17 replies to this topic

[Boot]

Again, skip this bit if you don't mind the details of the project, and only want to see the completed blaster.

After being a bit disappointed with the speed that the Eccentric dropped off the page I am hoping that this will generate more interest. Being the last in my 7 original projects I think it is the most innovative and practical of them all.

Often people have tried to create a semi-automatic blaster that still achieves reasonable ranges, most notably in the case of cheesypiza001 who completed a design similar, but significantly more complicated than this one, and to my knowledge never completed a practical blaster off the concept. Major props to him because it was after reading his posts that this idea formed in my head.

Interestingly, like the Eccentric this build was originally going to be put into a maverick for feeding. After the failure of the Eccentric however I decided to save myself the trouble and go with an RSCB.

This is the continuation of the Mirage series, and although it started out as just a proof of concept, this design proved so effective that even the prototype is a VERY practical and respectable blaster. I will be applying the same pneumatic setup to a more efficient loading system and a nicer shell in the final iteration of the Mirage which I am working on now!

For those of you wondering about the name, Mirage is just the series, and SS stands for small and simple.


Start here!


After some trial and error, and a lot of waiting for materials I came up with this:



Again, its ugly but I am incredibly excited about this concept.

Three components make up the propulsion setup.

-A Magstrike pump and bladder
-A modified hornet sliding valve (NOT the blast valve)
-A Big salvo tank (any back pressure tank will work, but this was chosen because it has a good amount of volume. Enough for greater than 100' ranges, but not so much that it is ridiculous to prime)

The operation is based off of the properties of a back pressure tank. If you know about how these work skip the next paragraph, if not read on.

A back pressure tank like the one in a Drain blaster, big salvo and hornet are triggered by changes in pressure. When they are pressurized, and you let some air out of the back the lower air pressure in the back of the tank pulls the valve backwards, releasing the rest of the air out the front firing the dart.

Normally these tanks are pressurized with a pump, released, and then pressurized again. In this case all of this is done beforehand and stored in the Magstrike bladder (the green sock in the image. The sock is just to protect the bladder from the sun).



The pressurized air then equalizes the pressure in the bladder, and in the BS tank when the trigger is at rest:



When the trigger is pulled, and the plunger in the valve slides past the port connected to the BS tank pressure is released and the tank fires:



As the trigger is held down, it DOES NOT slide past the port which the bladder is connected to and so no air is lost other than that from the BS tank. Pressure from the bladder then pushes the plunger back to its original position and the process repeats. No return spring is needed, and this way when the pressure is too low the trigger stays compressed acting as an indicator for pressure levels. This way true semi auto is achieved. The bladder is fully pumped, and then a burst of air is released (equivalent to a normal BS firing) with each squeeze of the trigger.

The valve itself is the only modified component in the whole blaster. I simply cut it shorter and attached it to the trigger. I connected the last two connection ports. The first to the BS tank, the second to the Bladder and pump. Also, because there is actually a check valve in this valve, there was no need to plug the back of the valve (where the unconnected tubing sticks out):






The rest of the build is purely about quickly putting together a test rig. A 12" RSCB constructed exactly like that on the Eccentric:



This RSCB was actually developed for this build, and used on the Eccentric first. I needed an RSCB fast and efficient enough to complement the Semi automatic capabilities of this setup. See the Eccentric post for details on construction. Even the style of construction is the same. The tank is glued directly into the RSCB vertically, and the handle is Zip tied on. The trigger is equally simple. A hole drilled (by hand ) through the handle with a hex wrench going through it acts as a guide for the valve's sliding motion. The PVC scrap is just for comfort.



The result surprised me a lot. Despite the sub-optimal barrel length the first shot clear 80 feet while the last goes about 70 (on average. Level with streamlines) and the ROF is incredible. I won't even try to put a value on it, but even with an RSCB its fast (Although the RSCB was just for testing purposes. The final Mirage will use a breech new feeding system I am developing).

The biggest surprise however was that with a full fill of the MS bladder at 20 pumps I can fire the blaster 6 times at full force. At just 15 pumps I can empty the RSCB (with 4 streamlines in it). (this goes to show just how inefficient the MS valve actually is)

It is also small and maneuverable!

Next to a BBB:



And more:





Of course I'll let you see all of this for yourselves:

Videos!

Firing test

Overview of blaster

Humble beginnings (The very first valve test)

Feel free to ask any questions as this may be a bit confusing. Again, comment on the clarity of the writeup because there always will be more to come.

As far as I can tell this is the first semi automatic setup that is this simple and effective and I am surprised that no one has done it (or documented it) before. If anyone has and I have missed it major props to you!

Edited by Boot, 02 December 2010 - 05:29 AM.

