MK148 ADCAP RC Electric Torpedo

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  • trout
    Admiral
    • Jul 2011
    • 3545

    #16
    Looking at his drawing and photos, it looks like it will already be nose up - that is my guess from what I have done already. Manfred is right on level trim. In my video you will see the torpedo hit the curve of the test pool and dive. It does eventually raise up, but in that time it can snag on weeds or rocks.
    If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

    Comment

    • Scott T
      Commander
      • May 2009
      • 378

      #17
      Click image for larger version  Name:	IMG_20200310_182420 (2).jpg Views:	0 Size:	85.2 KB ID:	137148
      An idea for a coupling between prop shaft and motor shaft is to use heat shrink.
      Slide it on shrink a little at both ends to shafts. Add superglue if needed.
      Last edited by Scott T; 03-13-2020, 01:08 PM.

      Comment

      • MFR1964
        Detail Nut of the First Order
        • Sep 2010
        • 1290

        #18
        Originally posted by Scott T
        An idea for a coupling between prop shaft and motor shaft is to use heat shrink.
        Slide it on shrink a little at both ends to shafts. Add superglue if needed.
        That won't work, use some silicone hose, that piece of heat shrink is not flexible enough.

        As for getting the shaft sealed, i use vaseline as lubricant inside a chamber, which is located inside the rear-end, this is enough protection for running at the surface, if
        you want to run deeper use O rings for both the shaft and sealing of the body of your torp.

        Some tips for building the launcher,

        1 take a tube size which is roomy enough to house your torp, snugg fitt is a no go, you need that room to surround the torp in water.
        2 make enough slits into your launchertube, mine have slits on the sides, underneath and above, once again this is done to let the water inside the launchtube, whit less or no slits the torp will not exit the launchtube.
        3 as for pushing out the torp i've been using a small spring, launching happens pretty much the same way as those springloaded toyguns.
        My nextgeneration tubes are free launchers, no springs used, i simply let the torp launch itself out of the tube, a KISS solution, the activation magnet is placed on a rod which is connected to the servo, you can lock the torp by using that ball lock David has used on the gaslaunchers.

        Manfred.

        I went underground

        Comment

        • QuarterMaster
          Rear Admiral
          • Sep 2015
          • 1194

          #19
          Sorry guy's.....

          I was describing how it's done, not asking for help. But I do enjoy the discussion.

          I AM not sealing the end, I am doing what I described and filling with CorrosionX, less viscous and easily replaceable than Vaseline, which WILL hold fine debris. Also these fish are $10.50 USD each (which includes the 3D print material) To me that's cheaper than most of you spending on your first craft beer of the evening. Bet dollars to donuts of these they last at least two seasons, making 'em cheaper than a latte per season, but don't really care if they don't, I don't drink alcohol.

          Water WILL NOT GET PAST THE MOTOR to the important stuff.

          My keel depth is on the order of 18 inches, I am not wasting time with orings either. I'm a happy 2.4Ghz sailor.

          Originally posted by Scott T
          Click image for larger version Name:	IMG_20200310_182420 (2).jpg Views:	0 Size:	85.2 KB ID:	137148
          An idea for a coupling between prop shaft and motor shaft is to use heat shrink.
          Slide it on shrink a little at both ends to shafts. Add superglue if needed.
          I bought 8 pairs of LH/RH RC Drone propellers for $8

          Using the spare hubs from the opposite pitch prop as shown in the photo on .03 dia rod works JUST fine. I would toss them out anyway. NO need to think further...period.

          Originally posted by MFR1964
          As for getting the shaft sealed, i use vaseline as lubricant inside a chamber, which is located inside the rear-end, this is enough protection for running at the surface, if
          you want to run deeper use O rings for both the shaft and sealing of the body of your torp.

