D&D's Mean Machine Sport

[D&D]

I decided that I wanted to build an Aeromarine cat boat again and the community that requires only electric boats of any kind. I have 13 years experience of building nitro cat boats, but zip nothing about eletrical anything. I looked around and first ordered the $60 MM from Aeromarine, then sent it back and ordered the MM built by Areomarine with extra carbon fiber. There are pictures of the completed boat in my D&D FE MM Cat album on this site.

I decided to aim for "Fluids" 61+mph even though I was not going to purchase as much motor he was running so here is my build:

Boat: MM Cat (American version)
Motor: NEU 1515 1Y
Controller: Castle Hydra HV 180 (set at "normal"/2 setting)
Radion System: Futaba 3PM-X FAAST
Servo: HiTech HS -5445MG
Hardware: SpeedMaster sport 20
Battery: Turnigy 4S2P, 5000mAh, 35-45C

My first runs using a X440-3, X442, & X445 props set from one-quater to three-eights of an inch up were all in the range of 54.4 to 55.5mph. I tried these props and strut setting based on what I read in this site but did not understand the almost identical speeds with that range of props.

This morning I decided that I was going to go how I always did on my nitro boats, the struct was always set even with the botton of sponson (no positive or negative) and I sized props and or modified props to work at that setting. I did that because I felt the boat handled best and all I did was race.

This morning I ran the strut as stated above and my first run with the X440-3 was 57.3mph. My second run with a X442 was 56.4mph, but the COG was too far back and it crashed. It seems as though this motor like higher rpm and smaller props. Your comments and recommendations please.

[Fluid]

The 61 mph I achieved was just goofing around, I never considered it to be a setup I'd run much at all. That speed with this boat requires smooth water and no wind!

Your results are stellar. Yes, the 1515/1Y is really a hydro motor, high rpm and smaller props on large draggy boats (non-hydros). You could try advancing the timing another five degrees using the CastleLink, that could give another mph or two, just watch for heat issues.


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[D&D]

Fluid, thanks for your reply.

I remembered from your post that you would not race the boat with your 61mph setup and I agree, I was flying on the edge with the X440-3 at 57.3mph. However, my racing days are gone (just can't stand to go slow) and I only intend to run for my own sport, but I still believe that there is more left in this boat. A little tweeking with the X440-3 and maybe even try a smaller prop and do some work with that. My Castle Link, as I rmember, only had four settings (timing/etc.) I am currently on two or normal and Castle told me that 3 was for SAW and 4 was almost for certain a melt down. I prefer to work with the current controller setup and play with props, strut, and Cog. I may not reach 60, but hopefully I will have fun and protect my investment.

[ReddyWatts]

Try a Y537/3. Smaller diameter with more pitch than the 440/3

[Fluid]

The newer CastleLink software allows you to set the timing at any value, so you could step up one degree at a time....or not. To go faster you will need more pitch like Ready said. For extreme speeds a v937/3 is the ticket, but that prop will require a different setup - lower strut setting angled up, CG back a bit, maybe 10-12 ounces of lead at the CG too. A 'similar' setup went well over 70 for me some years ago.


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[ReddyWatts]

Be careful with a V937/3. It has a huge jump in pitch from the 440/3

X440/3-- 2.198
Y537/3-- 2.279
X442---- 2.310
X637---- 2.368
X445---- 2.478
X640---- 2.512
X447---- 2.590
X642---- 2.640
M545---- 2.655
X448---- 2.660
X450---- 2.758
V937/3-- 2.812



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[Fluid]

Like I said, for extreme speeds...

BTW the 37mm props are not as efficient on that hull as the 40s and 42s so they will usually have higher slip values. At least they did on mine.


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[ReddyWatts]

I did see a little more slippage coming out of the hole in this hull using a Y537/3mm prop than an X440, but also saw more top end speed. Might get you over the 60mph barrier without stressing any components.

[D&D]

I'll have to look at those props (Y537-3 & V937-3), but I will be leaving for my home town in Indiana in a couple of days and don't have enough time to get them delivered. I will be home for 30 days, but there is a lake within my small town city limits and I plan to continue running there. Maybe I can order the props after I get home and work on them there. Thanks for the advice.

Today I plan to pitch up the X440-3 for a test run, I'll see how that goes. Also, when I get to Indiana I'm going to try detongueing the X442 and work with it too.

[DISAR]

You can also try bigger diameter props, 642, 645 better acceleration too. I think your amp draw is probably low with your setup. You can first try the 642 and check the temps after 1 min run. I run my MM with 1515 1.5Y, 6s2p, 646/3, 250A esc. everything is cool
Or you can go with 5s on the 440/3 or 442 (I run the 1515 1y on 5s with a 442 with turnigy 180A in a Maritimo)

[ReddyWatts]

Disar, what is the top speed with your setup?

[DISAR]

You know what, I can never achieve the speeds mentioned here. I always have 10 mph less, run in sea water with some chop always
I have achieved 52 mph, so in USA is probably more than 60. The 646/3 is the best propeller I have tested for the MM (440/3, 442, 445, 645, 646, 447, 648, 220, 225, 235), the 646/3 is the winner

[ReddyWatts]

That is interesting that top speed is with a 3 blade prop.

