36 replies to this topic

[Foam Shooter]

This is one of my two projects I am working on.


It is a SnapBow made from 2" PVC.


The ranges are definitely better then the SnapBow. My sock is on differently then usual. I have a PVC 1/2 to 3/4" bushing with the 1/2" part cut off so it is just the 3/4" male adapter. I filled this with epoxy putty and then screwed it into the gun with 1 " screws. I then put 3/4" female busing on this with the elbow leading to the rest of the stock.

Questions/Comments/Concerns?

[rork]

That's...beautiful. *single tear rolls down cheek* It's also one of my back-burner projects, temporarily abandoned due to plunger head issues and a magnificent distraction. Ah, well; it's good to see it executed so nicely. Getting on here and seeing you coming up with new stuff every 2 days is...well...it's just like Christmas.

PS: slap an RSCB clip on there.

[Foam Shooter]

That's...beautiful. *single tear rolls down cheek* It's also one of my back-burner projects, temporarily abandoned due to plunger head issues and a magnificent distraction. Ah, well; it's good to see it executed so nicely. Getting on here and seeing you coming up with new stuff every 2 days is...well...it's just like Christmas.

PS: slap an RSCB clip on there.

I actually got a smile on my face reading that post. Thanks a lot. I guess you can call me Santa Clause, just kidding.(unless you really want to). I haven't really looked into RSCB clips until a few days ago so I'll study up on those. I'll try it if I like what I see.

[Carbon]

Very nice! What fittings did you use for the front?

And yes, you need to get an RSCB/inline on there. Quiet Asian Man posted a few Big SNAP variants that used it, and got great results. Huge air volume + big spring = awesome. A few variations using 2" PVC is also one of my backburner projects, as well.

[rork]

My problem was that the huge rubber washer simultaneously folded and created a LOT of friction. I'm going to try a system using large O-rings. I calculated that one of these things should be pushing almost 25 ci of air, which is downright mad.

[nerfboi]

Wow. That's huge! Looks great. Is this what you were taling about? Just to start it, what kind of ranges are you getting? I'm guessing near the 100's? Looking nice. Too bad I don't have any dough to make this.

[rork]

The normal SNAPbow (1 1/4" plunger tube) gets well over 100' with the right dart/barrel combo. I shiver to think what you could do with this monstrosity, which pushes almost twice as much air.

[CaptainSlug]

Oh what disturbing levels of overkill we have wrought...

[Radio]

Oh what disturbing levels of overkill we have wrought...

Do stefans have a terminal velocity?

...or does that only apply to falling objects.

[rork]

NO springer is going to be able to push a stefan much over 150', and that's pushing it hard. The rule of thumb is that springers top out at around 100', airguns at around 200'. Of course, there are exceptions that prove the rule (Plusbows, Pump shotties, etc.), but foam darts are singularly ill-suited to being fired very long distances; they're just not aerodynamic enough, and they shed energy fast. ~Rork

And CS: my interest in this design is that you could add an inefficient but dreadfully practical RSCB system and STILL have enough air to (theoretically) stay over the century mark.

Edited by rork, 11 November 2008 - 02:00 AM.

[perezinthenet]

What did you use for the plunger head? Are you using a plusbow spring?

[Foam Shooter]

Carbon: I used a 1 1/2" to 1" bushing. I then put a 1" to 1/2" bushing on this. I had to wrap the 1 1/2" bushing in e-tape.

nerfboi: This is not what I was talking about. I have a better one coming. I think it goes without saying that the ranges are efficient but I will measure some today if I get some time. It will easily get over the 100'.

perezinthenet: I used a rounded 1 1/4" cap for the catch part and then I wrapped a 1" coupler in some e-tape and hammered it into the cap. I then did a normal SnapBow washer assembly except a 2" rubber washer and then a 2 1/4" washer.

[nerfboi]

Man, don't even bother. I'm pretty sure it ill get over 100'. How much did this cost to make? Adnd how long is the PC? I might make this from the extra(if any) after I make CS's External Tank. But that's if I get money anytime soon.

[Carbon]

I shiver to think what you could do with this monstrosity, which pushes almost twice as much air.

