Advice Sought

[Ian Harrison 4Participant @ianharrison4]

Motor for

[Ian Harrison 4Participant @ianharrison4]

Hi, Can I please ask for advice on what motor would be best for my old 34" wooden "Wave Princess". Rather heavy and used to be powered by an ED 2,5cc Hunter Diesel. The boat needs refurbishing and of course I would like to fit a standard brushed motor upto 12v. I would like the model to plane. I have a 777 motor fitted within my old 34" Crash Tender which goes well but understand they are no longer available. Any advice would be appreciated. Thanks.

[NoelParticipant @noel26080]

An MFA Torpedo 850 did the trick for me in my Wavemaster that I finished this year. Runs at 12v, planes well and doesn't get too warm. 35mm two blade x prop.

[Ian Harrison 4Participant @ianharrison4]

Cheers Noel, it is great to get actual practical advice.

[ashley needhamParticipant @ashleyneedham69188]

The 850 is ok up to an x50, but you are not likely to need such a big prop, The 2 blade types are very cheap and perhaps a small selection round the 40-45mm size in X and S form would allow you to experiment to get the best performance/current draw.

Ashley

[Dodgy Geezer 1Participant @dodgygeezer1]

Out of interest, what size (or type) of brushless would you fit to such a boat? I have quite a few old Aerokits needing restoration…

[Ian Harrison 4Participant @ianharrison4]

Thank you Ashley, good advice and an interesting point about the brushless motor. I put a 777 motor in my Crash Tender because I was not able to get any proper information from the model shops, it was a case of trial and error, but at the serious costs that is not really possible. So any answers to this question would be interesting.

Thanks to all and best regards.

[Dave MilbournParticipant @davemilbourn48782]

CEM 750 motor is suitable for Aerokits Sea Commander, which is more or less identical in size and hull shape to Wave Princess. **LINK**

777, as far as I can remember, was a slow-revving high-torque motor.

Dave M

[ashley needhamParticipant @ashleyneedham69188]

Brushless motor selection:

The way I look at it is…..a 28mm motor is good for anything up to 40 ish mm prop, 35mm motor anything above (but not ridiculously large, say 60mm).
Choose the sort of power you want to have, decide on the revs, decide what battery (voltage) you will be using and hence determine the Kv of the motor (revs divided by volts).

To my mind this gives a starting point. Motors in any one size come in a variety of power ratings and the lower Kv ones have more torque, and the price varies somewhat. Turnigy do quite a range of motors of good quality and price, for instance. I have been using Fusion motors, also quaite a good make, but there are very cheap smaller ones on e-bay and these seem to work well enough.

Ashley

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