265 replies to this topic

[CaptainSlug]

how is it going to open and close on demand?

The breech is actuated by the track in the middle of the gun just ahead of the dart hopper.

Edited by CaptainSlug, 26 March 2006 - 04:07 AM.

[SKIZ]

O that easy ay.
Cool sounds great and with your simplified explanations on how everything works... lets just say i have high hopes of this being one hell of a support weapon. All you have to do now is figure out how you can put a basic sight on it.
Jokes of coarse if this can do what your saying it will be able to do screw aiming just spray and pray.

For your plunger you might want to use carbon's idea of having a washer fastened to an end cap.

http://nerfhaven.com...?showtopic=6232

Seems that his plunger would offer alot of power.

Edited by SKIZ, 26 March 2006 - 04:16 AM.

[CaptainSlug]

O that easy ay.
Cool sounds great and with your simplified explanations on how everything works... lets just say i have high hopes of this being one hell of a support weapon. All you have to do now is figure out how you can put a basic sight on it.
Jokes of coarse if this can do what your saying it will be able to do screw aiming just spray and pray.

For your plunger you might want to use carbon's idea of having a washer fastened to an end cap.

http://nerfhaven.com...?showtopic=6232

Seems that his plunger would offer alot of power.

It is tempting to just copy his work which is known to produce positive results. The only downside is that in order to fit 1-1/4" PVC plunger tanks into this design I would have to go from 4 barrels to 3. I think I'll stick with 1" PVC for the tanks but I will use the fender washer.

In other news I just finished the materials list for this design.

Edited by CaptainSlug, 26 March 2006 - 05:32 AM.

[GeneralPrimevil]

Hey, what's wrong with three barrels?

That thing is going to be pretty neat. I like the idea for loading the barrels. I still don't like the spring operation, but that's because no matter where I go to play locally, something like this would be pretty stationary since we enjoy CTF a lot.

Good luck keeping up with Stefan demands. I see that thing using a lot in very little since it is fully automatic. Just shooting one or two rounds a second is pretty bad.

Have you thought of gearing down the barrel assembly so that the drill can run easier at a higher RPM? Something like 2:1 or 3:1 would be good. It would make your drill last longer as well.

[Denaeron 12]

Yes, gearing is a great idea, I support GeneralPrimevil's idea.
Also, you might think about using a Black&Decker drill, they're very nice, and not too expensive.

Other than that, beautiful work.

Edited by Denaeron_12, 26 March 2006 - 09:35 AM.

[Natch]

O_O.....I haven't tried to understand the concept yet (mainly cause I haven't read the whole thing) But I read "cordless Power drill" and "Gravity feed". I would make sure there's an easy way to switch batteries, and make sure there's a way to have a crapload of ammo without making it to hard to lug around. I also have an idea, try to design a clamp or something that could close around a bar or some other fixed object and allow you to use it like a nerf gun turret. That could help with defense if you're team is being pursued.

[GeneralPrimevil]

That can be accomplished with old driveshaft/tranny components. Take the yokes from the driveshaft and mount one to the output bearing on a tranny. Mount that whole thing on some sort of angle iron tripod. Then, take the other yoke (minus U-joint, that cross thing), attached to the gun, and use a bolt with a locknut to secure it to the yoke on the tripod. There ya go. You now have both elevation and yaw movement. Plus, if the bearing and yoke were welded along with the bearin and angle iron (all kinda have to be), there is a great amount of weight that mount could hold. I'd say that it easily could support over a hundred pounds, depending on support braces and what angles the legs extend from the bearing body.

[davidbowie]

For this to be tripod-mounted, he would probably have to build a different one, because as it is now, the handle is at the very front, and it's shoulder-fired. If you mounted that on a tripod, it would be very awkward.

It would be easier to build one with the handle at the back. This would be quite nice on a tripod.

[CaptainSlug]

Hey, what's wrong with three barrels?

Nothing really, but it's much easier to drill a precise 4-hole pattern than it is a 3-hole pattern and I was trying to keep this simple. I'm going to make a 3-barrel CAD model after I refine some of the parts further just to see if it has any functional advantages besides having one less barrel to make. If I were to go with 1-1/4" tanks and try to fit them into a 4-barrel pattern it would require shaving down certain areas of the outside of the tanks in order for them to fit.

I would make sure there's an easy way to switch batteries, and make sure there's a way to have a crapload of ammo without making it to hard to lug around.

Indeed. The powerdrill grip will have the removable battery in it and I already realized that the dart hopper will need a spring-loaded lid so that the darts stay inside.

For this to be tripod-mounted, he would probably have to build a different one, because as it is now, the handle is at the very front, and it's shoulder-fired. If you mounted that on a tripod, it would be very awkward.

You're correct. Fortunately the changes I'm making on the dart feeding system will allow me to get rid of the ejection port so I'm thinking about making the grip adjustable.

Edited by CaptainSlug, 26 March 2006 - 06:10 PM.

