Micro 12" wooden boat build

[kfxguy]

So I decided to gps it (lmao!) and it did 17mph. I think it would actually go about 20 without the gps because I had to mount it on the front and it was running real wet, but was funny nonetheless. I think I could actually rinnthe prop a little positive from neutral where it's at right now. Running the motor with no cooling is proving to be a bad choice on my part but hey....for tom doing a little boat like this. I ran the batts to 3.78v per cell and the motor was pretty dang hot. Esc wasn't even warm. I checked the motor temp a few minutes after I got back to my camper and it was 156f! Lol. Time to make a cooling jacket.


MIMG_8923.jpg

[NativePaul]

It will do something, but don't expect the motor to respond to cooling as much as normal those Align outrunners in cans are a bit of a weird design and the can isn't in contact with the windings like an inrunner, or even the magnets like a brushed motor. You may end up with a cold can but little difference internally.

[Jesse J]

Sounds like time for a little bigger inrunner, Travis. I'll post specs on the one I'm using.

[srislash]

I have a few little inrunners here Travis, you are welcome to one. But remember the outrun era do run hotter and are designed for it. Maybe a little fan?

[kfxguy]

Lemme know what you have Shawn. The measurements on this motor is 28mm diameter and 28mm long (can only). I could go to maybe 30mm long in the diameter is smaller. Maybe a little longer. I'm running a 1200mah battery right now but I have a smaller 800mah one too. This motor is 3900kv.


I made some changes that should help it run cooler.

1) sharpened the rudder. Less drag
2) flattened and smoothed the sponsons with sanding block
3) got rig of that humongous prop nut (all I could find when I was getting it together) and put one that's the same size is the prop barrel. Just to give you an idea the prop barrel is 6.26mm and the nut was 8.9mm in diameter. Not too conducive for water flow around it.
4) I put a small sheet of carbon fiber under the rudder bracket and steering linkage. You could see a stream of deflected water bouncing off something in that area, causing a lot of drag. that should help it.


I'm charging batts right now and I'm gonna got to the lake shortly. I bet I get over 20mph out of it. Lol

[kfxguy]

Ok ran it again. 18.4mph this time. Not much gain for the effort lol. I was mistaken that the rudder was causing the water to shoot up, it was the strut. Learned something new I can apply to my faster single cats. Stay tuned and if my idea works I'll share it with you guys.

[kfxguy]

Ran it once more. Didn't pick up much speed but the spray of water is gone and it handles much better. I think it could handle 3s. I may bump the kv down and go to 3s. It ran 18.8mph but with the gps on it it slows it down noticeably. It's kinda heavy sitting on top front of it lol


Here's a video

[kfxguy]

I had to edit the first post. I had the kv wrong. The motor I have is 2800kv. Doh! Lol so I'm only Turning 20k rpm lol.

[srislash]

Ok well I don't think I'm of much help to you. I have a Velinion VXL which would be 28mm x 45 and 4000kv, a Leopard at 28mm x 47@ 4700 KV and a 25 mm x 45 at an unknown KV. Think it was a 2s in a NQD

[kfxguy]

Man I don't know what to do at this point. I was thinking about going to a 27mm prop and maybe 3s but I can't find a 3s pack that will fit. I'll keep searching. I need to pay attention how much mah I put back in the battery after I run it, this batt I'm running is elcheapo no name and it may not even be 1200mah like it says. I can't find a higher kv motor that will fit either.

[srislash]

Ran it once more. Didn't pick up much speed but the spray of water is gone and it handles much better. I think it could handle 3s. I may bump the kv down and go to 3s. It ran 18.8mph but with the gps on it it slows it down noticeably. It's kinda heavy sitting on to of it lol


Here's a video

You gotta love the little ones you can take camping with you and toss in the water.

[kfxguy]

You gotta love the little ones you can take camping with you and toss in the water.

That's the whole purpose of this boat. I actually want about 25-30mph out of it, zip around a small pond and can put it in a small case so it's easy to bring and setup. Having to bring a big ole battery charger and tools and all the other junk to run a boat just isn't fun anymore. I need to find a small cheaper I can use for 2s and 3s receiver packs. Any ideas?

[srislash]

I have the little DF mono, and did have the NQD('s). But George took care of those plastic hulls. Damn sharp teeth!! Haha. And them hulls aren't $50 cheapie anymore.

[NativePaul]

Could you fit in a 28x29mm motor? if so maybe consider the Mega 16/7/x motors, the 16/7/3 5580kv and the 16/7/4 4420kv for 2s, or 16/7/5 3450kv and the 16/7/6 2850kv for 3s. As the 16/15/2 and 16/15/3 I run in my 450mm 500g mini hydros and cats run so cool (water cooled) I have thought about stepping down to the 16/7/x motors to save weight.

[kfxguy]

Could you fit in a 28x29mm motor? if so maybe consider the Mega 16/7/x motors, the 16/7/3 5580kv and the 16/7/4 4420kv for 2s, or 16/7/5 3450kv and the 16/7/6 2850kv for 3s. As the 16/15/2 and 16/15/3 I run in my 450mm 500g mini hydros and cats run so cool (water cooled) I have thought about stepping down to the 16/7/x motors to save weight.

Yes that would fit. I looked those up and that little thing is $81, is that right? Little more $$$ than I care to spend on this thing right now lol. I did fin some 3s receiver packs that would fit, so I think propping down and more voltage would do it for me. Much cheaper route too.