Simple button valve

[Glickman]

Here for exposure, posted something like this a while ago in tinker's, didnt get any responses... :(

anyway, im sure you guys have seen the rocket launchers with the big valves you need to turn, wasting alot of air, so i was thinking of ways for a simple button valve alternative, for using something to get a few shots out of, such as a 4 ounce tank

heres waht i thought of http://img160.echo.cx/img160/2679/rocket4rr.jpg

as you see the red would be pushed, aligning with the black, alowing the air to be flow, but then shut closed (i forgot to add the spring underneath the red :rolleyes: silly me.


any ideas would be greatly appreciated

[Alpha]

Forgot the spring to return it!

I like! Maybe add a chamber before it so you can make it even more efficient! Like you open the valve for a second, then close it. The chanmber is now filled. Hit the dump switch, and the gas exits the chamber, goes through teh switch valve, adn pushes teh rocket/grenade/stuff out.

[Duzzy]

It sounds like a good idea, but I think it would need to be electronically activated to work.

If you hold down the button longer you get more air correct?

This would allow low shots, hot shots, and probably would be very hard to get consistency with. It would also be hard to regulate at the normal 250 fps rule that I believe most LAW type devices are under because the velocity would change based on how long you held down the button.

This is a thought, but if you have air flowing through at high PSI and high speeds, will the button "pop" back up at all? I mean, if you had a spring sure, but how strong would the spring have to be to close it properly? And then how hard would it be to push down?

BTW, I think Tank drivers would hate this idea...

Nice thought, but I don't know if it would work.

[VFX_Fenix]

The push button could be connected via link arm to a cam or trigger which could be spring loaded and facilitate a strong enough return to close the valve while still being easy to opperate.

[TheTramp]

All you have to do is make sure the dump chamber (and you will want a dump chamber) to barrel ratio correct and you'll fire the rocket at 250fps using one 12gram per shot.

The problem with a push button valve is that you'll have a good amount of pressure (~80psi)pushing against whatever you are using to seal it. That's not going to be easy to actuate so directly.

[Maggot6]

Sounds like something I could do to one of my potato cannons...

[TheTramp]

In the end you'll be better off with a sprinkler valve that has the pneumatic modification.

[Glickman]

new idea!

im going for simplicity, as thats usually the most durable
http://img251.echo.cx/img251/1406/idea19my.gif

its a 2 way valve, when the air goes through the top vent, it closes the red valve, but through the side, it opens it spilling the air, alowing for a decent volume of air to readily excape.

this way you could technically have a "dwell"

open to ideas, suggestions and flaming for my poor excuse of a mspaint-chop!

[TheTramp]

Here is the simple way:

http://www.geocities.com/tbrown111083/sprinklervalvesoupup.htm

Barrel on one side and a sealed dunp chamber on the other. You can even regulate the pressure and shut off the fill line for the shot so there is no need for a dwell.

[Glickman]

Here is the simple way:

http://www.geocities.com/tbrown111083/sprinklervalvesoupup.htm

Barrel on one side and a sealed dunp chamber on the other. You can even regulate the pressure and shut off the fill line for the shot so there is no need for a dwell.

hmm, wait, so itll reach a certain pressure, use something to dump, then recharge, and await another dump?

[TheTramp]

Sure, just use a slidecheck. Open it and the dump will fill to the regulated pressure, close the slide, fire, repeat.

[ojhspyro89]

If you have the right machiens you can make a piston valve. They are by far the most powerfull pneumatic controlled valve yet, with the exeption of a burst disk. But anyway, they are VERY VERY powerfull at low pressures. at about 30 psi, i was grenading potatoes before they got outa the barrel. Its also a very successfull design. If ya want, i could make one for like 60 bucks or so depending on size. I love them i live by them.

[TheTramp]

But anyway, they are VERY VERY powerfull at low pressures. at about 30 psi, i was grenading potatoes before they got outa the barrel.

That's not going to help you fire nerf rockets at 250fps. ;) 1000fps perhaps..... :eek:

[ojhspyro89]

That's not going to help you fire nerf rockets at 250fps. ;) 1000fps perhaps..... :eek:

Yeah i was kinda going towards the point of that you can shoot at very low pressure or High pressure low volume and still be rather fast. Its all bout effeciancy i guess.

Did u know its impossible to shoot 1200 fps (mach 1) with normal air?

[TheTramp]

Yeah i was kinda going towards the point of that you can shoot at very low pressure or High pressure low volume and still be rather fast. Its all bout effeciancy i guess.

