Race to 400mph: why land speed record barrier took decades to crack

Sixty years on from Breedlove becoming the fastest man on earth for the very first time, it’s interesting to see why 400mph seemed such a difficult barrier to break, while 500mph and 600mph were so comparatively easy.

Of course that first run of his was not a land speed record as such, as to comply with the FIA’s then-definition of an eligible vehicle required a car with four wheels and to be driven by at least two of them. His Spirit of America was a jet-powered three wheeler. The only land speed record set above 400mph and recognised as such at the time was the 403mph achieved by Donald Campbell in his wheel-driven, four-wheeled Bluebird-Proteus CN7 at Lake Eyre in Australia, 11 months after Breedlove had done 407mph. So while Campbell was undoubtedly the LSR holder, he was never the fastest man on earth.

The requirement for land speed record vehicles to be wheel-driven was dropped in 1964. The interesting thing is, to this day, while the outright LSR is the same 763mph achieved by Andy Green in Thrust SSC at Black Rock desert on October 15, 1997, the wheel-driven record has risen by just 53mph to 458mph, set by Don Vesco in his ‘Turbinator’ at Bonneville in 2001. Indeed only once has 500mph ever been achieved by a car driven by its own wheels, a speed reached by 76-year old Dave Spangler in ‘Turbinator II’ at Bonneville in 2018. But it was a peak, not an average speed and in one direction only, both of which disqualifies it from official record holding status.

So what makes a wheel-driven 400mph so damn difficult? Let’s look in the other direction: in the 1930s, the LSR advanced steadily thanks to the efforts of three great Britons, Sir Malcolm Campbell, George Eyston and John Cobb. On the first day of the new decade it stood at 231mph, on the last some 367mph. Then, to be fair, a global conflict got in the way so it would be 1947 before Cobb could take his monster Railton Mobil Special out of mothballs and raise the mark to 394mph becoming, I should say, the first person to break 400mph on land, if not set a record above that speed.

Who’d have thought it would take so long for those last few mph would be added? When Cobb set the record in 1947 no one had even flown faster than the speed of sound; by the time Campbell raised his record by just 9mph, 11 men and one woman had already been into and returned from space.

The reasons for this, however, are not difficult to understand. Huge speeds require not just huge power, but minimal drag too. But the problem encountered by Cobb and co is that even the more beautifully rendered teardrop body shapes presented an enormous frontal area when, as was the case with his car, it had to house two 26.9-litre, supercharged, twelve-cylinder Napier Lion aero engines. Of course Donald Campbell’s solution to that was to use a long, slender gas turbine instead, but that only addressed one of the problems.

There were of course frictional losses in the transfer of power from engine to driven wheels, but the bigger problem was what to do with that power when it arrived because, when it comes to traction, a salt lake is like a skid pan compared to any normal surface upon which a car might regularly drive.

Which is where the perpetual enemy of all those who crave a land speed record rears its ugly head: geography. The Bonneville Salt Flats are the temple of record breaking on wheels but they offer only around 12 usable miles at the best of times and often quite a lot less. Now remember that your speed is averaged through one measured mile and you can’t put it right at the end of the run where you’ll be going fastest because you have to use the same measured mile on the return. So it has to be slap in the middle. Now imagine trying to give the four tonne, 4000 horsepower Bluebird the beans off the line on that surface on the skinniest tyres that would handle the speed. Even with four wheel drive (which Cobb had too), it’s hard to imagine being able to put your foot hard down.

Jet engines solved all of this. They were aerodynamic, were attached to no transmission system so were hugely efficient and required no traction whatever as their wheels were undriven. Best of all however they allowed for an amount of power to be deployed no piston-engined nor any wheel-driven machine could imagine deploying on salt. While Campbell’s Bluebird-Proteus CN7 did indeed develop around 4000bhp, this figure is dwarfed by the over 100,000bhp used to push Andy Green through the sound barrier in 1997 at almost double the speed achieved by the Bluebird just 34 years earlier.

But now geography is preventing cars going faster again because even jets with six figure horsepower outputs take time to accelerate. So it seems the only way anyone is going to raise the mark further still is with rockets to gain speed in the shortest possible period of time, then a jet to maintain it through the measured mile. This was precisely the thinking behind Bloodhound SSC before financial problems engulfed it. And of course, when it comes to breaking the land speed record, that is the biggest problem of all: whether it be powered by pistons, jets or rockets, if it’s not got the funding to go with it, your LSR car stays parked.