FX Crown Bespoke Moderator – Tesla Gas Diode

Forums PCP Airguns FX Crown Bespoke Moderator – Tesla Gas Diode

  • Views : 497
  • Link

    STO
    Participant
    Member

    Decided to try out an idea I've had for a while: design a Tesla Gas Diode around an airgun moderator. The basic principle of Tesla's is to reflex the gas back on itself to limit flow in one direction, but permit it in the other. Given that the Crown comes with a shroud and brake (essentially a blast baffle) I figured I'd make the whole moderator bespoke to work with this. So it also taps off air and sends it through an outside set of channels which spin and disrupt and quiet it. Put the whole thing in light weight carbon fiber shell, and add a few glow-in-the-dark blue rings at the front and back. The whole thing is super short and light at just 120mm and 64 grams. No reduction in accuracy whatsoever, still easily sub MOA at 100 yards, which is the most important part. Pictures tell the story. 

    • This topic was modified 1 week ago by STO.
    Link

    2D1C
    Participant
    Member

    Cool stuff right there! Lets know how it works.

    Link

    SocalTrail
    Participant
    Member

    Nice!  I’m assuming it’s 3D printed?  Do you have any other mods to compare it to like a Huggett or Donny FL??

    Link

    Macros
    Participant
    Member

    Wow that looks amazing! So nice to see some innovative thinking in silencers. Usually they're basically all hair curlers and washer baffles 😋

    How's the sound reduction? What you were hoping for? Better?

    Link

    gunsnknives
    Participant
    Member

    Fascinating. Thanks for sharing. How is the sound reduction? What is it made of? 

    Link

    Cranky1
    Participant
    Member

    Beautiful design. Hopefully it works as good as it looks. 

    Link

    PumaCarl
    Participant
    Member

      NICE! Very nice. Please post some numbers compared to a DonnyFL anything. I've been getting bored and I do believe a 3D printer is in my immediate future.

    Link

    STO
    Participant
    Member

    Many questions. Alrighty, let me see if I can answer them. 

    How does it work? Subjectively, to my ear anyway, it works very well taking the bark off the Crown. It also has good tone, not producing the shrill sounds of some silencer designs. That said, I don't have anything directly to compare it to. In a long long time ago in a galaxy far far away I was actually an engineer doing design work on firearm silencers for a company. Experience tells me small differences in both design and host can make big differences in sound, but also that the human ear is a pretty bad judge of sound intensity. My closest comparison is a mostly foam filled moderator of the same diameter and roughly the same length on my Air Arms S510. To my ear and with a sound reflective surface in front of me to send some muzzle sound back, disclaimer now stated, it sounds quieter than that. It isn't a fair comparison by any means, but it is what I have. 

    I don't have a DonnyFL or Hugget, but quite frankly it isn't really that interesting to me to compare it to one. Both of those designs use pretty simple architecture, a chamber or two and some high surface area material like a wool or foam. Small differences in the material of the can and design of the caps could make them meter very differently (for better or for worse), not to mention overall size. My plan therefore is to build another suppressor design of a style similar to the felt/foam filled ones. I also want to try out a common firearms industry suppressor design, the clipped conical baffle. All of this to see if the gas diode concept has merit in this application. That is what I'm genuinely curious about. I've wanted to try it out for years, and now I finally can. It'll take me some time, but once I have all the different suppressor designs I want to compare it to, I'll dig up the old impulse sound meter, which can actually accurately compare things like gunshots unlike my ear, and quantify it. 

    What is it made of? The tube is obviously carbon fiber. The core is 3D printed from ABS. I've printed other moderator designs from this, and it works great probably due in part to ABS' good impact resistance. I realize I posted the images in black and white, but I did the core on this one out of a metallic copper ABS with blue glow in the dark accents. I could do polycarbonate, an extreme PC alloy, 20% carbon filled nylon or polycarb, etc but I've never found in necessary on an airgun. *shrug* gunsnknives

    Fascinating. Thanks for sharing. How is the sound reduction? What is it made of? 

     

    Macros

    Wow that looks amazing! So nice to see some innovative thinking in silencers. Usually they're basically all hair curlers and washer baffles 😋

    How's the sound reduction? What you were hoping for? Better?

