party_wagon

My goal is to build a 2s lipo mono that will go 40 m.p.h. and operate off of a 2s lipo.

As far as hulls are concerned I believe I will find around a 25" hull to work with. I would like some advice on a good stable hull for this aplication.

From my research a neu 1509 .5d will deliver the most power out of any motor on a 2s lithium pack, around 900 watts of power. Since the motor will rev at close to 60k rpm which is way to much I plan on using a planetary neu gear box that will bring the prop speed down to around 16000 rpm. Now, I will have around 900 watts of power being delivered at 16,000 rpm which means I can run a tremendous prop on this little boat.

CadillacDTS2001

ok i think if you want to go that fast you need a couple things. . . well rather can do with out
you can do with out a planetary gear box and a 1509.
to do 40+mph you will need a 1512 or 1515 without a gear drive ( stupid idea) some lipo batteries with a good 25-30C discharge. and 2P them for sure.
25 inch hull? well MAYBE but i would suggest you find a 27 inch hull or something like that
Lipos. Here is what i recommend
http://www.rclipos.com/PolyRC30C.htm
go to the bottom where it says 4500's and 2s. . . they are 124 dollars and you will need two.
You will also require a charger and balancing harness to charge them.

and a hydra 240 is allwayse a safe bet.

ctonez

yup, that oughta do it[sm=thumbs_up.gif]

party_wagon

The 1509 will put out a whole lot more power then the 1512 or 1515 w/ a 2s lipo so why should I run one of those instead?

CadillacDTS2001

more power ? HA how do you figure.
please tell me

party_wagon

Well, a 1509 will put out around 900 watts of power @60k rpm. & a lipo will push the 1509 .5d to right around 60k rpm, 900 watts of power. The 1512 puts out around 1000 watts of power @60k rpm and hits around 40k rpm and the 1515 is even worse. It will have a huge current draw, but it is more powerful. These larger motors were designed to perform well with more voltage. The reason people use the 1515s is because the amp draw is lower w/ the same amount of power so you can use crappy batteries. A 8k mah 20c pack w/ a decent esc can deliver this power with out too much stress on the componants.

CadillacDTS2001

what you said contradicts your self.
you said
which would mean you are drawing about 70 amps
but then you say
which you JUST said is not the case.

Yes most smaller motors do pull more amps but amps don't get you crazy speed. good choice on motor do. .
sorry man if you want to go fast listen to me and run a 1512 or 1515.
a 1509 will work but maybe on 1P and in a tiny hull

fact: a seducer running 1515 1Y on 2s2p lipo runs 51 mph.
you will not get a 1509 with a planetary gear box to do that.

alloutcustom

ok, ive never understood how neu motors worked size wise. what is 1509, 1512, 1515. just want to know for later builds.

Thanks

ctonez

Actually, a 1509 will work in a 25-27 inch hull...I ran a 1509 1.5D in N2 last year...I'd say it was running mid 40's at least. but still needed 10,000mah to be safe for 5-7 laps. That was in a CF El Lobo though...but I plan to run that in a No Step 2 for N2 next year, the El Lobo was way too small for the power. I had to run the smallest props in my box though...430, 432, and 632. ESC was a Cuda125. Same setup burned Cuda80's.

Quicksilver1

all these numbers make me feel like I'm back in calculus. Like reading a different language....

party_wagon

The 1512 will only reach about 66% of it's potential power of around 1000 watts, the 1509 will reach around 100% of its 900 watts. 900 is more power then 660 any day of the week. However, I really don't need a large boat for where I'm going to be playing around and from what you just told me a 660 watt boat will hit 50 m.p.h. in a 33 inch hull so I would be way over powering the boat for what I need. What do you believe would be a good rough water hull that can hit 40 m.p.h. and how much power would it need to hit 40 m.p.h. From the sound of things I may just run a traxxas vileon system, it puts out around 450 watts of power on a 2s lipo. and will rev at around 24k rpm. I really don't need a boat that will go 60 m.p.h.

ryan_t888

If the 1512 has a potential of around 1000 watts, who is limiting this to 66%? Wattage is the product of current and voltage. If voltage is constant, up the current. (BTW, where do you get a max of 1000watts from?)
As power increases, more excess heat is given off. Larger motors can produce more power and handle the heat due to more volumetric mass. With the increase in volumetric mass, the motor can transfer and get rid of more heat.

