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[Martin13]

Hi Guys,

I am scratch building 1/16 Scale Brave Borderer 1800mm long from marine ply. The boat has three props and I want them all operational.

In planning the internal structure etc - how do you calculate what size motors to install ??

Martin
from Down Under

[Shipmate60]

Fron experience and someone who builds this size of model.
 3 x Graupner 700 Turbos.
These are very power hungry, but will power your model well.
OR
Going by the RAF Launch on here 2 x 800 turbos (or might be 850's)

Bob

[Martin13]

Thanks Bob,

As an interim inquiry, what would you recommend for battery power seeing that space is not an issue.

Thanks again

Martin

[Shipmate60]

Martin13,
These models are about the size of yours and seriously heavy, but perform superbly. Here is his email to me:

Hi Bob,
For my fast crash boats and torpedo boat I use Graupner 700BB turbo's with
Electronize 30 amp. FR30HX speed controller, I use props from the Prop Shop,
they are good.
Hope this helps.
By the way, the battery's are Ni-MH 13amp cells bought from Eurobatteries,
this is bought online, as these motors are thirsty for power a good set of
batteries are required, the drawback is that they are VERY expensive.

Bob

[cos918]

hi martin i got some 700s for my boat when i tyred them out in the boat the load was +15ah at full power thats 12v . the power the boat had was immense her props were 55mm 5 blades. I changed the motors to protech 720 . The reason i say this is for your boat to run at full power for one hour your going to need about 35 to 45 ah .Thats a hell of a lot of battery and weight. john

[Martin13]

Thanks Bob, Thanks John.

The model has 3 - 50mm, 3 blade props.

At least now I have a starting point.

Thanks again, your input is much appreciated.

Martin
Down Under in Aussie Land