Question about Mythbusters\' Polybolos

[Koyuncu]

I recently saw the Mythbusters' episode called "Arrow Machine Gun" testing famous design of Dionysius of Alexandria, a 3rd century BC Greek engineer at the Rhodes. However there is some design difference between Mythbusters' and historical recordings. My point is not about historical accuracy of test.(I could not decide where to post this, sorry if it is wrong section.) I am curios about how MythBusters' machine works.

Here the difference. In historical records, Philo of Byzantium mentions about this machine and recorded that in order to load machine, the chain drive needs to be moved back and fort. Like the video below.

http://www.downvids.net/the-repeating-03...07998.html

However, the so called Arrow Machine Gun is rotated backwards only. There is no back and fort movement but a continuous circular motion. My suspect is they are using a sort of crank mechanism hidden in the base of machine. Do you have any idea about this?

http://www.youtube.com/watch?v=nDbmAJKwN...page#t=19s

Thanks.

[Eleatic Guest]

You mean on 0:34-38? No idea!

The Museum für Antike Schiffahrt in Mainz, Germany, has a complete reconstruction as well as a demonstration model of the spanning mechanism which is non-continuous (back and forth) as described by Philon. And as the proud Bürger of the mother city of the printing press, they cannot possibly err, can they? :wink:

[Koyuncu]

It seems Mythbusters changed the design altogether, yet for a artillery fans all innovations are worth for investigation.