Brushless motors?

[Phil BrowneParticipant @philbrowne39943]

Please point me in the right direction if this has been already covered.

As an aero modeler I am used to brushless motors and I like them. New to Boats I would now want to use brushless setups in boat models.

But how do I work out what motor, battery, esc and prop size for a particular boat size . In planes you try and match the power to the weight of the model. Any tips for boats?

Edited By Phil Browne on 16/01/2013 17:34:47

[Phil BrowneParticipant @philbrowne39943]

[Keith LongParticipant @keithlong89920]

Hi Phil

Can't help with info, but if you look top left of the page just under the "Model Boats" title, you'll see a white bax maked search this site. Putting "brushless motors" in that and hitting search turned up 6 forum threads that might give you the info you're after or at least help you to work out what other questions to ask.

I do know it is something of a black art sizing motors to boats.

Keith

[ashley needhamParticipant @ashleyneedham69188]

The best way wouid to be to look at the setups in a boat similar to the one you are making (or are proposing to make) and use that as a basis. Despite a guide of sorts in a special not too long ago etc etc it is, as Keith says, a black art.

It is compounded by persons wishing to over power their boats regardless of scale, or those aiming for duration at the cost of speed..all these things come into play.. and as for which brushless you should use !!!! unfortunately brushless motors do not fall in the "can size" bracketry that brushed motors are or can(!) be grouped in. Although this is not a specificaly accurate guide to power or use, it gives a starting point.

Factors for choice could include the boat type, prop size for the boat, prop speed , battery voltage likely to be used (and this will give you a Kv starting point) and then decide on the developed power you would aim for.

Ashley

[Phil BrowneParticipant @philbrowne39943]

sounds like a world of pain I plan to build an aerokits sea nymph as soon as the kit arrives.

I already have 2 or 3 cell lipo batteries and a 1200Kv motor and a 30amp aircraft ESC (no reverse). I guess I will experiment with these first as I already have them and take it from there

[RedbunnyParticipant @redbunny]

Hi, Phil, if you look on RCgroups forum you can find links to Brushed to Brushless conversion charts.

The Sea nymph would be a good performer with a Graupner 380 or 400 brushed motor and go like stink with a speed 480 brushed, the matching brushless motors to these are a lot more powerfull, Ebay has loads of them, if you use a car esc you will get reverse,.

The prop problem is the same as aircraft ie pitch = heat try 30mm and 35 mm Standard 2 blade props to start with, a watt meter is a help, i myself would avoid X pitch props

Good luck with your Sea Nymph, i am restoring a 1958 Sea Rover wreck off Ebay, i am using a 600 Johnson brushed motor costing £2.97 new of Ebay, i have found nothing wrong with these but some people call them.

Gordon.

[Phil BrowneParticipant @philbrowne39943]

Thanks Gordon but the sea nymph is finished. I struck lucky with the 1200kv motor and it runs a treat. I found a you tube video of a sea nymph running this motor on a 3 cell lipo so I just copied this setup

here is my nymph

No reverse though but on this small model I dont think its needed

Edited By Phil Browne on 06/03/2013 22:37:51

[Phil BrowneParticipant @philbrowne39943]

I will have a look for the convertion charts as it may be useful for my next project. I already have the hull planked up

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