The Howmet TX (Turbine eXperimental) was an American
sports prototype
A sports prototype, sometimes referred to as simply a prototype, is a type of race car that is used in the highest-level categories of sports car racing. These purpose-built racing cars, unlike street-legal and production-based racing cars, are n ...
racing car
Auto racing (also known as car racing, motor racing, or automobile racing) is a motorsport involving the racing of automobiles for competition.
Auto racing has existed since the invention of the automobile. Races of various sorts were organise ...
designed in 1968 to test the competitive use of a
gas turbine
A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...
engine in
sports car racing
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 ...
. Planned by racing driver Ray Heppenstall, the TX combined a
chassis
A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...
built by McKee Engineering, turbine engines leased from
Continental Aviation & Engineering, and financial backing and materials from the
Howmet Corporation.
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,
earning two
Sports Car Club of America
The Sports Car Club of America (SCCA) is a non-profit American automobile club and sanctioning body supporting road racing, rallying, and autocross in the United States. Formed in 1944, it runs many programs for both amateur and professional r ...
(SCCA) race victories and two qualifying sprint victories during its only year of competition.
The TX later set six
Fédération Internationale de l'Automobile
The Fédération Internationale de l'Automobile (FIA; en, International Automobile Federation) is an association established on 20 June 1904 to represent the interests of motoring organisations and motor car users. It is the governing body for ...
(FIA)
land speed record
The land speed record (or absolute land speed record) is the highest speed achieved by a person using a vehicle on land. There is no single body for validation and regulation; in practice the Category C ("Special Vehicles") flying start regula ...
s for turbines after being retired from racing.
Development
Interest in the use of
gas turbine
A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...
s as an alternative to the
piston engine
A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...
had been gaining support in the automobile industry during the 1960s.
Chrysler
Stellantis North America (officially FCA US and formerly Chrysler ()) is one of the " Big Three" automobile manufacturers in the United States, headquartered in Auburn Hills, Michigan. It is the American subsidiary of the multinational automoti ...
had begun testing in the 1950s and began leasing their
Turbine Car to the public in 1963,
while British manufacturer
Rover
Rover may refer to:
People
* Constance Rover (1910–2005), English historian
* Jolanda de Rover (born 1963), Dutch swimmer
* Rover Thomas (c. 1920–1998), Indigenous Australian artist
Places
* Rover, Arkansas, US
* Rover, Missouri, US
* ...
and racing team
BRM
British Racing Motors (BRM) was a British Formula One motor racing team. Founded in 1945 and based in the market town of Bourne in Lincolnshire, it participated from 1951 to 1977, competing in 197 grands prix and winning seventeen. BRM wo ...
combined to build a racing car for the
24 Hours of Le Mans
The 24 Hours of Le Mans (french: link=no, 24 Heures du Mans) is an endurance-focused Sports car racing, sports car race held annually near the town of Le Mans, France. It is the world's oldest active Endurance racing (motorsport), endurance r ...
in and .
Both cars showed reliability but were unable to win over the public or to win at Le Mans respectively.
By 1967, team owner and car developer
Andy Granatelli
Anthony "Andy" Granatelli (March 18, 1923 – December 29, 2013) was an American businessman, most prominent as the CEO of STP as well as a major figure in automobile racing events.
Granatelli was born in Dallas, Texas. Along with his broth ...
had created the
STP-Paxton Turbocar
The STP-Paxton Turbocar was an American racing car, designed by Ken Wallis as the STP entry in the Indianapolis 500. Rufus Parnell, who raced under the name "Parnelli Jones," drove it in the 1967 event. After leading for much of the race, a transm ...
for the
Indianapolis 500
The Indianapolis 500, formally known as the Indianapolis 500-Mile Race, and commonly called the Indy 500, is an annual automobile race held at Indianapolis Motor Speedway (IMS) in Speedway, Indiana, United States, an enclave suburb of Indi ...
. The car nearly won the race driven by
Parnelli Jones
Rufus Parnell Jones (born August 12, 1933) is an American former professional racing driver and racing team owner. He is notable for his accomplishments while competing in the Indianapolis 500 and the Baja 1000 desert race. In 1962, he became the ...
, but suffered a mechanical failure after leading over two-thirds of the event.
A similar attempt with a
Lotus 56
The Lotus 56 was a gas turbine-powered four-wheel-driven racing car, designed by Maurice Philippe as Team Lotus's STP-backed entry in the 1968 Indianapolis 500. All three cars entered retired from the race, Joe Leonard's car expiring while lead ...
in 1968 also led to retirement after showing winning potential.
