SpudFiles

Ok I wanted to make a smaller hybrid out of schedule 40 piping. The combustion chamber is roughly 10 by 3 inches long and the barrel is about 26 by 1. My idea was to find a mini fan that I could put inside of the combustion chamber, and turn it on with the cap off and spray right guard or butane into the chamber, before this I would have a ball of ducktape placed at the top of the barrel ( ducktape makes a very very very good seal ) the fan in theory lol would suck all of the fuel and more air into the chamber. Then I would cap it off. And inject some compressed air into the chamber. with like a bicycle tire valve or somekind of vavle using a bicycle tire pump. We would only put in 10 pounds of pressure. The barrel has a bigger hole at the end of it, its a 1.25 to 1.0 peice on the barrel. I would have the 1.25 in the chamber so the gas would hit into a bigger hole then pressurise into the 1.0 in hole. Would this idea work ? would it be powerful for its size ?. Then Id shove the ducktape down after I pressurized and fueled the chamber for a bit more pressure.

I'd suggest doing at least schedule 80. Schedule 40 is just not safe for hybrids no matter the mix in my opinion.

really I would need schedule 80 for such a small chamber ?, well ok but would this little cannon be able to shoot something like a marbe with ducktape around it to make a good seal ? would it be powerful ?

jmeyer1022 wrote:I'd suggest doing at least schedule 80. Schedule 40 is just not safe for hybrids no matter the mix in my opinion.

That would be good advice if the OP actually made any sense.

it make sence.........


Let me explain again.

10 inch long combustion chamber by 3 inches wide............

1.25 to 1 inch barrel reducer (whole barrel lenth is 26 inches)........

Mini Fan in combustion chamber for proper and better atomization of gas particles..........

1 way valve so that you could ram a little bit of compressed air into the chamber. 10psi at the max....


Do I need to brake it down more ?

frankrede wrote:

jmeyer1022 wrote:I'd suggest doing at least schedule 80. Schedule 40 is just not safe for hybrids no matter the mix in my opinion.

That would be good advice if the OP actually made any sense.

I think this is the 2nd time you've made a comment at me for absolutely no reason. I'm just letting him know SCH 40 and HYBRID don't go well together. Relax.

My main qusestion is how fast do you think the projectile would be going. Would it be powerful lol

I was talking about Frank, First off don't double post. And will you be using a check valve( one way valve) for filling?. I'm guessing you will be using a burst disc seeing as its a hybrid. Have you built cannons before? Pneumatic or combustion?

You best bet would to be use quick connect for both the gas (propane or w.e you decide to use) and for the air. I'm no expert on any gun but your plans are to bland to do anything right now. Search around the forums more.
http://members.tripod.com/potatogunwarrior/hybrid.htm
Those are good plan to work off of.

Well I wasnt planning on running alot of psi at all. 10 pounds of pressure would be fun. Im just loooking for a little cannon not a big Mofo. My idea is to use enough air pressure to get like 30% more power or something you know. The limit to the amount of psi I would use is when the projectile begins to come out of the barrel. Ive built like 3 full sized potato cannons and prolly 10 minis. All combustion


I just want to run a little bit of compressed air like 5psi or 10psi nothing huge.

Well if that's case run at 2x (14.7) PSI, Use a union to put your burst disc into. Even though its small I still suggest using SCH 80 just to be safe. PVC explodes, not splits. In my opinion though, go a little bigger too.

OK thank you. I will go 80 with it. But for a small one wold this hybrid shoot further than a combsution that was the same size ?

I'm just barely able to follow your design idea from your description. But...are you actually contemplating building a hybrid, spray and pray style???... Why?

You don't say if the sched 40 is iron, aluminum, pvc or whatever. If you're thinking pvc, you can stop right here....don't do it. Also, a 3" chamber would actually be considered a fairly large one for a hybrid.

A hybrid requires fairly precise fueling. If you were to get an ignition, it would be sheer dumb luck. Why not build a meter system and inject it in the air connection? Your fan idea isn't going to pull in significantly more than 1 atm of pressure, being fuel and/or air.

I assume the duct tape ball you talk about is the projectile?

Have built a standard combustion ro pneumatic cannon before?

Nope nevr in my life built a cannon nope.


Im done here Im just going to go do it because my buddie made one work the same way. But obvioulsy it doesnt exist because its sheer luck how it fires everytime.

Nope never works

Nope never built a cannon

I have head of somebody on this site exploding a pvc (shedule 80) hybrid at 2x. Thats 2 times atmospheric pressure or right around 30 psi. Something to keep in mind.

To answer your question, a hybrid that size will produce pretty damn fast marbles.

Why not go steel and have the ability to go way more powerfull and the added safety?

I don't know much about hybrids but I have to agree with jook and Starman. The last thing you want is PVC exploding its not pretty.