One of the most impressive prototype sports cars ever created: the Howmet Turbine eXperimental. It was the brainchild of American racing driver and engineer Ray Heppenstall and financed by the Howmet Corporation, a supplier to the aerospace industry. This car didn't have a traditional combustion engine but was powered by a compact Continental gas turbine engine originally designed for a military helicopter. It produced 350 hp and a more impressive 880 Nm of torque at a maximum of 57,000 rpm!
The idea itself was not original, it followed similar concepts as the Rover BRM turbine sports car and Andy Granatelli's STP-Paxton Turbocar. But due to some clever improvements, like an extra waste gate pipe to reduce engine lag, the Howmet TX was the most successful turbine powered racer.
Construction of the car itself was in the hands of McKee Engineering and based on the tubular chassis of a McKee Can-Am car. Internally the car was referred to as the McKee Mk 9. Two cars were completed for the 1968 season and they were extensively raced in endurance events both in Europe and the US and they even won some races. Most notable however was the participation in the 1968 Le Mans 24 Hours where the chilling whine of the turbines at full rpm on the long straight impressed a whole generation of racing enthusiasts. Unfortunately both cars failed early in that race due to technical problems.
Even though the car showed promise and was competitive, 1968 proved to be its only year in competition as Howmet decided not to fund the project any longer. Instead, the cars were used for setting some land speed records.
Originally only the two chassis were made (known as GTP1 and GTP2). In later years McKee Engineering converted a spare chassis to a complete car (GTP3) and constructor Bob McKee built a new one for himself, known as the GTP4. It's that car you see here. Because the original Continental turbine was an experimental engine which wasn't available anymore this car is powered by an Allison C250 turbine engine, modified with a waste gate like the original Howmet racers.