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Unread postAuthor: jackssmirkingrevenge » Mon Dec 13, 2010 6:17 am

Looking good! looks like the finished article will look a little like the Tavor :)
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Unread postAuthor: Gaderelguitarist » Mon Dec 13, 2010 11:22 am

Why not build one, I did


Because I am less than proficient with electronics and coding. I could no doubt build the physical structure, but that's all it would be.

Are you going to do any external scalloping with your laminations? You could really get some nicely contoured areas if you wanted to.
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Unread postAuthor: evilvet » Mon Dec 13, 2010 2:48 pm

jackssmirkingrevenge wrote:Looking good! looks like the finished article will look a little like the Tavor :)


I hadn't seen that one.

The original inspiration was the AUS Steyr F88 as used by our boys and girls to win friends and influence people around the world.
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Unread postAuthor: evilvet » Mon Dec 13, 2010 2:55 pm

Why not build one, I did


Because I am less than proficient with electronics and coding. I could no doubt build the physical structure, but that's all it would be.


Seriously, I am no electronics buff; I follow the manual and occasionally fry something, often spectacularly. Anyone who roams these forums is obviously mechanically adept and willing to have a go. The structure is simple and the electronics are all off the shelf. Being Stateside you have the added advantage of paying about 20% of what we do for the stuff as well.

Are you going to do any external scalloping with your laminations? You could really get some nicely contoured areas if you wanted to.


As I add each lamination I am shrinking the dimension by about 10mm, that way I will finish with a nice shape that I can fill and sand.

Cheers
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Unread postAuthor: jackssmirkingrevenge » Mon Dec 13, 2010 2:56 pm

evilvet wrote:The original inspiration was the AUS Steyr F88 as used by our boys and girls to win friends and influence people around the world.


Well put :)

The profiles are similar:

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Image
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Unread postAuthor: evilvet » Tue Dec 28, 2010 8:48 pm

Hi

I am having some issues with the magazine feed and am looking for suggestions.
My original design used a horizontal mag under the barrel with a spring loaded feed but I am not happy with it.

I tried a simple T-breech but to get any decent capacity I have issues with the length of the spring required. The same goes for a bottom feed mag, i still need a spring that is too long.

I am leaning towards a gravity feed magazine from the top and then using the solenoid to push the round sideways into the airstream.
The problem I see with this idea is the round will then have to travel through a 90 degree bend to enter the barrel.

Another idea is to use a mag on a 30 degree angle from the rear of the stock that intersects the barrel / breech and use a pull solenoid rather than a push. That means the breech would be blocked in the normal position, then the solenoid can retract allowing rounds to flow. That of course means continuous fire as long as the trigger is held down, rather than the single shot concept of my original design.


Any thought appreciated.

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Unread postAuthor: evilvet » Wed Dec 29, 2010 3:28 am

evilvet wrote:Hi

I am having some issues with the magazine feed and am looking for suggestions.



Replying to own thread.
Not good.
Need to get out of workshop.
Anyway................

Could this work ?
Instead of using springs to keep the mag pressurised, why not use air pressure?

Lower chamber holds the rounds, at rest they can rattle around and the solenoid plunger is in the lower position.
I use a two stage trigger pull, the first opens the air valve and pressurises both the barrel and the mag. Rounds are pressed forward, one is now resting above the plunger.
When the second stage trigger fires, the plunger rises, pushes a round into the air stream and fires.

Release the trigger and the system is at rest.

Yes I use a lot of air but I am running this from a 40 litre fixed tank so I don’t mind so much.

What do you think?
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Unread postAuthor: jackssmirkingrevenge » Mon Jan 03, 2011 6:29 pm

evilvet wrote:I am leaning towards a gravity feed magazine from the top and then using the solenoid to push the round sideways into the airstream.
The problem I see with this idea is the round will then have to travel through a 90 degree bend to enter the barrel.


Why not?

Image

sounds like it would work well feeding from a hopper.
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Unread postAuthor: evilvet » Tue Jan 04, 2011 12:46 am

Yeah, I get you (I think)
Side mount the solenoid and offset the magazine ?
The slope will also act as a detent and stop misfeeds ?

I tested a relay bridged with 500uF capacitors over the coil, the solenoid then pulses at about 4/sec, gives the semi auto effect talked about previously. Press and release for one shot, press and hold for 4 RPS.

Thanks JSR
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Unread postAuthor: jackssmirkingrevenge » Tue Jan 04, 2011 2:28 am

evilvet wrote:Side mount the solenoid and offset the magazine?


Basically, the solenoid pushes individual BBs into the barrel, it would be good to have some sort of detent between the magazine and the hole in the barrel though, or at least a magnet or similar to prevent misfeeds, better than just the slope.
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