Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Brushless motor advice needed...  (Read 2365 times)

U-33

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,338
  • K-157 Vepr. Akula-11
  • Location: Eastbourne, Sussex, UK
Brushless motor advice needed...
« on: December 06, 2013, 05:51:30 PM »

Could someone point me in the right direction for a brushless motor suitable for a Trumpeter Kilo, please? My last one had a 380 motor in it, but this time around I want to go brushless to save internal space in the WTC.

Thanks,


Rich
Logged
Rich

K-157 Vepr. Akula-II (project 971U)
---------------------------------------------------------------

~~~~~~~  "Motorflotes need love too...."  ~~~~~~~

MotorFlote build log : http://www.modelboatmayhem.co.uk/forum/index.php/topic,15222.0.html

nick_75au

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 257
  • Location: Brisbane, Australia
    • Logan City Marine Modellers
Re: Brushless motor advice needed...
« Reply #1 on: December 07, 2013, 01:27:12 AM »

What size prop and what RPM would you need? or which 380 would you use normally, specs??


Wild Guess until then but a 22 mm outrunner would have equivalent to better power than a 380


http://www.hobbyking.com/hobbyking/store/__5384__C2226_Micro_brushless_Outrunner_1800kv_21g_.html



Nick
Logged

tsenecal

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 331
  • Location: Arvada, Colorado, USA
Re: Brushless motor advice needed...
« Reply #2 on: December 08, 2013, 03:24:27 AM »


the trumpeter kilo is a smaller, 20" long "pool" sub...


you will want something a little milder.  something more like this:


http://www.hobbyking.com/hobbyking/store/__19611__NTM_Prop_Drive_28_36_750KV_265W.html




or slow down the one nick pointed to above:


http://www.hobbyking.com/hobbyking/store/__6568__Power_system_w_gearbox_EPS100.html
Logged

U-33

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,338
  • K-157 Vepr. Akula-11
  • Location: Eastbourne, Sussex, UK
Re: Brushless motor advice needed...
« Reply #3 on: December 08, 2013, 08:20:57 AM »

Thanks for the assistance fellas, much appreciated.   :-))








Rich
Logged
Rich

K-157 Vepr. Akula-II (project 971U)
---------------------------------------------------------------

~~~~~~~  "Motorflotes need love too...."  ~~~~~~~

MotorFlote build log : http://www.modelboatmayhem.co.uk/forum/index.php/topic,15222.0.html

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,910
  • Location: North London
    • Dive-in to Model submarines
Re: Brushless motor advice needed...
« Reply #4 on: December 08, 2013, 11:20:20 AM »

The problem with fitting brushless into subs is that most of the motors on the market are aimed at aeroplanes not marine use, and they tend to be wound for higher RPM, especially once you start looking at smaller motors.

That's not a problem if you are going for speed or have boats with very small props, but for a scale modern sub, it tends to be an issue, as they have larger props and require lower RPM.

The kilo isn't as bad as some, as it tends to have a smaller prop than many of its contemporaries.

If you're looking to save space, one of these geared down 2:1 is all you need. That will give you a shaft speed of about 7kRPM, which i think is about right for this model.

You can use o-ring belts for a model this size, silent, simple and cheap.

http://www.hobbyking.com/hobbyking/store/__6312__hexTronik_5gram_Brushless_Outrunner_2000kv.html

Doubtful the boat can handle any more than about half a dozen watts without inducing handling issues due to torque induced roll from the prop. The motor above is rated at about 15 watts and is about the size of a five penny piece. You could with care, pretty much sink this into one of the end caps, so it almost became invisible.

nick_75au

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 257
  • Location: Brisbane, Australia
    • Logan City Marine Modellers
Re: Brushless motor advice needed...
« Reply #5 on: December 08, 2013, 01:02:16 PM »

Im pretty unfamiliar with subs power requirements ,


 I only have a TT Neptune that rarely sees the water hence the vague response,


 there are a new breed of brushless motors out used for camera gimbals, I have one sitting in my shed that is only 80 Kv and a short 25 mm long and 28 mm diameter, there are others with higher Kv


 I haven't had a chance to extensively test it yet, they have almost no protruding shafts so that needs replacing. so it is possible to have a low KV small motor
Logged

microgyros

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 208
  • Location: Glasgow
    • microgyros website
Re: Brushless motor advice needed...
« Reply #6 on: December 08, 2013, 01:09:57 PM »

The issue is space so you can make the maximum of the tapered hull portion with two servos and the motor in the wet.All you need in the watertight area is the esc,receiver,pitch control and battery.
 
This year I used a Kilo as a test bed for all sorts of ideas.One success was a similar 280 motor to the the 12 volt RE280/1 held by those plastic 280 clips that are sold in packs of ten.I had to tape up with alu tape and strengthen taped holes with a thin shell of glass coth and epoxy.This was a constant through some half dozen experimental water tight compartments plus waterproofed batteries.
 
I have a kit of o-rings now but silicone insulation from 14 awg cable sealed the 280 shaft and silicone fuel tubing sealed a servo shaft.I strengthed micro servos but 9 gram servos only need solvent welds and a spot of hot glue.
 
The motor to prop shaft coupling was a superglued plastic cotton bud.
Full load current drain with a 2s lipo was a quarter amp with oversised 25mm prop.
 
Brushless in a Kilo? Nah!
Logged

nick_75au

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 257
  • Location: Brisbane, Australia
    • Logan City Marine Modellers
Re: Brushless motor advice needed...
« Reply #7 on: December 08, 2013, 01:23:04 PM »

There's a few guys running brush-less out-runners outside the WTC, as RC subs are limited to fresh water this is only an issue for the bearings and ferrous parts of the motor  ok2
Logged

microgyros

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 208
  • Location: Glasgow
    • microgyros website
Re: Brushless motor advice needed...
« Reply #8 on: December 08, 2013, 02:26:00 PM »

If Richard gets as far as Tom trout-salmon's skipjack tuna he will then be faced with how to make the pitch control flip in reverse.
But I'm trying to help Richard with a solution that has been reliable and simple to fit,not give him one of the hundred different options.It is just a 3 12v 280 clipped into place but it saves so much time and effort.
Logged

microgyros

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 208
  • Location: Glasgow
    • microgyros website
Re: Brushless motor advice needed...
« Reply #9 on: December 09, 2013, 10:45:21 AM »

I've managed to get a webcam working.

I had this arrangement for a no hassle replacement but the Re280/1 was just the job.
Suppression capacitor,case and cable exits are insulated by glass fibre.The connecting wires lead to a 22 gauge servo plug.
A brushless in-runner or any other motor with the same diameter could be substituted in seconds.


 
Logged

U-33

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,338
  • K-157 Vepr. Akula-11
  • Location: Eastbourne, Sussex, UK
Re: Brushless motor advice needed...
« Reply #10 on: December 09, 2013, 01:46:06 PM »

Thanks for the advice Mike...much appreciated as usual. I didn't think of running the motor in the free flood area of the hull, something worth considering.
Logged
Rich

K-157 Vepr. Akula-II (project 971U)
---------------------------------------------------------------

~~~~~~~  "Motorflotes need love too...."  ~~~~~~~

MotorFlote build log : http://www.modelboatmayhem.co.uk/forum/index.php/topic,15222.0.html
Pages: [1]   Go Up