101 replies to this topic

[CaptainSlug]

Several threads have been discussing potential solutions for more efficient full-auto systems that would allow for sustainable fire. During one I had an epiphany that allow me to simplify the regulation of the supply tank pressure so that an electric pump could be used to keep the tank at a mechanically specified level. Here's the diagram that helps me conceptualize the setup.

A Pulse-Width Modulation circuit will be needed to control the cycling of the solenoid which will trigger the valve. The valve is spaced so that each cycle will equalize the charge tank with the main tank, the charge tank will seal, the breech-actuator will close the breech, and then the dart will fire. And the reverse will let a new dart chamber.

I used this to shop for the appropriate parts and then replicate those parts in CAD. It took quite alot of time to decide upon parts and then work out how best to arrainge them in the best functional setup that also allowed for a workable weight balance. After several days of CAD work I now have this mostly-complete model.

29 inches long and presumably around 20lb. Weight balance is centered slightly behind the grip. 20-round clip (weakly spring-loaded). No shells. The "trigger" right behind the clip is a clip eject. The clip keeps the darts inside when not loaded in the gun.

The main tank is in front and may need to be enlarged to allow for more capacity. The pump is in the center and the battery is in the very rear.

The ideal pump I've found is a 12v diaphragm pump meant for pumping water (but also works with air) in recreational vehicles. It doesn't draw too much current, which was an issue with piston-pumps which drew a minimum of 10 amps.

I will eventually get around to making this but I'm not exactly sure when.

The gun is rather large. A manual pump and a smaller battery for just the solenoid could be used to make this a much smaller and lighter gun if I decide that I want something more portable. Or better yet, maybe I can find a smaller more efficient pump. I haven't really decided yet.

Edited by CaptainSlug, 09 May 2006 - 11:54 AM.

[ompa]

It'll be tricky to get the exact length needed to allow enough time for the breech to open and close before the charge tank goes off though.

Other than that, good luck man! Your designs are incredible.

~ompa

[CaptainSlug]

Oh crap, you just gave me an idea...
It might require a completely different circuit though.
Basically instead of using a PWM circuit to change the timing of the solenoid I could turn the breech-actuator into the charge tank. The breech will be closed once the charge tank is equalized with the main tank.

The solenoid will simply switch charge tank connection between the barrel and the main tank. The timing on the solenoid will be dependent upon the breech actuator being in the closed position (pushbutton trigger). The solenoid will turn off once the breech actuator reaches the open position (pushbutton trigger). The circuit could be adjustable by putting a delay between cycles.
I'm making a new version of the CAD to reflect the changes.

Edit: After some consideration I've decided to make this a manual semi-auto weapon

The trigger replaces the solenoid and the hand-grip pump replaces the motorized pump. Each trigger pull will fire a dart and the release will then cycle the next one into the chamber.
There's potential to shrink the firearm further and make it a perfect pistol so I'm thinking about alternative pump placement options.

Edited by CaptainSlug, 09 May 2006 - 02:42 AM.

[CaptainSlug]

My designs never remain static. Here's the pistol version that has identical internal workings but only has a total length of 14 inches and holds 10 darts in the clip.
Ompa, I blame you.
This will be fairly cheap to make and I can make a few from a single part list.



I just need to add the simple trigger mechanism. I may be making this instead of the sledgehammer.

Edited by CaptainSlug, 09 May 2006 - 12:00 PM.

[pat 1st Lt]

CaptainSlug,

You're designs never cease to amaze me. You're ideas are always extraordinarily intriuging.

This is a fairly trivial and non-indepth comment, but may I suggest placing the pump on the top of the gun, and having it move back twoard the shooter and then be pushed forward?

I worded that poorly. Let me explain: put the pump tube on the top of the gun, and have it move rearwards twoard the shooter, then compress the air on the forward stroke. Placing the pump handle on top would make it much more pistol-like, rather than a small SMG.

Just imagine the Maverick slide handle as a pump, except with a longer stroke. As in, pull it back, push it forward, pull it back, push it forward, pull it back, push it forward, leave it forward so it's flush with the gun's casing and all neat and tidy, and then fire.


It's a fairly trivial suggestion, but I thought I'd throw it out since rearward-stroke pump pistols always annoyed me.




Sincereley,
Pat

[GeneralPrimevil]

After saying that,



Then after picking my faw up from the floor, I decided to post.

Wow man, I mean....I can't say anything.

That is awesome. Defintion of awesome is that.

Did I mention you are insanely fast with Alibre? I think I should go make something on it now...

Good luck.

[CaptainSlug]

It's a fairly trivial suggestion, but I thought I'd throw it out since rearward-stroke pump pistols always annoyed me.

Hmmm, the current pump pumps backwards from the front and you leave it in the pumped mode when firing. Interestingly enough there's alot of space left in the rear of the gun so putting the pump back there wouldn't be too difficult. I could use the breech actuator as a slide.

Let me see if I can get it to fit and work. At the very least it will make the gun smaller.

