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Post by honda73 on Sept 25, 2009 11:48:13 GMT 1
Well, being of the old school and an instrument maker to boot, I have a lot of the Bismark editions stored from about issue 15.... I am however going to build this ship just as it should be with three motors and 3 props, I have even made scale brass rudders, the guns will be next to make and then down to finishing off the planking of the hull!! (when the motors are in) Smoke, turret rotation, lights, water cooling, so much to do and so little time But the date when it will be finished...ummmmmmm
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Post by Mark on Sept 25, 2009 12:14:27 GMT 1
Sounds like it's going to be a cracking model when it's finished What are you doing with the cooling water ? I wouldn't have thought it was visible on the real ship, being under the water line.
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Post by Deleted on Sept 25, 2009 13:10:54 GMT 1
Water cooling, thats an idea.
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Post by honda73 on Sept 28, 2009 18:29:07 GMT 1
Hi Guys, I have tried several versions of motor cooling by either fine tubing coiled around the 3 motors, they are all the 400 version motors, with a pump so I can suck it in at one end and blow it out the other so to speak underwater is no problem, or then again I can go the electronic version with Peltier heat pumps and a turned aluminuim jacket for each motor with the heat pump mounted on a flat deck machined into each jacket to keep the 'engines' cool, the coiled pipework is easier to do..ish (limited space) the peltier heat pump maybe a problem with available battery space and power......but we will see....... Ha Ha Cap'tn
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Post by coenie on Sept 28, 2009 20:41:05 GMT 1
Gee oaks, this we must see!! Honda, how about some photos of those you tried already?
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Post by honda73 on Sept 28, 2009 20:50:26 GMT 1
Ok, as yet I have not shot any photo's of my experiments with cooling of the motors but I will see what I can put together, if not I will do some layouts in Autocad to explain the system and possible cooling control as soon as time, work, and family permits.
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Post by Mark on Sept 28, 2009 23:26:19 GMT 1
You may find that water cooling is unnecessary. The larger motors shouldnt' get that hot, particularly at scale speeds. However, the coils and pump would get my vote - Keepo it simple
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Post by markus on Sept 29, 2009 9:42:22 GMT 1
speed400 motors don't need any watercooling - after one hour on the pond the motors are just 40-50 degrees centigrade, nothing to worry about but if you wanna cool them: using the hulls' sea water chests for cooling the speed400 might be a smart idea.... you might place the inlet/outlet tube in different directions so there's no pump needed markus
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Post by popeye on Sept 29, 2009 11:48:40 GMT 1
You should'nt need a pump. A number of model shops sell inlet and exhaust hull fittings for just this purpose. The inlet is a scoop that will force water in when the boat is moving. They also do ready-made cooling coils for the Graupner Speed 400. See Cornwall model boats as an example (do a search on "water cooling" and you will see items and pictures) www.cornwallmodelboats.co.uk/index.htmlWater Scoop Set Plastic Smart black lightweight scoop and outlet with brass nuts. Part No: P5511772 Price: £1.05 (Including VAT at 15%) Euros: €1.15 (Inc VAT) / US Dollars: US$1.46 (Tax Free) Watercooling Coil 380/400 Motors This coil can be fitted to electric motors to provide water cooling. Case diameter 27 - 29 mm Suitable instalation 360, 380, 400 & 480 Motors Part No: G3325.1 Price: £8.50 (Including VAT at 15%) Euros: €9.31 (Inc VAT) / US Dollars: US$11.82 (Tax Free)
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Post by popeye on Sept 29, 2009 11:51:31 GMT 1
PS - Cornwall also do a water-cooled plate to mount the Graupner speed controller on.
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Post by markus on Sept 29, 2009 16:47:04 GMT 1
PS - Cornwall also do a water-cooled plate to mount the Graupner speed controller on. do they also have a water-cooled plate for the steering servo? ;D ;D ;D seriously, all those cooling stuff is intended for use in a racing boat whose motor discharges the cells in less than 5minutes due to extreme high current drain (30-80 amps) so 'cooling' an 30 amps esc with a max. current drain between 3 and 9 amps (depending on the number of motors connected to the esc) is absolutely useless. my 20 amps esc's did not even get warm in use... markus
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Post by popeye on Sept 30, 2009 10:27:57 GMT 1
Ah, but, you haven't seen my Bismarck doing 100 knots down the length of an olympic swimming pool !!!
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Post by popeye on Sept 30, 2009 10:55:27 GMT 1
PS Markus, you are quite right. Because I am fitting miniature circuit breakers in the motor supply leads (they will be fitted in the aft deck with the reset button sticking up at deck level so I can see - with binoculars if necessary - whether one has tripped) I needed to know what the stall current of the 400 motors is. At 6v the current is about 10A. The running current is up to about 7A (full speed). As I use two of the 30A+ controllers, supplied by Hachette (I bought another one so that I can control each motor separately) the controllers barely get warm, even at stalled current.
I ran the motors at stalled current (e.g. weed wrapped round the propellor) for about 1 minute, as the overcurrent trips take about half a minute to activate, and they also barely got warm. This was with 6v, presumably if you (over)run them at higher voltage then you might need motor cooling.
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Post by markus on Sept 30, 2009 15:08:17 GMT 1
PS The running current is up to about 7A (full speed) 7 amps at full speed ?? did you use speed400 6volts type instead of the 7,2volts ones?? my speed400 only drawed 3 amps at full speed...maybe you measured the current drain of both motors together? markus
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Post by honda73 on Sept 30, 2009 21:05:44 GMT 1
Hey guys, I like the amount of replies and comments that my original mail made, I profess not to be any kind of expert in this field of scale ship building, I just like to make things correct, the Bismarck was a wonderful ship built for all the wrong reasons in reality, but this one will be as true to the original as I can make it, it may not need a 3 prop drive or motor cooling, it does not need smoke or lights or even to be able to rotate the guns, but at the end of the day we all build these scale models to be as good as each of us may be able to produce, in my case I do not want a 2 prop ship or wood prop shaft 'A' frame supports, it will be, and has been scaled up from the original drawings to be made in my spare time, but like me if the thought takes you down the road of motor cooling, lights etc then that's what you do.
For me, Markus pointed the way for 3 props 'thank you'! the rest is purley a, 'can I do it', 'shall I do it', or will I do it, not just for the Bismarck but for anybody who may need to do it.
It's getting cold enough to freeze the shells of a brass monkey Cap'tn.
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