Howmet TX
Debut | 1968 24 Hours of Daytona | ||||||||
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Last season | 1968 | ||||||||
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Constructors' Championships | 0 | ||||||||
Drivers' Championships | 0 |
The Howmet TX (Turbine eXperimental) is an American
Although not the first attempt at using a turbine powerplant in auto racing, the Howmet TX was the first and is still the only turbine to win a race,[2] earning two Sports Car Club of America (SCCA) race victories and two qualifying sprint victories during its only year of competition.[3] The TX later set six Fédération Internationale de l'Automobile (FIA) land speed records for turbines after being retired from racing.[2]
Development
Interest in the use of

At the same time as Granatelli's turbine debut at Indy, racer Ray Heppenstall began to conceive a design for his own sports car to make use of a gas turbine, improving in some areas where the
Chassis
Heppenstall began the project by purchasing a
The Mk.9 was designed around the
Turbine
The turbines to power the two Howmet TXs were leased from
A two-stage setup used an internal power turbine to drive the rear wheels through the use of
The turbine itself used two large exhaust pipes. However, a third pipe was situated off-center for use with a wastegate. The wastegate was designed to eliminate the lag between the driver pressing the accelerator and the turbine increasing its revolutions. Once the turbine was at its maximum revolutions, the wastegate helped regulate the flow of hot gas from the core to the power-turbine, thus increasing or decreasing the power output to the gearbox far quicker than the core could adjust mass-flow by itself.[2][8]
Although turbines cannot have their displacement measured in the same way as a piston engine, the FIA used an equivalence formula to determine the Continental TS325-1's displacement of 2,960 cubic centimetres (181 cu in),[10] although Heppenstall has since admitted that the engine was actually above the three litre limit.[8] This allowed the Howmet to compete in the Prototype Under 3000 cc category of the Group 6 formula.[6]
Racing history
Following completion of the two Howmet TXs, the cars were brought to the
By the 12 Hours of Sebring a few weeks later, the TX was able to improve its pace, this time qualifying third, only a second behind a Porsche 907 and a Ford GT40.[12] The turbine ran reliably at first but, as the race continued, debris damaged the turbine and caused it to shake loose from its mounts. The TX was eventually retired after six hours.[2][8][13] Following Sebring, the International Championship returned to Europe, and the Howmet team followed. They entered the BOAC 500 at Brands Hatch. Wastegate problems once again caused the car to crash, this time after only seven laps.[6][14] Staying in England, the Howmet team entered a national sprint race at Oulton Park for English driver Hugh Dibley. The failure of a starter motor during a pit stop, however, once again denied the TX the possibility of finishing the hour-long event.[2]

The TX returned to the United States to contest the SCCA National Championship rather than stay in Europe for the remainder of the International Championship. Closer to home, the problems with the experimental TX were able to be overcome as the car finished its first race, the Vandergraft Trophy in New Cumberland, West Virginia. Heppenstall drove the car to a second-place finish,[3][6] setting a new lap record for the circuit.[2] Following a retirement in Michigan, the TX next arrived at the Heart of Dixie event in Huntsville, Alabama. A short sprint race was held on the day prior to the main race in order to determine the starting order of the field. The Howmet TX was able to earn victory in the sprint, allowing it to start on pole position for the main event.[3] From there the TX dominated the event and earned another win. These two victories marked the first-ever wins by a turbine-powered car in a racing event.[6]
With the first victory earned by the Howmet TX, Heppenstall was once again joined by Dick Thompson for the Marlboro 300. Once again the car won the short qualifying race to earn pole position and went on to lead every lap of the main event, winning by an eleven-lap margin.[3][6] Feeling that the TX was now capable of taking on European entries, both TXs were entered in the 6 Hours of Watkins Glen, another round of the International Championship. Hugh Dibley and newcomer Bob Tullius were entered in the first car, while Heppenstall and Thompson shared the second. The cars qualified eighth and ninth fastest.[12] Following early accidents by the factory Porsches the TX cars were running third and fourth overall.[6][12] The Dibley and Tullius car suffered a transmission problem in the closing hour requiring the car to crawl around the circuit until the end of the race.[2] The other entry remained on pace until the end, finishing on the podium overall and was the highest finisher in its class. The podium earned Howmet four points towards the International Championship.[6]
After the Watkins Glen success, the two cars were prepared for an attempt at the 24 Hours of Le Mans, which had been postponed until September. French aluminium company Pechiney sponsored the team's bid at the 24 hours.[8] The same drivers were assigned to the cars, but their qualifying performance at the Circuit de la Sarthe was hampered by the long straights. Twentieth fastest was the best performance from the two cars.[12]
For the race itself, mechanical problems appeared early as Thompson's car suffered after only three laps. The fuel system was not providing enough Jet A to the turbine to allow it to produce its full power output, meaning the car had to limp down the circuit's long straights.[2] While that car continued at a slowed pace, the other suffered a wheel bearing failure two hours later, requiring a lengthy three-hour repair. By the sixth hour of the event the car was disqualified by race officials, having covered an insufficient distance of only 60 laps.[6][12] The remaining fuel-starved TX did not last much longer as Thompson crashed in the Indianapolis corner.[15]
With the 1968 season over, Heppenstall planned for the following year, including the development of a new multi-gear transmission to replace the single speed unit.[8] However, Howmet felt that the program was not providing adequate promotion for the company and decided to discontinue it.[2][6]
Land speed records
Howmet decided in 1969 that although the racing program was too expensive to continue, the two cars it owned could still be put to promotional use. Heppenstall decided that he would attempt to repair the second TX chassis (#GTP2) to adapt new open-cockpit bodywork, earning it the name Howmet TX Mk.II. The new vehicle attempted to break world land speed records for turbine-powered cars. With the TX Mk.II weighing approximately 1,000 kilograms (2,200 lb), the car was able to make attempts at two classes of records thanks to the addition or subtraction of ballast.[10]
On a road next to
FIA Speed Records | ||||
---|---|---|---|---|
Class | Type | Time seconds |
Speed | |
km/h | mph | |||
Class 2 (over 500 kg, under 1000 kg) |
Standing start, ¼ mi | 11.83 | 122.41 | 76.06 |
Standing start, ½ km | 13.48 | 133.53 | 82.97 | |
Standing start, 1 km | 21.18 | 167.97 | 104.37 | |
Class 3 (over 1000 kg) |
Standing start, ¼ mi | 13.87 | 104.41 | 64.88 |
Standing start, ½ km | 15.74 | 114.35 | 71.05 | |
Standing start, 1 km | 23.92 | 150.50 | 93.52 |
Later use

