Search found 784 matches

by clide
Sat Dec 27, 2008 2:51 am
Forum: Hybrid Cannons
Topic: BACH – Bolt Action Cartridge Hybrid
Replies: 52
Views: 24455

That is really slick, looking forward to seeing it work.
by clide
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...
by clide
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...
by clide
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...
by clide
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...
by clide
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...
by clide
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...
by clide
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...
by clide
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...
by clide
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...
by clide
Sun Nov 09, 2008 5:05 pm
Forum: Combustion Cannons
Topic: semi-auto combustion #3
Replies: 11
Views: 2498

Based on that instructional video and some transparent models on their site it looks like that propane hammer has nearly the same mechanism as the C3. The only difference is it uses the inertia of that ring to perform the pumping action rather than manually doing it.
by clide
Sun Oct 26, 2008 2:08 pm
Forum: Combustion Cannons
Topic: How to Build a Propane Meter
Replies: 56
Views: 24893

Here is the video
[youtube][/youtube]
by clide
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...
by clide
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...
by clide
Fri Oct 10, 2008 10:29 pm
Forum: Off-Topic Hobbies
Topic: Initial Lathe Operation
Replies: 16
Views: 2914

Is it doing anything at all, making any sound? Have you checked the fuse? Oh and I hate to ask, but is it plugged in?