Yesterday I took the decidedly subsonic train up to central Coventry to meet the fastest ground-level human on the planet.
RAF Wing Commander Andy Green holds the world land speed record - a supersonic 763.035mph in Thrust SSC on 15 October 1997 in the Black Rock desert in Nevada. Not only that, he also holds the diesel-fired land speed record - 350.092mph in the JCB DieselMax on the Bonneville Salt Flats on 23 August 2006.
The rendezvous was at Coventry’s Transport Museum, which is currently undergoing a revamp. A new display room houses the last two British land speed record holders - Thrust 2 (which hit 633.468mph in October 1983) and Thrust SSC - together with the new Bloodhound SSC.
If everything goes to plan, Bloodhound - which will also be piloted by Andy Green - will have hit 1000mph on a South African desert by the end of the year or early in 2016.
You might think, as I did, that Green is the UK’s go-to land speed record pilot because of his background flying Phantom and Tornado jets for the Royal Air Force. That’s obviously part of the reason, but he also happens to be a maths whizz. The sort of whizz who got a first in his Mathematics degree at Worcester College, Oxford.
I like to dig into a vehicle’s engineering, but talking to Green about the design of the Bloodhound was a wholly different experience to the average automotive technical briefing.
Judging by the conversation with Green, trying to run a wheeled vehicle - powered by both a jet engine and a three-bore rocket - up to 1000mph and stopping it again requires a huge grasp of higher-level physics and maths.
Green tears into explaining the huge engineering challenges with rapid-fire reference to fundamentals you might vaguely remember from school.
Indeed, I heard him use the term ‘the area under a curve’ when taking about the calculations they needed to do when working on slowing the Bloodhound down. It’s the first reference to that concept I’ve heard since my ill-fated attempt at O-level maths in 1983.
But Green’s contribution is not just about a fundamental understanding of the physics of challenge. He’s also the best person in the world to advise on the design of the Bloodhound because of his experience with Thrust SSC.
Safety-critical areas such as the steering stability, the ability of the suspension to cope with minor dips in the desert surface (which could translate into a 30 tonne loading on the components) and how to keep the rear wheels on the ground (the rear of Thrust SSC famously lifted off), benefit massively form Green’s input.
He is, of course, the only man on earth who has experienced driving beyond the speed of sound. Perhaps his key experience in Thrust SSC was what he described as ‘hitting a wall’ as the vehicle made its 763mph maximum.
Bloodhound’s engineers named the phenomenon ‘spray friction’. As the Thrust SSC accelerated, a huge shockwave was created under the car, which ‘exploded’ the surface of the desert. The resultant plume of debris thrown up caused huge drag around the rear end of the car, preventing it from gaining more speed.