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Thread: Stacked tube breech backpressure

  1. #11
    Insider new ion?'s Avatar
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    Sooo...

    I thought I had a bright idea in rearranging an Axe drivetrain, but somehow forgot about the open force applied from the dump chamber. A slight re-arrangement of that inprogress idea led me to this - with a shielded flow restriction to the left face of this poppet, and chamber pressure applied to the head, I made an increasing force MQ!



    If you dump the middle air chamber from the valve housing, which is connected to the air on the left face of the poppet at a higher flow rate than it's flowing in, the poppet would open. Of course you'd have to flow restrict this air going to the head, or else you'd probably end up with a valve that opens on air-up.

    Words are failing me atm, I'm sorry if I confused you or made you feel like you wasted your time.

    Thinking that the idea of a stacked tube, closed bolt gun that's somewhat modern isn't worth thinking about.

  2. #12
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    Your valve opening speed would be abysmal, and you're actually pretty insensitive to breech pressure in this case.

    The mini drivetrain works because it uses the bolt as a "secondary solenoid" to dump air to the poppet face and speed the opening dynamic, and then closes based on the pressure balance from a chamber (like insight or GEO2).

    There is a solution to this problem that we already use in the Paragon, but it could be adapted. Although it's not optimal for the way this geometry is set up.
    Last edited by Lurker27; 09-15-2014 at 10:32 AM. Reason: reasons

  3. #13
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    I like the idea of a modern closed bolt marker and think there are certain aspects of performance it could have over most (but not all) open bolt engines...but they all require at the very least 2 3 way solenoids, and in most iterations you're using way more activation time, which either means indirect acting solenoids, or latching type. Basically, it's a pain, especially given the confines of what people will be expecting in terms of the ergonomics of a modern package.

  4. #14
    Insider PBSteve's Avatar
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    Quote Originally Posted by Lurker27 View Post
    I like the idea of a modern closed bolt marker and think there are certain aspects of performance it could have over most (but not all) open bolt engines...but they all require at the very least 2 3 way solenoids
    But... but Y0da's Ion...
    Ever so many citizens of this republic think they ought to believe that the Universe is a monarchy, and therefore they are always at odds with the republic. -Alan Watts

    I work for the company building the Paragon

  5. #15
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    There are plenty of counterexamples of single solenoid closed bolt systems. They just aren't very viable, IMO, in the context of the modern gun because of how they interact with the eye system.

  6. #16
    Insider PBSteve's Avatar
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    Not sure I follow. Why is there an issue?
    Ever so many citizens of this republic think they ought to believe that the Universe is a monarchy, and therefore they are always at odds with the republic. -Alan Watts

    I work for the company building the Paragon

  7. #17
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    If you start the bolt chambered and initialize the firing cycle with 1 input, you need a second input to control the closure of the bolt as an independent event. The alternative is leaving a solenoid actuated indefinitely while waiting for a ball.

    This is viable in theory, but in practice requires either a latching noid (the mini/axe noid would do nicely, actually), or living with the current draw of an indirect solenoid for a very long time in some cases. You can handle this with a timeout resulting in a dry fire, but that's obviously suboptimal.

    In short, leaning on a single solenoid in a system where the bolt hold forward time and the bolt open time are both subject to variation means that you have unpredictable variations and dwell which have to be dealt with on the solenoid level. And, yea, it's probably easier to get the latching noid than doubling up the space requirement for a second solenoid outright.

  8. #18
    Insider PBSteve's Avatar
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    Quote Originally Posted by Lurker27 View Post
    This is viable in theory, but in practice requires either a latching noid (the mini/axe noid would do nicely, actually), or living with the current draw of an indirect solenoid for a very long time in some cases. You can handle this with a timeout resulting in a dry fire, but that's obviously suboptimal.
    We've had this conversation before, suffice it to say I'm not convinced this is a huge problem even with a direct acting solenoid.
    Ever so many citizens of this republic think they ought to believe that the Universe is a monarchy, and therefore they are always at odds with the republic. -Alan Watts

    I work for the company building the Paragon

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