Corvette: A Legacy - Chapter One: The Birth of the Corvette #BlogPost

Corvette: A Legacy (Directory)
Prologue: The Ancestors to Sports Cars - https://www.carthrottle.com/post/n4ell2q/
Chapter One: The Birth of the Corvette - https://www.carthrottle.com/post/woo5dod/
Chapter Two: Steps and Stumbles - https://www.carthrottle.com/post/wmk6d7r/

Postwar America had a ravenous appetite for new cars and other items that were not available in large numbers during World War Two. After this war, an air of prosperity and optimistic views began to take the nation by storm, with many enthusiasts giving more than a simple stare at the growing group of sports cars that were being imported from other countries, especially at England’s MG TC. With many brand new models coming from automakers to dealerships and then into garages, the late 1940’s signaled how automakers wanted to resort to “selling the sizzle instead of the steak” in that they would sell the experience of the car rather than the car itself in order to keep a high sales pace.

Soon, the words “dream car” entered the public’s diction. Automakers would draft wild concepts not just to show how creative their designers were and how imaginative their engineers were, but also to see how interested the public was of such ideas and to see if they would accept a new design language and features.

Futuristic Visions

The term “dream car” entered the lexicon when Harley J. Earl, the founder and head of General Motors’s Art and Colour Section, the American auto industry’s first in-house styling department, designed the Buick Y-Job in 1938.

This was the first concept car ever made, designed as a long, low, two-seat convertible that would portray the company’s themes for car design preceding and following the Second World War; it revealed the benefits of giving the public an inkling of what was to come in General Motors’s production-based offerings, with the General enjoying large amounts of successes with its Motorama expositions that were held from 1949 to 1961. Being gatherings of the finest chrome, choreography, and creations that were to be offered, it showcased the company’s current cars and gave a sneak preview of the future with its concept cars.

Earl had a passion for taking on experimental projects, and this became a part of his job after working on General Motors’s 1949 and 1950 models, which included the Buick Roadmaster Riviera and Cadillac Coupe deVille. Earl’s first postwar dream cars were the aircraft-inspired Buick LeSabre and the Buick XP-300, with both being shown in 1951. Both cars had such advanced ideas of a wraparound windshield, a folding top that was hidden under a metal cover behind the cockpit, a sculptured rear deck with two tail fins, and a lowered stance.

After designing these two, in the fall of 1951, Earl turned to drafting a concept for a low-priced, sporty car. He believed it was possible to outsell the foreign sports cars that were garnering attention from the aficionados by building a car that offered more of the car for less of the cost and had the benefit of being sold and serviced at a dealer. Earl was able to access a small enclosure that was contiguous to the company’s Body Development Studio; in here, he could work in private with a personal crew on any project that he wanted to hide from the public before it was released. In here, the Corvette would reach its inception.

"Project Opel"

Earl wanted the sports car to be priced around $2,000 ($18,462.08 when adjusted for last year’s inflation), which was a 15% decrease from the MG TD’s cost. To experiment with the design, he designed a few initial design studies and scale models, which were reported to be similar to bare-bones British roadsters of that time and were based on a stock chassis from General Motors.

Earl was also inspired by one concept car that was displayed for some time in the General Motors Styling auditorium. Known as Alembic 1, its chassis and engine were wrapped in a fiberglass body that was originally designed by Bill Tritt for the United States Rubber Company. Tritt founded a company called Glasspar, which was known in the early 1950’s for its kit-car bodies that were made of glass-reinforced plastic, also known as fiberglass, which was lighter than the steel used in many cars at that time.

To keep the car a secret, Earl named the car “Project Opel,” chosen to confuse outsiders particularly because Chevrolet frequently advanced studies for General Motors’s German subsidiary at the time. A select group of people were chosen to have access to the project to keep the project a mystery, and any employees that were not directly involved in the project may not have even known of Project Opel.

Around this time, Edward N. Cole was transferred from General Motors’s Cadillac Division to Chevrolet, where he became the chief engineer and would become involved with the creation of the Corvette. In this new position, Cole tripled Chevrolet’s engineering staff from 850 to 2,900 engineers and then decided to start a venerable line of engines, the small-block V8’s, by designing a 265-cubic-inch V8 that would make its debut in 1955. Earl then tapped Robert F. McLean, a young sports car enthusiast with degrees from the California Institute of Technology in engineering and industrial design, to create a layout for Project Opel.

