Intank regulator project…
Hello Guys,
I thought I publish my project so far. I have been designing new regulator which will go inside main tank. The reasons are simple;
-it won’t take space between gun and tank
-it’s safe since everything is inside tank
-the big forces are all gone and replaced from stretching to compress
-there is good space for relatively big size regulator chamber which is needed (25ccm) for low pressure and wider pressure-range (more usable shots)
-the firing valve is separated from regulator design so one could use any valve available (although it needs connection thread for regchamber)
I already built two prototypes and tested them on dedicated testbench. The regulation works. I did few hundred of strokes and it regulates the pressure everytime to set value. I still need to examine different poppet-valve sealing materials since I am not 100% happy with current implementation. Over few hour period there is some pressure grawling noticeable meaning that first shot will be little faster than rest.
The difficulty for Talon regulator is the filling. It has to be able to handle bigger forces during filling and also has to pass trhough the air from regchamber to the tank. That was the reason for “inventing” poppet-valve to the regulator. It handles both. Eliminates the bigger forces against regulator-sealing and acts as oneway-valve during filling.
The regulator is designed for 300bar and the regulator body can handle 3x that pressure when it comes to strength.
When used with 100bar pressurerange the accuracy from first to last shot is about 1.6% leading to 1.2m/s velocity drop over whole range. Of course there is little bigger variation during string because of other factors.
This is how it should be assembled to the gun….
The princible of regulator…..
-spring lifts poppet-valve’s stem and air starts to flow from tank over valvestem to the regulator chamber
-pressure in regchamber raises and exceeds springdiscs force and regulator pistons moves to the right. Poppetvalve closes.
-shoot and the cycle restarts
-during refill the overpressure in regulator chamber (against tank) will push the poppet-valve open and air will flow to tank
-the regulation pressure is adjusted with big M14x0.5 thread in the “tophat”
-do realise that the flowchannel in poppetvalve is 10x smaller than through the regulator piston. The pressure is always same one bothsides of piston’s heads. So don’t get confused about the “reverse” design.
The parts….
Prototype number two…
Poppet-valve and integerated sealing…
About the scale of parts….
Bench testing….
In the bench the regulator is inside aluminium tube…
It’s not ready yet but it’s a step closer to our common goal… regulated Talon which can shoot consistent shots with wider pressure-range and wider ME range. Next I need to build or get main firingvalve to be able to perform some fieldtests with gun.
All Replies
Mika,
One thing I forgot. Make yourself a new ring in the back of the gun the bottle screws in. Airforce uses shit tolerances and when you tighten the grubscrew you push that ring out of alinement. Use a heavy push fit and then your grubscrew and you might get rid of the breechslide issue.
Hope this amkes sence.
Regards,
Marc
Mika,
That’s some results you got there!! I’m impressed with how well it works.
Might take a while before I can finish the valve becouse my lathe is broke at the moment. Can’t do any screw cutting. Turns out I have play in my leadscrew, and that fucks up my screwcutting.
I can send you the parts I have already done?
Regards,
Marc
Yes indeed. I think you guys misunderstood the chart.
The regulation STOPPED at 150bar as planned (shot num 85) since the tank pressure reached regulated pressure. Then the firing valve just semiregulated like usually.
Once I set the regulator pressure to 110-120 bar it’s a flat curve all the way to shot 150. I will also try to experiment with valvestem bores if I could get more energy out of regulatorchamber with sub 100bar pressure and extend the shotcount even more.
You mean the first shots? I will study this little more. With heavier hammer and propably little heavier hammer spring it will be no issue.
The regulator is very simple. Look at the 3D-pic and remember that the pressure in both sides of piston is always same. There is hole through the piston. The small bleedingvalve has 0.5mm bore. The air comes from tank through that and fills the regulator chamber. WHen the pressure in chamber is in certain level the force in regulator piston pushes it to the left and it closes the bleeding.
THe pressure is adjusted with “tophat” in the rear of regulator. Turning the hat will move bleeding valve further or closer to regulator piston. So the pressure needed to counter the springdiscs is lower or higher.
