The Chevrolet Corvette was not the first car with a fiberglass body. But after 50 years and with production exceeding 1.3 million units, it remains an icon in the world of materials innovations.
The '04 Corvette Commemorative Edition Z06 once again breaks new ground with a carbon-fiber hood that weighs only 20.5 lbs. (9 kg), a third less than the standard hood made from sheet molding composite (SMC). The inner hood is a composite of SMC and carbon fiber.
Although some panels in the '03 Dodge Viper feature carbon-fiber composites and the body of the ultra-expensive Mercedes Maybach is made of the space-age material, Chevrolet claims the Z06 hood is the first OE-painted exterior carbon-fiber panel on a North-American-produced vehicle.
Thus, carbon fiber joins a long list of Corvette materials breakthroughs that range from aluminum (radiators, engines, suspensions and body components), steel (hydroformed tunnels and rails), recycled SMC (rear inner panels) and titanium (exhaust systems).
The very first “plastic-body” car, however, resides in the Detroit Historical Museum. It's called Scarab and was developed in secrecy during 1944-'45 by the Graham-Paige Motor Co., funded with $100,000 from Owens Corning Corp., a pioneer in glass technology. The Scarab never made it into production and Graham-Paige soon moved into the history books.
Corvette almost didn't make it, either. While it created a sensation when it was first shown at theCorp. Motorama in New York in January 1953, sales didn't match the excitement. GM built 300 that first year but had planned on 10,000 in 1954. Only 3,640 were produced, and the 10,000 mark wasn't reached until 1960.
Sales were sluggish in the '50s because Corvette looked great but wasn't a true sports car in the European tradition that GM styling chief Harley Earl envisioned. Powered by a standard Chevy 150-hp inline 6-cyl. mated to — yes — a 2-speed PowerGlide automatic transmission, it was a sports car in name only.
GM's sharp-eyed financial folks may have pulled the plug had it not been for introduction ofMotor Co.'s Thunderbird 2-seater in 1955, which became an immediate hit. That opinion is shared by many, including Robert Morrison, the founder (in 1948) and chairman of Molded Fiberglass Corp. (MFG) of Ashtabula, OH, who died a year ago at age 92.
Morrison's company was a pioneer in fiberglass molding technology and he worked closely with GM and Chevrolet in developing and perfecting the body panels in the '50s. Recalling those days in a memoir he wrote around 1980, Morrison observed: “I believe, but of course cannot prove, that Chevrolet would have completely cancelled the Corvette if theThunderbird had not been such a big success.”
The T-Bird began edging up in size in 1958, abandoning its heritage and leaving Corvette as the sole volume-built U.S. sports car. A retro-T-Bird returned in 2002, but has fizzled and is being phased out by 2005.
Corvette, meantime, has gone through five generations with the sixth — dubbed the C6 — due to arrive as the T-Bird departs two years from now. That year also will mark the 50th anniversary of Corvette's metamorphosis from a sleek-looking sportster to a true performance car with the debut of Chevy's small-block V-8. The 195-hp engine developed by the legendary Ed Cole, who later became GM's president, powered the equally legendary '55 BelAir and was quickly adopted by the 'Vette.
Under the guidance of the late genius Zora Arkus-Duntov, who joined GM in 1953 and became Corvette chief engineer in 1968, Corvette roared off on the performance trail and has never looked back. In 1956 the V-8 was boosted to 240 hp, and by 2003 output in top-performing models hit 405 hp.
A perennial winner or close finisher on racing courses around the world, Corvette has become a Yankee phenomenon with legions of fans, including 22,000 in Corvette Clubs.
“We never quit on the brand,” says Gary Cowger, GM president-North America, “and its heritage as an affordable sports car.” Yes, compared to a Ferrari, but still a tad steep for many pocketbooks at $51,000-plus for a top '03 vs. $3,500 for the '53.
Bob Lutz, GM vice chairman and product development chief, recalls the first 'Vette he saw. “It was a ‘Blue Flame Special,’ but it had no respect from foreign-car aficionados. Fighter pilots (he was one in the Marine Corps) wanted a Jaguar or Austin Healy. A 2-speed automatic was not going to make it. Performance was modest at best.
“By 1958 we had a fuel-injected V-8, but what attracted me to GM when I was in graduate school was the '63 split-rear-window job with fully independent suspension,” Lutz continues. “It's gone from a joke, as treated by the European press, to absolute world-class performance.”
