18 replies to this topic

[bjack]

Hey does anyone think that this idea for a semi-auto nerf gun would work? Thank you.

[The Crackerjack Man]

Looks like it could work. You just have to go for it and see how it goes. Thats the best I can tell you. And use pvc glue so you dont have an end cap blowing off at anything or yourself.

[bjack]

hah yeah thats already happened to me. Thanks.

[nerfturtle]

It makes no sense to me. In the "30 psi firing tank", there is nothing inbetween it and the barrel, so it technically couldn't hold 30 psi. In the "200 psi holding tank" it is separated from the other tank by a check valve, which is a valve that lets air go one direction but not the other. So, that would make it either just hold air until it all leaked out, or it would just flow through, into the other "tank".

[privateer]

It could work.

BUT

it would be
1) unwieldy
2) dangerous (PVC @ 200PSI? Not near me)

Ergonomics and simplicity are omnipresent factors. Just build a snap.
Good idea, though.

[Forsaken angel24]

It would also be hard to pump something up to 200 psi.
I doubt even I could do that.

[Shadow 92]

Sorry, but it wouldn't work the current setup. The way a semi-auto works is a burst of air is released at a regulated pressure and only for a specified amount of time.

I see in your design you have a check valve for preventing back flow. That's necessary for building an airtank. It's location is also ideal in that it is directly connected to the firing tank. If it were connected to the front of the holding tank, then the tubing (and not the airtank) would be put under excess pressure. Those are the strong points of your design. The weak points are it's lack of a valve that allows control over the amount of air being released at a time, the pressure is unregulated from the holding tank to the firing chamber, and the pressure of the holding chamber is both too high for standard PVC parts and unobtainable with a regular bike pump.

What you can do is combine existing products to create a semi-auto tank. This valve (by Doom and Dr. Nerf) allows for controlled burst of air. And this design by CS allows you to store massive quantities of air at a high pressure and then be regulated down to a practical firing chamber. So all you would have to do is connect the tank to the valve and you would have a semi-auto valve and tank.

[OfAllTheNerf]

It would also be hard to pump something up to 200 psi.
I doubt even I could do that.

And this is coming from the guy who can cock a modified LS with his left hand (unless of course you're left handed, but I can't even do it with my right)?

On topic, I have the same point as shadow. By what I can see it looks like there is nothing controlling the airflow. Therefore the amount of air allowed to escape would be decided by the trigger pull.

-OfAll'

[puggy]

You can use a shock absorber pump to fill it up that much.

[Shadow 92]

Hey puggy, do you know how shock absorber pumps works?

[bjack]

Well i whipped up this design in paint in like 2 mintutes yesterday and just didnt draw in the valve to the barrel. I figured that it was implied. But i agree that 200 PSI is a little much that was just a number.

[wldworld]

Also, in your diagram, you need to replace the check valve with a regulator set at 30 PSI.

Edited by wldworld, 11 July 2007 - 12:50 PM.

[The Crackerjack Man]

It would also be hard to pump something up to 200 psi.
I doubt even I could do that.

And this is coming from the guy who can cock a modified LS with his left hand (unless of course you're left handed, but I can't even do it with my right)?
-OfAll'

Im right handed and I can pump a BBB modified LS with my left. Is that realy that hard?

And if you search bjack you can find a paint that I did and it has a working sem-auto design.

[bjack]

Alright so heeding Shadow's advice i drew up a new design for the gun. Once again feedback would be nice. Thanks, especially to Shadow for his advice, and Dr. Nerf and Captain Slug for their designs.

[Doom]

That sounds like it would work.

However, one thing I want to note is the difficulty of building the Dr. Nerf valve (and FYI, I didn't have much to do with the construction of that valve, but many thought of the basic design many times before his construction). You'll have to do a lot of sanding and the end product isn't the most reliable. I have redesigned the valve myself to make it much easier to fabricate from threaded rod, nuts, washers, and rubber washers. This new version also is easier to pull and seals better. I anticipate completion of the Nerf gun (including air regulators and few other features) within the next few weeks given my free time. I would not recommend constructing the valve as described by Dr. Nerf due to the vast improvements in construction I have made in my new version.

Edited by Doom, 12 July 2007 - 08:45 AM.

[Shadow 92]

Alright so heeding Shadow's advice i drew up a new design for the gun. Once again feedback would be nice. Thanks, especially to Shadow for his advice, and Dr. Nerf and Captain Slug for their designs.

Your welcome. I'm assuming that the design is a simplified version of the valve. The real valve is composed of many more pieces. And what do you intend to do with the semi-auto tank after you build it? If you're thinking about making a semi-auto gun then you would have to incorporate something that loads the dart with each trigger pull in addition to firing it. And that's something that requires much more work.

Doom, can you post picks of the redesigned valve?

[bjack]

Im not sure yet. I was comtemplating different ideas and i was thinking just using a simple sliding breech and either a gravity fed or spring fed clip just to see how the gun functions and if everything works out go into production of a feeding system that just uses the trigger. Does anyone have any ideas on how i could achieve this goal?

[Shadow 92]

I'm actually designing a semi-automatic gun right now. I really don't want to release any plans yet, but I'll give you the links to the places where I got the idea from.

One
And Two

[Doom]

Shadow 92, I can not provide images of the valve at the moment due to time constraints. The gun will be done within a few weeks however and the latest you will see the valve is then. I'll let you know if I can get some pictures in the next few days. I already have provided a description that is detailed enough to construct it, but I doubt most people here could work with only a description, so pictures are necessary.