[NerfGeek416]

If you use one of the blast valves from the side of a hornet, it might work better. When fooling around with my hornet, I noticed that the blast valves from the side release air only when they are halfway depressed. This means that mashing on it and holding it will still only release air for a moment. This saves pressure. If this is common knowledge, I apologize.

Anyway, great job. I don't know why people don't like back pressure tanks, since they are so versatile and easy to place anywhere you want on a blaster.

Regarding the clip, have you considered a hopper? They combine the simplicity of a RSCB with the semi-auto of a breech

[shmmee]

I'm always impressed with what you're able to pull off with the materials you have available in china. I'm begining to become a fan of your work. From the shape of the thing it looks like it might fit reasonably well inside a firefly shell (with the bs tanks sticking out the side instead of down, and the bladder replacing the turret) should you ever choose to abandon your minimalist ways


Interesting move switching from the MS to a backfire tank, though i was hoping for more information as to how and where you expanded the MS piston in the first incarnation. (i'm hoping to do the same thing to my rf 20 which is similar in function.). I'm looking forward to seeing the final version of this project.

Edited by shmmee, 03 December 2010 - 11:02 PM.

[LT DAN ICE CREAM]

Another great writeup, man! Given the materials you have access to, these are impressive blasters.

In this blasters current state, it looks like you'd be able to fit it very well inside of a Magstrike shell. I might have to give this one a try; I've got everything but a viable back pressure tank.

[shmmee]

In this blasters current state, it looks like you'd be able to fit it very well inside of a Magstrike shell. I might have to give this one a try; I've got everything but a viable back pressure tank.

Crap! that does look like it would fit perfectly in a mag strike shell. The tank should sit well in the clip slot, and it's allready fitted to a pump and bladder. Firefly. Really? What was i thinking! I'm going to have to try that with an expanded hornet tank durring Christmas break! Now i'm really excited for this mod.

[snakerbot]

Dammit, Boot! You just had to go and post this before I could finish mine. I've an almost identical valve system set up in a DTB, but it's not quite right yet.

In all seriousness, nice work. I like your trigger setup. Mine has a ton of friction, requiring a two-finger trigger to actuate, and it still leaks.

Also, NerfGeek, if your blast buttons stop releasing air when they are all the way depressed, then there is something wrong with them. They should just open and stay open.

[Hipponater]

Also, NerfGeek, if your blast buttons stop releasing air when they are all the way depressed, then there is something wrong with them. They should just open and stay open.

If you aren't putting anything on the button (tack, spacer), when you push it directly with your thumb, you can block the air by pushing it all the way down. It's open, but the air can't be released because your thumb creates a seal.

Interesting work, I like how the air pressure pushes the rod back into place

[Split]

This thing is excitingly small as it is; I say don't shell it. I would love to run around with like 6 of these that have a pump connection (one pump that disconnects and reconnects to all of them). Pump em all up, run around dual wielding em and just drop and grab the next as needed. Tiny sceptor-like guns. You're getting pretty impressive ranges for streamlines in an rscb from just a big salvo tank though.

The system is just like this one though, or any QEV/Backpressure tank with a three way valve. The big trick has always been the reloading, which really wasn't solved all that well until the hopper came out this summer.

Edited by Split, 02 December 2010 - 04:26 PM.

[NerfGeek416]

The buttons are not being covered by my finger. There is a definite "sweet spot" where the air keeps releasing. They worked just fine with my hornet, until the trigger snapped.


EDIT:
Just checked with a screwdriver, my finger was sealing the release. Hipponater and snakerbot were correct.

Edited by NerfGeek416, 02 December 2010 - 08:12 PM.

[Green Wing]

Very nice work. I love how it is so simple yet so effective. I will definately be making some of these as soon as I get some Big Salvo tanks.

Edited by Green Wing, 27 October 2012 - 10:40 PM.

[SonReeceSonJensen]

That is just tits. Sorry, nothing constructive to add: only compliments today.

[nisaburo]

Nerfgeek, Boot says that he uses the hornet plunger valve because it only vents the air from the BS tank. If he used a regular blast button in conjunction with the magstrike bladder then it would fire the BS tank but also lose a lot of air from the bladder.

Boot, this is stupidly simple and I love it. Before I actually read the writeup I thought it was just another dumb RSCB'ed tank and bladder set up being dubbed "semi-auto." This can actually easily be made semi auto. Fantastic work!

[Boot]

Sorry for the lack of replies, I've been busy at school and have only just checked back on this thread. Its very nice to see the interest this is generating because I think the valve setup is the most viable semiautomatic setup I have seen (in terms of a good balance between ROF and range).

If you use one of the blast valves from the side of a hornet, it might work better.

Anyway, great job. I don't know why people don't like back pressure tanks, since they are so versatile and easy to place anywhere you want on a blaster.

