73 replies to this topic

[CaptainSlug]

I have no idea. But I suspect 22 darts is likely to be the ceiling of being reasonable in terms of mag dimensions and spring load.

[Eightdotno]

I have no idea. But I suspect 22 darts is likely to be the ceiling of being reasonable in terms of mag dimensions and spring load.

What about a homemade drum magazine?
Is that a possibility?

[CaptainSlug]

Possible, yet challenging and/or annoying.

[KaneTheMediocre]

What about a homemade drum magazine?
Is that a possibility?

 

I was just working on that recently.  I didn't get to the point of a fully assembled drum, but from the spiral frame I found that in addition to friction stacking as the number of darts increasing and the base friction force per dart being larger owing to the curve, the darts start to dramatically bind up more once you get close to a full turn of the spiral.  This may be why the Nerf raider drum is only one layer deep.  I always thought it was a waste to do a drum mag with only one layer to the spiral, but it may be that is all that is really possible with nerf darts.  I'm not 100% sure that the phenomenon is related to the total angle rather than the total linearized length of the magazine, but it sure seemed like some voodoo started once I got close to 360 degrees.  So, it might NOT be possible (at least, for multiple layers) without a system of intermediate pushers/followers, which is tricky for a variety of reasons.

Sure I could just do a 1-layer drum, but it wouldn't really be a more compact magazine for the capacity than a straight mag would be. 

[snakerbot]

 

I was just working on that recently.  I didn't get to the point of a fully assembled drum, but from the spiral frame I found that in addition to friction stacking as the number of darts increasing and the base friction force per dart being larger owing to the curve, the darts start to dramatically bind up more once you get close to a full turn of the spiral.  This may be why the Nerf raider drum is only one layer deep.  I always thought it was a waste to do a drum mag with only one layer to the spiral, but it may be that is all that is really possible with nerf darts.  I'm not 100% sure that the phenomenon is related to the total angle rather than the total linearized length of the magazine, but it sure seemed like some voodoo started once I got close to 360 degrees.  So, it might NOT be possible (at least, for multiple layers) without a system of intermediate pushers/followers, which is tricky for a variety of reasons.

Sure I could just do a 1-layer drum, but it wouldn't really be a more compact magazine for the capacity than a straight mag would be. 

 

Yeah, I was worried about that for my spiral drum design as well. I couldn't come up with a solution I was really happy with, which is one of the several reasons I haven't pursued that design. I do have one idea I'd like to test if I can convince myself it'll have a chance of working.

[Meaker VI]

Oddly enough, Slug & I have been having a PM conversation about this very subject.

 

 

I was just working on that recently.  I didn't get to the point of a fully assembled drum, but from the spiral frame I found that in addition to friction stacking as the number of darts increasing and the base friction force per dart being larger owing to the curve, the darts start to dramatically bind up more once you get close to a full turn of the spiral.  This may be why the Nerf raider drum is only one layer deep. 

 

Yeah, I was worried about that for my spiral drum design as well. I couldn't come up with a solution I was really happy with, which is one of the several reasons I haven't pursued that design. I do have one idea I'd like to test if I can convince myself it'll have a chance of working.

 

Did either of you look at doing a carousel instead of a single pusher? Like this:

 

 

Seems like you could put more spring force into something like that without messing up the darts, since they're only actually being pressed a few darts deep by something solid.

[snakerbot]

Oddly enough, Slug & I have been having a PM conversation about this very subject.

 

 

Did either of you look at doing a carousel instead of a single pusher? Like this:

 

<snip>

 

Seems like you could put more spring force into something like that without messing up the darts, since they're only actually being pressed a few darts deep by something solid.

