[Score: 8/10] 37"/3600g ILLINI NATIVE Capable of 10mph and a runtime of 45mins Twin Propellors (5 Blade 50mm) Direct Drive to a 775 JOHNSON TYPE (5 Blade) Powered by NiMH (8.4v) 3Amp/h Batteries Controlled Through DIMART FAN-COOLED 320A 6-18V (10Amps) ESC - Comments: DUMAS AMERICAN BEAUTY TOWBOAT KIT; GIVEN THE ILLINIWEK MARINE PAINT SCHEME, THE DECK IS COVERED BY 3/16" BASSWOOD SCRIBED SHEATHING PROTECTED BY MINWAX POLYURETHANE. SHE FEATURES FLANKING RUDDERS WITH RIVABO 5-BLADE BRASS WHEELS, TWIN 1.5V WORKING RADAR ARRAYS, TWIN 6V WORKING DECK CAPSTANS, 9V LED NAV LIGHTS WITH AMBER DECK STANDING LIGHTS AND DUAL BRUSHLESS VENT/COOLING FANS ON THE INBOARD SIDE OF THE FUNNELS (FOR THE FUN OF IT). SHE IS THE SECOND ADDITION TO THE ILLINIWEK MARINE RC FLEET SHE'S PUSHING AHEAD A SET OF DUMAS 1:48 RAKE BOW & BOX BARGES ACROSS THE WINDING CARPET RIVER
before you fit a water cooling system try a smaller prop. You need to think of the gearbox in a car. Too big a prop can be looked at as being like trying to drive off in top gear! A smaller prop will allow any given motor to spin faster and strange as it may seem use LESS not more current. If you keep the drawn current down to the limits set by the motor constructor then its probable you will need no extra cooling. If the boat moves faster than you want use the throttle its what its for. Throttling down also extends battery life. The air intakes on boats like this were intended for IC engines and they NEED air to work.
Ran the model again Sunday for the last time this year, proved well with a little ballast added. After 15 minutes of running checked the temps on the motor, Only just detect the suggestion of warming up, being such a cold day. The water cooling scoop has not been added as yet. Maybe not even needed at all. Hope to continue to source / make the fittings oven the coming months with the boat show Saturday perhaps for a new LiPo battery.
Hi Richard, with a bigger motor and smaller prop you may not need the water cooling, none of my boats have cooling, what i would say is that switching to a gel battery will be heavy, stick with your 7.2v batteries and give it a try, it might last a bit longer but with your twin battery set up you will get about the same run time. Mark
for the purpose of testing, don't go out and buy expensive props, just buy cheap plastic two blade ones, I always use "x" blade, they are a coarser pitch, "s" blade are less pitch. Get a few to test, 35mm, 40mm, 50mm. Fit, short run, see how hot things are. Whilst you don't want to go fast, don't forget this is a big heavy old girl, its better to be overpowered than under powered. If it was me, I would get a graupner 700, watercool with a cooling coil, probably settle with 45 to 50mm two blade "x" prop, run on 12v, this will give some speed and durability. Don't assume that just because the model shop suggested it, its the holy grail, many many times we have seen evidence of very poor advice given by so called experts😡 https://www.ebay.co.uk/itm/Graupner-Speed-700-Turbo-Electric...
the scoop should be fitted behind the prop so prop wash is driving water through it whenever the motor is running and the cooling coil fits around the motor join the two up with fuel tube etc. then the other end of the coil connect to an outlet ( unless you want a self filling boat) http://www.cornwallmodelboats.co.uk/acatalog/ style='background-color:yellow;'>cooling-coils.html http://www.cornwallmodelboats.co.uk/cgi-bin/sh000029.pl?REFP... style='background-color:yellow;'>cooling%2dcoils%2ehtml&WD=scoop%20water&PN=water_cooling%2ehtml%23aG1427#aG1427 As to sitting on your boat you could put it in the water and get some one to hold it while you run the motor up and watch the current used. closing off the cooling vents to an electric motor not used in a speed model shouldn't be any problem if you have the correct prop an electric motor should only get hand warm. The temps you indicate would have burned out your motor even if there had been no covering over the motor at all. With an electric ( brushed) motor the more you load it the higher the current flow and the hotter it gets. Stall current tend towards infinity you have what I think is a 60mm prop and that's a BIG prop being 3 bladed makes the situation worse since there is increased blade area against a 2 bladed prop. If you intend to use that prop then get a motor man enough to swing it.
Hi reilly4 I do not think it is as large as 60mm as it is a three bladed prop, if it was a two bladed one I would agree with you as the blades would be directly opposite each other hence 60mm, but being 3 bladed they are not 90 degrees to the centre point, without taking it off and drawing a circle around it to measure I would hazard a guess it is a 30mm prop. If memory serves me correctly the late Swindon Model Shop which was run by Yan who knew his stuff recommended the 540 motor along with the prop for the size of the boat. I will check the Sea Commander plans as I think it has the size of the required prop listed. Haverlock the motor is rated 4.5 to 15 volts and the battery is 7.2 volt, I would have to run the boat in water to see what the motor is drawing under load, I may get a tad wet trying to keep up with it to read an amp meter, or sink the boat by sitting on it😉 I think the overheat problem was to do with the motor mounting braket covering the front air slots on the motor. However I have a water scoop which I did not fit at the time of building so may retro fit and buy a new motor set up for water cooling, the next question would be where abouts do I fit it?
