Onthe short list of the most glamorous cars ever built is the Mercedes-Benz 500K Special Roadster. Its flowing lines and elegant persona attracted celebrities and royalty. The example shown here, on display at the National Automobile Museum in Reno, Nevada, was linked with both of these segments of society – albeit involving some questionable, perhaps even shady, characters.
First, some background on the 500K design and some of the car’s notable clientele. Then we’ll relate how this particular one ended up in the hands of a purported Russian princess and the son of Sir Arthur Conan Doyle, creator of Sherlock Holmes.
Marvelous chassis and engine
Designated the W29 by the factory, the 500K improved markedly on its predecessor, the somewhat sedate 380 model. The two shared the same smooth suspension, constructed of independent dual-wishbone fronts with ball joints, and double-jointed, swing-axle rear end, along with then-revolutionary shock absorbers. The 500K also featured two transverse-mounted coils that served as “compensators” to minimize body roll. The nomenclature of these two models referred to the straight-eight 3820cc M22 engine of the 380 and the greatly increased 5018cc M24 straight-eight engine of the 500K.
When naturally aspirated, fed by a single twin choke carburetor, the M24 delivered 100 horsepower or so at low speeds. But as indicated by the “K” designation, a Roots-type Kompressor supercharger mounted ahead of the carburetor could be activated by mashing the throttle, boosting the output to 160 horsepower. As was the usual practice at the time for Mercedes-Benz, the supercharger is mechanically connected to the foot throttle, and engaged through a multiple-disc clutch running in oil.
We have spoken with a couple of the expert restorers who have driven the 500K Special Roadster seen here and now on display at the National Automobile Museum. They note that at 4,500 pounds, the hefty 500K offered somewhat “truck-like” ride and handling characteristics, as was typical of the era. However, acceleration is delightful and instantaneous. That's impressive considering the massive size of this automobile. Activating the supercharger results in a shrill whine, like a light siren, and performance is both swift and smooth. When the driver lifts off the throttle, another multi-disc clutch disengages the supercharger, abruptly cutting the power and noise. With this much power on tap, the 500k is capable of exceeding the 100 mph mark, just the thing for high-speed cruising on the then new Autobahn.
The M24 engine was backed by either a four- or five-speed manual transmission with synchromesh for the top three gears. Brakes were hydraulic and vacuum-assisted as well. All of these mechanical elements were state of the art technology back in the day, in keeping with the car’s performance potential.
Dependability was another hallmark of the car. One Swiss owner reported that he could comfortably drive from Zurich to Berlin, a distance of some 560 miles, in a single day at an average speed of 55 mph or so. That might seem routine by today’s standards, but was a considerable achievement back then, especially on the rough roads of the era.
A car of its era
Production of the 500K began in 1932, and three models debuted at the 1934 Berlin auto show: A Cabriolet, a fast-back Coupe (the Autobahn Kurier), and the exquisite Special Roadster (the example shown here). Later additions to the exotic, limited production range were a standard Roadster, and Cabriolets in two- and four-passenger configurations.
The 500K was offered for only two years, between 1934 and 1936, when it was succeeded by the somewhat lighter 540K, made from 1936 to 1939. Mercedes reduced the car's weight by using oval tubing rather than hefty girders for the frame. As indicated by the name change, the engine was enlarged to 5401cc, with an increase in power to 180 horsepower. Otherwise, these two models were fairly similar, except that the 540K was a bit more curvaceous. Even though chassis production ended in 1939, some bodies were mounted later on, as 540Ks were still being delivered to special customers as late as 1941 and 1942. Combined production was 342 units for the 500K, and 419 of the 540K, with only 58 roadsters built in total.
As noted in the National Automobile Museum’s reference material, the 500K was shown at the leading European International Automobile Exhibitions in Brussels, Geneva and London. The engineering and mechanicals of the 500K Special Roadster were typical of Mercedes-Benz – solid, sturdy, dependable, and put together with superb craftsmanship at every step from casting and machining to assembly. The handsome and luxuriously appointed body of the Special Roadster was crafted by the Sindelfingen Coachworks subsidiary of Mercedes-Benz. By any measure, this is one of the most beautiful automobiles ever built. The price when new was $10,780 – an imposing sum considering that the average cost of a new car back then was $760! But this example would eventually change hands for far less.
