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[rathikrishna]

Friends..at morn, i was deeply thinking about a new propultion systems, for my oncoming submarine projects..and was thinking and refering about many motor systems for a good under water propultion..suddenly, i cam eon one thing..a brushless motor is not commutated by any means of mechanical link..so, it must induce the EMF, between the magnets and sator..through water..so, i tried to run many motors under water..and amazingly it workes perfectly..so, i made a test bed, with motor under water, holding a prop on it..the only thing that i done is insulating the three wires, from motor to ESC with epoxy..it works like a dream..so i took the craft to canal, and lake, worked well..and the motor is in coolest position as it submerged in water..so, i replaced some ball bearings from motor to brass bushes, to avoid rusting..it made even more versatile..now, i am coated the winding in PU paint, for further water proofing..here some test results..
this motor is from a VCR, and i reworked it for my new big tug boat..it is far powerful..here we are taking a test with it..
you can see the reworked winding..
now dipping in water and powering the ESC..as no pulses back to ESC it trips..still nothing wrong is happened..

[rathikrishna]

now the out runner back..can see the insulation on wire junctions with Epoxy glue..

[rathikrishna]

now..time to check out..

[rathikrishna]

will it work..? have any video..? sure see here my first test video..more videos follows even in salt water...SEE VIDEO..

http://www.youtube.com/watch?v=3S0xpp7DvPE

[Circlip]

Like they said in Jaws "We're gonna need a bigger boat", you're gonna need a BIG propeller for that one Krishna, about 6" (150MM) diameter. Otherwise the body is going to mask the waterflow.

  Regards   Ian.

[rathikrishna]

yes..you are true..but not..the motor in first test video, is meant for a big tug, still waiting to fix inside..it used here only for test purpose..now, working on two crafts, one is using a 1200 RPM/Volt outrunner from a reputed company, and one, using a reworked CD motor..on both crafts motor will be fixed directly under the curved area of transom, driving a 1.5 inch pro, and 1 inch prop..will add all and still testing more about this..and also making a submarine, with same idea..

[boatmadman]

I found out by accident that brushless runs ok submerged. I flipped my airboat and proceeded to drive it back to shore with a 6" aero prop on it! Turned it back over, back on the water and away it went - still ok a year on, with no modifications.

[rathikrishna]

Great..great...inspiring..

[rathikrishna]

no more 6 inch props,,but works scaled props..here with a cd drive motor..all reworked and fixed a scale prop, is tiny from a ship kit..

[rathikrishna]

and with a commercially available motor..it will works..because all we know why..and will it drive a craft..? please wait a little..i am making a destroyer with this idea, and later an ARCHERFISH sub..

[rathikrishna]

more test results..

http://www.youtube.com/watch?v=NZ6kKt3ZH7A

 

[sunworksco]

The magnets will rust heavily if they are not sealed.

[gwa84]

hi krishna could you post up a buld ans cerket diogram for just a bec cerket please whant to use some larger baterys to pawer my recever on my petrol boats using big servo and would like to buld them myself

thanks 

[rathikrishna]

GW..its very easy to make a BEC circuit our own..and yes ESCs also..i already posted an article in our forum..here is the link..still i have to add many more stuffs there but still the BEC is complete..here the link..http://www.modelboatmayhem.co.uk/forum/index.php?topic=34614.0   

please use 7806, instead of 7805, and two TIP 3055, instead of one, because a 6 volt regulator will gives us a good voltage stability in heavy duty applications..and yes two power transistors because in a extra heavy application, there must be a chance of over heating so, some loss..by using two, you can avoid such loses..and please add a 2 Ohms resistor, to the Base lead of transistor, and must connect each to each transistor, means, you must use two, 2 Ohms resistor, to the each Base lead of each transistor..this works well..and was using these circuits even on my big competition sail boats one uses ultra heavy duty servos.. )total cost of this circuit costs here as mere 80 Rs/-but works for a life time..can feed it from 6 volts to 14 volts..and if you have a chance to buy a low drop, 78XX series, it will be more satisfying..