Two-Rotor Trendsetter

Chevy’s innovative XP-897 GT prototype foreshadowed mid-engine Corvette concepts to come

Photo: Two-Rotor Trendsetter 1

Story by Joe Greeves

Photos by the author and courtesy GM

June 20, 2019

As you read this, Chevrolet is poised to release the first mid-engine production Corvette in marque history. But while the revolutionary C8 is sure to dominate headlines for the foreseeable future, it’s worth reflecting on the various engineering prototypes that prefigured it, some of whose origins stretch back more than a half-century. Such an opportunity arose earlier this year at the Amelia Island (Florida) Concours d’Elegance, where one of Chevy’s early mid-engine Corvette prototypes served as a featured display.

Moving to the Middle

Back in 1964, the PR team at Chevrolet probably had a subliminal goal when they began tantalizing the public with the Corvette XP-819 show car. In fact, this concept was not a mid-engine at all, but rather a rear-engine prototype fitted with larger rear tires to compensate for the weight bias of the reverse-rotation GM marine engine. Unfortunately this approach didn’t work well in execution, and the car was virtually destroyed in a test-track crash. (It is currently being restored.) XP-819 did, however, create excitement among the Corvette faithful, a response that did not go unnoticed by the trend shapers at GM. Fanning the mid-engine flames soon became a corporate preoccupation, and automotive magazines dutifully followed suit, each breathlessly announcing that such a car was imminent.

Four years later the Astro II XP-880 mid-engine prototype surfaced, its arrival lending additional credence to the notion that Corvette drivers would soon be delighted by the roar of a mighty V-8 rumbling just behind their heads. The Astro II had a big-block mounted backwards and was fitted with a two-speed transaxle from a Pontiac Tempest. Not surprisingly, this light-duty trans wasn’t designed to handle the 7-liter’s massive torque, prompting concerns about long-term reliability. Those fears, combined with the fact that Chevy was selling every front-engine C3 it could build at the time, ultimately spelled doom for XP-880. Its demise, however, did nothing to quell the mid-engine excitement still percolating among performance enthusiasts, especially with newly available offerings such as the Ford GT40, DeTomaso Pantera and Lamborghini Miura proving that such a layout was production feasible (if not cheap).

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The following year Corvette Chief Engineer Zora Arkus-Duntov entered the fray, attempting to solve the Astro II’s transaxle issues by substituting the stouter gearbox from an Oldsmobile Toronado. But while the Olds trans was strong enough to handle the big-block, its weight pushed total powertrain mass beyond what were considered acceptable boundaries. For the mid-engine idea to succeed, Chevrolet would have to find a new, lightweight power source. It would also need to be fuel efficient and, with emissions standards growing ever tighter, clean burning. Clearly, a radical step was warranted.

The Rotary Club

GM had already been experimenting with Felix Wankel’s eccentric engine design and was well aware that, although the rotary had inherent problems, it also boasted several distinct advantages. The three-sided rotor could achieve what amounted to a four-cylinder engine’s power stroke three times in a single rotation. Stack a pair of rotors together, and you had, in essence, a six-cylinder motor with only seven moving parts. Since there were considerably fewer components than were used in a traditional, piston-driven engine, production costs would theoretically be lower.

Finally, because of the compact size and light weight of the rotary, designers could build a smaller car that had more room inside. If higher horsepower numbers were needed in the future, there was the option of simply bolting on another rotor or two. GM even had a three-speed automatic transaxle under development, destined for the upcoming Chevy Citation. All that was necessary was a body.

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GM’s solution was to assign that task to the GM Styling team, headed by Kip Wasenko. The underpinnings of the car began with a shortened version of Porsche’s mid-engined 914, a Targa-topped, two-seat roadster. The suspension, steering and newly designated “Rotary Combustion Engine” (RCE) were installed by GM, but due to space, time and manpower constraints, the body was subcontracted to Italian design firm and coachbuilder Pininfarina. Already actively employed by a number of automotive manufacturers around the world, Pininfarina had the considerable resources needed to accomplish a job of this scale.

A supervisory team from Styling accompanied the chassis to Turin to oversee the process. When they were done, the sleek lines of the resulting hatchback coupe were stunning. Innovations began with futuristic quad headlights never before seen on a U.S. production automobile. They were unique, featuring standard high and low beams along with a “pencil beam” designed for highway use. Concealed windshield wipers and doors that covered the A-pillars helped optimize aerodynamics and minimize wind noise. On the safety front, both bumpers used energy-absorbing polypropylene. Inside, the rigid seats were equipped with seatbelts, along with an adjustable wheel and pedals. A modest 8.1 cubic feet of storage was available in the rear luggage compartment.

The completed XP-897 GT shed its alphanumeric designation and was dubbed the “2-Rotor Corvette.” At just 43.3 inches high, and resplendent in its Candy Apple Red paint, gold wheels and saddle interior, the car debuted to an excited crowd at the 1973 Frankfurt Auto Show. Predictably, rumors once again flew as to whether a mid-engine street Corvette might finally be in the works. But despite the warm reception given XP-897 by magazines and potential buyers alike, the car never progressed beyond the concept stage.

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Several factors contributed to its demise. Even though XP-897 weighed in at a featherweight 2,600 pounds, its 266-cube rotary engine only made 180 hp, less than was considered acceptable to a public accustomed to 300- and 400-hp V-8s. The tiny two-rotor also proved to be considerably dirtier and less fuel efficient than GM’s existing piston engines, which were already struggling to meet new federal standards.

After the car left the European show circuit, it toured the U.S., wrapping up its run at the Spokane World’s Fair in 1974. At that point, the engine was removed and returned to NSU Motorenwerke AG in Germany, which owned the exclusive license to produce Wankel engines at the time. As is generally the case with concept cars, XP-897 was scheduled to be crushed.

