39 replies to this topic

[Ryan201821]

I present the RainbowPup, no it's not a typo.



Loosly based off of Kane's concept

Pump action, bullpup, spring powered, Rainbow. Only about 28" long from front to back of the stock, including barrel.



The blaster is primed by a section of 1" PVC linked to the 2" polycarbonate pump grip pushing on a series of telescoping tubes connected to the front of the plunger rod. If I had access to Kane's lathe when I made that part, I probably would have done that instead. The only problem with this is the bolt sticking out of the pump grip. A vertical grip would solve this, but I'd also like the option of a regular pump grip. Any suggestion here would be welcome.



Standard plunger head, with omni-directional plunger rod as seen in the RBP Rev 2. The seal sits in front of where the CPVC elbow is, which is 1 1/2" x 1/2" polyethylene lathed to fit inside 1 1/4" PVC. Can't really see it in the picture, but it's there. Another not so great part of the design is the elbow has to be hot glued into place so it can seal. I'd also like to change this part somehow.



Here is the blaster primed. The handle is made from LDPE, just made it by hand. If you're looking for the plunger head, it's basically inside the tee, right at the end of the PVC.



Another shot



Compared to a standard RBP. Way shorter.

Overall, I like how it turned out, even though I need to fix a couple things to streamline the design. For those that will ask, it has 6 1/4" of draw (actually wanted 6" but measured wrong somewhere along the way), and shoots as far as any other homemade I've built (range testing is silly).

Questions, comments, and suggestions are welcome.

Update:

Here's basically what the finalized version will look like.

Edited by Ryan201821, 12 June 2012 - 04:50 AM.

[Keo]

I absolutely love it.

Are you selling them by chance ?

[Ryan201821]

I absolutely love it.

Are you selling them by chance ?

Not currently, but yes definitely.

[HasreadCoC]

Would you be able to easily replace the tape in the design with something more...... sturdy looking? Not that I doubt it'll hold, but if it could be replaced by a screw or two functionally, I think it would look stronger/more heavy-duty, if you know what I mean. Just a more refined look overall I guess.

Anyway, this looks like fantastic design/adaption overall, I hope to see some of these at wars soon.

[mak]

Could you thread the elbow and than pit goop on it than screw it in? Keep in mind this is just a thought


Sorry, I wrote this right when I woke up......

Edited by mak, 07 June 2012 - 04:59 PM.

[Ryan201821]

Would you be able to easily replace the tape in the design with something more...... sturdy looking? Not that I doubt it'll hold, but if it could be replaced by a screw or two functionally, I think it would look stronger/more heavy-duty, if you know what I mean. Just a more refined look overall I guess.

The current way the elbow is attached, no. There's nothing I can screw to, or into, or through. Tape is just a better option for that at the moment. Now if that entire part was different, then I could and would. Believe me, I use a screw over tape every time I can.

Could you thread the elbow and than pit goop on it than screw it in? Keep in mind this is just a thought.

Maybe. I would need to buy a $30 die, $10 tap, and I'm not sure if there would be enough length for the threads to work well at all.

[snakerbot]

Kane said his polyethylene seal was less than perfect. Is yours better because of the different plunger rod material or is it still bad? Are you considering using some sort of ring seal? Maybe 9691k53 or 9691k54 could work.

[mak]

Maybe. I would need to buy a $30 die, $10 tap, and I'm not sure if there would be enough length for the threads to work well at all.
[/quote]


Could you use Kanes lathe and make it like they make gun barrels?

[Collective]

To give the elbow something more substantial to screw into, why not extend that tube that connects the handle to the body of the blaster back an inch or two and screw through both that tube and the body itself?

[Ryan201821]

Kane said his polyethylene seal was less than perfect. Is yours better because of the different plunger rod material or is it still bad? Are you considering using some sort of ring seal? Maybe 9691k53 or 9691k54 could work.

Before I put the blaster together it sealed perfectly with the plunger rod in there. I'm not sure if I got lucky, or I machined it better, but it's working for me. The polyethylene tube I used to machine this comes undersized on the ID, but luckily I have a magic spade bit (no joke), that opens the hole up to the perfect size for the plunger rod. The ideal thing to do would use something like you suggested, or an o-ring but I'm not sure how I would keep it in place. This also might cause more friction than what is currently being used. What I would like to do, but can't at the moment would be to machine the same piece with a groove inside to hold the o-ring in place. I might tinker with this a bit, but for now I am not noticing it to cause any problems with performance.

Perfect seal is also really not necessary with any blaster. Many of my blaster don't get perfect seals and don't perform any differently than ones that do. There is however a fine margin to what is acceptable and what will cause a noticeable performance drop.

Could you use Kanes lathe and make it like they make gun barrels?

lolwut?

To give the elbow something more substantial to screw into, why not extend that tube that connects the handle to the body of the blaster back an inch or two and screw through both that tube and the body itself?

Is this running off the idea I should thread the elbow, or something completely different? I'm not sure I follow this, or see how it would help.

Edited by Ryan201821, 07 June 2012 - 01:43 AM.

[andtheherois]

I can't really tell what's going on in the plunger head pic, but does the Plunger head stop before hitting the elbow? Is the elbow just embedded into the PVC wall? before the bushing?

[Ryan201821]

I can't really tell what's going on in the plunger head pic, but does the Plunger head stop before hitting the elbow? Is the elbow just embedded into the PVC wall? before the bushing?

Of course! Who do you think I am?

