Have a brushless coversion - RC Groups
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Dec 01, 2010, 02:22 AM
matt the cat

Have a brushless coversion

Hi , i have a kyosho i think is the name race boat that has been coverted to brushless. Was wondering what prop i would want to use for it? It has a 540 brushless motor in it with a esc that can handle a 6 cell, but i have been told by the pervious owner that anything over a 3 cell would fry the motor.
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Dec 01, 2010, 08:23 AM
Surface, Air & Water Rc Toys..
freechip's Avatar
Motor? ESC? KV rating? hull size? Not enough info to get a proper reponse or recommendation. Without knowing nothing I will just recommend you use the stock prop...What ever that may be...
Dec 01, 2010, 08:28 AM
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F1 madness's Avatar
Agreed need more info or even pics
Dec 01, 2010, 05:55 PM
matt the cat
Ok guys point taken! It is a deep vee. 26 inch long boat. With a velineon 3500 brushless motor. 10turn 3500kv. The esc is a 160 amp aircraft speed control. That is rated for 6 cell. Also has seprate 700mi-amp nicad j.r. Battery running the servo. Hope this helps?
Last edited by matthew james; Dec 01, 2010 at 06:08 PM.
Dec 01, 2010, 06:15 PM
matt the cat
Here are some pics of boat
Dec 01, 2010, 06:29 PM
I feel the need for speed!
scorpion1's Avatar
I've done a few of the entry level boat conversions myself. First thing is you need to make sure your motor mount is gonna hold. If you have to add additional support, add it. Secondly, the motor is a pretty high of a kv for a boat, so 2s is max you should use. However, the Veilineon is a torquey sucker and should do well. Next, what is the diameter of the submerged prop? Shouldnt be more than 32-35mm max. How are you cooling the ESC?
Dec 01, 2010, 08:13 PM
matt the cat
1.6x 2.5 pro boat composite prop. And esc is just being cooled by the heat sink on it. Now i have not run this boat yet, and bought it from a guy here on r.c. Groups, he said boat does 30mph on a 3 cell 2200 li-poly and that the esc can handle a 6 cell but the motor would not. He told me if i were to try to run anyhing more then a 3 cell i would fry motor. He also told me that boat has so much power that it sometimes wants to jump out of the water, this is why as we speak i am making stainless steel trim tabs for boat. Just dont know what else i could do to make boat more stable and faster? Faster with me is a obsession! OH YA THE PROP HE HAD ON THIS BOAT WAS WAY SMALLER THEN THE ONE ON IT NOW. GUYS AT HOBBYSHOP TOLD ME IT WAS PROBLY JUMPING OUT OF WATER AND CAVATATEING BECAUSE PROP WAS TO SMALL AND SET ME UP WITH THE 1.6X2.5. DONT RIGHTLY KNOW IF THAT ONE WILL PERFROM BETTER OR NOT? sorry caps! ooopps!
Last edited by matthew james; Dec 01, 2010 at 08:18 PM.
Dec 01, 2010, 09:20 PM
I feel the need for speed!
scorpion1's Avatar
The prop was smaller cuz he was running 3s i guess. With that prop you need to try 2s first...................it may be all it can handle anyways. 3s is just too much juice in my opinion.
Dec 02, 2010, 09:04 AM
matt the cat
Is there anyway I can put a watts and amp meter on boat to see what I am pulling in amps and what I am getting watts? and If I can would I just hold the boat and rev thr throttle? Excuse me if I sound like a guy that does not know what he Is talking about. I AM! LOL. My thing is electric planes. have over 30 of those and I am sure boats are a hole different ball game. Thank you for helping me out.ALso, I DO HAVE A VENUM 7.2 1800 NMH pack I could try first?
Last edited by matthew james; Dec 02, 2010 at 09:09 AM.
Dec 03, 2010, 02:56 AM
nick 30
nick30head's Avatar
you can buy a meter that sits between the battery (source) and the esc (load) then you can sit it in the boat while its on the water to get accurate readings, i have one from turnigy but there are also one's called a ''watts up'' meter, should be able to get them from www.offshoreelectrics.com or www.hobbyking.com
Dec 03, 2010, 09:09 AM
matt the cat
ya i have the e-flight one but i did not know if it makes a differance weather the boat is moving or not?
Dec 04, 2010, 05:52 AM
Boaters are nice people.
Originally Posted by matthew james
Just dont know what else i could do to make boat more stable and faster? Faster with me is a obsession!
Hi Matthew,

