Author Topic: Smith Rev3 build (Read 14934 times))

csdilligaf · « **on:** January 25, 2014, 12:14:51 PM »

I figured I would start a build thread for my project allready underway. Here is a few pics to get started.

rsterne · « **Reply #1 on:** January 25, 2014, 02:43:01 PM »

Beautiful design and workmanship.... I can see the flow-through bolt and I assume the valve lives directly below that in the upper chamber in the receiver.... Is the lower chamber for the air reservoir / regulated tank to attach to?.... I am curious as to the airflow path, with your balanced valve design, and that receiver layout, I'm guessing that the airflow travels back from the regulator, turns 90* up into the front portion of the valve, back 90* through the valve, up 90* into the transfer port, then forward 90* into the barrel?....

How much plenum volume is available between the regulator output (pin valve, if any) and the valve seat?.... I mean usable volume that the valve can draw from during the shot, ie the air available to provide energy to the pellet without the regulator having to cycle?.... This is truly a different design than I have seen before, and I want to fully understand it....

Bob

csdilligaf · « **Reply #2 on:** January 25, 2014, 04:07:43 PM »

Thanks, I love to machine. And Yes there is a 460cc 1.5" titanium tube with a Regulator that goes into the bottom hole. The air flows from the bottome chamber thru a .375" hole upward just around where the spring and knurled cap join in the middle chamber. When the air goes past the vavle it travels upward at an angle so that it is a more smooth flow. The hole in the valve body is at an angle but matches up with the vertical hole in the action. Where I drill the transfer is under the scope rail then I tap it and make a threaded plug with an o ring and a pin that is the same size as the transfer port. Then I install it and drill the probe hole the there is a seamless diameter there.
As for the prechamber volume between the reg and head of the valve there is a total of 3.56" x .60" dia volume. I dont know how you guys look at that, cubic inches, cubic centimeters or the weight of moon dust that can fill that cavity? You guys are way over my head with the math stuff. Me, I make a change, try it, tear it down, remake it and start over. I swear from the looks of things you guys have an Iphone app for everything. I just this month got rid of my Razor flip phone. So I have some catching up to do.
The trigger is an Anschutz 5065 unit and the barrel was a one of Brux barrel they did. It is a .22 cal with the correct bore and groove for JSB pellets and a little slower twist, about 20" twist. Here is the Rev2 version. It was so big it is known as "Sumo"

Ands its Twin tanked externally adjustable reg. brother "Sumo II"

Rdsail · « **Reply #3 on:** January 25, 2014, 04:11:39 PM »

beautiful work! I wish I had have half the talent.

sgeorge · « **Reply #4 on:** January 25, 2014, 05:05:57 PM »

Chip,

See you're showing off again. That twin tubed monstrosity looks very familiar. You need to post a picture of a group from that Brux barrel. Have you heard a sponsor of the 2014 National Championship is offering $500.00 for a 250 shot in any class?

rsterne · « **Reply #5 on:** January 25, 2014, 05:27:07 PM »

Chip, first of all let me tell you I'm MOST impressed with your rifle, not only the design, but the quality of the machining makes me drool.... When I see stuff like that, it makes me green with envy.... I don't know if you've ever seen any of my builds, but you might find my Hayabusa interesting, although not up to your standards.... It's just below in the Machine Shop Gate, along with my Millenium Pumper project.... Don't let me scare you with the math, I'm a bit of a Geek (a bit?!?) so I like to come up with formulas to describe what we (the collective we, welcome to the group) find happening in the real world.... so not a theorist, per se, more of just trying to put numbers to a very complex subject....

Your valve air path sounds a lot like what I use in my Disco/Hayabusa valves, where the port slopes 20-30 degrees from the vertical towards the valve throat to ease the air around the corner from the throat to the (vertical) transfer port.... With a 3/8" passage from the pre-chamber (plenum) to the valve, you certainly have all the air in there "on tap" for the valve to draw from.... I have a rule of thumb I like to use for plenum size of 1 cc per FPE that the rifle is designed for.... When the shot occurs, the pressure in the valve and plenum drops, and the smaller it is, the more it drops, which reduces the AVERAGE pressure during the shot, and makes the gun think it has less pressure to work with than the regulator setpoint.... On a 2000 psi gun, that drop is about 10% with a 1cc/FPE plenum (assuming 1 FPE/CI efficiency), heres a graph for a 45 FPE MRod regulated to 2000 psi, ust to give you an example....

