Search found 784 matches
- Sat Dec 27, 2008 2:51 am
- Forum: Hybrid Cannons
- Topic: BACH – Bolt Action Cartridge Hybrid
- Replies: 52
- Views: 24455
- Sat Dec 27, 2008 2:36 am
- Forum: Pneumatic Cannons
- Topic: STV ver. 2 clear inline piston valve
- Replies: 25
- Views: 11824
I see we disagree on how piston bounce exists... Leaving me to wonder..... Whos right? to the testing board! Like you said it is a complex process with lots of variables involved. In addition to the increasing pressure from the rapidly moving piston you also have to consider the rapidly falling cha...
- Fri Dec 26, 2008 9:23 pm
- Forum: Pneumatic Cannons
- Topic: STV ver. 2 clear inline piston valve
- Replies: 25
- Views: 11824
did this used to be a filter becus i have a fitting similar made out of brass and it is very heavy Yep, that is exactly what it is, although they are usually called strainers. It's one of those things that I had never noticed before, but once I learned about them I started seeing them everywhere. a...
- Fri Dec 26, 2008 4:20 pm
- Forum: Pneumatic Cannons
- Topic: STV ver. 2 clear inline piston valve
- Replies: 25
- Views: 11824
STV ver. 2 clear inline piston valve
Some of you who have been around a while may remember my Straight Through Valve that I <a href="http://www.spudfiles.com/spudtech_archive/viewtopic.php?f=17&t=13120">posted on Spudtech</a>. It was an attempt to make a piston valve with a strait flow path to hopefully improve efficiency, but while it...
- Thu Dec 25, 2008 3:44 pm
- Forum: Pneumatic Cannons
- Topic: Pneumatic gun efficiency
- Replies: 16
- Views: 3285
Also, I'm not sure a valve that closes when the dart leaves is worthwhile. My modeling so far indicates that unless you make an oversized chamber at low pressure you're not going to save much or any air. Something to keep in mind. It depends what you are looking for, if you have higher pressures av...
- Thu Dec 25, 2008 3:25 pm
- Forum: Pneumatic Cannons
- Topic: Christmas cannon
- Replies: 3
- Views: 1037
Christmas cannon
Not mine, but I saw this featured in the Instructables weekly newsletter. It's instructions for a small cannon made by fungus amungus. He uses BCArms as his supplier for some of the parts. http://www.instructables.com/id/Christmas_Cannon/ The video cracks me up, although it's probably not a great id...
- Thu Dec 25, 2008 3:04 pm
- Forum: Pneumatic Cannons
- Topic: Pneumatic gun efficiency
- Replies: 16
- Views: 3285
I'm fixing muzzle velocity and figuring out acceptable pressures and volumes after that, so the efficiencies I'm looking at should be directly comparable. Because the goal is to reduce total air consumption, I first must choose an acceptable level of performance before looking at efficiencies. Perh...
- Thu Dec 25, 2008 12:25 am
- Forum: Pneumatic Cannons
- Topic: Pneumatic gun efficiency
- Replies: 16
- Views: 3285
If you're determined enough, you would be surprised what you could make without a lathe. I made several guns that required o-rings before getting my lathe, but if you do have access to one it would certainly make things a lot easier. As far as I know the GB Semi is the only gun using a HEAR valve at...
- Wed Dec 24, 2008 6:15 pm
- Forum: Pneumatic Cannons
- Topic: Pneumatic gun efficiency
- Replies: 16
- Views: 3285
So you are optimizing for the smallest potential energies in the chamber to obtain a specific performance with a certain sized barrel? One way you can boost efficiency (assuming you will be shooting multiple times) would be to not use all of the air in your chamber, because after your projectile lea...
- Wed Dec 24, 2008 1:09 am
- Forum: Pneumatic Cannons
- Topic: Computer modeling
- Replies: 11
- Views: 3022
Have you been able to determine if the problems come from low chamber volume, high pressure, a combination of the two, or either of the two? It is not immediately clear from reading through you post, but I may have missed something. I assume this part of the code: if Pc < Pb: Pc = Pb came from the t...
- Sun Nov 09, 2008 5:05 pm
- Forum: Combustion Cannons
- Topic: semi-auto combustion #3
- Replies: 11
- Views: 2498
- Sun Oct 26, 2008 2:08 pm
- Forum: Combustion Cannons
- Topic: How to Build a Propane Meter
- Replies: 56
- Views: 24893
- Sat Oct 18, 2008 2:06 pm
- Forum: Pneumatic Cannons
- Topic: Semi Auto Nerf Gun
- Replies: 78
- Views: 26852
I suggest something like 4622K53... That is what he is using in the video :wink: But you do bring up a good point, what is wrong with using the slide valve? You can put a spring on it so you don't have to move it in both directions. The stroke may be a little long compared to a push button valve, b...
- Sat Oct 18, 2008 1:25 pm
- Forum: Pneumatic Cannons
- Topic: Semi Auto Nerf Gun
- Replies: 78
- Views: 26852
3-way valves aren't really that hard to get a hold of. McMaster has all kinds of them (pages 958-965). You could mod a blowgun to work as a 3-way; the flow isn't great but it is enough to trigger a QEV. Or use Ebay, a quick search turned up this one, I'm sure you could find cheaper alternatives by l...
- Fri Oct 10, 2008 10:29 pm
- Forum: Off-Topic Hobbies
- Topic: Initial Lathe Operation
- Replies: 16
- Views: 2914