22 replies to this topic

[cheesypiza001]

This design is now obsolete. Check here for an updated version.

This is mostly a proof of concept and is also for testing purposes.

After seeing this post by southpaw, featuring a true semi-automatic AT2K, I became inspired to create one of my own (well, at least a variation of it). I read that he used a valve from a super soaker, which I did not have, so I set to work on creating one from a hornet trigger system. This is not a complete writeup, but the pictures will hopefully suffice.

This is the basic idea of the whole thing.





When the trigger is partially pulled, the valve quickly shuts closing the path for the air to reach the tank, then when the trigger is pulled the full way back, the tank is fired. This means that whenever the trigger is in the un-pulled position, the air from the bladder will rush in and fill the tank. However, once the trigger starts to be pulled backwards, it closes the bladder. This system makes the whole semi-auto system much more efficient. By employing this concept, no air is wasted in the entire process of firing and refilling.


Here's the writeup part of this topic:

1. Cut your Hornet trigger system to look like this:




2. Fill the shown holes with hot glue.



(middle hole in the second pic)




3. Drill a hole through the check valve in the part of the trigger.




4. (This next part is optional. If you would like to install a PSI meter, then do this, but if not, then just fill the hole with hot glue.) goop a little stub of vinyl tubing the next size up from whatever vinyl tubing you usually use. This will act as a coupler for the vinyl tubing that connects to the PSI meter.




5. Cut off the heads of two hornet triggers.






6. Find a long piece of metal rod. The diameter of the rod should be smaller than the diameter of the trigger heads. Drill a hole in both trigger heads that is as large as the diameter of the metal rod you chose.




7. Slide both heads onto one end of the metal rod and goop them in place.




8. Wait for Goop to dry then apply the lubricant of your choice (I used lithium grease) to the O-rings, and insert the new trigger into the tube.


Your trigger system is now complete!





This is the final setup that I will employ in my soon to be primary. Though I pretty much revealed all of it, the rest is a surprise...



Closeup:



The above picture is once again just a proof of concept. When I actually put this stuff into the Firefly shell, I will make everything more permanent.


Feel free to post with any questions, comments, or suggestions. Thanks.

Edited by cheesypiza001, 25 December 2009 - 12:53 AM.

[nerfer63]

very good*evily laughs*.


N63

[atomatron]

Interesting, I entertained the idea of a semi auto blaster a while back, your design is pretty similar to the first design I came up with. The second design will someday be sported as a conglomeration of overkill.

Nice work.

Edited by atomatron, 15 November 2009 - 08:14 PM.

[Possemhunter]

I love how you did this. This has to be the simplest semi auto configuration I've seen that looks like it works. Great job.

[Hipponater]

Very nice. A good idea with solid execution.

I'm interested in how the ranges change with how many shots you do in succession, however. Is there a big drop, or a slow consistant decline, if any? I've never dealt with or seen a magstrike pump, so I don't know how well it refills the tank.

[TantumBull]

The mod is cool and all, but there is one thing that really stood out tome in this thread. When I saw the title, I was like, well shit, some asshole connected a paintball tank to a big salvo and is calling it's nerf gun. Then I saw the pump and the MS bladder. Fucking props on not trying to ruin this hobby. And as I Said, your setup looks great but thisis what stood out to me.

Edited by TantumBull, 15 November 2009 - 10:01 PM.

[freewave04]

So...

Does it work?

[Bedhed117]

Thank you a million! I was in the process of building a semi auto and this saves me several hours of frustration trying to build my own design for a valve.

[Phibonnachee]

Wow this is a really neat idea, and I just happen to have a broken hornet to use. I can see guns with rotating barrels that rotate from the trigger pull to have a great benefit from this (maverick).

[cheesypiza001]

very good*evily laughs*.


N63

Thanks.

Interesting, I entertained the idea of a semi auto blaster a while back, your design is pretty similar to the first design I came up with. The second design will someday be sported as a conglomeration of overkill.

Nice work.

Good luck with your design and thanks for the compliment.

