Mean Machine Catamaran (Sport)

[Brushless55]

sweet, that's fast..

[D&D]

I started a new thread in the Boat Building section this morning concerning my boat.

But, yes, this morning I ran the boat first with an X440-3 with the struct even with the bottom, "O", and I ran 57.3mph. Oh, I also set the COG way back, I was running much further forward than anyone I had seen in this form, and it was a little flighty even with the 3 blade. Next, I ran a X442 with the same settings and it ran 56.3mph just before it lifted off and crashed. I will move the COG a little forward after that experence, but it seem as though this morning told me that the Neu 1515 1Y is more of an rpm motor thana torque motor - it likes smaller props.

[Brushless55]

Are you going back to 0 setting on your strut depth to see how it runs?

[D&D]

Initially when I ran the X440-3 my strut was just less than one-quarter inch up, results: 54.4mph. Same location for the strut with the X442 results: 55.5mph). Then when I ran the X445 my strut was just under three-eights inch up, results 55.0mph. I always ran my nitro boats with the strut flush with the bottom of the boat and proped or work props to that setting. Therefore, that is were I am going back to at this point in time.

I actually don't know the measurement of my COG, but I know it is over 10 inches from the transom of the hull. However; I'm going to move the COG back to somewhere around nine and one-half inches from the transom - I'll find out if I can get more lift without blowing over. That should be "fun".

[Rich]

I am new to FE cats too, i have an FE mini mono. I was wondering if you could tell me where your strut was when you ran the X440 and the X442? And where your COG was?

[D&D]

Back in the 80s there was a documentary TV show on the Australian who still holds the world’s water speed record and in that show it showed him cutting off his rudder to gain more speed. The following week there were more inches cut off rudders than in the history of the Capitol RCers club. I never saw much or any difference in the handling of a cat boat and with no GPS or radar (in our club) it was hard to tell about speed.

My rudder is 2 and three-eights inches under the running bottom of the boat and and is straight up and down. It seems to handle fine, but remember I’m not in a race and am building the boat for sport (just can’t stand to go slow).

My batteries are 4S Turnigy 5000mAh, 35-45C, and weigh 554g. I seem to run them well forward of other MMs I see on the OSE Forum. In fact my COG is well forward of other MMs, but it seens to really lift and the attitude of the boat looks great.

As I have stated previously, I am a FE beginner, I've tried to take advice from the forum and boats like "Fluid" "and Nautiboyz". I put that advice into what I bought and the care I took about starting prop sizes and watching my temps carefully, but I have no idea how many amps I'm pulling or anything else electric.

I'm not so sure I agree (or understand at this point) about prop sizing. Normally, my past experience says (if the motor can turn it) larger prop faster speed, but I've run as fast or very near the same speeds with a X440-3 as with a X445 prop. In fact my next move (when the weather clears up) is to go back to the X440-3 with the strut level with the bottom of the boat.

[Rich]

ok so you trimmed it, i might have to take more off of mine, i noticed that the longer one is thicker than the mini. Can you tell me how much your pack weigh each in grams? I was thinking about getting some 4s packs. And can you tell me how far the bottom of the strut is from the bottom of the sponsons and what angle you have it at? I can't seem to hit over 50 with out the amps getting too high!

[D&D]

It was 6" long but now it is 4&1/2" long. I love cuting things down and filing things by hand, seem to handle OK - BUT I don't go racing.

[Rich]

which rudder are you using the long 6" one or the mini 4" one?

[Brushless55]

D&D, Great looking MM!

[D&D]

Yes, two 4S packs in parallel (4S2P). The rudder and strut are Speed Master 21s.

So far I've run a X440-3, X442, and a modified X445 with the strut at different heights and I can seem to get away from 55mph (54.5 to 55.5). I havn't done that much testing yet, but I am somewhat confused by the consistency of the mph. This is my first FE but I have built a ton of nitro Areaomarine cat boats, oh well, testing continues today if weather permits.

http://forums.offshoreelectrics.com/...pictureid=2000

[Rich]

Nice i like it! so your using two 4s packs wired in parallel? And which rudder are you using?

[D&D]

This is my new MM build, my first FE build:
Neu 1515 1y
Castle Hydra HV 180
Futabe PM3-X FAAST
Turnigy 4S-2P (5000MA @ 35-45C)

First Run water way too rough ran slow and discovered a couple of minor problems. Second run on X440-3 GPS @ 54.5mph. Third run on X442 GPS @ 55.5mph. Temps acceptable and the boat is running like it is on a rail - which is not to say I would go racing, but it is a nice sport boat at this point.

Don't know if I am posting the pics correctly, but here is my try:

[IMG]/http://forums.offshoreelectrics.com/album.php?albumid=196&pictureid=1997
[/IMG]http://forums.offshoreelectrics.com/album.php?albumid=196&pictureid=2000

[Rich]

I ran the MM a few times with different setups,

First: grim racer prop 53 x 40, mini rudder, strut all the way up, 11.1 lipo

esc temp 119f, motor 83f

96 Amp, 1100 watts 36mph

Second: grim 53 x 40, mini rudder, 4s

esc temp 135f, motor 92f

166 amp, 2266 watt 43mph

Third: m445 prop, mini rudder, 11.1 lipo

Esc temp 138.5 f, motor 81.3

148 amp, 1675 watt, 45mph

Fourth: m445, long rudder (trimmed about 1" off) 4s, strut still all the way up with about 1 deg angle

Esc temp 182f, motor 96.7f

Amp 181.67 (WOW!) 2578 watts (WOW AGAIN) and the fastest speed yet 48mph!!

Just to let you guys know that i didn't do these in this order and the hull was well out of the water with these setups , but i do have a question on what i should have my etti 150 set to in terms of PWM with the 580 6l and the timing????

[Rich]

Well I fixed the flex tube problem, had to do some cutting and moved the water cooling jacket back to be able to move the motor down, I am happy with the way it came out. I will try it at the end of the week, ill let you guys know.