Water Cooling Intake Pipework.

[Rick DevonshireParticipant @rickdevonshire]

Having tried it in the past with less than satisfactory results I am about to install the water cooling intake pipes on my latest model ( a twin screw crash tender)and seek some advice on the following:-

1/ What diameter of pipe is it best to use for the intake?

 2/ How far back from the prop disk is it best to locate the intake end of the pipe?

3/ At what height with respect to the disk of the prop and on the rising or falling curve of the blade?

4/ What diameter of silicon tubing is it best to use to connect to the cooling coil round the motor?

(I would appreciate informatiom from those who have actually successfully installed this feature please).

Rick. 

[Rick DevonshireParticipant @rickdevonshire]

The geometry of the system.

[Paul TParticipant @pault84577]

Hi Rick

 

In answer to your main question.

 

The last time I installed a water cooling system I used 15mm copper pipe, the intake positioned 0.545mm from the top curve of the 80mm 4 bladed prop, the scoop was made from a 15mm end feed copper elbow (plumbing fitting) cut at a 110deg chord across the x axis.

The silicon tubing was difficult to find at 15mm i/d so I used 12mm soft copper tube and coiled this around the motor can.

 

Big in’it

 

Regarding your last point are you hinting that some members talk bo**ocks.

 

Paul

 

[Rick DevonshireParticipant @rickdevonshire]

Thanks Paul,

Your method is interesting, I expect you were scooping up quite a large quantity of water. I had never considered such a size of tubing.

Your is the only reply, does this mean very few have infact managed to get this method to work succsefully or has my last line miffed many of the usual contributers? eek! !!

Rick.

 

[Paul TParticipant @pault84577]

Hi Rick

 

Have a look at Cornwall Model Boats

http://www.cornwallmodelboats.co.uk/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww%2ecornwallmodelboats%2eco%2euk%2f&WD=cooling%20water&PN=water_cooling%2ehtml%23aG2356_2e1#aG2356_2e1

Its full of goodies that might help you decide.

 

Perhaps you did upset some folk after all.

 

Paul

[Len OchiltreeParticipant @lenochiltree67043]

Not me, I have never cooked a motor so have not needed a cooler.

 

   Cool  Len

[michael kemishParticipant @michaelkemish72883]

Hi, have you thought of using a water pump for the set-up?

I read somewhere that a windscreen washer pump can work, and also that a fuel pump off (I think) a model aeroplane can work.

I admit I hav’nt tried either, yet,

My Matilda may need cooling, I’ll wait and see after sea trials.

I’d like to know how you go.

Mick

 

 

[Rick DevonshireParticipant @rickdevonshire]

Hi Michael,

Actually I am not too sure what to do. Westbourne Models, who supplied me with the motors, (Graupner Speed 600-Ecos) say I probably don’t need water cooling as they are very efficient power units so I think initially I might just ensure plenty of ventilation in the motor area and see how things go.

I have the cooling coils to fit if necessary but would like some guidance on the location and shape of the pick-up scoops just in case. Corwall Model Boats sell a number of pickup alternatives and sizes of plastic tubing to link them up. It is  worth having a look at their web site mentioned above.

On the subject of fitting pumps I am trying to ensure the weight of the craft is kept in check to ensure a lively performance.

Rick.

 

 

 

 

Edited By Rick Devonshire on 09/02/2010 11:19:31

[michael kemishParticipant @michaelkemish72883]

Hi Rick,

I would tend to go with the experts who have been down this road before.

Like my work collegue said today, “Don’t have a heart attack over things that might not happen!”

If the motors get hot, retro-fit cooling, (just another chaleng in scratch build!)

 If not, don’t.

That’s my theory.

Mick

 

[Bob Abell 2Participant @bobabell2]

Hi Rick

 

Not one of my 15 powered models have water cooling……. Never had a problem with any of them

 

But my latest will probably be fitted with water coils…………..big motors running on 24 v……Don`t fancy it though

 

Bob

[Dave MilbournParticipant @davemilbourn48782]

Washer-pump motors are seldom rated for continuous running, chaps. You’d really need something like a peristaltic job, and they are EXPENSIVE. For instance, have a look here:

 http://www.micropumps.co.uk/index.html

 

Glad to see you’re having second thoughts about those aluminium paddles, Bob. I was beginning to have nightmares about ’em!