 

I hadn't considered that, no. That looks essentially like a three layer deep version of the sprocket that hasbro uses. I'm not sure that's going to solve our problem though. The issue as I see it is that the darts are dragging against the outer wall of the track they run in, so the friction force increases dramatically with higher numbers of darts, leading to the binding. More spring force also increases the friction force, so I think the same thing would happen with the carousel. My design focuses on removing that friction by essentially having the "walls" of the spiral track move with the darts. I think conceptually it'll work, it's more of a "how do I build this thing?" sort of issue. It requires winding a strip of fabric into a constant force spring, so if I can find time this weekend I'll see if that's even possible.

[KaneTheMediocre]

Oddly enough, Slug & I have been having a PM conversation about this very subject.

 

 

Did either of you look at doing a carousel instead of a single pusher? Like this:

 

 

Seems like you could put more spring force into something like that without messing up the darts, since they're only actually being pressed a few darts deep by something solid.

 

I'd thought about it, but I didn't realize firearms drums needed/used them.  I thought they just had it easier due to bullets being relatively incompressible.   This is helpful and simpler than what I was imagining, which involved folding followers.

[Meaker VI]

...

...

I think we're getting off-topic in this excellent thread about a specific build, so let's take this spiral-mag discussion to PM's.

Edited by Meaker VI, 29 April 2017 - 01:46 PM.

[Ice Nine]

I think we're getting off-topic in this excellent thread about a specific build, so let's take this spiral-mag discussion to PM's.

 

Since I think only admins have access to group PMs, you might be better served starting a thread for it (since this would fall under the "acceptable ideas thread" umbrella). I could splice off these posts to do that, if you want.

[CaptainSlug]

Topic split

[Meaker VI]

 
Since I think only admins have access to group PMs, you might be better served starting a thread for it (since this would fall under the "acceptable ideas thread" umbrella). I could splice off these posts to do that, if you want.

Well shoot, I appear to be able to do that. But if we want this a topic that's cool too.

My question to these guys in the PM was: how did you wind your spirals? Slug suggested scrollsawing one out from a template, then inserting thin material into the cut. That seems excessively difficult though.

Also, Snakerbot- your adding moving fabric sounds like a belt system, which would be better served as-is and not spiraled up. And frankly, a belt would also be fine as a high-cap solution IMO. Maybe I'm misinterpreting what your plan is though.

I'd also messaged slug about doing something like a high-cap airsoft mag but with darts (my rough tests indicated that it'd be complicated if it's possible), a hopper-fed self-reloading belt/clip system, and a giant coiled RSCB type setup.

[snakerbot]

Meaker noted in PM that my description made it sound like a 'spiral conveyer', which is almost exactly correct. There will be a spiraling feed path for the darts, with walls on either side (like a box magazine that has been curled up) with CF spring/fabric conveyers on the inside and outside wall of each path. The springs will spool up where the drum transitions from straight to spiral, and there will be a flexible, roughly 6 dart long follower to extend into the straight section, much like Hasbro's drums.

 

I did manage to test winding fabric into a CF spring, and it does work, at least with the 4lbf spring I had. I suspect the reason the spring went off to the side at the end is that I didn't have any control in place to keep it still. I'll have to think of a way to do so without interfering with the fabric.

 

Maybe fabric isn't the right material. Something teflon film like 8569K16 might work better, but I figure fabric would be easier to work with, as it won't crinkle like a film would.

 

Edited by snakerbot, 29 April 2017 - 07:59 PM.

[CaptainSlug]

Maybe use load strap, nylon strips, canvas strips, or even ribbons that have finished edges. If you find a fabric you want to use it just needs to be run through a serger which will prevent the edges from fraying.

My mom always had and still has a very equipped sewing room. The last thing I asked her to sew that was Nerf-related was a bulk dart pouch.

I had discussed briefly with Meaker about just straight-up using tape measures to pull a follower, but after thinking about it the tape in the tape measure itself doesn't transition all that well over curves. But if you unwind one then un-rivet and replace its measuring tape with fabric strap it would wind up however much of the fabric will fit inside until it binds.

[Meaker VI]

The springs will spool up where the drum transitions from straight to spiral...
 