At the risk of being repetitive get yourself a watt meter that way you can see how much current your motor is drawing. If a motor overheats you are either running to high a voltage or to big a prop. If you are intending to push the envelope you can buy a cooling coil to fit over your brushed ( or inrunner brushless) motor and use a water scoop thus water cooling your setup.
Hi Richard, as an extra to Dave M. the battery packs are different sizes, 5000mah and 3300mah, if both batteries are connected together they will cause problems with power balance, as said the cooling slots are covered. You said the motor was cooking, have you tried it since? maybe it was the ESC that cut out through the overloading with the prop to big. PS what size prop is fitted? The 540 in the 4th pic may not be big enough, a 600 size or even an 850 would give a lot more torque and probably more speed, you can back off the throttle but a small motor will always struggle, and will probably be run at near full power a lot of the time. Hope this helps Mark
Hi Steve Its fresh water but the much larger Marine Lake a quarter of a mile up the road is salt water. I don't know if you are allowed to sail models there. I used it once in the 1990s with a fast electric but had to flush out the cooling system after. Went in the early morning when it was quiet so I didn't get spotted. Boaty😊
Hi Chris I know of no easy way for you to determine the voltage. However motors do have a coil resistance value measured across the terminals. Also if you can see the coil windings a thick wire usually indicates a motor designed for high speed and current. A thinner wire may produce a motor with lower speed and less current and more tork. If you check the Graupner and look at the windings this may help you identify the other two. In my experience it's usually too low a voltage that's the problem resulting in slow revs and little if any tork. At the other end of the scale too high a voltage will result in very high revs and lots of sparks from the brushes. In this case if you continue to apply the volts you will damage the motor. Many electric drills were powered by motors rated at 9v and did indeed have an impeller cooling fan. That said Mabuchi and Johnson produced a vast range of motors all looking similar on the outside but wired very differently inside depending on the ultimate use. I suggest you try with progressively higher voltages and assess which is best for the two unknowns. Finally most motors are designed to work over a range of voltages so I usually measure both the upper and lower values so I can select the right motor for a particular model.
I have several motors that all look very nearly the same. One I know is a Graupner Speed 600 which is 8.4v but of the other 2, one is said to be 12v(was working with an 11.1 lipo) and the other one is unknown. It has a built in cooling impeller so probably came from an electric tool of some sort. Neither of these 2 have any markings or labels. Is there any way that I can test them for their normal working voltages without endangering them? Chris
Jaydee by IanD Sub-Lieutenant Posted: 2 months ago
Hi Dave I've attached a photo of the prop as you asked. You can just see where I've shaved it down. This seems to have eased the overheating considerably. You can also see the water inlet for the cooling system that was used with the original diesel engine. This is now piped directly to the outlet on the port side (you can see it working in some of the action photos). The other photo is a fore/aft view of the central bay which contains the motor, ESC and battery. Ian
Hi there NP. Where do you want to start, I have converted several Richardson / Southampton, tugs. The first thing is do you want independant motor control, not found that i made a deal of difference, I now fit 1 ESC for both motors. Sound, when sailing you can't hear it, you can't hear most sound systems more than a few yards out, can be fixed but heavy so be careful, Smoke, in reality, smoke shows that the engines or injectors need servicing, on the model, try a computer cooling fan, the small ones to blow the smoke up the funnels. Better radio system, YES, which one your choice, but by a 6 or more channel system. Battery, a 7.2v buggy type NmHi pack will fit under the stern hatch, (just) or in place of the smaller battery under the front hatch, weight is not a problem, just get the balance right. I have altered the control cabin on 2 of my models, moved forward to the edge of the lower cabin, removing the steps down to the deck, also repositioning the funnels into different locations, ! model further back and the other the funnels were cut down and fitted to the top of the air intake casings, with a firefighting gantry across the top of them. In short, TX / RX upgrade, ESC, single or twin, 3300mah Battery last for hours, anything else, up to you. Hope this gives you some ideas. PS when cutting the wiring keep the motor wires as long as possible, i cheated and fitted the battery leads with a Mini Tamiya / Standard Tamiya converter Regards Mark
Managed, at last, to get to the water on Monday at the Knap in Barry, South Wales with the Vale of Glamorgan Model Boat Club. Unbekannte Flitze was very fast off the mark, agile with incredible turns and generally good control. After about 5 or 6 minutes she became sluggish and I started to bring her in. About a yard out she just pointed her nose in the air and bubbled ignominiouly as she went to the bottom. Only one answer. off with everything but my pants and in we go. Rumour from Ken Thompson was that i was practising for the local Iron Man event. One poor lady actually believed it. The problem was a loose water cooling pipe....my fault for p... poor preparation. Note to self... buy chest waders.