    That last one really is a great way to parse the question, and I want to hover over that for a second. Expectations matter. This moderator is smaller than a DonnyFL tanto. A whisker larger diameter, and about half an inch shorter. It is also half the weight. These things matter because volume, length, and mass all work to deaden sound. I bring this up because my goal was small, light, and accurate not complete and absolute silence. Suppressor designs also are capable of generating internal cross-jetting. You can make this very aggressive to make your design quieter, however it comes at the cost of accuracy and POI shift. Pellets are extremely sensitive to it, and easy to destabilize. I suspect this is why a lot of airgun moderators often have simple designs, hair curlers and washer baffles as you put it, because if you generate too much internal turbulence or cross-jetting your accuracy will to go pot. 

     

    I hope that answered everyone's questions. Since people seem interested, I'll keep posting updates as they come. :) 

    Link

    cosmic
    Participant
    Member

    Very COOL !!!

    Link

    STO
    Participant
    Member

    stoti check your private message inbox. 

    Link

    Macros
    Participant
    Member

    Brilliant – thanks for your answer 👍🏻

    Illuminating point you made about the cross jetting. Explains things with a few silencers I've tried, that just ruin accuracy without a hint of clipping.

    I'll be following your progress with great interest!

    Cheers!

    Link

    BlackICE
    Participant
    Member

    To minimize cross jetting affecting the pellet would a 1st chamber without cross jetting reduce the air pressure and air velocity so that the pellet may out run the gas turbulence in later chambers with cross jetting? I think this would be effective when used in conjunction with a shrouded barrel that the gas can be redirected to from the 1st chamber.

     

     

    Link

    Nutcracker
    Participant
    Member

    Interesting read 4am when you can't sleep.  Will be following this. Thanks for sharing. 

    Link

    STO
    Participant
    Member

    BlackICE

    To minimize cross jetting affecting the pellet would a 1st chamber without cross jetting reduce the air pressure and air velocity so that the pellet may out run the gas turbulence in later chambers with cross jetting? I think this would be effective when used in conjunction with a shrouded barrel that the gas can be redirected to from the 1st chamber.

     

     

    Yes, which is why you often see symmetrical blast baffles, at least in firearm suppressor designs. Take the Silencerco Osprey as probably the most famous example:

    It doesn't completely mitigate it, of course, but it can take the edge off. The Crown you'll note already essentially has this, as it has its own "blast baffle" inside the shroud, and then you could consider the rear face of the moderator itself a second flat blast baffle which should induce no significant asymmetric cross-flow. For reasons of stacking tolerances on the concentricity though, the integral blast baffle is probably the more effective air stripper as I'd expect it to have a tighter tolerance to the pellet. 

     

    Macros

    Brilliant – thanks for your answer 👍🏻

    Illuminating point you made about the cross jetting. Explains things with a few silencers I've tried, that just ruin accuracy without a hint of clipping.

    I'll be following your progress with great interest!

    Cheers!

    Yup, been there too. Worst I can remember, airgun-wise anyway, was a cross-flow K-baffle design I purchased ages ago. Really opened up the groups substantially, to the point where you couldn't really call them groups anymore. Sort of an area-effect kind of thing. :P The design was also shrill as hell. 

    Link

    Macros
    Participant
    Member

    Lol 😂 

    Link

    Macros
    Participant
    Member

    How is the silencer doing?

    Link

    STO
    Participant
    Member

    Macros

    How is the silencer doing?

    It is going. I've got the flow-through clipped-conical-baffle design done and a little initial testing. Very interesting results there. The foam/felt analogue is the only one which remains. I have it all designed, most of it printed and the carbon cut, but I still have to laser out whatever high-surface-area material I'm going to use. Since long term durability isn't an issue, it is just a test mule after all, I have some medium density open cell carbon foam I'll probably use. I've used the same stuff in other moderators I've built and it works very well at sound deadening, but unless constrained has a habit of eventually pulling itself into the pellet path. *shrug* 

     

    The original one though, the actual gas diode concept, is still living on my gun. It has picked up a fair bit of lead dust at the basal end. It has seen a couple tins of pellets now, and still works like a champ. I'm very happy with it. 

Viewing 17 posts - 1 through 17 (of 17 total)

You must be logged in to reply to this topic.