Sunday, 4 October 2009

Developing a cutting-edge human-powered vehicle

By Julian Edgar

This is Part 1 in the third series we’ve done on building alternative, pedal-powered road vehicles. So why do we keep covering these vehicles? Here are the reasons:


Vehicles of this type are amongst the most innovative that you’ll find on public roads. The construction and suspension designs are cutting edge for ultra light-weight, good-handling and extraordinarily comfortable vehicles. I choose to use human power to propel them, but exactly the same underlying philosophies apply even if the power-plant is electric, diesel or petrol.


A human-powered vehicle (HPV) is able to be used on public roads without the legal difficulties that apply for every other innovative vehicle design. You might have a concept for a car powered by a steam turbine, or one that uses a petrol engine but has the wheels arranged in a diamond-shaped wheelbase pattern. But no matter how good it is, getting it legally registered on the road is likely to prove both expensive and difficult.


This type of vehicle can be easily home constructed. You don’t need large facilities; you don’t need expensive gear like metal shears or metal benders. In fact, if you get someone else to do the welding, a vehicle like this can be constructed with just hand tools. If you buy an oxy-acetylene welding set-up, you can do everything yourself.


Finally, I find the design and construction of such a vehicle a fascinating exercise, fearsomely complex and challenging. No-one, no matter how experienced in engineering, finds designing a vehicle of this type easy. As just one example, a rear suspension assembly (one that might need to support a dynamic maximum of 150kg) may have a required mass – including spring, damper, arm and pivot points - of less than 2kg. To put this another way, it has to be able to support a load 75 times its own weight. Think about that for a few seconds…

Read the article here:

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