Planetary Gear Box's

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  • QuarterMaster
    Rear Admiral
    • Sep 2015
    • 1198

    Planetary Gear Box's

    ALCON,

    At that last Dive Tribe meeting there was discussion regarding gear reduction to help with poor low end performance with respect to Brushless motors.

    IE: 1​7k No Load RPM @ WOT Motor output reduced 3.8:1 now outputs 4473 RPM WOT/NL on the output shaft. The throttle range is greatly reduced assisting with that "stutter" experienced at throttle start.

    I found these in the past. Though made for brush Speed 400/480/500/600 Motors, they can be adapted to brushless with a little effort.

    MP Jet​

    Anyone out here have any other resources or know of vendors for Inline Planetary Gearboxes for brushless motors?
    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
  • SubDude
    Captain
    • Dec 2019
    • 803

    #2
    Thanks for the good info. Ed. This is what I did on my Thresher. Motor/ESC is the Mtroniks G2 Hydra 50. 1400Kv so at 12 Vdc looking at roughly 15,000 rpms under load WOT. It was direct drive. Modified now with a spur gear (Axial p/n AX1232075) 60T/32P, pinion 15T/0.8 metric pitch which is equivalent to 32P. 4:1 ratio so turning around 3750 rpm WOT under load. Designed and 3D printed the spur gear center hub, drive shaft front support, servo mounts and ESC/cap bracket to replace the integrated part that the motor mount secured to. Spur gear center hub rides on a 10mm brass bushing I machined on my lathe that secures an M4 x 10mm set screw against the drive shaft so the set screw is long enough to extend into the 3D printed hub preventing it from rotating. The motor mount was from my original design and just so happened to fit with a thin shim under it. One minor benefit is that the motor is lower in the hull. Going to give it a try like this. May be a bit unconventional but I like to try new things. To use one of your phrases, "easy peasy lemon squeezy".

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    Last edited by SubDude; 04-23-2023, 07:51 PM.

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    • QuarterMaster
      Rear Admiral
      • Sep 2015
      • 1198

      #3
      I ran transmissions in the wet since Dave Merriman's WTC3.5 I got back in the day. Works like a charm other than the "Non-Silent" drive due to the water hammering with the gears meshing. Right Dave? lol!

      You don't need to see your boat coming by submerged, you'll hear it!

      I've done as high as 9:1 to get that slow speed, close by maneuvering and to avoid "jump starts". Broken many a dogbone back in the day.

      I know use the "Go Fast Boat" Shock absorber on all my large boats. I can slam into reverse on my 3-3/4" prop without fear of transmission breaking.

      Here is one on my ALFA which sports a 630KV, 534W rated "Quantum" Outrunner. I really had to dial down the endpoints due to inability to control the model (porpoising) above 50% throttle. The motor output shaft and screw shaft are only connected via 3/8"OD 1/8" thick o-rings.

      Conquest is easy, control is not
      Kirk, J.T. ST:TOS

      I am toying with using one of those very same MP Jet gearbox's downstream in it's own WTC (to eliminate water hammers). Maybe a good weekend project.


      Click image for larger version

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      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

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      • SubDude
        Captain
        • Dec 2019
        • 803

        #4
        Yes it will be somewhat noisy but we are not exactly trying to evade an enemy here.

        Comment

        • Subculture
          Admiral
          • Feb 2009
          • 2121

          #5
          Planetary gearboxes



          Also you can 3d print gears in herringbone pattern which are nice and quiet amd stronger than straight cut. Some designs on thingiverse used for gearing steppers etc. which could be adapted or grow your own using Fusion 360 gear generator.

          Comment

          • SubDude
            Captain
            • Dec 2019
            • 803

            #6
            Originally posted by Subculture
            Planetary gearboxes



            Also you can 3d print gears in herringbone pattern which are nice and quiet amd stronger than straight cut. Some designs on thingiverse used for gearing steppers etc. which could be adapted or grow your own using Fusion 360 gear generator.
            A free script called GF Gear Generator allows for creating all kinds of custom gears in Fusion 360 and yes there are quieter gears than plain spur gears. I may give that a try but I need to run it as is first to see if another gear type will be an improvement. It should be easy enough to swap out.

            Comment

            • Subculture
              Admiral
              • Feb 2009
              • 2121

              #7
              The set-up you have looks absolutely fine. A planetary gearbox is useful if space is tight.

              Any gear noise will be marginal from a single gear stage and much lower when running in the wet.

              Comment

              • He Who Shall Not Be Named
                Moderator
                • Aug 2008
                • 12287

                #8
                Running gear. A look back:

































                Who is John Galt?

                Comment

                • QuarterMaster
                  Rear Admiral
                  • Sep 2015
                  • 1198

                  #9
                  Originally posted by SubDude
                  Yes it will be somewhat noisy but we are not exactly trying to evade an enemy here.
                  True dat, lived with it for many years. That cylinder lived almost 15 years.


                  Of course there's the occasional query, "Ed' what's up with your reactor plant? Sounds Russian...."
                  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

                  • Schmitty1944
                    Lieutenant Commander
                    • Mar 2021
                    • 108

                    #10
                    Another source for planetary and offset gearbox's:



                    All features: dual ball bearings some include prop adapter sturdy metal construction some include multiple pinions motor sold separately some include prop adapter sturdy metal construction some include multiple pinions motor sold separatelyManual Part No. Gear Ratio Pinion Mounting Spacing Wt oz Shaft Dia Applications



                    Jason

                    Comment

                    • Sinksalot
                      Commander
                      • Mar 2020
                      • 332

                      #11
                      On my Engel Type IX, it came with a brushed motor geared setup. But we didnt like the geared system and went with two robbe 500kv brushless motors. The torq at low speed is great and it moves nice with no gearbox.

                      Click image for larger version

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                      Comment

                      • QuarterMaster
                        Rear Admiral
                        • Sep 2015
                        • 1198

                        #12
                        Originally posted by Sinksalot
                        On my Engel Type IX, it came with a brushed motor geared setup. But we didnt like the geared system and went with two robbe 500kv brushless motors. The torq at low speed is great and it moves nice with no gearbox.

                        Click image for larger version

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                        Will it soft start and rotate (at 1-2 click throttle) at such a speed you see the individual blades? Or does it jump right off with no low end?
                        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

                        • trout
                          Admiral
                          • Jul 2011
                          • 3547

                          #13
                          This is an oldie, but used a lot in older subs.......

                          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

                          • Sinksalot
                            Commander
                            • Mar 2020
                            • 332

                            #14
                            Originally posted by QuarterMaster

                            Will it soft start and rotate (at 1-2 click throttle) at such a speed you see the individual blades? Or does it jump right off with no low end?
                            I will try to make a recording of the speed of the props from 1% to 100%. But even at Subfest the props were able to move very slow to fast in a smooth way. You can see the props moving smooth and slow in the water in this video with those motors.



                            Comment

                            • QuarterMaster
                              Rear Admiral
                              • Sep 2015
                              • 1198

                              #15
                              Originally posted by Sinksalot

                              I will try to make a recording of the speed of the props from 1% to 100%. But even at Subfest the props were able to move very slow to fast in a smooth way. You can see the props moving smooth and slow in the water in this video with those motors.


                              Nice....

                              What onboard voltage to the ESC? SLA 6V, 12V, 2s Lipo, 3s Lipo?? Need to correspond that 500KV with the voltage range she's seeing.

                              I'm a big fan of Engel components.
                              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

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