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 gas turbines as an alternative to the piston engine had been gaining support in the automobile industry during the 1960s. Chrysler had begun testing in the 1950s and began leasing their Turbine Car to the public in 1963,[citation needed] while British manufacturer Rover and racing team BRM combined to build a racing car for the 24 Hours of Le Mans in 1963 and 1965.[4] Both cars showed reliability but were unable to win over the public or to win at Le Mans respectively.[5] By 1967, team owner and car developer Andy Granatelli had created the STP-Paxton Turbocar for the Indianapolis 500. The car nearly won the race driven by Parnelli Jones, but suffered a mechanical failure after leading over two-thirds of the event.[6] A similar attempt with a Lotus 56 in 1968 also led to retirement after showing winning potential.[5]
The Howmet TX was built on the McKee Mk.9 chassis. This is the first example of two built in period.
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 Rover-BRM had failed several years before. Heppenstall felt that a more simplified design for the chassis could make a turbine-powered car more competitive. Heppenstall originally proposed the car to Allison Engine Company and later to Williams Research.[7] He eventually turned to fellow racer Tom Fleming for aid. Fleming was at the time vice-president of Howmet Corporation, which provided castings for turbines in the aerospace industry. Heppenstall and Fleming were able to convince Howmet that their backing of a competitive and unique sports car could promote public awareness of the company. Howmet agreed to fund the project, lending their name to the car.[2]
Chassis
Heppenstall began the project by purchasing a Cooper Monaco sports car, but later decided it was not the best choice for a turbine and the car was sold off.[7] Bob McKee, owner of McKee Engineering, was then contracted by Heppenstall to build two cars brand new. The first space frame chassis was actually built from an older McKee car initially built for the Can Am series in 1966, but adapted to house the turbine engine.[5][8] The second car #GTP2 was built from scratch, allowing it to be purposely designed around the use of a turbine engine, including a chassis 2.25 inches (57mm) longer.[2] The chassis were known as the Mk.9 to McKee, but only ever raced as turbines under the Howmet TX guise.[8]
The Mk.9 was designed around the FIA's Group 6 regulations for sports prototypes, allowing for a completely custom mid-engine layout that was only limited in terms of engine sizes available to competitors. Closed cockpit bodywork with gullwing doors was designed by Bob McKee to shroud the mid-engine layout. Standard double wishbone suspension with coil springs were used with disc brakes on each wheel. A 32-US-gallon (120L) fuel tank was placed between the cockpit and turbine, housing Jet A fuel.[5]
Turbine
The turbines to power the two Howmet TXs were leased from Continental Aviation & Engineering. The TS325-1 gas turbines were prototypes from an aborted bid for a military helicopter contract which Continental was not putting to use at the time.[9] The loaned turbines weighed 170 pounds (77kg) and were able to provide 350bhp (260kW) and 650lbf⋅ft (880N⋅m) of torque.[2] A maximum of 57,000rpm was able to be reached.[9]
The exhaust pipes for the original Continental turbine. The smaller pipe at the back is for the turbine's wastegate.
A two-stage setup used an internal power turbine to drive the rear wheels through the use of reduction gearing. Due to the wide variable output of the turbine and the high level of torque, a standard gearbox was not necessary, leaving the Howmet TX with only a single gearing speed. However, the gearing ratios were able to be quickly changed in the differential, allowing the car to be adapted to various circuits. Due to the use of a single-speed transmission, there was no gearing for reverse. Although Heppenstall initially wished to do without reverse, the FIA mandated its use and a small electric motor powered by the turbine was installed, allowing the car to move in reverse.[2][7]
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][7]
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 (181cuin),[9] although Heppenstall has since admitted that the engine was actually above the three litre limit.[7] This allowed the Howmet to compete in the Prototype Under 3000cc category of the Group 6 formula.[5]
Racing history
Following completion of the two Howmet TXs, the cars were brought to the 24 Hours of Daytona, the opening round of the 1968 International Championship for Makes. Before even entering competition the TX earned attention, and was featured prominently on the cover of the race program.[10] Although both cars were in attendance, only the newer (#GTP2) of the two was entered in the race; the other car (#GTP1) was kept as a spare.[2] The driving team of Heppenstall, Dick Thompson, and Ed Lowther qualified with a lap time seventh fastest overall.[11] Several competitors made early refueling stops allowing the Howmet to improve to third place but on lap 34 the turbine wastegate failed to reopen, giving the driver too much power for the corner he was in. The car spun and hit a barrier, forcing the team to retire.[5]
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.[11] 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][7][12] 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.[5][13] 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][5] 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.[5]
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][5] 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.[11] Following early accidents by the factory Porsches the TX cars were running third and fourth overall.[5][11] 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.[5]
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.[7] 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.[11]
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.[5][11] The remaining fuel-starved TX did not last much longer as Thompson crashed in the Indianapolis corner.
