Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Navy - Military - Battleships: => Topic started by: funtimefrankie on August 31, 2006, 02:04:41 pm
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I've just fitted water cooling for my Huntsman to cool the graupner 700 motor. On the first outing this morning nothing seems to happen, just a few blobs of water in te tube.
What have I done wrong? the tube is clear, you can blow through it. Should the tubes be primed before running, or is the scoop in the wrong place?
Any help appreciated
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If you had put a 90 degree angle at the bottom so the water is forced up the tube when going forward would have been better, To me it is flowing across the end of the tube, with very little going up, ron h
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Does look as though it could be turned slightly to face the prop square on. Just put glasses on. Tube definately needs a right angle bend so water is pushed into it.
Richard
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this is a set up was used some years ago with a pair of 700bbs ,the boat has not been in the water for a long time as you can see, it took some time to get the tube a piece of 3/16 copper tube bent, and rudders in the best place. I Had to move it a lot closer than I though I would need but this gave a jet abt 20" long from a 1/8 Tube outlet Peter
sorry the pick are not very good but was unable to get the boat off the shelf
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I fitted a Graupner one of these to my first boat.
Since then i have been fitting a much simpler one in the base of the hull, two holes one at the front and one at the back about 10mm long, 4 wide and 2 deep. Works on a vacume the second hole pulls water through the first. Needs to me mounted in line with where the prop tube comes through the hull.
I run one on each side, one for the motor and one for the speed controller. Very little set up, two small holes and off you go.
I think they are about 4 quid from hobbystores.
I will upload a picture later
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Hi FTF,
I had the same problem last season. I had changed all the parts Motor c/w brush box tubes-cooling coil and water pick up tube to a new fast electric hull. But no water came out. This was strange, as the new boat was only an up date of the old one which picked up water with no problems. The answer turned out to be the new silicon tube which I fitted to the new hull. Because the tube is so flexible, it expands easily over pipe ends, but had a smaller inside diameter, which held back the flow of water. I now only use silicon tube to join lengths aluminium tube which has a larger inside diameter, offering less internal resistance. There is a new (plastic) tubing available from Hanna Parts called Tygon tube, which has a fractionally larger internal bore. Although I have some I have not yet tried it out, so don't know if it will improve the situation. I have tried to get hold of larger bore silicone tube at shows etc. But they all seem to stock the smaller bore now.
With regard to your pick up. You could try filing a slot in the front edge of the tube, and plugging the bottom.
Several of my slower electric models use this style of pick up.
Regards Bob
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I'e added a scoop at right-angles. In the garden pond, holding the boat it produces a good flow. Yet to try it in the boating lake.
Now i'm wondering if it's too big and will produce a bit of drag.
The other thing is, I forgot to mention before, is the battery gets hot. Is this OK its 9.6 NiMh 3600. or can this be added into the water cooling circuit? I thought of sitting it on a brass sheet with tubes soldered to it.
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