The Britons who built the first car to break the sound barrier are back with plans to shatter their own record in a jet-powered land-rocket they’re betting will be the first car to top 1,000 mph.Royal Air Force pilot Andy Green will make his run for the record strapped into the Bloodhound SSC, a 42-foot-long missile powered by a rocket bolted to a jet engine. With 45,000 pounds of thrust available at full throttle, Bloodhound will hit 1,050 mph in just 41 seconds and cross the salt faster than a speeding bullet.
"There has never been anything like Bloodhound SSC before," says team leader Richard Noble, who set a land speed record of his own in 1983. "It is undoubtedly the most stimulating and challenging program I’ve ever been involved with. The next three years are going to be tough, testing and damned exciting."
The announcement comes 11 years after Noble and Green set the current land speed record of 763.035 mph in the Nevada Desert and continues a British tradition for speed that dates to the 1920s and ’30s, when Sir Malcolm Campbell set several records on land and sea. Britain has held the land speed record for 58 of the 109 years since Count Gaston de Chasseloup-Laubat of France reached a blistering 39 mph in a suburb of Paris.
More than bragging rights are at stake in the ambitious project announced today. Noble and Lord Drayson, Britain’s minister of state for science and innovation, hope the three-year project will inspire children to pursue careers in engineering, mathematics and science, so they might solve the world’s most pressing problems.
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The project will use YouTube videos, Twitter feeds and other social networking tools to keep kids — and others — around the world up-to-date on Bloodhound’s progress and encourage them to engage with the team. "Ultimately, I hope that this iconic British project will encourage the next generation of scientists and engineers, as we will depend on them to find the solutions to everything from climate change to growing population pressures," Drayson says.
Drayson, himself a race-car driver, was Britain’s defense minister when he approached Noble and asked if he had any ideas that would capture the imaginations of the nation’s children. Drayson fears kids are losing interest in science and engineering, and he’s worried about the impact it will have on the United Kingdom. "The consequences if we don’t inspire the next generation are that we will wither as a country," he told BBC News.
Noble quickly signed on and set his sights on surpassing 1,000 mph on four wheels. He knows a thing or two about land speed records, having designed the ThrustSSC. That vehicle set the current land speed record in 1997 when Green crossed Nevada’s Black Rock desert at 763.035, becoming the first driver to break the sound barrier. Noble has spent 18 months developing the Bloodhound concept — the car hasn’t been built yet, and won’t make its run for the record until 2011 — from a clean sheet of paper. "The target is 1,000 mph," he says. "That’s a 31 percent jump (over ThrustSSC), and there is no way Bloodhound SSC is going to look like anything we have seen before."
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Noble calls Bloodhound "a jet and hybrid rocket." A Falcon rocket generating some 25,000 pounds of thrust will get the car up to the speed of sound (340.29 meters per second, or 761.2 mph). At that point Green will use a Eurojet EJ200 jet engine producing 20,000 pounds of thrust to take Bloodhound the rest of the way to 1,000 mph. A V12 engine will drive Bloodhound’s hydraulic system, serve as a starter motor for the EJ200 and pump high test peroxide fuel through the rocket at the rate of one ton every 22 seconds.
All that power is useless without aerodynamics, and Noble says "the Bloodhound SSC shape is completely different to anything seen before. We need to minimize the cross-sectional area to minimize drag, but we also need a supersonic intake and a smart suspension system, which will enable the car to run smoothly over the rough salt surfaces."
Bloodhound is 42 feet long, 9 feet tall and will weigh 6.4 tons. With the rocket mounted above the jet engine, the center of gravity is so high, the rear wheels must be suspended on outriggers. In the past, that would have created excessive drag, but Noble says computational fluid dynamics allowed him to find the optimal shape for aerodynamic efficiency. Bloodhound also uses an unusually small rear fin, but Noble is confident he’s achieved the best compromise between the stability of a large fin and the aero efficiency of a small one. Small winglets above the front wheels can be adjusted on the fly to maintain a constant level of downforce as the vehicle approaches Mach 1.4.
Downforce takes on a new meaning when you’re shooting for 1,000 mph — a speed Noble estimates Green will need 4.5 miles to achieve (it’ll take about that far to bring it to a stop afterward). The air pressure bearing down on Bloodhound’s carbon fiber and titanium body at Mach 1.4 will exceed 12 tons per square meter and its 35.8-inch rear wheels will be spinning at more than 10,000 RPM. They’ll be made of titanium to keep them from flying apart.
At that speed, Green will be covering about 400 yards a second, or about 50 meters in the blink of an eye. He admits it’ll be risky, but says Bloodhound will be designed to maximize safety. "Does that make it zero risk?" he told BBC News. "No. Is life with zero-risk interesting? No."
Source: http://www.wired.com/autopia/2008/10/supersonic-jet/
