Bloodhound gang: the team behind the supersonic car

Back in the 1970s, I had an obsession with Top Trumps. There were different sets of these cards - footballers, racing drivers, aircraft - but the game was simple. Each card carried a series of statistics - for a footballer, it might be number of appearances or goals scored. To play, you’d pull cards off the top of the pack and call out one stat. Other players would compare that figure with their card. The highest would win.

Everyone had a favourite Top Trumps pack. Mine was the World Land Speed Record. The cars, with their amazing names and outlandish shapes. The drivers - the Brylcreemed Brits of the inter-war years; the razzle-dazzle drag-racer Americans.

At a press event for the latest land speed record attempt, it appears that these cars have lost none of their power to enrapture children. A 10-year-old boy and his little sister run up to the full-size mock-up of Bloodhound SSC, the jet and rocket-powered vehicle that is aiming for a record speed of 1,000mph in 2013, and stop in their tracks two metres from the car’s low, pointed nose, their mouths and eyes wide. Looking around, many of the assembled journalists are clearly trying to suppress the same reaction.

After three years of development, Bloodhound is finally becoming a reality. Construction work began on the rear of the car earlier this year at Hampson Industries in the West Midlands. The Bloodhound team, under project leader Richard Noble and chief engineer Mark Chapman, expects the car to be complete next year, with shakedown tests in the UK, before starting its attempt at the record in South Africa, at a site on the edge of the Kalahari Desert called Hakskeen Pan, in 2013.

But while the components are beginning to come together, this represents the culmination rather than the start of the engineering story of Bloodhound. Named after a 1950s British surface-to-air missile, the car represents a blend of 21st century engineering analysis with updated Cold War technology and a mixture of personalities and talents you’d be unlikely to see in any other type of project.

Noble has a record in this field. Himself the holder of the record from 1983 to 1997 in Thrust 2 and director of the project that took the mark to 763mph (1,228km/h) with Thrust SSC, his blend of patrician drawl and bluster, combined with the cool demeanour of the project’s driver, Wing Commander Andy Green, has been instrumental in attracting the support that the project has needed to get to this point.

Chapman is an aerospace engineer who joined the Bloodhound SSC project after working with Green on the diesel-powered land speed record breaker JCB Dieselmax, and is a typical results-focused realist. The designer of the rocket component of Bloodhound’s power plant, Daniel Jubb, is a more flamboyant figure, with a handlebar moustache that would be the pride of any Battle of Britain pilot.

These people are tackling a target that involves accelerating a 6.5-tonne car up to a peak speed of 1,050mph (1,690km/hr) - the record is an average over a measured mile, so the peak speed will be higher than the record speed - over an 8km distance, from a standing start, back to a stop in the same distance. It, and its driver, have to withstand acceleration and deceleration of 3g. ’It has 133,000hp and it all happens in 100 seconds,’ Noble said. ’The measured mile happens in 3.6 seconds.’

Noble described the challenge as a trek into unknown territory. ’Of course, no one’s done this before, so we have no precedent to help us. The aerospace industry doesn’t do these sorts of speeds along the ground, and motorsport only goes up to about 200mph. It was apparent that it was going to be very hard to get the aerodynamics right, and we also realised we had to tackle every aspect of the project - the aerodynamics, the engineering design and the rocket programme - in parallel, otherwise it would have taken us 25 years.’

The twin power plant of the vehicle is a particular source of engineering trouble. The jet engine, which provides half of the thrust and all of the output control, is a Eurojet EJ200, the unit that powers the Eurofighter Typhoon and, at the outset of the project, the most advanced military jet engine available. Noble persuaded Rolls-Royce and the Ministry of Defence to lend the engine to the project by committing Bloodhound to a link-up with education, to promote engineering to schoolchildren, but the engine is fulfilling a role it was not designed for. ’Rolls-Royce did a one-month scope to see what was involved in installing an engine in our car,’ Noble said. ’That has problems, because the car goes faster than a Eurofighter, so we need to restress parts of the engine.’

“We have no precedent to help us. The aerospace industry doesn’t go along the ground, and motorsport only goes up to about 200mph”

Richard Noble, Bloodhound SSC project leader

The rocket component, providing the thrust to take the car through the record mark, had to be developed from scratch. ’There are three types of rocket,’ Noble said. ’Solid fuel is like a firework: lightweight and cheap, but once it’s been lit, you can’t stop it. Liquid fuel rockets require a government-scale budget to develop to a high enough standard, and if you get it wrong, you blow up the car. We went for the hybrid option, with a liquid oxidiser and solid fuel, which works as long as you’re pumping in the oxidiser. But there’s nothing available off the shelf.’

