SpudFiles

My friend and I built a very simple combustion cannon today and we were having trouble getting the fuel mixture right. We used two screws and a bbq lighter for our spark. We used hairspay as our fuel. Every once in a while we would get a good launch with a nice loud bang, but most of the time we got nothing even when we could see a spark. I suspect the problem was in our fuel mixture. How long should I spray the hairspray for and how long should I let it mix with the air? Also, are there any other more consistant propellants besides pnuematics that are cheap/easy to use with our simple cannon?

Thanks

If you built it today your probably having trouble with the cold air temps. Hairspray condenses, (gets watery) very quicky when it's cold out.

use spray paint lol i found it works great 8)
cold or hot it works for me but propaane is great too but wd 40 or spray paint would be the best.

Is it a mortar type of cannon, if it is, try a Cap full of lighter fuel.

Or if it isnt try putting in your ammo without pushing it all the way down the barrel (leave it at the the beginning of your barrel). Next put in your fuel. Close the endcap and then push your ammo all the way down your barrel.
This way more air is being forced into the chamber.

I'm not quite sure what you mean by mortar type. We just have a simple 3 inch or so chamber and an inch and a half barrel. We didn't even mount the ignitor yet.

Forget it, its not a mortar type its a regular combustion.

When I say mortar I mean that you simply have one big tube (chamber and barrel combined) with on end sealed and the fuel goes in from the top.

in cold weather just try using starting fluid, its my favorite spray in fuel, and besides you built it and shot it the same day? thats a no no for safety