9 replies to this topic

[iknowmy3tables]

I already posted this on spudfiles here, and I was hoping to finish a auto-loading system before I posted this but I'm not sure if that will be happening anytime soon, so here it is
I'm trying to get a video of it shooting but my phone's media card is corrupted
anyways here's what it looks like

as you can see it has a marker barrel and the chamber has been extended with a 1/8" nipple and some 1/2"cpvc, and receives air pressure from an external source
performance: I'm using a small air tank and this thing gets plenty of shots between fills, it's extremely effective providing great performance with only a small amount of air consumption. I'm using stock darts and hitting just shy of the 50' mark at only 20psi.

I'm with Doom on QEV valves, they are perfect for nerf. the most beneficial factor for a valve used in a pneumatic nerf gun is opening speed, and there's a reason why they don't call QEVs slow exhaust valves. however I have to admit a decent qev and 3way control valve can be expensive, so you might want to try this as a cheaper alternative it might not be as good but it cost ~$5 to make

here's a diagram on how it works, but if you don't know how the secret strike works then you'd better check this out first
this is what it looks like in the closed/filling position

and this is when it's open/firing


so here are some pictures of the construction, I'll try to add more pictures of parts and better instructions later

this first picture is from nerf haven internal directory Courtesy of Gengar003

if you cut enough off and maybe heat the plastic a little it should clip on just fine

Edited by iknowmy3tables, 14 April 2010 - 03:24 PM.

[k9turrent]

So the pump is now the trigger? Cool Beans

[moosa]

Too bad your pump stroke isn't linked to a rotating turret mechanism (hint, hint)...

[iknowmy3tables]

yeah I've thought about that, but I've had difficulty seeing how I'd put id mount it while minimizing dead space and flow restriction

by the way I've added a handle from a longshot front gun


also I have uploaded an older video of the valve working if you want to see

the clicking sound is from the valve firing a pulse of air

[moosa]

Very cool that you have a real trigger on there now. I've never seen or heard of anything quite like this I don't think.

Of course, your current setup isn't ideal for range as it is. 50 feet is not generally considered "outstanding," and the fact that you've expanded the air tank is, I would think, somewhat negated by the length of the barrel. I just figured someone was bound to point these things out anyways, but of course that's sort of looking past the point of this mod.

Edited by moosa, 10 April 2010 - 07:40 PM.

[iknowmy3tables]

yeah now that you mention it I probably shouldn't have used the word outstanding for my range of 50ft, compared to the single shot blasters for nerf wars it's not a lot, but I play HvZ and my campus rules forbids Stefans and anything that shoot further than 50ft at a flat angle

you can easily give it outstanding range with modifications, for example this morning just for fun I tapped some 1/8" threads into a 20oz soda bottle obviously it's over-sized and screwed it onto the nipple and tested it in the hall at a flat angle; the first was 35psi the second upper 20s, the first appeared to reach short of 60' but then the second I realized that the unstable streamline darts were bouncing off the walls and light fixtures so it was much further, so the setup I have is pretty weak, but the valve itself setup should have plenty of potential

[TantumBull]

That's extremely awesome. You are fighting the pressure with the trigger pull, but that's kind of outdistanced by the fact that this all costs about 5 bucks. EXCELLENT work!

[imaseoulman]

I really don't think your tank expansion is doing anything for your range. 1/8" is too restricting and your barrel is short. You can get the same ranges, perhaps slightly better just w/ rebarreling it and maybe a plug the pump. It's interesting though.

[iknowmy3tables]

I'll have to disagree with you on that, first off 1/8" npt threads are larger than 1/8" even my 1/8" nipple's ID is greater than 1/8", second your probably confusing air flow at lower pressure differences (like those in spring plungers) to airflow at higher pressure differences, as pressure difference increases the flow increases exponentially so you can't accurately make comparisons to lower pressure differences that you'll encounter more often

besides I have also tested this with an over sized chamber extension attached to the same 1/8" fitting and there was a massive increases in performance, so if a bigger chamber extension attached at the same 1/8" NPT fitting resulted in more range therefore there is more than enough flow though the 1/8" NPT fitting to significantly increase range and performance

Edited by iknowmy3tables, 13 April 2010 - 09:29 PM.

[billyblue888]

I overlooked this topic before but now that I see it I have to say good job.