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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."

24 of 242 comments (clear)

  1. But what happens when... by Fluffeh · · Score: 3, Funny

    Righto, time to ask the serious questions! But what happens when they hit 88 miles per hour?

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    1. Re:But what happens when... by drb_chimaera · · Score: 4, Funny

      Dude, in factors of 88mph this thing goes to 11 ;)

  2. Easier solution by Jeoh · · Score: 4, Funny

    Why don't they make it drive on a treadmill?

    1. Re:Easier solution by PhongUK · · Score: 4, Insightful

      They would have to then engineer a treadmill that can move the belt at 1000MPH, a wind machine that can blow wind at 1000MPH so that the Bloodhounds engines get the intake that it needs. They would then likely have to take care of all the exhaust gasses... ... AND IT WOULDN'T BE AS COOL!

    2. Re:Easier solution by SharpFang · · Score: 4, Insightful

      Since it's a jet engine (pushing against the air), it would be the old "Plane on a treadmill" problem. Meaning it would drive off the treadmill.

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    3. Re:Easier solution by somersault · · Score: 4, Funny

      There is a high tech solution for that, it's called a "strap".

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    4. Re:Easier solution by stiggle · · Score: 3, Interesting

      Its a jet engine pushing it up towards 1000mph, but its a solid fuelled rocket (liquid oxidiser) that pushes it over.
      A lot of their design towards the end of last year was deciding whether to put the Jet over Rocket (JoR) or Rocket over Jet (RoJ) in the tail of the vehicle.

      They decided on the JoR configuration as it provided better stability & airflow through the jet.

      This project is also about getting kids interested in engineering again, and they're making their data publicly available.

      They've been touring with the full size model of the car visiting towns doing workshops with the school kids about the stuff they're doing and experiments & tests the kids can do themselves. They were kind enough to park the car outside my office when they were in my home town.

    5. Re:Easier solution by SharpFang · · Score: 4, Informative

      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.

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  3. I'm debating if this thing really counts as a car. by pecosdave · · Score: 5, Insightful

    Seriously, you rip the wings off of a fighter jet and make it stay on the ground does it become a car? To really be a "car" I would almost argue it needs to be propelled by the wheels.

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  4. And for the rest of the world... by iJusten · · Score: 5, Informative

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

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    1. Re:And for the rest of the world... by hcpxvi · · Score: 4, Funny

      Those are both wuss units. Real physicists measure speed in metres per second.

    2. Re:And for the rest of the world... by beelsebob · · Score: 3, Informative

      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

    3. Re:And for the rest of the world... by Philip_the_physicist · · Score: 4, Funny

      I;m sure there is an equivalent of Godwin's Law for stories related to science or technology, regarding the correct size of the kilobyte.
      Until someone names it though, remember that Hitler would have supported decimal kilobytes :)

  5. Don't they realise what they've done?! by krou · · Score: 5, Funny

    "that amount of lift is enough to make the car fly"

    At last!

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    1. Re:Don't they realise what they've done?! by bkr1_2k · · Score: 4, Funny

      That's not flying. It's falling, with style.

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  6. Re:Intel FPU? by alanw · · Score: 3, Informative

    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

  7. I don't think it does by Viol8 · · Score: 3, Insightful

    The only thing it has in common with a car is that it has wheels and runs on the ground. Given its size and weight it would be more accurate to call it a jet powered truck.

    IMO the real land speed record is the wheel driven ones , not the one where you just strap a huge rocket on the back and try and stay on the ground.

    1. Re:I don't think it does by hanabal · · Score: 3, Interesting

      If this works it will be travelling across the land with a higher speed than anything that has ever travelled across the land, hence the title "land speed record". I agree with you that the wheel powered one is in some ways more important, but something has to be declared fastest land vehicle and it seems fitting for it to be the fastest vehicle on the land. If Fred Flinstone could run fast enough to make his car faster than any other car in history, would you deny him the land speed record?

    2. Re:I don't think it does by JustOK · · Score: 5, Funny

      his record would be in doubt. look at the video of his record. Notice how the background seems to keep repeating over and over again.

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  8. Re:I'm debating if this thing really counts as a c by Hadlock · · Score: 4, Interesting

    Depends on if it's a fixed aero-surface vehicle or not. F1 cars had variable surface aero-parts for one or two years before they were outright banned. The idea was that you could increase the angle of attack to increase downpressure in the corners, but make the car aerodynamically neutral in the straightaways so you're spending more power on thrust rather than dividing it between thrust and downforce. Depending on how the rules for "world's fastest car" are written, how the aero is done determines how impressive this really is. If John Carmack can write a javascript to control thrust for a vertical takeoff rocket (Armadillo Aerospace), you can design a fast car with dynamic aerosurfaces. Building a fixed aero car that's neutral at 1000mph but won't fly into the air and flip when you hit a rock is a lot harder to do. Check out this hella sweet video of a Le Mans car doing exactly that at 220mph: http://www.youtube.com/watch?v=wM4guvo6Ifo
     
    I'll admit this post was an excuse to post that video, but damn if it isn't cool. And that's at a quarter of the speed at which they'll be attempting this. It's not as easy as it looks.

    Here's another cool video of the same thing happening. It's relatively common, even though they design against this exact sort of thing from happening. http://www.youtube.com/watch?v=y65oUlBMSUs

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  9. British space program failure by Kupfernigk · · Score: 4, Funny

    Once again it fails to get off the ground.

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  10. Re:Motor cars weren't by LordLucless · · Score: 4, Informative

    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).

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  11. Re:I'm debating if this thing really counts as a c by bkr1_2k · · Score: 3, Insightful

    That has nothing to do with the fact that this simply isn't a car. It's a rocket/jet with wheels attached. Just because a plane has wheels doesn't make it a car either. Yes, it's very difficult (to understate the issue) to keep any object traveling 1000 mph on the ground, but that doesn't negate the GP's point. It's not a car. It's not designed like a car would be, it's not propelled like a car would be, and it's not driven like a car would be.

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  12. Re:I'm debating if this thing really counts as a c by Vectormatic · · Score: 3, Insightful

    i would argue that not the design method, but rather the designed purpose would determine what an object is.

    This thing is designed to move accross a hard surface supported by wheels, pretty much making it a car (notice i explicitely said wheels to rule out any funnymen with the 'but but hovercraft is a car' argument).

    It might not be a car in the traditional ford sense of the word, you wont drive your kids to school in it, and it isnt practical for everyday use, but its purpose is still driving accross terain.

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