"The speed will border on violent"

Andy Green sits in the lobby of a nondescript Bristolian industrial unit and mulls over the complications of driving faster than a bullet.

“Closing the throttles, the drag at that speed will be so high the car will slow down at 60mph a second – 3G. Next time you’re in a car going 60mph, think about coming to a complete standstill in one second. That’s 3G. It will be uncomfortable bordering on violent in terms of the physiological effects.

“That’s a normal day in the office for me. I’m a jet-fighter pilot. I pulled 7G with the Red Arrows last year.

“However, it’s quite a bit more challenging because it comes after a long period of acceleration when your body acclimatises to the physiological changes. If you then suddenly reverse the G over an extended period with a low blood pressure and low pulse rate you’re more prone to blacking out.”

Of all the things you might want to occur while driving at 800mph, fainting comes low on the list.

For Green – RAF Wing Commander Andy Green OBE to give him his full title – it’s just another factor to assess coolly during his “holiday job”: the attempt to set a new landspeed record in Bloodhound SSC. Why “SSC”? Supersonic Craft.

If all goes to plan, at the end of the year this extraordinary vehicle – equal parts car, jet-fighter and space rocket – will travel to Hakskeenpan, at the edge of the Kalahari desert in South Africa. After a month or so of refinement, it will streak down a 12-mile racetrack that has been hand-cleared of 16,000 tonnes of stones over seven years by volunteers from nearby shantytowns. After 4.5 miles’ acceleration it will theoretically reach 1,000mph. It might even go faster.

To understand why you need to rewind two decades.

On 15 October 1997, Green tore across Black Rock Desert, Nevada, in Thrust SSC. It was touch and go at times. So fierce was the turbulence on the jet-propelled car at 700mph that Green had to apply full right-lock. Watch the cockpit video on YouTube. His voice barely wavers – such is the steel of a RAF fighter-pilot.

Fifty years and a day after Chuck Yeager flew faster than the speed of sound, Thrust SSCclocked up 763.035mph, Mach 1.016, over a measured mileand Green became the first man to go supersonic on land.Great Britain, with its proud history of landspeed records from the 1930s, was once again the fastest nation on four wheels. Job done.

Then in the mid-Noughties, Steve Fossett, the American businessman and adventurer, mounted a credible challenge. (Though Fossett later died in a ballooning accident, other teams from the US and Australia have stepped up.) Green and Richard Noble, the former landspeed record-holder who had masterminded Thrust SSC, met in the pub to formulate a response. They decided not just to take him on, but to up the ante with a clear, memorable goal – Mach 1.5.

Even if that was later reduced to Mach 1.4 (1,050mph) – the maximum that physics allowed, advised the project’s chief of aerodynamics, Ron Ayres, developer of the Bloodhound surface-air missile (hence the name) – it’s almost impossible to comprehend such speeds on land.

No jet-fighter in history has achieved Mach 1.4 at 2,000ft, the desert’s altitude above sea level. It’s so fast that were you to fire a Magnum 357handgun at Bloodhound at full clip, the car would accelerate away from the bullet.

Green puts it another way: “It takes 300 milliseconds to blink. In that time, Bloodhound will travel 150m, the length of a football field.”

Literally, blink and you’ll miss it.

Within its industrial-estate hangar (soundtracked incongruously by Radio 2 like any backstreet garage), Bloodhound looks astonishing. Though 14 metres long, it’s compact, lean, muscular. The cockpit section behind the nose is a moulded carbon-fibre monocoque like the tub of a Formula 1 racecar. Thereafter the similarity ends. With its huge air intake and sleek aluminium body swooping to a tail fin, it resembles nothing less than a jet-fighter shorn of wings.

The cockpit – “Andy’s office” to everyone – is an intriguing mix of high and low technology. Three flat-screen computer displays sit above a panel of clunky flick-switches. The titanium steering wheel, 3D-printed to mould exactly to Green’s grip, looks like something from the Batmobile yet its triggers for the rockets and air-brakes are taken from an everyday electric drill.

What technology is better proven in a hot dusty environment?, one engineer asks.

The only everyday part of the propulsion system is a five-litre Jaguar V8 engine and that’s only installed as a fuel pump. Instead, the jet of a Typhoon fighter will provide initial acceleration before a cluster of three Nammo rockets takes over. They’re usually used to launch satellites.

Little wonder one of the knottiest problems has been how to keep Bloodhound on the ground. (Winglets on the nose and rear are the current solution.)

“[Bloodhound] is engineering without a safety net,” says Mark Chapman, chief engineer. “If there’s a problem, you’re the first to face it. There’s no handbook, no right answer. That’s why this is so appealing.”

Indeed, with no test data at these extremes, computer modelling is only so much help. Chapman adds: “We don’t know exactly what this car will do. It has 20 tons of thrust so it’ll be quick in a straight line.” He pauses. “Hopefully in a straight line.”