As you can see, with a 45cc plenum, you lose about 2 FPE, cut that in half to 23cc, you lose about 4.5 FPE (so 10% of 45).... The lower the regulator pressure, the greater the percentage loss, but I would say you're pretty much in the ballpark to not be dropping too much power and efficiency.... Your pre-chamber is 1.00 CI (16.4 cc) and if that doesn't include the volume in the valve itself, you would be over 20cc.... so the pressure drop per shot wouldn't be enough to lose sleep over....

BTW, I live in the sticks, no cell service here.... so what's an iPhone?.... *LOL*....

Bob

lloyd-ss · « **Reply #6 on:** January 25, 2014, 07:24:43 PM »

Chip,
Beautiful work! Very interesting layout with the barrel set between the twin reservoir tubes. Thanks for sharing this with us.
Lloyd

PetefromTn · « **Reply #7 on:** January 25, 2014, 09:45:36 PM »

Chip,
Nice to see you here man. That monster is coming along nicely. I hope you get what you want out of it. Still working on my build and I hope to post some pics of it just as soon as I have something to show LOL. Nice work man. Peace

Pete

csdilligaf · « **Reply #8 on:** January 26, 2014, 11:18:30 AM »

Thanks guys, I will try to keep up on the posting as I progress. Steve, I'm just getting some pics or your rig out there so when you show up in Arizona people will know what it is. It just looks like something mounted on the car from "Back to the Future" and I dont want people confused.

csdilligaf · « **Reply #9 on:** January 26, 2014, 11:22:05 AM »

Lloyd, It was Dan Brown who did the twin tube layout and built the Regulator. The reg is below the barrel where the pressure tube normall is. Dan is the go to guy for reg design and building.

csdilligaf · « **Reply #10 on:** January 26, 2014, 11:45:37 AM »

rsterne, It seems you all are more into the big bore stuff. So if you wanting 100 fpe you would recomend a 100cc plenum? I ask because the FX line of airguns I believe to be the pinacle of performance. The .22 cal and .25 cal with a plenum of maybe 11-12cc will get 70 shots at 50 fpe with a spread of 15fs before it goes off the reg on a 500cc bottle. I would love them but the quality of the build is not to my expectation. I hope someday I can get that performance in my build with my quality. In the back of my mind that is one thing that got me over here to GTA. I think we can only go so far with a design or idea and new eye's on it can turn the corner and make advancement. Maybe we all gain something. I see Lloyds mutation on the balanced valve and that is just what I mean about new eyes on it. I played with it about 5 years ago. I was trying to have zero valve head pressure and use only the spring to hold the valve shut. It did not go very well. Then sometime ago FX and another person started doing it with about 50% reduction with the stem being less than the head dia. And now Lloyds version can maybe make big bore power with a small bore hammer and spring.
Sounds to me like we need to have a Vulcan mind meld and develope a .30 cal for next years AOA Extreme benchrest!

csdilligaf · « **Reply #11 on:** January 26, 2014, 12:10:37 PM »

Here is my Hammer. Not a simple one to make. The bolt has a pin to catch in the slot which also is used to keep the bolt from rotating. The sear has to catch on one edge and the sear also needs another edge to reset the sear. It is hollow with the spring inside and weighs 51 gram, has .25" travel with zero pre load on the hammer spring. The spring is a Gardner .48 x .055 x 2.0 SS that has a spring rate of 16 psi.

Rdsail · « **Reply #12 on:** January 26, 2014, 12:14:37 PM »

Just throwing one more thing on the pot. I wonder if there would be a huge benefit by adding an electronic trigger. A solenoid to open the valve. By having the ability to adjust the length of the valve opening and duration. Just a crazy thought.

