an Air soft rocket launcher

[MisterTwisted]

I have a good Idea of how to put this thing together. I can piece it all together with abs pipe. Then for the propellant I am looking at using a plumbing tool called a "gallo" gun. It uses a specialized C02 canister made for the device. It claims to put out 800 psi. Does any one know a math formula to figure out how fast the nerf rocket would be traveling at.

[quigly]

I hope you aren't planing on putting all 800PSI into the launcher. If you are, I don't want to be anywhere near it.

But besides that, I don't think there is any formula as it depends all on pressure, barrel fit, length, and so on. I would say trial and error may be your friend.

[Switchback]

I decided to track potato guns for you...maybe you could do a little inferring on this:

The highest projectile speed recorded from a spud gun is 933.3 m/s (3,062 ft/s) (approximately 2.7 times the speed of sound) with a 16.6-gram (256 gr) 20 mm plastic slug from a hybrid using a 1 MPa (150 psi) pre-ignition mixture of air and propane.[18] The highest velocity attained by a potato specifically is approximately 2,700 ft/s (820 m/s).

16.6 grams, 150 PSI, 3,062 FPS. If you're good, this might help... I'll see what my Algebra II experience can give me here...

NOTE: Different propellant used, but the Gallo Gun gets more PSI. I don't think an 800 PSI tank is a good idea either.

[Sir Stubby Eyre]

Interesting concept. With the rocket launcher that I made I got the best performance at 45-55 psi, anything over that was wasted. If the "gallo gun" can do multiple shots from one canister it might work.

My main concern is that with this system you do not have any holding tank beyond the Gallo Gun. Most pipe will not withstand 800 PSI, it will explode.

Don't bother with ABS, use PVC, it has a higher PSI rating. Stay away from foam core ABS, there is very little PSI rating on them.

Test your system several times using lots of safety devices, Sand bags if need be, before you hold it next to your body.

Good luck with your project.

[Falcon7]

Not sure, but I think there are different ratings of ABS which can withstand different pressure levels. The grade I used in my mortar can withstand 200 psi, which is way more than you should be using. You should have some kind of regulator to lower the psi, a safety release valve to make it impossible to overfill the launcher, and a gauge on the launcher to measure out the psi you want. Check out http://www.spudtech.com, they have a lot of useful parts for sale.

[MisterTwisted]

all very helpful. I should have been a little more specific. The galo gun is the pressure chamber and trigger mechanism all in one... they are around 40 to 50 bucks a pop so I have yet to get one. Not to mention I do not want to just jump in feet first and blow My hand off with all 800 psi. every thing here is very helpful. Thank you all.

[Eyes On]

This is probably more helpful than AP: http://www.spudguns.org/