Green agrees nothing is certain until the rockets fire up on the desert: “There will be something unexpected in terms of handling the car but I can’t tell you what that is.”

What sort of person would take on such unknown unknowns? As Green points out: “We’ve nothing to prove. We already hold the record.” So, a thrill-seeker?

“We’re going faster than any jet-fighter has ever been,” he says. “If you gave that problem to NASA they’d spend years and enormous amounts of technology and effort and expense working out how to crack that. We’re doing it as a small tight-knit technology outfit. None of that says thrill-seeking to me.”

A petrolhead, then?

“Ish. I might read Autocar if I’ve finished Flight magazine.” His passion when not going supersonic is sailing, a sport in which he probably averages 10mph.

No, Green is – and I mean this as a compliment – a geek, albeit one with nerves of steel and a willingness to fly into a war zone if required; his last campaign was over Libya in 2011.

When we meet he’s dressed in a crisp shirt, pressed khakis and chunky boat shoes. In conversation he’s more Mr Spock than Maverick from Top Gun. He’s precise, pragmatic, analytical (he got a First in mathematics at Oxford), with a crisp manner that suggests he doesn’t suffer fools.

He’s at his most animated when he shows me over the “engineering adventure that is Bloodhound”; pointing out details like the U-shaped rims on the aerospace-grade aluminium desert wheels, for example, or extolling the engineering that overcame similar resonance frequencies between the tail-fin and air-brakes.

It’s not the why of Bloodhound that intrigues him. It’s the how. “We’re racers, albeit very scientific racers, racing against the limits of physics,” he says.

“I’m going to avoid the word ‘safe’ because this is so challenging, but Bloodhound is a risk-managed car. You work out the challenges, work out what you have to do to deliver the effect safely and work out what you have to do deliver them to the lowest practical risk.”

And there are definitely risks. If the computer modelling is accurate, below 200mph the wheels provide grip. Above 600-700mph, there’s aerodynamic grip. Between them? Well, things could get hairy.

“Aerodynamically and dynamically, the car’s stability is at its lowest from 300-400mph. The wheels are now planing – they’re only penetrating 2-3mm into the surface – so the car will go from predictable handling at 200mph to all over the place at 300-400mph. That’s also when we fire the rocket. So, we’ll be accelerating at 40mph per second with almost no grip, as if we’re driving on ice.”

The challenge is to know how just far you can push. “Because we have to keep this car shiny side up. At the end of the day, our story is about how cool science and technology is for a 12-year-old.”

Bloodhound may be a flagbearer for British innovation, but its official raison d’être is to inspire. In 2007, Lord (Paul) Drayson, Minister of State for Science and Innovation, flatly turned down Green and Noble’s request to borrow a Eurofighter jet engine for a landspeed attempt. But a project that could inspire the next generation of British engineers as Concorde had in the Seventies? Why not?

That’s why all project data is available online (the website is fascinating for amateur engineers); why feedback from Bloodhound’s 12 high-definition cameras and 500 sensors will be streamed online in South Africa. “Our engineers won’t be analysing that live, they’ll be running the car,” Green says, “which means there’s a whole generation – tens of millions of kids – who will get to see that data before we do. That’s not something you do in conventional motorsport.”

Ironically, it’s this not Mach 1.4 that gives him the jitters. “I know what landspeed records are. I know what supersonic looks like. I understand jet engines. A global education programme? Even the guys in education have no idea.”

Certainly, the pressure is on. The public response to Bloodhound has been astonishing. Its YouTube videos have received over 15 million hits. The project has netted over £1bn in advertising value equivalent through coverage in press as diverse as the Financial Times and The Beano. And when the car made its debut in London’s Canary Wharf last September, the 8,000 public tickets sold out in two hours.

Not bad for a car that hasn’t even run yet.

So, it seems particularly tough that Bloodhound, though kick-the-tyres ready, was on hold due to lack of funding when I visited in spring. Despite corporate sponsors and nearly 30,000 public donations in return for a name etched on the tail fin, a £7 million shortfall had postponed the preliminary track tests on a Cornish airfield until autumn.

Off the record, a team-member admits to frustration that, having cracked the physics, the hold-up is over a sum found down the back of Branson’s sofa.

Publically, Green is as confident the money will arrive as he is that this nimble British team will crack 1,000mph. He is a very singular breed of adventurer; one who deals in logic not romance or swaggering machismo. Isn’t there a part of him enthralled by the pure endeavour of the feat?

“Yes, of course. But it depends what feat you’re talking about. Mine is the challenge of managing not only the technical assembly of this prototype vehicle, but the management of the campaign very safely in a difficult desert, repeatedly and in full view of a global public who you tell in advance what you hope to do and who get to mark your homework live, so you can’t make something up. That’s a fascinating opportunity.”

Alongside all of that, the possibility of blacking out at 800mph becomes just a minor inconvenience.