To design the car, McLean visualized the car from the back forward, not like the tradition practice of starting at the front and going rearward. Keeping the rear axle in mind as a reference point, he laced the engine and passengers as close to that axle as possible with the hope that doing so would result in a perfect 50/50 weight distribution, which was ideal for a sports car’s handling (the final figure was 53/47 percent). Taking a cue from the Jaguar XK120, one of Earl’s favorite sports cars, the wheelbase was set at 102 inches, and with the track being 57 inches in the front and 59 inches in the rear, the concept’s track was wider than the Jaguar’s, but not as wide proportionally as that of the rear-engined Porsches of that time.

The Corvette’s engineering goals would be outlined with several criteria in a technical paper that was delivered to the Society of Automotive Engineers in October of 1953 by Maurice Olley, a veteran engineer of Chevrolet. The paper included an assumed definition of a sports car: a sports car was a car that had a cruising speed of more than 70 miles per hour, a weight-to-power rating of 25 to 1, and, to quote him, “ample brakes and good handling qualities” that included quick steering with light handling, a low center of gravity, a tiny overhang with a low moment of inertia relative to the wheelbase, a firm, smooth suspension, and quick steering response with no oversteer.

Earl’s Art and Colour Section would soon work with General Motor’s engineers, following the LeSabre and XP-300’s design cues to include a panoramic windshield, a toothy oval grille, “definition” at the rear fenders, and a shadow-box rear license-plate frame. It was originally planned for the car to have a steel body, but this was shelved in favor of fiberglass because of how it would allow for highly complex shapes to be crafted without having to stamp steel, which would have been extremely expensive. Such a decision would allow the designers to have more flexibility to form neatly rounded shapes and graceful curves in a small amount of time and with a small amount of money.

Two major questions were asked about the fiberglass construction for the car, which were whether or not the material provided the required structural integrity and whether or not the construction would be feasible for production. The second question could only be answered by giving the car the green light for production, but the first one was accidentally answered. Chevrolet built a full-size convertible with a fiberglass body for investigative purposes in early 1952, and during high-speed testing at the proving ground, the driver unexpectedly rolled the car but suffered no injuries. The car’s body suffered only minor damage, with the doors, hood, and decklid taking no damage; this thoroughly convinced Earl that fiberglass would be the right choice for the shell of his dream car.

Earl wanted the car to be completed in time for the first 1953 Motorama, which would be held in January at the Waldorf-Astoria Hotel in New York. As a result, McLean and his fellow engineers began searching for production chassis and drivetrain components that would be compatible with the fantastic plastic.

A bespoke chassis was needed for the car because of how rigidity was essential to the car’s construction and because of how McLean wanted the engine to be positioned behind the front axle instead of over it. This chassis would weigh a mere 213 pounds, being unique in that it had an X-member design with sturdy box-section siderails. Along with this, the vehicle was unique in its rear end in that instead of using a traditional torque-tube drive at the rear, an open or Hotchkiss drive was utilized, being a first for Chevrolet. Conventional leaf springs were used for the rear suspension, but they were positioned outside of the main frame rails for added stability, with this feature being added for the division’s brand-new passenger cars in 1955.

In the front end of the car, the suspension was borrowed from that of Chevrolet’s then-current passenger cars, but with recalibrated shock rates and a larger-diameter anti-roll bar. For the steering, an off-the-shelf Saginaw recirculating-ball system was used, but the steering ratio was quickened to a 16:1 ratio. The steering idler arm was then redesigned in order to allow the engine to be mounted lower, and the steering wheel itself was one inch smaller in diameter than that of Chevrolet’s passenger cars.

For an engine, only one option was present, and that was the 235.5-cubic-inch (3.9 L) Blue Flame six-cylinder engine with overhead valves, which made a miserly 105 horsepower in its standard guise. In order to boost this figure, a high-lift, long-duration camshaft like the one found in Chevrolet’s 261-cubic-inch (4.3 L) truck engine, solid valve lifters to replace the hydraulic ones, and dual valve springs to cope with the heightened engine speeds. Cast-iron pistons were selected over aluminum because they were more durable, and the head’s casting was adjusted in order to produce an 8.0:1 compression ratio, which was greater than the 7.5:1 compression ratio used in top-of-the-line Chevrolet passenger cars. The water pump’s flow capacity was increased, with the pump itself being lowered at the front of the block so the massive four-blade fan could clear the low hoodline.

