RPG (not dungeons and dragons you nerd)

[psycix]

I think you wont need a heat shield, its basically a combustion gun with water in the barrel. You dont need a heatshield for that too, unless you are going to stand in front of it.
Dont expect this construction to be powerfull. Combustion doesnt grant very much pressure and secondly, it lasts a short time.

[magnum9987]

ok, their is no water. and secondly did you understand the scale I am building here? I said I'm building the combustion chamber to 5in diameter. I'm planning on using a huge volume of gasses and I do think the back blast could be harmful, just like standing too close to the barrel of a gun going off gives you powder burns.

[psycix]

5 in? thats not "that" big
Ofcourse you should keep distance but doing so with common sense is enough.


No water? that means even less thrust!
Expect it to jump up a few feet, and then come down again...

[magnum9987]

How is it going to combust with water down the gas shaft?
Plus I've seen kids playing with weak nerf launcers that use the same concept as mine and achieve distances up to 30 feet, plus the projectile weighed nearly 12 ounces, while the bottle I plan on launching is significantly lighter, and the pressure in mine is sure to be greater.

[Ultimate Weapon]

To be blunt and honest, magnum your idea (and you) are retarded and it will NOT work. Someone had to say it cause it's true.

[daxspudder]

to be 100% honest, this is a really dumb post. i would rather read the "how tall are you" crap than this... if your gonna stand near the front of your gun magnum you deserve to get burned, and from the apparent degree of your intelligence you should skip the part where you build the gun and just soak yourself in gas and light a cigarette[/flame]

saying "hows it gonna combust with water down the gas shaft"(wtf is a "gas shaft") is like saying how does a gun shoot with lead in the barrel... its all about how smart you are, the collective you that is.

EDIT: i just reread your original post. okay all you doing is building a tiny spud gun with a cork in the barrel as ammo, then your putting a empty tank on the end that you incorrectly call a chamber, i think your idea will only shoot 20-30 feet at best, and there is no way in hell you could possibly get flash back from it, not unless your using o2 which would be entirely stupid in and of itself

[psycix]

How is it going to combust with water down the gas shaft?
Plus I've seen kids playing with weak nerf launcers that use the same concept as mine and achieve distances up to 30 feet, plus the projectile weighed nearly 12 ounces, while the bottle I plan on launching is significantly lighter, and the pressure in mine is sure to be greater.

Well, very simple, you inject fuel, let it mix, and spark the ignitor.
It combusts.

Ever blank fired a normal combustion gun and felt the "recoil"?
This is the amount of force your rocket will get, and it will not be enough.

Try it out yourself. Grab a random combustion, put a rag in the barrel, fuel, mix, point barrel down and dont hold it. Set it against a tree or something.
It wont fly.
If your lucky it will jump a few inch from the ground and then fall over.

PVC is too heavy for this all, and if you are using lighter stuff, its not safe (you planning to use DWV bad boy?)
The size doesnt matter.

A "rocket" twice as large may have twice the propulsion force, but it also weighs twice the amount, so it wont come very far.

This idea of you may have seemed nice to you, but it will not work as planned. Accept that.

[magnum9987]

First of all, That was uncalled for/.
Second I mean that the water would just go down the barrel and flow into the chamber (Which i will continue to call it god damn it!). So the presence of water is redundant.
THe chamber has a greater volume than the half liter water bottle, much more. The gases inside the chamber will go to the bottle. Water rockets take air pressure and because of the property of water (It doesn't expand) the air pressure pushes water out with a delay.

But i do realize with out water this could not work. So i'll turn it from an RPG to a mortar of sort. THe bottle would point upwards. A pipe comes out at a 90 degree angle then turns up for about 10 inches. Turns 90 degrees again and again and the chamber is 10in tall and 5 inches in diameter.
Because it goes vertical, it allows for water to be kept in the gun and allows for a necessary power increase.

[magnum9987]

Update of idea
Screw the mortar part. Instead i'll make it into a sort of rpg again. This time, the bottle itself is the chamber. A cork of some sort with a bbq ignitor plugs the neck. Their is a shaft that will put some distance between the shooter and the round, as well as a heat shield.

Another Idea
HUGE chamber: 8in diameter, 20in long. The bottle is attached directly to the bottle. An additional pipe stems out from a certain point that goes around the bottle, which will keep gases in a safe area.