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[Vagabond]

Hi, Short time reader, first time poster.
I'm fairly new to radio controlled boats and have fairly recently purchased a wooden thames slipper launch just over a metre long.
I installed a 540 electric motor and a 9.6V battery pack and found (to me) that it went at a nice pace, however it does get very hot under the bonnet for a run of any length of time. I'm loathe to build in cooling vents or even a water cooling system for fear that it would spoil the elegant lines and look of the boat. I was therefore thinking of a brushless conversion because I understand that they run a lot cooler.
What I was hoping from anyone reading this, is advice on what speed brushless to go for for a comparable performance to that of my previous set up, or perhaps if anyone has other ideas for cooling.

Thanking you in advance,

Vagabond.

[Martin (Admin)]

Hi Vagabond,

First thing I would recommend is a smaller propeller.
 That should lessen the amount of work the motor needs to do and cool it down a bit!

 Martin

[Vagabond]

Thanks Martin,
Sorry, didn't think to mention the prop size. It's a 35mm 3 bladed brass prop, I haven't tried reducing the size but I did tweak the pitch of the blades and that helped a little, but still too hot.
Would you recommend a 30mm prop then?

[Greggy1964]

Another suggestion would be to get hold of some copper brake pipe used on cars.

If there is room, wind a length spiral ways around the body of the motor.

Bore a hole in the keel just aft of the propeller blades.                                                    



The uptake can be made from the brake pipe by putting a tight bend in it and cutting off at the bend as shown, the opening will be a long oval shape.

Roughen the sides of the pipe with a sharp file and epoxy to the hull in the hole you have drilled for it as shown so that the oval opening faces the propeller.

A simple outlet can be made from the same brake pipe and epoxied through a support block epoxied to the inside of the hull.

When the motor is running, water will be force fed into the uptake, passing through a connecting tube to the coil around the motor and then out through another pipe to the outlet.

This constant steam of cold water will take the heat away from your motor and keep it cool

This is a cheap way of doing it without buying fancy bits and does just as good a job

[FullLeatherJacket]

Most stock 540-size motors are not rated to run at more than 7.2v. The problem is knowing what sort of 540 you have, although this one sounds quite typical. The basic rule is that if a motor gets too hot to touch then it's being overloaded with either too big a prop or too many volts or both.

I would first suggest installing a different motor. A 555 would fit the mounting and the coupling which you already have, and would have more torque at the voltage you are using. It's also rated for 12v so it wouldn't get hot and, best of all, would draw less current and so last longer between charges.

FLJ

[Vagabond]

I did think about that method of water cooling, but didn't fancy the idea of it spoiling the nice clean lines of my hull.

The motor I currently have in it is an "Mtroniks Purple Heat 540" that I bought from Cornwall Model Boats. It is rated for 9,6V.

So the main plans are to trial a smaller prop or a bigger engine. I was also curious about the brushless option however as I'll be at the Shepton show this weekend and thought that it might be an idea to get the gear at one of the stands. Is it worth the switch or do people recommend sticking with the brushed?

[tolnedra]

Hi there Vagabond!

See you at the show this coming weekend! Try visiting FLJ (Action Electronics) and/or Mark's Model Bits for help and advice. Both are very helpful and knowledgeable. (and are always ready to help reduce the weight in your wallet at the same time!) Only joking fella's, see you all at the show.

Danny (just a very satisfied customer)

[PMK]

Blimey, if I were in Vagabond's shoes I'd be tempted to heed all that advice already and clean-clean forget any ideas about brushless power plants for the moment. If I had a boat of which I'd be reluctant to mess up the curves, I'd at least try using the proper voltage first.
Let us know if you find a brushless that still runs cool when it's got waaay too many Vs stuffed up it.

[Dueller]

I too would recomend a chat with FLJ at Action electronics.

I had a problem with the speed controller i was using, FLJ answered the question and although the solution was one of his products, the advice was totally free and there was no obligation to buy. The product however was exactly what i wanted.

The other advice you have been given is also quite relevant, motors usually get hot when overloaded either by voltage or work (prop size)
I once ran a 12 volt motor at 18 volts and solved the problem in exactly the same way as Greggy 1964 describes. Also the squirt of water from the outlet was very realistic.

[FullLeatherJacket]

Purple Heat 540 is exactly the WRONG type of motor for this model!
I can guarantee that Dave @ ACTion will sort you out at Shepton Mallet if you introduce yourself as the guy with the drag-racing slipper boat.
FLJ

[Vagabond]

Alright, thanks all!
I'll be down Shepton Mallet on Saturday, so I'll stop by and have a chat to the ACTion guys.

Thanks!

[Guy Bagley]

any images of the dragster slipper launch !-  would love ot see it !