![Howmet TX 2 Front](https://upload.wikimedia.org/wikipedia/commons/0/06/Howmet_TX_2_Front.jpg)
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
The Rover-BRM was a prototype gas turbine-powered racing car, jointly developed in the early 1960s by the British companies Rover and British Racing Motors (BRM). The car is part of the collection at the British Motor Museum.
Rover had already ...
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
The Allison Engine Company was an American aircraft engine manufacturer. Shortly after the death of James A. Allison, James Allison in 1929 the company was purchased by the Fisher Body, Fisher brothers. Fisher sold the company to General Motors, ...
and later to
Williams Research.
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.
Chassis
Heppenstall began the project by purchasing a
Cooper
Cooper, Cooper's, Coopers and similar may refer to:
* Cooper (profession), a maker of wooden casks and other staved vessels
Arts and entertainment
* Cooper (producers), alias of Dutch producers Klubbheads
* Cooper (video game character), in ...
Monaco sports car, but later decided it was not the best choice for a turbine and the car was sold off.
Bob McKee, owner of McKee Engineering, was then contracted by Heppenstall to build two cars brand new. The first
space frame
In architecture and structural engineering, a space frame or space structure ( 3D truss) is a rigid, lightweight, truss-like structure constructed from interlocking struts in a geometric pattern. Space frames can be used to span large areas with ...
chassis was actually built from an older McKee car initially built for the
Can Am
The Canadian-American Challenge Cup, or Can-Am, was an SCCA/ CASC sports car racing series from 1966 to 1987.
History
Can-Am started out as a race series for group 7 sports racers with two races in Canada (''Can'') and four races in the United ...
series in 1966, but adapted to house the turbine engine.
The second car #GTP2 was built from scratch, allowing it to be purposely designed around the use of a turbine engine, including a chassis longer.
The chassis were known as the Mk.9 to McKee, but only ever raced as turbines under the Howmet TX guise.
The Mk.9 was designed around the
FIA
FIA is the Fédération Internationale de l'Automobile (English: International Automobile Federation), the world's governing body for all forms of motor sport where four or more wheels are used.
Fia or FIA may also refer to: People
* Fia Backst ...
's
Group 6 Group 6 may refer to:
*Group 6 element, chemical element classification
*Group 6 (racing), FIA classification for sports car racing
*Group 6 Rugby League
The Macarthur Division Rugby League is a senior Rugby league competition in New South Wale ...
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 door
In the automotive industry, a gull-wing door, also known as a falcon-wing door or an up-door, is a car door that is hinged at the roof rather than the side, as pioneered by Mercedes-Benz 300 SL, first as a race car in 1952 ( W194), and then a ...
s was designed by Bob McKee to shroud the
mid-engine layout. Standard
double wishbone suspension
A double wishbone suspension is an independent suspension design for automobiles using two (occasionally parallel) wishbone-shaped arms to locate the wheel. Each wishbone or arm has two mounting points to the chassis and one joint at the knuckle ...
with
coil spring
A selection of conical coil springs
The most common type of spring is the coil spring, which is made out of a long piece of metal that is wound around itself.
Coil springs were in use in Roman times, evidence of this can be found in bronze Fib ...
s were used with
disc brake
A disc brake is a type of brake that uses the calipers to squeeze pairs of pads against a disc or a "rotor" to create friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hol ...
s on each wheel. A fuel tank was placed between the cockpit and turbine, housing
Jet A
Jet fuel or aviation turbine fuel (ATF, also abbreviated avtur) is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is colorless to straw-colored in appearance. The most commonly used fuels for commercial a ...
fuel.
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.
The loaned turbines weighed and were able to provide and of torque.
A maximum of 57,000
rpm
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines.
Standards
ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...
was able to be reached.
![Howmet TX 2 Exhaust](https://upload.wikimedia.org/wikipedia/commons/2/2d/Howmet_TX_2_Exhaust.jpg)
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.
The turbine itself used two large exhaust pipes. However, a third pipe was situated off-center for use with a
wastegate
A wastegate is a valve that controls the flow of exhaust gases to the turbine wheel in a turbocharged engine system.Robson, D. (2018). Aircraft General Knowledge. Aviation Theory Centre Pty Ltd. .
Diversion of exhaust gases regulates the turbine ...
. 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.
Although turbines cannot have their
displacement
Displacement may refer to:
Physical sciences
Mathematics and Physics
*Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...
measured in the same way as a piston engine, the FIA used an equivalence formula to determine the Continental TS325-1's displacement of ,
although Heppenstall has since admitted that the engine was actually above the three litre limit.
