pneumatic mortar

[Eddbot]

i was thinkin about makin a pneumatic mortar for airsoft, and was wondering if anyone knew how a real mortar actually works, and i know someone's gonna say something like this:

is it that hard to type words in google

but i already did, and i couldn't come up with much, so i'm asking here

[MrCrowley]

All I (think I) know is that when the mortar is dropped in the tube it lands on a firing pin which ignites a small explosive charge (like how a gun works) which launches it in the air...and you know the rest.

I did have an idea for a pneumatic one...

You use a non modded sprinkler valve and have two copper contacts (connected to the valve) inside the barrel, and when the projectile is dropped you would have something on it (something conductive) which connects the two contacts, actuating the valve and launching the projectile.

[blind909]

or just make it a burst disk, and put a nail one the bottom of the projectile, drop it down the barrel, and BOOM!

[MrCrowley]

I think I discussed that with someone a while back and we weren't sure if the burst disk would still burst effectively and not just rip open which will have an effect on the flow. It's worth a try though.

Though the nail could help stabilize the projectile in flight which is a bonus.

[Eddbot]

2 questions: is there any way to have enough power to get a relatively large distance without having to pump alot? and if i keep it relatively low pressure would it be safe to use CO2 cartridges without a metal expansion chamber?

[MrCrowley]

1. Buy a compressor, you'll definitely need one in this hobby

How far are you looking at?

2. Yeah, but I wouldn't recommend it with PVC and/or a sprinkler valve.

There is a table somewhere on this site of how much pressure you will have per capsule for a set chamber volume.

[Eddbot]

1. it's gotta be portable and relatively stealthy, compressors are loud

2. if i made the whole chamber out of steel could i connect it directly to the sprinkler, or would the decompression still make it unsafe

[MrCrowley]

It's the cold that effects the sprinkler valve.

You could use on board CO2 and fork out big bucks for a reg.

Why does it have to be stealthy and portable? I hope you're not planning on shooting anyone even if it is at paintball

[Eddbot]

not at people... that's why i want it low power, and i'm gonna use the idea for a detonate on impact shell that i haven't prototyped yet... it's the middle of the night and i'm bored, gimme a break for thinking about random/usefull stuff, and it's airsoft not paintball

[MrCrowley]

I still say don't do it, prototypes, especially homemade prototypes can go wrong, and we really don't need the publicity if it does.

If it's a paint mine, that's alright because it's only paint, but when you're shooting solid objects, it's another story.

[Eddbot]

when i say detonate i mean spread bbs in a circular radius without the use of incendiary devices, and i'm broke anyway so i'll probly never get started

[Carlman]

well about a week ago i came up with a design for marbles or aa batteries here is the linky for the combustion one : http://www.spudfiles.com/forums/marble- ... 12251.html

and here is a diagram for a triggerd burst disk pneumatic one:



since this is air soft you want to screw in an unwanted solinoid from a modded sprinkler valve to drop the pressure in between disks.

[DYI]

CO2 regs don't cost big bucks from what I've seen.
I've seen decent CO2 regs for under $100.

Burst disk pneumatic mortars are about as simple as pneumatics get. With a 2" porting burst disk, you could get impressive results even with relatively low pressures of 100 psi or so.

[Carlman]

this may help eddbot aswell, what is something that will burst at 80psi arounds in a 15mm bore?

[DYI]

No idea. Smallest burst disk valve I've ever used was 30mm, largest is the 45mm on the SCTBDC.