Armoured bike

Talbot · Post by **Talbot** » Tue Oct 20, 2009 8:35 am

I thought you would get a kick out of this. It is an awesome hoax!

http://riowang.blogspot.com/2009/05/in- ... ertas.html

Donal Mac Ruiseart · Post by **Donal Mac Ruiseart** » Tue Oct 20, 2009 11:57 am

.

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Kilkenny · Post by **Kilkenny** » Tue Oct 20, 2009 12:22 pm

I found it amusing.

J.G.Elmslie · Post by **J.G.Elmslie** » Wed Oct 21, 2009 5:27 am

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.

Baron Alcyoneus · Post by **Baron Alcyoneus** » Wed Oct 21, 2009 2:28 pm

It would have been even better if they'd included Leonardo da Vinci's very real design for a chain...

Konstantin the Red · Post by **Konstantin the Red** » Wed Oct 21, 2009 5:01 pm

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.

Donal Mac Ruiseart · Post by **Donal Mac Ruiseart** » Thu Oct 22, 2009 7:41 am

I had a brief thought about using whalebone for springs . . .

Baron Alcyoneus · Post by **Baron Alcyoneus** » Thu Oct 22, 2009 8:04 am

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.

Vermin · Post by **Vermin** » Fri Oct 23, 2009 11:45 am

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? :shock:

Mac · Post by **Mac** » Fri Oct 23, 2009 12:32 pm

Baron Alcyoneus wrote: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.

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