SpudFiles

I've always wanted to mix armature rocketry with spud guns. Using compressed air to shoot a PVC rocket out with a model rocket engine then having the engine igniting a few feet past the barrel to achieve a longer distance.

I have a few ideas on how might to do it but has anyone tried before?

Any Ideas?

Apparently this isn't illegal according to the ATF; we had a discussion about it in the past.

If the moderators don't mind then I would lke to dig up some ideas. However I would like to follow the rules. Perhaps I'll look up the previous thread.

And this was PCGUY's post regarding forum rule

http://www.spudfiles.com/forums/viewtop ... tml#142915

Thank you for the clarification. If it legal lets proceed...

Does any one have Ideas? I figure I'd do it with some sort of timer... wouldn't even know where to start looking though

There was another thread on this not too long ago.
I think the most difficult thing would be to rig the rocket to go off after coming out the barrel, especially the barrel of a pneumatic.

If the rocket where to fit snugly in the barrel, and was big enough store all the needed ignition components, why not have a push button rigged to be depressed inside the cannon. So when the rocket leaves the barrel it opens and completes the circuit which would hopefully ignite the rocket engine.

ShowNoMercy wrote:big enough store all the needed ignition components

All you need really is one of those small 12v camera batteries, just enough get a wire hot.

I was thinking along those lines. Nothing I'm going to try until I finish my current project...

12v camera battery... good idea. I was looking at maybe 2 nine volt batteries

Would a combustion work any better? Would it be enough to ignite the rocket?

Nope, I have tried to light the rockets with a butane lighter before, and it doesn't work. I know I know dumb idea, but I was not myself .

Jared Haehnel wrote:Would a combustion work any better? Would it be enough to ignite the rocket?

if you had to pack the motor with match heads or similar it would probably work, but now we're drifting into solid propellants.

I think, I'll stick with electric ignition.

Any idea how long it would take for the rocket engine to ignite once it had current going through the primer?

I think you guys are forgetting how heavy pvc pipe is and how weak model rocketry motors are.

i'm assuming that you're gonna shoot it out of a cannon, then light the engine to overcome the starting energy needed for liftoff? if there was a delay in the ignition of the rocket engine, then you could probably use a sprinkler valve piloted with a solenoid, and rig the primer and the solenoid in series, then when you launch the cannon, the engine fires a tiny bit afterwards. Now that i think about it, this design could be adapted to make an RPG style launcher, only without the G...

edit: thought it through a little more... bad idea...