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TheForce of Nature, as the bike is known, hit top speeds of roughly 290km/h (180mph) at Elvington Speed Week in May. Controlled by Sykes, it managed 263.6km/h (163.8mph) in just 3.87 seconds over one-eighth of a mile, breaking the world speed record for a steam-powered motorcycle – and it is yet to reach full power, Sykes claimed.
The previous record was set by American inventor Bill Barnes, who hit 129.6km/h (80.5mph) on a wheel-driven bike in 2014. Sykes managed such a huge increase by going with a thrust-driven design instead, he said.
“I don’t want to take credit away from Bill Barnes, because a world record of 80mph is phenomenal,” said Sykes. But, he added, “it’s so inefficient when you start having rotating parts, reciprocating parts… we don’t have any of those parasitic losses”.
Phenomenal acceleration
Rather than using a motor to turn the wheels, the Force of Nature uses the latent energy of superheated, pressurised water, which is then released through nozzles. This turns to steam, thrusting the bike forwards.
A ‘docking station’ with a small 20kW burner running on hydrogenated vegetable oil provides the heat, with hot gas directed through a manifold and into six burner tubes with added turbulators. The tubes run through the pressure vessel containing up to 100 litres of water, which reaches temperatures of up to 250ºC and pressures of 40bar (580psi).
The bike can then be removed from the dock and lined up at the start of a run. Sykes gets on, opens the safety valves and prepares to go. When he is ready, he presses a button to release the second set of valves. Water accelerates to about Mach 1.1 as it rushes through two de Laval nozzles, where it turns to steam and generates huge amounts of thrust.
“It’s exhilarating,” said Sykes. “Somewhat daunting just before you press the button – we’re seeing up to 3.5G acceleration, so it certainly demands a lot of concentration.
“But the bike itself handles very well, because its centre of gravity is low and it’s quite long. All you’ve got to do is just move your head from side to side, and the thing just tends to guide yourself that way.”
He added: “As soon as you set off, the acceleration is phenomenal, but it just gets quicker and quicker the lighter it gets, because the power-to-weight increases the lighter the bike becomes, which is unlike anything else. It’s almost like being on the end of an elastic band. And then you can feel the bike getting lighter, it’s more responsive, and then you can feel the power just petering out and then you’re coasting.”
Full speed ahead
大自然的力量是很多,但是实用vehicle it is not – it takes four hours to heat up on the dock, making it unsuited for a quick trip to the shops. It seems unlikely that Sykes’ success will encourage hordes of copycats.
“When I first started the project, I thought this would be fairly straightforward – it’s just a pressure vessel, some valves, an outlet, and a delivery nozzle,” he said. “It’s turned out to be the hardest project I’ve ever undertaken.” The team, which also includes Sykes’ wife Diane as financial director and purchaser, has now set its sights on accessing more of the 58% of untapped power. They aim to beat their own record by becoming the fastest steam-powered vehicle ever, and surpassing 200mph in the standing one-eighth mile.
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