Morter

[Night Hawk]

Ok guys, well as you can see my first project is under discussion, but im already thinking about my second. I plan to make a morter, that is basically a cannon that fires as soon as the round hits the base of the cannon.

What do you guys think? Would this work? My main concern is the blowgun valve not triggering the pilot.

Here is a sketch, animation to soon follow.

[Hubb]

It's gonna take some heavy ammo to achieve this. Then, you have to consider that the button will only be pressed for a very short amount of time, causing the valve to close fairly quickly, which takes away from the power. Not only that, but you have to find a way to seal your "trigger" as air will leak through there, also deteriorating the power.

Good to see some thoughts, though.

[Night Hawk]

But the airgun only needs to be opend for a second to release the pressure from the qev? I suppose another route is solenoid valves...

[LCTChamp]

I don't think this idea will work very well. You could just make a cannon which uses burst disks. All you would have to do is put something sharp on the bottom of the projectile which would pierce the disk.

[Hubb]

You will get the same results with a sprinkler valve.

Once the button is released, this will cause the pilot area to refill, which will reset the valve. This sounds like a good thing, but if not all the air from the chamber gets to the round, not all the power is getting to it. And, from my experiences (yes, I have tried a very similar method) you will barely get any power at all.

Edit:

I don't think this idea will work very well. You could just make a cannon which uses burst disks. All you would have to do is put something sharp on the bottom of the projectile which would pierce the disk.

Like this...

[Night Hawk]

Ahhh i see, so it would not be long before the piston in the qev is equlised again. Shame. I am reluctant to use burst disks to be honest.

[LCTChamp]

Why would you be reluctant to use burst disks? They work great.

Hubb: I knew I had seen it somewhere, I just couldn't find it.

Edit: Spelling

[Night Hawk]

Ahh i posted before i saw your link. I did search morter on the forums but drew a blank. The burst disks look ok actually. I think i just liked the idea of it all being totally mechanical.

[daberno123]

A QEV plus a slide check valve would be pretty easy way to do it. Golf balls would be ideal for this.

[Night Hawk]

There will still be leakage on the right side of the leaver, unless i place that in a encasing

[inonickname]

Why not use a conductive ammo (or even put aluminum foil on the bottom), then have two leads that are completed by the ammo. This could actuate a sprinkler valve solenoid.

[psycix]

Actually its good to close your pilot valve quickly. This will conserve air as the chamber wont blow out as soon as the projectile leaves the barrel.
Its just like using a hammer valve on a QEV.
It will drain SOME power, but for 20% power loss you can get like 60% air conserving.

[Carlman]

heres a couple of my mortor threads mate, and i also made and did not post a marble mortor with 2 contacts in barrel and a non modded sprinkler valve. Worked a charm, just had the cmpressor on trickle into it (enough to fill chamber in 5 secs), and dropped a round in.

here
and
here

[Technician1002]

Ok guys, well as you can see my first project is under discussion, but im already thinking about my second. I plan to make a morter, that is basically a cannon that fires as soon as the round hits the base of the cannon.

What do you guys think? Would this work? My main concern is the blowgun valve not triggering the pilot.

Here is a sketch, animation to soon follow.

I was wondering if the quick dump valve would be made just for this application. If a heavy object with a poor barrel seal is dropped in the barrel, it should be able to knock open the valve. The only downside is as the pressure is raised, there is more pressure on the o rings making the pull harder. I have triggered the large cannon by filling the barrel with water and carrying it. The weight on the valve set it off.

I just uploaded a video on using o rings on piston valves. Maybe this easy to move valve style which I don't dare load (except marshmallows) while under pressure would work. The demo of the force needed to open the valve is at about 4:30.

[youtube][/youtube]
The video is a little lengthy, but look at the section where I shake open a valve. Sorry if I hijacked the thread for the quick dump valve and o ring discussion. Look for my other thread on the quick dump valve if you need more info.
http://www.spudfiles.com/forums/quick-d ... 17858.html

For a true fat wall launcher, this could be built as a coaxial with the air chamber completely concealing the barrel and valve.

[Moonbogg]

It could be done with a sensor inside the tube that triggers the valve when something crosses its beam. The wire could go through the barrel at the bottom and be sealed with epoxy. It wouldn't have to move in and out like the original design sketch shows. Just my thoughts. This thing would be cool.
To make the ammo slide down the barrel, you could make wooden sleeves or sabots that fit nicely and will slide consistently since a spud may get jammed. Perhaps even foam or something that won't fly far and can be retrieved.