[CaptainSlug]

Alrighty, everyone is helping muchly with this process so thanks to all of you whether I used your feedback or not.
The revised dart feeding system is GREATLY improved and should tolerate much higher RPMs and it's much simpler to cut. The Green parts are stationary and the hook at the end of the hopper are 3 little hooks that go inside the gun spaced between the feeding teeth (yellow). The darts roll down one at a time and get stopped by the hooks. Then the feeding teeth grab the dart and as the teeth spin the dart falls down into the open breech.

That change conserved quite a bit of space and made the machining a little bit easier.

And the space saved made the 3-barrel w/ 1-1/4" tanks design possible.

I might actually go with 3 barrels because.
1) it will mean that only two plungers are engaging the advancing track at any given time
2) fewer parts to cut
3) less weight
4) higher plunger-tank volume
5) I can steal the part list from Carbon

The only downside is that minimum RPM is higher. whoop-dee-doo.

Edited by CaptainSlug, 26 March 2006 - 07:15 PM.

[GeneralPrimevil]

Now you are thinking better. Not that you were before, it's just that why take the trouble of completely designing every component from scratch? Use what other people have proved to work. I like to see that you have decided to do that.

Much better feed system. I mean, much better. So good, that I am going to take it if it works out well. Actually, I know that will work out well. I'm taking that, by the way, only for smaller projectiles and 6 barrels for a pneumatic thing I've been working on for the past month...
That top picture has the barrels rotating clockwise, by the way. I take it he chose to have the breach-end be pictured. Unless you really are Russian and have barrels rotating anti-clockwise...yes, some of their minigun did in fact rotate the wrong way. They have forward-back shotguns, too.

You forgot the most important reason why three barrels are better than one: there will be a better aesthetical appearance with 1/2" Sch40 barrels. Seriously...

Okay, that project of mine jumped up a notch. Time to complete the other two projects I have and try and finish some stuff by June...

[Denaeron 12]

It looks like the new feed system will work well.
I can't wait to see this finished!

And GeneralPrimevil, why the obsession with the ruskies?
Everyone knows that the barrels should go anti-clockwise, don't they?

[GeneralPrimevil]

Depends on if the perspective is giving or receiving massive amounts lead, er, solid core depleted uranium rather. Same thing as lead really, but...anyway, back on topic. If seen from the firer, then the barrels are moving clockwise, or so it was told to me. I dunno if the source was right, but it always seemed right to me. I really don't know though...



The Russians have the best firearms designs for simplicity, functionality, and real world performance. They are the definitive firearms manufacturers.

[CaptainSlug]

The tooth on the dart hopper can effectively be used from any direction provided that there's enough clearance between it and the rotating barrels and that there's something (in this case gravity) providing a small amount of push on the darts. So basically this design could be altered to use a weaker spring-loaded magazine.
The 1-1/4" tanks have made the internals more difficult to space so I had to go with a 45-degree entry angle at the 9 o' clock position for the darts.

In the present configuration the darts fire when they reach the 6 o' clock position. This provided far more room in the cycle (90 degrees) for the dart to reach the breech (at 12' o clock) and be loaded.

There's no particular reason I went with clockwise. Might be because I didn't want the dart hopper right next to my head (I'm right-handed).

And here's some semi-positive news: I need to study abroad for two months this summer which would upset the progress of things I was about to work on. So I have to postpone almost all of my other projects until I get back. This means I may start this soon instead of waiting several months. Not sure though because my life is a bit of a mess right now.

Edited by CaptainSlug, 03 April 2006 - 08:12 AM.

[CaptainSlug]

One last part that I decided to add to make bloody-well sure that the dart actually gets fed into the breech is this set of ramps which are inserted from a "servicing port" on the left side of the gun. They're the orange part in the image.



These are stationary and will wedge the dart into the open breech at the right point in the cycle. If any jamming occurs (if you accidentally put the wrong size dart in the hopper) you can pull these ramps out through the side and advance the gun in reverse to see what the problem is and correct through the port to avoid having to remove the hopper full of darts to get the gun working again.
As shown in the animation These three parts combined should allow for ONLY ONE DART to enter the gun at a time and will make sure it reaches the open breech at the 12 o' clock position.

Edited by CaptainSlug, 03 April 2006 - 08:12 AM.

[murakumo32]

Seems highly possible, go for it (duh). Hope life works out so you can work on this.

[boltsniper]

The Russians have the best firearms designs for simplicity, functionality, and real world performance. They are the definitive firearms manufacturers.

I would give this to the Germans.

Russian engineering is just so sloppy and half assed. I had an opportunity to look at some cold war era Migs a while back. The simplicity is there and you gotta give them props for that but the workmanship is amazingly bad and they are way over designed. They don`t use flush rivets, the panel lines ar not flush and have huge gaps. They use a lot of steel in teh airframe which make the whoel thing very heavy which they make up for with brute force.

