SpudFiles

After all the help i got from everyone on my design, http://www.spudfiles.com/forums/nerf-pa ... t8876.html I decided to go ahead and build the gun. I just finished gluing it, so i have not tested it yet, built i will post results tommorow hopefully. The blowgun valve is mounted on the removable handle to function as a trigger. Despite it's strange appearance, this gun is quite comfortable to hold, with one hand on the trigger and one supporting the air chamber. This gun has multiple shots, the concept of which is discussed in the above link. Questions? Comments?

Thats pretty good. I'm looking to build a pnuematic, an this is an inspiration. I wana see those test pics! How much was the whole thing? How much was the green valve?

umm.... whats the point of the bottom most ball valve? also i think moving the trigger up to shorten the hose on it would increase performance. it probably wont increase all to much though with small projectiles like paint balls and Nerf darts

ps - im betting the "green valve" (sprinkler valve) cost $10-12 and the blowgun that is being used to trigger it was probably $7

thats pretty good. if i were you i would have made most of the cannon metal, then hooked an air compressor regulator to it, then the ball valve, and then the air chambers. you would get more consistent shots.

overall, that owns. now go show people what a REAL nerf gun is...........

Hailfire:
Thanks for the fast reply! Im not sure of the total price, but i would estimate around $25. The green valve is an Orbit Watermaster sprinkler valve, and i got a great deal on ebay for $9, but they usually cost around $15 not counting shipping.

Singularity:
The bottom most valve does not have much of a purpose, but i put it there to prevent losing air when detaching the air source.

VH_man:
Thanks for the compliments, but this gun is really just to test the concept of multiple shots without a regulator, and i am not very experienced with metal and regulators and things.

so i take it that there is more to come?

i like this idea. alot. i might have to use it for a bb sniper of somesort.......

somewhere on a NERF forum someone posted the formula to determine how many times a high pressure tank could fill a low pressure tank, given the pressure of the large tank, the size of the large tank, the size of the small tank and the desired pressure of the small tank.

have you ever tried making stefans? they work 10000000X better than normal darts, and they leave welts........

I have never tried stefans, but i do have the equation i think you are talking about. It was provided by boilingleadbath in my design thread:

PSInew = (PSIold + 15) * (Volmain-chamber / (Volmain-chamber + Volsecond-chamber)) - 15

I will try plugging some numbers into this, and i was also considering installing pressure gauges on both chambers. However, i dont know how to install them after drilling the hole. Will they actually seal screwing into a curved piece of pipe? I could use some help on this subject.

basically, drill a hole the diameter of the bottom of the threads of the guages. push the guage in and twist untill its about 3/4 of the way in. remove the guage, wrap it in teflon tape, and screw it in all the way.

i do this for all my cannons and it hasnt failed me once.

btw, go through where the PVC pipe is double thick, ak the endcaps on the end of your chambers.

Ok, today i did some nerf testing. It was very windy outside, so i could not get correct distances, but indoors i achieved 10 acceptable shots at 35 psi, which i think is pretty good. It is really amazing to be able to reload so quickly and easily. This gun operates at much lower pressures than i expected, and at 50 psi it literally shreds the darts to pieces. The gap in performance is most noticable between the first and second shots, and after that it slowly drops in distance and speed.

btw, thanks for the info, vh_man.

nice looking cannon youve got there! I like the compact(ish) look of it, so well done.
Its quite hard to tell in the photos, so how long/big is it actually??