          Some tips for building the launcher,

          1 take a tube size which is roomy enough to house your torp, snugg fitt is a no go, you need that room to surround the torp in water.
          2 make enough slits into your launchertube, mine have slits on the sides, underneath and above, once again this is done to let the water inside the launchtube, whit less or no slits the torp will not exit the launchtube.
          3 as for pushing out the torp i've been using a small spring, launching happens pretty much the same way as those springloaded toyguns.
          My nextgeneration tubes are free launchers, no springs used, i simply let the torp launch itself out of the tube, a KISS solution, the activation magnet is placed on a rod which is connected to the servo, you can lock the torp by using that ball lock David has used on the gaslaunchers.

          Manfred.
          Nope, I already described how I'm doing it, go read the first post, THAT is KISS. A rubber band plunger will impulse the fish out with the very fluid it's in. SIMPLE and not losing energy to accelerate.

          Excuse the crude drawing, I will have the prototype operational next week and will demonstrate in a video.

          Click image for larger version  Name:	IMG_20200313_175612.jpg Views:	0 Size:	90.1 KB ID:	137154

          Here are the existing Tubes on the SHARK, Imagine those brass tubes as a Plexiglas rod. the port side simulating the plunger cocked and ready to fire. The servo pulls the catch, the plunger is pulled forward by a rubber band, which pushes the water in front of THAT forward, which forces the fish past the switch magnet and out the tube. The kinetic energy of the launch saves on the stored 22.5 joules in the super-cap. She will be refitted with the MK113/RB by April, need to relocate that yellow power box. Granted it's longer than a gas ejection, but 1:48 scale gives me the room for this. APPLICATION....APPLICATION....APPLICATION.

          Click image for larger version  Name:	IMG_20200313_175709.jpg Views:	0 Size:	38.5 KB ID:	137155

          In regards to your earlier post these fish are positively buoyant and WILL NOT run aground. As for losing them anyway, who the heck shoots them in any direction but back towards the observer to land them on the shore anyway? Track your target for a firing solution to have him between you and your boat lol. I'm building a Springer Class retrieval tug to fetch errant fish.

          Tell me that's not simple...I double dog dare you.


          Again very interesting discussion, but this is the course I'm following. NO need to change the engineering model, but thanks!

          (Yes Dave, I'll agree the yellow cigarette box is "tupperware"....any port in a storm!)

          v/r "Sub" Ed

          Silent Service "Cold War" Veteran (The good years!)
          NEVER underestimate the power of a Sailor who served aboard a submarine.
          USS ULYSSES S GRANT-USS SHARK-USS NAUTILUS-USS KEY WEST-USS BLUEBACK-USS PATRICK HENRY-K432-U25-SSRN SEAVIEW-PROTEUS-NAUTILUS

          Comment

          • MFR1964
            Detail Nut of the First Order
            • Sep 2010
            • 1290

            #20
            Yet again, interesting to see how your launchsystem will turn out, i'm allways on the watch to see something new to be born.

            Manfred.
            I went underground

            Comment

            • Bob Gato
              Captain
              • Feb 2019
              • 826

              #21
              So here's my latest take-
              Rather then canted fins to counteract a spin , which add only drag and possibly a turning vector-Another avenue of approach would be counter-rotating props-and since this is not practical, my I idea would be to attach a reverse pitch prop to the tail cone and have the shaft free run thru it to drive the main prop-then just let the torpedo spin as it goes forward...Both props would impart forward thrust ..

              Comment

              • Bob Gato
                Captain
                • Feb 2019
                • 826

                #22
                I have not tried the static second propeller yet but in testing I have determined that the curved track (as noted and mentioned by Bob M) with a lot of prop driven mini torpedoes is not so much from canted fins..it appears to be from prop torque (prop walk) I have tried both CW and CCW props and CW (looking FWD) prop pushes the aft end of the torp to the right causing the torp to curve to the left and the reverse for CCW prop. Now this was with a two bladed prop-possibly a three blade prop wont walk so much...

