1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Circular Stroke Piston System

Discussion in 'General Gun Discussions' started by zollen, May 22, 2011.

  1. zollen

    zollen Well-Known Member


    There are two key features I would like to point out.

    1. Thumb Screw Pressure Adjustor for different barrel length or suppressor setup. The thumb screw simply increase or decrease the internal blow back gas pressure for the appropriate operation.

    2. Composite Piston Dish pushes the bolt carrier group for shell extraction and feeds magazine bullet to the chamber. It completes one operation cycle without the need of buffer tube. This feature helps reduce weight and allows the attachment of folding stock.

    3. All key Piston + push arms components are made with heat resistance light weight composite materials.

    4. Hopefully the reduction of recoil would be able to achieved by the absent of buffer spring
    Last edited: May 22, 2011
  2. Sam Cade

    Sam Cade Member

    ummmm... OK.

    Basic nomenclature and typographical errors aside, there are some serious flaws here.
  3. zollen

    zollen Well-Known Member

    Please Please Please tell me. I would like to improve the design.
  4. Sam Cade

    Sam Cade Member

    Its completely unworkable.

    This is like a beta type Stirling steam engine but without constant pressure on the system...

    No real "design" here, I think you are vastly underestimating the complexity of what would have to happen in order to make something like this work.

    Êtes-vous un francophone québécois?
  5. zollen

    zollen Well-Known Member

    Would you be specific other which part of the system that failed? I really want to learn.

    I am a Canadian, but I am not from Quebec. This is only a draft conceptual diagram, not design.

    Are you suggesting I should have used a dual pistons system where each piston regulates one end of the operation?
    Last edited: May 22, 2011
  6. Sam Cade

    Sam Cade Member


    I am suggesting that the entire concept is flawed.

    Reciprocation,to rotary motion,to reciprocation with nary a spring in sight.

    This is just a mess. I think you are trying to say that there is an adjustable gas block.

    Ok. Do you know how much heat the parts have to endure? Do you know how the structural properties of various "composite" materials change when subjected to the kinds of temperatures that the gas system will generate?

    Here is where the fundamental problem lies. Without any sort of spring in the action everything would have to be wildly overgassed in order to get the thing to cycle, also, Its entirely possible to have a folding stock AND the mainspring in the butt stock. The Para-Fal does it just fine.

    Explain that. Keep in mind that recoil is linear along the bore axis.

    So assuming that we are talking about AR type rifles:

    The reciprocation of the buffer inside of the receiver extension actually serves to slow down the recoil impulse getting to the shooter.

    An in-line DGI system like Stoner designed is about as simple as you can make a self loading firearm short of blow back, open bolt, full auto, advance primer ignition buzz-gun.
    Last edited: May 22, 2011
  7. W.E.G.

    W.E.G. Well-Known Member

  8. Unistat

    Unistat Well-Known Member

    I don't want to be negative, and I'm not an engineer anyway, but I do admire your innovative mindset and I think you should keep trying. One of these days someone is going to come up with a true revolution in gun design, why not you?
  9. 4thPointOfContact

    4thPointOfContact Well-Known Member

    I see the flaws thus....
    1) You need a half rotation to extract the fired cartridge
    2) You need a half rotation to chamber the next cartridge
    ... as illustrated, while the fired cartridge is being extracted the rotary piston is rotating the piston dish and feeding arm past the point where they will be usable for to lad the next cartridge.
    3) Once the piston dish has rotated..... what do you do with it now that the feed arm is out of position?

    Springs have already been mentioned, but that's a minor point if the mechanical linkages are good.
    Reciprocal to rotary and back works fine.. steam locomotives use it all the time. (Of course, they have both steam and vacuum to do the work of springs so it's hardly a fair comparison.)

