, a measurement which astonished later engineers and would be competitive even today. The Fiat Balilla of the mid-1930s, by contrast, was rated at 0.60.

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 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 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.