Super Soaker Central

hi

i am considering to build this gun for an Olympics for chemistry

There, however, are some restrictions.

some of which are dimensions(must fit in a a Concrete Form Tube of dimensions 8" round and 32" high)

and

i will probably need an inboard water reservior(cannot use commerical products i.e. the backpack to hold the water)

so if anyone could tell me these answers

i would appreciate it

thanks

btw i also looked at the guide for the gun

http://www.sscentral.org/homemade/aph/

That tube should be plenty big enough. I assume to don't have to operate the gun while it's in the tube (pumping would be difficult).

For a reservoir, pipe works fine. This can be onboard, or separate, connected by a hose of some sort.

Though I'm not sure what you mean by "commercial products". Everything's got to be bought. I don't see how using a hydration pack as a reservoir would differ from using a drainpipe. You've still got to make the connection to the gun and stuff.

Also, air-pressure water guns aren't exactly chemistry. They're more physics, particularly fluid dynamics, and engineering.

well the pipes and products in the list are allowed

they mean products by finished products such as a water gun already made

although this is more physics oriented, i do have to explain the fluid dynamics, engineering and such

i would also like more detailed information about the onboard water reservoir.

There isn't really any "more detailed information about the onboard water reservoir." If you make a gun with an onboard, you'll be one of the first. Most people use backpacks for homemades. I think generally people are more concerned about the 'functional' parts. Plus with large pressure chambers, reservoirs need to be also large to be useful, to the point that an onboard reservoir would make the gun too heavy.

Onboard reservoirs are absolutely possible, but it's become hard to find information about them. We dropped our articles about them about a year ago; here's one, although it might not be too helpful. DX also built a bunch of water guns with onboard reservoirs, but many of the images at the old SoakerMedia forums are now broken; but here's one of his designs.

I'm a little confused...is this for a science fair or for the Chemistry Olympiad? From what I know the latter is merely a written exam.

i do not even need much water to be in the gun

i just need to squirt it out a ridiculous length

also this is for a chemistry Olympiad, in which i must compete against other schools to shoot water in a farther distance

Welcome to SSC!

If you want distance, go for Supercannon II: http://www.sscentral.org/homemade/supercannon2.html

The gun is essentially as powerful as a water gun can be and would easily fit your dimensions.

One thing worth mentioning is that I used non-pressure-rated parts in that water gun. I was ignorant to this when building and while it's very unlikely to cause a problem, I'd suggest using 4 inch couplings and 4 inch to 2 (or 1 1/2 if you can find it) inch bushings and a 2 inch to 1 1/2 inch bushing rather than the bell reducer and bushing combination used in the guide. This'll be more expensive but will be pressure rated.

If you still want something like the APH but want an onboard water reservoir, look into polycarbonate water containers. Thanks to the BPA scare, these can go for fairly cheap. A bottle like this should be perfect.

@Silence: Pepper's water gun's still online: http://www.sscentral.org/homemade/pepper.html

My preface should be removed however.

Tangentially related - is this for the 41st International Chemistry Olympiad in Cambridge, England?

nope

its on NJIT for high school

Yes, Ben is right: for distance, you'll need the most flow and highest pressure possible, and with that form factor, a SupercannonII would be perfect. The main barrier would be ordering/buying the required supplies.

the supercannon 2 is way too big and this aph gun seems to be too big as well

i may need to modify to make it smaller, if i do, will the performance of the gun decrease?

It depends on what you do.

If you simply reduce the height of the pressurized tanks, then the performance will be the same. If you reduce the number of tanks, you may see a slight decrease in performance. If you reduce the diameter of the barrel tubing from 3/4" to 1/2", then you will take a large performance hit. There's not much reason to reduce that diameter though.

Shortening the pressure chambers will decrease the shot time more than anything else.

If the Supercannon II is too big you could always make a 2" version.

I would make a supercannonII-esque gun, just modify it to fit the requirements.