I did manage to test winding fabric into a CF spring, and it does work, at least with the 4lbf spring I had...

Ah, makes way more sense now. I'd second slug's reccommendation of webbing or ribbon. Ribbon would be plenty strong and has the benefits of being thin and often very slippery. I was thinking you'd have the spring in the middle of the mag like in my example picture and not off to the side.

[NerfGeek416]

I've been playing around with a different way to achieve this using a motor. I wanted a spiral channel for darts and a follower that slides along the channel. The follower can slide radially on an arm that is driven by a stepper motor at the center. The idea is that this way the motor can provide a constant force on the darts, and when paired with an IR sensor at the feed point, could drive the system at any RoF without putting unnecessary pressure on the darts.

 

It'd be a pretty complex build, but it's probably something I'll attempt eventually. I'd like at least 60+ capacity for it to be worth it, but we'll see how realistic any of that is.

[Eightdotno]

What about that 50 round drum that Hasbro wanted to release with the stampede but never came out with? I think that we could base a 60+ round drum off that.
Also that patent on it might help with building a drum mag.

Edited by Eightdotno, 02 May 2017 - 11:35 AM.

[snakerbot]

What about that 50 round drum that Hasbro wanted to release with the stampede but never came out with? I think that we could base a 60+ round drum off that.
Also that patent on it might help with building a drum mag.

The problem is that the 50-drum doesn't seem to have actually worked, and if Hasbro, with all their money and engineers getting paid to work on that stuff (I'm an engineer, but I'm paid to do other things) couldn't do it, then I don't feel confident in my abilities to make that work either. Also, there isn't a patent for the 50-drum. The best we get is some incidental pictures in the stampede patent. I'm not telling you that you shouldn't try it, because I'd love to see someone get that, but I will direct my efforts elsewhere.

 

I've been playing around with a different way to achieve this using a motor. I wanted a spiral channel for darts and a follower that slides along the channel. The follower can slide radially on an arm that is driven by a stepper motor at the center. The idea is that this way the motor can provide a constant force on the darts, and when paired with an IR sensor at the feed point, could drive the system at any RoF without putting unnecessary pressure on the darts.

 

It'd be a pretty complex build, but it's probably something I'll attempt eventually. I'd like at least 60+ capacity for it to be worth it, but we'll see how realistic any of that is.

I like that idea, but you have the same problem the rest of us do with high friction due to high numbers of darts and many contact points between said darts and the walls of your drum. 

 

In other news, I did a little more testing on random bits. I found that new G4 koosh darts can easily take 1lbf without deforming significantly, so that's good news for high spring loads, but it only takes about 0.5lbf to shove darts out through the feed lips on a standard hasbro magazine. The spring in an 18-stick puts out about 0.4lbf at full compression. This is unfortunate for me, because there aren't any good CF springs on mcmaster that put out sufficiently low load and also have enough length to get a decent capacity.

 

This leaves me with two options as I see it.

1. Abandon the idea of CF springs from MCM and start looking elsewhere, E.G. tape measures

2. Redesign the feed lips on top of the magazine so they hold darts in better. If you're willing to give up on breech guns and flywheels only is acceptable, then you could have a full loop around the darts for the first inch or so, at the expense of loading ease. I'm not a big fan of the full-loop method personally, since I like being able to top-load scavenged darts, but this is something I might have to consider.

[Meaker VI]

As much as having the setup compatible with mag-fed blasters is desirable, I'm leaning more and more towards a belt fed or tube fed (think powered coiled up RSCB/hopper) system. There it's less a question if it's possible to build and more of a "how convenient/reliable is this to carry".

[NerfGeek416]

Dart choice can help a lot with feeding. Koosh are well known to be very grippy. Slugs are extremely easy to move around, and I can imagine a giant drum system on a Caliburn, for example. Mengun are somewhere between the 2, and are slippery enough to feed in hoppers, so I think they could be made to work. I think the darts would need more support than I originally envisioned. I'm gonna keep brainstorming on this idea.

