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Forgotten TDX coupe showed a frameless fiberglassed future

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The TDX at the 2013 Hemmings Motor News Concours d’Elegance. Hemmings file photo.

Space Age materials. New units of measurement for speed. Retro rockets. Pat Amendolia’s TDX encapsulated his vision of a future full of innovative cars that emphasized safety without sacrificing styling or speed. Though that vision never saw widespread acceptance, the TDX itself has survived the last 50 years intact and will continue to showcase Pat’s ideas thanks to a pending restoration by Pat’s own son.

Pat envisioned the TDX in the fall of 1965 as a sort of “three-dimensional resume” to show off his knowledge and skills. Though an electronics repairman by trade, he’s dabbled in all sorts of inventions, from pyrotechnics and rocket propellant to medical equipment. He also developed an early interest in fiberglass for automotive uses, starting with a racing special he put together in 1953. Initially a drag racer with a modern Chevrolet six-cylinder engine installed in a 1926 Chevrolet roadster, the project morphed into an SCCA entry once he designed a flat and sleek fiberglass body for it.

At about the same time, Pat helped build the fiberglass bodies for the Rockefeller Yankee, a sports car that narrowly beat the Chevrolet Corvette to market, and in later years he produced fiberglass-bodied children’s cars and quarter-midgets. The latter project, in fact, used fiberglass not just for the body but for the entire monocoque structure. “It ended up being like a giant torsion bar,” he said. “It flexed enough where the little car didn’t need any suspension.”

He figured the concept could work on a fullsize car if he stiffened it up enough, so he started to work out his own plans for that fullsize car. Pat knew he wanted a Chevrolet V-8 and a manual transmission for the car, and after spending plenty of time in parking lots under cars looking at chassis and suspension setups he decided on a 1955 or later Chevrolet chassis with a ball-joint front coil spring suspension as the basis of his car’s chassis.

“I just wanted the running gear to test the car, I didn’t need the body or the frame,” he said. He kept an eye out for a car that would fit the bill and found one, a 283-powered 1958 Chevrolet four-door sedan, alongside a house not far from where he lived on Long Island. It was a former taxicab with the dents to prove it, and the owner didn’t really feel like selling it. “I wanted that car so bad, my sanity must have slipped a little more than usual. Inventors are like that – we’re a little crazy to start with, and then we become obsessed.” So obsessed, he said, that he traded his family car, a 1958 Plymouth four-door hardtop that he’d recently repainted and fit with new seat covers, for the clunker Chevrolet.

Working off of his plans, he set the car’s wheelbase at 99 inches and began to lay out the body structure using a sandwich of fiberglass over a urethane foam filling. All of the suspension mounting points were integrated into the body structure as part of his plan to dispense with any form of metal chassis. As a December 1968 Motor Trend article on Pat noted, he wasn’t “shooting for making a steel car out of plastics. (Instead he wanted) the advantages of the given material to dictate the construction design.”

Pat also baked a number of safety features into the car’s design. According to the Motor Trend article, he believed that fiberglass would absorb more impact from a crash than metal would. As for the most significant non-fiberglass component, he intended the engine and transmission to be shunted downward rather than rearward in the event of a front-end collision. A Firestone fuel cell replaced the bomb-waiting-to-happen gas tank. Red-to-green color-change warning lights (which Pat later patented) replaced gauges to allow the driver to keep his eyes on the road at speed. To avoid collisions altogether, he intended the car to have an entirely unobstructed forward view, so he included a cantilevered roof design that negated the need for A-pillars. And he designed a unique retro-rocket emergency brake.

“I figured that with no crossmembers under the car, you can get a retro rocket set at just the right angle to slow the car down,” he said. “I just had a gut feeling that it would work – I never calculated the right size rocket or whether it was even possible to slow the car down that way – but I put a six-inch tube under the car from the tail to just under the engine anyway. I also contacted Aerojet General, and while they didn’t have anything that size, they didn’t poo-poo the idea either. Of course, there’s no guarantee the rocket wouldn’t go off on its own for some silly reason.”

Photo courtesy Pat Amendolia.

While he described himself as “do-it-yourself to the point where it gets ridiculous,” Pat did hire a worker to take his tacked-together fiberglass body layout and build it up to as thick as three-quarters of an inch in places. Pat said it came out rigid, despite the naysayers who warned him that the car would sag under its own weight.

In addition to the fiberglass monocoque, Pat also designed polycarbonate covers for the headlamps and a polycarbonate backlite to give the car a fastback profile. He also intended it to use a polycarbonate driveshaft and had Bayer’s Mobay division fabricate one for him, but due to a miscalculation, it twisted the first time he tried applying any sort of above-idle torque to it.

Pat holding the twisted driveshaft. Photo by Geoff Hacker.

Pat did get the TDX – which took its name after his daughter’s nickname, Teedee – running, roadworthy, registered, insured, and inspected, but he never finished the interior or paint. He never formally showed it either, despite plans to follow it up with a production TDX that would have used a Jaguar torsion bar suspension and independent rear suspension. Other than the Motor Trend article, it never drew much attention, and he put about 500 miles on it before other projects diverted his attention.

“It was a good performing car,” he said. “I was surprised how well it rode.”

Eventually, he rolled it out to the edge of the woods on his property, where falling tree limbs took out the windshield, the salt spray in the air from the Long Island Sound rusted up the metal components, and the engine seized over the next few decades.

Photos by Geoff Hacker.

While it has in the last several years moved from its spot with the help of Pat’s sons Joe and Bill – notably to the Hemmings Motor News Concours d’Elegance in 2013 to take part in that year’s fiberglass cars class – it hasn’t run since Pat had it on the road in the late Sixties.

That’ll soon change, however, now that Joe has agreed to take on the car’s restoration. He’s already located another 1966 283-cu-in V-8, and pat has provided a number of fittings to complete the TDX’s interior, including the red-to-green warning lights.

“My instructions to my son were to not improve anything in the car,” Pat said. “Everything has to be the way it was unless it wasn’t completed originally. This was a concept car, after all.”