[DISAR]

and the 646 was very good as well, both props detongued, fast acceleration and best top speed.

The MM is a great boat, easy to build with your instructions and very very good handling

[Fluid]

Dimitri it is not at all surprising that your speeds in rough salt water are different than in fresh. The density and surface tension differences in the salt fluid are well known; full-scale racers seldom use the same props or setups in both fresh and salt water for example.

The fastest speeds with most any boat will be in calm conditions on flat water. The rougher the water the slower the boat for several reasons. Every time the hull hits a small wave it slows down a bit. The hull does not ride at a consistant aoa to maximize lift through air compression. The prop is never at a constant depth so its thrust is never optimal. With my smaller SAW cats I see higher speeds on flat water than on a ripple. Most of my SAW cat records and fast passes were with three-bladed props like the v937/3 and the x450/3.


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[ReddyWatts]

Why is that fluid? Theoretically a 2 bladed prop is more effecient.

[D&D]

I think I've proven for my setup that a smaller diameter prop is probably better. I have pitched up the X440-3 prop, reset the COG so that is not quite so much on the edge, and will change the Controller timing from 7 to 9. Will let you know how it does later today.

[D&D]

Oh, I ment to reply on my last about 3 bladed props. I usually ran three bladed props in my past life because I thought the boats ran smoother and better for racing. But on my 60 Sprint Cat is was definetly faster with a worked X455-3 blade, however; a Prather 260 or 262 was the clear choice for the 90 Sprint Cat. Bottom line, I actually think it os all about the exact boat you are running and it's all around setup. I can't quote sience to you, just the results from running many different cat boats.

[ReddyWatts]

I have experienced the same, just cant explain why. I am seeing large catamarans with 5 blade props. ???

[D&D]

Afternoon results disappointing. Strut flat with the bottom of the boat, COG a little forward from the 57.3mph run, timming up from 7 to 9. Results: X440-3 - the boat was bouncing until top end and that could have been the COG of my bad pitching on the blades 57.6mph. X442 - the boat liked the COG better and ran 57.0mph. Temps were up across the boat, it was very hot here today 92 degress, but it was probably the adjustment to the motor timming.

Results on the X440-3 may have improved some at a different COG setting. I'm going to trim up the X442 and try that, but I'm more hopefull about other props I will have to get after I get back to Indiana.

[Fluid]

Why is that fluid? Theoretically a 2 bladed prop is more effecient.

Theory is nice, but it is results that matter. Even the fastest full-scale boats usually use 3-bladed props. The two fastest FE boats in the world ran 3-bladed props to set their records.

We often have more power than we can get to the water, we need blade area to transfer that power. With two-bladed props you get more blade area by increasing diameter...but that can cause terrible prop walk which hurts top speed. Three-bladed props can have enough blade area without an excessive diameter.

Now two-bladed props can certainly perform very well, but they hold no real advantage because of some imagined "efficiency". Again - what works works.


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[ReddyWatts]

So, there is less slippage with a 3 blade when using high power and rpm on a surface drive?

[DISAR]

I don't know so much, but Fluid's opinion is very correct. I guess yes, 3 blade props have less slippage

[D&D]

I decided to set the controller timing back to "Normal/7" to cool things back down to preserve my equipment and ran the boat again yesterday. I moved the cog back and the boat ran beautifully at 57mph on the X440-3 prop, I really justed enjoyed the attitude of the boat it looked great.

I also ordered the Y537-3 prop and a backup X440-3 from OSE and will work on those props and test them back in Indiana. Anybody here from northern Indiana? Rochester is my home town.

[kevakov]

D&D, where are you setting the COG , I need to know for the Jagermeister MM I just finished?. I have heard that its anywhere from 8 to 8 1/2 to 9 1/4 . Guess it really depends on the exact weight of the hull with different motors and lipos that that have different weights to them. I'm going to start at 8 1/2 from the transome.

[D&D]

I started somewhere around 9 and one-half inches, but understood that the COG would vary widely based on the specific boat, batteries, and everything else mounted in the boat. I have been well forward of that with larger props and well aft of that with smaller 3 bladed props. Use it as a starting point, but be sure you built into your boat the capability to move the COG freely by leaving space for the batteries to move. In my example I built in a board and velcroed it the length of the hatch opening.

Good luck.

[Fluid]

The optimum CG will depend on the weight of the boat, its power level/speed and the strut position, but mine generally runs best between 8.75" and 9.25".


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[kevakov]

Thanks for the info, I'm hoping for mid to upper 50's for this hull.

[RIPFENCE]

great looking boat man...i am testing a mm myself but i do not have a good range of props to test with YET...i am curious about your x440 3 blade..i just bought one to try too

[Joe M]

Hi i just built mean machine with same set up motor 15151y hydra 240 prop m445 4s on the second run about one min. in to run blew one of the cap wright out of the esc need help thanks Joe M

[JMSCARD]

Hi i just built mean machine with same set up motor 15151y hydra 240 prop m445 4s on the second run about one min. in to run blew one of the cap wright out of the esc need help thanks Joe M

wow... thats odd... I run a 1515 1.5y with a hydra 120 on 6s all the time with a m445.... never any issues.... wierd, maybe your lipos caused it.... 4s with a 1y and hydra 240 should be a great setup???

