BMW K1 Prototype
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Presentation Year: | 1938/39 |
Built: | single piece |
Class : | prototype |
Engine: | Gasoline : 3.5 litres |
Length: | 5000 mm |
Width: | 1700 mm |
Height: | 1500 mm |
Wheelbase: | 2984 mm |
The BMW K1 was an innovative test car the Bayerische Motoren Werke AG (BMW) from the year 1938/39 based on the BMW 335 .
History
As early as April 1, 1930, Kamm was appointed Professor of Automotive Engineering and Vehicle Engines at the Technical University of Stuttgart . In the same year he founded the non-profit research institute for automotive engineering and vehicle engines Stuttgart (FKFS) . This allowed him, in collaboration with industry research work outside the rigid university structures, especially with the companies based in southern Germany Daimler-Benz and BMW .It was a designed for high travel speeds and low consumption four-door sedan of the luxury class with comfortable furnishings and five full-size seats, pontoon body in a streamlined shape with comb-rear and 3.5-liter six-cylinder - inline engine.
The K1 was not developed in the BMW plant in Munich or in Eisenach (the former Dixi plant ) which was responsible for automobile production , but by Professor Wunibald Kamm at the Research Institute for Automotive Engineering and Vehicle Engines (FKFS) in Stuttgart . Special features of the K1 were its aerodynamically extremely favourable body as well as numerous technical innovations, which moved in some decades later in mass production.
Until the 1930s, the aerodynamics in vehicle construction - apart from a few record and racing cars - played no significant role. This changed in the 1930s with higher performance, better stability, and improved suspension technology . These have now allowed in passenger cars speeds over 100 kilometres per hour, from which the air resistance increasingly affects. Added to this was the rapid expansion of the Reich motorways in Germany . Therefore, in the late 1930s, there was a need for aerodynamically cheaper bodies in order to achieve higher speeds and a more favourable fuel consumption.
Rumpler and initially also Jaray chose superstructures that were relatively tall and narrow and where the air was directed past the side of the body. It turned out that this shape was not yet optimal, even if Jaray's designs already showed the aerodynamically favourable wing profile. Derived from this was the streamline "with cut off tail".The flow is largely guided over the gently sloping roof to the rear with laterally retracted, almost straight-capped tail. Wunibald Kamm had already explained this form in his lectures in 1933, but did not patent it and initially did not put it into practice. Koenig-Fachsenfeld also claimed to have discovered or (co) developed this aerodynamically form.
A first vehicle according to this principle put Emil Everling , a lecturer at the Technical University in Berlin-Charlottenburg completed in 1938, the E-car , built at full & Ruhrbeck in Berlin was followed in the same year by the BMW K1 of Kamm and BMW.From 1935 research on streamlined vehicles in the German Reich was subsidized by the state. The financial resources, which in particular flowed to the FKFS under its head comb, came from 1937 by the specially established for this purpose Reichsforschungsrat .
The first workable result of the work of the FKFS and Kamms in 1938/39 was the test car BMW K1 with its extremely wind-shaking bodywork and numerous technical innovations in the engine and chassis area. Three more sedans followed between 1939 and 1940, of which the models K2 and K3 on the chassis of the smaller Mercedes-Benz 170 V , while the BMW K4 built like the K1 on the "big" BMW 335 . Furthermore, Kamm provided the pattern for the later in racing, especially at the Mille Miglia successful BMW-328 - "racing sedan".
The BMW K1 was from the beginning as a test car, so not designed for mass production. In 1939 and 1940 extensive test drives took place, with temporarily mounted two large vertical airflow fins at the end of the roof. The advanced bodywork and technical innovations proved to be functional and highly efficient. However, the outer shape with its full-pontoon body, the unusual rear, the fully covered front and rear wheels and the temporarily mounted roof fins differed extremely from the then-production vehicles. The look came in the audience on some very harsh criticism. The K1 therefore remained a unique piece.
There was no predecessor in the strict sense for the K1 neither at BMW nor at Kamm or the FKFS . Similar to the idea was the test car of Paul Jaray based on a Dixi 6/24 hp type G 2. This was a narrow, high streamlined sedan with the nicknamed "whale", which was presented at a motor show in 1923 and the Was offered, but came across widespread rejection of the audience. The relation between the two models results from the fact that the automobile manufacturers Dixi 1928 BMW was acquired.
The BMW K1 name, unlike the intended for mass production BMW cars prewar from 1933 starting with the model 303 (1933-1934), no model name with three numbers and a "3" at the beginning. Like numerous later concept vehicles, he received a model designation with a letter and a single-digit number, similar to the later BMW E1 . Unlike the BMW M1 or the BMW Z1, however , the BMW K1 did not find its way into series production in this form.The BMW K1 is the only BMW car that shares its name with a BMW motorcycle model , the 1988 presented innovative sports touring BMW K1 with aerodynamically clad front wheel, full fairing including small luggage suitcases, a motor with regulated catalyst and one of the first anti-lock braking systems in the bicycle shop. The name derives in this case from the BMW K-series , a motorcycle series with longitudinal inline engines instead of the traditional two - cylinder boxer engines, Whether the motorcycle model is based on the name of the car model K1 in terms of the name , is not known, but in view of the sophisticated in both cases aerodynamics and the status as an innovation carrier to assume.
