Thundercat 31 conversion questions

[jjaj]

I have Proboats 31" thundercat that I am converting to brushless. My setup includes; Fieago 580L 9T, 150 etti w/o bec esc, 2-3cell 4000mah lipo batteries, octura x648 prop. I have tried starting with the grauper 40mm prop and worked my way up from there. The prop I have on now is the best Ive tried. My runs are 40mph. The last time I went out and ran, I noticed my wire harness and my connectors(deans) were extremely hot. I was told that deans connectors are only good for 60amps or so. Im trying to post some pics of it, but Im not sure how to. With the power system I have, I thought I would be running in the 50's. Can someone help me figure out what Im doing wrong?

[Fluid]

While I have no experience with the 580 motors something does not make sense here - you should be closer to 50 mph. Hot connectors makes sense as you are likely pulling well over 100 amps with that setup at that speed. Change to 5.5mm gold plugs at a minimum. Shorten your wiring as much as practical. Your cat may be running too wet, where is the CG from the rear of the sponson bottoms? How far above the sponsons are you running your prop? Is the driveline smooth? How hot are the connectors - is the solder melting?

Where in LA are you? You should come over to the HOTMBC meeting on the 18th in Katy Texas, we'll get you running.



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[Steven Vaccaro]

I have Proboats 31" thundercat that I am converting to brushless. My setup includes; Fieago 580L 9T, 150 etti w/o bec esc, 2-3cell 4000mah lipo batteries, octura x648 prop. I have tried starting with the grauper 40mm prop and worked my way up from there. The prop I have on now is the best Ive tried. My runs are 40mph. The last time I went out and ran, I noticed my wire harness and my connectors(deans) were extremely hot. I was told that deans connectors are only good for 60amps or so. Im trying to post some pics of it, but Im not sure how to. With the power system I have, I thought I would be running in the 50's. Can someone help me figure out what Im doing wrong?

What props did you used in between the graupner 40 and x648. I would estimate the x648 is to large. As Jay said you will be pulling way more than 100 amps with that prop. Probably more than that and out of the efficiency range of the motor.

[lomdel]

Please post some inside pics of your set-up! The TC31 hull is a rather heavy hull with all the wooden stringers. Take out all you can, like the radio box and cut away some non-essential plywood stringers... Start with a M545 or X642 prop and replace all connectors with 5,5mm bullets and ensure proper cooling of everything.

[jjaj]

[ATTACH][ATTACH]boat pics 019.jpg[/ATTACH][/ATTACH]Here are the pics;

[Christaphason]

Here is Jjaj's TC31 brushless

http://www.youtube.com/watch?v=P_afFVRbp3Y

Not the greatest video but, i guess its better than nothing.

[jjaj]

(fluid) The CG is 10 1/2" from the rear of the sponsons, the flexshaft is even with the bottom of the hull. (In the video I had the strut all the way up.) I have some 6mm bullet connectors on order as well as 10 ga wire to make my harness. The driveline is very smooth and easy to turn. The solder was not melting, but I could not hold the wires in my hand at all. As far as running wet, I dont think so, but Im not sure. Can you look at the video and tell me what you think? The overall weight of the boat with everything is 8 lbs. Some say to take out the radio box and all the wood that comes in the boat and fiberglass some areas to strenghthen it but that would only take out about 1/2 lb or if that .What kind of differnce would that make, Is it worth it?

[Fluid]

While it's tough to tell from the video angle, I believe you are running pretty wet. Another problem is all the acceleration from a dead stop - that generates a LOT of heat. One reason some folks can make a setup work and others can't is the way the boat is run. Keep it on step and near full throttle and you will draw a lot fewer amps than if you are constantly stopping and starting. On that small pond, limit your run time to control temperatures.

First, replace the plugs and shorten the wiring - I don't like the extensions on the battery leads.

Second, move the CG back to about 9" ahead of the sponson transoms. That may be too much, but is probably close. If you blow it over, then you'll know. Moving the CG back will reduce the hooking too.

Third, raise the strut so that the bottom of the strut is about 1/4" above the sponson bottoms. Angle the strut up 1 to 2 degrees at the prop end - put the boat on a flat table, don't try to "eyeball" it.

Eight pounds is a tad heavy but not that bad really. My 4S Sport Hydro weighs almost 10 lbs but races great. Cutting out weight would be the last thing I'd do.


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[jjaj]

Thanks, Ill try that and see what happens.

[jjaj]

Well I set the CG to 9" from the back of the sponsons, and set the strut 1/4" above the sponson bottoms and set it at 2* up. The boat appeared to be alot faster, but it wants to flip at full throttle. I tried lowering my batteries and also took out the radio box, but it starts to "dance" from side to side until it is uncontrollable and rolls itself. And after 5 times of doing that, the canopy couldnt take anymore, and broke. I am thinking that before I burn up my electronics, I would rather buy another hull that can handle the power. I was looking at the 32" cat that "Head Of The River" sells. Does anyone know if this would be a better hull for my setup? Any other suggestions? Also, On the etti 150 esc, what should I program the PWM option to? Again my motor is the feiago 580L 9T.