The secondary piston is also oneway-valve. During fill the pressure in tank is smaller than in regulator chamber and bigger pressure will push the secondary piston to the left and forcing the bleeding channel open and air will go to tank. Once the pressure in tank is same than in regchamber the secondary piston is in balance (force is same in both sides) and the spring will push it forward to the right.
Shadoh; The regchamber can’t be any smaller or you don’t get enaugh air volume for shot. Actually it should be bigger but there’s no space without modding. I looked AF tank and there is some room to make the M18x1.5 thread bigger. Maybe 20×1.5 or 22×1.5. THen the regchamber could be 18 or 20mm OD and the volume is much bigger.
The key for shotcount is to use the widest pressure-range possible. But at the sametime when the regulated pressure is smaller the regulator chamber size needs to be bigger. It’s not the pressure shooting the pellet but the volume of air. You need about 0.5litres if normal pressure air to get enaugh power (~30fpe). But you need to move that air out of regchamber during firing. The barrel volume is 12ccm (18″ barrel) and that sets the limit for smallest possible regchamber size and the size sets the limit for smallest possible pressure to use.
You could just shorten the regulated chamber so that it didnt take so many shots to get it to 150.
that is so very cool !!!! do you think you can flatten the curve from 85 to 185 ?
but very impressive with so many shots….
to empty the regulator couldnt empty the chamber by dumping a bit of air ? like when you empty a tank out by putting a dime in the fill adaptor….
sad thing with your car….i all most had a simelar experience back in DK…was shooting at bricks made from granulated cement(you know bricks thats light enough to float)…i used these as backstop…and over the summer the pellets dug its way through…i suddenly heard a rock fall out behind…and right enough i had shot through…luckily i noticed this…or i would had shot my neighbourgs new 2000€ automatic garage door
while living at a dorm in DK, i took a shot out the window after some ducks….and heard glass falling….i dont know how…but i had shot my window to pieces
shit happens….
your project is very cool…im having trouble understandig it all…do you have any animations or a video of how it operates ?
I am still quite upset about the morning accident but I put the results to spreadsheet and continued my work on regulator. Crying won’t fix my car anyway 🙁
So here’s some data. I filled the tank to 210bar and set regulator to 150bar which was too high for my hammer(s).
The important thing to read from data is that once I set the regulated pressure for 130bar I should get 150 consistent shots with 280m/s (920fps).
The slope in the beginning is bacause after fill the pressure in regulator chamber is same than fill pressure and apparently it was too much for my standard talon hammer and springs. So it needed almost 10 shots before pressure inside reg dropped to 150bar. After that it started shooting with regulated pressure. The three shots with lower velocity is because I turned PW all the way down to see what it does.
After 50th shot I swapped my own 75 gram hammer which also has better slides. if you compare the shot-to-shot variation with standard hammer and custom hammer you can see that the variation is much smaller with heavier hammer. There is still some slight variation and I found at that the reason is breech slide. When I cocked the gun and returned breech back to tophat even small variation in position affected to velocity 2-3m/s. When I did that very carefully and always to same position the velocity between 2 shots was in decimal accuracy same. Lesson learned. Build new more accurate breech ASAP.
So I swapped the hammer and continued shooting. At 75-85th shot the pressure in tank reached regulated pressure (150bar) and the mainvalve started semiregulating as supposed. The peak velocity was reached near 150th shot when tank pressure was about 130bar. So that is the sweepspot for this regulator setup and is the pressure setting for next tests. I will also lighten the valve return spring which is still 100N and much too high. Once lightened and regulator pressure set to 120-130 bar I should reach 300m/s (1000fps) easily. Although I am VERY very happy about the results already.
Hopefully I can soon posts new string with 150 shots and 30FPE consistent velocity. After that I start pushing the fillpressure and see if I can reach 200 shots 😛
Ooops…you need one of these.
Ouch,
At least it was a headshot so it didn’t suffer too much.
Sorry to hear about that, hang in there.