Edited by CaptainSlug, 09 May 2006 - 03:42 PM.

[Enigma1313]

Wow..your designs are truly awe-inspiring. Though I am as unexperienced as one can be in the homemade realm, this design is so comprehensibly genius, it deserves the title "Comprehensively Genius." I'd really like to see this thing come to fruit, for I believe it could have the same impact on the NerfWorld that Bolt's now-legendary FAR has had.

[CaptainSlug]

Here's the result of what Pat suggested.


And here's a highlight of the parts you pull-push to pump.

It definitely makes the gun less bulky. I'm undecided on whether or not it's an ergonomic improvement to pump forward. It wouldn't be too hard to reverse the pumping direction so that pulling backwards on the pump pressurizes the tank, and then the pump could return to the neutral position with a spring.

Did I mention you are insanely fast with Alibre? I think I should go make something on it now...

Yeah, I have way too much practice with 3D. Once you figure out what materials you're using and their dimensions it gets really easy to move parts around. Most of my designs involve 3/16th" thickness sheets of plastic because I have so many scrap sheets.

Edited by CaptainSlug, 09 May 2006 - 05:26 PM.

[ompa]

So at this point it's a manually-powered semi-auto?

My issue with that is that you're going to need to be constantly pumping it, for the volume of air you're going to need to get the whole thing to open the breech, AND fire the dart is going to be considerable. Unless you plan to install a tank where you have very high pressure and regulating the pressure flow out of that tank to a lower pressure, so you have enough air. Otherwise, you're going to find yourself pumping that thing more than shooting. Unless you have a really, really efficient and low-friction bolt.

Oh, and I am by no means trying to bash your designs; I'm just trying to find all the holes I can so that when you build it you won't have to go through as many revisions, since building revisions for this type of thing must be a major pain in the ass.

~ompa

[JSkater]

I'll believe it when I see it fire.

[CaptainSlug]

I won't get anywhere without criticism so keep it coming.

My issue with that is that you're going to need to be constantly pumping it, for the volume of air you're going to need to get the whole thing to open the breech, AND fire the dart is going to be considerable.

Your first reply gave me a revelation. If the breech-actuator also acts as the "charge tank" you don't need any extra volume. The breech returns to the open position after the dart is fired thanks to a weak spring.

Obviously a prototype would need to be made. But here's how the internals work. Red is the supply line from the main tank.

I still have plenty of time to contemplate this. But the spring is weak enough that it won't be able to push the breech to the open position until the pressure has nearly equalized with ambient. At which point the dart should already have left the barrel. And the main tank will slowly lose volume, but should have enough volume to fire a few darts in succession. Could be solved by using a larger tank or a higher main tank pressure.

And if all comes to pot and this doesn't look promising this design atleast forced me to figure out how to make a workable spring-loaded magazine. I can adapt the configuration I came up with to work with spring-plunger guns.

Edited by CaptainSlug, 10 May 2006 - 12:45 AM.

[ompa]

Well, assuming you can find the right spring, I no longer see any issues then. Best of luck man!

~ompa

[pat 1st Lt]

I still have plenty of time to contemplate this. But the spring is weak enough that it won't be able to push the breech to the open position until the pressure has nearly equalized with ambient. At which point the dart should already have left the barrel.

Good luck finding the right spring. very few places sell springs like the kind you're thinking of. You'd probably have to special order it. But, then again, it might not be that hard to find the right kind of spring.

Being inept at reading on-line blueprints, I may have the dimensions all wrong and you could just use a NiteFinder spring, or something.


Well, yeah. It looks like this is very plausible now. That spring idea should work out well if you can find the correct spring. It'll still take a lot of pumping, but not such a large amount that it'll be inefficient in a war. If this works out, you should try to adapt this magazine and breech to some plunger guns (Unless you don't want to. I just think plunger guns are over-all better than pump guns).


Well, good luck building this (If you do decide it won't be too hard/laborious to build). It should work out to be pretty cool.


One question though: Magazine catch. How's it held in? Just friction? Or is there a locking mechanism to hold the magazine?

Just a quick thought: magazine spring. The new edition BBB's have a very large, but very weak spring in their air-restrictors. If stretched to the correct length, and with a lightweight follow attached, they work well as magazine springs. I used one in my interpretation of the Bacon Big Bad Bow. But, since your's is ten rounds, you might wanna double up on springs.



As I said before, best of luck. I hope you actually build a fully functional one. It's just soooo cool.



Sincereley,
Pat

[CaptainSlug]

I wish I could find a cheap 12v air pump.

Good luck finding the right spring. very few places sell springs like the kind you're thinking of. You'd probably have to special order it. But, then again, it might not be that hard to find the right kind of spring.

It'll still take a lot of pumping, but not such a large amount that it'll be inefficient in a war. If this works out, you should try to adapt this magazine and breech to some plunger guns (Unless you don't want to. I just think plunger guns are over-all better than pump guns).

http://www.mcmaster....9/9657K820L.GIF
It has a Load of only 2 pounds @ 1/3lb per inch.If that's too weak these are so small around that I can just add another using a spacer (if I need 4 pounds). The magazine and breech-actuator are designed to use this spring.

