New Prop design?

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  • trout
    Admiral
    • Jul 2011
    • 3545

    New Prop design?

    A interesting article....not that we are trying to make our propellors quieter, but maybe efficiency may extend our batteries? (Like running 2+ hours is not long enough LOL)
    https://newatlas.com/aircraft/toroidal-quiet-propellers
    If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.
  • JHapprich
    Captain
    • Oct 2017
    • 715

    #2
    Incredible!

    Comment

    • Bob Gato
      Captain
      • Feb 2019
      • 826

      #3
      These are truly game changers- I find it interesting that 2.4 GHz RC radios were made cost effective by the drone world...and more interesting that a guy named Sharrow was trying to quiet down his drone so he could video an outdoor orchestra...again the drone world!

      -when they were invented, they were deemed too expensive to manufacture (they were just about impossible to machine). Now being able to 3D print stainless, plastic, bronze or aluminum they are totally doable

      .https://www.youtube.com/watch?v=MNnB_50Z20I


      I am sure that you will not SEE them on submarines (wink emoji)
      Last edited by Bob Gato; 01-29-2023, 09:22 AM.

      Comment

      • rwtdiver
        Vice Admiral
        • Feb 2019
        • 1770

        #4
        Originally posted by Bob Gato
        These are truly game changers- I find it interesting that 2.4 GHz RC radios were made cost effective by the drone world...and more interesting that a guy named Sharrow was trying to quiet down his drone so he could video an outdoor orchestra...again the drone world!

        -when they were invented, they were deemed too expensive to manufacture (they were just about impossible to machine). Now being able to 3D print stainless, plastic, bronze or aluminum they are totally doable

        .https://www.youtube.com/watch?v=MNnB_50Z20I


        I am sure that you will not SEE them on submarines (wink emoji)
        Hi Bob,

        It may not be true to scale, but it might be interesting to try it on a Submarine! :-)) Interesting information for sure!

        Rob
        "Firemen can stand the heat."

        Comment

        • Bob Gato
          Captain
          • Feb 2019
          • 826

          #5
          .. this is a military secret that never had a chance to become secret. That last line in my post was referencing my suspicion that the US government is looking in to these toroidal propellers because of their extreme reduction of blade tip vortices and the resulting quietness of this design... But if that is the case it'll be at least 10 years before anybody ever sees one hanging off the back end of a nuke sub.... I'm sorry to say the cat is out of the bag as a result of the private sector coming up with this radical design... Yes I would also love to see one tried on a model sub...

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          • RCSubGuy
            Welcome to my underwater realm!
            • Aug 2009
            • 1768

            #6
            If my 3D modeling chops were stronger, I'd take a stab at this in a heartbeat. It would be cool to see on a concept sub of some kind. They look futuristic enough to fit in....

            Comment

            • CC Clarke
              Lieutenant Commander
              • Aug 2020
              • 239

              #7
              You can get started on Thingverse. Just enter "Sharrow" in the search field.

              CC

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              • Bob Gato
                Captain
                • Feb 2019
                • 826

                #8
                I could be oversimplifying this... But it appears to me that if you took two of the same brass propellers, shortened their hubs and stacked them one on top of the other, bent/curled the blade tips until they touched taking care to preserve the pitch angles and then silver braze the tips and the hubs together, you would have something similar.
                I could give it a go when I get back in a week or so... "Going to the beach" and my kids are turning my house into "party Central"

                To quote a Jimmy Buffett song title... "Gypsies in the Palace"
                Last edited by Bob Gato; 01-30-2023, 05:12 PM.

                Comment

                • JHapprich
                  Captain
                  • Oct 2017
                  • 715

                  #9
                  Give it a try!
                  and when youre done, ill patch it onto the beluga a go scaring the ducks!

                  Comment

                  • CC Clarke
                    Lieutenant Commander
                    • Aug 2020
                    • 239

                    #10
                    I changed the number of blades from 3 to 5, 6 and 7 and rendered these for comparison purposes. Haven't designed a proper shroud yet, but these have potential. Too bad my plate is full or I'd have fun changing the sweep angle and measuring the thrust.

                    That's the beauty of 3D design; you can build an object, print it in high-temp wax resin, and create molds (moulds for our cousins across the pond) or take the shortcut and print them in high strength resin for test purposes. If it doesn't work out, change and test again. Very efficient over trying to hand-build something like this with unpredictable results, unless time is irrelevant.


                    Not sure how these would work in the real submarine world with wake detectors becoming more tactically relevant. The US had them at one point and moved on. The Russians have used them for a long time and the Brits like them too.

                    All are modeled with a 40mm diameter and 4mm shaft.

                    CC

                    Click image for larger version

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                    • RCSubGuy
                      Welcome to my underwater realm!
                      • Aug 2009
                      • 1768

                      #11
                      Like CC Clark pointed out, Sharrow makes these and has for a long time for outboard motors. They advertise an increase of 50% power in reverse, increased mid-throttle power, and other benefits. That said, I just watched a video of a guy that replaced a computer heat fan with this prop design and he saw a reduction in performance over stock (pushing air, of course) and only a slight decrease in high frequency noise.

                      The big advantage to these is noise level. In our RC subs, that is not a relevant performance criteria, so replacing a stock prop with one of these would have to be done solely for replication of a full-sized boat (which we haven't seen yet), or just to say you did it.

                      Bob

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