The Howmet TX: A Brief History Of The Sportscar Turbine Age



The 1960s saw many weird and wacky cars in the automotive world, but one stood out amongst the crowd: The Howmet TX, a turbine-powered Sportscar!

The TX was the brainchild of Ray Heppenstall and Bob McKee of McKee engineering, built on a chassis developed by McKee engineering and powered by a loaned Turbine Engine from Continental Aviation & Engineering. Heppenstall began to develop his idea for the TX after seeing the Rover-BRM driven by Graham Hill and Jackie Stewart at Le Mans in the early 60s. This was then followed with the STP-Paxton Turbocar which nearly won the infamous Indianapolis 500. The Turbocar was driven by Parnelli Jones, completing 482 miles of the 500 miles; retiring from the lead.

The TX used two turbines supplied by Continental, originally intended for use in a military helicopter until the contract was abandoned. Both turbines combined weighed just 77kg, with an output of 350bhp and 880Nm of torque! The max RPM? 57,000 RPM!

To reduce the time it takes to spool up the turbine, they used a wastegate to eliminate the lag from the turbine engines spooling up, resulting in an interesting three-exhaust layout at the rear.

Designed for the FIA’s Group 6 Sports Prototype regulations, the chassis was developed by Bob McKee and McKee Engineering with a mid-engined layout, using gullwing doors to shroud the Turbine mounted behind the driver. There was no suspension or brake trickery with this, just standard double wishbones and disc brakes on all four corners; but it wasn’t unusual for drivers to get on the throttle under braking to keep the car stable and keep the RPMs up due to the Turbine spool time.

Racing History

Howmet TX - 1968 12 Hours of Sebring

After completing two Howmet TX chassis, they were brought to the 24 Hours of Daytona in 1968. One was used for promotion prior to the race, with the other GTP2 Chassis running in the race, driven by Heppenstall himself, Dick Thompson and Ed Lowther. They qualified seventh fastest overall, eventually making their way to third place before the wastegate could not reopen, forcing too much power into a corner and causing the car to spin out and crash. The team returned to racing at the 12 Hours of Sebring, running a second behind a Porsche 907 and a Ford GT40, before again suffering wastegate failure causing a retirement.

A brief foray into Europe, the Howmet team entered the BOAC 500 at Brands Hatch but failing again due to a Wastegate after just seven laps. At the next round in Oulton Park, the team didn’t suffer a wastegate failure; instead having a starter motor failure during a pit stop causing them to retire.

They returned to the United States to compete in the SCCA National Championship instead of staying around in Europe for longer. Once they got on top of their issues, Ray Heppenstall drove the car to 2nd place at the Vandergraft Trophy in West Virginia, setting a new lap record in the process. A few rounds later after a previous retirement, the Howmet TX made it to the Heart of Dixie race in Alabama, earning pole position in a short sprint race for the main event. From pole position, the car ran well and comfortably dominated the race leading to the first-ever race win for a turbine-powered car!

Following on from their victory in Alabama, they entered the Howmet TX in the Marlboro 300, with Dick Thompson joining Ray Heppenstall once more to challenge the race. Winning the short qualifying sprint race, they once again lead every lap comfortably in the main event from pole position – taking another win for the Turbine engine.

A return to Europe was overdue, this time attempting to take on the mighty 24 Hours of Le Mans. Sponsored by Pechiney, a French aluminium company, they took two cars to Le Mans; the first driven by Ray Heppenstall and Dick Thompson, the second car driven by Hugh Dibley and Bob Tullius. Due to the long Mulsanne straight, they only managed twentieth on the grid for the start of the race in the fastest car; with both cars failing to finish. The car of Dibley and Tullius suffered a wheel bearing failure which took three hours to repair, before being disqualified 60 laps into the race by the FIA for not covering a minimum 60 laps, and a fuel-starved TX driven by Thompson and Heppenstall crashed at Indianapolis Corner; ending their effort.

After the 1968 season, the main sponsor and supplier Howmet decided to pull their support of the program as they felt it was not promoting them enough; resulting in the end of competition for the Howmet TX.

Land Speed Records

Whilst they still owned the two Howmet TX cars, Howmet decided to put them to the test in 1969 at some Land Speed records for promotional purposes; deciding it would be cheaper than a race program. Heppenstall repaired the second TX Chassis, GTP2, adapting it to open-cockpit bodywork to go for the Land Speed Record. The new MK.II Howmet TX aimed to break the Land Speed record for Turbine powered cars, attempting it in both the 500-1000kg class and the 1000kg and beyond class due to the cars ballast distribution allowing it to sit on the borderline and contest both classes.

Ray Heppenstall managed to set six records recognised by the FIA, 3 records in each weight class. This included a top speed of 104.37mph in a 1km standing start, and 93.52 miles an hour with additional ballast in the 1000kg class.

After Howmet

In 1971, Howmet ended their promotional use of the two Howmet TX Chassis that had been built, both being sold to Ray Heppenstall for a dollar. Unfortunately they were left without drive, as the Continental Turbine units were on loan from Continental, having to be returned to them after the contract was up. After this, Heppenstall sold both Chassis with #GTP1 stored in Jim Brucker’s personal collection and restored with an original Continental turbine engine.

The second chassis, GTP2, was converted back to the closed-cockpit design after its Land Speed record attempts by McKee Engineering, now owned by Chuck Haines. An Allison 250C18 Turbine was installed as opposed to twin Continental Turbines as they were not obtainable, the GTP2 now running in promotional events.

Howmet TX Turbine Engine - Allison 250C18

Whilst Haines owned the GTP2 Chassis, they created a spare frame with Bob McKee that would become GTP3. This was completed again to the original specification but featured an Allison turbine again due to the unavailability of Continental turbines. This new GTP3 has minor differences, with top exit exhausts as opposed to rear-facing exhausts and no longer has a wastegate system. It is raced in Historic events throughout the year, most recently appearing at the Monza Historic.

Want to see the Howmet TX in action? Check out this onboard from the Monza Historic from the Goodwood Road & Racing channel, and did we mention the pilot only has one hand? Check it out here!

Jared Hodges

Project Codemasters – Joining Forces with SMS

Previous article

Touge – The Japanese Mountain Back Roads

Next article


Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

You may also like

More in Endurance