Jet Rebel - 1968 Howmet TX

The concept of using aviation gas turbine engines in cars had been gaining a lot of traction in the 1960’s. The space race was still in full swing, jet airline travel was truly taking off, and people were confident everything would be jet and rocket powered in the future. This sentiment lead to Chrysler producing its Turbine passenger car as a  public test bed in 1963, releasing it to select costumers. On the other side of the pond Rover teamed up with BRM to produce a turbine car for Le Mans the 1963 24 hours of Le Mans, and 4 years later Andy Granatelli’s STP-Paxton Turbocar almost won the Indianapolis 500.

At around the same time as the debut of the STP-Paxton Turbocar, American race Ray Heppenstall conceived his own gas turbine powered sportscar. Heppenstall had studied Rover-BRM’s effort, and concluded that a simplified chassis would make the concept a lot more competitive. He shopped his idea around at turbine manufacturers Allison Engine Company and Williams Research, but both declined.

 

The car had its fair share of admirers.

The car had its fair share of admirers.

Totally out of ideas, he asked his old racing buddy Tom Fleming for help. At the time Fleming was vice-president of Howmet Corporation, a company specialized in the manufacture of turbine engine castings. Together they managed to convince Howmet’s board of directors that a competitive racing sportscar would elevate public awareness of the company. Howmet agreed to fund the project and lent its name to it.

There were some issues with the highly experimental turbine car.

There were some issues with the highly experimental turbine car.

Heppenstall initially bought a Cooper Monaco for him to modify into a turbine car, but decided the small British sportscar was not suited to his designs. He sold the Cooper and contracted Bob McKee of McKee Engineering, a racecar manufacturer, to build him two new chassis. McKee based the first model on one of his existing two-year old Can-Am designs, but the second car would be custom-built, allowing it to to fully integrate the innovative turbine concept.

The TX (Turbine eXperimental) was built to FIA Group 6 sportscar regulations. It featured an aluminum spaceframe clad by a streamlined body incorporating gullwing doors for easy access. Suspension-wise, the car was more conventional. It used double wishbones and coil springs front and rear. The car was stopped by disc brakes on all four corners.

The turbine engine showing its exhaust and wastegate pipe (left).

The turbine engine showing its exhaust and wastegate pipe (left).

Power came from a Continental Aviation TS325-1 gas turbine, originally designed for a cancelled military helicopter project. The unit produced 350 horsepower and a monumental 880 nm (650 lb ft) of torque. The engine was capable of spinning at a dizzying 57.000 rpm. Because of the immense torque figure and amazing flexibility of the turbine engine, there was no need for a conventional gearbox. Instead, power was delivered to the rear wheels via reduction gearing.

This setup cause a bit of a problem. As not every track was exactly the same, Heppenstall needed way to change gear ratios. To this end he installed a quick-change differential, enabling him to set the car up for for different tracks. The reduction gear drive also meant the car only had one speed: forward . As a result the car completely lacked a reverse gear. The FIA was not happy with this idea and demanded the car be modified to include reverse. A small electric motor driven by the turbine was installed to make reversing possible and appease the FIA.

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Because a gas turbine engine had a dramatically slower throttle response than a conventional piston engine, a wastegate system was installed on the TX’s Continental. The system would bypass the turbine and regulate the amount of fuel and air entering the engine. This allowed the driver to decrease or increase power without dropping revs and experiencing massive lag.

Another feature of the system was its ability to combat the lack of engine braking encountered with a turbine engine. Without the wastegate the engine's revs would drop down very slowly when the driver released the throttle, resulting in the car hurtling along at the same speed when it should be slowing down. The wastegate's bypassing of the turbine effectively neutralized its power, allowing the car to coast.

Conventional methods to measure displacement did not apply to turbine engines, so the FIA had to come up with an equivalency formula. They calculated the Continental’s displacement at 2960cc, allowing the TX to run in the Under 3000cc category of FIA Group 6. The FIA also gave the car special dispensation to run aviation-spec Jet-A fuel.

The TX made its debut at the 1968 24 Hours of Daytona, the first round of the 1968 International Championship for Makes. Only the custom-built GTP2 chassis was used in the race, with the older McKee-based car being used as back up. It was driven by Ray Heppenstall, Ed Lowther (USA) and Dick Thompson (USA).

The Howmet enjoyed a lot of attention prior to the race, being featured prominently on the advertising poster. The car qualified in 7th position on its first outing. A series of early pit stops for its competitors saw the TX climb up to 3rd in the race. Unfortunately the wastegate failed to re-open on lap 34, resulting in the car having too much power for the corner it was in. It slammed violently into the wall and out of the race.