The blaster has a string stop, seen in all of my blasters, so you can dry-fire it. The elbow has a piece of CPVC sticking out of it, which fits into a 5/8" hole in the top of the plunger tube. And yes, just before the bushing that seals the whole thing together.

[imaseoulman]

Beautiful work. Seeing this makes me happy I still lurk. I still hate homemades, but that is a beautiful piece of machinery.

[Ambience 327]

You really take an idea and run with it, don't you Ryan? I still find the idea of the crossbow-based blasters to be slightly more fun overall, but you can't argue with the compact nature of this design. I don't think I have ever seen anything that could hope to compete with this thing in terms of size+power combination while retaining the pump-action springer nature. I think this new bullpup style plunger system is the way forward in homemades - and it pretty much puts Hasbro's engineers to shame for the simplicity and effectiveness of the design.

[taerKitty]

http://www.mcmaster.com/#98002A980 + http://www.mcmaster.com/#98002A709 for the pump handle bolt?

+

That's in response to your ask for suggestions. As for the blaster itself, it's beautiful!

Edited by taerKitty, 07 June 2012 - 11:29 AM.

[Meaker VI]

I think this is an interesting and unique plunger setup, but the only thing that seems have changed as far as the length is concerned is the location of the barrel? So, rather than having a straight plunger force air into a barrel in-line (increasing the length of the blaster by the length of the barrel), you've put the barrel on top and avoided the tubing regularly required with your plunger setup.

This system could allow you to get more air volume if you put a plunger head on both ends (and left the front end of the plunger rod open so that air could flow through it into the main compression chamber), but I'm not sure if that would actually help at all - would that allow you to build it with a shorter draw, or would that just make the spring work slower?

This is a great looking blaster in any event.

Edited by Meaker VI, 07 June 2012 - 01:49 PM.

[Bchamp22795]

I decided to make Kane's Crossbow right after I saw it, and to seal the rainbow catch area I used a 1" to 1/2" bushing, cut off half of it (the half without the lip...the not 1/2" half), and then super glued a 1/2" ID rubber grommet that fit perfectly in there. Afterwards, all it took was hammering it to rest up against the rainbow catch. Afterwards I drilled the hole for the elbow, and continued from there.

It seems to seal just fine with some lube on the plunger rod. Just my two cents. Whatever is easier/more cost effective for you.

[mak]

Is this running off the idea I should thread the elbow, or something completely different? I'm not sure I follow this, or see how it would help.

Yes, I am getting at the idea you should thread the elbow.

[Crusher9051]

What are the ranges of this? How many pounds of draw back does it get?

[Daniel Beaver]

ooo, ooo, I can answer this!

What are the ranges of this?

Far

How many pounds of draw back does it get?

24 pounds

[Ryan201821]

I decided to make Kane's Crossbow right after I saw it, and to seal the rainbow catch area I used a 1" to 1/2" bushing, cut off half of it (the half without the lip...the not 1/2" half), and then super glued a 1/2" ID rubber grommet that fit perfectly in there. Afterwards, all it took was hammering it to rest up against the rainbow catch. Afterwards I drilled the hole for the elbow, and continued from there.

It seems to seal just fine with some lube on the plunger rod. Just my two cents. Whatever is easier/more cost effective for you.

So I actually just tried this on my newer one that I almost just finished building. It seems to seal okay, not amazing, but okay. I have to test it tomorrow to see how far its shooting in day light but it seems it should work well enough. If your plunger rod is something slightly larger in OD (Nylon), than it's possible it might seal better for you. Maybe my grommets are slightly different, I have no idea where I got them, just happened to be in my bin for my rubber stuff. Instead of super gluing it though I pinned it in there with a piece of 1/2" PVC in front of it. Maybe that's causing it to leak.

Anyway, I'll have more details tomorrow when I finish it up and see how well it shoots.

[Bchamp22795]

If your plunger rod is something slightly larger in OD (Nylon), than it's possible it might seal better for you

I'm using one solid piece of nylon rod, no cuts in it, with an eye bolt on the "front" end. The string threads through there and the catch catches on the face with the eye bolt attached. The nice thing about it is that you don't have to drill exactly center since the string that threads through the eye bolt stops it from rotating. You can always rotate the plunger rod so the larger catch area is up. If you want, I can take pictures...but I think the idea of the eye bolt is simple enough.

Also, I used silicone grease. The plunger rod slides without it, but I think it helps.

Edited by Bchamp22795, 10 June 2012 - 10:31 AM.

[Ryan201821]

I'm using one solid piece of nylon rod, no cuts in it, with an eye bolt on the "front" end. The string threads through there and the catch catches on the face with the eye bolt attached. The nice thing about it is that you don't have to drill exactly center since the string that threads through the eye bolt stops it from rotating. You can always rotate the plunger rod so the larger catch area is up. If you want, I can take pictures...but I think the idea of the eye bolt is simple enough.

Also, I used silicone grease. The plunger rod slides without it, but I think it helps.

I ended up getting this to work anyway. I ended up smashing the PVC holding it in there just a bit harder to compress the grommet. Now it seals perfectly. I finished the blaster, but it sucks.

I'm guessing I have too much deadspace. I might try filling it with something, but I'll probably go back to the elbow.







My deadspace dilemma

[Nate45]

Nice work! I have a question though. What are you using as a spring stop/plunger seal so it doesn't go in the area with the spring? Thanks!

[Ryan201821]

Nice work! I have a question though. What are you using as a spring stop/plunger seal so it doesn't go in the area with the spring? Thanks!

String stop, and a skirt seal. Might want to read the thread. Or look at pictures.