
It was the year 1952, and Mercedes had just won a series of prominent international racing events with their W194 racecar. And that's all it was, a racecar, an experiment; they had no plans to put the car into production. But thankfully fate intervened.
A New York City-based automobile importer named Max Hoffman had recently signed a contract to import Mercedes' cars to the U.S.A. As a former racecar driver himself, Hoffman's attention was then captured by the W194's victories making the news rounds. I'm guessing Hoffman was eager for a chance to drive the car himself, but the fact is that he knew cars as well as he knew customers, and he felt strongly that a roadgoing version of the W194 was something his well-heeled clientele would line up to buy.
He lobbied Mercedes to build one, and while they were initially resistant, Hoffman employed some clever tactics to get them to agree. (That story, and Hoffman's subsequent influence on auto design history, is fascinating enough that it will get its own entry later.) Based on Hoffman's prompting Mercedes greenlit the W198, a road-ready version of the W194.
Now we turn to why the car has gullwing doors in the first place. As we learned in the entry on its W194 antecedent, the car was constructed using an unusual system of alloy tubes assembled into interconnected triangles. This gave the frame the necessary rigidity at an extremely low weight. But in order to achieve enough rigidity in the areas flanking the passenger compartment, the framing had to extend upwards much higher than your average car door's sill. This precluded the possibility of designing a car door that would allow sufficient room for the driver and passenger's ingress and egress.
In the roofless versions of the W194 racecar, this was no problem: The driver could climb in and out.

For the enclosed W194 versions, like the one below that took second place in Italy's 1952 Mille Miglia endurance race, Mercedes engineers had to work out a point of access.

Mercedes chief engineer Rudolf Uhlenhaut and his team looked at the problem: creating a conventional door above the high sill line was not an option—the resultant aperture would be too small for any human, even a racecar driver, to be expected to clamber through. They clearly needed to enlarge the aperture, but there was no way to go down, not without compromising the frame. The only way to go was up, incorporating a chunk of roof into the door. That would make a hole large enough for a driver and co-driver to get into. But how the heck would you hinge such a thing?

They then decided to hinge the thing at the top. I cannot stress enough how radical a design twist this was in those days, when every other car door opened on a horizontal plane.

Sticklers of auto design history will point out that fourteen years earlier, in 1939, Jean Bugatti had quietly designed papillon ("butterfly") doors that opened at an upward angle for the Bugatti Type 64; I'd point out that the design was never realized in mass production, and that fourteen years earlier much of the world (and particularly Germany) was embroiled in a World War, and Uhlenhaut and his team were decidedly not ogling Bugatti's design on Facebook.
Jean Bugatti, by the way, tragically died at age 30 in 1939, the same year he designed the papillon doors, while testing a race-winning prototype. A freaking drunken bicyclist, of all things, wandered onto the track during Jean's run; he swerved to avoid him, wrapped the prototype around a tree, and died.
The end result is that Uhlenhaut and his team are widely credited with the invention of the gullwing door, and that elegant design solution (coupled with the car's legendary fuel-injected performance) has rendered the 300SL Gullwing an automotive icon. Clambering in and out of the vehicle is still an awkward affair, mitigated somewhat by a steering wheel designed to tilt downwards to admit your legs; but goddamn is it cool, and the upshot is you'll never ding that door into the car next to you.

Just six months after Hoffman's last, successful plea, Mercedes had a floor model ready for prime time. They typically displayed their new models at the auto show in Frankfurt, but as per Hoffman's assurances that he could sell the 300SL to Americans, they took the unusual step of unveiling the car at the 1954 New York Auto Show instead.

The response was tremendous. According to the automotive fan site Serious Wheels, members of the press "were falling over themselves to lavish praise on the 300 SL:"
"Autosport" reported that: "The exterior form of the 300 SL is quite wonderful and its performance almost unbelievable. The construction of the car and its production quality are first class and the whole concept represents an uncompromising realization of all the new ideas."After its initial test, "Road & Track" wrote: "We are looking at a car where a comfortable interior is complemented by remarkably impressive handling characteristics, quite incredible roadholding, light and precise steering, and performance levels which are up there with—and even an improvement on—the best cars the automotive industry has to offer. There is only one thing left to say: the sports car of the future has become a reality."
And "auto, motor und sport" noted: "The Mercedes 300 SL is the most refined and at the same time the most inspirational sports car of our era—an automotive dream."
For Mercedes to go from a luxury car to a prize-winning racecar to an influential Manhattan showroom, all in the span of less than five years, was a long road. But after the reception at the New York Auto Show, Mercedes turned on the production line.

A persistent Hoffman received his first shipment of 300SL Gullwings in 1955, handing some 1,100 sets of keys over to eager buyers for the next three years.
The American market was responsible for the lion's share of 300SL Gullwings. Before doing research and learning about Hoffman, I'd assumed the car had been designed for Germany's Autobahn; but Mercedes only produced 300 units for domestic sale. Hoffman's persistence and Uhlenhaut's brilliant design and engineering skills had yielded a highly-sought-after triumph of design, one that looks just as good today as it did in 1954.

Up Next: The 300SL Gullwing Today
The Origin of the Mercedes 300SL Gullwing
» Intro: Why a Car Collector with a One-Car Collection Is the Richest of Them All
» Part 1: The Type 300
» Part 2: The W194
» Part 3: Mercedes Gets Convinced and Heads to New York
» Part 4: The Gullwing Today
Comments
Can you explain more about why it was necessary to place the doors in the manner they did? It seems more a stylistic choice to me: it wouldn't be significantly harder to place the exact same door in a slightly different hinge position, and the chassis would end up cut the same way either way so the hinge direction shouldn't affect frame strength. It's still great, but was it really functional?
This is a great series. Always puzzled how ideas like this get caught in eddies and languish. Surely any technical/mechanical issues that hindered the use of the design have been licked.
Just an amazing looking piece of work, without even factoring in the advanced ideas.
To will's question, isn't the door placement limited by the tubular frame members which were designed for the race car?
Juan Manuel Fangio and his team mate Stirling Moss drove similar cars at Le Mans in 1955. Because of his race conquests, Mercedes Benz awarded Fangio a beautiful blue gull wing. Both cars, the gull wing and the Le Mans version are on display at Fangio Museum in Balcarce city, Argentina:
http://auto.idoneos.com/index.php/Museo_Fangio/Fotos_Museo_01
Truly excellent article Hipstomp. I look forward to that anecdote about Hoffman's persuasion...
@Paul, I think Will is suggesting the same door shape, but hinged like a regular car door - which would end up being something like the Ford GT40 I guess?
Could you say something about the crash in 1955 that killed ~81 people and made Mercedes withdraw their factory sponsored racing program. Also please address the '55 300slr (think 722 car and Sterling Moss). I'd guess it was an transitional body; open top, flip up half door for the driver, and an interesting transmission location.
Keep up the good work