This brought in Jubb, a rocketry prodigy who started his company, the Falcon Project, aged 11, and who now designs and builds rockets for commercial and defence applications. ’The rocket uses high-test hydrogen peroxide as an oxidiser, and a synthetic rubber, hydroxyl-terminated polybutadiene (HTPB) with some additives to help it burn as the solid fuel,’ he said. ’The oxidiser is pumped in through a catalyst pack, which decomposes it at 600°C into gaseous oxygen and steam, and this passes into the hollow cylinder of the fuel. The fuel grain itself is cast into the rocket in such a way that the recession - the speed the fuel decomposes - matches with the speed that the decomposed oxidiser enters from the catalyst pack.’

“We can’t simulate the way the rocket will work in a moving car.”

Daniel Jubb, rocket designer

Development started with a 6in version of the rocket, of which 10 have now been test-fired. The first test-firing of a full-scale, 18in-diameter, 3.6m-long rocket took place last year. However, this test did not use the full system that will power the Bloodhound; peroxide was fed in under pressure from a tank. In Bloodhound, the peroxide will be blasted in by a high-pressure centrifugal pump, powered by a V8 Formula One engine, the Cosworth CA8010. ’We need to test the full system, because we have to get as close as possible to the conditions that Bloodhound itself will be seeing,’ Jubb said. ’But we can only ever approximate that. What we can’t simulate is the way the rocket will work in a moving car, with the interaction with the surface and the vibration. But we’ll run as many tests as we have to, to be as sure as we can.’

The rocket pump must pump nearly 1,000 litres of an 86 per cent concentrated peroxide - 35 per cent more dense than water - in 20 seconds.

Designing one from scratch would have been impossible in the time required, so Jubb looked for pumps that had performed similar tasks. He found one dating back to the Cold War. It had pumped peroxide into the engine of Blue Steel, Britain’s nuclear stand-off missile. Blue Steel was scrapped in 1970 and all the components and drawings supposedly destroyed, but one fuel pump was saved - legendarily, from a skip - by one of its designers, John Scott-Scott. Scott-Scott and Jubb embarked on a paper chase to track down as many of the surviving engineering specifications of the fuel pump as they could, then reverse-engineered and redesigned the pump to make it suitable for Bloodhound.

The Cosworth engine, allied with control systems from the company’s electronics arm, will drive the pump at 11,000rev/min to force peroxide into the catalyst pack. ’There are important differences between how the engine operates in an F1 car and in the Bloodhound,’ said Cosworth chief executive, Tim Routsis. ’An F1 car has a lot of lateral g, and we’ve learned a lot about keeping the oil in the right place. But the forces on this engine will be very different, with a much higher sustained g in one direction. The oil will end up in the wrong end of the engine, so we’ve designed a system to scavenge it from where we know it’ll end up, and route it back to where we want it to be.’ Moreover, the engine will be in a unique situation for a piston engine. ’There aren’t any piston engines that run in a supersonic airstream,’ Routsis said.

“There aren’t any piston engines in the world that run in a supersonic airstream”

Tim Routsis, Cosworth chief executive

Cosworth’s is the second engine that has been earmarked for this duty. Originally, Bloodhound was using a 12-cylinder unit designed by MCT, but this relationship has now lapsed. ’MCT still wants to be involved, but there were issues with the space we had available and the packaging of the engine, and Cosworth’s is a more compact unit,’ said Chapman. ’The fact that the rocket-control system and the oxidiser pump power unit come from the same firm is an advantage for us.’

Bloodhound’s wheels are also in development. Each weighing around 100kg and spinning at 10,000rev/min, they will be made from aluminium, although the precise alloy has yet to be chosen. Lockheed Martin is helping the project with this, firing samples of Hakskeen Pan rocks at alloy samples, said senior design engineer Brian Coombes. ’Both of the Thrust cars ran on aluminium wheels so we have a lot of data on how the material interacts with stones, and the stresses at 10,000rev/min are high, but within the capabilities of aluminium.’

The wheels are, in fact, designed to interact as little as possible with the surface. Three years of development on the Bloodhound body has refined a shape that generates no lift, and the shape of the wheel, designed by Thrust veteran aerodynamicist Ron Ayers, is a ’single keel’ with a ridge pushing into the ground, which acts somewhat like an aerofoil. ’The wheel lifts out of the surface slightly at speed, so only the bottom few millimetres penetrate the desert surface,’ Chapman said. ’It isn’t like flying at ground level - even with just that small amount, we have several tonnes of pressure from the surface into the car - but it reduces rolling resistance and helps us achieve the speed we need.’

The car’s shape is now locked, with only a small amount of finessing of the rear wheel fairings still in question.

The Bloodhound team is travelling the country with the mock-up of the car. It can only give a sense of what the vehicle will be like. But it already has something in common with the record-breakers of the past. It looks like it’s going fast, even when it’s standing still.