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Mark-13 w/60 Dart Mag (Prototype)

WIP High-Capacity Mag Flywheel Coil-Mag

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#1 Meaker VI

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Posted 22 June 2017 - 04:06 PM

As some of you may have been aware, I've been working on a solution for a high-capacity magazine. I'm posting this to show that I have succeeded, and where my toils have led. I'm dubbing it the Mark-13 (prototype), since it's the 12th 13th blaster I've built or worked on/mostly built (After the Mk-8, it was a JSPB-style blaster, a PSCR, a 3d-printed Durendal, and Caliburn).
 
Without further delay, here's the janky prototype of possible doom:
 
IMG_4337.jpg
 
This is my development. For those who haven't been following along, it's a 3s lipo powered 12v blower hooked up to some Carlon 3/4" ENT Flexible Conduit (alt link for a shorter section); connected to the PVC via Sch 40 3/4" PVC, a threaded/slip coupler, and a threaded ENT adapter at both ends, hooked up to a firing tube that flows freely into a flywheel cage (mine is from a Rayven). As-shown, it has a +/- 20' long coil used as a mag and I've successfully fired several shots off it, and fed a total of 61 full-length darts through it. 65 darts in +/- 30 seconds of continuous firing.
 
The distinction is because I found my connection from the end of the conduit to the FWC to be clogging up with darts. If I were able to spend more time building something right now, I could eliminate that issue. I'll get to it if you don't do it first, but I've been touting this thing for a while now and wanted to get a working prototype out there for others to build off of. No distinction, I've fixed it and it works fine.So far, I have fed it USC's, waffle heads, and stock darts and all fed fine. I suspect I could use the blower I've sourced with a larger coil-mag, but cut my tubing down yesterday thinking it was the issue. These ENT connectors do not like coming off once attached, so I might need to pick up some more prior to continuing coil-mag length testing.
 
This is absolutely a bench rig. It is meant for testing, and I'll need to make a shell for if/when I actually plan to use it in a war. Or I'll cram all that into an old Longshot, I'm pretty sure it'll fit. Or maybe I'll just tape it all together into some franken-monster. For the electrical guys, yes, I know I'm not supposed to use wire nuts that way but once I'd rigged up the FWC I realized it'd be a perfect fit inside 1/2" Sch 40 PVC so I just cut it and wire-nutted it back together.
 
IMG_4338.jpg
 
This is the bench rig with the coil mag removed to show what is going on a little bit better. On the left, the aformentioned blower. This one appears very capable of clearing the 20' coil-mag I'm using. Leading from that is a section of 3/4" PVC that I've cut slots into such that it nests over the locking nubs on the blower (probably could achieve the same result by filing/sanding down the nubs, but I wanted to keep the blower mostly intact). The 3/4" has a hole cut into it for feeding darts through - in the future I'd like this to be a Y or a loading door, but this works ok for now and I didn't have either of those handy. Then there are the connectors and coil-mag, and a section of 1/2" PVC leading to a 1/2" PVC T (because I didn't have a coupler handy) leading to the FWC. That part was clogging at the coil-mag -> PVC connection, so I may need to create a fitting or nest some pipe and chamfer it or just feed through the 3/4 or something.
 

Update: I've figured out a different connector setup: From the coil outlet, ENT adapter, Threaded-socket 3/4" coupler, 3/4" pipe chamfered on the end toward the coil, FWC. My setup uses another coupler and a 1/2" T because my pipe was too short and I wanted a window to see what was going on.

Wiring Diagram.png
 
Here's the wiring diagram. Negative blower and FWC go to the negative battery, positive blower goes through the trigger switch and to the battery; positive FWC goes through a rocker switch, then to the trigger switch, and then to the battery.
 
As for draw, this thing probably needs a much larger battery than I have available. The battery voltage has gone from 12.7 to 11.7 in several minutes of testing and loading. With careful attention, I could probably run this as-is in a war, but only for one 30-minute round and at this time I'd want to be checking it even during that.
 
For the astute among you, you'll have noticed an important omission - this has no trigger. It could, it'd probably be akin to a Zeus trigger or (for full-auto) a simple SNAP trigger. Currently, pull the trigger-switch and everything turns on and that's it. Flip the rocker switch and the flywheels don't turn so you can load more easily. It probably should have a real trigger at some point, since darts resting on the wheels seem to cause the the stock motors this is currently running to jam. Ideally, it'll have a trigger that mechanically forces the last several darts into the wheels so some lag in blower-pressure doesn't cause a firing lag. That's down the line though, I need to get my printer working again before I can really start to figure that stuff out.
 
