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[Bill D203]

Dose anyone know where i can buy a water coooling coil for a 900 motor. IF so can you pm me the link. Or if you have one and want to sell it pm me.
Cheers

[daveorgan]

try cornwall model boats they do one for the 820bb the sizes are on there i think you will find this will fit

 http://www.cornwallmodelboats.co.uk/acatalog/water_cooling.html 

[Bill D203]

try cornwall model boats they do one for the 820bb the sizes are on there i think you will find this will fit

 http://www.cornwallmodelboats.co.uk/acatalog/water_cooling.html 

Thanks for that, it will do nicely

[pompebled]

Hi Bill,

If your motor is a 900 type, the outside Ø will be 51,5 mm (a tad over 2") the coils for the 850BB are Ø48 mm, so that won't fit...

You can try to bend the coils open, but that would make the cooling performance worse if the coils don't fit snuggly.

If it were a 600 size motor I'd advice you to get a one meter piece of Ø 4 mm thin walled aluminium tube from your local hobbyshop, but that would only give you a few windings around the can before you run out of material.

Depending on how hard the motor has to work, how hot it'll get, you may get away with only brushtab cooling; a brass tube, soldered onto the (pre bend) brushtabs.

Fed into the cooling loop, this draws the heat away from where it originates, at the commutor.

The picture shows brushtab and can cooling on a 700 motor:


If the motor gets too hot for just brushtab cooling, it's possible your set-up is flawed, or the hull in question is a large fast moving boat, with a relative high ampdraw.

In that case a coil will only help marginally, a full jacket, like in the picture will work much more efficient.

I have a tutorial (and pics) on my computer, if you want it, PM me an email address and I'll mail it to you.
If all fails, I could even make you a cooling jacket to fit your 900 motor.

Regards, Jan.

[Bill D203]

Hi Bill,

If your motor is a 900 type, the outside Ø will be 51,5 mm (a tad over 2") the coils for the 850BB are Ø48 mm, so that won't fit...

You can try to bend the coils open, but that would make the cooling performance worse if the coils don't fit snuggly.

If it were a 600 size motor I'd advice you to get a one meter piece of Ø 4 mm thin walled aluminium tube from your local hobbyshop, but that would only give you a few windings around the can before you run out of material.

Depending on how hard the motor has to work, how hot it'll get, you may get away with only brushtab cooling; a brass tube, soldered onto the (pre bend) brushtabs.

Fed into the cooling loop, this draws the heat away from where it originates, at the commutor.

The picture shows brushtab and can cooling on a 700 motor:


If the motor gets too hot for just brushtab cooling, it's possible your set-up is flawed, or the hull in question is a large fast moving boat, with a relative high ampdraw.

In that case a coil will only help marginally, a full jacket, like in the picture will work much more efficient.

I have a tutorial (and pics) on my computer, if you want it, PM me an email address and I'll mail it to you.
If all fails, I could even make you a cooling jacket to fit your 900 motor.

Regards, Jan.

To Be fair it is not getting Very hot but hotter then you can hold your finger on. I had it on the water for over 45 mins this afternoon, so it had been working. Thanks for the info Jan I will knock up a jacket in my shed soon. I have to say yours looks good. Before I went into building one i wanted to find out if somone sold one made.  But thanks anyway for your help it has been most helpfull.
The boat is a MBD 38" fishing boat Cygnus with a 3 blade 45mm brass prop. It is not pulling to much curent as i have a Action diode unit rated at 16amp which is not warming up at all. Im happy with the speed and time on the water just need a tad of cooling.

[Welsh Wizard]

Bill why not do what I usually do with mine,get a tube a couple of mm less than the motor amd coil copper brake pipe around it.Obviously you will nee to make the coil smaller than the motor can so it will cool it.
Thats all that cools the pair of 900 in my cygnus and perkassa etc

Dave

[Bill D203]

Bill why not do what I usually do with mine,get a tube a couple of mm less than the motor amd coil copper brake pipe around it.Obviously you will nee to make the coil smaller than the motor can so it will cool it.
Thats all that cools the pair of 900 in my cygnus and perkassa etc

Dave

Hi Dave
Yes i may well do just that.