Yes My motors do go in rev. No my motors dont have water cooling on them, they get warm but not to a temp where you can touch them. Nor are my ESC water cooled but it is fitted if I needed to .

HI Thom
To my knowledge all brushless motor will reverse, it's the esc that gives you that function
Dave

HI Bill,

Thank you very much for the input. I've just tested my brushed motors again, with no obvious resistance in the shafts, and they're still overheating, which leads me to believe that Mark hit the nail on the head with his first post - these motors are not appropriate for this model.

Just curious - the motors you have - will they do reverse?

Do the motors you have require any type of cooling at all?

I really appreciate all the input I've received - hopefully I will have some motors in this model shortly which will maintain the speed I want without overheating.

Thom

HI Ive just been taking a look at this posting. Don't mess about with brush motors! I have fitted to my Slipway Tamar 2 Turnigy 1250Kv brushless motors, Hobbyking 50amp ESC and two 5 maH Lipos. 35mm props 3 blade brass type. I can't run it flat out as it tries to leap out of the water its that much power. The ESC can be water cooled but as they don't get hot without water I don't cool them. The batteries last about 40 mins.
The motors are £20 a pop and the ESC are around £16 each. I'm never going to use a brushed motor in a model boat again.

HI Thom

The question over shaft alignment, it does cause a lot of extra drag if not in line, but as you say your stuck with it.

Replace the bent shaft, but test the motor out of the hull against the good one, possible it needs "running in" before you splash the cash.

What I meant with the lock nuts and thrust washers, there needs to be slight end float on the shaft, the washers act as a bearing against the end of the shaft tube.

Did you use oil to lubricate the shafts or did you use grease? Grease can cause a lot of drag with high speed motors

Mark

HI Mark,

Think I found one motor which is a bit faulty (doesn't turn as freely as the other) and possibly a very slight bend in the shaft. I'm also using raboesch couplers from motor to shaft so they seem to be fine regardless of the angle. They aren't perfectly aligned but as close as I can get considering the hull design and motor size.

I'll try a new shaft and a new motor and see how it handles.

As for locknuts - everything is tight so there is no movement at all. No thrust washers in place on either side. Would that make a huge difference?

Thanks again for your help!
Thom

HI Thom

I was thinking you had something like 60mm props, with small props there is something wrong with the driveline.

Are the motors and shafts in line both vertically and horizontally?

If you remove the couplings the shafts should be very free to spin if not remove the shaft from the tube and role it across a piece of glass, (the glass is very smooth) there should be no wobble or twitching anywhere along the shaft, if there is the shaft is bent and will need replacing.

The amp test will show which one is the worst and go from there.

Just had a brainwave!!!! (don't happen very often these days.) The locknuts on the props and couplings, is there a little end float, IE. the shaft can move back and forth slightly, possible the shaft is locking up.

Also are the thrust washers in place on both ends????

Mark

Thank you for the tips, Mark! I will check the amps tonight. The props are only 40mm - I didn't think these were too big for the motors, but I am very new to this. Would there be any benefit to trying to get more play in the prop shafts first or should I just look to replace the motors?

I love the speed of these motors, just not the heating issue.

HI Thom

The motors you have selected I think are racing motors for cars, and tuned ones at that. the props your Arun will be using are quite big, so the motors are heavily loaded.
1. Check what amps are going though the motors, in guessing it will be 30 - 40 amps
2. Consider changing motors, possibly use car heater blower motors, cheap and don't use much juice

Using heat sinks and or water cooling, fans etc is only putting a plaster on the problem, it won't fix it..

Regards

Mark