The exotic machine really struck a chord with the American audience.

The exotic machine really struck a chord with the American audience.

The car was next entered at the 12 Hours of Sebring. The infamously harsh concrete track surface would really put the experimental design to the test, as it was known to completely tear cars apart. Nonetheless the TX qualified an impressive third on the grid behind the #49 Porsche 907 of Jo Siffert (CH)/Hans Hermann (GER) and the #29 Ford GT40 of Jacky Ickx (BEL)/Brian Redman (GB). This time the turbine ran very reliably during the race, but it was hit by flying debris, which shook loose one of its engine mounts. The team was unable to fix the issue, and retired the car after 6 hours.

BOAC 500, Brands Hatch 1968.

BOAC 500, Brands Hatch 1968.

The next round was the BOAC 500 at Brands hatch, where the car qualified in 6th position. Sadly, it crashed out for the second time due to a failing wastegate after just 7 laps. The Howmet team stayed in Britain for the 1-hour sprint race at Oulton Park, handing the wheel to British driver Hugh Dibley. This time the starter motor died during a pit stop, denying the car another chance to finish.

Howmet decided to abandon the International Championship and focus on the American SCCA National Championship instead. There the ambitious project would finally overcome its teething problems. At the Vandergraft Trophy in New Cumberland, West Virginia the car scored an amazing 2nd place finish, setting a new lap record in the process.

The immense heat rising from the gas turbine was one of the TX's defining features.

The immense heat rising from the gas turbine was one of the TX's defining features.

After another retirement at Michigan, the TX was entered into the Heart of Dixie event in Huntsville, Alabama. A short qualifying sprint race was held the day before the race to determine grid positions. The car confidently won the qualifier and was allowed to start on pole position.

The next day the TX would outright dominate the race and take home the victory. At the Marlboro 300 at Trenton Speedway, New Jersey the car repeated the same trick. Ray Heppenstall and Dick Thompson utterly dominated the main event, finishing with a demoralizing 11-lap advantage. The victory was marked the first time in history a gas turbine powered sportscar had taken the checkered flag..

Daytona, 1968.

Daytona, 1968.

Now feeling confident again, Howmet set their sights on the 6 Hours of Watkins Glen, another International Championship event. The #67 GTP1-chassis would be driven by Hugh Dibley and Bob Tullius (USA), with the #76 GTP2 piloted by Heppenstall and Thompson. The cars qualified in 8th (#76) and 9th (#67) respectively.

During the race the factory Porsche entries met an early demise by crashing out, which left the air of TX's in an encouraging 3rd and 4th. Unfortunately the #67 suffered a transmission issue which reduced it to a slow crawl, but #76 soldiered on and captured a 3rd placing and 1st in class.

 

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The cars were then entered into the most prestigious endurance race of all, the 24 Hours of Le Mans. The driver line-up remained the same as it had been at Watkins Glen. Chassis GTP2 was now numbered #22, and GTP1 carried #23. The cars qualified 20th (#22) and 24th (#23), finding the long straights to be a disadvantage. During the race the #22 car encountered a fuel starvation problem early on, which slowed the car dramatically.

Number 23 would suffer a wheel bearing failure two hours later, resulting in a costly 3-hour repair. The car was disqualified by the ACO after six hours of running for not completing a sufficient amount of race distance. The limping #22 did not last much longer, as Thompson crashed it at Indianapolis corner when the wastegate was stuck open once again.

Le Mans, 1968.

Le Mans, 1968.

After the high profile disappointment at Le Mans, Howmet Corporation deemed campaigning the cars any further too expensive. However, not wanting to waste their publicity potential, they ordered a land speed record breaking version of chassis GTP2. The car was subsequently developed into a low-line roadster to minimize drag. Now named TX Mk.II, it managed to set 6 FIA-recognized speed records for turbine powered cars at Talladega Superspeedway in 1970.

The TX Mark II land speed racer during testing.

The TX Mark II land speed racer during testing.

The Howmet TX was a product of an excessively optimistic can-do era in American history. Fueled by the Jet Age sentiment of endless possibility, it tried to totally reinvent the sportscar in the most radical way possible.

The new and exciting technology it used was not without faults however, frequently causing spectacular fires and crashes. But on the rare occasions the package did work, it proved to be blisteringly quick. Its amazing speed still made the TX the first and only gas turbine powered car to win a race.