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.[7] However, Howmet felt that the program was not providing adequate promotion for the company and decided to discontinue it.[2][5]
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 (2,200lb), the car was able to make attempts at two classes of records thanks to the addition or subtraction of ballast.[9]
An Allison 250C18 turbine installed in chassis #GTP3.
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.[9] Heppenstall eventually sold the two chassis.
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 IslandConcours d'Elegance.[14]
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.[8][9] Chuck Haines participated three times at the Goodwood Festival of Speed. In 2006, it was later sold to Xavier Micheron who adapted the wastegate system to the Allison turbine. #GTP2 has since participated in the Le Mans Classic event in 2008, 2010 and 2012, the Classic Endurance Racing series from 2009 to 2012, as well as the Goodwood Festival of Speed in 2009. It is now a part of the ROFGO collection.
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][8] 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.[15] Bob McKee built #GTP4 for Xavier Micheron , #GTP4 has participated in many events after completion around 2017-2018 including Classic LeMans 2018
Related Research Articles
Sports car racing is a form of motorsport road racing which utilises sports cars that have two seats and enclosed wheels. They may be purpose-built prototypes or grand tourers based on road-going models. Broadly speaking, sports car racing is one of the main types of circuit auto racing, alongside open-wheel single-seater racing, touring car racing and stock car racing. Sports car races are often, though not always, endurance races that are run over particularly long distances or large amounts of time, resulting in a larger emphasis on the reliability and efficiency of the car and its drivers as opposed to outright car performance or driver skills. The FIA World Endurance Championship is an example of a sports car racing series.
The Porsche 961 was a racing car built by Porsche and based on their 959 sports car. It was intended for Group B sports car racing, complementing the purpose-built 956 and 962C which ran Group C in the World Sports-Prototype Championship. The 961 project was short-lived, running only three races and seeing the construction of only one car. Plans to sell the car to customers were scrapped when the Group B class was canceled.
The Porsche 935 was a race car developed and manufactured by German automaker Porsche. Introduced in 1976 as the factory racing version of the 911 (930) Turbo and prepared for FIA-Group 5 rules, it was an evolution of the Carrera RSR 2.1 turbo prototype, the second place overall finisher in the 1974 24 Hours of Le Mans.
The Ferrari 333 SP is a sports prototype race car that was built by Italian race car manufacturer Dallara and later Michelotto to compete in the World Sports Car championship for Ferrari. Unveiled at the end of 1993, at the behest of amateur racer Giampiero Moretti, the 333 SP marked Ferrari's official return to sports car racing after a 20-year absence. The car was built to compete in the IMSA's new WSC class, which replaced the previous GTP cars.
The Porsche 962 is a sports-prototype racing car built by Porsche as a replacement for the 956 and designed mainly to comply with IMSA's GTP regulations, although it would later compete in the European Group C formula as the 956 had. The 962 was introduced at the end of 1984, from which it quickly became successful through private owners while having a remarkably long-lived career, with some examples still proving competitive into the mid-1990s. The vehicle was later replaced by the Porsche WSC-95.
The 1968 24 Hours of Le Mans was the 36th Grand Prix of Endurance, and took place on 28 and 29 September 1968 on the Circuit de la Sarthe, in Le Mans, France.
Joest Racing is a sports car racing team that was established in 1978 by former Porsche works racer Reinhold Joest. Their headquarters are in Wald-Michelbach, Germany.
The 1968 World Sportscar Championship season was the 16th season of FIA World Sportscar Championship racing and featured the 1968 International Championship for Makes and the 1968 International Cup for GT Cars. The former was contested by Group 6 Sports Prototypes, Group 4 Sports Cars and Group 3 Grand Touring Cars and the later by Group 3 Grand Touring Cars only. The two titles were decided over a ten race series which ran from 3 February 1968 to 29 September 1968, but one race was only worth half points, and only the five best results were counted.
The Panoz Esperante GTR-1 was a race car developed by Panoz Auto Development and Reynard Motorsport for grand tourer endurance racing in 1997. Although named after the Panoz Esperante roadster, the GTR-1 actually bore no mechanical relation to the production Esperante, instead sharing only minor styling points. Only two road-legal GTR-1s were built to meet homologation requirements set forth by the ruling bodies which the racing cars ran under.