Keep in mind that air volume is only part of the equation. Plunger mass plays a part as well, and while the air volume is huge, the plunger head is also quite massive, reducing possible gains. My initial comparative tests only showed a gain in range of about 10'-20' (going from ~80' to ~95') when using the same spring, going from 1.25" to 2".*

*Of course, another issue with this much plunger volume is that the necessary barrel length starts to get goofy long (assuming the 1:4 ratio). My usual barrel choice is brass, so I was never able to test above a 12"...which is the length that I use on a standard SNAP. Better ranges may be possible, but barrel material makes it more difficult to achieve.

Anyway, it's like you were saying, rork...I think the main advantage in using 2" PVC is in using some manner of inline/RSCB system, because of air volume. Slow air seems to be okay in a system like that.

[Meaker VI]

I'd be interested to see specifically your setup you used on this. The plunger head and spring especially, did you find some kind of massive ACE spring? I was planning to build something slightly similar to this, but I was going to use bungees because I didn't think I could find a spring.

[Quilan Fett]

NO springer is going to be able to push a stefan much over 150', and that's pushing it hard. The rule of thumb is that springers top out at around 100', airguns at around 200'. Of course, there are exceptions that prove the rule (Plusbows, Pump shotties, etc.), but foam darts are singularly ill-suited to being fired very long distances; they're just not aerodynamic enough, and they shed energy fast. ~Rork

It is not that they are so unaerodynamic, but that little physics law that says that if you drop a rock and throw another rock flat, they will both hit the ground at the same time. On earth, you have to take into account air resistance, and a small amount of rise from Bernoulli's principle, but for the most part, the dart only has as long as it takes for it to fall to the ground to travel it's whole rage. Because of aerodynamics, air resistance, and inertia, it is very hard to get the dart going fast enough to get it to travel more than 150 feet before gravity has its way.

[Foam Shooter]

nerfboi: It costs < $20. The PC is the same about 13" including the bushing in it.

Meaker: I used a +Bow spring.

[Draconis]

I still need to make one of these for balls! It's been on my back burner for a while now too.

[nerfboi]

Maybe you should try to make this one fire balls. Defiantly has the size.

[MercenaryXero]

And I thought I was all done with my homemades for the year...

Heh. I'm definitely considering making one.

[Carbon]

Maybe you should try to make this one fire balls. Defiantly has the size.

It definitely does. I'd be really interested to see what a +bow spring could do in a ballgun.

[Foam Shooter]

I'll try making it fire ball.

Carbon: Do you think that you could explain how you made yours shoot balls.

[Carbon]

I'll try making it fire ball.

Carbon: Do you think that you could explain how you made yours shoot balls.

A summary is worthwhile, because the process was spread out over a few pages. Here’s a few of the points that I found:

Ballguns typically use a retaining ring to keep the ball in the barrel until enough pressure builds up. I used a 1.25” sanitary coupling as the retaining ring, because it had a nice ridge in the middle. I shaved/sanded it down until the ball could pop through with air pressure (that’s all trial an error). And since airflow needs to be high, I just shoved the retaining ring into the end of the pressure chamber, with a few turns of tape to keep it tight.

The interesting discovery was that dead space is helpful in a ballgun, because it gives extra volume for pressure to build before forcing out the ball. Large volumes of low pressure air seems to be key. So, that's where the inline clip came in...it fired better with it than without it.

Edited by Carbon, 11 November 2008 - 04:54 PM.

[Carbon]

I could use some data on the balls themselves. What are you using, and where can I get some which I can expect to be the same?

Foam practice golf balls from Kmart. Six for $4, or 50 for $20....not sure about the size.

[Draconis]

I could use some data on the balls themselves. What are you using, and where can I get some which I can expect to be the same?

Foam practice golf balls from Kmart. Six for $4, or 50 for $20....not sure about the size.

Honestly, I would stick with K-Mart, too. Though the majority of what I have now are practice golf balls from Target. Available 12 for $5 or so. The drawback is that they are noticeably smaller than Nerf balls, and have the dimples. At first, the dimple sound like built in awesomeness, but alas, they allow air leakage around the sealing rings. They are also so much smaller that they don't really work with Reactors, and get substantially shorter ranges with my motorized Ballzooka. The K-Mart balls are between the Target balls and Nerf balls in size.