Dave Hill, Corvette chief engineer for the last 10-1/2 years, also heads the Cadillac XLR luxury sports car engineering group.
The XLR will debut next month and is built in Bowling Green, KY, alongside Corvette, using some of the same components.
Cowger doesn't see the two cars competing with each other. Price is one big difference — $20,000 or so separates them — but Lutz says XLR exudes “refined, silky performance,” compared to “the raw, visceral brutality of Corvette.”
Fiberglass vs. Steel
The first Corvette wasn't known for brutality, especially when the accelerator was stomped. But with it Harley Earl got the car he had long coveted.
The tempo picked up when a one-off fiberglass-body sports car built off a Jeep by an Air Force officer for his wife arrived in Detroit in 1951.
Built in California, the project was backed by the U.S. Tire and Rubber Co. (later Uniroyal), which was looking for new automotive business.
GM had experimented with fiberglass on Cadillac, Buick, Oldsmobile, Pontiac and Chevy concepts, but all were large, basically family cars.
Earl showed the proposed new car to GM President Harlow Curtice in May 1952, and approval followed a month later. To save time, the show car's body was made of fiberglass, and the car was completed in December in time for the New York unveiling. It was engineered, however, to be built from steel.
Curtice was so impressed by the car's reception that he scrapped plans for steel and ordered that the body be made of fiberglass. With only five months before production startup in June, GM engineers and manufacturing experts scurried and worked 7-day weeks to get it ready.
Fiberglass had been used since World War II for military applications and by the early '50s was widely replacing wood in pleasure boats. MFG and Owens Corning were by then industry leaders in the new technology, and at one time MFG made boats under its own name.
Glen Warner, a 30-year MFG veteran and Robert Morrison's son-in-law, currently is vice president-New Products. He recalls the so-called “elevator incident.” Morrison had come to Detroit to discuss what MFG could do to support GM, but the two purchasing people he was to meet were off talking with suppliers about steel body components.
By chance, says Warner, Morrison was about to leave when he punched his floor, the door opened and there stood Purchasing Director Elmer Gormesen, who said the decision to make the car from steel had been made a day before. GM was hesitant about fiberglass, he said, because it planned for 10,000 units, and there was no existing capacity. Morrison assured Gormesen that MFG and OC could meet GM's requirements.
Morrison had other business in Detroit and didn't return to Ashtabula until 1:30 a.m. the next day. That's when he learned from Gormesen during a late-night phone call that GM had decided to go with fiberglass.
Noland Adams, who has chronicled Corvette in numerous books and articles, says GM borrowed heavily from marine technology to shape the first Corvettes using the “lay-up” method, in which pieces of fiberglass cloth are cut and laid in place over a female mold.
“Resin is mixed and brushed over and into the material,” Adams writes, and “then rollers are used to force the moistened material into the crevices of the mold while forcing air out of the fiberglass,” then allowed to cure overnight.
Crude by today's standards, the technology — since enhanced — still is used for some applications. It worked for Corvette, and the first volume-production, rustproof, lightweight car bodies were born.
Improvements in surface finish and other nagging problems came rapidly, but the next big breakthrough came in 1966 with introduction of SMC.
Bob Vogeli, chief of Chevrolet Body Engineering from 1963-'84 and now retired in Hendersonville, NC, says he liked working with Duntov. “He thought the body was something to hold the parts on,” he quips.
Constantly seeking better materials and methods to make the panels, Vogeli says Chevy moved from the lay-up method to the “dry-mat preform” method in which flat parts were cut from fiberglass, laid in a die and resin added. “It was complicated and labor intensive,” he says.
SMC proved to be simpler to fabricate because glass, filler and resin were combined in mats that could be “cut to size, put in a die and closed (for curing.) It saved labor and there was much better control around the edges of the material.”
Vogeli says he fought with Morrison over switching to SMC “for one reason: His plant was set up around the old system. He said SMC would never make it.”
MFG never has heartily embraced SMC, says Warner, although it does make SMC components for a variety of applications. The company sold the bulk of its Molded Fiber Glass Body Co. subsidiary, and with it most of its Corvette business, in the early 1960s to Rockwell International Corp. (part of which now is ArvinMeritor Inc.).
With new primer technology, the recent advent of “tough Class A (TCA)” SMC all but eliminates microcracks or “pops” in panel surfaces, Warner says. Despite SMC's resounding success in body and structural applications, MFG still prefers the pre-form method “because it makes better parts.”