Captainslug,
This is pretty damn interesting. I really don`t see anything that isn`t going to work. It will be tough to fabricate but I think you should be able to handle it given your case experience.

The only thing I see that may be iffy is the hopper. If you plan on using darts with no shells then you may have some jamming problems. Darts are light and not smooth so they will likely bind on eachother where they go single file. Placing a weight on top of the darts inthe hopper may help but I still foresee jamming problems with bare darts. Also the darts may nto feed fast enough to keep up with the rotation of the barrels and the feed teeth may cut the dart up as it passes by.

I think three barrels is a good idea, if for nothing else, it will keep the overall size down. Especially since you are planning to use 1/1/4" PVC for the plunger housings. You may want to go down to 1" plunger housings to keep the size down.

Very interesting though. You got me ponfdering this as well. When do you plan on starting fabrication?

[CaptainSlug]

I was highly concerned with trying to avoid having the dart feed mechanism cause the darts in the hopper to jump around due to contact and interaction with the teeth but the newest design (as far as I can tell now) has eliminated that problem by basically working to lock a single dart in a fixed position before engaging it. The darts have plenty of time in the cycle to roll down the 45 degree slope before they get picked up.

The teeth will be made out of heavily sanded/rounded off polycarbonate sheets and there should be enough surface area on them to safely handle the darts without any wear and tear. Just keep in mind that there are parallel sets of teeth, 2 or 4 on the rotating part and 3 on the stationary parts.

I've left enough path width tolerances to prevent squeezing and assuming I make the darts correctly I shouldn't have any jamming problems at lower speeds. It will take some experimentation with a mock-up to see what the speed ceiling is on the dart feeding system.

Yes 3 barrels with 1-1/4" tanks is a little cozy but more than manageable as long as I use bushings instead of caps.

It's going to be much easier to make than what I was working on and I'd like to start work on this sometime in the next two weeks. I'll need to find out the results of my blood work from the doctor first though because if it turns out that I do have Lyme disease (there's a serious outbreak of it in Loudoun County) then I may end up getting knocked on my butt by some really nasty antibiotics to get rid of it.

BTW, thank you for giving me all those spring dimensions. I'm hoping to use the AR15 spring with this gun as well.

Edited by CaptainSlug, 27 March 2006 - 01:35 AM.

[CaptainSlug]

Everything is ordered with only minor alterations. I will be using PETG instead of brass for the sliding barrels. It will require a little bit of lathe work but will be more cost effective.

Edit: Everything arrived, but I still need to get ahold of the springs.

Edited by CaptainSlug, 03 April 2006 - 07:49 AM.

[CaptainSlug]

I'm STILL waiting for springs to come in the mail. But I'm researching different drive options.
Here's the motor I will probably use: 12VDC multispeed windsheild wiper motor.
Powered by this battery: 12v 7ah 6lb
And charged by this charger: 12V 7ah barrel plug

Much cheaper than a power drill and it will give me a longer battery life. I'll have to wire up a rotary switch as the speed selector and I need to find a trigger switch.

Edited by CaptainSlug, 06 April 2006 - 12:36 PM.

[skiermon]

All that hardware looks pretty heavy... Otherwise, this thing looks sweet.

[CaptainSlug]

Yeah, this thing is going to be a real beast. The current estimated weight total is between 10 and 15 pounds. Having this thing setup for a shoulder-mounting position is looking more and more likely.

Edit: HOORAY!!! The springs arrived. Now I can get to work.

Another Edit: Now that I have the springs in my hands I realized that I'm short one or two parts and that the polyster tubing is not going to work as a breech/barrel in this configuration. So I had to place another order which will arrive tomorrow.
The gun is now looking to be around 36 inches in total length.

Edited by CaptainSlug, 06 April 2006 - 04:20 PM.

[CaptainSlug]

The motor, battery, charger, and switches are now ordered as well.
While I'm waiting for the last few parts to come in the mail I decided to work out the placement of the motor and battery. Due to the weight of this gun it's going to be most comfortable as a shoulder-mount. I think it will prove to be less cumbersome this way and will make aiming and carrying it less tiresome.


Also, in light of what GeneralPrimevil was taking about I'm going to wire the battery with a locking barrel plug power connector to make it easy to swap out the depleted and charged batteries. And when a battery is not loaded I have a 12V 5A power supply that I could use to power the gun in a corded/stationary manner. The motor and battery I have chosen when used together should offer 4 to 6 hours of battery life. Plenty of time for the spare battery to charge.

Edited by CaptainSlug, 06 April 2006 - 07:08 PM.

[z80]

You could also mount it to a car or maybe a golf cart, then attach it to the electrical system. Looks like a nice little design, hopefully you'll make it, and blow us away.

[CaptainSlug]

Yes that's more than possible since it will be able to connect to any 12V source that can provide enough amperage. I don't specifically have any plans for a cigarette lighter adapter though.