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Friday, June 27, 2008

British Steam Car Hits the Road En Route to 170 MPH at Bonneville


British Steam Car
THORNEY ISLAND, England — “No one goes round the back, there’s 360 horsepower of colorless death ’round there.”

It was a statement that made nearby fireman at a secure military base here prick up their ears. The British Steam Car, a potential Land Speed Record breaker, wasn’t belching its intense fire when it revved up on a track for the first time today, so there was no need for the firefighters’ services. Still, loose talk about dangerous infernos from Matt Candy, the vehicle’s project manager, was bound to get their attention.

The Jules-Verne-meets-Batmobile vehicle is being loaded up for a trip across the Atlantic, bound for the Bonneville Salt Flats and a potential rendezvous with racing history in late August. Burning liquid petroleum gas at 750° F to pressurize that 360-hp Curtis turbine, the 25-ft.-long Steam Car can turn 10.5 gallons of water a minute into some boiling-hot action for the record books—and wicked fast, with velocities in excess of 150 mph. That’s not much compared to the absolute land speed record of 763 mph, but it would be enough to top the 88-year-old international steam record of 127.66 mph­. The target speed for later this summer: 170 mph.

When the attempt is made, it will be the first time the Steam Car will run as a complete unit. All the car’s systems have been exercised individually on a test bed, and it got an eye-popping early workout in motion here today. But the whole thing will run together for the first time in the third week of August, when the supersonic engineering team will test the time-bending machine prior to an all-guns-blazing attempt at the record the following week.

“When I heard it was a steam car, I certainly had some mixed feelings about coming out of record-breaking retirement,” said Don Wales, nephew of the late Donald Campbell and grandson of Malcolm Campbell, who between them set some 20 land and water records. Don himself set the electric-car Land Speed Record in Bluebird Electric in 2001, and serves as chief test driver for the Steam Car. “The driver’s cockpit is probably the safest place on the entire car—it’s the blokes working on the machine who face the most risks.”

If the speeds the team aims to break are modest by most standards, the technical challenges certainly aren’t. The biggest problem has been the 12 micro boilers that have to make super heated steam, very quickly. Getting the maximum amount of energy from the burners into the water without allowing it to escape has been a formidable challenge.

Unlike a steam locomotive, which uses a steam-powered injector system, the British Steam Car uses compressed-air-powered hydraulics to inject distilled water and pre-prime itself. The water is pumped into the start of 1.86 miles of tubing to develop three megawatts of heat to convert water into 750 F steam. This super-heated “dry” steam is then directed down the car via heavily lagged pipes and two enormous industrial steam valves, which act as throttles, and then into the two-stage turbine. “That’s where we turn pressure into velocity,” says Candy. The steam is injected into the turbine at over two times the speed of sound; under the assault, the turbine revolves at up to 13,000 rpm. The turbine drives the rear wheels via a conventional crown wheel and pinion. The vehicle turns 10.5 gallons of water a minute into super-heated steam at 40 times atmospheric pressure.

“It’s a total-loss system,” says Candy. “We’re not condensing the steam or anything, we just throw it out the back and, as a consequence, we’re only about 10 percent thermally efficient.”

It takes longer to start the machine than it can run—eight minutes to get going with enough fuel, compressed air and water to run for three minutes, although the vehicle only needs two minutes to cross the measured mile. “We’ll actually coast through the line,” says Wales. “We’ll then let it roll to a stop rather than use the brakes, and by the time the team manages to find it, things should be cool enough to turn it around and prepare for the return run. If they can’t find it, it’s got a GPS system on it.” —Andrew English
Original here

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