[Fluid]

...motor 15151y hydra 240 prop m445 4s on the second run about one min. in to run blew one of the cap wright out of the esc...

IMO the 1515/1Y is not really suitable for the MM as a sport motor. It is a great hydro race motor, but if the MM does not run freely it will overload the motor and the ESC fails. If the boater keeps getting on and off the throttle, accelerating and decelerating cyclicly, the motor draws huge amps and builds up a lot of heat in the motor and ESC. Combine the two practices with a long run time and it would be no surprise that any ESC was smoked.

With a race motor like the 1515/1Y, the boater should limit his run time to 2-3 minutes maximum if he is running at a constant speed. If he is on and off the throttle all the time, 1-2 minutes may be better.

If the motor is drawing a lot of amps like the 1515/1Y can, the cells must be up to the draw. 'Ripple currents' are the drops in pack voltage during part throttle, high amp draw running, and they heat up the ESC caps fast. If the caps fail, the FETs are next. Race motors need high quality cells with a high mAh and high 'C' rating, or problems with the ESC can be expected.

IME better motors for 4S sport running of the MeanMachine are the Feigao 10XL for cheap cells, or the Neu 1515/1.5D for top quality cells. The former gives speeds in the mid-high 40s, the latter mid-high 50s. The latter will spin a big prop so have a good motor mount....


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[D&D]

I would have a hard time disagreeing with most thing that Fluid states. However, I will point out that when I talked to Castle on the phone they quoted to me that with the setup I have (1515 1Y, HV180, and 4S) that my batteries should proved a minimum of 8000Mah and have a good "C" rating. So far my Turnigy 4S2P setup at 5000Mah and 35-45C have done well with long run times and varying speeds (but, mostly flat out). I ran here in Indiana yesterday and ran the batterys all the way to the 12V shutoff point that I programmed into the controller. I recharged the batteries today and they seems to charge OK, I'll see when I run it next.

Yesterday I looked faster than H--- (like a half-inch of boat in the water and the bottom blade of the prop), but it only ran at 56mph - I think it was the different angle on the GPS satalite here in Indiana versus NC. I got my new Y537-3 prop yesterday and by this afternoon it was polished, balanced, and sharpened ready to go - at least 60mph right?

[ReddyWatts]

The Y537/3 calculates to be about 3 mph faster than the X440/3 using less amps. Good Luck!

[izzy7771]

D
it seems like i always struggle with gps signals in Indiana for me. a lot of time i run out of lake before i get accurate readings. but i only have a garmin geko. works great at only one place i run and thats where i go when i am concerned about how fast it really is. lol.
i think you are gonna break sixty pal. if you have to run in a river with the current. should get you the few mph you need. lol.
izzy

[JMSCARD]

Just goes to show how much I have to learn... I would have thought 4s with the 1515 1y would be fine? No wonder I spend so much money on esc's ... Lol... I popped a cap on my hydra 120 in my drifer last weekend and smoked a himodel 200 in my df 33 with a 1521.... I have alot to learn!!

[Joe M]

Have a buddy runs a ul1 15151y 240 hydra and a m445 prop and has no problem joe m

[D&D]

Hey, that river idea sounds good to me. I can to to the Tippecanoe river just outside of town and maybe I can get my 60mph. That still counts as 60, right? Now if only I can remember to run down stream and not up stream.....

[D&D]

I have now run the Y537-3 two times. The first time the boat did not handle well at all, terrible trim with that prop and it crashed. Second time the water was too rough, but minor changes to the strut and moving more weight (batteries) back over the prop settled the trim down - but again the water was too rough. For a setup like this the water must be like glass and the wind at "0" - still waiting.......

[D&D]

OK, back in NC on home water - no excuses, water much like glass and no wind.

Ran the D&D MM this morning with the strut flat with the bottom of the boat using a Y537-3 prop - Again, stuck at 57.5mph. Just can't seem to get away from that 57mph. The boat's attitude and ride was not an everyday run prop or setting. However, I will try raising the strut some and see how it will work with this prop.

I then ran the D&D with a new X440-4 (I had modified the old 440) and the boat looked lightening fast. However, that turned out to be due to the almost perfect attitude and ride of the boat. It actually ran 55.5mph. I would call it a great running sport MM and that is what I built this to be, but......

My wife shot some video (her first attempt) on my new Cannon Power Shot still camera which will take 720P video and I will see if I can figure out how to get those to YouTube. However, the camera has some short comings, like you can set the zoom prior to starting your video but not during the video. I could not seem to get a good shot of the GPS device, difficult to read the screen. Lastly, my running site is at the end of the lake so it is difficult to get a shot of the boat running by and it I go out to far then I am running by the dam and I want to be careful there!

I don't want to complain because the boat is a great running MM, but I just know that 60MPH is in there somewhere. It's just hiding from me right now!