Breaking the human-powered bicycle speed record requires new designs 17 MAY 12 by ROBIN HAGUE Graham Obree This article was taken from the June 2012 issue of Wired magazine. Be the first to read Wireds articles in print before theyre posted online, and get your hands on loads of additional content by subscribing online. Graham Obree wants to ride his bicycle -- at a speedy 160kph, or 100mph in old money. Its a question of working out what the laws of physics allow, given the power you can produce, says Obree, based in Ayrhshire, near Glasgow. If everything was perfect, with the power output and aerodynamic drag, then [160kph] might well be possible. This September, Obree will saddle-up his self-designed bicycle on Nevadas State Route 305 and start pedalling. The current human-powered world speed-record is held by Canadian Sam Whittingham, who reached 142kph. Obree will have a 6km run-up to get up to speed, before his attempt to beat Whittingham is timed over a 200-metre stretch. Human power is limited: Obree will have to get his bike (called Pie in the Sky) up to motorway speeds on less than 1kw (about one horse-power). Aerodynamic drag is the dominant constraint on top speed, so record contenders generally sit in a reclined position down between the wheels. Obree, 46, is taking a different approach: The bike is only 82cm tall and I will be pedalling it head-first, instead of reclining, looking just over the front wheel. This gives the minimum possible cross-section. Obree has also designed two stages of chains and gears; otherwise the chain wheel would have to be more than one metre across to achieve a high enough gear ratio at top speed. The man has form: during the 90s he rode several bicycles of his own design to world records and pioneered two new riding positions -- which were banned by the Union Cycliste Internationale. He briefly moved into professional cycling, but says it wasnt for him: Where cycling as a sport is very restricted, the land speed record offers free expression for innovation. Edited by IAN STEADMAN
Posted on: Thu, 31 Oct 2013 04:30:35 +0000
Trending Topics
Recently Viewed Topics
© 2015