Mean Machine Catamaran (Sport)

[ReddyWatts]

Final setup on Mean Machine (Sport)

I used a M640 prop on the final setup of the Mean Machine (Sport) using IB3600 cells.
(Use the Y537/3 prop on sport cells at 50 amps.)
14XL Used 70 amps on 24 - NiMH IB3600 batts.
Raised the strut up 1/4 inch above the bottom of the boat.
Water cooled the motor and ESC.
Gained 5 mph when switched from sport to IB3600 cells, also jumped 10 amps.

[NorthernBoater]

Does anyone stock the m640 prop.

[ReddyWatts]

I trimmed the tongue on a X640 to make a M640.

[Tunda]

Fluid let me know when you want to sell it..............

[hammertime]

fluid are you using one of those mini t ib packs to run you servo??

[Fluid]

Yes, a 5-cell IB1200 pack. Runs forever even when I forget to turn the receiver off for a few hours......:p


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[ReddyWatts]

I think another cool "sport" setup for the Mean Machine would be to install two Super Vee motor/esc combos with a dual prop drive (X447'S) on one set of 14 cell NiMH batteries. It should run in the mid forties. 50's on 4s lipos???

The 2 - 6 pole motor setup should be very reliable. Use a little longer rudder than normal.

http://www.offshoreelectrics.com/pro...d=dh-blcomboaq

[Craig]

These 3300 cells have been ok. They are not close to the quality of the IB cells. My next set will be IB cells for more speed, but they do fine on the 14XL or a 700SC for sport running. I would not use them on a 12XL to 7XL motor.

Why wouldnt you use a 12-7xl motor with this many cells? How about a 12xl with 21 ib cells? C

[Craig]

I am going to go brushless. I keep getting told you cant run 21 cells on a 10xl in a 36" boat. Would that over volt the motor? Is the boat too big? Help me out please. C

[Steven Vaccaro]

The boat is to big. You either need a physically larger motor. Or a lower rpm xl feigao which will give you more torque.

[ED66677]

Craig, a 10XL under 21 cell will spin more than 41000rpm and give a max power of 1660Watt at 66amp, witch is enough, if you need more power you need to use then a 9 or 8XL, less turn more amp and higher KV, but increasing cell count increases rpm you will then reach a situation where you spin fast, drain many amp, but spin a very small prop, if the prop is too small it won't be able to transfert the 1660watt from the power plant to the water, a reasonable (as far as I know) slip between prop and water is around 15%, this mean a 2" pitch prop will move a boat of 2" minus 15% of 2" (hope my frenglish is clear enough), in this particular case the slip will considerably increase 30-40% (I guess), so you will have plenty of power but will only waste it, because the prop is just not able to!
So you need a bigger prop and the only way with a 10XL under 21cell is to use gear

As steven said use a bigger motor KB45 8XL that has a lower KV but a lot more torque, you will avoid the gear, and you'll have the possibility to double the available power... and so for 10 extra bucks!

[Craig]

So the smaller the number 8xl has more torque than a 10xl? What is the max you can spin an xl motor? C

[ED66677]

No Craig 8XL has less torque than 10XL
Max rpm is 50000 and 70000 with ceramic bearing

[Rex R]

bump (suggestion, sticky this thread)

[ReddyWatts]

Results of the 60 mph Mean Machine setup.

Fluid

I run the 1521/1D in my Mean Machine spinning an m440 on 4S and it does ~60 mph for 6 laps on a 1/8 mile course. Nothing gets very hot, and it uses around 3600 mAh of capacity. It certainly does not draw 200+ amps, its closer to 125 amps.