14 replies to this topic

[Aeromech]

So I have received more than a few requests to explain how my reverse wye hopper works, and yes, it does work.


This is a Drev Bullpup with a reverse wye chopper, and one that started the inquisition. I'm using a chopper because I wanted to keep this as compact as possible, but a hopper without the 45 degree coupler would actually work better, because you don't have to change position to load a new dart into the chamber.


This image, posted by Gears was the one that actually inspired the above blaster, a bullpup with a horizontal top feeding magazine. It keeps everything compact and I wanted to give it a shot.


Here's the full assembly. Darts are loaded with the heads facing upwards. When the blaster is primed, the suction from the skirt seal actually pulls the dart backwards into the stub; the screw in the stub prevents the dart from being sucked into the air supply source. The dart is now seated and the head should have fallen away from the clip. The dart is now in line with the barrel. When the blaster is fired, the dart is forced out through the barrel.


And here's the detail view.
(1) Marks the area that needs to be filed down with a rat tail file, just get it in there and start removing material. It will feel new and strange at first, but you'll learn to enjoy it.
(2) Denotes the part of the stub that must be chamfered smooth. Just like the barrel, a bevel is necessary to allow the darts to feed smoothly backwards into the stub. Just do this like you would do it on the barrel throat.
(3) The screw that prevents the darts from being sucking into the air supply chamber

Notes
This has not been war tested, but it seems to work pretty well. Keep in mind my darts are slightly shorter than the standard, I usually rock about 1-1/8 inch long darts. Don't ask me how I arrived at that figure. If your darts are longer than that, just adjust the distance of the screw from the throat of the stub until you get reliable feeding. This sort of solves a problem that doesn't exist, but I hope it may be useful to some of y'all out there.


She likes showing off.

Edited by Aeromech, 07 January 2015 - 06:16 PM.

[Tobias]

Genius! How well does it feed compared to a normal hopper?

[ShadowKing]

Great job Aeromech. Does this work with just suction feeding? Does it work only with pumps and things like that or can it be used with air powered blasters?

[rockinon96]

Great job Aeromech. Does this work with just suction feeding? Does it work only with pumps and things like that or can it be used with air powered blasters?

I believe the original intent of this hopper was for it to be only for springers, because the dart has to be sucked up to the dart stopper to fire, air powered blasters can't achieve this function.

And Aeromech, I congratulate you on this thread. you beat me to it.

Edited by rockinon96, 07 January 2015 - 09:18 AM.

[Aeromech]

Great job Aeromech. Does this work with just suction feeding? Does it work only with pumps and things like that or can it be used with air powered blasters?

I believe the original intent of this hopper was for it to be only for springers, because the dart has to be sucked up to the dart stopper to fire, air powered blasters can't achieve this function.

What he said. I don't even own an airgun these days, I am pretty much exclusive to springers. It has never been tested on an airgun so I cannot say for certain if it does work or not. Because it points forwards, it looks vicious on a rainbow pump or something, and it works well if you're using my removable clips. To push in a clip on a standard wye, you have to push forward, which may loosen the connection somewhere between the wye and the blaster bushing (I typically don't use adhesives to secure this connection). Using removable clips with the reverse wye, you have to push the clips in backwards, which in turn secures the wye into place if it has come loose.

[Langley]

Is (1) in that image (the part that needs to be filed off) exclusive to McMaster wyes? I have mostly flexPVC wyes and they don't seem to stick out like that on the inside of the acute side of the wye.

I would love to see some kind of magnetic sweeper on the back linked to the pump handle that helps pull darts down the wye and then forward against the barrel. You must be loosing at least some efficiency to having the dart farther back in the wye than on a normal hopper, with some air being lost to just pushing the dart forward and sealing it against the back of the barrel.

[rockinon96]

What he said. I don't even own an airgun these days, I am pretty much exclusive to springers. It has never been tested on an airgun so I cannot say for certain if it does work or not. Because it points forwards, it looks vicious on a rainbow pump or something, and it works well if you're using my removable clips. To push in a clip on a standard wye, you have to push forward, which may loosen the connection somewhere between the wye and the blaster bushing (I typically don't use adhesives to secure this connection). Using removable clips with the reverse wye, you have to push the clips in backwards, which in turn secures the wye into place if it has come loose.

When I was thinking about this, I knew some drawbacks were that it would be ONLY for springers, because you would need vacuum seal to bring it back, and fire it afterwards, and with air system blasters, there is no way for a vacuum. It would result in pushing all the darts back up the hopper. So, aeromech, no it would not work in an air system blaster.

[Drev]

Wow, that hopper looks good. I guess I just discovered a new thing to make this weekend. I assume you don't mind if I link to this in the writeup, right?

As for the blaster itself, I really like how the slots go all the way to the front. I think I will be doing that on my next bullpup. Also, did you make this be able to slam fire by any chance?

[Aeromech]

Is (1) in that image (the part that needs to be filed off) exclusive to McMaster wyes? I have mostly flexPVC wyes and they don't seem to stick out like that on the inside of the acute side of the wye.

