That thing is pretty cool! I like how compact it is, but you don't need a capacitor and transformer, all you need is 3 nine volt batteries.

I was to noobish to look into building a piston valve untill now. I think I'll start after mt curent project!

Thanks for the info.

It sounds good but I would recommend buying at a local Lows or something if you can. If you cant find it locally then buy it.

I've built a canon similar to that. Yours looks pretty sick and well put together! You should put a support at the end of the barrel and air tank for stability.

I personally don't like any thing else for rockets than on board propulsion, preferably combustion.

I've bought flechette before and IT'S FREAKING INSANE! With a good canon it can go through a 10" thick tree! Generally pretty easy to make with plastic fins. It must have 3 or more fins or it will tumble so just flattening the end will not work well at all.