The most striking feature of the BMW K1 is its extremely unusual, then aerodynamically ideal body with its very spacious and comfortable interior.The low coefficient of drag was achieved by an aerodynamic full-wing wing-pontoon body, an unusually round and low-drawn front with flush mounted headlamps, full fairing front and rear wheel wells and a smooth, cased underbody. Another detail was the four-segment windshield with laterally rounded elements, as curved windscreens were still unusual. In addition, there were completely smooth body side panels, flush fitted front, rear and side windows and the absence of external door handles for the rear doors. Aerodynamically particularly important was the relatively long, gently sloping hatchback with gently retracted side panels and relatively straight cut rear end.
For a BMW untypical the K1 wore not the otherwise usual since 1933 BMW kidney , but an oval, standing, in the flowing body lines integrated and clad with longitudinal struts cooling air opening. Typical of BMW pre-war models, however, was the arrangement of the four doors, as they had already proven on the Model 326 : the front doors were struck behind (so-called " suicidal doors "), the rear doors, however, front. The doors were thus in opposite directions, the door hinges each attached to the B-pillar .The two large vertical tail fins, which were temporarily mounted on the roof of the K1 , should conduct the air flow above the roof and behind the vehicle cheaper; In practice, the advantages of the fins proved to be too low, since they deteriorated both the crosswind stability and the straight-line stability .
The design was aerodynamically extremely consistent and designed without regard to the contemporary taste, which is why outside was dispensed with any chrome elements and other ornaments, as well as on bumpers that could have avoided damage to the body in everyday life.The body had been built by the company Walter Vetter body and vehicle in Fellbach near Stuttgart to the plans Kamms and FKFS . known were the still existing companies at that time mainly by the production of car bodies based on Mercedes-Benz -Fahrgestellen, but also bus superstructures in streamlined form for a license of Paul Jaray.
The interior dimensions of the K1 were due to the wide full-pontoon body without flared fenders and running boards, but with hatchback extremely generous. Contributing to this were the - despite the goal of the best possible aerodynamics - relatively steep front or side windows. In the rear was a large, accessible from the outside trunk. The interior was complex and comfortable to meet the demand of a long-distance touring sedan. Because of the respect to the initial model BMW 335 bouffant body and the sumptuous interiors was the weight of the K1 with about 1,500 kilograms relatively high and well above the standard 335 . 335 pre-production chassis that BMW provided to FKFS under the direction of Kamm 1938. Constructively, it was derived from the model 326 , but in comparison to this reinforced and extended by 234 millimetres to 2984 millimetres. The K1 thus had also a Tiefbett- box frame with a front suspension from upper wishbones and a transverse spring below and a track width of 1306 millimetres. At the back he had a solid axle with two longitudinal spring bars and a gauge of 1404 millimetres. This was considered more comfortable, but less sporty than the rigid axle with semi-elliptical leaf springs of the 327 and 328 , which better suited the claim of the K1 as a comfortable travel sedan. It had rack- and- pinion steering as well as hydraulically-operated internal drum brakes on all four wheels with cable-operated handbrake on the rear wheels.
Innovative feature of the BMW K1 was a tire pressure control system , which made it possible to increase the tire pressure from the dashboard while driving and thereby reduce the rolling resistance of the tires ; As a result, fuel consumption was significantly reduced on the well-developed new highways, especially at higher speeds.
Engine and transmission
The BMW K1 also received the newly designed engine of 335 , so the water-cooled six-cylinder four-stroke -Reihenmotor with 3485 cc capacity and long excursion ( bore 82 millimetres Stroke 110 mm). It had - just like the smaller 2.0-liter version - a crankshaft mounted only four times and a side camshaft with overhead valves ( OHV valve control ), the bumpers and rocker arms were pressed. In contrast to the 2.0-liter version, the camshaft of the 3.5-liter version was not driven by duplex chain , but by Novotex spur gears. At a compression ratio of 1: 5.8 made with the two double register carburettor’s equipped engine 66 kW (90 hp) at 3500 min -1 . The power transmission was done in the usual way via a single-disc dry clutch on a manual four-speed transmission with rear-wheel drive .
Innovative feature special overdrive enabled the engine speed to be reduced at higher speeds, further reducing fuel consumption. In test runs, the obtained FKFS and BMW for that time outstanding consumption of 7.6 Liters per 100 kilometres at a constant 100 km / h and 10 litres per 100 kilometres at an average of 120 km / h, and 12 Liters per 100 kilometres at a constant 140 km / h. With the same power of 66 kW (90 hp) reached the BMW K1a top speed of then and now - especially considering the size of the vehicle and the respectable 183 km / h compared to 145 km / h of the series BMW 335 .
For BMW , the experience of testing the K1 was so helpful that it helped Kamm in the following year in the development of the slightly more conservative BMW K4 . Furthermore, the experience of BMW with the K1 and K4flowed into the development of various planned production vehicles: the BMW 332 , intended for 1940 successor to the successful model BMW 326 , and the BMW 337 , planned for 1941 luxury and upper-class model above of the BMW 335 .
