Motor for scale 60" apache? -nothing too fast

[FastVee]

First: I know this size hull needs huge sized low kv motor, many cells and expensive esc to get it going fast.

HOWEVER...

I want to build something BIG that is scale looking and going ,like 15mph ,if it planes and moves like the real thing on plane I´m happy.

-like this that I build with my friend http://www.youtube.com/watch?v=oFNFu5OfjVU
the speed on that is good enough for this project.(that is way bigger boat then the apache I´m getting) -it has dual 820´s

I am still thinking what (52", 56" or 60" ) hull I will choose, but the 56-60 looks like the ones for me to choose from. (check my other thread on that http://forums.offshoreelectrics.com/...ad.php?t=20728 )


Thinking of that LEOPARD 5692 and 4-8S (Cause I have few 4 and 3s lipos, and my charger goes only up to 5s). -4s would be great, then there is no need for new ones and I am on budget here.

The esc I´m thinking about is Himodel 4-8 200A (again, the tight budget)

I will use the MHZ Z-drive(it is geared +16%)

I have Graupner 820bb brushed that I can put in this thing with MMM esc and I know it will move fast enough(even on just 4S like on that video) , but if I want brushless, is this leo 1000 or 1300kv ok or something else you would suggest I look at?

-Pate

[forescott]

I would run the leopard 5692(1090) on your 4s packs in parallel with something like a 60mm prop. F.E. calc. puts speed right around 30mph. You will need to swing a pretty big prop to get that hull on plane, and a motor kv/battery voltage combo that will get you your desired speed a wide open throttle. If you run around at half throttle to achieve 25mph, the esc will heat up and most likely fail. Your 4s packs are going to need to have a pretty high mah and c-rating as well to ensure the motor is getting enough juice.

[FastVee]

Thanks forescott, I dont mind if the boat goes faster then 15mph, that is just the speed I will be happy to get. If it goes 30 , that´s great!

4S packs are not that expensive, if my 30C 5000mAh is too little I´ll get new one(s).

1090kv on 4s and that 16% gearing would give 18700rpm so that is about the same as on gas engines and should do well.

Any ideas of what Amps it will draw? -the motor specs state:

Model: LBP5692/2Y
Max Amps: 160A
Lipo Cell: 5-9s
Max Power: 5500W
KV(RPM/Volt): 1090KV
Resistance: 0.0060
No-load Current（15V） : 3.1A
Diameter×Length (mm): Φ55.8×92
Mounting hole depth: 8mm
Length of extend Shaft : 20mm
Shaft Diameter (mm): Φ6.0
Weight: 880g


so 160A max, but the true A could be somethind else....

-Thinking would my Mamba Monster Max do the job, or the himodel...

(I do have the 2200kv monster motor, but that must be way too small??? )


-Pate

[Jeff Wohlt]

A big outrunner could be cheaper, turn a bigger prop and pull less amps on the ESC

[forescott]

I forgot about the gearing. Still would put less stress on the esc. and could swing an even bigger prop. A 1/4" flex shaft would be a "must", and your 5000mah 30c packs should be fine. I'm not sure the price of the esc your thinking of but I like the turnigy/seaking 180 with the leopard motor. Its about 80-bucks @ Hobbyking.

[forescott]

I would think the amp draw would be low. The 2200 is definetly too small to spin a prop in the 60mm range. You need the big diameter can with low kv/high torque. A water cooled esc would be better in a sealed hull and even though the monster is a good esc it's pretty small and I can't see it holding up well. I'm curious about Jeffs comment about the outrunner. Little screamers used to make a 63mm outrunner that was a replacement for gas boat engines but the kv was pretty low and I think they have been discontinued.

[Flying Scotsman]

You may wish to check these old fashioned brushed motors and transmissions out, they are very durable. Check through the pages 1-4

http://www.mackproductsrc.com/mack_power.htm

Douggie

[FastVee]

Jeff, if you got a motor in mind, please link it . -I know nothing about outrunners.

forescott, the himodel esc is 4-8s 200A and it cost about 50$


Douggie, thanks for that link.

The largest motor I found there is this 7720 Marauder Race Motor


Length: 3-3/8" Width: 2-1/4" Height: 2-1/4"
Shaft is 5 mm in dia. x 9/16" long
Weight: 18 oz.

It looks a lot like the 820bb that I have. (I only understand metric, so idk 4 sure about the measurements)


Nominal voltage 20V
Operating voltage range 16-24V
No-load speed 24000 RPM
No-load current drain 2.5 A
Current drain at max. efficiency 21.3 A
Stall current 166 A
Max. efficiency excl. gearbox 82%
Permissible rot. direction R and L
Case lenght, excl. shaft 68mm
Diameter 48mm
Free shaft length 13mm
Shaft diameter 5mm
Weight 450g


-Pate

[Jeff Wohlt]

Well this one would even be better than the Brushed. Run it on 6S and a 450+ prop. More efficient. No brushes to deal with.

http://www.hobbyking.com/hobbyking/s...dProduct=11980

I just think you will get more performance and less struggle.

Keep the CG back

[Jeff Wohlt]

Here is one running on 6S with a 43" mono. Yes yours is bigger but keep the CG way back to keep it running clean...keep that front out of the water.

http://www.youtube.com/watch?v=0ABBsk8ia-4

[FastVee]

Jeff, that looks like a quite small motor? -and~450 prop? -can it even push the boat to plane?(and wouldn´t it look quite small on about 60" hull?)


on 4s that´s 24000rpm´s and on 6 that´s 36000rpm´s ,that sounds a bit high?(the outdrive is geared to +16%)

I get that on 6s the A draw is smaller then on 4s , but I cant get a new charger atm(just got new LRP charger and it is 5A 5s max) and I was hoping that I could use one pack in the boat so charging would not take a whole day.

the motor is rated 5-8s so 4s might not work...

That is cheap price thought, so I could try it...

Do the outrunners require a water cooling? -I cant see how a water jacket would work so old scool style coil?




I am just throwing ideas here, but If the motor is that cheap and if I get something a bit less scale for the drives(z-drive out, strut in) I could even get twin motors...
Thinking....


But I guess that the scale z-drive and one motor must be enough, just need to think what to get...

Please throw few ideas at me, if you got em.


-Pate

[Jeff Wohlt]

Forgot about you using a z drive

[FastVee]

Why no no to the Z?

Any scale strut/rudders out there? -I only found this and idk how it will work (alot of flex showing) http://www.wd200-modellbau.de/?Antri...FDirektantrieb

and these

http://www.wd200-modellbau.de/?Antriebe%2FDrives:Lenkbarer_Antrieb

http://www.wd200-modellbau.de/?Antriebe%2FDrives:Lenkstrut

This looks kinda kool also http://www.wd200-modellbau.de/?Antri...er-Strut_Kombi -I dont get how this works. square flex or what drives that shaft...

And this( needs a rudder thought) http://www.wd200-modellbau.de/?Antri...cale-Strut_123

[Brushless55]

Here is one running on 6S with a 43" mono. Yes yours is bigger but keep the CG way back to keep it running clean...keep that front out of the water.

http://www.youtube.com/watch?v=0ABBsk8ia-4

that's actually a 39" mono

[FastVee]

Just placed an order of a 58" apache.

http://www.waveridermouldings.zoomshare.com/0.html

Will be 2 layers of glass and one carbon layer =strong

Still asking motor suggestions!