To make more power, the original induction system was replaced with triple Carter “YH” sidedraft carburetors that were mounted on an aluminum intake manifold. The carburetors worked together instead of through a progressive linkage, with each carburetor feeding a pair of cylinders through a separate choke. Automatic chokes were initially used, but several tests revealed that all three carburetors could not be synchronized because they did not warm at the same rate, as a result, only the Motorama Corvette had automatic chokes, while the production cars had manual chokes. After this, it was decided that a new rocker-arm cover would be needed to allow the engine to clear the low hoodline, and to remove the one remaining obstruction from fitting the engine in the bay, the oil filler was repositioned toward the rear. Along with this, a special dual-exhaust system was utilized in order to reduce back pressure for more power and a more symphonic exhaust note.

This plethora of changes allowed the straight-six to breathe more freely, producing a variant known as the “Blue Flame Special” that now made 150 horsepower at 4,500 RPM, with a much higher maximum operating speed than this.

The transmission selected to manage this engine’s power was a Chevrolet Powerglide two-speed automatic transmission, which was selected for the original Motorama show car. This feature was one of the most controversial on the eventual production car because to purists, the terms “sports car” and “automatic transmission” were mutually exclusive and did not mix well, but the engineering staff did not believe that there was a manual gearbox that was strong enough for the improved engine, and since there was no time to develop a bespoke manual unit, Chevrolet had to utilize the Powerglide.

The transmission was virtually unaltered from its passenger car specifications with the exception that the shift points were raised to match the new engine’s eleven-percent increase in torque (now at 223 lb-ft of torque from approximately 201 lb-ft of torque). Several tests revealed that the stock transmission oil cooler was not necessary in this lightweight car, and as a result, all oil lines that were running forward to the cooler were plugged. The shift control was floor-mounted because of both practical and aesthetic reasons.

Wearing a fiberglass body, the Motorama car’s body panels were a fifth of an inch thick and were hand-laid into a mold that was cast from Earl’s preproduction full-size plaster styling model; as a result, the body was made of nine major subassemblies that consisted of the floorpan, the trunklid, the top cover, each door, the hood, the front fenders and nose, the front gravel pan, and the rear fenders and gravel pan. With this show car almost complete, Cole was able, because of his new position within Chevrolet, to be one of the first people to see the fiberglass-based concept. Falling immediately in love with it, he promised to support Earl in his efforts to bring the car to production, going to the General Motors Building’s fourteenth floor executive suite and asking company president Harlow Curtice to take a look at the car.

Earl took Curtice and Chevrolet’s general manager Thomas H. Keating on a walk-around tour of a full-scale model fashioned from plaster. Earl explained that the car was not only a profitable product, but also one that would introduce a sporty image which would vitalize Chevrolet’s image as being more than a family car company. Such persuasion worked effectively, with the car being approved for the 1953 Motorama show. At this time, it was decided that the engineering staff should work on another car with the idea that this car would enter production, being known as Project EX-122, with the final decisions for the car being based primarily on the reactions of those who saw it.

What, however, would the concept be named?

In late 1952, the top executives at Chevrolet met to decide on what Earl’s dream car would be named. 300 names were proposed, but they were all rejected on the grounds that they were unsuitable. Eventually, Chevrolet’s assistant advertising manager, Myron Scott, found one that fit the car. While reading a dictionary, he found the word “corvette,” which was defined as “a type of small, agile 19th century warship.” The name implied speed, strength, and maneuverability, which were all in line with the car’s ethos of being powerful and nimble, and intriguingly, one early press release stated that the car was named “Courvette,” which was using the British spelling of the word.

Finished in striking Polo White with a resplendent Sportsman Red interior, the Corvette was a showstopper at the 1953 Motorama, shocking many with its departure from the family cars that were found everywhere else in the show, and people began asking if the car would reach production and for how much it would sell. Due to this acclaim that the show car garnered, Chevrolet decided that the car needed to go into production as soon as possible; incredibly, the production version was available in June of that year, being sold as 1953 models.

Corvette entered production with its styling almost unchanged from its show car version, with the one exception of the cowl-mounted air scoops, which would return without any function on the 1956 and 1957 Corvettes. The fact that Earl’s original concept of the car was not modified by any committees was incredible, and it enhances the appeal of early Corvettes for collectors and enthusiasts. Not only has this body style aged well, but it also is a classic and stays that way over 60 years later.

However, Harvey Earl, Ed Cole, and the many people at Chevrolet would soon discover that designing and engineering a prototype sports car and actually bringing it to production to sell for a profit were two different things.