Stuff: Convertible history

[svgallery name="1971_MB_Cab"]

Wind-in-your-hair motoring through the ages

A recent drive in some older 'Benz convertibles highlight the evolution of the open-air car

By John LeBlanc MALLORCA, Spain - Completely unlike what's available in new-car showrooms these days, at the dawn of the automobile age more than a century ago, virtually all cars were convertibles. The main reason was cost and weight. The features car buyers take for granted today in even the least expensive set of wheels – roof, glass windows, proper weatherproofing – were either too expensive or too heavy It would take until 1910 before luxury brand Cadillac offered the first fully enclosed car. As you can imagine, protection from the elements caught on quickly with early-20th-century car buyers. By the 1920s, nine in 10 cars sold were closed-body models; the convertible was relegated to top-end models or low-volume sports cars. It would take the post-World War II economic boom for convertibles to come back in style. By the mid-1960s, almost every American car model offered an open-air version, from the smallest compacts to the largest land yachts. Most, like the 1971 Mercedes-Benz 220 SE pictured above, conjured up an elegant and carefree lifestyle. However, car buyers' new-found love for air conditioning, along with proposed U.S. government rollover safety legislation, almost killed the convertible for good in North America. By 1976, the only American-made convertible for sale was the Cadillac Eldorado. It would take six years before Chrysler revived the American convertible with its K-Car-based LeBaron. The convertible never returned to the high-watermark of the mid-1960s, but most automakers now have at least one open-air car in their lineup. And since the days of the 1976 Eldorado, one reason open-air cars have remained popular is the progress automakers have made in making them as comfortable and safe as hardtop counterparts. Although the Eldorado would have been one of the most luxurious cars you could buy when new 34 years ago, it was sorely lacking in comfort and safety compared to most of today's open-air cars. Most convertibles now offer heated seats to supplement the climate-control system on cooler top-down days. Some, including Audi, Mercedes-Benz and Infiniti, offer additional heating ducts in seat head-restraints to blow warm air around the neck of passengers. And for summer days when the sun is blazing, the top is down and the air conditioning can't handle the job, you'll find cooled seats available on option lists. Ironically, the biggest beef for some convertible buyers is the amount of air intrusion, or buffeting, that occurs when the top is down. So much for that "wind-in-your-hair" feeling. To try and conquer this, some 2+2 convertibles have offered a draft stop that can be erected behind the front seats to stop air from backwashing onto the head-restraints of front-seat occupants. The new 2011 Mercedes-Benz E Class Cabriolet that I drove tries to go one step further with its Aircap wind deflector and a draft stop mounted permanently behind the rear seats. Mercedes says this limits the amount of wind intrusion into the E-Class's passenger cabin up to speeds of 160 km/h. Perhaps one of the biggest advances in convertible comfort is the widespread use of folding metal hardtops. Although Ford's 1957 Skyliner is considered an early example, the first truly reliable and functional retractable hardtop was the 1997 Mercedes-Benz SLK Roadster There is a compromise in trunk space when retractable hardtops are stored compared to a traditional cloth top, but the convenience, comfort and safety of closed-body motoring – at the touch of a button – has become popular. Audi's 2010 A5 Cabriolet, like the new E-Class, sticks with a cloth top. But that doesn't mean it's noisier than competitors from Infiniti and BMW with retractable hardtops. The A5 features an optional acoustic top with a layer of insulating foam that reduces wind noise even further. Comfort may be king, but the convertible nearly went away for good because of more stringent crash and rollover regulations and consumers' increasing awareness about car safety. But since the last '76 Eldorado, carmakers have been forced to make convertibles as safe as closed-body cars. Rollover protection bars mounted in the rear head-restraints have been a boon to safety. If sensors in the airbag control unit detect imminent danger to occupants, pre-tensioned pressure springs are activated by pyrotechnic means – in other words, extremely quickly. Convertible makers also take other structural precautions to make up for the lack of a roof. The Volvo C70 convertible uses ultra-high-strength steel in its doors and floor members to direct energy underneath the occupants. As well, Volvo installs a door-mounted inflatable air curtain. In the event of a collision, the curtain extends upward from the door and remains inflated for up to five seconds, helping protect occupants from debris and other flying objects.

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