Did u know its impossible to shoot 1200 fps (mach 1) with normal air?

No I didn't know that. Compresion/expantion issues I assume?

[Glickman]

Yeah i was kinda going towards the point of that you can shoot at very low pressure or High pressure low volume and still be rather fast. Its all bout effeciancy i guess.

Did u know its impossible to shoot 1200 fps (mach 1) with normal air?

i disagree :p
http://img96.echo.cx/img96/8243/untitled5as.jpg


god help anyone who doesnt know what that is (i swear, even at 9 and 13, my sisters had no idea...)

[trains are bad]

HAHAHA

if you make the barrel of you LAW short enough, it comes to a point in the curve where dwell doesn't matter. Even infinite dwell will still not shoot hot. Do this by testing carefully and cutting a bit at a time. This works if you have a single load you will be using like a nerf rocket. This is not very air efficient but is a very simple/cheap/light/handy way to build one with a simple valve. It's just a matter of holding the valve until it clears the barrel and trying to let go soon enough to keep some air.

[ojhspyro89]

HAHAHA

if you make the barrel of you LAW short enough, it comes to a point in the curve where dwell doesn't matter. Even infinite dwell will still not shoot hot. Do this by testing carefully and cutting a bit at a time. This works if you have a single load you will be using like a nerf rocket. This is not very air efficient but is a very simple/cheap/light/handy way to build one with a simple valve. It's just a matter of holding the valve until it clears the barrel and trying to let go soon enough to keep some air.


A problem with that is air effeciancy. After the projectile leaves the barrel the access air in the tank/chamber will be dumping into atomospheric pressure pretty fast which would just be a loss of air. The best way to do it is get a 2 to 1 ratio of chamber to barrel. That is the way to get maximum performance out of a pneumatic cannon. You also might want to go download GGDT. Its a program to simulate and help design pneumatic air cannons. Its a very helpfull program but you need to know alot of random things like dwell of the valve you use. Its a very nice program

Oh and the Mach 1 thing with normal air is the air isnt fast enough it cant expand fast enough to push out the projectile that fast. Now if you heat it up or use a lighter gas like helium you can acheive speeds of mach 1 and above. Its been done before with compressed air and propane mix. dont try it ull get hurt lol.

[Glickman]

A problem with that is air effeciancy. After the projectile leaves the barrel the access air in the tank/chamber will be dumping into atomospheric pressure pretty fast which would just be a loss of air. The best way to do it is get a 2 to 1 ratio of chamber to barrel. That is the way to get maximum performance out of a pneumatic cannon. You also might want to go download GGDT. Its a program to simulate and help design pneumatic air cannons. Its a very helpfull program but you need to know alot of random things like dwell of the valve you use. Its a very nice program

anything is better then a 1-shot depletion of a 12 gram :D , ill look into that though

[JoshK]

Could you do that...but have it go into a chamber that has a little gauge on it? Once the gauge goes to a certain pressure you let go of the button, and either open a lever or push another button?

Also....I don't know much, but how would you make sure there is a tight seal inbetween the part with the whole, and the red part?

[JoshK]

i disagree :p
http://img96.echo.cx/img96/8243/untitled5as.jpg


god help anyone who doesnt know what that is (i swear, even at 9 and 13, my sisters had no idea...)

That be bad stuff...

bad stuff + big boom bomb = tons of :tard:s in our future generations...

[doc_Zox]

my internal piston design:
http://premium1.uploadit.org/docZox///boomstick.jpg

PVC liability issues caused me to go with an aluminum MKX:
http://premium1.uploadit.org/docZox//MKX.jpg

[Glickman]

Could you do that...but have it go into a chamber that has a little gauge on it? Once the gauge goes to a certain pressure you let go of the button, and either open a lever or push another button?

Also....I don't know much, but how would you make sure there is a tight seal inbetween the part with the whole, and the red part?

i was thinking of that too, and for the second part, o-rings :D i could show you waht i had in mind, but thats more crappy drawing i would have to do



thanks for the blueprints :D im gonna see if i can simplify that ;)

im trying to make a simple single tube design, easy to carry on my side

[TheTramp]

doc zoc's launchers are wonderful but far beyond most people's ability (or pocketbook ;) ).

Here's something that the average guy could make. Obviously it's not painted in this picture and I hadn't cleaned up the hose and wires yet.

http://www.jayloo.com/files/pics/1000/cannon12360.jpg