Regarding the clip, have you considered a hopper? They combine the simplicity of a RSCB with the semi-auto of a breech

Thanks. As "nisaburo" said, the point of the plunger valve is so that it only can possibly vent air from the BS tank. I get what you mean with the blast valve, but in that case you would have to pull the valve at a certain speed each time (releasing enough air for a perfect release, but not enough to waste the pressure in the bladder). Also, in the case of the plunger valve there is no path for pressure to be released directly from the bladder, while when using the blast valve pressure would escape from both the BS tank and bladder at the same time.

If it is cost of the valves that worries you fear not. The next "Mirage" will use a valve that is ridiculously cheap and easy to build (and from what I've seen with the prototype, even more efficient).

In the case of the clip, I believe it was "Kane the mediocre" that said hoppers don't work well on Air guns, and from what I understand with the workings that seems to be the case. A springer has a slow air release, and so a bit of it goes into "bending" and aligning the dart in the barrel while the rest propels it. Because an air gun releases its pressure very quickly however, most of that escapes around the dart before it is aligned making for a very weak shot. (I also can't find a source for wyes in Beijing, and so try to use other methods).

The main idea with the breech is that I am trying to create a semi automatic setup that has zero dead-space in front of the tank, meaning that it will get the standard 100 foot ranges of the BS while still maintaining a very high ROF.

Just because I can't get hoppers though doesn't mean you shouldn't try it out! For all i know it may be the best way to make this.

Boot, this is stupidly simple and I love it. Before I actually read the writeup I thought it was just another dumb RSCB'ed tank and bladder set up being dubbed "semi-auto." This can actually easily be made semi auto. Fantastic work!

Thanks! I am quite surprised that this hasn't been done before since all you need to make a test rig is in the hornet! Also, thanks for the explanation about the workings of the valve, I couldn't think of the right way to put it in the writeup.

I'm always impressed with what you're able to pull off with the materials you have available in china. I'm begining to become a fan of your work. From the shape of the thing it looks like it might fit reasonably well inside a firefly shell... should you ever choose to abandon your minimalist ways

I was hoping for more information as to how and where you expanded the MS piston in the first incarnation.

The main goal in this project was to get a high ROF blaster with equally high ranges. I figured it was easier to slightly lower the ROF rather than mess with a low capacity tank (although after this project I may revisit the idea). The tank expansion itself is easy, and a few people have done it in the past. Just like any other tank expansion, you drill a hole and then add a sort of secondary tank (I believe TantumBull made a homemade of sorts based of the MS valve which has a very nice and clean tank expansion). Good luck on you're RF20 project! It's funny because I just bought a RF20 (because their easier to get here) for the final "Mirage". The larger bladder and pump increase efficiency and capacity.

Also, with these test rigs I always go for minimalist. Although I don't really like putting things in other shells (unless they have a sort of ridiculous "Tiny tim" value), I can guarantee that the Mirage 2.0 will look better, and will have a homemade shell of sorts.

Another great writeup, man! Given the materials you have access to, these are impressive blasters.

In this blasters current state, it looks like you'd be able to fit it very well inside of a Magstrike shell. I might have to give this one a try; I've got everything but a viable back pressure tank.

Thanks! A few people are commenting on the materials in China, but I actually don't think it's that bad. Although there is no McMaster, the materials here are simply a different set of materials. I think as the hobby (hopefully) grows building material will be much easier to find. The main thing is that I am starting more or less from scratch, and so don't know what size of material x fits material y.

See above about the MS shell. Although I can kind of see something where the trigger pull moves the clip up, solving the feeding problem... OOH!

Dammit, Boot! You just had to go and post this before I could finish mine. I've an almost identical valve system set up in a DTB, but it's not quite right yet.

In all seriousness, nice work. I like your trigger setup. Mine has a ton of friction, requiring a two-finger trigger to actuate, and it still leaks.

Ouch, sorry. Although I do suggest using a different feeding setup. At least from my experience when trying to put this in a maverick even once you get it to work ranges won't be as nice as they could be. If it's any consolation this was done during the summer, about 4 months ago. About you're valve though, what are you using? Where is the friction coming from? The hornet valve is actually designed for this so it moves and seals perfectly.

Anyways, good luck on you're project. Hope to see it soon!

Interesting work, I like how the air pressure pushes the rod back into place

Thanks, this was actually a mildly unintentional part of the build. I had underestimated the strength of the pressure in the setup, and so originally had a return spring, but when it broke off I realized there was absolutely no need for it.

This thing is excitingly small as it is; I say don't shell it. I would love to run around with like 6 of these, run around dual wielding em and just drop and grab the next as needed.

You're getting pretty impressive ranges for streamlines in an rscb from just a big salvo tank though.

The big trick has always been the reloading, which really wasn't solved all that well until the hopper came out this summer.