PetefromTn · « **Reply #13 on:** January 26, 2014, 01:24:13 PM »

Quote from: csdilligaf on January 26, 2014, 12:10:37 PM

Here is my Hammer. Not a simple one to make. The bolt has a pin to catch in the slot which also is used to keep the bolt from rotating. The sear has to catch on one edge and the sear also needs another edge to reset the sear. It is hollow with the spring inside and weighs 51 gram, has .25" travel with zero pre load on the hammer spring. The spring is a Gardner .48 x .055 x 2.0 SS that has a spring rate of 16 psi.

Interesting hammer design. does it have an adjustable head insert or something? That Anschutz Trigger looks pretty nice how do you like it? I am working on my own design trigger here and it is not ready to be machined yet. Most of the valves I have made have been with a steel shaft and delrin head against an aluminum valve body with a thinned lip to aid sealing. How do you think an aluminum valve body with steel shaft and PEEK head would work out, is the PEEK really hard IE too hard to aid a good sealing. I usually lap my valve heads in to the seat so it typically works well without much valve spring setup. Also what is the purpose of the gnurled ring on the valve spring retainer in the pictures. I do not own a Rapid so I am kinda unsure of the design layout short of the basics. Peace

Pete

csdilligaf · « **Reply #14 on:** January 26, 2014, 02:14:42 PM »

The thread in the hammer head is for a little threaded extension. It just was not in for the picture but was when I weighed it. It allows me to change the length of the hammer travel by changing the length of it. The knurled part next to the spring is a little cap that holds an o ring to prevent air leaking. The .125" dia shaft on the high pressure side of the valve head is vented to outside. This reduces the force it takes to open the valve.
The Anschutz trigger is simply awesome. But for $450 it better be. I had it laying around and needed it to be used otherwise I would have used a Dawson trigger.

rsterne · « **Reply #15 on:** January 26, 2014, 02:23:56 PM »

Chip, yes, in a 100 FPE gun I would strive for a 100cc plenum.... You can use a much smaller plenum than 1cc / FPE, but you have to compensate by increasing the regulator setpoint to maintain the average pressure during the shot....

While Lloyd and I enjoy playing with the big-bore stuff, I think we do it because pushing the envelope allows us to learn more, at least that is what I find.... My highest specific power output, relative to caliber, is I guess my .257 Hayabusa, which has topped 160 FPE and can be tuned for a nice 10-14 shot string at 130-135 FPE with a 4% ES with bullets from 66-88 gr.... The same gun, in .308 cal has topped 200 FPE, and in .357 cal is over 250 FPE.... It can also be used in .224 cal, shooting 41.5 gr. RWS swaged bullet like they use in Holland for 100M benchrest and get 14 shots within a 2% ES at over 1000 fps (90 FPE) or tethered at 2800 psi and shoot all day at about 1040 fps with less than a 1% ES....

You mention the .30 cal, are you aware that Sean Pero and I developed a .300" groove, .293" land, 26" twist barrel specifically for the new JSB pellets?.... Then, as icing on the cake, I designed an 70 gr. Rebated Boattail bullet to go with it.... Sean has pushed it into the mid 900s (160 FPE) with near MOA accuracy in initial tests, so we're quite pleased.... I can't tell you what the BC is yet, we haven't measured it, but the theory says about 0.160 below 960 fps....

Bob

PetefromTn · « **Reply #16 on:** January 26, 2014, 03:28:58 PM »

Who built the barrel for you? I have considered making another action in more of a big bore once my new FT rifle is completed. A .30 would be fun especially since they now make lead for it from several sources. Peace

Pete

csdilligaf · « **Reply #17 on:** January 26, 2014, 04:36:16 PM »

My .30 cal barrel was made by Rocky Mountain Rifle Works in Co. I will have to look up the Sean Pero barrel, is there a thread?

rsterne · « **Reply #18 on:** January 26, 2014, 06:24:08 PM »

Original thread....

http://www.gatewaytoairguns.org/GTA/index.php?topic=44889.0

More here....

http://www.gatewaytoairguns.org/GTA/index.php?topic=46367.100

Bob

michaelthomas · « **Reply #19 on:** January 26, 2014, 11:40:54 PM »

Very cool rifle.......and really, really beautiful work.

I recognize the picture of Steve's rifle from the USA Benchrest site.

Nice!

Mike

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Smith Rev3 build

Author Topic: Smith Rev3 build (Read 14934 times))

sgeorge