BMW 309

BMW
309
Production period:	1934-1936
Class :	Lower middle class
Body versions :	Touring car , limousine , convertible sedan , convertible
Engines:	Otto engines : ; 0.85 liters (16 kW)
Length:	3750 mm
Width:	1440 mm
Height:	1550 mm
Wheelbase :	2400 mm
Empty weight :	750 kg
Previous model	BMW 3/20 PS

The BMW 309 was a small passenger car that was built by BMW in Eisenach between 1934 and 1936 as the successor to the 3/20 PS .

history

In order not to lose some of the customers after the end of production of the BMW 3/20 , BMW brought the 309 onto the market in early 1934 , which combined the chassis and body of the 303 with the cheaper drive of the 3/20 . In order to adapt the engine output to the higher car weight, the displacement was increased to just under 850 cm³, whereby the output rose to 22 HP (16 kW).

The cars were produced in 1934 as a chassis without a body (2550 RM ), sedan (3050 RM), convertible sedan (3250 RM), touring car (3550 RM), convertible with 4 seats (3850 RM) and convertible with 2 seats (4050 RM) delivered, each with 2 doors. In 1936 the four-cylinder model was discontinued without replacement - the next four-cylinder from BMW did not come onto the market until 1962 in the “New Class” . 6000 copies of the type 309 were built.

technology

engine

The in-line four-cylinder engine of the predecessor 3/20 was essentially adopted, but the displacement increased to 845 cm³ by enlarging the cylinder bore - from 56 mm to 58 mm with a still 80 mm stroke. The output increased to 22 HP (16 kW), which was delivered at 3500 min ⁻¹ . The engine was referred to in all of BMW's publications as the “BMW four-cylinder 0.9 L / 22 hp with a“ floating engine ”. The term "floating motor" referred to the fact that the motor and the locked gearbox were elastically suspended at two points. BMW had acquired a license for this from Chrysler.

The elastic suspension was made possible, on the one hand, by the generous amount of space that the relatively compact four-cylinder had in the engine compartment of the six-cylinder engine, on the other hand, it was necessary to dampen the vibrations of the four-cylinder with only two crankshaft bearings and without counterweights on the crankshaft cheeks Keep the chassis away.

BMW itself clearly identified the problem and its solution:

“Only technicians and practical drivers know exactly how to name the sore point of the four-cylinder: It runs hard and causes vibrations. The time that pushed the four-cylinder aside for this reason is over. Today, with really advanced four-cylinder engines, the entire engine gearbox block is suspended in rubber so that the machine system does not need to force its nature; on the contrary, it may vibrate around a center of gravity as much as nature requires - but that this vibration cannot reach the chassis, On the contrary, it is mainly transformed into useful motor work by the spring effect of the sensible rubber suspension. (BMW has the license for the original Chrysler 2-point suspension!) "

- BMW sheets 19/1934

BMW also marketed this construction several times as “DRP. registered ”, or“ DRP a ”- ie registered as a patent in the German Reich.

Like the six-cylinder model, the 309 received a four-speed gearbox with center shift and rear-wheel drive; the third and fourth gears were synchronized. The vehicles reached a top speed of 80 km / h.

landing gear

With the low frame, the construction of the 309 corresponded to that of the six-cylinder model 303 presented last year . The front wheels were independently suspended from a transverse leaf spring (above) and wishbones (below), the rigid rear axle from semi-elliptical longitudinal leaf springs screwed to the axle bracket from below . All four wheels were fitted with drum brakes that were operated with a cable.

literature

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

Web links

Commons : BMW 309 - Collection of Images, Videos and Audio Files

Model BMW 309. In: BMW History. BMW AG, accessed on January 17, 2016 (dossier in the BMW Group archive with technical data).
BMW M68 automobile engine 0.85 liters. In: BMW history. BMW AG, accessed on January 17, 2016 (dossier in the BMW Group archive with technical data).
Manual for the 22 HP BMW 4-cylinder car. In: BMW history. BMW AG, March 1934, accessed on January 17, 2016 (manual with pictures, 90 pages).
Spare parts list and tables for the BMW 4 cylinder car type 309. In: BMW history. BMW AG, December 1934, accessed on January 17, 2016 (complete spare parts list with pictures, 129 pages).

Individual evidence

↑ The new four-cylinder BMW 309. In: BMW History. BMW AG, February 1934, accessed on January 17, 2016 .
↑ Model BMW 309. In: BMW History. BMW AG, accessed on January 17, 2016 (dossier in the BMW Group archive with technical data).
↑ Price list No. 15 for BMW 309, 303, 315/1. In: BMW history. BMW AG, March 1934, accessed on January 17, 2016 (document in the BMW Group archive).
↑ BMW 309 engine. In: BMW history. BMW AG, 1934, accessed on January 24, 2016 (photo in the BMW Group archive): "Partial view of the chassis with colored engine and transmission"
↑ ^a ^b BMW sheets 19. In: BMW history. BMW AG, March 1934, pp. 11-13 , accessed on January 24, 2016 (document in the BMW Group archive): "BMW has the license for the original Chrysler 2-point suspension!"
↑ ^a ^b 22 HP four-cylinder with floating engine (DRP. Registered) and 34 HP six-cylinder, two high-quality utility cars. Efficient, reliable and economical! In: BMW history. BMW AG, February 1935, accessed on January 24, 2016 (document in the BMW Group archive).
↑ BMW 309, 315; "The new BMW models are the pinnacle of lightweight vehicle construction". In: BMW history. BMW AG, May 1934, accessed on January 24, 2016 (document in the BMW Group archive).

Timeline of the Dixi , BMW and EMW models from 1927 to 1955
Type	1920s				1930s										1940s										1950s
Type	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
Small car				BMW 3/15			3/20
Lower middle class									309
Lower middle class								303	315
Middle class									319/329			320		321			...			321/2
Middle class											326						...			326/2				340		EMW 340
upper middle class														335
Roadster / Coupé / Convertible					BMW Wartburg				315/1 / 319/1			327					...			327						EMW 327
Roadster / Coupé / Convertible												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

[BMW_3609095_1932-1] The new four-cylinder BMW 309. In: BMW History. BMW AG, February 1934, accessed on January 17, 2016 .

[BMW_3829948_Dossier-2] Model BMW 309. In: BMW History. BMW AG, accessed on January 17, 2016 (dossier in the BMW Group archive with technical data).

[BMW_3077409_Preisliste_15-3] Price list No. 15 for BMW 309, 303, 315/1. In: BMW history. BMW AG, March 1934, accessed on January 17, 2016 (document in the BMW Group archive).

[BMW_688555-4] BMW 309 engine. In: BMW history. BMW AG, 1934, accessed on January 24, 2016 (photo in the BMW Group archive): "Partial view of the chassis with colored engine and transmission"

[BMW_3689225_BMW_Blätter_19-5] BMW sheets 19. In: BMW history. BMW AG, March 1934, pp. 11-13 , accessed on January 24, 2016 (document in the BMW Group archive): "BMW has the license for the original Chrysler 2-point suspension!"

[BMW_3080643-6] 22 HP four-cylinder with floating engine (DRP. Registered) and 34 HP six-cylinder, two high-quality utility cars. Efficient, reliable and economical! In: BMW history. BMW AG, February 1935, accessed on January 24, 2016 (document in the BMW Group archive).

[BMW_3080559-7] BMW 309, 315; "The new BMW models are the pinnacle of lightweight vehicle construction". In: BMW history. BMW AG, May 1934, accessed on January 24, 2016 (document in the BMW Group archive).