No car built to attack the land speed record has ever been as complex as Thrust SSC, the Castrol-sponsored jet car that will shortly begin its build-up on the Al Jafr Desert in Jordan. But then no other car has taken such close aim at breaking the Sound Barrier on land, nor has any other team taken such a scientific and painstaking approach to the task of exceeding 750mph (1207kph) without leaving the ground.
Jeremy Bliss, an irreverent 34-year-old engineer, is one of the men whose unenviable task has been to create systems that will keep the 54 foot (16.4m) long, Rolls-Royce Spey bypass turbojet-powered car glued to the ground as driver Andy Green speeds into the history books. While Chief Aerodynamicist and Research Co-ordinator Ron Ayers has been responsible for the concept and shape of Thrust SSC, and Chief Designer Glynne Bowsher has looked after the mechanical side, Bliss is in charge of the highly complex electronics.
For the first time in the near century-old history of the land speed record, a car will use the same sort of computer-controlled active suspension that Grand Prix cars used to employ, to maintain the perfect aerodynamic pitch at all times. Bliss, with a background encompassing both aerodynamics and active suspension design and development for McLaren, Lotus and Farnborough's Defence Research Agency, has been working on it for the past 18 months. "The design, by its very nature, is driven by how the project is. There are things I would have done differently if I'd had a huge budget, but the only thing I won't compromise on is safety," he stresses.
The active ride in Thrust SSC is a basically straightforward pitch control system, designed to control the attitude of the car to the ground. The system makes measurements and small compensatory changes continuously, to maintain the rear ride height that the designers initially selected. By controlling the rear ride height, it is possible to control the angle at which the nose of the car points to the ground, and hence its overall pitch stability at high speed.
The exploratory nature of Thrust SSC underlines the need for plenty of speed runs before any record attempt is made, and the need to proceed in carefully planned increments. Initially these may be up to 50mph (80kph), but once speeds reach the transonic region, the team will proceed by 0.1 of a Mach number per run (the vehicle's Mach number is defined as the expression of its current speed as a percentage of the Mach One speed - 750mph (1207kph). The Mach One speed varies slightly with temperature and attitude).
Bliss believes that Thrust SSC's ground-breaking nature extends far beyond active ride, however. "I would say that the biggest departure with this car is the amount of research, and the complexity of the data systems. I think it is a quantum leap. It was two years in the planning, it uses finite element analysis, computational fluid dynamics (cfd) to determine the shape, the data system is pretty comprehensive, and all the sensors give information on how it is behaving. The data system allows you to develop the car far more quickly because you have the information straight away.
"I think that is the big advance, the use of computer technology. Not only the onboard technology, but computer technology as a tool. It has been used very effectively, and as far as I know that is the first time it has really been done in a land speed record car. I don't think any of our rivals have done anywhere near our level of research. Maybe this will become the benchmark for future world land speed record cars, or maybe we have it wrong and it will have to be done a completely different way. But I am very confident in what we have done."
Bowsher agrees. "I think the principal difference is that we are sensing as many things as possible, whereas on Thrust 2 as few things as possible were sensed. And where that makes the huge difference is in the time it takes to turn the car around, as I well remember because with Thrust 2 I was on Start Team 2. It took 45 minutes then, of the magic hour you are allowed between runs. The one thing I had to do was remove the front panels and check all the suspension, the bearings and the brakes, the steering. And that took time. We can't afford that on this car because it's much more difficult."
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