martes, septiembre 11, 2012

Obree , 160km/h en bici ? /3 bicis originales

Cycling legend Graeme Obree hopes his latest innovation will not only break the human-powered vehicle land speed record, but also break through the 100-mph barrier (Photo: Humans Invent)

INVENTORS AND REMARKABLE PEOPLE.Flying Scotsman's "Beastie" to be first human-powered vehicle to achieve 100 mph on the flat?

By James Holloway.September 10, 2012

Scottish cyclist Graeme Obree is building a special sort of bicycle. He's building it in his own kitchen without a lick of research assistance to inform the design. Why might research assistance be useful? Because with this bicycle, dubbed Beastie, Obree intends not only to break the human-powered vehicle land speed record, but also hopes to be the first person to break 100 mph (161 km/h). But then, Obree's never been one to do things the easy way.

Which isn't to say Obree's an underdog. He has form in both building his own bicycles, and then riding them. Fast. In 1993, then unknown, he became the man to travel farthest in a one-hour period (51.596 km or 32.060 miles), and in 1994 he did it again (52.713 km or 32.754 miles) having seen his record broken by Chris Boardman in the interim. He recorded the first feat on a self-built bicycle, Old Faithful, which famously used bearings taken from a washing machine. These achievements led to his nickname, The Flying Scotsman.

Old Faithful demanded an apparently ungainly riding style thanks to its handlebars being located much closer to the saddle. These would sit under Obree's chest, his arms tucked in by his sides. It may have looked peculiar to the casual observer, but the technique afforded marginal aerodynamic advantages, which, combined with his willingness to push his body beyond its limits, led to record-breaking performance. Cycling authorities banned the riding position soon after.

Obree actually failed his first attempt in 1993, but was allowed a second stab the following day having booked the velodrome (Hamar in Norway) for 24 hours. To prevent his muscles from seizing up entirely in between attempts, he took the remarkable step of drinking large quantities of water, physically forcing himself to wake up in the night to visit the bathroom, stretching his muscles in the process. He'd reportedly hardly slept at all before his second attempt the next day. "I was a different animal," he later told The Telegraph. "The day before, I'd been a mouse. Now I was a lion."

Between 1993 and 1997 Obree won numerous events and titles, including the individual pursuit world championship in 1993 and 1995. He'd adopted a new riding style by 1995, dubbed Superman due to the arms-first position adopted, though this was also subsequently banned. A professional cycling career was cut short after a falling out with the team manager at Le Groupement, and later, he says, his refusal to go along with doping. All of which is to say nothing of the considerable adversity Obree has faced in his personal life.

In 2012, in the days leading up to his 47th birthday (on Tuesday), Obree has again been doing things the hard way. This time he's building a prone bicycle, which isn't unusual for the land speed record. That he's eschewing external help is hardly surprising either, given his history in the sport, but there are other obstacles to overcome. Not least of these is missing the window for a scheduled meet at Nevada's Battle Mountain because the bike, Beastie, you'll recall, isn't quite ready.

Now Obree has the task of finding an alternative venue in the UK, preferably an airfield with a 2-mile runway made of fast tarmac, with no joins or blemishes. But this means doing without some of Battle Mountain's luxuries: a 6° gradient in the rider's favor and a 5000-ft (1500-meter) altitude, reducing drag. "In an engineering journal I read, they said that Battle Mountain is worth 156 watts extra in energy," he told Humans Invent. "And that is just the slope. Then the surface is actually purposefully built for the record attempt, so that has to be worth another fraction in terms of surface resistance." Though Beastie is yet to be completed, Obree says he's "really happy" with its aerodynamics. In fact, the bike in general is every bit as innovative as Old Faithful. Critical to the design is a compact frontal area, which necessitates an incredibly contained riding style. He claims this is one of the smallest bikes every created as far as frontal area goes.

"The feet just miss each other on the way past which means the width at the back is the minimum possible so the vehicle can be tailed of short," Obree told Humans Invent "Also it means the knees are closer together and partially share the same space at the bottom of the stroke which means that the skin can be tucked in closer, and that means less frontal area."

