October 26, 2008

The 1,000mph jet car

A British team aims to smash the land-speed record with weird science

 

Did your car feel a little underpowered this morning? What you need perhaps is a Eurofighter Typhoon jet engine under the bonnet. Plus, for good measure, a Falcon solid-fuel rocket engine, and for an extra kick, a V12 racing engine. That would give you a top speed of, let’s see, roughly 1,050mph, and allow you to travel 10 miles – a typical journey to the newsagent’s and back – in 34 seconds.

Say hello to the Bloodhound SSC, a 42ft-long vehicle (you can hardly call it a car) in which Wing Commander Andy Green, a former RAF pilot, will attempt to break his own land-speed record. It is 11 years since Green became the first driver to travel faster than the speed of sound, hitting 763mph in the Thrust SSC (supersonic car). The Bloodhound is set to beat that by more than 200mph, reaching 1.4 times the speed of sound. Blink and you’ll miss it. Really. In the sixth of a second it takes you to blink, it will travel nearly the length of a football pitch. This monstrous contraption is blessed with the power of 1,200 family cars. The fuel pump alone has 800 horsepower.

First, though, Green and Richard Noble, the team leader, need £10m in sponsorship to develop and build the car. Noble, who also headed up the Thrust SSC team in 1997, has already got endorsement from Lord Drayson, the science minister, and the gift of the Typhoon engine from the Ministry of Defence, for whom Green works.

If all goes according to plan (and that’s a big if), construction will be completed by the end of next year, leading to the 1,000mph record attempt in 2011. It will put the land-speed record firmly – possibly for the foreseeable future – in the hands of the British, with a supersonic speed that’s actually faster than the 994mph low-altitude speed record for an aircraft.

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That kind of velocity has to be built up in stages. First the Typhoon engine launches the car. At 300mph, the Falcon solid-fuel rocket engine (designed and built in Britain) will kick in, with its peroxide fuel being slammed into it at a pressure of 1,200psi by the V12 racing engine. With nine tonnes of thrust coming from the jet engine and another 12 tonnes from the rocket, the car will accelerate within seconds beyond the muzzle velocity of a .357 Magnum. Enormous forces will build up on the bodywork, which will have to withstand greater pressure than a military submarine – more than 12 tonnes per square metre.

Aerodynamic forces will alternately make it want to fly and dive into the ground. Computer-controlled “winglets” (see graphic), on either side of the nose, will hopefully prevent this. The wheels turn at 10,500rpm, their rims subjected to g-forces equal to 50,000 times the force of gravity.

Each component of the car will have to be precision-made. The wheels will be machined from titanium, but who can machine a block of titanium that big? It’s never been done. Within five miles, the Bloodhound SSC will smash through 1,000mph before beginning a savage deceleration that will subject the driver to a sustained pressure of minus 3g. The mathematicians and aerodynamicists – including the fabled (in engineering circles) Ron Ayers, who developed the Bloodhound missile in the 1950s, after which the project is named – believe it is possible.

But at such superhuman speeds, if something goes horribly wrong, the only difference between 700mph and 1,000mph is how thinly you’re spread across the ground. Fortunately, having already set one land-speed record, Green, 46, has proved he can drive at insane speeds, making counterintuitive steering corrections, reading all the dials while checking instruments and talking on the radio at the same time.

He remains sanguine about the dangers: “It’s all about risk minimisation and risk management,” he says, demonstrating the sort of calm logic that earned him a first-class degree in mathematics from Oxford. “It would be wrong to say I’m not nervous about it, but I’m sure there is a very high probability that the goal can be achieved.”

The speed of sound varies according to altitude, but at sea level it is about 761mph. As the car approaches that speed, shockwaves will build up in front of the nose cone and as it goes past the sound barrier it will burst through a wall of air pressure, creating an eardrum-shattering sonic boom.

“The critical thing is to keep the car on the ground and going in the right direction,” says Green. “It’s not a case of saying ‘blimey, this is fast’. If anything, it’s another sensation. It’s like the slow-speed feeling you get just before a car crash – only it lasts for about two minutes.”