SpudFiles

So im new to the site but ive been tinkering with potato guns for a little over 5 years. I have been designing ideas for an onboard compressor for a new pneumatic gun. As i took apart the compressor i noticed that it makes a huge spark as it runs. so ive been thinking what if i make a double chambered gun. one for combustion and one pneumatic. what if i put the actual compressor unit in a combustion chamber (which will also have metered propane), but then have the air feed from the compressor motor to the pneumatic chamber and have a sch 40 y connecting from my sprinkler valve attached to the pneumatic chamber and also connecting the combustion chamber to one barrel, with two ball valves just before the y. thoughts?

You should consider building a hybrid piston cannon, it will work perfectly well as an exhaust valve pneumatic but at the same time with fuel and ignition thrown in you can fire it either as a simple combustion or with a pressurised fuel air mizture.

so ive never built a hybrid before, how do i go about doing that? what else would i need? and how is the explosion timed with the valve? isnt that tricky to do? pictures would really help

Take a look at the Hybrid section or the wiki. The links can be found at the top right of the home page.

Generally, hybrid cannons use burst disks, so the combustion triggers the firing.

d.marty wrote:so ive never built a hybrid before, how do i go about doing that? what else would i need? and how is the explosion timed with the valve? isnt that tricky to do? pictures would really help

The overpressure cause by the combustion forces the valve open, have a look at my mini piston hybrid.



As suggested, some reading on combustions would help.

I don't know if the spark of your compressor would work as an ignition source, many people run fans inside their combustion chambers to promote a homogenous mix and the motors never seem to cause ignition...

JSR: Those diagrams you posted, so do they not need burst disks? Because Ive been wanting to build a small hybrid for ages but the thought of reloading a burst disk for each shot put me off.

Alster370 wrote:JSR: Those diagrams you posted, so do they not need burst disks?

No, that's how a piston hybrid works.

Burst discs have the advantages of maximum flow resulting in best power, and they are very easy to use and the design is super reliable overall. Of course, pistons are fantastic for convenience and still plenty powerful depending on design. I myself am still in love with my burst disc cannon. I built that thing like 2-3 years ago or something and everything is still rock solid just like the day i build it. And thats because the design is dead simple.