Rescue Mission

As luck would have it, XP-897 was spared by a quirk of U.S. importation law. Because the car was listed as a “temporary import” when it first arrived in America, GM couldn’t destroy it without first paying the requisite import duties. Already facing a sizable bill from Pininfarina, the finance team realized the only way to avoid another budget-busting payout was to ship XP-897 back to Europe.

Photo: Two-Rotor Trendsetter 5

The car, minus its engine and transaxle, languished for 10 years at GM’s Vauxhall outpost in Luton, Bedfordshire, England. But an office expansion in 1983 ultimately brought XP-897 out of hiding, and it was once again given a date with the crusher. Geoff Lawson, head of styling at Bedford Trucks in Luton, was charged with carrying out the job, but he decided to call his good friend Tom Falconer instead.

Falconer was the owner of Claremont Corvette, a specialty dealership in England, and the author of a dozen Corvette books. He was also an outspoken advocate of driving and enjoying classic Vettes, rather than allowing them languish, unused, in collections. Since Lawson’s pride and joy happened to be a ’69 427 Corvette convertible, the two men were kindred spirits. Faced with crushing the steel-bodied XP-897, Lawson thought Falconer might like the metal cube as a showroom decoration. After all, the compressed chunk would be significant since it represented about $50 million worth of General Motors R&D.

Falconer instantly knew that the car in question was no ordinary Corvette, but rather the long-lost 2-Rotor show car. He didn’t want the cube—he wanted the whole vehicle. Lawson didn’t have the power to grant his request but suggested that Falconer plead his case to Chuck Jordan, GM’s styling chief at the time. Fortunately, Falconer had made friends in high places over the years, and one happened to be Jordan. Falconer prevailed, and the dusty concept was quietly loaded onto a trailer and taken to his Corvette shop in Newcastle.

Photo: Two-Rotor Trendsetter 6

The restoration process got underway almost immediately, with Falconer adding a Vauxhall Cavalier engine and three-speed automatic just to get the car running, followed later with a more conceptually appropriate two-rotor Mazda motor. With its original Candy Apple Red paint job refreshed, XP-897 was reintroduced to the world in spectacular fashion at a National Corvette Restorers Society gathering in 2000.

Together Again

Though XP-897 was back together and running, Falconer remained committed to returning it to as close to original condition as possible. That meant sourcing a proper GM RCE, but virtually all of these had been melted down. Only one was known to remain, and it was on display at the Ypsilanti (Michigan) Automotive Heritage Museum. Through no small amount of detective work, Falconer determined that one other RCE existed, having been donated to a university years earlier. Following a few phone calls and the transfer of an undisclosed amount of cash, the engine arrived at his shop in 2017. For the first time in more than four decades, XP-897 and a proper RCE were under the same roof.

Once again in the spotlight, the car made another trip across the Atlantic, this time to be featured as part of the Mid-Engine Sports Car Showcase at the 2019 Amelia Island Concours. Throngs of knowledgeable retro-Corvette fans surrounded the one-of-a-kind concept, along with its authentic RCE displayed on a stand next to it. It was a gratifying experience for Falconer, and one especially appreciated by designer Kip Wasenko, who hadn’t seen his handiwork in person since the ’70s.

Photo: Two-Rotor Trendsetter 7

Although Falconer plans to retire soon and sell both the car and its engine, he has high hopes for XP-897’s future. He envisions the freshly rebuilt rotary engine outfitted with a set of suitable exhaust headers and a new intake for the Rochester Quadrajet carburetor, allowing the car to make some live driving appearances accompanied by the characteristic Vrrraaappp! of the Wankel exhaust. Who knows? Maybe it will eventually show up alongside the new C8, providing historical context for this latest, most successful interpretation of the mid-engine Corvette formula.

Sidebar: In His Own Words: Tom Falconer

While at this year’s Amelia Island Concours, we spoke with XP-897 owner Tom Falconer about the process of obtaining and restoring this significant Corvette concept, along with its historically appropriate RC266 rotary engine.
“[The car] was shown all over the world,” he said. “Its last public appearance was at the World’s Fair at Spokane, Washington. Then they shipped it back to England to do more shows in Europe. But then GM abandoned the whole Wankel project because of bad emissions problems. They pulled the engine and returned it to the licensee—because as part of the partner-sharing process, if you quit the program, you had to send all your research back to help others—and shipped the car to Vauxhall, where it sat in a wooden crate with no engine in it for 10 years.
“But then they needed the space, and my friend, who was head of Bedford truck styling at the time, called and said, ‘There is a steel-bodied Corvette at Vauxhall that they are going to crush.’ I thought it might be that rotary-engine concept car, which was rumored to have been destroyed in a fire in California, and it was, and I was able to rescue it. I pleaded with Chuck Jordan. I said, ‘You cannot do this.’ He said, ‘I can see where you’re coming from.’ Then [GM Styling executive] Wayne Cherry said, ‘If you want to take the thing away, take it, but you’ve got to display it in a museum environment. Do not put an engine in it.’ Then he said, almost in the same breath, ‘What engine are you going to put in it?’ [laughs].
“I initially put in a Vauxhall engine, then the one that’s in it now, a Mazda 13B RX-7 rotary. Unfortunately, because of the way that engine is configured, it is in backwards driving through a countershaft gearbox, with spur years, which are noisy. That [pointing to a rotary engine on a stand next to the car] is the correct engine, one of the original GM rotaries. They made about 500 of them. I searched for one for 20 years, and this one turned up just last year. If you love engines like I do, you’ll understand that it’s a lot like a two-stroke. The two-stroke is total genius…so few moving parts to get so much power and so [many] revs. But it’s very hard to control the combustion process, and the rotary has that same problem.” – Gary Witzenburg