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MR RF4 1/4 scale electric power setup

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Hi everyone

Hoping to get some help with regard to a electric power setup for my nearly complete RF4.

rf4 complete.jpg

I had originally thought it would come out weighing 9lbs, however it's looking more like 10.5lbs (still in the range suggested by MR)

So I had thought of 850watts power with a 5s pack, 750 kV motor, 70A ESC, prop size is 12x6 due ground clearance.

I'm thinking this is still going to give me adequate performance.

I think a larger battery pack is going to be difficult to accommodate.


Appreciate any thoughts other builders might have.


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Hi Martin,

The usual rule of thumb is 100 Watts/lb and this gives a distinctly "sporty" performance.

Your setup will give a little under 85 W/lb which should be excelent for a model like the Fournier.

If you have the exact motor/battery details you can put them into an online calculator such as ecalc to give you a reasonable indication of the thrust, duration etc.

Cheers, Pete

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Thanks Pete, appreciate your comment.

Steve, more pictures in the RF4 album, I'm sure it's public. How much did yours weigh in the end ?

Any other builders of this model go with electric power ? Would love to have your thoughts on battery, prop, motor etc.




Edited By Martin Fane on 21/06/2016 17:32:34

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  • 6 months later...

A fellow club member had one years ago with an 80s vintage OS 46, and the model flew in a very convincing fashion.

The figures you have quoted look very sensible, and will give good performance. You most certainly don't need (or really want) 6S for this model. Might I ask: what is the issue?

Kind regards,


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  • 6 years later...

Please can you help me?

I have a "second hand"  kit of this model.

But missing the parts list and building instructions.

May be you have building pics of your model?

Thank you


Kind regards


John Aarnoudse


The Netherlands 

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