Quote:
Originally Posted by freebeard
www.bikeboom.info/efficiency/: How the bicycle beats evolution and why Steve Jobs was so taken with this fact
Quote:
“When one compares the energy consumed in moving a certain distance as a function of body weight for a variety of animals and machines, one finds that an unaided walking man does fairly well (consuming about .75 calorie per gram per kilometer), but he is not as efficient as a horse, a salmon or a jet transport. With the aid of a bicycle, however, the man’s energy consumption for a given distance is reduced to about a fifth (roughly .15 calorie per gram per kilometer).
“Therefore, apart from increasing his unaided speed by a factor of three or four, the cyclist improves his efficiency rating to No. 1 among moving creatures and machines.
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Yes, a really important citation. And what if we gave a bike decent aero drag, and a recumbent position to reduce frontal area?
About 15 years ago I fell in love with recumbent trikes - most of the efficiency of a bike, but with vastly more comfort and stability.
In short:
... I rode a Greenspeed recumbent trike...
... loved it...
... bought a secondhand one...
... felt I could do better...
... found I couldn't...
... designed and made another...
... got closer...
... designed and made another...
... was getting better...
... designed and made another - and was mostly happy.
I didn't do any aero at all (we then lived in Queensland - think Florida for climate), and no canopy would have been bearable.
But I remember my initial absolute arrogance - how I was just soooo going to improve on the Greenspeed (little did I then know that the late Ian Sims was one of the very best engineers I've ever met) because I just knew about
proper design like suspension. After years of development, I got to the point of shaving anti-roll bar brackets for reduced mass - every gram was so critical. But it did have what I think was probably the best pedal vehicle ride comfort in the world.
It was fun, and a great engineering exercise. It was also a bit like on this group: the main recumbent discussion group in the US very soon became cross with me when I challenged their longstanding, prevailing wisdoms. What prevailing wisdoms? Boom flex, ride comfort, construction techniques, handling assessments, etc.
They kept on insisting their trikes handled so well, and in the end I did a simple circular skid pan test that easily showed maximum sustainable lateral g's. Certainly not the be-all and end-all of handling, but a comparison starting point. To do well, you had to be able to pedal hard, hold the steering line, and go fast. One guy, who had a tilting trike, was going to smash me. It was very interesting - I waited with great anticipation. Then nothing happened. (Looking at his machine, I think he couldn't pedal at the required steering lock.)
Some investor heard about my projects and sent his expert to ride one of my recumbent trikes. It was very weird. The guy plunged down my local hill at full speed and then yanked on maximum steering lock. Not surprisingly, the trike did a barrel roll...
I also built a long wheelbase, full air suspension recumbent bike (not trike), but I hated it.
But now I am mostly into bikes, like my Moulton.
And I wrote a book on small wheeled bikes, but almost no-one has bought a copy!
But if you want engineering at its absolute purest, no rules and no restrictions, pedal-powered bikes and trikes are it.
(And a last pic - my first trike. Far too heavy - the start of my learning curve!):
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