Best Motors for Huntsman?

[Dean Pritchard 1Participant @deanpritchard1]

Hi All!

I'm looking to source the best motors I can get, to power my boat. I'm working on a replica of a 31' Huntsman. The hull is 42", made from GRP, and is quite a big lump! I was looking to fit twin MFA 850's, but I've heard that they are very thirsty on batteries! Therefore I am looking for recommendations from the forum. I

I want to get a good performance from the motors (ie; fast!), and I'm open to suggestions about battery combinations also. I intend to use twin 55mm 3-blade racing props.

If I can progress this, I can get '707' ON the water within the next few months

[Dean Pritchard 1Participant @deanpritchard1]

Sourcing the best motors for ‘707’

[ashley needhamParticipant @ashleyneedham69188]

Dean. I like the 800`s and 850`s, and an 850 will turn an X50 prop at 10A ..not sure if this is regarded as power hungry. More performance could no doubt be obtained by other motors hower the twin 850 combination will push the boat along at fair rate and not sound too buzzy with it. (at 12v, use a |Nimh for less weight)

Ashley

[Dean Pritchard 1Participant @deanpritchard1]

HI Ashley!

Do you think it would be advisable to fit cooling coils to these motors? I already have water scoops, and tubing?

Dean

[ashley needhamParticipant @ashleyneedham69188]

I wouldnt have thought they will run hot, as long as there is a bit of air going through the boat, its a big hull, and the props are the right size for the motors.

Ashley

[Paul TParticipant @pault84577]

Hello Dean

At 42inch it's also going to be heavy and ultimately the motors will have to push this 'big lump' fast enough to get it onto the plane.

Don't underestimate the all up weight of the model when choosing the motors, as Ashley said the MFAs are power hungry and at 10A per motor they will eat up small battery packs very fast and using larger batteries will also increase the weight.

It might be worth considering brushless motors as they are far lighter than the big brushed motors and are capable of producing far greater power.

Good luck

Paul

[ashley needhamParticipant @ashleyneedham69188]

I think 10A per 850 is reasonable considering the power they produce??

My Fantome runs very nicely on the 800`s and they take about 6A each.

how fast do you want to go?? anything much faster than a pair of 850`s will be sucking up the juice. Brushless is of course possible….but what type/model.Kv….?

Ashley

[Dean Pritchard 1Participant @deanpritchard1]

hI Ashley, Paul!

Sorry for the delay- I've been on ho;s, so haven't been in my office!

I have looked at some brushless motors, they do look expensive, but also want the performance. I would like to bet the boat up on the plane too. I am unsure about the battery set up as yet- maybe NimH packs would suit the best, as I am looking to reduce weight. I am still looking to use the twin 55mm race props, I have just ordered the A frames for the prop tubes, Once everything has been decided, i can continue the build!

Thanks for your advice!

Dean

[RedbunnyParticipant @redbunny]

Hi, Dean take a look at fitting two Hobby king 830 kv brushless outrunner Donkey motors , they are not expensive and one gives out the same power as a 40 size glow motor, there open design means they run cool and you could use 3s lipos and save bucket loads of weight, you would be better fitting water cooled escapements.though for fast runs.

Redbunny.

[Dean Pritchard 1Participant @deanpritchard1]

Cheers mate- these are on order! Just a question on speed controllers- will I need 2? I want the speeds to be synchronised so both motors run in tandem

Any Thoughts?

Dean

[ashley needhamParticipant @ashleyneedham69188]

As per a previous thread, brushless motors have to have a speed controller each, no sharing.

Buy a program card at the same time to program up the ESC, indispensable. There are loads of brushless ESC out there, mostly aircraft ones with no reverse..if this is not an issue, then these will be ok but will need a cooling breeze likely, or get a watercooled one of course.

Any idea how many amps these motors are going to pull?? More than the 20A that a pair of 850`s pull?

It is a fact that ALL BRUSHLESS motors make boats go faster than brushed motors, as everyone who fits them fits really powerful ones and so their boats go very fast…..proving that brushless motors are better

Ashley

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