Practical Sportsbikes (UK)
Less bodywork could be the key to Guy Martin’s 300mph speed attempt
Guy’s ’busa in a wind tunnel. We thought wind was the problem. What do we know?
Imet this fella called Rob White at Elvington a while ago, he’s building this mad electric bike to try and set the record for the world’s fastest electric motorbike. We kept in touch, then one day he popped up and asked if I want to go halves on a day with him at the wind tunnel at MIRA (Motor Industry Research Association, Nuneaton, Warks) because he wanted to confirm his simulation numbers. So, we did half a day with his bike, and half a day with mine.
After I tried mine fully-faired (getting a figure of 0.44Cd) I thought I’d try it without any bodywork, and it was 0.75Cd. Considering the stock Hayabusa was claimed to be the most aerodynamically efficient bike with a Cd of 0.6, it made me think if I binned the tail unit, the Cd would probably still be 0.5 or 0.6 – and it’d be easier to ride.
I was asking all the fellas at MIRA for advice, but no one was saying anything other than you’re trying to do something that’s never been done, and all we can do is give you the numbers. So, I reason the tail unit makes the side area so big and sensitive to side winds, that while it’s probably OK at 300mph, at the moment it’s stopping me get near 300mph because it’s hard to ride.
Rob was adamant that I need to keep the Cd down, and the centre of pressure as far away from the centre of gravity. I said that I’ve got the numbers, but this is the road I think I need to go down; a higher Cd, but mask that problem with a wheelbarrow-load of horsepower. So we’ll see how much, if any, easier it is to ride at more than 250mph with less bodywork.
I’ve fitted an OE seat unit, ditched the bottom half of the fairing, and we’re at our usual Rutland runway – in less than ideal conditions. After a handful of runs, the datalogger showed that in conditions in which I previously wouldn’t have taken the fully-faired bike out
of the van, I did three runs at well over 250mph.
It’s so much easier to ride, it makes the window of opportunity to go very fast much bigger. This has just proved that I’ve got to do my own thing, I’ve got to stop being distracted by what everyone else is doing. They’re all clever people, and they’ve all been doing it a long time, but I need to start trusting my own instincts, and I’m doing alright. I’ve got to get the f**ker done.
I’ve hit all my goals for this year and finished quickest this year [286mph is Guy’s best so far]. It’s been a really good year, I’ve gained 10mph from last year, and now I know that my bike is so much easier to ride fast more of the time. The more I can ride it, the better the chances of getting to 300mph first are.
Now I’m looking at what Voxan did with Biaggi on their electric bike, and that was only their third time out, and they’re already at 254mph. I’ve made my bed now by using an internal combustion engine, and I’m lying in it, so I’ve just got to do 300mph before they do. I don’t care how you class it, whether its petrol, electric, methanol or pig sh*t, 300mph is 300mph.
It did take the wind out of my sails when I heard about Biaggi. But getting from 250mph to 270mph is a massive jump. I know, because I’ve done it. Ironically, I’m also eco-friendlier than all electric bikes because I’m running e85 fuel (typically 85% bio-ethanol).
Shane Stubbs, with his big fairing, did 260mph, but 278mph semi-naked, and there’s another American team that’s built a bike with a massively complicated set-up with a low pressure turbo in the headstock, then a high pressure turbo where mine is. The low pressure turbo blows the inlet side of the high pressure turbo, plus the exhaust gases still drive the high pressure turbo. The thinking and engineering is a real testament to Bill Warner’s ingenuity. They’re also after 300mph, but they’re still at 253mph.
I’m nearly back to where I started with the aero package. When I got the turbo engine from Jack Frost, it did 257mph in road bodywork. Learning isn’t always about understanding what works, but more often figuring out what doesn’t. Roll on 2021.