Comments, questions, and criticisms accepted.


Edited by Meaker VI, 10 July 2017 - 08:28 PM.

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#2 jwasko

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Posted 23 June 2017 - 09:25 PM

I believe you mixed up No and NC in your wiring diagram.

There are some PVC fittings that have decent chamfers pre-made that you want to try. a 3/4" to 1/2" CPVC tee is an example, (it's my favorite for RSCBs). Not sure if a straight adaptor is similar.

 

And don't forget you could use copper instead of CPVC. Same OD, larger ID than CPVC.

 

So

Flex > 3/4" PVC  > 3/4" PVC to 3/4" CPVC adaptor > 3/4" CPVC stub > 3/4" CPVC to 1/2" CPVC Tee/adaptor > 1/2" copper > Flywheels

 

FYI PVC/CPVC adaptor: https://www.lowes.co...ittings/3341714


Edited by jwasko, 23 June 2017 - 09:28 PM.

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#3 CaptainSlug

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Posted 23 June 2017 - 09:30 PM

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So once your printer is fixed you can 3d-print a new 2-by-4 for this.


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#4 Meaker VI

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Posted 23 June 2017 - 10:40 PM

I believe you mixed up No and NC in your wiring diagram.


Shoot, yeah - I'll need to fix that.

There are some PVC fittings that have decent chamfers pre-made that you want to try. a 3/4" to 1/2" CPVC tee is an example, (it's my favorite for RSCBs). Not sure if a straight adaptor is similar.
 
And don't forget you could use copper instead of CPVC. Same OD, larger ID than CPVC.
 
So
Flex > 3/4" PVC  > 3/4" PVC to 3/4" CPVC adaptor > 3/4" CPVC stub > 3/4" CPVC to 1/2" CPVC Tee/adaptor > 1/2" copper > Flywheels
 
FYI PVC/CPVC adaptor: https://www.lowes.co...ittings/3341714

 
I'll need to look into that. Hopefully it's not one of those parts that falls victim to local production differences.
 

So once your printer is fixed you can 3d-print a new 2-by-4 for this.


No no, I'm using a 1x4. So when I print it it'll use 1/2 the material a printed 2x4 would.
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#5 Meaker VI

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Posted 27 June 2017 - 03:00 PM

Double post!

 

So I've changed the fittings around: out of the coil-mag, 3/4" coupler setup as before, 3/4" pipe w/ chamfered edge towards coil, 3/4" coupler, 1/2" coupler (T, in my rig), FWC.

 

It then fed ~65 rounds non-stop through the FWC and into my kids and/or the street. I'll need to hook it up to a longer coil to better check what the limit on loading is; I chopped my 30' coil because I thought it was the problem initially (and it might have been part of it). I'll also need ~200 short darts to try a full load with those instead and see if the capacity limit is due to the head friction/weight, column weight, or length friction.

 

Oh, I also picked up a snap-on 3/4" T-piece that works great as a breech door for now. I'll probably end up with either a Y or a custom-printed dart-loading door; a Y would be easy but I think I might be able to get a continuous loading-feed going if I interrupt the air flow just right.

 

Next steps are finding a bigger battery, figuring out a trigger for at least semi-auto, figuring out how to best make the coil mag into a swappable mag, and then to take it off the bench and put it into a shell. Or just print a custom 2x4 and use that.

 

Oh right, Jwasko I found and tried the thing you recommended - too tight. Even after drilling it out the 3/4-1/2" CPVC coupler wouldn't do anything.


Edited by Meaker VI, 27 June 2017 - 03:06 PM.

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#6 Meaker VI

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Posted 06 February 2018 - 01:55 PM

7D84A4FA-129A-46D3-8CB2-9D72CBFF14E4.jpeg

Triple post!

Loaded up the modified prototype with 180 short darts: it cleared them easily. I only have 200 short darts ATM, so Ill need to both make more and assemble a longer coil to test larger quantities.

This is definitely going to be better in an HMG/LMG role. Fire rate is fairly uncontrolled, and I have not been able to conceive a good fire control method that would not also require feathering the blower all the time.
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#7 TantumBull

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Posted 06 February 2018 - 02:11 PM

I wonder if a little spring hinged dart gate would help normalize firing rate. Think about those little hinges on a stock stryfe flywheel cage. The blower would still be easily able to overcome the springs and open the latch but it would allow a bit of a build up of force before the gates swing open, potentially lowering the fire rate (something we discussed as being useful). You can easily experiment with different spring constants and see if that affects your fire rate and control

If you wanna try this out I have a stock stryfe cage that I could just give you.
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#8 Meaker VI

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Posted 06 February 2018 - 03:52 PM

I'd be worried that something like a gate might wreck the magic and make it break. I'd considered a set of wheels or rails necking down the ID of the pipe as it approaches the FWC, but as it stands, I think my goal will be to get it working and feasibly war-ready and then mess with it to see if it can be made into a rifle-format instead of an MG-format blaster.

