Motor for scale 60" apache? -nothing too fast

[Flying Scotsman]

I would still go with a transmission and a big prop for what you want to achieve. My humble 2 cents

Douggie

[Jeff Wohlt]

A gear drive would be a good idea for that big of hull. Or a turbine :)

[FastVee]

Douggie,I will think about brushed/gb, but direct driven brushless would be so much easier(and expensive... )

I plan on using single motor(for now) , and the outrunner that Jeff pointed sounds ok, but I dont know how big prop will turn with that.
Kv (rpm/v) 1400
Weight (g) 349
Max Current (A) 110
Resistance (mh) 7
Max Voltage (V) 30
Power(W) 3250
Shaft A (mm) 6
Length B (mm) 57
Diameter C (mm) 49
Can Length D (mm) 33
Total Length E (mm) 78

The Leopard 1340kv is possible(in budget) and easy to water cool. But the same thing is wrong with this : -no idea of prop size.

Model: LBP5692/3D
Max Amps: 110A
Lipo Cell: 4-8s
Max Power: 5500W
KV(RPM/Volt): 1340KV
Resistance: 0.0046
No-load Current（15V） : 4.1A
Diameter×Length (mm): Φ55.8×92
Mounting hole depth: 8mm
Length of extend Shaft : 20mm
Shaft Diameter (mm): Φ6.0
Weight: 880g


I just checked and my charger does go up to 6S so the 6S is option.(and I have 2 40c 5000mah 3s packs to try) 6s packs are not that expensive on hc so 2 of them in paraller is an option also.


With this power I guess the Z-drive is no longer an option.


Jeff, if you give me a turbine or two, I will install´em




-Pate

[befu]

They also make that outrunner in a 1100kv version. That would give you more torque to spin the prop. The thing to remember is what speed are you looking to run?

I defied the odds and ran a 40" scarab on a 3648-1450 turnigy outrunner. Most of us thought it wouldn't break plane or just burn up, let alone run. the water got hard before I really tuned it in, but it hit 33mph on that motor no problem pushing a 42 to 47mm prop.

It actually made plane and into the mid teens for speed on a 47mm prop and one 3s-2200-20c battery. yeah, a $8 battery from HK pushed it onto plane in a 40" big vee hull.

If you are looking for mid 20's to mid 30's, I think two of those 3648's would do it on the 58" hull for the slower scale speed. Two of the 4030's would really wake it up!

Try some of the lower power setups and see what happens. The outrunners will really spin a big prop and do not need water cooling, or a cooled mounting plate works well. Remember, most of the experience on this site is for racing boats (hence the FE), when you slow these boats down it really changes what you can do with them. Doubling a boats speed requires at least 4x as much power, so taking a large hull like this from mid 50's down to mid 20's will drop the power need down to 20% to 30%.

Those two builds you mentioned made me try something out of the box, and it worked. Build on that and see what happens. What does your princess weigh in at and what does it have in it?

Good luck, try something new. Remember, most here have a lot of great knowledge when it comes to going fast. The slower more scale builds seems like something newer here.

Brian

P.S. ScarabChris has a build here with a large mono like this. his is high power and he thinks it will go mid 60's. So if you want half that speed, look at something with 25% of the power. Also look at the speed estimator in the tips section on OSE, very handy for estimating speed based on KV, cells and prop.

[JMSCARD]

my vote leopard 5692 1090v on 4s and/or 5s (since you already have some) with a Turnigy 180 esc and maybe start with a x452/3 or x455/3 prop.... should get it up on plane and the speed you desire.. just a guess.... tough thinking this way instead of thinking for all out speed...

[Punisher 67]

Does it have to be 4s , that is a large boat for only 4 cells .

[FastVee]

Brian, your´e right ! -the princess weights about the same as the scarab/ apache(thinking witch version) and it only has 2s 1600kv system...

This has to go faster though , cant give exact speed I want until it moves -I know keeping it scale, but that hull deserves some speed, maybe 30+ mph.

Peter, 4s is not a must, I can go to 6s. Just hoping I can use the 4s if I want to go slower.


The 5500W that leopard "promises" would def. move er


I really think that KISS method would work here also, so 1 motor and esc on 1 strut must do... -dual outrunners is still doable-what is the timing on these, can they even work as a counter rotating pair?, but if the power is too little I cant afford dual leos until summer 2012......



The z-drive starts to sound too expensive now...need to look other options that are semi scale...


-Pate

[Punisher 67]

Just looking at the potential amp draw on 4s , thought 8s might be better option but with half the kv................just a suggestion

Also on that large a hull 30+ mph is going to push your equipment pretty hard on 4s , 6s should net you some good results

Love the progect though..........................

[FastVee]

Peter, so you think that 1340kv (29700rpm) on 6s would work or 1090kv(24.000rpm) on 6s? -I guess the prop could be bigger on 1090?

-the gassers have about 18.000 i belive? -so idk.

The reason I´m limited to 6s(prefer 4s) is my charger(charges to 4s 1C, 6s way less then 1c),the lack of cheap 8s esc´s(doubt the himodel 4-8s 200a can take 8s) ,and my budget.


-Pate

[Punisher 67]

NO NO not the high and its going to depend on motor , I can with a 750kv Neu 2230 and 5cells get a 25LB boat to about 50km / 30mph with a 2616 ABC prop which would put it at about 15,000 rpm . but this is going to depend on what direction you go with motor . I ran the boat on 5 & 6 cells just to see how it would work , the boat normally did 60mph on two banks of 10cells

I think 6cells with a 750kv 5692 Leoperd would get you either at or close to your goal without pushing the batteries or your ESC . This is just my opinion there maybe others that could suggest better combinations but with high weight and low cells you are going to have to find a happy medium between KV / Cells used

[FastVee]

Ah, ok so smaller rpm´s and larger prop is the correct way?

The hull is 5kg empty.

So 730kv leopard 5692 ,5-6s would be close to the truth?
13000 rpm on 5 and 16000 on 6s. and something like this http://cgi.ebay.com/6717-3-alu-prope...item1e5d01d7d8

I guess that low kv motor would give quite long driving time?

Still thinking my choises, outrunners are cheap and 2 is option(if they can counter rotate) , and that leopard is about as powerful what 2 outrunners output, so idk

[FastVee]

Ok, I have ordered 2x 200A 3-7S esc´s, so this will be twin.

Will use 6S/motor

That limits my motor choises to turnigy outrunners.


I guess that single 880kv on 6s would be ok, but if I get 2 motors can I get higher kv motors?

If I use 2 motors, is the 1100kv ok, 1400kv too much or is the 880kv the ticket to get this going!



880KV http://www.hobbycity.com/hobbyking/s...dProduct=11143
1100KV http://www.hobbycity.com/hobbyking/s...dProduct=11102
1400KV http://www.hobbycity.com/hobbyking/s...dProduct=11980

So help me out here, what do I choose!

-Pate

[Punisher 67]

I personally would not go 1400kv , even at 880kv on 6 cells your rpm would be around 17,500 . this combo would probably give you the longest run time and easily give you your 30+mph

[FastVee]

Thanks Peter, I was just paying my order of two 880kv motors

Now I need to think what propellers to get...

-Pate

[blackcat26]

What about x457's? They are made in both rotations......Someone with big boat experience chime in here.