In 1971, Howmet ended their promotional use of the two TX cars. The two chassis were sold to Ray Heppenstall for one dollar. However, because the two Continental turbines had been leased to Howmet, they had to be returned once the cars were no longer under Howmet's control.[10] Heppenstall eventually sold the two chassis.[15]
Chassis #GTP1 was bought by Jim Brucker and stored in his personal collection in California. On display, it featured a mock-up of the Continental turbine in the engine bay.[2] The car was bought in 2006 by Bruce Linsmeyer of Avon Aero and has been restored with an original Continental turbine. Following restoration, #GTP1 won the Sebring Trophy at the 2007 Amelia Island Concours d'Elegance.[16]
The second car, chassis #GTP2, was converted from its open-cockpit bodywork back into its original closed-cockpit design in a restoration carried out by McKee Engineering at the behest of new owner Chuck Haines. The restoration of Chassis #GTP2 was completed in July 1996. Original Continental turbines could not be obtained, so an Allison 250C18 turbine was installed.[9][10] During Haines' ownership of chassis #GTP2, Bob McKee completed a spare frame, known as #GTP3, to original specification for Haines. Again, due to the lack of a Continental turbine, an Allison unit was used instead.[2][9] The different powerplant required some redesign, as the exhaust was now vented out of the top of the engine cover instead of out the rear of the car. #GTP3 does not have the wastegate system. Haines has entered the car in historic motorsport events, including the 2007 Goodwood Festival of Speed.[17]
References
- ^ a b c d e Clark, Eric (September 1968). "Howmet TX". Model Cars. Model & Allied Publications. p. 439.
- ^ a b c d e f g h i j k l m n o p q r "The history of the Howmet TX turbine car of 1968, still the world's only turbine powered race winner". Pete Stowe's MotorSport History. 2006. Archived from the original on March 2, 2008. Retrieved 2008-03-07.
- ^ a b c d "US National Races 1968". World Sports Racing Prototypes. 2 October 2005. Archived from the original on 24 September 2008. Retrieved 2008-03-10.
- ^ Bedard, Patrick (May 1989). "Revisiting the Future with the 1963 Chrysler Turbine Car". Car and Driver. Retrieved 25 March 2025.
- ^ "The Rover Turbine Cars". The Rover Car Club of Auckland. Archived from the original on 2010-12-11. Retrieved 2008-06-16.
- ^ a b c d e f g h i j k l m n Mattijs Diepraam (19 May 2003). "The rise and fall of alternative power in motor racing - Swoosh and screech! - Part 1: Aircraft on asphalt". 8W. Archived from the original on 2021-02-10. Retrieved 2008-03-07.
- New York Times. Archivedfrom the original on 2014-08-10. Retrieved 2008-06-16.
- ^ a b c d e f g h "Transcripts: Ray Heppenstall". International Motor Racing Research Center. 10 July 2000. Archived from the original on 9 July 2008. Retrieved 2008-03-23.
- ^ a b c d "McKee chassis numbers". World Sports Racing Prototypes. 31 January 2006. Archived from the original on 20 October 2007. Retrieved 2008-03-07.
- ^ a b c d e f "1968 Howmet TX". Ultimatecarpages. 3 July 2006. Archived from the original on 2011-06-12. Retrieved 2008-04-08.
- ^ "Daytona 24 Hours 1968". Racing Sports Cars. 25 April 2006. Archived from the original on 2021-02-10. Retrieved 2008-04-08.
- ^ a b c d e f "International Championship for Makes 1968". World Sports Racing Prototypes. 2 October 2005. Archived from the original on 26 April 2008. Retrieved 2008-03-10.
- ^ "Sebring 12 Hours 1968". Racing Sports Cars. 28 September 2006. Archived from the original on 2021-02-10. Retrieved 2008-04-08.
- ^ "Brands Hatch 6 Hours 1968". Racing Sports Cars. 7 December 2005. Archived from the original on 2021-02-10. Retrieved 2008-04-08.
- ^ a b Hodges, Jared (14 December 2019). "The Howmet TX: A Brief History Of The Sportscar Turbine Age". BackRoads.com. Retrieved 25 March 2025.
- ^ "Howmet Turbine". Avon Aero, Inc. 2007. Archived from the original on 2008-03-02. Retrieved 2008-03-08.
- ^ "About Can-Am Cars". Can-Am Cars Ltd. Archived from the original on 2008-05-03. Retrieved 2008-06-13.
Notes
- The Howmet TX earned two main race wins. The two qualifying sprint wins are not counted toward its overall total.
External links
- endurance-series.com - Howmet TX article (in French)
- - Recent history of the Howmet TX GTP2