Odin

I have heard about the "Kn factor" for calculating the internal diameter of nozzles for both core and end burning rockets. Does anyone know how it works?

I first became interested in pyrotechnics some forty odd years ago. At that time there was very little information available on how to make BP, although the constituent parts were readily available in many chemist shops – yes even charcoal which I think was used to relieve flatulence! I am afraid that my attempts at BP were pathetic; the powder would fizz and bubble and that was about it. I then foolishly moved on to sodium chlorate and sugar and although I did have some successful rockets, my main interest in pyrotechnics, there were two occasions where the rockets blew up and frightened the life out of me. That was enough for the next thirty four years.

Then, along came my son, who at about age sixteen expressed to me an interest in pyrotechnics after talking with his Uncle who whilst at Uppingham School attended two lectures by the Rev. R Lancaster. Well I thought let's have another go. As a frequent visitor to France I was able to procure my KNO₃ and sulphur reasonably easily, but again lots of fizzle but no pop. Then after surfing the net, we came up with the answers i.e. very accurate scales and a ball mill – bingo it worked. After that I was hooked, and shortly afterwards we made our six tonne pneumatic press (inspired by Dan Williams).

As I mentioned earlier, I prefer to manufacture rockets although mortars/mines are good fun. In addition to the scales, ball mill and hydraulic press I have acquired other tools including some excellent rocket tooling (core burners) from Greg Boyd in 0.5" and 0.75", and some 0.5" convolute paper tubes from Inoxia and 0.75" tubes from Pyrotubes4Europe. I believe that at the date of this post Pyrotubes4Europe are no longer trading.

I am still trying to perfect my rockets and mines, the problem being to make a reliable payload for stars and flying fish and of course a big bang to go with it. In addition I have made my own designed re-usable rocket; my main problem being a simple but reliable recovery system. So, to continue my hobby and learn more I have applied for membership of the UKPS – wish me luck. Odin.