Japanese Class A 1/16

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

    Japanese Class A 1/16

    Ok Boys and Girls,

    I must be barking mad to do this, yes, i take the challence !!!, done some homework and brought the drawing to the copyshop, length will be around 1.37 mtr at scale 1/16.
    Want to build her from scratch, and make me some molds, if possible with weldindlines, rivets, etc, the tower will be build from sheet copper.
    But first some fun, last few days David and me were mailing around about this sub, he made the remark that we should take this conversation to the Forum, and fool that i'm i did!!!
    Have to upload some pics and a vid, be patient.

    Manfred.
    I went underground
  • He Who Shall Not Be Named
    Moderator
    • Aug 2008
    • 12255

    #2
    So! ... it begins!

    M
    Who is John Galt?

    Comment

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

      #3
      Like you allready know David, i made a "spinning" start.
      I'll fill in the story, i was very interested into Gene's magic gearbox, figured out how it worked and made a gearbox of my own, this happened a few days ago, got some very usefull information from David about using it in a wet enviroment.
      He explaned about running the gears as sloppy as possible, why?, it's all about fysics, you can't compress water, so a very small tolerance between the gear-teeth will grind you to a halt and mess up your gear.



      I decided to use a different approach, and took conical gears, this way you don't need that much parts, there is a catch, when building it up everything has to be in line, if you don't, you're going to loose some teeth.



      One of the testruns i made last evening, also did a test flooded with water, no difference, running smooth all the way, it's seems to be sloppy, but that's the intension.

      Later on the week i can catch up the enlarged drawings, i ordered two, one to cut in pieces, the other one for measurement and building up the master.

      Manfred.
      I went underground

      Comment

      • george
        Captain
        • Dec 2010
        • 727

        #4
        Hello Manfred

        Could you please post plans, specs. for your gearbox? I would like to try to build one, hopefully working like yours. Need it`s sizes as well please.

        Thanks
        George

        Comment

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

          #5
          George,

          I have no plans, no specs, just builded this freehand, used my experience to get this gearbox running, it's a one off, so no documentation either, by the way, i thought you were working on a Bronco Seehund 1:35?

          Manfred.
          I went underground

          Comment

          • Von Hilde
            Rear Admiral
            • Oct 2011
            • 1245

            #6
            OK Manfred, thats impressive. I like the simplicity with the pinion gears of your design. I have been fooling with the motor and mast section of a Venom helo which has counter rotation. Its rarher complex with two motors, but it gave me the idea of a two shaft single motor output, that I already have. only need one gear on each output shaft and a recpricle gear on the inner and outer shaft. Its not that complicated but I like your Idea better. My big question is, what your gear supply source? Also, if water is a problem with the gear tollerance, seal the box and fill with ATF. Small cap, tapped into a fill hole on the top plate. Like a full size transmission, you dont want to overfill. Leave some air space, for relief from expansion of the volume of fluid, due to some small heat that is generated. Viscosity changes but no pressure build up.
            Last edited by Von Hilde; 03-15-2015, 09:37 AM.

            Comment

            • He Who Shall Not Be Named
              Moderator
              • Aug 2008
              • 12255

              #7
              While attending Torpedoman A-school I learned that the counter-rotating propellers on the MK-37 family of torpedoes used a motor whose field winding assembly, as well as the armature, was free to rotate within the motor case. The after propeller was coupled to the armature, and the forward propeller was coupled to the field assembly. Not only does this arrangement eliminate the counter-rotation gear-box, but reduces noise, and assures perfect torque balancing so that net torque presented to the vehicle is a big, fat ZERO! Neat.

              I'm thinking of taking a motor, put the entire motor case on a bearing so the motor can rotate. Then it's a simple matter to couple the motor to the outer shaft (forward propeller), and drive the after propeller from the normal motor drive shaft. The motor would sit in the wet (good for one season, at least). Slip rings and brushes would get power to the rotating motor assembly.

              If I ever work out how to transfer a stock motor armature-commutator assembly onto a hollow shaft, then I would be able to use two motors in tandem -- The forward motor driving the after screw, the after motor driving the forward screw.

              Ah ... the posibilities!

              Click image for larger version

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              M
              Who is John Galt?

              Comment

              • Von Hilde
                Rear Admiral
                • Oct 2011
                • 1245

                #8
                Looks like an armature inside an armature here Click image for larger version

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                Comment

                • redboat219
                  Admiral
                  • Dec 2008
                  • 2735

                  #9
                  1/20 scale torpedo with counterrotating props
                  Make it simple, make strong, make it work!

                  Comment

                  • Von Hilde
                    Rear Admiral
                    • Oct 2011
                    • 1245

                    #10
                    Venom helo , 2 motor counter rotating shaft assemblyClick image for larger version

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ID:	97703I can replace the plastic outer shaft with brass tubing and replace the mainshaft with a longer rod, to suit the LOA to the hub carrage bearing at the cone.
                    Last edited by Von Hilde; 03-15-2015, 02:00 PM.

                    Comment

                    • He Who Shall Not Be Named
                      Moderator
                      • Aug 2008
                      • 12255

                      #11
                      Originally posted by redboat219
                      1/20 scale torpedo with counterrotating props
                      http://www.pt-boat.com/torpedo/torpedo.html
                      Good catch, Romel. I'll see if I can punch out a 555's motor-shaft. Film at eleven!

                      M
                      Who is John Galt?

                      Comment

                      • george
                        Captain
                        • Dec 2010
                        • 727

                        #12
                        Hi Manfred

                        The 1/35 Seehund is on hold till I see some ideas for a static WTC for it.

                        Since you have NO plans for your gearbox, could you show some up close pictures of it? What were the gear sizes and sources for the gears?

                        Thanks Again Manfred.

                        George

                        Comment

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

                          #13
                          Von,
                          I have no clue where they come from, just bought them in the local RC shop, i suspect he got them from Aeronaut, most of the his stuff is from that company.

                          Romel,

                          A good catch, i've seen this site before, but had lost the link to it, that guy uses two motors in tandem also a interesting way to get those props counter rotating.

                          David, go get them tiger!!!!!

                          George,

                          I guess they are about 1 cm in diameter, what i do know, you have to use two equal ones on both shafts, and use a different one at the center, the angle on the middle one is different compared to the outer ones.

                          And to please you guys more, i refurbished some rabousch props which i had in stock, and did some testing, all i can say, see for yourself.




                          Manfred.
                          Last edited by MFR1964; 03-15-2015, 03:10 PM.
                          I went underground

                          Comment

                          • redboat219
                            Admiral
                            • Dec 2008
                            • 2735

                            #14
                            just rwalized the correct term for this set up , it should be contra rotating props not counter rotating. Contra is used for 2 props on a single shaft turning in opposite directions, counter is 2 props on 2 different shafts turning in opposite directions.
                            Make it simple, make strong, make it work!

                            Comment

                            • Von Hilde
                              Rear Admiral
                              • Oct 2011
                              • 1245

                              #15
                              Originally posted by redboat219
                              just rwalized the correct term for this set up , it should be contra rotating props not counter rotating. Contra is used for 2 props on a single shaft turning in opposite directions, counter is 2 props on 2 different shafts turning in opposite directions.
                              Tecniclly you have two props on a centerline shaft in a shaft that rotate in opposite directions Its called LCT( limited to centerline thrust) so since you designed it you can call it anything you like. but it sure is cool. Your prototype gadjet could make a nice soufle' or crepe'. I should rip into my wife's, mother's old Hammelton Beach portable cake mixer for the gears inside there.

                              Comment

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