I love how you did this. This has to be the simplest semi auto configuration I've seen that looks like it works. Great job.

Yeah, I was looking for something pretty simple. However, I have a completely different approach to a semi-auto valve in the back of my mind that would be even much simpler than this. I'll keep you guys updated.

Very nice. A good idea with solid execution.

I'm interested in how the ranges change with how many shots you do in succession, however. Is there a big drop, or a slow consistant decline, if any? I've never dealt with or seen a magstrike pump, so I don't know how well it refills the tank.

I haven't really gotten that far yet. Every time, the back of the magstrike bladder blows off after I complete the second pump (Even though I clamped it on). Also, it has a titan pump, not a magstrike pump.

The mod is cool and all, but there is one thing that really stood out tome in this thread. When I saw the title, I was like, well shit, some asshole connected a paintball tank to a big salvo and is calling it's nerf gun. Then I saw the pump and the MS bladder. Fucking props on not trying to ruin this hobby. And as I Said, your setup looks great but thisis what stood out to me.

Thanks man. I'm all for keeping Nerf what it is, and so because of that, I think I may have to go have to using my SM1500 after completing this project, as it already seems to be "unfair." I was planning to add an airtight seal between the tank and the turret, replace the barrels with 12" PETG, add a spacer plate, and make it rear-loading. However, I feel that this could have a very negative effect on the mood of the game.

So...

Does it work?

Haha. Good question. As explained a few responses up, I have not yet been able to get it past two pumps. I will keep everyone updated so check back soon.

Thank you a million! I was in the process of building a semi auto and this saves me several hours of frustration trying to build my own design for a valve.

I would not suggest following this writeup until I have completed this design and made sure that it works 100%. Most of this lies in me getting a hose clamp to secure the bladder to the plastic end piece of the bladder.

[Zorns Lemma]

Unless I'm mistaken in estimating the draws, you're going to have some air leak when you open the 2k tank valve and close the bladder->tank valve.

Hopefully because of the difference in ID between the valves, it won't be much, but you should look into making the "plug" on the trigger larger or adding a check valve right before the 2k tank.

Also, does it work without the bladder in the setup? (Just pump it straight up and then fire 1 shot). It seems like timing in the various phases of the trigger (tank valve, turret rotation, trigger valve) would be a bitch to synchronize.

Actually, if you swapped the 2k tank out for a backpressure tank, you could skip one of the timing parts entirely, and also not worry about air leak. The existing design hooked up to a bpr tank would work both to close the connection from the bladder and vent air for the dump valve in the air tank. Then you'd just have to synronize with trigger pull, but that's trivial since with only 2 pieces, and a the valve being able to be designed however you want, just make the valve close/vent at the very end of trigger pull.

[TantumBull]

If you were going with a back pressure tank, at that point you could really just use a directional control valve, though I suppose this would be a cheaper set-up.

[JATDO]

Very Very cool. I would love to see this gun when it is finished. Great idea even if it doesn't work. You could try and make your own PVC tank to keep the pressure up. And the firefly has enough dead space in the shell to fit it.

[Blasphemy]

Hell yes! *Dusts off Firefly and Hornet parts and cobbles them together.* Very good, I'm looking forward to this mod's completion because I have most of the parts sitting around out of use and all my ideas as to what to do with them were either way to ambitious or a total waste.

Now I just need to find something to use in place of the Magstrike bladder. Any suggestions?

[cheesypiza001]

Okay I just got it to work.

I pumped it 4 times and I got off 5 shots. However, only the first 3 shots seemed to be powerful. In addition, it was extremely difficult to pull the trigger for the first shot. I will be able to get more accurate information once I brace down everything instead of just using hotglue. If I pump it anymore than 4 times, the hornet trigger system shoots backwards due to the force of the rod pushing outwards.

Here's a picture of my current setup:





Once again, feel free to post with any questions, comments, or suggestions.

Edited by cheesypiza001, 16 November 2009 - 09:53 PM.