Roger
-well mate look on the brite side atleast the gun works lol 😛
Yep you killed it 😯 not a good idea to use your pride and joy for a back stop ! 😯 Ive allways used 10mm alloy plate in my pellet box because it allways will be pellet proof 😀 .Suggest you try and tell the wife something that completly removes any blame from you ! Then give in and tell her ………..hehe
I continued my experiments this morning. Everything looked good. Here’s the shooting setup in my small carage. In the front there is 1.5 inch thick doors with metal shield in below. The big cardboardbox filled fit stuff to go to junkyard. Inside the box 2 half inch thick wooden plates. In the front 3rd plate and 4 inch think soft material to kill the noise.
I loaded 200bar to the tank and adjusted reg. pressure to 140 bar. Started shooting and was at shot num 182 when shit happened.
I heard weird hissing sound and immediatelly checked the gun. It was not from there but came from outside. My worst nightmare just came true. Shit shit shit and once again shit. Banged my head few times to the brick wall just to make myself understood how stupid I am.
Oh well. Opened the carage doors and indeed …. I KILLED MY CAR. My precious Audi TT which I always take so good care. See… the alien blood is coming out of it. Oh boy my wife is gonna like this….
New radiator, new front bumber, painting at least 2000$ which I would very much have liked to spend few other things. Not to even mention if the pellets penetrated radiator what happened to engine 🙁
I called insurance and the fella in there falled from chair and asked to repeat slowly.. “You are trying to say that you shot your car by yourself? ”
The lesson learned. When you shoot 200 shots to same spot it doesn’t matter how much wood and stuff you have inbetween. Eventually it will penetrate everything. Oh crap…
😯
You know…. back in the heyday of the TOG, I wondered if the innovations of the time were it… I mean, just how much CAN one do with this platform. I thought all had been done.
It’s people like you that keep the sport of airgunning interesting and particularly so with our guns. Very nice work indeed. I look forward to results.
😯 😯 😯 😯 😯 😯
That guy is crazy! Great work!
Why don’t get an AA S410 and start working on it??? I’d like to see some crazy ideas on that gun 😆
Brilliant absolutely brilliant! :):):)
I love it!
Well don there Mike, have a beer for me eh?!
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That’s some results you got there!! I’m impressed with how well it works.
Might take a while before I can finish the valve becouse my lathe is broke at the moment. Can’t do any screw cutting. Turns out I have play in my leadscrew, and that fucks up my screwcutting.
I can send you the parts I have already done?
Thanks.
Oh shit. I’m sorry to hear about your lathe. Seems like there is some shitty weekened allover. Sure, The new tank would be nice. I can work with my current valve so there is no rush about that. I will send some email to you tomorrow.
Here’s some more data from today tests.
First with 110bar regulated pressure. I filled the tank only to 140bar since I didn’t want sit and shoot 150 shots – just test the velocity with different pressure and settings and see short string how it regulates.
To really understand what that means try to imagine 200bar fill which will provide 3x shotcount than seen below. I shot 14gr pellet with 290m/s and tested few 16gr also which provided 275m/s.
I also went back for mid-power tests. Set regulated pressure to 80bar only and filled tank to 140bar again for same reason than above. If tank is filled to 200bar you can more than double shotcount.
The standard deviation during regulated string is only 0.7m/s and biggest reason is slight creeping of regulated pressure. It takes some time before the regulator piston sealing settles after change of pressure. I tried to perform each shot very similary and with heavier hammer the shot-to-shot variation seems to be quite good already as seen. At the shot 70 the tank pressure reached regulated pressure and I shot few more shots to see what happens. Remember! I started with ONLY 140bar so try to imagine how much longer string it will provide with full fill or slight over fill. I am eager to wait tests with your new tank and starting from 250+ bar 🙂
Next week I will try to examine what I can get out from 20ccm regchamber. I expand the bores in valvestem. I already weakened the spring quite a lot and there seems to be no problem with dump issues even at 60 bar.
ps. Yep. I understood the ring you mentioned. It looks quite ok now but I already had in my mind to make new one. AND if I make new I move to metric threads since that particular thread is pain in the ass in all parts to make 😀