If Kv is somewhat close and final prop RPM is close it would not make any sense that a smaller motor would produce more power than a larger motor.

Just as I do not like to run too small of a prop on a given hull, I also don't like to run too large of a prop on a given hull. 900 watts @ 16 000 RPM is going to be to large of a prop for an N2 IMO.

Ryan

CadillacDTS2001

yeah 1.5D sounds like a great motor.
. . but this guys says .5D custom wind. . hmm ok

party_wagon

The 1509 can reach its maximum potential on a 2s lipo and the 1512 can not reach its maximum potential. The 1512 can only reach 66% of its maximum potential on a 2s lipo. Simply put, the 1509 .5d puts out more power per volt, but the 1509 can only use a 2s lipo effectively. Since the 1512 can effectively use a 4s lipo it can reach a greater total power, but you will have to suply it with more then 7.4 volts to reach a greater power. Now, like I said a second ago 900 watts of power seems like it is way too much. Could some one suggest a good hull that will stay stable in rough water and hit 40 mph w/ the right conditions. Then let me know how much power I would need to push it to 40 m.p.h. If you don't know terms in watts then recommend a motor config and i'll see if I can figure out how much power I would need.

ctonez

You're right Taylor...I forgot he was talking about .5D - seems a little unnecessarily hot.
PW - I'm not sure all your math is right...I think your calculations work out, but there are too many other variables to consider. Prop size/pitch being one - loaded RPM vs. unloaded - temps - torque - actual voltage output,
A hot wind in a motor isn't always what determines speed. Torque, weight, prop, water conditions are also important things to consider. What it comes down to at this point is - why would you spend $270+ on a motor for this application, when an Ammo or Fiegao would get you to 40+ no problem? You'll need a Cuda125 or better for this application if you're gonna use a Neu too, that's another expensive piece of equipment.

Taylor's right, you'll need 2 packs, and at that point you could go from N to P and get an SV system...get you to 40 in no time. or get an Ammo and a SV ESC and go 45 in no time...maybe even 50.

I think trying to maximize the wattage (potential?) is the wrong way to think about this...I also agree that you should scrap the gearbox idea, but it sounds like it may be your thing...If you already have the motor, and are trying to find a way to use it, then I understand, however, if you haven't purchased it yet, I'd consider another alternative.

What setups are you running currently?

party_wagon

I haven't invested anything in to the boat yet. From what I have seen though 900 watts of power is way too much for the boat though so I now just trying to get a feal for how much power I need to power the hull and what would make a good hull for these aplications.

Peace_mit

Stock sv27 ,lipo 2s2p,oc x440/3 ,pull about 900 watts at 45mph ?

Stock sv27 ,IB4200,oc x440/3 ,pull about 500 watts at 39mph ?

but the motor is rated at around 500 watts .

CadillacDTS2001

there is more to rc boats then SV27. . .

ctonez

huh?[sm=71_71.gif] where did those numbers come from?

Peace_mit

the data come from oracle data recorder + gps.

ctonez

Isn't that 4s2p though, maybe I'm confused? party wagon is talking about 900watts with 7.4V, but would have to run 2packs in parallel to get the necessary capacity/balance...which is why I thought he may as well go 14.8V...but that's not what he's after, even though that'd probably be a cheaper way to get to 40+ IMO.
It is interesting though, how much difference there is between the lipos and the Nimh's as far as those wattage numbers[sm=eek.gif].

party_wagon

I could purchase 30c 5k mah packs and easily run w/out problems. However I don't need that much power. Now, what would be a good cheap hull that can hit 40 m.p.h. and handle choppy waters and how much power would I need?

MarkF

Your going to have to run a lot more amps in the 1509 than you would with the 1512. I just had a straitline event this past weekend and I ran a 1512 1D in my shovel on 2s 2p and got to 61 mph with a v940 prop. If you put this in a mono then you could easily get to 40 with a smaller prop and not so many amps. Your set up will be more eficient and you wont kill your speed controll so easily. Also I would look at the delta force 27" hull if you want a good mono.

Mark

Avanti27offshore

I don't know that you could keep a 25" mono in the water and controlable at 40+ as you will run out of running surface.

I am a v-bottom fan but I think a cat or hydro would reach your goal with more stability.

party_wagon

I think i'm just going to run a el lobo 22" inch fiber hull. It is more then capable of 60+ m.p.h..