If this works out, you should try to adapt this magazine and breech to some plunger guns (Unless you don't want to. I just think plunger guns are over-all better than pump guns).

Already working on that design actually.

One question though: Magazine catch. How's it held in? Just friction? Or is there a locking mechanism to hold the magazine?

Blue = clip
Light blue = dart retainer tooth/sleeve
Red = clip retainer
Green = gun body and unlocking tooth
You simply retract the clip retainer and pull the clip out. The dart retainer tooth and sleeve will retract as the unlocking tooth gets out from inbetween it and the body of the clip.

Edited by CaptainSlug, 10 May 2006 - 07:50 PM.

[pat 1st Lt]

One question though: Magazine catch. How's it held in? Just friction? Or is there a locking mechanism to hold the magazine?

Blue = clip
Light blue = dart retainer tooth/sleeve
Red = clip retainer
Green = gun body and unlocking tooth
You simply retract the clip retainer and pull the clip out. The dart retainer tooth and sleeve will retract as the unlocking tooth gets out from inbetween it and the body of the clip.

Well then. It seems then that this will work out, unless any unforseen problems occur during the fabrication. I doubt anything too serious would occur, though.

Oh, on a side note: Jesus! I wish I could just draw stuff up as quickly as you do. It must be really easy to explain what you're thinking. Maybe if I could draw up diagrams I'd do more home-mades. What program do you use to draw these things up? Was it expensive? Does it take an inordinant amount of time to learn to use?


And as we've all said countless times by now: Wow. Keep up with the amazing designs, and I hope to see a finished product some day soon. Best of luck.


Sincereley,
Pat

Edited by {SF3G}pat 2nd Lt., 10 May 2006 - 07:50 PM.

[CaptainSlug]

I use Alibre Xpress for CAD work, which is the free version of the full package.
http://www.alibre.co...sign-xpress.asp

It's very easy to use, fast, and has 80% of the functionality of the full software package while still being an unlimited trial version.

To make the little color-coded drawings I just doodle on-top of an Alibre Xpress screenshot using Paint Shop Pro 5. Alibre Xpress does let you make dissection images if you need to so I could do it that way if I didn't need to color-code my drawings.

I'm hoping to win a cheap portable air compressor on ebay which would negate the need for me to manually recharge the tank. It alone won't make the gun full-auto (for that I would need a solenoid) but it will make the gun easier to use. I'm not sure if I care too much about full-auto for this gun. Atleast I have the method of doing so figured out. We'll see if I change my mind on that in a few weeks though.

I'd also like to try my hand at designing a regulator. But it may just be cheaper to buy an adjustable one from harbor freight.

Edited by CaptainSlug, 10 May 2006 - 11:32 PM.

[roadrunner]

Here is a fairly cheap and very portable battery powered air compressor. Airman Aircompressor

Edited by roadrunner, 16 May 2006 - 08:53 AM.

[CaptainSlug]

Here is a fairly cheap and very portable battery powered air compressor. Airman Aircompressor

Haha, yeah I'm supposed to be getting one of those in the mail through eBay soon.

[SirTofu]

whoop de doo, fancy pictures. You have been drawing fancy pictures for a long time now, start attempting to build one, or stop posting these "idealist" designs.

[ompa]

He's already posted pictures of his in-progress CSHG, which is rather impressive. Read up before you start bashing him.

EDIT: In my rather upset state, I forgot to post WHY posting such designs is helpful in the first stages of building a very complex design, which Captainslug covers in the post below this. Feedback is very important, so others might identify problems that you may have missed. And when making something this complex, it's nice to only have to build it once, without mistakes.

~ompa

[CaptainSlug]

whoop de doo, fancy pictures. You have been drawing fancy pictures for a long time now, start attempting to build one, or stop posting these "idealist" designs.

Solving potential problems prior to touching your materials is the best way to save money and avoid waste. As I stated in the first post I'm already working on CSHG and a host of other projects so this project isn't a priority. I simply wanted to post my designs to get valuable feedback which will allow me to refine my designs further.

[Flaming Hilt]

Yes, yes, and yes. Pre-designing helps me to gut out errors, and most of my designs have actually been thrown away because they weren't very feasible.

But, back to relevance (is that a word?), you just gave me a great idea for a clip system... *gets to work.*

THAT is a nice compressor. I've been looking for one like that for a while. Much thanks to whoever dug that link up!

[davidbowie]

Hold your horses there, FH. The compressor is small and battery-powered, but the output is HORRIBLE. It says that it can fill a standard tire to 35 psi in around 8 MINUTES. That's a LONG time. I realize that most projects wouldn't use a tank quite so bit, but it would still be excruciatingly slow to fill most anything.

[Flaming Hilt]

...

*forgot to read specs...*

...

*cries.*