[OnyxZenith]

Damnit, you beat me to it, I was going to do this same idead with magstrike internals and put it in the deadspace of the furyfire! >

[cheesypiza001]

This whole thing is really starting to piss me off right about now. The trigger (the actual firefly trigger) just got really messed up and suddenly, everything (about 5 different things) is starting to sprout a leak. Like I said, this is really frustrating me, so I think I will come back to this in a few days.

[Hipponater]

This whole thing is really starting to piss me off right about now. The trigger (the actual firefly trigger) just got really messed up and suddenly, everything (about 5 different things) is starting to sprout a leak. Like I said, this is really frustrating me, so I think I will come back to this in a few days.

Is there goop on all the tubing to seal it? That alone can make a big difference in leaks. As for the firefly trigger, I'd replace some of the hot with epoxy or epoxy putty, especially the hot glue holding the part that pulls the AT3K tank pin.

Furthermore, I would band the bladder to squeeze it to higher pressures. Higher pressure will really help the air tank retain its power. As a side note, and out of curiosity, does anyone know what pressure air tanks typically use? Just PM me the answer if you know, not to clog up Cheesy's thread.

Also, JSB's idea would be good, though I can't visualize it now. Not having to work against the pressure would really help the trigger.

I'm really interested to see how this pans out, very nice.

[cheesypiza001]

This whole thing is really starting to piss me off right about now. The trigger (the actual firefly trigger) just got really messed up and suddenly, everything (about 5 different things) is starting to sprout a leak. Like I said, this is really frustrating me, so I think I will come back to this in a few days.

Is there goop on all the tubing to seal it? That alone can make a big difference in leaks. As for the firefly trigger, I'd replace some of the hot with epoxy or epoxy putty, especially the hot glue holding the part that pulls the AT3K tank pin.

Furthermore, I would band the bladder to squeeze it to higher pressures. Higher pressure will really help the air tank retain its power. As a side note, and out of curiosity, does anyone know what pressure air tanks typically use? Just PM me the answer if you know, not to clog up Cheesy's thread.

Also, JSB's idea would be good, though I can't visualize it now. Not having to work against the pressure would really help the trigger.

I'm really interested to see how this pans out, very nice.

Actually, please post the bladder pressure here as well. Thanks. I know where to leaks are coming from and they are all easily fixable. One is coming from the tank. I accidentally cracked part of the tank when I used pliers to rip off the plastic stabilizer that holds the tank to the screws. Another is coming from the hornet trigger moving (also fixable. The others, I already fixed. Banding the bladder and using epoxy putty would definitely help, but I was first going to see if it worked (proof of concept), then make it permanent. I guess I might as well make it permanent, otherwise I won't be able to see if it works or not.

[Galaxy613]

Good job so far, it's great to see someone trying to make a mod instead of speculating about a mod. If this turns out to be a failure it's something we can all learn from, but I hope it is successful.

Damnit, you beat me to it, I was going to do this same idead with magstrike internals and put it in the deadspace of the furyfire! >

Nothing is stopping you to completing it. In fact please do, because I'm interested in how you do it.

[TantumBull]

You really should be doing what bob suggested if you want to put less stress on the parts, and then you could still get away with hot glue.

[cheesypiza001]

You really should be doing what bob suggested if you want to put less stress on the parts, and then you could still get away with hot glue.

Okay, I will. I'm also gonna use epoxy putty due to the fact that I have a spare Firefly shell.

Edited by cheesypiza001, 17 November 2009 - 03:02 PM.

[southpaw]

Awesome! It's great to see something I did 4.5 years ago has found itself reincarnated (sorta) with you. Your version seems to be a much better design than my ghetto original.

I had a hard time with the "isolation" valve because at higher pressure, it was harder to seal and pull backward. The trigger needed alot of forward pressure to work. Too much actually, and instead of using enough rubber bands, I actually had to give the trigger a little forward nudge with my finger in order for it to work.

And I guess I had the "true" semi-auto down as far as the valves worked, but I still had to manually rotate the 2K turret. I see you've got an actual semi going on.

So yeah, in a nutshell, great job! Hope everything ends up working for ya.