Mercedes Benz W29 540K M24 II Coupe by Hebmuller
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Car producer : |
Mercedes Benz |
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Model: |
W29 540K M24 II Coupe by Hebmuller |
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Year: |
1936-1938 |
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Type: |
Coupe |
The Mercedes 500K (type W29) is a grand touring car built by Mercedes-Benz between 1934 and 1936. First exhibited at the 1934 Berlin Motor Show, it carried the factory designation W29. Distinguished from the 500 sedan by the "K" for Kompressor (German for supercharger) only fitted to these performance cars, it succeeded the Mercedes-Benz 380 introduced just the previous year. It offered both a larger, more powerful engine and more opulent coachwork to meet customers' demands for greater luxury and performance.
The 500K used the same independent suspension as had been introduced on the 380, with a double wishbone front axle, double-joint swing axle at the rear, and separate wheel location, coil springs and damping, a world first. Consequently it was a more comfortable and better handling car than Mercedes' previous S/SS/SSK generation of roadsters from the 1920s, and offered greater appeal to buyers, particularly the growing number of well-heeled female drivers of the time.
Together with the succeeding 540 K, the magnificent Mercedes-Benz 500 K was arguably the most noteworthy production model offered by the Stuttgart firm during the 1930s. Introduced at the Berlin Auto Show, a mere 13 months after the 380's arrival, the 500 K was powered by a 5,018cc overhead-valve straight-eight engine that featured the company's famous Roots-type supercharger system in which pressing the accelerator pedal to the end of its travel would simultaneously engage the compressor and close off the alternative atmospheric intake to the carburetor. This system had been thoroughly proven on the preceding series of Dr. Porsche-conceived S-Type cars, and in effect the 500/540 K was the last supercharged production Mercedes until relatively recent times. The 380 continued in production but by the end of 1934 had gone, leaving the 500 K unchallenged at the top of the Mercedes-Benz range.
Generously braced, the 500 K's box-section chassis boasted independent suspension all round: by wishbones and coil springs at the front and swing axles at the rear, with damping by hydraulic lever-type shock absorbers. Horizontal camber compensating springs were a later addition to the swing axles, further refining wheel control. Standard equipment included two spare wheels, safety glass, electric windscreen wipers, centralized lubrication, and a central fog light.
Beneath its impressing bonnet, the 500 K's eight-cylinder pushrod engine developed 100bhp un-supercharged or 160bhp at 3,400rpm with the compressor engaged. Cast as one in steel, the combined crankcase/cylinder block was topped by a cast-iron head, while the oil supply was contained within an aluminum sump. The gearbox was a four-speeder with direct (1:1) 3rd gear and overdrive top ratio, the latter engaged via a pre-selector mechanism.
The manufacturing record of the 500 K reveals its exclusive nature: 105 being produced in 1934, 190 in 1935 and 59 in 1936 making a total of 354 cars, of which it is estimated that only 29 were completed with Roadster or Spezial Roadster coachwork. In recent years, the rarity, style and performance of these big supercharged Mercedes have made them one of the most sought-after of all classic cars on the few occasions they have come on the open market.
The straight-8 cylinder engine of the 500K was increased to 5,401 cubic centimeters (329.6 cu in), which aspirated by twin pressurized updraft carburetors, developed a natural 115hp (86 kW). However, there was an attached Roots supercharger which could either be engaged manually for short periods, or automatically when the accelerator was pushed fully to the floor. This increased power to 180hp (130 kW), creating a top speed of 170 kilometers per hour (110 mph).
Few 540 Ks were more beautiful than the second-generation Cabriolet A, of which only thirty-two examples were built. This design offered fuller front fenders that elegantly flowed rearward towards the rounded tail, which housed dual spare tires. The elegant styling and great power of the supercharged engine and its external exhausts were further enhanced via a feature identified colloquially as the “set-back radiator.” Referred to by the factory as Fahrgestell mit zurückgesetztem Motor, “chassis with setback motor,” in fact the radiator and entire drivetrain were positioned 185 mm farther back on the chassis than standard. This gave the car a completely different air, with a longer, more aggressive front end, which is most closely associated with the fabled Spezialroadster.
As a complete package, it ranks among the most elegant and graceful German coachwork of its era and today is among the most highly sought-after by enthusiasts. The survivors are prized, and the few truly unique examples that have been missing to the larger collecting world for half a century seldom if ever become available.