Corvette 1952-2004: A History of Materials Innovation
1952: EX-122 concept show car hand-built. Becomes forerunner of Corvette.
1953: Corvette unveiled in New York. Fiberglass chosen for production, which starts in Flint, MI, on June 30. First-year build: 300, all Polo White. Designer Zora Arkus-Duntov — who becomes Corvette chief engineer in 1968 — joins GM. Production moves to St. Louis in December.
1954: 3,400 built. Blue, red and black colors added.
1955: New small-block V-8 (195-hp) introduced (prior models powered by 150-hp 6-cyl. engines).
1956: Fiberglass removable hardtop introduced.
1957: Fuel injection, a U.S. first, debuts. Anodized aluminum trim bows on interior.
1958: Quad headlamps introduced.
1962: Aluminum radiator replaces copper.
1963: Sting Ray version introduced.
1965: Disc brakes replace drums.
1966: First sheet-molded composite (SMC) used for front body panels and hood.
1970: Plenum and instrument panel support panels switch to SMC.
1971: Rear quarter and end panels switch to SMC.
1973: Soft front bumpers to meet federal 5 mph (8 km/h) impact standard, add 35 lbs (16 kg) and 2 ins. (5 cm) to length.
1974: Duntov, who developed Corvette into high-performance car, retires.
1975: Plastic fuel-tank bladder bows.
1976: “Last” convertible built. Returns in 1986.
1978: In 25th year, 46,776 built, with starting price of $9,351.89.
1981: Assembly switches to Bowling Green, KY, from St. Louis, where last '82 was built. No '83 model, as plant shift takes place. Fiberglass-reinforced rear leaf springs debut.
1984: One-piece, lift-off SMC roof panels with massive rear glass introduced.
1986: Aluminum cylinder heads and antilock braking systems added.
1989: Airbags and 6-speed transmission introduced.
1992: 1 millionth Corvette built on July 2.
1993: Rear inner panels molded from recycled SMC, an industry first.
1994: National Corvette Museum opens in Bowling Green. Leather seats become standard for all models.
1997: All-new, fifth-generation model bows with major suspension components fabricated from aluminum. High-tech hydroformed steel used for driveshaft “tunnel.” Windshield frame and IP supports switch to aluminum.
1999: Rear “tub” and front floor panels switch to lightweight balsa composite. First fixed-roof hardtop since '68 debuts.
2000: Lightweight titanium debuts for Corvette Z06 exhaust system.
2003: An estimated 35,000 models will be built, pushing 50-year output to more than 1.3 million.
2004: Carbon-fiber hood introduced for Z06, cutting weight in half.
Source: GM, Chevrolet and industry sources.
First Corvette Still Exists
NASHVILLE, TN — The very first Corvette — the ones aging Americans would have seen if they'd visitedCorp.'s Motorama at the Waldorf-Astoria in New York a half-century ago — still exists.
It was among thousands of ‘Vettes of all ages on hand for the car's 50th anniversary here. As part of the celebration, Nashville hosted a giant downtown parade complete with marching bands, during which Corvettes, ranging in order from 1953 to 2003, took center stage. Drivers gave the crowd lining the route a medley of revved-up engine music.
The first Corvette didn't participate in the parade, but a look-alike sufficed. Designated the EX 122, the first fully equipped Corvette was developed in the Experimental Department of Chevrolet Engineering in Detroit during late 1952 as a concept car for the Motorama exhibit and later appeared at other auto shows.
Although it was hand-built, the parts and components met production drawings so that the EX 122 was close to the actual car that went into production on June 30, 1953. After making the rounds, the EX 122 wound up on display at the GM Building in Detroit. It eventually was returned to Chevy Engineering where it was used as a test bed for the new small-block V-8 Chevy had engineered for its '55 models. The engine ran up 25,000 miles (40,000 km) of durability testing at GM's Milford, MI, Proving Ground. Chevy then dropped the car's original inline 6-cyl. engine for the V-8.
R.F. Sanders, who then headed the Experimental Department, had the car totally refurbished and bought it himself in 1956. He sold it in April 1959 to Russell Sanders, who re-sold it six months later to Jack Engle.
The Kerbeck family, which operates a Chevrolet dealership in Atlantic City, NJ, bought the EX 122 on July 22 and is the current owner.
— David C. Smith