Cooling the motors?

[rpm]

I guess my point is

I guess my point is if done correctly with a matched setup water cooling is not needed at all.

[rpm]

I see that there is

I see that there is no edit feature here.

Speaking of water cooling if there is ANY component you want to water cool it's the ESC.

[tmsmalley]

I see there is no

I see there is no edit feature here.

The edit feature becomes active when you sign up (as a SubCommittee member) with the webmaster.

[john_h]

Probably there is a mathematical

Probably there is a mathematical answer to my question, or a formal way to arrive at a "best guess." You can alter the number of winds, number of poles, gear ratios, props size and pitch, and pulse width modulation on the way to perfecting the drive. It has the look of an optimization problem.

But the props for the USS Katahdin steam ram were chosen for near-scale appearance, which is probably the worst way to go about it from an engineering standpoint.

It was a ram, and the prototype was built to go fast. What first interested me about the USS Katahdin as a subject for a model was the idea that it would probably look very interesting surging through the water.

But we know from thermodynamics that the motor system and associated electronics is going to make heat, entropy. Even in a perfectly optimized system, heat will arise.

It is probably an embellishment to try to get rid of it, but I just think the machine is happier running cool. And in a moving boat, cooling water is easy to come by.

The fast electric community seems far gone on water cooling, and they have a lot of hardware photos and discussion up on the net about it. This photo impressed me -- a system which cools the brushes as well as the can.

http://www.mmeu.com/images/ken_jo6.jpg

It may be that as brushless motors become more popular, the problem will change. In electric aircraft, high torque brushless motors have recently made it possible to drop gearboxes and still swing big propellors.






http://www.mmeu.com/images/ken_jo6.jpg

[Guest]

Can even wind your own

Can even wind your own brushless-

http://www.gobrushless.com

Andy

[john_h]

I am going to follow

I am going to follow the example suggested by BigDave, who watercooled his Nautilus. Brushless is the future, but I am already committed to a pair of ESC's and a mixer intended for brushed motors. And I have the motors. As for the gearing, I will try direct, and if it doesn't work, I will gear down. Many thanks for your thoughtful insights. I will post a photo of the installation as things progress...

Incidentally, and I will post this as a new topic at some point -- I need airbrush painting help. If someone has the skills and equipment to do a fine airbrush paint job on this model, or if you know someone who does, I would like to commission the job. It would be helpful if you lived within a day's drive of NYC. It is two colors, about 48 inches long.

At present the model is olive drab, a prime coat. The prototype was painted sea green. Here is what it looked like in 1898.

http://www.grovestreet.com/jsp/onepic.jsp?id=487561

[lundberg]

Hi,

just wanted to mention that

Hi,

just wanted to mention that I'm using a watercooled speedcontroller on my Nautilus, it's a Robbe Navy...

The motor itself is not cooled, its a geared down Robbe motor.

/Bjorn

[rpm]

John, Thats a pretty neat

John, Thats a pretty neat boat, I'd love to airbrush it for you but I am across the country

Yes in a very small compartment water cooling would be good.

Kyosho makes a very neat water cooled brush holder for their motors. Not cheap but is pretty cool.

[Guest]

I've never found it necessary

I've never found it necessary to watercool my ESC.

The FET's used in modern designs are so tough and highly rated, current wise, that it's almost impossible to cook them in conventional modelling applications.

The controllers I use in my models are thermally protected, so will shut down if overheated. However I've never experienced this in practice.

Andy



Edited By Sub culture on 1091957188

[safrole]

I have an ESC from

I have an ESC from Subconcepts made with FETs and even when my motors are quite hot there is very little heat in the ESC.