Although the 500K/540 K chassis attracted the attention of many of the better quality bespoke coachbuilders of the day, the company's own Sindelfingen coachwork left little room for improvement. With a lengthy wheelbase of almost 3.3 meters, and a tall engine, the 500 K must have been a challenge to body in sporting style, yet few would deny that with the Roadster version, as seen here, master stylist Hermann Ahrens and the craftsmen at Sindelfingen succeeded brilliantly.
The Roadster was offered in two versions, 1st Series that was characterized by the absence of windup windows, a fully folding convertible hood, and twin spare wheels mounted on the short, tapered tail, which featured chromed, stalk-mounted tail lights.
To meet individual wishes of customers, three chassis variants were available as for the 500K: two long versions with a 3,290 mm (130 in) wheelbase, differing in terms of powertrain and bodywork layout; and a short version with 2,980 mm (117 in). The long variant, termed the normal chassis with the radiator directly above the front axle, served as the backbone for the four-seater cabriolets 'B' (with four side windows) and 'C' (with two side windows), and for touring cars and sedans. However, a small number received 'Tourenwagen' or sports Touring coachwork. This design, would have cost its first owner some 22,000 Reichsmarks and owes more to the earlier Sindelfingen bodies that can be found on six-cylinder supercharged cars, being more lithe, vintage, open and sporting, than the better known series of Cabriolets. It is a style that emulates the British touring cars of the same era more than those in Germany, perhaps not surprisingly because the UK was such a strong market for them. Of the 500K series, just 16 were delivered as Tourenwagens. The shorter chassis was for the two-seater cabriolet 'A,' set up on a chassis on which radiator, engine, cockpit and all rearward modules were moved 185 mm (7.3 in) back from the front axle.
On top of the normal and roadster cars, 12 special cars were developed on an extended chassis length with a 3,880 mm (153 in) wheelbase. All of these cars were developed for the Nazi hierarchy, as six seater convertible saloons. To allow for armor plate, these cars had developed De Dion rear suspension. Due to their higher weight, their maximum speed was 140 km/h (87 mph).The straight-8 cylinder engine of the 500K was increased to 5,401 cubic centimeters (329.6 cu in), which aspirated by twin pressurized updraft carburetors, developed a natural 115hp (86 kW). However, there was an attached Roots supercharger which could either be engaged manually for short periods, or automatically when the accelerator was pushed fully to the floor. This increased power to 180hp (130 kW), creating a top speed of 170 kilometers per hour (110 mph).
Power was sent to the rear wheels through a four-speed or optional five speed manual gearbox that featured synchromesh on the top three gears. Vacuum-assisted hydraulic brakes kept the car under the driver's control.
The 540K had the same chassis layout at the 500K, but was significantly lightened by replacing the girder-like frame of the 500K with oval-section tubes - an influence of the Silver Arrows racing campaign.
The Sindelfingen factory employed 1,500 people to create the 540K, and allowed a great deal of owner customization, meaning only 70 chassis were ever bodied by independent builders. Owners included Jack Warner of Warner Brothers film studios.
Late in 1938, a revised 540 K made its appearance, with oval-section chassis tubes instead of channel frame members, while the adoption of sodium-cooled valves followed the company's highly successful racing practice.
With the outbreak of World War II in 1939, the proposed further boring-out of the engine to 5,800 cubic centimeters (5.8 l) for a 580K was aborted, probably after only one such car was made. Chassis production ceased in 1940, with the final 2 being completed that year, and earlier chassis were still being bodied at a steady rate during 1940, with smaller numbers being completed in the 1941–1943 period. Regular replacement bodies were ordered in 1944 for a few cars.
After the assassination attempt on Reinhard Heydrich in Prague at the end of May 1942, the Reich Chancellery would only use armoured cars for ministers and leaders of friendly powers. Beside 20 large Mercedes-Benz 770s, in 1942 they ordered an additional 20 540Ks developed as two door armoured saloons. These were delivered during 1942 and 1943. A further order for 17 armored saloons was placed in late 1943, and these were delivered in April 1944. One of these cars was given as a gift from Adolf Hitler to Ante Pavelić, leader of the Independent State of Croatia. After the war this car was captured and used first by Ivan Krajacic, and then by Josip Broz Tito.
In 1936, Mercedes-Benz launched the 540K special, designated 540Ks. Based on the shorter 2,980 mm (117 in) wheelbase chassis, its body was carefully crafted. Its price tag of 28,000 Reich marks, some RM6,000 above the price of standard models, meant only 32 were ever built.
The manufacturing record of the 540 K reveals its exclusive nature: 97 being produced in 1936, 145 in 1937, 95 in 1938 and 69 in 1939 before the war ended series production (though three more were built up to July 1942).
