You were making an assumption of a "problem" based on my estimate of speed to another person...............you said something was wrong if its 30ish.............geez, i was replying to OSU's question and you jumped in with your "somethings wrong" comment, i didnt pm you to tell you the speed out of the blue......once again, based on an off the cuff guess of speed for the guy. And yes, now im saying between 25-50 to be certain my estimate is correct for you to critique me with. I'm not "certain of 30ish" but im certain of my range, which includes 25,26,27,28 etc. pick one. And i do run low kv motors with high volts as im sure you have read...so i guess i have "winning combos that last" also. Why would you volunteer the speeds of your boats, no one asked...........do you think i care any more than you? Got any vids of your Fast boats?

I don't really have a set speed i want just want to see what the multiple motors will do and it will be fun to make the gearbox i am thinking of in my head to connect all the motors, the setup will change a lot just like all my boats.

And the 3000kv KD36 works pretty well on 18nihm cells and it is pretty close to 6s with a 54mm prop (geared down a little) so i think 6s would be work at least. I had that in my villain before the KB45 <u>without any water cooling</u>. That is what got me started on that brand because they can handle A LOT. But that is a lot of unloaded rpms...

Another idea is two KB45 1200kv XLs on 9 s each and because i have one and an esc that will work and just get another motor and esc.
That would be 6660 watts too at 100 amps... and two motors are prolly gonna be faster than three at the same power and less rpms.

I'm with ya man, but you really don't want that much rpm in a boat..
3000kv on 6s is over 66,000rpm! you wll smoke your motors in a boat the size you want..
and the KB45 1200 kv motors on 9s is 40,000rpm, those motors will generate alot of heat and burn up with those rpms.. The big KB motors do not like much rpm above 30,000 and to put that in a boat is more amp load on them..
and the 3300 watts per motor listed, is the peak of those motors that they will not get to because they are so inefficient, they will burn up
Steve at OSE stopped selling them because they are such bad motors
go with the new 580 motors
Like one of these.. http://www.offshoreelectrics.com/pro...-580-L&cat=116
multiple motors would be awesome, I'v thought about the same thing running twin KB45 1200kv on 6s in a Blackjack 55.
I've found the gearbox for it but I've lost interest in it because those motors are amp hogs and I would rather run one Neu motor on 8s and get more speed with more runtimes
keep in mind to running multiple motors you need alot of batteries, so my twin BJ55 would need twin 6s 5000mah packs or bigger and my runtimes would only be about 5min
but what ever you do find a motor combo that gets about 25-28,000rpm tops
anything more than that could spell smoke for the motors or escs

Quote:

ORIGINAL: rebuilder

Quote:

What? Now your saying 25-50mph????
Ohh boy, I realy don't care how fast your boat is...
All my boats run low 40s to mid 60s and all verified by gps
all low kv motors and good volts = winning combos that last

You were making an assumption of a ''problem'' based on my estimate of speed to another person...............you said something was wrong if its 30ish.............geez, i was replying to OSU's question and you jumped in with your ''somethings wrong'' comment, i didnt pm you to tell you the speed out of the blue......once again, based on an off the cuff guess of speed for the guy. And yes, now im saying between 25-50 to be certain my estimate is correct for you to critique me with. I'm not ''certain of 30ish'' but im certain of my range, which includes 25,26,27,28 etc. pick one. And i do run low kv motors with high volts as im sure you have read...so i guess i have ''winning combos that last'' also. Why would you volunteer the speeds of your boats, no one asked...........do you think i care any more than you? Got any vids of your Fast boats?
[/quote]

oh man, IMO your set up makes no sence
big boat with KB45 motor spinning 35,000rpm with a 45mm prop?
should be going 50s +, and if its only getting 30mph something is wrong with that kind of rpm
your guess of 25-50mph is a huge difference that cannot be taken serious IMO
high kv with lots of volts makes for smoke in boats this size with amp hog motors
and 30mph is not a winning combo, boats that size need to run 50+ to win on race day lap after lap
I have a 29" race boat that does right at 60mph with a 45mm prop, running a 2300kv motor on 4s (34,000rpm)
my UL-1 does 52mph on a 43mm prop running the 2030kv motor on 4s (30,000rpm)

it seems to me people need to go back to the drawing board

if you have 3 motors, is'nt the centre prop going to cause drag ?
will you have the centre prop moving at start up with the other 2
OR
will the centre motor kick in when you reach top speed (like nitrous oxide boost) 
wont the centre prop cause prop walk with the left prop aswell

they make gear boxes that the motos work together as one big motor...
but you need escs and lots of batteries to make it work, and hope the motors are in perfect kv

or you can do twin drives with twin motors

I am gonna stick with the KB45 i think because they are less expensive. And yea i would make a gearbox, not 3 outdrives. Allthough i have seen it done! Even on pontoon boats.
If i did have three outdrives they would all spin a prop at about the same speed the entire time the boat was moving.

I would run the KB45s on 6s most of the time, I am gonna see how one does in my villain first.

well, if you use 3 motors, the middle prop has to be forward or behind the outer props

personally, i would stick to single drive but in your boat go with 2

Oh and it would deff be a sub surface drive so there would be no prop walk.

fair enough, are you using brushed or brushless

brushed are easy to use in series but brushless are a bit difficult to wire in series

I wouldn't put brushed in a 47inch boat.
The KB45 and KD36 are both brushless....
They arn't hard to wire at all. I think you are thinking if i had one esc.. I will have one of each motor.

ok, my apologies

1) great, I think the KB45 motors are good if you have the right volts and setup, otherwise they will pull massive amps..
2) I'm not sure what you ment about the three drives spinning the same all the time??
two outdrives would be work...
3) a KB45 motor on 6s will run much much different in your Villian than in your 47" boat! one cannot compare the performance between the two acurately...

4) what speeds are you after??
this is the most important question for you.. the setup for a 35mph boat is different than a 40mph and again the setup is much much different for a 50mph boat
how fast do you want to go with this boat?

we are behind ya!

Thanks!
The villain is to see how much of a load i can put on it on 6s to keep it under 100 amps.
And i guess the speed i want is as much as i can with dual KB45s. I am thinking a subsurface drive with a 3/16 or 1/4inch flex shaft to a 3/16 or 1/4inch shaft and i could gear the motors down a bit from the gearbox to use 1/4inch stuff. (i have a lot of 1/4 shafts)



The three outdrive thing was for nick. Just wanted to to say all the motors would be on the entire time if there were 3 outdrives.

ya, let us know how the Villian runs with that beast!
that boat is light and will fly
now you got me thinking of my 55" cat again...

Yea! the bad part about the villain tho is it doesn't have barely any steps on the hull so it in almost like a displacement hull like a pontoon. i have been thinkin about how i could add some.

I wish i could mod the shaft on the motor so i could put two inline!

i was asking about the three prop setup because some people have all start upbut some have it start up near full throttle, apologies if i seemed out of line or rude

nope! not at all! Ur fine

And i have a lot of lower units from old k&amp;b outboards so dual electic outboards might be and option too!

its just dawned on me, with 3 outboards there would be no drag, i was thinking of the wrong thing, surely B/L would work on your old outboard lower units, could'nt you make a plate adapter to allow you to mount B/L motors

i know the graupner units come with an adapter for a smaller motor </p>

I sure can! And i would only have to buy the props for the entire outdrive rudder and hardware!