Choosing motors

Sorry if I appear to be hogging this forum but here's another question.  There's a wide variety of brushed and unbrushed motors but the supplier's websites don't give much help in choosing between them.  Telling me about rpm and torque and amps does not really help.  I am building a 36" model Nile gunboat so it will be fairly heavy but does not need high speed.  So I think a brushed motor should be fine - but which size/make?  Is there a guide to how motors are classified?

Hi, not hogging at all....  A couple of questions to help decide on the motor.... 

What diameter props are you planning to use & what voltage battery will you be using to power them..

Mark..

A 40mm prop powered by a 7.2v NiMH battery - same as in my Caldercraft Puffer.  And the puffer is driven by an ancient small nameless brushed motor which seems fine.  I also have a Graupner Speed 600 but think that is intended for much faster models.

Hi, sorry for the delay replying been a bit busy... Anyway, I would go for this one https://www.componentshop.co.uk/540-standard-dc-motor.html   probably a little bit over powered but that is why we fit ESCs 

Mark..

Mark - thanks - is that motor compatible with a Marine 15 ESC?

Hi, yes that ESC will be fine & fit a 10a fuse....


Mark..

This is a common question asked....

And before I answer I need more information....

How many prop shafts?

What type of battery do u want or can u fit?

How big of a prop are you using? ( this ones vital as bigger props give more load hence require more amps)


Get back to me if you want a few other suggestions.

Although a standard 540 motor on a 15 amp esc will be fine for most props up to 40mm however one alteration to the advice given do not fit a 10 amp fuse between the esc’s positive power and battery, instead fit a 15 amp fuse.

540’s tend to initially draw up to 11 amps when first started so a 10 amp will blow right of the bat when the boat is under load ( put in the water) bench testing with. 10amp will work fine as there is no load on the prop just open air! Be aware.

A 15 amp fuse will be totally fine to help protect the esc as mtronics esc’s have a built in overload and are able to handle a little extra amp just incase ( burst current)