Motor selection advice

[Thorbrandr]

While I am enjoying Wisconsin late season sub running, I am starting to setup for my winter builds. Maybe two builds this winter....

What is recommended for a motor for a propulsor drive modern sub - Columbia class in ~1/96 - driving a 70 mm 4 blade prop? Sub length will be abut 1.8m or ~6 ft

I am agnostic on brushed or brushless motors.

Thanks
T

[He Who Shall Not Be Named]

A 555 geared 3:1.

[Das Boot]

A 555 geared 3:1.

David,
what size drill bit did you use for the steel shaft/plastic gear assembly? It’s gotta be one tough drill bit as small as it is.

[He Who Shall Not Be Named]

David,
what size drill bit did you use for the steel shaft/plastic gear assembly? It’s gotta be one tough drill bit as small as it is.

1/16". Low speed, use oil.

[Subculture]

The 555’s come in a very wide range of winds, some low revving some really high, so be mindful which one you select. I suspect Dave is thinking about something like this one https://www.componentshop.co.uk/mabu...-dc-motor.html

At 3:1 reduction that would give an unloaded RPM of around 1700RPM at 12 volts, which sounds about right for your boat and prop combination.

A brushless equivalent would be a 28-35mm outrunner of around 350-400kv, with a similar reduction of 3:1.

[He Who Shall Not Be Named]

The 555’s come in a very wide range of winds, some low revving some really high, so be mindful which one you select. I suspect Dave is thinking about something like this one https://www.componentshop.co.uk/mabu...-dc-motor.html

At 3:1 reduction that would give an unloaded RPM of around 1700RPM at 12 volts, which sounds about right for your boat and prop combination.

A brushless equivalent would be a 28-35mm outrunner of around 350-400kv, with a similar reduction of 3:1.

On the array of typical motors we used commercially I not only counted the turns on each pole, I counted the poles, and measured the gauge of the armature wire.








But, here's the bottom line. Stop being so god-damned anal about the specifications of your motor. Just grab a motor, stick it in the drive-train, operate the boat in the water and determine if you're happy with it or not.

So, so many projects die on the vine because people, and I'm talking to you, overthink the project and never get off the ****ing toilet!

Slap the motor in place and FIND OUT!

David
Pragmatist

[Thorbrandr]

On the array of typical motors we used commercially I not only counted the turns on each pole, I counted the poles, and measured the gauge of the armature wire.

But, here's the bottom line. Stop being so god-damned anal about the specifications of your motor. Just grab a motor, stick it in the drive-train, operate the boat in the water and determine if you're happy with it or not.

So, so many projects die on the vine because people, and I'm talking to you, overthink the project and never get off the ****ing toilet!

Slap the motor in place and FIND OUT!

David
Pragmatist

t


Indeed! Looking at my other WTCs, there is a rather wide variation in the motors. Figured I would ask while I have the build going.

I am looking at my own WTC build for this one. I am already set for cutting and turning the plastic, and can print what I can't machine.

Chris

[Das Boot]

Motors are the thing that I have the least trouble with. I would order something off of Amazon, for the right size, and don’t worry about who makes it. Most of the stuff comes from China anyway, so they’re all about the same. To be quite honest, I have never had a motor failure. Electronics, electronic speed controllers, BEC, receivers, yes, but not a motor.