Planetary Gear Box's

[QuarterMaster]

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.

[SubDude]

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".

[QuarterMaster]

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: 17k 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?