SpudFiles

good god, that thing is serious!!!!! Call the president ans see if you can sell some of them bad boys

jhalek90 wrote:Tech, I believe you are correct, but the way it is now should work ok. The air has plenty of room to flow into the nipple, I think most of the performance loss would be due to turbulence.

The flow will be very good. The turbulence will limit some of the power when the flow is near sonic.

A quick comment on the valve size to the barrel size, I have found when launching tennis balls that the valve and chamber size makes a huge difference. The difference between launching something with my large chamber large valve is an entirely new league than launching with the same barrel on the marshmallow cannon with the small chamber and 1 inch valve.

As a mid size cannon, it will still be impressive at higher pressure. High pressure will increase the density and thus the volume of air that can get through the nozzle of the valve for more power. With the metal construction, it should really perform above 150 PSI. Over 80 will be impressive enough for starters.

I plan on running it up to 300-400 psi with my HPA paint ball tank.

It remains to be seen however, how many shot I get out of one 3200psi paint ball tank.. (largest "regulation" size avalible)

@tech
The 1/2" porting valve in the video had impressive power, with a 6 foot 1/2" barrel, at 150psi. I can't wait to try the new valve at 150.

On a side not, the new valve is actually just larger than 1.75" porting. Larger than I thought. >:)

mmmmm, this build is going really well.
What type of pilot valve are you planning to use?

A qev piloted by a ball valve.

jhalek90 wrote:A qev piloted by a ball valve.

use the valve that was in the vid to pilot that monster and a qev to pilot it and the ball valve to pilot it

Every piston valve I've ever built has fully discharged in a fraction of the time it seemed to take in the videos... is that simply a characteristic of large valves?

saefroch wrote:Every piston valve I've ever built has fully discharged in a fraction of the time it seemed to take in the videos... is that simply a characteristic of large valves?

I believe that has to do with the fact that he's emptying the entire tank through the 3/4" fitting at the top. The small size limits flow which is why it takes so long, and that is why he's having a 2" pipe welded into the tank.

That won't be the case after he gets the nipple welded on 8)
Instead of...
BBBBooooooooooshhhhhhhhhhhhhhhhhh
It will just be...
BOOOOOM!

A sample of the short discharge time can be seen in an on-line video. 3 gallon tank with a 2 inch valve. Note the total lack of any hiss after the t shirt is gone. This launcher is my design. The Arlington HS built it for a competition which they won. I'm in the video at the very end holding the prototype that I made. It has the black 3 inch ABS barrel.
http://www.youtube.com/watch?v=9Klxqav_6NM

To be fair, that's only 35 psi, when I'm comparing it to 100psi, and it's not a dryfire without a barrel.

The time it took to discharge is due to the 1000 cubic inch chamber, and a valve with a 1/2" port.

The new valve has a 1.75" port and the tank is currently in the process of having a 2" nipple welded on as tech suggested.

saefroch wrote:To be fair, that's only 35 psi, when I'm comparing it to 100psi, and it's not a dryfire without a barrel.

I have other shots recorded on my youtube channel at up to 100 PSI.