Making an outrigger boat kit available for $35 shipped, need input!

[slowsl]

[slowsl]

[slowsl]

Here is what I have planned for the larger version. It will have T-nut connections for the aluminum arms & turn fin, so you won't have to worry about stripping them out.

[slowsl]

Okay, minor setback....
I ran an oval balls out, non-stop through an entire battery pack. After checking the motor, it was way too hot. Battery pack was pretty hot, however it is only a 35C, I guess that is borderline asking for trouble. My log showed a peak amp draw of 90amps if I remember right, the motor is rated at 61amps max. Nothing seems to be binding up, water seems to be flowing through the jacket, etc. I had the smaller 1938 prop in. I can't see the prop being the problem, I mean hell, even the UL-1 motors are turning a 46mm x 72mm pitch prop. Any ideas? What should my timing be on the motor? It is set to auto via the swordfish pro ESC, but It does allow for adjustment. Motor is a leopard 3650, 4-pole.

[siberianhusky]

The Ul-1 motor is also running on 4s - huge difference.
Lower voltage = higher amperage for the same power (watts).
All things being equal if it takes 60 amps for a 4s setup to turn a given prop it will take 120 amps to turn the same prop on 2s at the same rpm.
I built my JAE 12 from the plans, it is a very light boat, flies on a .12 air cooled car engine running 35% nitro and a x438. Some people build heavier boats than others I guess. Hull, all the hardware and the 2 servos weigh in just over 1 pound, that is less the nitro motor for mine.

[slowsl]

The Ul-1 motor is also running on 4s - huge difference.
Lower voltage = higher amperage for the same power (watts).
All things being equal if it takes 60 amps for a 4s setup to turn a given prop it will take 120 amps to turn the same prop on 2s at the same rpm.

Right, but I'm running a 4s battery..... I don't see where the heat is coming from, or how to even begin finding out. Guess I should start by making sure it's cycling water through the system.

[TRUCKPULL]

You said that you ran non-stop through an entire battery pack.

For racing - 1 lap mill, 6 lap race, 1 extra lap incase you cut a buoy.
8 lap max on a 1/6 mile oval

When you run your batteries down below 50% - you will start to build more heat in the packs and motor.
You will also get more heat just from running too long.

Larry

[slowsl]

You said that you ran non-stop through an entire battery pack.

For racing - 1 lap mill, 6 lap race, 1 extra lap incase you cut a buoy.
8 lap max on a 1/6 mile oval

When you run your batteries down below 50% - you will start to build more heat in the packs and motor.
You will also get more heat just from running too long.

Larry

Thanks Larry, I guess I was under the impression that a properly setup boat will run through an entire battery without overheating. It makes sense to optimize for heat racing or saw racing.

[MarkF]

slowsl

17,19 and 20 series props are saw props. Not oval. Stick with 438, 437 and maybe 440 size prop for run time and less heat. Also boats aren't made to turn left. Right turns only with a little bit of left for corrections.

Mark

[slowsl]

slowsl

17,19 and 20 series props are saw props. Not oval. Stick with 438, 437 and maybe 440 size prop for run time and less heat. Also boats aren't made to turn left. Right turns only with a little bit of left for corrections.

Mark

Gotcha, I went ahead and got an x438 & x440 to test with. I've been digging and digging through build threads, videos, etc. and it looks like I've reached the leopard 3650's wall. The boats that I see that are reaching 60+ mph are either larger leopards, or a NEU (still larger than the 3660), motors that are around 1,000 watts or more. the 3660 is only rated at 800watts, most likely a generous rating from Leopard. I'm thinking I'm already pushing past its safe limit. I'm going to be upgrading to a Neu 1512 or 1515 in a couple weeks. I should be able to spin the larger props without building as much heat, in theory.

[slowsl]

Finally went with a Spektrum dx4c, finally, problem free. I switched to the x438 prop, and adjusted the front sponsons to 3.5 degree. I haven't yet fabricated a table in order to accurately check my angles, so the strut may be a little off. I found there was too much slop in the way the sponson adjustment plates mounted to the booms. This would allow the boat to lift too much around the corners, even in the straights. It handles much better now. I'm having some made via a 3d printer, which the booms will slide into, and keep it completely tight. I'm getting some high frequency hops still, should I first adjust the strut angle to plant the rear end a little more, then adjust the rudder rake to take care of any hops around the corners? Take a look at the video to see the last run.

I've also noticed that my battery gets pretty hot, but the wires & connectors even more so. They are almost untouchable. 3.3A*35C=115A safely, the logs show a peak of 90, and the motor is rated at 61. Something doesn't seem right here. I've read that the motor will not be starved of amperage, but rather the battery will deliver at an unsafe level and fry out, I'm not sure I'm buying that completely. There has got to be some efficiency lost somewhere. I'm going to buy a better battery w/ a higher c rating and see if that helps.