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[y0da900]

Here's a hat variation I came up with today. Trying to come up with one that will work in various valve bodies, but those with flat back ends and those with partly tapered. I imagine the depths are relatively consistent, or spring kits would be wildly incompatible.





Same hat, 2 different valve assemblies. One is standard Nelson, the other is for my valve type on newmaticarsenal's oversized powertube. Both can also be used with standard Nelson springs without the hat, or with smaller springs when using the hat. The ports through the hat are to try and not restrict the flow from the air source.

Lurker, I like your G6R valve by the way. If it is laid out how I think it is, I've been working on something near identical for the last year or so. It would be interesting to run one in a gun with a not front mounted LPR so you could easily run a pressure transducer to the valve shield and see if any air makes its way through the atmospheric vent for further closing bias. I have the porting in mine laid out to try and encourage that, but no idea how much air would make its way up there.

[russc]

So did you find that using the stock cupseal "cup" diameter in the hat was effective for the purpose of closing the valve?

I've been thinking that an elongated cup that flares out towards the rear of the valve would provide a large accessible valve volume, while the pressure differential between the front and back of the valve after a shot would mean we don't need to use o-rings or an overly tight tolerance to get the closing bias that we're looking for.

[y0da900]

Elongated with a rear flare out is how the one I've already built is laid out. Very difficult to get to velocity. By the time I trimmed it down enough to get the speed up, I don't think it was acting effectively but I haven't tested the efficiency since getting the velocity up on it.

[russc]

Interesting. I guess the pressure change acts very quickly to go from neutral to closing bias.

I don't have my laptop at work so I'll have to rely on pen and scanning, but I think a two-part design might help add a time delay to when the closing force kicks in. I'll post it up in a few minutes.

[russc]

here we go. It would have a slightly delayed effect since it is acting on the valve spring rather than directly on the valve. I'd go with a loose oringless tolerance for the rear piston so that we don't have recharge issues. Alternatively, you could have it directly impact the valve hat, maybe with a rod through the middle of the valve spring... Shoebox Shocker style, and spring load the rear piston so it normally sits rearward. You'd just space it so it has a slight delay before it can push the valve closed.

valve_hat.png

Then again, I guess you're going for ease of installation and cross compatibility. My only concern is that we are removing quite a bit of valve volume, which is important when we are looking at lower pressures and high flow.

[russc]

Here's another one, based on the shoebox shocker. Hope you enjoy the quaint cartoon CAD.


valve_hat_2.png

[Lurker27]

Originally Posted by y0da900

Here's a hat variation I came up with today. Trying to come up with one that will work in various valve bodies, but those with flat back ends and those with partly tapered. I imagine the depths are relatively consistent, or spring kits would be wildly incompatible.

http://img35.imageshack.us/img35/536/hatsmodel.jpg

http://img685.imageshack.us/img685/4356/hatsmodel2.jpg

Same hat, 2 different valve assemblies. One is standard Nelson, the other is for my valve type on newmaticarsenal's oversized powertube. Both can also be used with standard Nelson springs without the hat, or with smaller springs when using the hat. The ports through the hat are to try and not restrict the flow from the air source.

Lurker, I like your G6R valve by the way. If it is laid out how I think it is, I've been working on something near identical for the last year or so. It would be interesting to run one in a gun with a not front mounted LPR so you could easily run a pressure transducer to the valve shield and see if any air makes its way through the atmospheric vent for further closing bias. I have the porting in mine laid out to try and encourage that, but no idea how much air would make its way up there.

Air definitely goes through that hole and closes the valve more quickly. 100% sure from testing. Appreciate the props.

Hat looks good. I know it's a quick and dirty, but rounding the exterior edges and maximizing the through ports is the ticket, IMO. Can tune the blowby with the poppet diameter and sandpaper and measure the clearance once it's dialed in, IMO

[ApoC_101]

Hey I just whipped up a modified magic tube today for my Retro, to increase closing force with air pressure... allowed me to use a lighter valve spring no problem. also, I think it's one of the most consistent configs I've tested over the chrono yet. I'm also using a lighter hammer spring now

[ApoC_101]

Yoda, on your hat design you should add a little hole through centerline maybe, to keep the pressure behind the cupseal as high as possible. maybe... just a thought.

[y0da900]

I thought about using a small hole in the back and creating a tighter fit, but I don't think the pressure will escape that fast enough to make much of a difference. Simple enough a piece to make though, crazy not to make 2 and try it.