[y0da900]

A little more evolution to the project. Figured out a nice way to make these without requiring permanent modification to any metal of the Ion, but it needs a channel cut out of the plastic body between the can and the frame to run the hose to the rear air port. These are quite a bit easier to make with the step that stops the valve forward motion on the piston and not inside the power tube. That, and I'm just getting better at machining and made a digital read out for the tail stock of my lathe letting me drill to a precise depth very easily.

Still no good HPA testing, Gander Mountain was the only place around here within quite a ways to get an air fill, and they quit doing them a few months ago. There is an X-ball field on the County fair grounds down the road from me, but their site hasn't been updated since the beginning of the 2009 season, and nobody is ever there when I try to go and see if I can get a fill.

Flow in this version is a little better than the prototype version I originally posted, the main restriction at the front of the power tube has gone from .241" to .281". The main bore in the power tube also got a bit bigger, using aluminum instead of Delrin let me thin the walls a bit.

[p3ngu!n]

Originally Posted by y0da900

Or I could just put an LPR in to feed the front of the bolt for the return air, and use just a high enough pressure for proper cycling. It would close faster, but open slower.

Right now, the only gas vented to atmosphere is the gas behind the valve piston, and that is an incredibly small amount of air. The way it's balanced, I could probably use an LPR to feed that and the air in front of the bolt and get a slight increase in efficiency, but I doubt enough to make the extra complexity worth it.

You should try it with an lpr. That would allow you to open the bolt at a speed which would allow non force feeds, and run smoother at the same time. Have you thought about using a spring to make it closed bolt??? You could then use an lpr to cycle the bolt backwards, and vent the air to close the bolt. Similar to the way a shocker with the spring mod works.

[y0da900]

Opening the bolt slower will not help it feed faster, it will have the exact opposite effect.

No air is vented to cycle the bolt right now, doing so would cause it to lose efficiency, and require a second solenoid valve. There is also no room for a spring to act on the bolt in this.

[p3ngu!n]

???? Why would you need a second solenoid to vent the air? Couldn't you add an exhaust valve instead?

The ion vented air and dint require 2 solenoids.

[y0da900]

You can't vent from a QEV unless you are venting the source pressure from somewhere already, namely from the solenoid valve. The solenoid valve in this is already being used to cycle the piston, cycling something else using vented pressure would require an additional valve.

[asfaraslogic]

That seems like a sweet setup. Can't wait for the finished product, I might have to save my ION for just this project...

[Loganinderrieden23]

omg very cool

[imAllAboutThePB]

why did you just randomly stop working on this?

[y0da900]

I didn't. The newest variation went to the person doing quality and quantitative testing for me (i.e. real world testing) yesterday. It's the third or fourth variant that he's receiving to do testing on. They just haven't been visually much different. The last one that had pics posted is the one he first received, the second (or third, I can't remember) was a variant closer to the original one that I posted with the step inside the power tube and not on the piston (a little more difficult to make, but we were having issues with the other one that may or may not be a manufacturing defect with his gun). The one I sent yesterday is similar to the last one posted, but has a larger power tube, plunger piece, and the ID of the bolt is larger. Larger flow paths, and a smaller surface area driving the bolt forward so it should be slightly easier on paint.

[Spitlebug]

Now this is really turning into a sexy beast!!

[y0da900]

Thanks Bug. I should have taken pics of the last set I sent out, definitely my cleanest yet. But I was in a rush to get it out and it went straight from the machines, to my gun, to the package to be mailed.

[P0E (Banned)]

Am I correct in assuming the back two valve piston seals are not the same diameter? With the rear seal being larger, holding the valve piston in the rearward position? If not, what prevents the valve piston from bouncing off the rear stop and ending up partially forward (nelson farting)?

Have you considered minimizing the bolt's ID to that of the valve piston's front seal? This will eliminate the front of portion of the center guide (light blue portion in your animation), reduce o-ring count, further minimize your pre-expansion, increase flow and increase bolt cycle speed. It also might give you enough room to use a spring for the bolt return (similar to your "Closed Bolt Dumper" animation)? Are there problems/benefits with using a spring instead of the air supply? Could this eliminate the sail seal and increase bolt speed?

How about running higher pressures, devolumizing the chamber and running simple ball bearing LPR feeding the solenoid? Since the valve piston is mostly balanced, it's operating pressure could vary wildly and still not effect operation? Higher chamber pressures should reduce required chamber pressure flow thus reducing shootdown, right?

When running the efficiency test, please weigh the bag of balls and record velocity as you go. Efficiency tests are mostly useless without at least those stats. 2300 shots at 250fps equates to 1597 shots at 300fps. Additionally ball weight varies more than ball diameter in my experience. From high end to low end I've easily seen 20% difference. That's a few hundred balls right there.

