When Andy Green, already the world's fastest man, begins his 2012 mission to push the World Land Speed record to 1000mph by driving his Bloodhound SSC car through a measured mile 240mph faster than he's ever gone before, he won't have long to savor the occasion.
At that speed, the mile will occupy just 3.6sec, maybe seven or eight heartbeats' worth. If he blinks, Bloodhound will cover 500ft by the time his eyes open. It will be going faster than a bullet fired from the world's most powerful rifle and its one-piece aluminum wheels, each weighing 209lbs, will be turning nearly 2000 times every second. His rocket motor, working in tandem with a gas turbine from a Eurofighter jet also along for the ride, will be consuming hydrogen peroxide at a rate of one ton every 20 seconds.
There will be no room for a sense of relief when Green flashes past the second marker, either. If he's a second late hitting the airbrakes (then chutes, then discs) he'll overshoot the carefully positioned refueling trucks by such a distance – Bloodhound covers the length of four and a half football fields in one second – that they simply won't be able to recover the car in time to run again within an hour, as the rules require. It is an enormous challenge.
The Bloodhound program is already two years old, beginning in earnest in 2008 when British industry minister Lord Drayson agreed funding of £600,000 ($940,000), provided the team did its utmost to attract a new generation of school children to flagging STEM subjects: science, technology, engineering and math. They did, and can point to considerable success that continues to increase.
However, the bid has lately gained new impetus with the unveiling of a full-sized mock-up, 42ft long, 9ft high, and with a shape and layout decided by research through 10 iterations and involving the know-how of experts from the successful Thrust SSC land speed record project of 1997: leader Richard Noble, aero expert Ron Ayers and Andy Green himself.
Why so many versions? Because everyone agrees that a 1000mph car needs to be as benign and vice free as possible. Chassis designer Brian Coombs cites the suspension as an example. “Our setup – double wishbones front and rear – is designed to have no camber change, because if there were any, the gyroscopic forces generated would be too great for Andy to control. The same goes for the steering, which is extremely low geared by road car standards and has zero offset.”
Bloodhound's detail design phase is under way now at the team's impressive headquarters provided by the city government of Bristol, right next to Brunel's famous SS Great Britain near the heart of the city. This is where the full-sized car will be built. The team, which runs to around 20 people, has already issued a detailed specification for the car and will follow that with plans.
“We don't need F1-style secrecy,” says Mark Chapman, jet fighter designer and chief engineer. “We'd rather interest people in what we're doing. In theory, anyone with spare jet and rocket motors on hand will be able to build a Bloodhound of his own.”
The car will weigh 7.3 tons, and even at that vast size the designers say “it's full.” Green's tightly packaged cockpit sits immediately behind the needle nose, his feet just behind the narrow-tracked front wheels, which have no tires because rubber hoops simply wouldn't stay in place above about 400mph. The front section of the car, including cockpit, is a race-style carbon fiber survival cell.
Behind that is a massive aluminum spaceframe carrying first the 264-gallon hydrogen peroxide tank (which promotes burning of the solid fuel pre-loaded into the 5m rocket motor). Behind the peroxide tank is an 800hp F1 engine (maker still to be decided), chosen for its size-to-power ratio, to pump fuels, peroxide to the rocket and jet fuel to the gas turbine. Sandwiched between that pump engine and the rocket motor is the jet fuel tank. The two propulsion engines – rocket and jet – are sited so that their combined thrust acts through Bloodhound's center of gravity.
When driven in anger, Bloodhound will start rolling on its jet engine alone, taking a tortoise-like 15 seconds to reach 100mph – slower than many road cars. Thereafter, everything changes. Team calculations say Bloodhound will accelerate from 100mph to 1000mph in just 25 seconds. The jet engine will do all the work to 350mph, when Green will press a button on his U-shaped steering wheel to fire the rocket and acceleration will increase to around 2g. Seven or eight seconds later, at about 650mph, parts of the airflow over the car start to go “transonic” – a phase that can alter their aerodynamics in ways that aren't entirely predictable.
That's where a car's fundamentally benign aerodynamic design becomes invaluable. Team calculations show the car reaching 1000mph under 2g acceleration about half a mile before the measured mile begins, then braking at 3g immediately afterward. The team's turnaround expert, engineer Annie Berrisford (who had the same job in the JCB Dieselmax LSR team), says there's a good 45-50 minutes of work needed to ready Bloodhound for its return run. It's tight, she says, but doable.
Construction of the car is beginning now. The plan is to build through next year and have a car ready to roll by the end of it. UK runway shakedown work up to 200mph should begin in the early months of 2012, after which the car should make its first trip to Hakskeen Pan, the fast and smooth South African mudflat course that has been chosen for record runs after a worldwide search. Green, now a world authority on tracks for supersonic speed runs, recently gave it his seal of approval while traveling in South Africa on his honeymoon.
If all goes well, Bloodhound could just crack 1000mph in the late summer of 2012, but everyone acknowledges there are large hurdles to overcome. One of the biggest is money. “We've got just over two years to raise $5.5 million,” says team principal Richard Noble, still the world's second-fastest man. “In times like these, that's tough.” It is, but Noble and his Bloodhound team have the consolation of knowing they've done it all before.
Steve Cropley/Autocar