The Bloodhound Will Stay On the Ground At 1,000 mph

Hugh Pickens writes "BBC reports that engineers designing the world's fastest car, the Bloodhound SSC, built to smash the world land speed record of 763 mph set by the Thrust SuperSonic Car in 1997, believe they have a solution to keep the vehicle flat on the ground at 1,000 mph after initial iterations of the car's aerodynamic shape produced dangerous amounts of lift at the vehicle's rear. John Piper, Bloodhound's technical director, said: 'We've had lift as high as 12 tonnes, and when you consider the car is six-and-a-half tonnes at its heaviest — that amount of lift is enough to make the car fly.' The design effort has been aided by project sponsor Intel, who brought immense computing power to bear on the lift problem. Before Intel's intervention, the design team had worked through 11 different 'architectures' in 18 months. The latest modelling work run on Intel's network investigated 55 configurations in eight weeks. By playing with the position and shape of key elements of the car's rear end, the design team found the best way to manage the shockwave passing around and under the vehicle as it goes supersonic. 'At Mach 1.3, we've close to zero lift, which is where we wanted to be,' says Piper. In late 2011, the Bloodhound, powered by a rocket bolted to a Eurofighter-Typhoon jet engine, will mount an assault on the land speed record, driving across a dried up lakebed known as Hakskeen Pan, in the Northern Cape of South Africa."

Comments

And for the rest of the world...

[iJusten]

763 mph=1 228 km/h
1000 mph=1609 km/h

Re:And for the rest of the world...

[beelsebob]

That's the same unit. kilometers per second is kilo (1000s of) meters per second. The kilo part is an SI prefix, not part of the unit. Just like kilobytes means 1000s of bytes and kilograms means 1000s of grammes.

Bob

Re:Intel FPU?

[alanw]

If there was a bug, it's unlikely the final result would make sense. "It would go fastest with the engine in the ground!", or "it would go fastest with the engine backwards!". With that many calculations, one error would be magnified.

A floating point conversion error caused an Ariane 5 rocket to explode back in 1996

http://www.ima.umn.edu/~arnold/disasters/ariane.html

Re:Motor cars weren't

[LordLucless]

http://en.wikipedia.org/wiki/Automobile#Etymology

The...name car is believed to originate from the Latin word carrus or carrum ("wheeled vehicle"), or the Middle English word carre ("cart") (from Old North French), or karros (a Gallic wagon).

Re:Easier solution

[SharpFang]

The air it ejects backwards moves way faster than Mach 1 relatively to the engine. The momentum of ejected material must be higher than momentum of intake material. With rockets, there's no intake material, and it depends strictly on ejecting most of its mass backwards. Speed is a boon but even ejecting the mass slower than the speed of surrounding air (or near-void) gives it thrust.

With jet, the momentum of air at the intake (which is zero, immobile air) must be lower than exhaust mix ejected backwards, and considering the mass of the jet fuel used is quite low comparing to mass of air used, the mass of the exhaust gas is not significantly higher than mass of intake air, so it must use higher speed to achieve higher momentum and thus thrust - so no matter how fast the plane moves, exhaust gas always moves backwards relative to static air - thus pushes against static air and as result creates a pressure pillow.