BMW 303

BMW
BMW 303 Cabriolet (1934)
303
Production period:	1933-1934
Class :	Lower middle class
Body versions :	Limousine , cabriolet
Engines:	Petrol engine : BMW M78 (1182 cm 3 , 22 kW)
Length:	3900 mm
Width:	1440 mm
Height:	1550 mm
Wheelbase :	2400 mm
Empty weight :	820 kg
successor	BMW 315

The BMW 303 was a car that BMW built in its Eisenach plant in 1933/1934. It was the first BMW vehicle with a six-cylinder engine and the kidney-shaped radiator grille that still characterizes the brand's cars to this day.

history

development

In 1931, based on a cooperation agreement with Daimler-Benz , BMW decided to develop a new car with a displacement of up to 1.3 liters and a six-cylinder engine above the successful BMW 3/20 .

engine

At the main plant in Munich , Max Friz designed an engine with overhead valves ( OHV ), an engine block and cylinder head made of an aluminum alloy , which was very advanced for the time ; In Eisenach, however, his former colleague Martin Duckstein designed a conventional design with vertical valves ( SV valve control ) and only three crankshaft bearings . The crankcase and cylinder head were made of gray cast iron .

In the summer of 1932, General Director Popp commissioned the test manager Rudolf Schleicher to assess the competing engine concepts. Then Schleicher and his colleague Karl Rech presented their own design: engine block and cylinder head made of inexpensive gray cast iron, but with four instead of three crankshaft bearings and OHV valve control. It was supplied with a fuel-air mixture by two ascending flow carburetors . Schleicher and Rech introduced the proven and successful modular concept of BMW motorcycles into car construction at BMW. Many parts were the same as in the four-cylinder engine of the BMW 3/20 and therefore the six-cylinder could also be machined on its production machines. American design principles of large-scale construction served as a role model - after all, produced BMW since 1928 the nine-cylinder - aircraft engine BMW Hornet , a manufacture under license of the Pratt & Whitney R-1690 .

Hans Nibel , chief developer at Daimler-Benz and a good friend of Franz Josef Popp, was finally consulted and immediately decided on the design by Schleicher and Rech, which was then implemented.

chassis

The chief designer Fritz Fiedler , who had only switched from Horch in Zwickau to BMW in August 1932 , found a new ladder frame made of open ( U-shaped ) profiles for the 303 in Eisenach , but this did not meet his requirements. In a short time he designed a lighter construction with round longitudinal tubes and box-shaped crossbars . This also made the basis of the chassis trend- setting for the following years.

marketing

BMW presented the Type 303 in February 1933 in Berlin at the 24th International Automobile and Motorcycle Exhibition (IAMA).

A choice of three bodies was offered: a 2-door sedan with 4 seats (RM 3600, -), a 2-door convertible with 4 seats (RM 4400, -) and a 2-door sports convertible with 2 seats (RM 4600 , -).

After 2,300 vehicles had been built, the BMW 315 with a more powerful engine came onto the market in 1934 as a successor.

technology

BMW 303 Cabriolet

engine and gears

Were driven vehicles from a six-cylinder in-line engine (constructed by Rudolf Schleicher) with 1173 cc displacement, the at 4000 min ^-1 issued a power of 30 HP (22 kW). The engine power was transmitted to the rear wheels via a four-speed gearbox with center shift. The top speed was 90 km / h.

Body and chassis

The front wheels were suspended individually : the double wishbone axle consisted of an upper transverse leaf spring and triangular links below, the rigid rear axle was guided on semi-elliptical longitudinal leaf springs. All wheels had mechanically ( cable ) operated drum brakes .

literature

• Werner Oswald : All BMW automobiles 1928–1978 . Motorbuch Verlag, Stuttgart 1980, ISBN 3-87943-584-7 .

Web links

Commons : BMW 303  - Collection of Images, Videos and Audio Files

• Manual for the 1.2 Ltr / 30 HP 6 cylinder BMW. In: BMW history. BMW AG, July 1933, accessed on January 16, 2016 (manual with pictures, 95 pages). 
• Spare parts list and tables for the 1.2 liter / 30 PS BMW 6 cylinder car. In: BMW history. BMW AG, November 1933, accessed on January 16, 2016 (complete spare parts list with pictures, 110 pages). 
• Proper lubrication of the 1.2 liter BMW car. In: BMW history. BMW AG, 1933, accessed on January 16, 2016 (lubrication plan with pictures). 

Individual evidence

1. ↑ ^{a b c d e f g} Walter Drawer: Mobile Tradition live: The beginning of a long tradition. 70 years ago - BMW 303, the first six-cylinder car. In: BMW history. BMW AG, July 2003, pp. 8–11 , accessed on January 14, 2016 (Mobile Tradition live - Edition 02 / July 2003). 
2. ↑ Model BMW 303. In: BMW History. BMW AG, accessed on January 16, 2016 (dossier in the BMW Group archive with technical data). 
3. ↑ BMW M78 automobile engine 1.2 liters. In: BMW history. BMW AG, accessed on January 16, 2016 (dossier in the BMW Group archive with technical data). 
4. ↑ BMW 303 front axle and engine (chassis). In: BMW history. BMW AG, 1933, accessed on January 16, 2016 (photo in the BMW Group Archive). 

Timeline of the Dixi , BMW and EMW models from 1927 to 1955
Type	1920s				1930s										1940s										1950s
	6th	7th	8th	9	0	1	2	3	4th	5	6th	7th	8th	9	0	1	2	3	4th	5	6th	7th	8th	9	0	1	2	3	4th	5	6th
Small car		Dixi 3/15
				BMW 3/15			3/20
Lower middle class									309
								303	315
Middle class									319/329			320		321			...			321/2
											326						...			326/2				340		EMW 340
upper middle class														335
Roadster / Coupé / Convertible					BMW Wartburg				315/1 / 319/1			327					...			327						EMW 327
												328
Kübelwagen												325															EMW 325
Under the “Dixi” brand ; The Austin 7 compact car is built under license Produced under the brand "EMW" in the GDR by the Eisenacher Motoren Werk