Interesting build. Hats off to you.

[y0da900]

Originally Posted by P0E

Am I correct in assuming the back two valve piston seals are not the same diameter? With the rear seal being larger, holding the valve piston in the rearward position? If not, what prevents the valve piston from bouncing off the rear stop and ending up partially forward (nelson farting)?

They are the same diameter, but varying them would not alter the bias any as the controlling factor for that would be the ID of the rear end of the firing can that they ride in. There is enough static friction that it doesn't bounce back, at least not far enough to effect the firing cycle any.

Originally Posted by P0E

Have you considered minimizing the bolt's ID to that of the valve piston's front seal? This will eliminate the front of portion of the center guide (light blue portion in your animation), reduce o-ring count, further minimize your pre-expansion, increase flow and increase bolt cycle speed. It also might give you enough room to use a spring for the bolt return (similar to your "Closed Bolt Dumper" animation)? Are there problems/benefits with using a spring instead of the air supply? Could this eliminate the sail seal and increase bolt speed?

Yes, I have. I've made one that works somewhat that way, but couldn't get it working reliably (I plan on revisiting it soon). Having this retrofit into an Ion body severely limits the potential methods to have a valve like this though. To have a system that moves the seal all the way to the front like in the "Closed Bolt dumper" animation, the rear bore at the back of the firing can needs to be longer than that of an Ion. I have a variation of that drawn to retrofit into a GCPB body, but haven't made it yet. A spring wouldn't increase the speed any though, and I don't see any advantage to using one over air here. The air at the front of the bolt is not vented in the cycle, and not lost for use.

Originally Posted by P0E

How about running higher pressures, devolumizing the chamber and running simple ball bearing LPR feeding the solenoid? Since the valve piston is mostly balanced, it's operating pressure could vary wildly and still not effect operation? Higher chamber pressures should reduce required chamber pressure flow thus reducing shootdown, right?

The last sentence of that doesn't make a lot of sense?? Leafy is testing it in an Epiphany, varying the chamber volume to pressure ratio is one of the things he will be playing with. Yes, an LPR could be used, but so little air is used in that portion of the system the gains would be negligible. Unless it was fired mechanically, which would probably result in a lighter trigger pull. Possible, but difficult to do cleanly in an Ion retrofit. It would be better suited for use in a gun designed around this from the ground up.

Originally Posted by P0E

When running the efficiency test, please weigh the bag of balls and record velocity as you go. Efficiency tests are mostly useless without at least those stats. 2300 shots at 250fps equates to 1597 shots at 300fps. Additionally ball weight varies more than ball diameter in my experience. From high end to low end I've easily seen 20% difference. That's a few hundred balls right there.

I'll ask him to try and get some weights when testing, that is a good point. I tried to make it pretty clear that my early numbers were at a playable but unverified velocity, it's entirely possible (and likely) that they are off one way or the other.

Originally Posted by P0E

Interesting build. Hats off to you.

Thank you.

[P0E (Banned)]

Originally Posted by y0da900

They are the same diameter, but varying them would not alter the bias any as the controlling factor for that would be the ID of the rear end of the firing can that they ride in. There is enough static friction that it doesn't bounce back, at least not far enough to effect the firing cycle any.

Understood. When I refer to the 'seal' I'm referring to the point where the o-ring slides on the metal. I wasn't sure if you tapered/stepped that back portion to allow the bolt to be held open if desired. A ten mil taper/step should be plenty.

A good way to verify it's not bouncing might be to check for misfires/chops when fired straight down vs level? If the piston does bounce, it will be at its worse when pointed down. Possibly resulting in the bolt short stroking?

Originally Posted by y0da900

Yes, I have. I've made one that works somewhat that way, but couldn't get it working reliably (I plan on revisiting it soon). Having this retrofit into an Ion body severely limits the potential methods to have a valve like this though. To have a system that moves the seal all the way to the front like in the "Closed Bolt dumper" animation, the rear bore at the back of the firing can needs to be longer than that of an Ion. I have a variation of that drawn to retrofit into a GCPB body, but haven't made it yet. A spring wouldn't increase the speed any though, and I don't see any advantage to using one over air here. The air at the front of the bolt is not vented in the cycle, and not lost for use.

The "Closed Bolt Dumper" reference was only in regards to the use of a spring. Forget the spring for now. In this concept the seal does not move all the way forward. Imagine using identical parts, minus the power tube, with the bolt ID small enough to ride on the valve piston head seal. Operation is identical except:
- The bolt has more surface area resulting in faster forward bolt speed.
- Lack of power tube increases flow.
- Smaller bolt ID decreases pre-expansion.
- Fewer O-rings

I only brought up the spring because some air-pressure bolt return prototypes have issues with slow forward bolt movement. i.e. The bolt doesn't move until the chamber is completely full. Additionally the chamber fills and the regulator compensates before the bolt is fully forward. Now the bolt is trying to compress the 100psi instead of pushing it back.

