Meet the wild helicopter-powered Howmet TX

It was the brainchild of racing driver Ray Heppenstal. He secured funding from Howmet Aerospace, which made parts of gas turbine engines, and recruited renowned engineer Bob McKee to develop the car. Starting with a Porsche 904 windscreen – the smallest glass permitted by class regulations, he built the car around its unusual powerplant. Initial plans to base the TX – or Turbine eXperiment – on an existing Can-Am platform from 1966 were shelved. It quickly became clear that this needed to be a clean-sheet design.

Powering the TX was a gas turbine engine initially developed for a military helicopter, but the contract was cancelled. Weighting just 77kg, the engines are capable of 57,000rpm which is astonishing when compared to a piston engine. One downside of  turbine engines is the lack of compression – when the driver lifts off the throttle it takes a while for the high-revving turbine to return to tickover. The Howmet mitigates this with a wastegate that allows the gas to escape. There’s still no engine braking effect, however, which imposes a specific driving style.

The team aimed high for the Howmet’s first outing, which was the 1968 Daytona 24-hour, but the car crashed out when the wastegate failed to open, over-powering the car and sending it into the barrier. Thereafter, reliability issues plagued the car until a local race in the States where it finished in second place. The TX claimed its first victory at the Heart of Dixie Celebration in Huntsville, Alabama. It won the sprint race that determined the grid for the main fixture, and converted that pole position to win the main race itself. In the Marlboro 3000, the TX led every lap and built an impressive 11-lap lead by the time the chequered flag dropped.

Now deemed ready to compete on the world stage, Howmet entered the Watkins Glen 6 Hour. One car suffered a transmission failure, but the other achieved a podium finish overall and a class victory. That year’s Le Mans 24-hour, postponed to September, also raised reliability – and so the 1968 season was concluded.

While it hadn’t been filled with success, the experimental car showed a great deal of promise and secured its place as the first gas turbine car to win a race. It remains the only one to do so. Heppenstall had plans for the 1969 season that included a multi-speed transmission, but Howmet decided to pull the plug on the project.

Xavier Micheron has had this Howmet for 20 years, the first two years of his ownership spent bringing it back to life. At the 2024 Festival of Speed, Micheron's main objective is to put on a show rather than set a time. “When you start the engine it’s very noisy, but when you go fast it’s not very noisy,” said Micheron. 

“If you accelerate and brake, it makes more noise. That's why I try to play on the throttle, because for the public I think it’s more attractive. It makes a very special song.”

He describes it as a very simple car to drive as there’s no clutch pedal or gearlever to contend with. The real challenge it presents is on slower parts of the track, where the single-speed transmission is compromised in favour of higher-speed performance. In those environments, it’s playing to its strengths. “At Le Mans Classic, Micheron explained, "the top speed was [191mph], which is very fast, and we were lapping very well and competing against Lola T70s and beating GT40s." Given the Howmet’s short career in period, it’s now the case that Micheron has had more seat time than any other driver, so he knows the car intimately.

While he may be more than familiar with the Howmet, most on-lookers are not. He has seen spectators look to the skies when he fires it up expecting to see a nearby helicopter, while other racers comment on the smell of kerosene when they’re racing in close quarters. One thing’s for sure, it’s always capable of creating a crowd on its visits to Goodwood.

Photography courtesy of Nick Wilkinson and Fin Williams.