The Bloodhound Will Stay On the Ground At 1,000 mph 242
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."
And for the rest of the world... (Score:5, Informative)
1000 mph=1609 km/h
Re:And for the rest of the world... (Score:2, Informative)
Re:Intel FPU? (Score:4, 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 [umn.edu]
Re:And for the rest of the world... (Score:4, 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
Re:Motor cars weren't (Score:5, Informative)
http://en.wikipedia.org/wiki/Automobile#Etymology [wikipedia.org]
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:I'm debating if this thing really counts as a c (Score:3, Informative)
Re:Intel FPU? (Score:2, Informative)
I would interpret this as:
In other words, it is a coding error.
Re:Easier solution (Score:5, 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.
The race is on (Score:3, Informative)
Re:Intel FPU? (Score:1, Informative)
It actually an unhandled ecepetion that caused it to explode, not a floating point conversion error. The programmers did not decide to catch that error when they knew it could have happened. Ada already supplies a method (I think) that handle floating point to 16 bit integers.
Re:Motor cars weren't (Score:3, Informative)
The...name car is believed to originate from the Latin word carrus or carrum ("wheeled vehicle")...
Excellent point! You've totally refuted the OP's point about this not being a real car.
Let me show you a few "cars."
Here's one! [3d-screens...nloads.com]
Here is another "car" [niu.edu]
These are all really fast cars! [shoppersdrugmart.ca]
There's no separate league for cars driven by internal combustion engine, but here [wikipedia.org] is the fastest of those.
Re:Easier solution (Score:3, Informative)
Not necessarily - only while exhaust gas speed doesn't exceed the rocket speed. A rocket engine will -still- be propelled when the exhaust gas travels in the same direction as the engine, only slower than the engine. (engine travels at 3 Mach, exhaust speed is 2 Mach, per every kg of fuel ejected the engine gets 2 Mach*kg thrust, despite the ejected gas still traveling at 1 Mach in the same direction as the engine.)
Of course the question remains whether the "break even" point (where exhaust speed equals rocket speed so exhaust gas remains static relative to surrounding air) can happen in the atmosphere, with air friction, but that's a technological barrier, not a physical one.
Imagine: a cart with two catapults on it, (total wt. 1kg). First catapult is then loaded with 2kg ball and propels its load to 4m/s. The second one is loaded with 1kg ball and can propel its load by 2m/s.
Spring the first catapult. The 2kg ball is launched at 2m/s while the cart with its 1kg ball payload starts traveling at 2m/s in the opposite direction.
Now spring the second catapult: the 1kg ball gets launched at 1m/s backwards relative to the cart speed while the cart accelerates by another 1m/s.
Now note the second ball travels at 1m/s forward in absolute terms...
Re:I'm debating if this thing really counts as a c (Score:3, Informative)
Re:I'm debating if this thing really counts as a c (Score:3, Informative)
Umm...I've been watching F1 for a lot of years, and I'm pretty sure you never got more points for a DNF than for a second place. DNF = 0 points (except in very unusual circumstances), 2nd = 8 last year or 18 this year.
As for a DNF killing your season, that's crap. Button won the championship last year and got 1 DNF, Hamilton did the same the year before. In 2007 Raikkonen won the championship despite 2 DNFs, likewise Alonso in 2006. For a driver to complete every race in the season is pretty rare, particularly if they're actually competitive (and thus driving hard).