Mean Machine Catamaran (Sport)

[Rich]

What rudder should i use with the MM? the speedmaster mini or the 6" one?

[ozzie-crawl]

from what i have heard people have had turning problems with the mini on theMM, i run the 6" on mine and it turns like its on rails

[ReddyWatts]

I would use a rudder longer than 4" if running over 40 mph.

[Rich]

so this one it is then? pt# ros-21-rudder Speedmaster 21 Rudder Assembly 5.25" Long

[Chilli]

That's it. With the 1.5" setback.

http://www.offshoreelectrics.com/pro...=ros-21-rudder

[Rich]

here it is!!!!

ok gentlemen here it is a mean machine with a 580 6L, m440 prop, 6" speed master rudder and strut, .150 cable, 150 amp etti with 35v cap, 6.5mm bullet connects, and 4s 8000 mAH lipos. Speed 40 mph, amps on first run 150.53 2007 watts, hull was a little wet, 2nd run moved the strut up about 3/16" with a degree or two of angle, speed still 40 mph, amps 141.87 and 1851 watts better, but i still think it has more, temps esc 155f, motor 86f, per eagle tree elogger V3. I will try moving the lipos back more to fly the hull, are there any other suggestions to make it faster?

[Fluid]

The first problem is the prop - it's too small for that motor. Try an m445 or m645 and see how it runs. The overall setup looks good from the photos, but a few questions:

- Exactly where is the CG now?
- Set the boat on a flat surface - where is the bottom of the strut relative to the sponson bottoms? What angle?
- What timing advance are you using on the ESC?
- How much gap between the strut and the drive dog?



.

[Brushless55]

second could be the rudder is huge..
I would take 2" off

[Rumdog]

The man machines dig a long rudder. I'd keep it!

[Brushless55]

I don't know man, I have a 4" on mine and it turns sharp and hard
I think the extra could cause the bow to pull down and make the hull run wetter?
140+ amps and only 40mph

[sailr]

you're gonna demagnetize the Feigao at those temps and then it will destroy your esc. Ask me how I know!

It looks to me like way too much weight in a MM and way overpowered.

[blackcat26]

I'd run the cooling tubing to the speed control first then motor.....It takes #1 priority on being cool, motor second.

[Rich]

The first problem is the prop - it's too small for that motor. Try an m445 or m645 and see how it runs. The overall setup looks good from the photos, but a few questions:

- Exactly where is the CG now?
- Set the boat on a flat surface - where is the bottom of the strut relative to the sponson bottoms? What angle?
- What timing advance are you using on the ESC?
- How much gap between the strut and the drive dog?



.

Fluid you are the one i was hoping would answer since your neu mean machine was my inspiration for this project . I want to hit 60 tops, but 50 to 55 would be ok if 60 is not possible.

>Anyway i have attached some photos of my CG, the center line of the batteries are just behind the 9.25" red tic mark which is 33%

>The bottom of the strut is actually 3/32" from the bottom of the sponsons not 3/16" like i had stated before and the angle is about 1.5 degrees. I can't move the strut much more with out having to bend the stuffing tube again as you can see in the pic.

> I am using a timing of 1 deg since this more is a 2 pole motor.

>As for the gap i used 3/16" for the run that pulled 150 amps, i notice some water in the hull and added a piece of fuel tubing b/t the drive dog and strut, I raised the strut and the amps were 141 i know that there needs to be a gap, but i don't have enough cable length for it with the fuel tubing thought i still have a leak somewhere...

As for you prop suggestions, wouldn't i gain amps if i switched to a bigger prop? After I raised the strut for the second run i noticed that the prop cavitated up until just after1/4 throttle and the thing took off!

Fluid did you shorten the rudder on yours like the others down below have suggested?

Thanks everyone!!!!

[Rich]

here are the pics

[Jeff Wohlt]

That stuffing tube bend is EXCESSIVE! There is some of your problem...you are going to eat something up like that...probably the cable and the tube.

If you are pulling those amps you have issues. You should be in the 80-100 amp area. I am running a X442 and only warm after dumping the cells.