WHEN the green flag fell at the rain-plagued 70th running of the Indianapolis 500, leading the 33-car pack was a lightning-swift Chevrolet Corvette convertible with famed test pilot Chuck Yeager, the first man to exceed the speed of sound, at the wheel. Not only is it the pace car for one of the world's great auto races, but it's also the first factory-built Corvette ragtop since 1975. The pace-car 'Vette points up the sharp rebound in soft-top automobiles since the much-ballyhooed ``demise'' of the convertible a decade ago.
A ragtop automobile is an adventure, no matter where it's built. For the adult, it can be a retreat in time -- perhaps to those earlier days when the world of responsibilities still lay ahead. And for youth, it fulfills a wish to ``spread one's wings,'' cruising the highways and back roads with a freedom and zest that can never be found in an enclosed car.
Indeed, despite the remembered idiosyncrasies of open-air motoring, with its squeaks and groans and the likelihood of a sudden rain shower finding its way inside the car even with the roof up, there was an exhilaration that is hard to describe.
So when General Motors decided to ``dump the ragtop'' in 1976, the open-top automobile refused to go away. Dozens of small conversion companies drove into the void, slicing the tops off coupes and sedans, stiffening the structure, and putting on fabric. One company, Coach Builders Ltd. of High Springs, Fla., has sold at least 30 different soft-top models over the years, including the Continental Mark VII, Cadillac Seville, and Jaguar XJ-S.
Sensing a new sales opportunity after its retreat from the brink of bankruptcy, Chrysler Corporation in 1982 led the charge back to the ragtop. Now, all the domestic carmakers are back at the wheel, even though the demand is said to be far less than it was a generation ago. And today's convertibles are far better than they've ever been before, with fewer squeaks and full-strength air conditioners that help to compensate for the blazing overhead sun.
In the 1960s about 10 percent of all new-car output was convertibles. Today the demand is running at 1 percent of industry sales, according to David H. Hall, marketing plans manager of the Ford division. ``It could go up to 1.4 or 1.5 percent,'' he predicts, ``but we do not see the volume approaching the level where you'd want to have an entry in each and every market segment.'' Ford, for example, now sells about 16,000 Mustang ragtops a year.
Thus, while the market may never return to the heyday of the '60s, when up to a half-million convertibles a year hit the road, the open-to-the-sky automobile may still be the choice for upward of 100,000 car buyers this year, according to some estimates.
Thomas R. Mason, passenger-car marketing manager of Chevrolet, is a little less bullish. ``A hundred thousand convertibles this year sounds high to me,'' he asserts. ``I think the potential is there for 100,000, but I believe that would be the top end of the demand.'' Last year the ragtop figure hit 75,000.
Mr. Mason sees it as ``a specialty market, a niche. There has always been a demand for the roadster and we're trying to take advantage of the demand.'' Each year, Chevrolet expects to sell about 5,000 Corvette soft-tops, which it will produce in its Bowling Green, Ky., assembly plant, plus 6,000 to 8,000 Cavaliers, which American Sunroof will ``convert'' in a new plant in Lordstown, Ohio. Backing off from the trend, however, GM's Buick division dropped the ragtop from its all-new Riviera in 1986.
A decade after it dumped the ragtop, the General Motors Cadillac division has made a deal with Italy's Pininfarina, a highly acclaimed car designer and low-volume manufacturer, to produce an open-top car called the Allante. The bodies of the 1987 Cadillac Allante coupe and convertible will be built by Pininfarina and then shipped via 747 to GM's newest auto plant in Detroit, where the engines and transmissions will be added. The car, aimed at the Mercedes 560SL buyer, is expected to sell for less than $50,000.
Not all ragtops, of course, are in this league. Some -- the Pontiac Sunbird, Ford Mustang, and Volkswagen cabriolet -- sell in the teens.
On the other hand, Rolls-Royce offers its Corniche II for $163,800, while Aston Martin, another low-volume British carmaker, sells the Volante convertible for about $140,000.
Also joining the ragtop band, Maserati will produce a high-luxury, two-seat convertible for Chrysler Corporation, blending the flair of Italian car design with a Chrysler chassis and drivetrain. The front-wheel-drive car will have a 200-horsepower, turbocharged, 4-cylinder Chrysler engine, antilock brakes, and an expected cost of less than $30,000.
Another high performer, the Porsche 911 Carrera cabriolet soars from zero to 60 m.p.h. in 6.3 seconds, with a top speed of 146 m.p.h. Porsche also may market a 944 cabriolet. Erich Bitter, former West German racing champion and now an independent car builder, fields his Bitter SC cabriolet, a $72,500 gem which combines German engineering and elegant Italian coachmanship in a super-low-volume automobile.
Among the domestic carmakers, Renault has an Alliance that combines an open-air ride with a price that starts at less than $11,000. Pontiac's turbocharged Sunbird GT or Chevrolet Cavalier RS compete in the low teens. Chrysler is still a strong contender with its Chrysler Le Baron and Dodge 600, both modestly priced in the $12,000 to $13,000 range. The Mark Cross Town and Country model Chrysler Le Baron hits the price scales at almost $18,000. The simulated wood-panel siding brings back the days of the woodie, but it's far easier to maintain in plastic than it was in wood.
Among other ragtops now on the road are the Alfa Romeo Spider Veloce, Fiat Spider 2000 Turbo, Excalibur Series IV, Buick Riviera, Mercedes-Benz 380SL, and the Porsche 911 SC.
ASC Inc. is building Toyota Celica GT convertibles in a new $5 million plant in Rancho Dominguez, Calif.
The British, who have produced some magnificent cars since World War II, continue to build such limited-output cars as the TVR Tasmin 280i ragtop, among others.
Jaguar now sells the XJ-SC cabriolet, the first open two-seater to be introduced since the last E-Types in 1974, according to Graham W. Whitehead, president of Jaguar Cars Inc. The XJ-SC is not a conventional convertible because it has an integral roof structure with fixed side rails that contribute to torsional stiffness, yet the top is still wide open to the sun. Price: $41,500, plus transportation and dealer-preparation charges.
``The XJ-SC is a very special car for Jaguar,'' according to Mr. Whitehead. ``The addition of the cabriolet gives us the one remaining element buyers have asked for -- open-air motoring,'' he says.
By 1976, all American automakers had ditched the ragtop because of the sharp drop-off in demand. Vinyl tops had become a ``must have'' option even as air conditioning was coming on strong.
Also, there was widespread concern among carmakers that the federal government would legislate tough new safety requirements for ragtops, but the new rules never came about.
One point is clear: While it's showing a new thrust in popularity and demand, the ragtop automobile will never overtake the more traditional kinds of cars, such as the coupe and sedan. Americans also are buying 2-seater cars, 4-wheel-drives, and minivans.
Still, for a high level of fun and a sense of eternal youth on the move, more and more car buyers these days seem to have a yearning to put the top down and cruise with the wind.