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Armoured bike
Posted: Tue Oct 20, 2009 8:35 am
by Talbot
I thought you would get a kick out of this. It is an awesome hoax!
http://riowang.blogspot.com/2009/05/in- ... ertas.html
Posted: Tue Oct 20, 2009 11:57 am
by Donal Mac Ruiseart
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Posted: Tue Oct 20, 2009 12:22 pm
by Kilkenny
I found it amusing.
Posted: Wed Oct 21, 2009 5:27 am
by J.G.Elmslie
brilliant.
well done, too.
and a (very broken) part of me that has fond memories of plummeting down mountainsides at 60mph is now wanting to work out how much extra protection steel plate would give over kevlar.
Posted: Wed Oct 21, 2009 2:28 pm
by Baron Alcyoneus
It would have been even better if they'd included Leonardo da Vinci's very real design for a chain...

Posted: Wed Oct 21, 2009 5:01 pm
by Konstantin the Red
If only dear old Leonardo had thought to include a sprocket... but that shape of gear was centuries in the future. They might have invented the safety bicycle in the sixeenth century!
[So called because falling off of one wasn't quite the vertiginous plunge that falling off a penny-farthing was. And you could just stabilize by putting a foot down.]
I'm assuming they wouldn't have had the pneumatic tire, though. The ride would have been a real tooth-rattler at speed, not just a "boneshaker" until a good seat cushion had been devised.
Posted: Thu Oct 22, 2009 7:41 am
by Donal Mac Ruiseart
I had a brief thought about using whalebone for springs . . .
Posted: Thu Oct 22, 2009 8:04 am
by Baron Alcyoneus
Konstantin the Red wrote:If only dear old Leonardo had thought to include a sprocket... but that shape of gear was centuries in the future. They might have invented the safety bicycle in the sixeenth century!
http://www.odec.ca/projects/2007/viva7s2/cvts2.htm
The continuously variable transmission (CVT), although a pretty new innovation to the car industry, the idea has been around since the 15th century when Leonardo Da Vinci sketches his version of a stepless continuously variable transmission.

Posted: Fri Oct 23, 2009 11:45 am
by Vermin
I once rode a wooden bicycle made from DaVinci's plan, no added safety features or comforts.
Let's just say it rode a little rough.
And trying to stop or turn?

Posted: Fri Oct 23, 2009 12:32 pm
by Mac
Baron Alcyoneus wrote:http://www.odec.ca/projects/2007/viva7s2/cvts2.htmThe continuously variable transmission (CVT), although a pretty new innovation to the car industry, the idea has been around since the 15th century when Leonardo Da Vinci sketches his version of a stepless continuously variable transmission.

Look again carefully at the drawing. It is *not* a continuously variable transmission. It is a transmission with six discrete ratios.
Turning the crank at the bottom of the frame allows the any of the six idlers on the common shaft to engage the pinion. Further, a worm gear on the selector shaft moves the drive barrel left or right to maintain the correct engagement depth.
Although ingenious, it would not work as drawn. There would need to be some way of stopping the drive barrel while changing gears. Otherwise the spring would wind down unchecked while the "great wheel" was in between idlers. Also, meshing with the next idler could not happen while the power was still being applied.
Leonardo may well have drawn other mechanisms which have continuously variable ratios. but this is not one.
Mac