[snakerbot]

Meaker/NerfGeek416, it appears that we've just set different goals for ourselves. My standard superstock loadout is a Rapidstrike with Koosh darts, so two of my design requirements are that it works with the Rapidstrike, and that it feeds Koosh darts. Hopefully with three different people working on three different concepts, at least one of them will work!

[Meaker VI]

Meaker/NerfGeek416, it appears that we've just set different goals for ourselves. My standard superstock loadout is a Rapidstrike with Koosh darts, so two of my design requirements are that it works with the Rapidstrike, and that it feeds Koosh darts. Hopefully with three different people working on three different concepts, at least one of them will work!

Well, my design goal is a tad more complex than what I posted. I think it lays out like this:
 

GOAL: Design a high-capacity dart feeding system that:

1. Uses standard 0.50" dia x ~3" Foam Darts
2. Holds, at minimum, 100 darts
3. Is very easy and very fast to reload - easier/faster than a standard mag at minimum
4. Is re-loadable on the fly
5. Is reliable
6. Is inexpensive to build, or failing that, is inexpensive per capacity - the standard is the cost of the same capacity in Nerf clips
7. Is easily replicated

Compatibility with existing systems is a bonus, but not a requirement. I've got some nice mag-fed blasters, but if I need to I can keep using mags with them. I've also got a bunch of boomco stuff that this won't help at all - that stuff spurred my desire to figure this out actually. Reloading (20) 20-round clips takes too long between rounds, so I want something I can just dump handfuls of darts into and be ready to go.

[NerfGeek416]

If you remove that first requirement, there are plenty of high cap Nemesis based systems available....

 

Your requirements scream "dart hopper" to me. I'm envisioning something akin to the nemesis mech, but oriented differently, and with some kind of agitator to encourage the darts to feed down tip first. And then some sort of ejector which gets rid of backwards feeding darts. It can dump them on the ground for all I care, if the rest works, you could have as much capacity as you want. Who cares if you lose 10% of it?

[Meaker VI]

If you remove that first requirement, there are plenty of high cap Nemesis based systems available....

The Nemisis is the impetus for this, so I'm not surprised
 
Ed: and I don't want to switch to HIRs unless I absolutely have too: darts are so much cheaper and widely used. They're also usable at higher velocity.

Your requirements scream "dart hopper" to me. I'm envisioning something akin to the nemesis mech, but oriented differently, and with some kind of agitator to encourage the darts to feed down tip first. And then some sort of ejector which gets rid of backwards feeding darts. It can dump them on the ground for all I care, if the rest works, you could have as much capacity as you want. Who cares if you lose 10% of it?

Yep, most of my ideas look like dart hoppers too. Currently playing with a 2-liter as the hopper, it seems that darts dropped in stay facing down, but if there are backwards darts my plan was to just fire them. As you said, who cares if one in 10 is a squib when I've got hundreds?

Edited by Meaker VI, 03 May 2017 - 10:49 AM.

[KaneTheMediocre]

Dart choice can help a lot with feeding. Koosh are well known to be very grippy. Slugs are extremely easy to move around, and I can imagine a giant drum system on a Caliburn, for example. Mengun are somewhere between the 2, and are slippery enough to feed in hoppers, so I think they could be made to work. I think the darts would need more support than I originally envisioned. I'm gonna keep brainstorming on this idea.

Mengun darts are not slippery enough to feed in standard hoppers.  Wyes need to be modified to feed them reliably without a varmint hunting blaster, and even with a varmint hunting blaster I'm not sure.  It's been a while since I used a koosh dart, but I recall cut down kooshes being slightly more hopper friendly than men-gun darts as well, although that may have more to do with shape than texture.

To further complicate matters, I have men-guns with at least a couple different types of rubber/elastomer in the tip, so it could be that some varieties of men-gun darts feed better than others.