 

Rick – 3/16″ bore flexible tubing should do the job of connecting the cooling coils to the inlet and outlet. You can obtain this size in a nice flexible rubber form from pond and aquarium suppliers. Keep the pipe from the cooling coil to the outlet as short as possible (best exit through the side of the hull, not the transom).

 

DM

[Rick DevonshireParticipant @rickdevonshire]

Many thanks chaps for all your nuggets of information. Do keep them coming, they are very useful.

Rick.

 

 

[NederlanderParticipant @nederlander]

Over here in the states we have some bath accessory that sprays a cleaner solution around the inside of the shower stall every day. If you find a throw away of one of these whatchamacallits they have nice little diaphragm pumps that operate on 6vdc.

[Rick DevonshireParticipant @rickdevonshire]

Thanks for the info. I have not seen such a piece of equipment this side of the Atlantic.

Can you give me more details please?

Rick.

 

 

[seabird1Participant @seabird1]

Hi Rick… If your’e using Graupner 600 eco’s (do these have integral fan fitted, some of the 700’s do) if they do then you may get away without having to water cool them. The main thing to remember about water cooling on a model boat is that its not an exact science! I know this doesnt help much but most of us have to use the old fashioned method of ‘trial & error’ to get our water cooling to work usually.

 

If you look at Cornwall Model Boat website under their cooling section, Graupner have some very smart all in one inlet/outlet water scoops which only need positioning either side of the keel, ie; not near the props for effectivness. They are low drag, and as the outlet is positioned behind the inlet port, suction plays a good part in ensuring the flow works well, but its just another option to consider.

 

Regards

 

Seabird1

[aquaplanerParticipant @aquaplaner]

Respected Modeller..its easy to instal a cooling system, to your motor, or motors..in two way..first one is, complicated, as you can make a simple centrifugal pump, with foam board, and can fix it under the hull..so, can drive with a motor, with a vertical shaft.so it will pump in water at stand still..but eats battery a lots..and will be a waste, as it pumps water every time..second one is far easier, and economical..fix a intake scoop, just after the prop, and make its mouth slender, by cutting it in a slanting manner..and you can make this scoop, with pvc pipe, or can by coper tube that used to wrap the deep freezer tray, in to 4,5,6 8 mm dias, easy to bend, never rust, and can also use to wind on motor..see this..

[aquaplanerParticipant @aquaplaner]

sorry for the repeated postings..connection speed is too low…shows the scoop…you can adjust the mouth of the scoop with rotating it, up to high flow..and can fix it later with two part epoxy putty…and see its working here…

see a cool video here as it shows the working of the pump..as motor speed increases the pumping also increases…i drove this craft for more than an hour..actually the motor was reworked to 9 volts..but she was running with a 12 volt battery…cool….its so easy and effective to fix a motor cooler…

 

http://www.youtube.com/watch?v=522QLfwom9I

[aquaplanerParticipant @aquaplaner]

after fixing the tube on motor, please apply some “heat sink compound” can purchase from any electronics shop, as it used to seal the heat sinks for integrated circuits..its cheap..but seals any heat leak..and provides an excellent heat transfer..we can also make scoops with emptied ball point pen body..works well..

one of the another easy method is, collect a big heat sink from a computer mother board, and fix the motor on it, with pipe clamps. apply heat sink compounds..make a cutting on hull, just to the place that motor fixes..connect the motor to the shaft, with UV joint, or directly, and place the fins of heat sink facing in water..after seal all gaps with high resistant epoxy putty..so, at present, the fins of the heat sink will be in water as we place the craft in water…motor will be over the heat sink..soo coolll…i use this method for big motors, like CR 1200…for sprinters..and its easy to cool a brush less with a heat sink, scraped from an SMPS, of a computer..works well..

[aquaplanerParticipant @aquaplaner]

one of the main reason of motor over heating is high current consumption..in my research and examinations, i found one fascinating thig is, after a partcular RPM, we will lost power, in the foam of cavitation, and aqua planing..and in the case of a displacement craft, the drag also increases to the speed..so a scale speed is preferable for such crafts..but we will open throttle, as excitement increses..so, we can limit the current, flowing to the motor, with a simple current limiter circuit..and can adjust its output to our desired level, by manual, or by radio..so, the motor never heats up..and lives longer..and longer…

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