Jet Cars Part 4: Socema Gregoire, and Early Turbines from GM, Chrysler & Rover

You probably thought we'd finished dealing with the subject of turbine-powered cars back when we completed Part 3 of our Jet Cars series*.  But recently an old friend and patient reader of these meandering commentaries sent me this postcard of something called, for short, the Cemo Turbo. It's the Socema Gregoire from 1952, powered not by a turbocharged piston engine, but by kerosene-fueled jet turbine gulping air through that chromed, circular air intake.

The chassis design, by Jean-Albert Gregoire, was based on his aluminum-intensive Hotchkiss platform. Though it lacked that car's front-wheel drive, Gregoire's decision to mount the engine forward of the front wheels meant that it shared the large front overhang to wheelbase ratio of the Hotchkiss.  Location of the fuel tank (the oval shape behind the front seats, below) meant there was no rear seating. The fuel tank needed to be a large one, as early turbines were thirsty. They also produced lots of heat, which along with their demanding metallurgy and resulting high cost, offset their relative simplicity compared to internal combustion engines. Automotive turbines featured about 1/5 the number of moving parts as the average piston engine, but they were expensive parts...

In the photo at the left below, engineer Gregoire stands next to the partially-completed, handmade aluminum shell designed by Carlo Delaisse. The body was built at the Hotchkiss firm's Paris automobile factory, which was then in its final days after attempting to work out the flaws in Gregoire's front-drive boxer four-cylinder sedan design, of which Hotchkiss made around 250 before bankruptcy. Though body designer Delaisse was, unlike Gregoire, reported to be publicity shy, and we wonder if that's him sitting in the completed car at right...

With most French luxury cars of this era, the bodywork was the highpoint because it was more modern, in appearance if not construction, than the pre-war chassis designs featured by Talbot-Lago, Bugatti, Delage and Hotchkiss. In the case of the Socema turbine car, the smoothly-contoured bodywork was notable because it was more thoroughly worked out than the Jet Age chassis it covered. The claimed Cx for the body was 0.19. But it's not clear whether those aerodynamic contours ever got a real test outside a wind tunnel...

No videos or even still photos could be found showing the Socema Gregoire being tested, or even in motion.  One British journalist who examined the car suggested that with the engine mounted in front and with no heat exchangers to recapture exhaust heat, temperature gain in the cabin would likely have been excessive.  Like many of J. A. Gregoire's engineering works, the Socema Gregoire was more effective at generating publicity than in delivering performance on the road.  Pretty, though...

If the Socema Gregoire wound up being more show biz than serious experiment, Firebird 1 by General Motors (at far left below) was a flat-out exercise in Hollywood sci-fi. Harley Earl's appropriation of jet fighter styling on this 1953 Motorama show car meant there was only room for the driver under the bubble canopy. There was no heat exchanger to reduce the 1,250 degree exhaust temperature, and only drum brakes to handle 370 hp, though the drums were finned for cooling.  Firebird II, the center car from the 1956 Motorama, at least had seats for 4, and two features that would show up years later on the Corvette: 4-wheel disc brakes and 4-wheel independent suspension. Like turbines already tested by Chrysler, it had a heat exchanger to lower exhaust temperature and improve economy. Concerns about economy apparently went out the window with Firebird III, designed for the 1959 Motorama by Harley Earl (who else?), with its turbine engine supplemented by a two-cylinder gasoline unit to "run the accessories." Hapless occupants were housed in separate bubbles and perhaps limited to communicating by hand signals.  The bodywork relapsed into a hopeless imitation of fighter plane imagery; after the comparitvely sedate Firebird II with its lonely fin in the center of the deck, seven (7) fins festooned the sides and rear of Firebird III. Perhaps the gasoline engine to run the accessories was added to placate oil industry lobbyists; after all, the turbine would run on peanut oil or alcohol.

Meanwhile, over at Chrysler Corporation, engineer George Huebner (at right below) was taking an approach based on solving the turbine's practical problems rather than showing off its sci-fi aspects. Few cars could've looked more practical than the '54 Plymouth sedan that housed Chrysler's automotive turbine. Like later GM efforts and Rover's 2nd generation turbine, the engine relied on heat exchangers to capture heat from the exhaust, using it to heat the intake charge and increase fuel economy, which had been dismal on the first turbines...  Rover's 1950 JET 1 managed 6 mpg, but set a speed record of over 152 mph.

In the photo below, engineers in hats marvel at the low exhaust temperature on the running turbine Plymouth, showing the effectiveness of the new heat exchangers.

Unlike GM and more like Chrysler, Rover in Britain took a practical rather than show-biz approach to solving the problems of turbine car performance.  With their first Jet 1 appearing in 1950, they adopted a mid-rear engine location to put noise and heat behind the cabin.  By the time their T3 was tested in 1956, Rover had adopted an engine location behind the rear wheels to allow more cabin space, all-wheel drive to handle the engine's torque, a De Dion rear axle, and fiberglass bodywork with a low beltline and large windows.  Like Chrysler, they employed a heat exchanger to improve efficiency.  Performance was lively for the era, with 0 to 60 taking 10 seconds and 0 to 80 taking 17.7. The T3 set the stage for the T4 which appeared in 1961, a couple years before Chrysler built 50 Turbine Cars for consumer testing, and also before a series of Rover-BRM turbine-powered Le Mans racers. That Le Mans effort is another forgotten episode of the turbine car saga, one we'll save for Jet Cars Part 5...

*Footnote:  "Jet Cars Part 1: Real & Not So Real", appeared in these posts on May 21, 2016. "Jet Cars Part 2: Chrysler Turbine Car" reviewed the history of the only turbine-powered car ever released for testing by the public, also on May 21, 2016.  "Jet Cars Part 3: Chrysler Turbine Epilogue" reviewed the reasons Chrysler discontinued its Turbine Car program, and appeared May 25, 2016. 

Photo Credits:
Top:  Photo by the author; postcard courtesy of Doug Pletcher

2nd + 3rd & 4th (side-by-side):  alternathistory.com

5th & 6th:  Wikimedia

7th (GM Firebirds):  General Motors, featured on carnewscafe.com  

8th & 9th: Chrysler Corporation

10th:  Wikimedia