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Better aerodynamics puts record in sight, but makes take-off tricky

Graeme Obree has made dramatic changes to the Beastie supine recumbent that he plans to use in September for a crack at the human-powered land speed record, with a new fairing to make the bike even more aerodynamic.

In testing back in November, Obree realised that the previous two-piece shell was not as slippery as it could be, and went back to the drawing board, according to Leo Kent’s latest update on Humans Invent.

Smooth curves

Obree said: “The front section is rounded, then it widens out and widens out and then comes back in, in a very smooth curve and narrows down to the back end…the most important part in terms of dividing the air and then pulling the air back in again with the least amount of energy is to have a laminar (non-turbulent) flow over the sides of it.”


Image: Rick @ Cyclesportphotos.com

The biggest remaining problems with the Beastie are geting it started and seeing where you’re going. The bike needs a push start because there is no way for Obree to support himself at a standstill, but the new shape is so narrow and slippery that it’s hard for his helpers to get a grip.

“I wanted to go at a great speed right away but the guys couldn’t launch me,” said Obree. “Back when I tested it at Machrihanish airport, I only needed one person to launch it so I assumed it wasn’t that hard to keep me upright and push me in a straight line but because it’s now all slippery and fish-shaped it’s hard for them.”


Image: Rick @ Cyclesportphotos.com

The tests at Machrihanish resulted in Obree cutting a larger hole in the the fairing so he could see where he was going, but if the road surface isn’t perfectly smooth, vision is still a challenge.

“The rattling goes right into your head because you’re so close to the ground,” he said.

Visibility

In the most recent tests at Prestwick Airport, Obree didn’t get anywhere near the speed he will need to hit when he goes for the record in Nevada. Because he couldn’t see very far ahead, it was hard to gauge the remaining runway.


Image: Rick @ Cyclesportphotos.com

“When you are 2ft 6in off the ground you can’t see how much runway you’ve used so I never actually got to my max speed. Also, you’re over geared because it is really geared to be doing 80 or 90mph.”

83mph

Nevertheless, one record that looks to be within easy reach is Jason Queally’s British mark of 63mph. Sam Whittingham’s 83mph record will be rather harder to crack.


Image: Rick @ Cyclesportphotos.com

“To go at that speed, and Whittingham is no slouch as a cyclist either, you’re thinking, I have to respect this record, it’s not going to be easy to break. I hope I can but I haven’t gone at any great speeds yet, so really you know as much as I know.”

Graeme Obree quotes courtesy of Human Invent, which also kindly supplied the pictures taken by Leo Kent.

Here's the new Beastie in action

Our official grumpy Northerner, John has been riding bikes for over 30 years since discovering as an uncoordinated teen that a sport could be fun if it didn't require you to catch a ball or get in the way of a hulking prop forward.

Road touring was followed by mountain biking and a career racing in the mud that was as brief as it was unsuccessful.

Somewhere along the line came the discovery that he could string a few words together, followed by the even more remarkable discovery that people were mug enough to pay for this rather than expecting him to do an honest day's work. He's pretty certain he's worked for even more bike publications than Mat Brett.

The inevitable 30-something MAMIL transition saw him shift to skinny tyres and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.