Porsche has been successful in many branches of motorsport of which most have been in long-distance races.
IMSA GT was a sports car racing series organized by International Motor Sports Association. Races took place primarily in the United States, and occasionally in Canada.
The Chevrolet Corvette GTP was an American Grand Touring Prototype-class sports prototype racing car which successfully participated in the IMSA Camel GT from 1984 until 1989. The car was professionally fielded in competition as General Motors' Chevrolet Corvette C4 official factory team effort in the IMSA GTP class.
The Nissan GTP ZX-Turbo was a series of racing cars developed for Nissan Motors by Electramotive Engineering to compete in the IMSA GT Championship. Running from 1985 to 1990, they were known for being the first car to defeat the Porsche 962 which had dominated IMSA's premiere GTP category. This led to Nissan winning the constructor's championship and 12 Hours of Sebring in 1989 and 1990. During 1990, the GTP ZX-Turbo was replaced by the newer NPT-90.
The Nissan NPT-90 was a racing car developed in 1990 for Nissan Motors by Nissan Performance Technology Incorporated (NPTI), formerly known as Electramotive Engineering. It was a replacement for the highly successful GTP ZX-Turbo that had won the IMSA GT Championship in 1989. The NPT-90 would go on to win the championship in 1990 and 1991 before being retired by Nissan at the end of the 1992 season.
The Mazda RX-792P is a sports prototype racing car built for the IMSA GT Championship's GTP category for Mazda. Its career was short lived, with only two cars running in 1992 before the project was abandoned.
The 1984 Sandown 1000 was an endurance motor race staged at the Sandown Raceway in Victoria, Australia on 2 December 1984. It was the eleventh and final round of the 1984 FIA World Endurance Championship and was the first FIA World Championship race to be held in Australia. It was to be the first of a three-year contract to race at Sandown, though the final two years would be cancelled.
The Eagle HF89 and its evolution, the Eagle HF90, is a racing car built and entered by Dan Gurney's All American Racers team, for the IMSA GT Championship. It was raced from 1989 until 1991 in IMSA's premier sports-car racing category, the GTP division. The design was also sometimes called the Eagle MkII.
The Intrepid RM-1 is a sports prototype racing car designed in 1991 by Bob and Bill Riley and built by Pratt & Miller to IMSA GTP specifications. Powered by a Chevrolet V8 engine, it was campaigned variously by Jim Miller, Prototype Technology Group and Wayne Taylor in the IMSA Camel GT from 1991 through 1993. Though it won only one race in its three seasons of competition, the shovel-nosed Intrepid was notable for the extreme—and at one point, disastrous—levels of downforce it generated, giving it the highest cornering speeds of any prototype of its era. The car's development was set back by a devastating 1991 crash at Watkins Glen that critically injured driver Tommy Kendall, and the program never fully recovered.
The Mazda GTP is an IMSA GTP race car that was built by Pierre Honegger in 1981. Based on a Mazda RX-7, the car initially competed in the GTX category as the Mazda RX-7 GTP, before it was rebuilt for the IMSA GTP category in 1983. Throughout its career, the car used a Mazda 13B Wankel rotary engine, similar to that used in the production RX-7s. Although the rotary-engined sports prototypes generally had a reputation of being very reliable, the Mazda GTP frequently failed to finish races, and was never able to better the eighth place achieved at the 1983 24 Hours of Daytona. In 1986, one car was purchased by Erie Scientific Racing, and rebuilt to become the Badger BB. This car was no more successful or reliable than its predecessor, and was last used in 1989, by which point it was owned by Jack Engelhardt. The other car, meanwhile, was rebuilt by Honegger into the Denali Speedcar, which was used with moderate success in 1986 and 1987.
The Rebellion R-One is a sports prototype racing car built by French constructor Oreca on behalf of Swiss-based team Rebellion Racing. It is designed to meet the 2014 LMP1-L regulations for Le Mans Prototypes in the FIA World Endurance Championship as well as at the 24 Hours of Le Mans, and replaces the Lola B12/60 chassis. The first two R-Ones debuted at the 2014 6 Hours of Spa-Francorchamps, round two of the FIA World Endurance Championship. The Rebellion R-One shares the same monocoque as the Oreca 05, and the Oreca 07.
References
1 2 3 4 5 Clark, Eric (September 1968). "Howmet TX". Model Cars. Model & Allied Publications. p.439.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
Ray Heppenstall
Hugh Dibley 
