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Author Topic: HELP! brushless motors for big tug  (Read 2673 times)

Jerry C

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HELP! brushless motors for big tug
« on: February 05, 2012, 09:55:37 AM »

I'm having a bit of trouble deciding which motors to use for my 2 metre Abeile bourbon build, I have exchanged messages with Nick75au (advice much appreciated thanks nick) and he suggested I think about a motor that is roughly 160 kv at 12 volt, sounds good but im having trouble sourcing this type of motor, either not in aus or out of stock overseas.
What I do have access to is a Himark 250 rpv 33-48volt, I already have 2 x 120 amp hawk speedies that will handle the voltage (I have two himark 510kvs in a 1600mm tug at 12 volt on 55mm props and works great)
I should also mention that it has 4inch 4blade props, I would like direct drive but I dont think thats going to happen so If I went with the 250rpvs would they handle the job and what sort of belt reduction would I need.
Im still new to the world of brushless so Im hoping you guys can assist.
By the way I also like stupid ammounts of power in reserve.

nick_75au

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Re: HELP! brushless motors for big tug
« Reply #1 on: February 05, 2012, 10:06:53 AM »

http://www.hobbyking.com/hobbyking/store/__18182__Turnigy_Aerodrive_SK3_6374_168kv_Brushless_Outrunner_Motor.html

In stock ATM

My favourite hobby shop ok2

Probably will get one of these myself soon Got a 1/48 FFG HMAS Sydney on the way from another (Ex Tasmanian) Prop is 120 MM diameter :}
I.ve ordered from a mob called Econobelt in the US very good value
http://www.econobelt.com/

Nick
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Jerry C

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Re: HELP! brushless motors for big tug
« Reply #2 on: February 05, 2012, 10:20:10 AM »

Thats it then nick , you are now officially my got to guy for brushless advice, my speedies start at 14cell nimh so I planned to run atleast 24v, which works out at about 4032 revs , is this to much for direct drive? I do like alot of power (don't like smoke though) oh and the model will weigh about 90 kilos

ayrshire andy

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Re: HELP! brushless motors for big tug
« Reply #3 on: February 05, 2012, 12:13:18 PM »

WAY TO GO MERMOD!  :D  Good to see models especially tugs being built with oodles of power, with your proposed setup you will have left watts far behind and be well into counting in shaft horsepower...just a little suggestion from a fellow brushless fan, have you considered installing some relatively cheap resettable circuit breakers to protect those gorgeous speed controllers/motors? Here in the UK at least you can easily find ones rated to trip at 100 Amps and they are of course rated 230 - 250 Volts for use in our fuseboxes....might they be suitable? Electrical experts give us your thoughts please!
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unicorn

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Re: HELP! brushless motors for big tug
« Reply #4 on: February 05, 2012, 01:43:53 PM »

 :-) :-) :-) :-)
   
             Have a look at the last posting on Big Bertha in the Model Tug Forum . com 

                                                                                                            rgds    unicorn
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Xtian29

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Re: HELP! brushless motors for big tug
« Reply #5 on: February 24, 2012, 10:03:25 PM »

Hello

So Mermod, have you made your motor choice ?

I'm quite in the same trouble, searching for brushless motor for my Invader Class tug running 5 blades 10cm propeller.  Any advice ?  Hobbyking is also my favorite hobby shop but so many kind of motors  %%

Xtian 
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AT Boatyard

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Re: HELP! brushless motors for big tug
« Reply #6 on: March 10, 2012, 09:49:57 PM »

Hi Mermod,good to see you are coming over to the dark side !!!!!
I have a 300kg 16 foot type 45 running on brushless work very well
I put brushless in a wyeforce about two year a go.lots of fun and only on 6volt lodes of power though.
Have a look at these video,s

http://www.youtube.com/watch?v=hTR5g_jO7sk     tug

http://www.youtube.com/watch?v=xto1Lrca56A       type45

kind regards
Alan
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Jerry C

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Re: HELP! brushless motors for big tug
« Reply #7 on: March 11, 2012, 08:49:26 AM »

Hi alan, yours was the first post I went to when I started to look at brushless motors for the big girl, love your work

nick_75au

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Re: HELP! brushless motors for big tug
« Reply #8 on: March 12, 2012, 09:58:07 AM »

Th biggest problem is finding a very low KV that is not monstrous, for the 100 MM + props 1500-2000 RPM is enough so most motors will need to be geared down.

A well known supplier here runs a 700 brushed motor on 12 volts with an 11:1 planetary gearbox for excellent results on a 40 Kg model with a 100 mm, a similar brush-less motor of 1500 Kv and rated about 250-500 watts with a similar ratio box will have sufficient power, because regardless of the motor used, if the rpm is the same at the prop, for the same prop, the amps will be similar, there is a slight efficiency increase in running a smaller fast motor geared down but for our purposes a big shiny motor ;D looks better and the lower efficiency will probably not be subjectively measurable. A 500 Kv geared 4:1 would work as well. Just got to aim for the 1500-2000 RPM by calculating voltage * KV / reduction ratio

Nick
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mermod

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Re: HELP! brushless motors for big tug
« Reply #9 on: March 28, 2012, 11:45:54 AM »

I was just wondering, in order to avoid gearing, could I use the 168kv motor on 24v (giving 4032rpm) and use the dual rate switch on that channel to cut it down by half, leaving the rest like a kind of turbo, or instead of going 2x 12volt batteries should I use three 6 volts giving 18v total (3024 rpm) and just go easy on the throttle?
It would be easyer to just use 12volt but my speedies have a minimum of atleast 14cells nimh.
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