Chain Flinger

Summary

An early participant in Blue Origin recently sent me this link, which depicts a category of device that when I was there (1999-2006) we referred to as an Aitkenator or, more colloquially, a chain-flinger. This inspired me to dig up some old notes on the topic. I’m going to write them up in a series of posts here and put them up sporadically in coming weeks. For the most part this won’t be about anything that happened at Blue Origin. It’s about a series of scientific papers, the most recent of which was published in 1950.This all started out as a study of the physics of bullwhips. These are remarkable in that, though they are of prehistoric origin, and extremely simple, they are capable of breaking the sound barrier (as has been well documented at least as far back as 1927, the bang that you hear when someone cracks a whip is actually a sonic boom). On further investigation it became clear that the same physics are at work in the case of chain-flingers such as the one shown in the above linked video. The only difference is that in the case of a whip, one end of the system is free.During the time I was working on this at Blue Origin I had trouble settling on a name for this field of investigation. I ended up calling it filamentary systems: the physics of long slender flexible things that are moving. I was never really happy with that name. Recently, upon cracking open some of the old papers I found while studying this, I came across the German phrase Kinetik der Kontinua: the physics of continuous media. I like that a lot better and so I’m going to call it by that name, or KdK for short.Everything that I did was based on these historical papers, which I plan to cover one by one in this series. I don’t claim to have done any original work in this field. I simply went to the library (yes, it was that long ago) and found these papers and translated them.In this first post, before digging into the actual science, I’m going to address a question that might have already sug...