You make me want to build a second one and wield these akimbo... and yes, as you may have noticed from my other builds size is always one of my first concerns. Even in my earlier builds like the PA crossbow I have always tried to shrink things down as much as possible. Because this is just a prototype I won't be shelling it, but the final Mirage will have a home built (hopefully transparent if I can get the materials) shell.

About the ranges, I was actually wrong about the length of the RSCB. it holds 4 streamlines, but in a 3+1 configuration where one is in the barrel (making for a 9" RSCB as opposed to a 12" one). Also, streamlines have a tendency of "Floating" a bit from this blaster. With my reasonable CDTS the ranges are more like 75 feet. If the ranges don't seem like enough for people though, banding the bladder with this setup make's an ENORMOUS difference. In the normal MS banding the bladder only really increases ROF because the spring in the oscillating valve stays at the same strength. In this case though, higher pressure in the bladder results in higher pressure in the whole system. Although you sacrifice the number of shots per fill slightly, ranges go up by a lot.

Anyways thanks for the comment. I actually never noticed that 3 way valved had previously been used before.

In terms of feeding, I am hoping the breech setup I am making will work, but we will see. If it doesn't I'll probably experiment with hoppers and spring loaded RSCB's.

Very nice work. I love how it is so simple yet so effective. I will definatly be making some of these as soon as I get some Big Salvo tanks.

Thanks. If you aren't too pushed for time however, the next mirage should be much more effective (although it will be a while before it's released since I don't know when I'll find time to make it). If you do attempt this specific build then keep in mind you need a really smoothly working RSCB, and that banding the bladder makes a huge difference.

That is just tits. Sorry, nothing constructive to add: only compliments today.

Thanks, it's ok, compliments are always appreciated

_________

Thanks for the comments everybody, if anyone has any questions (or compliments ) please post!

Edited by Boot, 04 December 2010 - 09:17 PM.

[snakerbot]

Ouch, sorry. Although I do suggest using a different feeding setup. At least from my experience when trying to put this in a maverick even once you get it to work ranges won't be as nice as they could be. If it's any consolation this was done during the summer, about 4 months ago. About you're valve though, what are you using? Where is the friction coming from? The hornet valve is actually designed for this so it moves and seals perfectly.

Anyways, good luck on you're project. Hope to see it soon!

The reason I made it in the first place is because I had a DTB that wasn't firing, so I wanted to do something with it. Couple that with a bunch of hornet parts that weren't doing any good sitting in my parts box, and this happens.

And the valve I'm using is actually a hornet valve. I guess the air just leaks around the o-rings in it or something, but it's always leaked, even when it was still in the hornet. I tried replacing the o-rings, but couldn't find any that fit properly.

Finally, I wouldn't get your hopes up for seeing mine any time soon. With finals coming up I won't be able to work on it much, and then I'm going home for winter break, so it'll be a good two months or so.

[Zorns Lemma]

I like it.

The trigger seems like an easier-to-make but harder-to-replace (need to gut another hornet, not like those things are worth anything lol) version of either Atomatron or Cheezypizza's pilot valves but the fact that you still managed it means you have an excellent understanding of how these complicated (relative to spring-powered pneumatic plungers) air storage and redirection systems work.

Keep up the good work and go invent a cheap and easily reproducible homemade qev tanks and pilot valves! (/joke)

[Draconis]

The triple strike and Big Salvo triggers operate in a similar fashion to this, and if positioned correctly can be modified to accept a constant air source while maintaining semi-auto fire. I've done it with both using an external tank.

[NerfGeek416]

Would it be possible to chop up the semi auto valve so that the input was the same as how it is normally set up, and the output is the closest hole to the back? This would simplify the design. I will be building something like this over the weekend.

You could even use the remaining portion of the valve to make something like the original design.
This would make it possible to build 3 single-shot guns and 2 semi-autos out of a single hornet. Hasbro really screwed up the design.

[Boot]

Would it be possible to chop up the semi auto valve so that the input was the same as how it is normally set up, and the output is the closest hole to the back? This would simplify the design. I will be building something like this over the weekend.

It is entirely possible, and how I originally wanted to set this up, but for some reason the check valve in the back would not allow air through. I think I may have jammed it during testing. My next valve setup won't have this problem though, since it will be made of ridiculously cheap materials (hopefully it will be up sometime in february). A hornet valve is not actually necessary. All you need is a plunger that slides airtight within a tube with a few holes drilled in it. Theoretically you could actually build this valve out of a pump (The SSB pump comes to mind).

I didn't think of making TWO valves from a single hornet valve though. That is pure genius. Too bad I actually threw away the first section I cut off .

Also, that is a good point about the Hornet. I personally love the blaster just because Tiny tim, Scrappy, and this blaster were all made from a single hornet (and I still have an extra tank left over!).