    Lastly, I must add that the return spring for a paratrooper model FN FAL is not located in the folding buttstock, instead the mainspring is retained in a recess of a different bolt carrier, one without the usual 'rat tail'.
    Last edited: May 22, 2011
  10. 4thPointOfContact

    4thPointOfContact Well-Known Member

    Now... if you really want to come up with something both useful and inventive...
    Come up with a way to make an easily loaded magazine for a rifle that uses Dardick 'trounds'
    The revolving cylinder loads faster than inline and allows cooling as it cycles, but I can't think of any way to easily load trounds in a magazine that doesn't use feedlips.
    Tround, note equal-sided elliptical cartridges.

    Dardick feeding concept, note- no feedlips as the trounds slip sideways into the next chamber of the revolving cylinder.

    Actually... I can imagine a way, but it would feed like a P90 PDW and require a rotating piece.... hmmm....
  11. zollen

    zollen Well-Known Member

    Thanks for the inputs. Yes, my concept was inspired by piston internal combustion engine and stream powered locomotion. Let me think about everyone inputs and hopefully I will come up a better concept. I still think the circular concept is possible If I could work out the details. The main problem is durability, too many moving parts and everyone know there are plenty of simpler designs out there.
  12. Kliegl

    Kliegl member

    It's not a good idea. I mean, I'm all for you being creative and all, but this idea is not mechanically efficient. You are trying to apply a mechanical device to the wrong application, and are putting little things on it to make it work. The IC engine is the way it is because it takes expanding gases (like a gun) and turns them into shaft power (NOT like a gun.) The only reason the crank is there is to make shaft power. If you don't need any, don't make any.
  13. Sam Cade

    Sam Cade Member

    The main problem is that cartridge firearms are a simple, mature technology in which pretty much every reasonable way to stuff a cartridge into and yank it out of a chamber has been tried.

    There hasn't been any significant technological advancement in what constitutes state of the art in say, self-loading pistols in 100 years.

    Is a Glock (designed ca.1980 or so) significantly better than a 1911 whose design roots go back to 1900?

    A Glock is "better" in the sense that it is cheaper to make,tougher and has a longer service life but either tool in good repair will perform the same tasks.
  14. Sam Cade

    Sam Cade Member

    H&R apparently gave this a go.

    Attached Files:

  15. zollen

    zollen Well-Known Member

    So.. you think it is possible to utilize Dardick trounds for replacing the standard AR Reciprocating shell extraction and shell feeding. Thereby eliminating the need of gas tube, gas block, buffer tube, BCG and springs all together.

    I am not sure I understand what is the difficulty of loading trounds rounds into a magazine.

    Here is what I think it could be done...

    Imagine a standard AR magazine that could be loaded elliptical cartridges from the bottom (instead of from the top). A user would hold such a magazine upside down, then open the bottom cover, and just 'pour' elliptical cartridges into a magazine until the magazine is full. Then finally a user would manually rotate the cylinder (which is part of the magazine) to properly load the cartridges in the cylinder's empty chambers.
    Last edited: May 22, 2011
  16. Sam Cade

    Sam Cade Member

    In short, NO. You still have to power the cylinder turning.

    ...anyway, the Dardick failed for a reason:
    It was inferior to other already extant designs.
  17. zollen

    zollen Well-Known Member

    True. It does not change the fact that the conventional design of BCG and buffer tube would be no longer needed. It would still need gas block, gas tube and a new design of a firing pin and springs.
  18. Jim Watson

    Jim Watson Well-Known Member

    There was an open chamber machine gun running Trounds, the HiVAP. But it was a rotary with external motor, not self actuating.
  19. Sam Cade

    Sam Cade Member

    ...and a way to time the thing to keep it locked/unlocked at the right times.

    So.... you a mechanical engineer or a machinist? :uhoh:
  20. deadin

    deadin Well-Known Member

    Here's another concept called a "split breech" that has been worked on several times since a Fokker design during WW1. The idea is to do away with linear motion all together. (The Dardick falls into this category.)

    http://www.quarry.nildram.co.uk/Split Breech.htm

Share This Page