Yes, my diagram is a little deceiving though. the beige barrel and the brown piece both slide and the bash open the poppet. the air pressure from the open poppet pushes the barrel back the the original cocked position and the air finally escapes. The beige barrel is actually supposes to extend THROUGH the brown piece a little to provide surface area to recock.bluerussetboy wrote:when your barrel slides onto #4-poppet valve wont that seal the barrel?
You mean like this?mopherman wrote:Alrighty, another hammer idea from me. probably thought up years ago by a certain epoxy enthusiast
hectmarr wrote:You have to make many weapons, because this field is long and short life
Yup, I'm going to make the hammer carriage pipe a tiny bit coaxial so i can have some wiggle room. btw, does anybody know how to find out how much force a spring exerts, other than putting it on my bathroom scale?jackssmirkingrevenge wrote:One slight concern is the size of the port that 4 is sealing, it's going to need a fairly hefty whack to open it even at relatively low pressure.mopherman wrote:Alrighty, another hammer idea from me. probably thought up years ago by a certain epoxy enthusiast
hectmarr wrote:You have to make many weapons, because this field is long and short life
Not accurate at all according to the 'rentsjackssmirkingrevenge wrote:Nothing wrong with the bathroon scale if it's accurate enough.
anyway, would the spring pressure be in N?well, as for mass, I was thinking i would just keep stacking washers untill i find a good weight for my spring. Frankly, I cant do s hit about the spring. lolant wrote:Yeah I was just ganna say. I made this design work in my P.4 Project I also have a design there of the auto blow forward bolt thingy. I made an animation in interactive physics and it all seems to work. Atm I am looking at the physics behind it, I will go from the formulas to the real thing. As the masses, spring tension, air pressure and speeds are very important I will go to it this way. From experience I noticed that it will be very hard to find the right hammer mass and springs using trial and error. I will report in when I am finished with the calculations. Like this I hope I will give a (broad)bandwidth for a working automatic breech system. Btw good luck with ur airgun. I made mine using copper and aluminium pipes; it should work with pvc pipes. This design gives u a high effeciency and high power so I wonder how it would work on the big scale:)
Well the prepressure on the spring can be varied. So for a spring u have different springs with different k costants and you can give is different x prepressures. This makes it so complicated. Maybe a very heavy hammer with a certain prepressured'' spring would give a bigger bandwidth for opperating pressures the automatic cycle would work at.mopherman wrote: well, as for mass, I was thinking i would just keep stacking washers untill i find a good weight for my spring. Frankly, I cant do s hit about the spring. lol
The problem is that the valve I used on that gun I was never able to remake as it kept leaking. The valves I use now are easier in remaking but have less airflow I think; so I should work on that. I work with 8mm innerdiameter piping for the barrel to fit into. (the barrel is the hammer) My valve heads that I use now are about 9mm in diameter. The outercopper pipping I uses is 10mm. So it gives little space for the air to flow-by. I run at 7atms of pressure now. I think I did as well when the movie was made. But I didnt have a compressor with gauge back then. I think a good valve with sufficient space for air to flow by is one of the keys to this automatic design.mopherman wrote:Alright, ant. What diameter openings do you usually use? I'm begining to think that 3/4 is massively to large, but my carriage spring is like 5/8 in o/d. I think i can choke the carriage to 1/2 towards the end though. what pressures do you run at?
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