This allowed the Howmet to compete in the Prototype Under 3000 cc category of the Group 6 formula.
Racing history
Following completion of the two Howmet TXs, the cars were brought to the
24 Hours of Daytona
The 24 Hours of Daytona, also known as the Rolex 24 At Daytona for sponsorship reasons, is a 24-hour sports car endurance race held annually at Daytona International Speedway in Daytona Beach, Florida. It is run on the Sports Car Course layou ...
, 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.
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.
The driving team of Heppenstall,
Dick Thompson, and Ed Lowther qualified with a lap time seventh fastest overall.
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.
By the
12 Hours of Sebring
The 12 Hours of Sebring is an annual motorsport endurance race for sports cars held at Sebring International Raceway, on the site of the former Hendricks Army Airfield World War II air base in Sebring, Florida, US. The event is the second round ...
a few weeks later, the TX was able to improve its pace, this time qualifying third, only a second behind a
Porsche 907
The Porsche 907 is a sportscar racing prototype built by Porsche in 1967 and 1968.
1967
The 907 was introduced at the 1967 24 Hours of Le Mans. Following a suggestion by Ferdinand Piëch, the position of the driver was moved from the tradition ...
and a
Ford GT40
The Ford GT40 is a high-performance endurance racing car commissioned by the Ford Motor Company. It grew out of the "Ford GT" (for Grand Touring) project, an effort to compete in European long-distance sports car races, against Ferrari, which wo ...
.
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.
Following Sebring, the International Championship returned to Europe, and the Howmet team followed. They entered the
BOAC 500 The Brands Hatch 1000 km was an endurance sports car event that was part of the World Sportscar Championship for varying years from 1967 until 1989. Originally a six-hour race running under the name BOAC 500, the event was eventually extended ...
at
Brands Hatch
Brands Hatch is a motor racing circuit in West Kingsdown, Kent, England, United Kingdom. Originally used as a grasstrack motorcycle circuit on farmland, it hosted 12 runnings of the British Grand Prix between 1964 and 1986 and currently host ...
. Wastegate problems once again caused the car to crash, this time after only seven laps.
Staying in England, the Howmet team entered a national sprint race at
Oulton Park
Oulton Park is a hard surfaced track used for motor racing, close to the village of Little Budworth, Cheshire, England. It is about from Winsford, from Chester city centre, from Northwich and from Warrington, with a nearby rail connection a ...
for English driver
Hugh Dibley. The failure of a starter motor during a
pit stop
In motorsports, a pit stop is a pause for refuelling, new tyres, repairs, mechanical adjustments, a driver change, as a penalty, or any combination of the above. These stops occur in an area called the pits, most commonly accessed via a pit la ...
, however, once again denied the TX the possibility of finishing the hour-long event.
![1968HowmetTX](https://upload.wikimedia.org/wikipedia/commons/7/76/1968HowmetTX.jpg)
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
New Cumberland is a city in and the county seat of Hancock County, West Virginia, Hancock County, West Virginia, United States, along the Ohio River. The population was 1,020 as of the 2020 United States Census, 2020 census. It is part of the Weir ...
. Heppenstall drove the car to a second-place finish,
setting a new lap record for the circuit.
Following a retirement in Michigan, the TX next arrived at the Heart of Dixie event in
Huntsville, Alabama
Huntsville is a city in Madison County, Limestone County, and Morgan County, Alabama, United States. It is the county seat of Madison County. Located in the Appalachian region of northern Alabama, Huntsville is the most populous city in t ...
. 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
In a motorsports race, the pole position is usually the best and "statistically the most advantageous" starting position on the track. The pole position is usually earned by the driver with the best qualifying times in the trials before the rac ...
for the main event.
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.
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.
Feeling that the TX was now capable of taking on European entries, both TXs were entered in the
6 Hours of Watkins Glen
The Six Hours of Watkins Glen (currently sponsored as the Sahlen's Six Hours of The Glen) is a sports car endurance race held annually at Watkins Glen International in Watkins Glen, New York. The race dates from 1948, and has been a part of the ...
, another round of the International Championship. Hugh Dibley and newcomer
Bob Tullius
Robert Charles "Bob" Tullius was born 7 December 1930 in Rochester, New York. He is best known as a race car driver and racing team owner.
Early years
Tullius considered a career in teaching after graduating from high school. He served a term in ...
were entered in the first car, while Heppenstall and Thompson shared the second. The cars qualified eighth and ninth fastest.