These big, luxurious Mercedes models saw little action at competition events, but were well suited to the 1,240-mile Deutschland Fahrt of 1934. This rally had no speed limits, favoring the 500K’s top-end capabilities. Only 74 Mercedes competed in a field of 600 cars, with most being smaller 170s, but 500Ks won two gold medals.
Glamour and intrigue
In keeping with their rarity and prestige, these glamorous Mercedes-Benz models seem to have a special magnetic allure all their own. They are prized by both racers and collectors, along with various celebrities such as Jack L. Warner of the Warner Brothers film studios. Also, Formula One impresario Bernie Ecclestone's 500K Special Cabriolet fetched nearly $1.45 million at auction in 2007.
This 500K Special Roadster was purchased at the London Automotive Exhibition by Princess Nina Mdivani, wife of Denis P. S. Conan Doyle. They drove it throughout Europe on their honeymoon, starting where they were married at St. Donat’s Castle in Wales, owned at the time by William Randolph Hearst.
While the name Sherlock Holmes is widely recognized, the Mdivani family is not so famous, except for a time in the 1920s. The princess’ three brothers developed a reputation for marrying – and mistreating – American heiresses, opera stars, and a fading silent-film star Mae Murry, known in the celebrity press as the "girl with the bee-stung lips."
While the Mdivani lotharios boasted of being Russian royalty, some wags smirked that this title was about as valid as claiming to be a Kentucky Colonel. Like some current celebrities, they were known for being famous and not much else, apart from their smoldering looks. But their aristocratic image enchanted social climbers in the booming Los Angeles film community.
Princess Mdivani was somewhat more discreet than her scheming brothers and her dissolute sister Roussy, who was once referred to as a “stray cat,” but she was not without some gold-digging foibles of her own. Her first marriage was to successful attorney Charles Huberich, who was 24 years her senior. Funded by him, she led a life of leisure, globe-trotting and sponsoring various artists of the day. She divorced her attorney husband just after the death of her brother Serge in a horse-riding accident. Following the pattern of her status-seeking family, she soon married Denis Conan Doyle. This marriage appeared to be a love match, even as it was a step up in social status. She eventually inherited a third of the Doyle estate after he died in 1955, along with the same portion of rights to the Sherlock Holmes legacy.
In her declining years she was forced to sell off her car and the jewelry given to her by confidante and socialite Barbara Hutton. But one elegant piece remained with Nina until her passing; a famous jade necklace ultimately worth $27.44 million, which was found hidden under her deathbed.
Tracing the provenance of a legend
Mdivani's 500K changed hands (and color) a few times. Originally the car was pale blue, then painted ivory when owned by Alan McCarroll, who purchased it from the Mercedes plant in 1953 for only $300. McCarroll later moved to Mexico City but found it difficult to maintain the car there; he sold it for $10,000 to Arkansas Governor Winthrop Rockefeller, who had silver paint applied. Another source, however, who once maintained the Harrah car collection, has records showing that J.B. Nethercutt, co-founder of Merle Norman Cosmetics, once owned the car until the early 1960s. Rockefeller founded the Museum of Automobiles, where the car was housed until 1975 when the entire collection of some 70 cars was sold to Harrah’s Automobile Collection.
"The 1936 Mercedes 500K with the Sindelfingen Special Roadster body represents all things that make up the classic car," says Jay Hubbard, Automotive Collections Manager at the National Automobile Museum. "This car was built for the Classes, not the Masses. Its styling, sweeping fenders and long hood are the archetype of 1930s automobiles, and its massive straight-eight supercharged engine and independent rear suspension are at the forefront of prewar technology."
Today, the National Automobile Museum displays this 500K Special Roadster among an illustrious collection of more than 200 cars dating back to 1892. The majority of the Museum’s automobiles were formerly owned by the late, world-famous gaming pioneer and collector Bill Harrah. The mission of the Museum is to collect and preserve these unique automobiles for future generations, and to convey their impact on American society. While the 500K was once an emblem of wealth and prestige, it now provides a superb window into a bygone age, and serves as an extraordinary example of innovative automotive engineering from Mercedes-Benz.
