I'm a newbie to the elec. scene and am genuinly curious about brushless motors, how they work, power input/output and the biggest anyone makes. I'm researching a fulll scale project and wan't to go fast.Any thoughts,info,or opinions would be great.

What's full scale? 1:1? Going to build an 18 footer?. There is some good info in the thread running about the super hawaii right now. 55 or 60 inch boat with the biggest e motor I've seen. Very big money involved. More than I paid for my first ski boat.[&:]

Sorry I meant the Dumas 55 scarab. Read that thread on the first page.

O.K> so your on to me.If i scale up some crazy pletenburg motor to have power output of @900 hp.I would need a 500hp gas turbine spinning a generator somethin fierce right?Has anyone done some number research on it?Set aside cost.Any brshless generators out there?Am i barking at the wrong tree?

yes

Ive looked at a lot of electric powered systems from hobby grade, to retrofitting an ole CBR track bike( its feasible in that respect but only for a drag race not 15 mins on a track!), to one of those three wheeled full electric cars. But for a boat? Not feasible in my opinion. Think of the power output needed on those giant cats they run in europe, now by giant Im talking 70" there Lipos are longer than my whole arm an are in the ranges of 4-5k a piece! Youd need all you available weight on whatever fullsized hull you have just to carry enough power for a few minutes of run time. If you were to put a Gas powered motor to generate that power for a electric motor then its redundant. Just buy more cubes for your boat. Youll be hapier.

-Wayne

if you want alot of RPM. get a renisis Rotary engine for the boat, They are used on Jet boats and some smaller boats as well. . . 12000 rpm eazy

Maybe just an idea but the smaller the cheaper. Unless money is no object then just get a jet motor from some airplane either f-18 or something newer then stick it to a boat and there ya go.... just kidding though. But seriously you can get some high speeds out of the smaller boats, somebody hit 50mph in a 26in black jack or 130mph+ in some rigger. Somebody would have to chime in because I'm not willing to look up.[X(]

Ivan.

I was thinking more along the lines of on-board/on-demand power generation with the turbine.Can a brushless be used as a generator?Would there be a substantial loss from gen to motors?Am i really dreaming when i think about a 450hp. brushless motor turning 18,000rpm?Turbines are great the transmissions are not.Can brushless motors run in reverse?

just some info a brushless motor runs off of AC current. heck just put a fuel cell in it . i was reading about one that put out around 300w at i thank 36v not sure on that cant find the specs like i did last time . for like 3k and its like 4x8"

C cat. you are dreaming for a 450 Hp Bl motor.
If it was possible i would suspect about a 300K price tag.

Use a gas motor. Don't beat around the bush. K.I.S.S

here is the specs http://www.horizonfuelcell.com/file/H-Series.pdf

for $ go to horizonfuelcell.com

OK the bottom line is Iwas thinking a 400-500 hp turbine turning an efficient brushless generator would be an easier way to have a single engine twinn drive full size powerboat.I quess it would be feasable to scale up a brushless motor and have at it but with money and time invested it might be cheaper to go tripple turbine.It's only a 32ft.cat anyway,just thught it would be cool to be the first high-perf.full scale elec. guy.Thanks for your time fellas.

ok you basicly wont a trane drive system . i did find 400hp brushless motors but man your talking about some money

who makes,em? do they turn sinister rpm?how much?

no man your thanking wrong the bigger some is the slower it has to turn . most large motors around the 5 hp range only turn 3500 rpm . theres one i just found its rated at 384 hp and 2982 lb ft tq with an Amp draw at 425A rms and i thank it onlu turns at 1750 rpm check this place out if i find more ill edit with more links http://www.powertecmotors.com/pactorq.html

Couldn't I scale up an existing brushless motor?Then dump the power to it?Need better rpm,s near 4500 at the prop.

you could always gear it up with almost 3k worth of tq .

C cat. why do you want to.
to get a 400 h/p b/l motor you would probably see a diameter of 9 feet and weigh over 7 tons


just use a gas motor. K.I.S.S man this thread makes me laugh big time !~!

im with taylor. i would just put a gas in it but i dont have the money to just blow on something like this . its a neet idea but lots of $$$$$ . and taylor that 384 hp bl i found is only 16 " diameter

i was joking.

Thanks for your insight.

For the price of batteries that you would need to move something with this mass at the speed you are looking for brushless electric really isn't quite yet feasible. You'll be much better off with a gasoline engine for this application. I'm not saying it can't be done, but it won't be cost effective with the current battery pricepoints and technology.

I was planning on generating power from a turbine (fuel) and using it to power the two giant brless motors.Possible need for batts. at idle, definatly for startup.Seems brless motors would make alot more torq on the low end,and definatly easier to counter rotate.Just don,t like the idea of a tranny behind a turbine,or the cost of TWO turbines.I need 4500 rpm to be a go fast guy though.

I still just don't understand why? You want to put a turbine and huge BL motors in so you can reverse one more easily. Mercury machine has been running V8's backwards for years. It's done. You pose an intresting project but all said and done you can go alot faster for less a few different ways. That's why nobody has done what you are proposing.