Originally Posted by y0da900

The last sentence of that doesn't make a lot of sense?? Leafy is testing it in an Epiphany, varying the chamber volume to pressure ratio is one of the things he will be playing with. Yes, an LPR could be used, but so little air is used in that portion of the system the gains would be negligible. Unless it was fired mechanically, which would probably result in a lighter trigger pull. Possible, but difficult to do cleanly in an Ion retrofit. It would be better suited for use in a gun designed around this from the ground up.

Sorry. That last sentence wasn't written very clearly. If your chamber is smaller yet fed with higher pressure it should fill quicker. e.g. It takes longer to fill 2ci with a 100psi source than 0.5ci with a 400psi source...for a given conduit?

The LPR idea wasn't to reduce the vented gas at 100psi. Instead it was to allow a higher chamber pressure while still using low pressure solenoids. Additionally, as chamber volumes lower, and chamber pressures rise, the volume between solenoid and valve piston starts to be come significant. When this happens you will need to waste less gas out the back.

Originally Posted by y0da900

I'll ask him to try and get some weights when testing, that is a good point. I tried to make it pretty clear that my early numbers were at a playable but unverified velocity, it's entirely possible (and likely) that they are off one way or the other.

Understood. I just wanted to make sure. All markers out there are less than 70% efficient and I feel this has real promise to break 80%.

[Leafy]

Poe the gun wouldn't work right in the ion without the power tube because of how the body is made. If you were to make a body just for this design then you could completely get rid of the power tube.

I've almost got my version of the bolt kit working, at the moment the rod doesn't seem to want to go all the way back and seal the dump chamber and I also have only dead batteries and I'm just getting it shooting with a smav3.

[P0E (Banned)]

Originally Posted by Leafy

Poe the gun wouldn't work right in the ion without the power tube because of how the body is made.
...

Could you elaborate? I do not have one in front of me, but I have the CAD drawings and animations.

[y0da900]

It should theoretically work fine without the power tube in the way he's describing, but it still needs a positive forward stop for the piston and a positive rearward stop for the bolt. Essentially flip the power tube backwards and have it only stop the movement, not do any sealing. I have one built, didn't work well. I think it was poorly machined and I plan on trying it again.



I'm assuming that's more or less what you're talking about P0E?

Hopefully devolumizing gets some good results.

[Spitlebug]

We gotta get you an anno setup.

[rjones1213]

conversion kits are going to be awesome! I will actually buy an ion just to buy the conversion kit

[P0E (Banned)]

Originally Posted by y0da900

I'm assuming that's more or less what you're talking about P0E?
...
..it still needs a positive forward stop for the piston and a positive rearward stop for the bolt.

That's almost identical to what I was thinking. Except in my head the power tube was completely gone and the front of the piston had 0.2" long fins that kept it centered while fully retract. The rear most piston seal provided the forward stop since it was larger than the center seal. Basically identical, except the one in my head is harder to make, more fragile and might involve removing too much metal from the back of the chamber.

If you were to start with a custom chamber, would you increase the valve piston diameter? Maybe a DP threshold/G3 would be an ideal platform to modify?

One more idea, have you considered a MQ style vent behind the piston instead of piping an air supply to push it forward and then vent. Just imagine your piston as the piston in the MQ. Less gas wasted, faster and simpler.

How long does that MQ patent have left?

Originally Posted by y0da900

I have one built, didn't work well. I think it was poorly machined and I plan on trying it again.

What exactly was it (not) doing?

If the bolt wasn't open long enough or if it didn't appear to open completely, the cause might be found in the faster bolt speed, starts moving sooner and starts closing later. The Ion's dwell just wasn't long enough?

[y0da900]

The reason an Ion is so ideal for this is several fold.

• Hoses don't limit where the solenoid can divert air
• They're concentric and easy to make new parts for (G3 rear chamber has an eccentric lobe)
• They're super cheap

I have thought about using an MQ like assembly for it, but I've never tried it. I don't think it would be any faster though. Good potential for a really modular system that would only need minimal air and electrical connections.


The one I've made only partly cycled and would bind, I'm sure I just had poor tolerances on it. I'll need to get a reamer for the next one I make so the valve seal can slide freely enough.


Yes, I need anodizing equipment. I think I have most of what I would need floating around, just need to hunt down some sulfuric acid and make a safe area for it.