                Comment

                • He Who Shall Not Be Named
                  Moderator
                  • Aug 2008
                  • 12253

                  #23
                  Originally posted by Bob Gato
                  So here's my latest take-
                  Rather then canted fins to counteract a spin , which add only drag and possibly a turning vector-Another avenue of approach would be counter-rotating props-and since this is not practical, my I idea would be to attach a reverse pitch prop to the tail cone and have the shaft free run thru it to drive the main prop-then just let the torpedo spin as it goes forward...Both props would impart forward thrust ..
                  Put that 'fixed prop' at a near zero pitch (or small fraction of the propeller pitch) and you have a stator. Then wrap a tapered shroud about the two and you have a MK 48 propulsor.

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                  David
                  Last edited by He Who Shall Not Be Named; 03-30-2020, 10:22 AM.
                  Who is John Galt?

                  Comment

                  • Bob Gato
                    Captain
                    • Feb 2019
                    • 826

                    #24
                    That would probably fix all the issues-but I am working with a 1/64th scale-the prop is fastly approaching the too small to be operational size and if I reduce diameter any more to fit a shroud around around it ( and still have it fit in a 7/16 torpedo tube) I am afraid that it will not provide thrust...this is where I envy the 1/48ths

                    Comment

                    • He Who Shall Not Be Named
                      Moderator
                      • Aug 2008
                      • 12253

                      #25
                      Originally posted by Bob Gato
                      That would probably fix all the issues-but I am working with a 1/64th scale-the prop is fastly approaching the too small to be operational size and if I reduce diameter any more to fit a shroud around around it ( and still have it fit in a 7/16 torpedo tube) I am afraid that it will not provide thrust...this is where I envy the 1/48ths
                      These weapons are 1/96 scale. MK48 torpedo, with shroud, is third from right. Click image for larger version

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                      David
                      Who is John Galt?

                      Comment

                      • Bob Gato
                        Captain
                        • Feb 2019
                        • 826

                        #26
                        Wow -Nice! aren't those gas torpedoes? I am impressed- If they are electric -I am VERY impressed! (I am trying electrics)

                        Comment

                        • He Who Shall Not Be Named
                          Moderator
                          • Aug 2008
                          • 12253

                          #27
                          Originally posted by Bob Gato
                          Wow -Nice! aren't those gas torpedoes? I am impressed- If they are electric -I am VERY impressed! (I am trying electrics)
                          Nope. Just run-of-the-mill, anyone-can-do-it, simple gas propelled weapons. Hardly worth mentioning.

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                          David
                          Last edited by He Who Shall Not Be Named; 03-30-2020, 03:11 PM.
                          Who is John Galt?

                          Comment

                          • trout
                            Admiral
                            • Jul 2011
                            • 3545

                            #28
                            That display is a work of art! How cool is that? Very.
                            If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                            Comment

                            • He Who Shall Not Be Named
                              Moderator
                              • Aug 2008
                              • 12253

                              #29
                              An aspect of professional model building is the ability (and willingness) to build whatever the client wants -- we did some display work for defense contractors, some of our work for that profession even made it to the second floor of the Smithsonian Air & Space museum for a couple of years. The Torpedo Launcher Demonstrator was an in-house project, but encompassed some of the tricks I learned working for the 'big-boys'.

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                              David
                              Who is John Galt?

                              Comment

                              • OleToothless
                                Ensign
                                • Oct 2017
                                • 2

                                #30
                                Fantastic stuff, the torpedo looks great. If the first batch ends up with a lot of curvature in the shot-path, just remember that circular runs were a real problem! Perhaps it would be possible (on a future batch) to 3D print a miniature pump-jet style propulsor on that scale, with the propeller separate from but captive within the outer shroud.

                                How does the nose (+) charging pin work? What is it in contact with? From your sketch it looks like it is in contact with the torpedo tube door, but I don't see any actuators to open/close the doors on your picture of the USS Shark. Or maybe I'm over-thinking it and the tube stay open and the torpedo is charged when the sub is out of the water via an alligator clip or something?


                                HWSNBN - that torpedo display is a wonder. All of the details, the placement of each part... it's very specific, diligent. Amazing stuff.


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