I would love to see some kind of magnetic sweeper on the back linked to the pump handle that helps pull darts down the wye and then forward against the barrel. You must be loosing at least some efficiency to having the dart farther back in the wye than on a normal hopper, with some air being lost to just pushing the dart forward and sealing it against the back of the barrel.

Whoops, that part you're referring to was actually an artifact of the CAD drawing I forgot to remove. The photo has been updated. Basically, just file off the inside of the 45 degree bend to allow the darts to drop more freely. As for the loss in efficiency, Yes I'm sure I am losing something, but the blaster still shoots rather hard. I put this hopper on another blaster and it firs as hard as a standard RBP, though I will not have quantitative data until I can use a chrony.

Wow, that hopper looks good. I guess I just discovered a new thing to make this weekend. I assume you don't mind if I link to this in the writeup, right?

As for the blaster itself, I really like how the slots go all the way to the front. I think I will be doing that on my next bullpup. Also, did you make this be able to slam fire by any chance?

I come from a mechanical engineering/manufacturing background, so if I can make the production of the blaster easier, that's a huge plus. Having the slots extend all the way forward accomplished two things: It allows the use of a plain old woodsaw to be used in the production of the slots, and a long, straight saw produces long, straight lines without the use of heavy machines or the production of fumes and dust like a dremel would. It also allows for the fastest field strip you can think of. The slots are capped by a cutting board disc, held in place only by two screws. So field stripping this blaster takes only about 30 seconds and a screwdriver. I had to perform several hours of troubleshooting on this blaster, and this disassembly method allowed me to go in and check out the insides of my blaster without taking apart the pump or ruining the air seal in the back. Seriously, Two screws are the only thing that hold the guts of this blaster in. I would recommend this method of capped off slots to basically everyone, and I have been doing so since I started building.

This one can't slamfire, but it doesn't really lend itself to doing so because of the long length of pull, and the long distance between the pump and the stock. I honestly wouldn't do it, the catch is already really thin and I wouldn't want to make a sloped slamfire catch a la makeitgo with so little material to work with. Yeah, totally link it if you need to use it that's kind of why it's here.

Edited by Aeromech, 07 January 2015 - 06:28 PM.

[shmmee]

That's gotta be the coolest innovation I've seen in ages! I'm wondering how much of an impact the second dart has upon the seated and ready to fire dart. I'd imagine if the second dart is sitting on the loaded dart at that 45 degree angle, there's a chance that it might fall enough to lock the loaded dart in place and that upon firing the loaded dart would first have to force it's way past the second dart - wasting energy while doing so. Do the darts in the feed tube jump much or kick back when you fire? I'd imagine that to be a symptom of secondary darts jamming primary darts.

[Drev]

I come from a mechanical engineering/manufacturing background, so if I can make the production of the blaster easier, that's a huge plus. Having the slots extend all the way forward accomplished two things: It allows the use of a plain old woodsaw to be used in the production of the slots, and a long, straight saw produces long, straight lines without the use of heavy machines or the production of fumes and dust like a dremel would. It also allows for the fastest field strip you can think of. The slots are capped by a cutting board disc, held in place only by two screws. So field stripping this blaster takes only about 30 seconds and a screwdriver. I had to perform several hours of troubleshooting on this blaster, and this disassembly method allowed me to go in and check out the insides of my blaster without taking apart the pump or ruining the air seal in the back. Seriously, Two screws are the only thing that hold the guts of this blaster in. I would recommend this method of capped off slots to basically everyone, and I have been doing so since I started building.

This one can't slamfire, but it doesn't really lend itself to doing so because of the long length of pull, and the long distance between the pump and the stock. I honestly wouldn't do it, the catch is already really thin and I wouldn't want to make a sloped slamfire catch a la makeitgo with so little material to work with. Yeah, totally link it if you need to use it that's kind of why it's here.

Two screws is what hold my blaster together too. Just don't use duct tape when testing, because that tends to break large TV's. I'll go ahead and link this.

[Number 1 nerf nut]

NOOB WARNING I would think that you could use this on a HAMP right, because of the suction caused by pulling the pump foward

[KaneTheMediocre]

NOOB WARNING I would think that you could use this on a HAMP right, because of the suction caused by pulling the pump foward

I've done it, but I had to put a flap over the barrel to act as a check valve. I made it with paper and tape. It didn't seem to interfere with the dart coming out, but I never got the reverse wye working flawlessly. Maybe 90%, it would just get stuck sometimes and take a few cycles to get going again.

[Number 1 nerf nut]

Ok thanks

[Maniacal Coyote]

I've done it, but I had to put a flap over the barrel to act as a check valve. I made it with paper and tape. It didn't seem to interfere with the dart coming out, but I never got the reverse wye working flawlessly. Maybe 90%, it would just get stuck sometimes and take a few cycles to get going again.

Thank you for letting me know this before I begin building the project I have in mind.

BTW, for your/MHA's HAMP design, would using a 2" coupler, 2"to3/4" bushing, and a sealed length of 3/4" instead of the 2" end cap cause any foreseeable problems?

USER WAS SUSPENDED FOR THIS POST

Edited by Langley, 21 April 2015 - 09:30 PM.
Necro'd a 4 month old thread to ask someone who happened to reply a totally off-topic question.