Mean Machine Catamaran (Sport)

[txboatpilot]

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

Reddy, I built a twin cat with 2/SV27 motor and esc combos. The hull is a Skunkworks 30" cat.. I ran it on 2/4S1P lipo's 3700mAH, they are about the same weight as 14cells... I put the gps in with CF45's counter rotating, and got a best of 33 mph.. I have s&b x447's to try, but I think with all the extra weight it needs a higher KV motor.. I am switching the motors out to Ammo 36-50-2300's to see if that will get it over 40mph?? I have other props, so I can always go down.. Here is a the thread on the twin..http://forums.offshoreelectrics.com/...ead.php?t=2400

[ReddyWatts]

I was going to run it on a single lipo for both motors in parallel, since they use around 40 amps each. Half of the weight. 4S1P. I thought that was the big advantage of using SV 4-pole motors. I would not give up on it yet, it just does not add up.

You really need to adjust the struts on the twin. On Robby76's first run with his 2-10XL, 2-16 cell twin cat was running 32 mph, then he adjusted his struts for a big increase in speed. It ended up going 43mph in a 42" 12 pounder. It is a cool sounding boat.

Use bigger props. ABC props has a better selection of L/R props.

Play with the CG.

The twin props should turn inward for more speed.

[txboatpilot]

The weight savings wont be enough to offset the weight of the Hull...IMO.... M/M are heavy hulls compared to most DF, H&M, and skunkworks.. I would like to see you try it, but even with 4S1P, i dont see it doing more than 35mph with x447's... I will run a 4S1P in the SK-II, just too see what the gps says..

[SJFE]

The hull Mr Watts is refering to is almost 40 inches if my memory serves me. You should be mid to high 40s on a 30 cat around 10 pounds with your setup easy. Heck my Jolly was mid 40s on 16 nimh @ 8 pounds 5 inches longer than the MM.

[ReddyWatts]

I would be interested in buying the two SV motors.

[txboatpilot]

The hull Mr Watts is refering to is almost 40 inches if my memory serves me. You should be mid to high 40s on a 30 cat around 10 pounds with your setup easy. Heck my Jolly was mid 40s on 16 nimh @ 8 pounds 5 inches longer than the MM.

I thought Reddy was refering to the M/M.. It is 29" long...

[txboatpilot]

I would be interested in buying the two SV motors.

I am going to hang on to them until I get another Ammo 36-50-2300...

[SJFE]

On Robby76's first run with his 2-10XL, 2-16 cell twin cat was running 32 mph,

I didn't know Rob had a MM. The only cat I ever seen him run was his big old kyosho conversion. I will have to look him up cause now I'm confused..lol...Like thats a rare thing hahahahah.

[Fluid]

It can be confusing trying to compare two different catamaran hulls, even with the same approximate lengths. The design of the tunnel and sponsons can make a huge difference in speeds, even with the same motor/cells. Too, how high do you fly the hull when making "speed" passes? Wet sponsons versus running on the last few inches can mean 5-10 mph more speed.

I have never seen a Skunky hull, it may be a great design or it may be stinky. The MM, while heavy, has excellent design features and can carry the weight very well with enough power. This is due to the wide tunnel, the tunnel entry and the sponson bottoms. That weight helps in rougher water, which is really the cat's forte anyway.

Tx, how is the attitude of the cat when making passes? Is it flat, or is it runing on the back of the sponsons? Your speed with the CF45s is about right for a boat that is running tight. Try to fly it higher and see if the speeds increase. Move the CG back and angle the drives with 1-2 degrees up at the back end - do it with the boat on a flat table, not "by eye" just holding the hull. If turning is compromised, just chop the throttle for an instant as you begin the turn, then feed in throttle. That will drop the bows and let you turn tighter.


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[txboatpilot]

Wet sponsons versus running on the last few inches can mean 5-10 mph more speed.

I have never seen a Skunky hull, it may be a great design or it may be stinky. The MM, while heavy, has excellent design features and can carry the weight very well with enough power. This is due to the wide tunnel, the tunnel entry and the sponson bottoms. That weight helps in rougher water, which is really the cat's forte anyway.

Tx, how is the attitude of the cat when making passes? Is it flat, or is it runing on the back of the sponsons? Your speed with the CF45s is about right for a boat that is running tight. Try to fly it higher and see if the speeds increase. Move the CG back and angle the drives with 1-2 degrees up at the back end - do it with the boat on a flat table, not "by eye" just holding the hull. If turning is compromised, just chop the throttle for an instant as you begin the turn, then feed in throttle. That will drop the bows and let you turn tighter.

I run in a oval mostly, no straight line stuff.. I like to practice in my local ponds, as if there were a oval course..Skunky was running on the last 5-7" of the sponsons.. I will try your tips! My first test run was 33mph and I did not have a lipo warmer! My lipos were cold, I am going to pick up a heater to pre-heat them next time..

[SJFE]

Pay close attention here TX. Mr Fluid knows his cats. I used this same advice and while my strut is not ajustable I did grab a hand full of speed from proper CG and flying my hull. I tucked my ruder under full to help with my corrnering. I wish I would have held on to my MM..It just happens to be the one Mr Watts has . If I ever attempt twins again the MM will be the hull.

[txboatpilot]

Pay close attention here TX. Mr Fluid knows his cats. I used this same advice and while my strut is not ajustable I did grab a hand full of speed from proper CG and flying my hull. I tucked my ruder under full to help with my corrnering. I wish I would have held on to my MM..It just happens to be the one Mr Watts has . If I ever attempt twins again the MM will be the hull.

I always listen too everything Jay has to offer! I have a M/M already that has Jay's set-up.. I run it with Nue 1515/1Y (2200KV) and MGM 16024-3s hydro.. on 4S2P 3700's 25C.. With a M445 this thing FLYS (50+ on the GPS)and is one of my fleet that I will not sell!!

The Skunkworks hull is just for FUN, I really like the dual props!!

[Flying Scotsman]

[QUOTE=SJFE;26293][B][I][COLOR="Navy"]Pay close attention here TX. Mr Fluid knows his cats.

No kidding Tom. Thanks Jay for your advise and also Reddy.

Douggie

[ReddyWatts]

This is the setup I would recommend now for a fast sport Mean Machine build. It could be upgraded with lipo's to run in the 50's as txboatpilot states.

Neu 1515 1Y 2200 kv
12 NiMH cells IB3600
NiMH.150/Lipo .187 flex shaft
X640 prop 25903 rpm 76 amps 930 watts 48mph NiMH
X642 prop 24780 rpm 88amps 1000 watts 49 mph NiMH
atleast a 120 amp controller on NiMH's.
Use a 200 amp controller on lipo's and larger props.

[rcflyer55]

All the parts ordered, Hull sitting in my workshop. Still need to get Lipos. Will start building(installing) next week hopfully.

Thanks for all the help Fluid & ReddyWatts(and the build thread)

everyone has made a FE newbie feel welcome(and not so dumb).

I'll do my best to get through the rest on my own.

MM .18 Hull converted
Feigao 10XL
Hydra 120
Speedmaster Hardware
asst hardware all from ReddyWatts build
Batts undecided (probably TP ExtremeV2 4S2P 3850mA or 4500mA)