Following early accidents by the factory
Porsche
Dr. Ing. h.c. F. Porsche AG, usually shortened to Porsche (; see #Pronunciation, below), is a German automobile manufacturer specializing in high-performance sports cars, SUVs and sedans, headquartered in Stuttgart, Baden-Württemberg, Germany ...
s the TX cars were running third and fourth overall.
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.
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.
After the Watkins Glen success, the two cars were prepared for an attempt at the
24 Hours of Le Mans
The 24 Hours of Le Mans (french: link=no, 24 Heures du Mans) is an endurance-focused Sports car racing, sports car race held annually near the town of Le Mans, France. It is the world's oldest active Endurance racing (motorsport), endurance r ...
, which had been postponed until September. French aluminium company
Pechiney
Pechiney SA was a major aluminium conglomerate based in France. The company was acquired in 2003 by the Alcan Corporation, headquartered in Canada. In 2007, Alcan itself was taken over by mining giant Rio Tinto Alcan.
Prior to its acquisition, ...
sponsored the team's bid at the 24 hours.
The same drivers were assigned to the cars, but their qualifying performance at the
Circuit de la Sarthe
The Circuit des 24 Heures du Mans, also known as Circuit de la Sarthe (after the 1906 French Grand Prix triangle circuit) located in Le Mans, Sarthe, France, is a semi-permanent motorsport race course, chiefly known as the venue for the 24 Hou ...
was hampered by the long straights. Twentieth fastest was the best performance from the two cars.
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.
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.
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.
However, Howmet felt that the program was not providing adequate promotion for the company and decided to discontinue it.
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 , the car was able to make attempts at two classes of records thanks to the addition or subtraction of ballast.
On a road next to
Talladega Superspeedway
Talladega Superspeedway, nicknamed “'Dega”, and formerly named Alabama International Motor Speedway (AIMS) from 1969 to 1989, is a motorsports complex located north of Talladega, Alabama. It is located on the former Anniston Air Force Base ...
in August 1970, Heppenstall drove the TX Mk.II to six records recognized by the
FIA
FIA is the Fédération Internationale de l'Automobile (English: International Automobile Federation), the world's governing body for all forms of motor sport where four or more wheels are used.
Fia or FIA may also refer to: People
* Fia Backst ...
,
with the timing recorded by the new
International Motor Sports Association
The International Motor Sports Association (IMSA) is a North American sports car racing sanctioning body based in Daytona Beach, Florida under the jurisdiction of the ACCUS arm of the FIA. It was started by John Bishop, a former executive direc ...
(IMSA).
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.
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.
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
Amelia Island is a part of the Sea Islands chain that stretches along the East Coast of the United States from South Carolina to Florida; it is the southernmost of the Sea Islands, and the northernmost of the barrier islands on Florida's Atlantic ...
Concours d'Elegance
''Concours d'Elegance'' ( French: ''concours d'élégance'') is a term of French origin that means a "competition of elegance" and refers to an event where prestigious vehicles are displayed and judged. It dates back to 17th-century France, whe ...
.
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
Allison may refer to:
People
* Allison (given name)
* Allison (surname) (includes a list of people with this name)
* Eugene Allison Smith (1922-1980), American politician and farmer
Companies
* Allison Engine Company, American aircraft engine ...
250C18 turbine was installed.
Chuck Haines participated three times at the
Goodwood Festival of Speed
The Goodwood Festival of Speed is an annual motorsports festival featuring modern and historic motor racing vehicles taking part in a hillclimbing, hill climb and other events, held in the grounds of Goodwood House, West Sussex, England, in l ...
. 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
The Le Mans Classic is a biennial historic racing, vintage sports car racing, sports car event held on the grounds of the 24 Hours of Le Mans, created by Peter Auto and Richard Mille, and associated with Automobile Club de l'Ouest (ACO). It began ...
event in 2008, 2010 and 2012, the Classic Endurance Racing series from 2009 to 2012, as well as the
Goodwood Festival of Speed
The Goodwood Festival of Speed is an annual motorsports festival featuring modern and historic motor racing vehicles taking part in a hillclimbing, hill climb and other events, held in the grounds of Goodwood House, West Sussex, England, in l ...
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.
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
Historic motorsport or vintage motorsport, is motorsport with vehicles limited to a particular era. Only safety precautions are modernized in these hobbyist races. A historical event can be of various types of motorsport disciplines, from road ...
events, including the 2007 Goodwood Festival of Speed.
Bob McKee built #GTP4 for Xavier Micheron , #GTP4 has participated in many events after completion around 2017-2018 including Classic LeMans 2018
References
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
- Recent history of the Howmet TX GTP2
{{Good article
Sports prototypes
Cars powered by gas turbines