I've been working on this hull a few years ago for a friend and 30 mph is about as fast as it will go without becoming uncontrolable.
If you want to go faster, you'll need another hull, preferably not a plastic one, with a surfacepiercing drive.
Maybe something like this: https://www.rcgroups.com/forums/show....php?t=1348756

Keep in mind that everything you drag along under the hull is acting as a break and the don't come bigger than the submerged prop...
The rudder is a necessary 'evil', as is the intake for the watercooling.

Speaking of which; those few coils around the can don't do very much to cool the motor down, the contact surface is way too small.
If the motor tends to get hot, you'll need more coils, preferably using heat conducting paste to increase the heat transfer and a piece of shrinking tube to press the coil onto the can, covering the nasty heat conducting paste, which makes ugly stains in your clothing (don't ask...).

If you have room for it, a full cooling jacket, where the water runs directly onto the can is much better.

I use Aircraft ESC's in all my boats, but I replace the heatsink with a watercooler; in your application the 160A may hold up, but it will get hot during the run, as the heat has nowhere to go in a closed hull (NO, making airvents is a bad idea, specially in a fast boat).

The 160A may sound like a lot, but the cheap Chinese ESC's are manufactured very bad and usually only 30% (or less) of the power fets has physical contact with the heatsink, significantly reducing the capacity of the ESC (to something of 40A+).

The light spots are where the fets came into contact with the heatsink:

It's worth to check this and flatten the fets into one plane by sanding, and while you're at it, add a watercooler.
This one is custom made, but they are commercially available:

A before and after picture:

Regards, Jan.
Dec 05, 2010, 09:51 AM
matt the cat
Thanks. a few questions though. where do I get this paste you speek of? and if I do heat shrink the coils onto the motor, wont the heat shrink stop the heat disapation from the outside of the can of the motor? It would seem to me that If I were to do this the heat shrink would in fact keep the coils closer to the can but would also insalate the can and coils not allowing as much heat to be disapated of the can. Kinda acking like a insalater? Oh! and watercooling jacket for esc. sounds great. does anyone have one they may want to sale to me or part with?
Dec 05, 2010, 11:25 AM
Boaters are nice people.
Hi Matthew,

I got mine here: http://www.dealextreme.com/details.dx/sku.4579

As for the motorcooling, if the heat shrink covers the motorcan, this means you don't have enough coil around your can.
For the cooling to be efficient, it needs to cover the entire can length.

Much better and less messy is a cooling jacket like this one:

The watercooler for the ESC is simple to make if you have access to a drillpress, the 6 mm aluninum is drilled three times in a U-shape, the bottom hole is closed by a bolt and two pieces of 4 mm aluminum tubing are glued onto it.

Or, you buy one here:
Make sure to get the right size, OSE has three different sizes.

Regards, Jan.
Dec 05, 2010, 06:22 PM
matt the cat
well i need to try to see if it even gets real hot Jan? I have yet to run the boat but the more I think about what you said about the prop being at the bottom of the boat the more I think about not putting alot of money into this boat and buying the Spartan VXL Brushless Boat with/2.4 RTR by Traxxas.I need to see how this boat does with heat? guy said it was no problem . so i will put his prop back on see what i get , then probly not be happy with the speed and by the spartan from here.http://www.horizonhobby.com/Products...ProdID=TRA5708

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