 

I forget who I was talking to, but somewhere I got an idea that I could probably split the blower feed with a diverter, hopefully rejoin it at the FWC (but if not just use multiple FWC's), and so enable a continuous fire rate much higher than any regular mag blaster with a number of mags that is sensible to carry. With just this one coil I'm already carrying 10 mags, so if the feed was split into two coils you'd have the equivalent of 20 mags onboard and with the help of a loader you could swap mags without ceasing fire. I could envision a three-four man team being able to load coils from loose darts as fast as the blaster could fire them. Oh, also relevant: This coil I'm using is ~$12 of material. So the MSRP of one Hasbro 18 mag provides 10 mags worth of capacity (in short darts; little under half that in long).

 

The problem then becomes whether my blower & FWC can handle that kind of sustained ROF, and I know it can't because it says so on the blower box (Forget exactly ho bad it is, but it wants something like 30 seconds cooldown every few minutes operation). I'd like to source a better blower, obviously a better FWC can be had because my current rig is just a bone-stock rayvan one.


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#9 TantumBull

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Posted 06 February 2018 - 04:36 PM

I doubt the gate would be an issue if done right. Do you have an estimate of how much force is generated on the lead dart in the mag? When I get home I'll measure the weight needed (plus the dart's weight) to open the stryfe gates. I would be really surprised if your blower can't generate enough force on the lead dart to open those gates. Plus the torsion springs are always replaceable to something with a lower constant.

I like the wheel idea. If you take it a step further, you could have automated gates via servos. That way you don't have to worry about active breaking on a DC motor spun flywheel. You could also program bursts really easily.

Both of these ideas can easily work in junction with the wye combiner thing (also great idea).

You know what I actually really like the servo gate. I'll get some servos and code something up. In place of a blower I'll use my lungs for now. I'll also test out the stock stryfe gate with my lungs, sort of like a blowgun with an afterburner.

As far as continuously running the blower, I'm guessing that's a heating issue. If you open it up and check what overheats (probably motor) you could slap on a heat sink and even add an active cooling fan. I have a spare stock Intel CPU cooler that I could donate to the project as well as some thermal compound.

Edited by TantumBull, 06 February 2018 - 04:38 PM.

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#10 TantumBull

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Posted 06 February 2018 - 05:57 PM

So I just tested the stryfe cage with stock gates on and it worked. With a 1/2" PVC tube I was able to blow the darts through the gate with minimal effort. The rate of fire was so high however that I'm not sure how much this will really control your set-up, but it certainly works. Theoretically the added pushback should slow things down some. I would imagine your blower can out perform my lungs so it shouldn't be a problem. Hmm now I need to buy a blower apparently...


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#11 Meaker VI

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Posted 06 February 2018 - 06:31 PM

So I just tested the stryfe cage with stock gates on and it worked. With a 1/2" PVC tube I was able to blow the darts through the gate with minimal effort. The rate of fire was so high however that I'm not sure how much this will really control your set-up, but it certainly works. Theoretically the added pushback should slow things down some. I would imagine your blower can out perform my lungs so it shouldn't be a problem. Hmm now I need to buy a blower apparently...

 

And 3/4" flexible ENT conduit. I linked the blower I used in the OP, let me know if you can't find it since it's been a year.


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#12 Meaker VI

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Posted 03 July 2018 - 05:11 PM

Link to video, cage modifications

 

Link to reddit thread on sunsetting development

 

The blaster works, but with other capacity advances in production blasters (adventure force command fire) and with my inability to get it working consistently reliably I have decided to halt further research down this track.

 

Not noted here is the requirement for this blaster to use a dart-stopping trigger. Tantumbull solved the problem with a servo, I solved it with a simple sprung lever tied to the main trigger with a string. This trigger prevents darts entering the wheels while they are spinning down, and also allows greater finesse over the ROF of the system.

 

If anyone in the future is interested in pursuing this line of development, please feel free to post asking questions or message me here or on Reddit. If I am no longer in the community, feel free to utilize my research.


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