This sacrifices the direct drive of the rear while, necessitating a series of chainwheels—the theory being the loss in efficiency in the drive mechanism will be more than offset by the aerodynamic advantage. And the pedaling action isn't circular, but a push/pull arrangement which, as Obree said, reduces the need for the rider's knees to dip, also boosting the aerodynamics.

Perhaps the most eye-catching feature of Beastie is its clear skin, and for this Obree did receive some outside help: from The Glasgow School of Art. He says he wants people to "see the engine," by which he means the rider.

It sounds like only tweaks remain to be made. A shoe-plate here, an elbow guard there: potentially crucial tweaks when seeking to break 100 mph, to be sure, but nothing that affects the principle behind the bike. A time and place for the record attempt are yet to be confirmed, but there's a limited window before the British winter sets in.

"To be honest, I am happy it will be a British attempt now. Designed in Britain, made in Britain and broken in Britain," Obree told Humans Invent. "This also means that we can go for the world human-powered land speed record, and also the British human-powered land speed record."

Of course whether he will crack the 100 mph mark, or even the record, remains to be seen. But he's clearly set his mind, and, more importantly, his will to the task, and that usually means only one thing. I certainly wouldn't bet against him.

In the video below, Obree talks to Humans Invent about breathing. Clearly, Obree's as keen to refine human performance as he is bicycle performance.

http://www.gizmag.com/graeme-obree-100mph-bicycle/24073/

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The Amphibian Bike concept is the work of Chinese designers Bin Yu and Jian Wang, and in our book, is probably the design with the greatest potential for humanity among the strong field. The big difference with this bike compared to all the other amphibious bicycle designs we have seen is that it can be used as an ordinary bicycle on land. When used on water using the inflatable wheels which fit inside the existing wheels are inflated. The Shuttle Bike is still the best amphibious bike we have seen, though the weight overhead when on land is significant.

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URBAN TRANSPORT.Bike-pack: the bicycle that folds into a backpack

By Loz Blain.July 9, 2008

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URBAN TRANSPORT.NeilPryde Bayamo bicycle targets time trial riders and triathletes

By Darren Quick.September 3, 2012

The partnership between BMW's DesignworksUSA and NeilPryde that began in 2010 with the Alize and Diablo high performance road bikes has yielded its latest design. The third line of frames resulting from the partnership are the new Bayamo and Bayamo+, which take on board concepts developed and tested on the earlier models. Aimed at time trial athletes and triathletes, their creators say the bikes are lightweight and high strength, with “wind-cheating aerodynamics.”

Named after a Caribbean coastal wind, the Bayamo’s unidirectional C6.7 carbon fiber frame is the result of computational fluid dynamic analysis and wind tunnel testing. Side on, the frame appears quite substantial, but it is revealed to be exceptionally thin when viewed front on. This is to minimize wind resistance and increase aerodynamic performance for time-trial cyclists for whom every split second counts. The “Kamm” tail aerofoil found on previous models has been truncated to deal with the wider yaw angles of up to 30-degrees experienced during time trials and triathlons.

Further enhancing the bike’s clean lines are the routing of all the drivetrain and shifting cables inside the Bayamo’s frame. The bikes also get an exclusive dropout mechanism that it is claimed enables precise positioning of the rear wheel, while the Bayamo+ gets a new proprietary QFit stem design that is adjustable for both height and ride angle. The maker’s say the bottom bracket where the cranks and pedals meet the frame has also been made exceptionally stiff to ensure the rider’s energy is more efficiently transferred.

The Bayamo frameset, including frame, forks, seat post, and headset, is available now for US$2,750, while the Bayamo+ frameset, which adds the QFit stem and fully integrated brakes, will be available in 2013 for $5,000. Adding a Shimano groupset, Mavic wheel, and other premium components sees the prices rise to the $3,095 to $10,000 range.

http://www.gizmag.com/neilpryde-bayamo-bike/23971/

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