propshaft?

[Terry Chapman 2Participant @terrychapman2]

Hi Im new to building boats (normally aircraft?)

Im building a Diva and I wanted to uprate the propshaft,propeller and joint.

The one I have is around an 1" longer than the one supplied in the kit,Is it useable?

Also what batteries do I need for a 400 motor?

Many thanks.

[Terry Chapman 2Participant @terrychapman2]

[ashley needhamParticipant @ashleyneedham69188]

Terry. It rather depends on the room you have available if that’s not an obvious thing to say.

if you have not yet fitted the motor mount and can shift it up a bit then no reason why you can’t use the shaft.

Battery choice depends on the size of boat and the motor rated voltage. I have had no probs running Speed 400s on a 6 cell Nimh.

Ashley

[Malcolm FraryParticipant @malcolmfrary95515]

If the long shaft won't fit, shortening is feasible and, with care, fairly easy. Lengthening is the difficult part.

What 400 motor? They come in various voltage ratings which usually appear on the label. A 6 volt max motor will run very fast on a 7 cell battery, but not for long. An 8.4 volt one, on the other hand, will run reliably for a long long time.

[timgParticipant @timg12590]

Hi Terry

I built a diva last year and upgraded the prop shaft/UJ and prop and fitted the speed 400 motor as recommended (not 100% sure the right motor as Malcolm has already said about various differences) with a 7.2v buggy pk.

After a disappointing 1st run I fitted a different make of 400 motor unfortunately no real improvement, now looking at going brushless..

I will post a pic and measure bits if that's any help?

Tim

[ashley needhamParticipant @ashleyneedham69188]

A J Perkins 480 fits nicely in the same mount as a 400, it’s just a bit longer. It has a bit more poke in it.

1400Kv and 30A brushless motor/esc combinations are for nothing on e-bay, about £12 from a uk supplier, or dropping to £8.50 for 3 or more. Ok, forwards only, but a huge upgrade from a 400, and on a7.2 stick and 35mm prop, surprisingly frugal with the amps.

A 1000kv/30A setup has just been tried here and even with an x50 prop on it only takes12A. I think 8-ish A woulD be more likely on an s35 or s40.

Ashley

[Terry Chapman 2Participant @terrychapman2]

Posted by timg on 09/02/2021 16:20:46:

Hi Terry

I built a diva last year and upgraded the prop shaft/UJ and prop and fitted the speed 400 motor as recommended (not 100% sure the right motor as Malcolm has already said about various differences) with a 7.2v buggy pk.

After a disappointing 1st run I fitted a different make of 400 motor unfortunately no real improvement, now looking at going brushless..

I will post a pic and measure bits if that's any help?

Tim

Hi Bud,Ive fitted a 400 but its brushless if that makes a difference?

Thanks

[ashley needhamParticipant @ashleyneedham69188]

It makes a difference on depending on the motor spec.

Ashley

 

Edited By ashley needham on 10/02/2021 08:47:00

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