Heat Buildup

[severstal81]

I've been into RC subs for a few years but have just recently gotten around to building my first sub and my friend (an RC plane guy) had a great question the other day. Is there any need to deal with heat buildup in an rc submarine? I've researched rc subs for a long time but I'd never heard any mention of heat problems.

[Slats]

In my experience - provided you don't have any binding of shafts / push rods etc, heat really is not a big problem.
Things that can get hot are linear type voltage regulators / BECs, but these do not cause a problem for the surrounding gear.
Expect you motor(s) to get warm - if you do the right thing you'll (no binding) and are using a gear box, don't expect the motor to hot up like an RC car or plane.

If you're building your first sub, avoid building your own WTC, buy a Sub-driver. Its cost effective, you'll learn heaps, you'll have backup by the manufacturer, and your time spent behind the transmitter having fun will be maximised.

Good luck
John

[redboat219]

Go over Aquasubs' thread. He has some motor cooling ideas you could use.
http://forum.sub-driver.com/showthre...ws-To-The-Yard!!

[severstal81]

I have a Dumas Bluefish and it has the shafts directly connected to the motors. The motors are only 4.8V but do you think I should mod it slightly and add a gear box?

Thanks!
Morgan

[Slats]

Try it first and see how it goes.

If you buy a subdriver later on the motor comes in most cases with a gearbox already installed.

Unlike model boats, subs don't get driven everywhere at flank bell - you'll probably be fine with the stock approach from Dumas being ok as a first up boat. If you do get some heat build up that is of concern you could always add a small heat sink to the motor casing.

I take it's a dynamic diver (no ballast tank)? Nothing wrong with these as a good starter.

Be sure to post your assembly here so we can all take a look. I am sure you will be fine.

Best
John

[Albion]

I have a Dumas Bluefish and it has the shafts directly connected to the motors. The motors are only 4.8V but do you think I should mod it slightly and add a gear box?

Thanks!
Morgan

Are you able to drive the props in water and measure amps? Ask yourself are the amps high for the size and type of motors , and do the motors sound like they are straining. If yes then maybe gearbox would work, or try replacing them with a lower reving motor. I recenlty rebuilt one of my boats and tried a differnet motor. i thought it was same speed, but was much faster, so it was pulling high amps and could be heard straining under the load.

[Kazzer]

Are you able to drive the props in water and measure amps?

His Impertinence has explained to me that the ultimate test for a motor is to rig it up with a multimeter and battery, get it running at full speed, and clamp pliers etc. onto the shaft to actually stall the motor. Then read the current draw on the stalled motor. This way, you can be assured that the ESC is rated adequately.

[Albion]

I knew I read it somewhere, yes I did that too. I figured on the Permit that with 7.5Amps on load and the motor making a strained noise that the stall was going to be too high, it was already connected to a 10amp ESC :(
I changed to lower speed 540 and it now pulls 2 Amps at full load, 4 amps stalled. Simple!