Thread: Discussion MJX-F45 Single Rotor FP
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Old Oct 07, 2012, 08:26 AM
Stoersender is offline
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Germany, BW, Göppingen
Joined Aug 2012
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Originally Posted by BThirsk View Post
A carbon boom will lose a little weight. The plastic fines are lighter than carbon.
I just weighed the brushless motor and the blade holder at 16,grams.
The stock motor is 13grams by itself. That does not include the weight of the jack shaft and gears, so I don't see weight as an issue.
I've drafted two holders for now.
The first one will use the original holder + epoxy so that the new motor fits right into the old gearbox

The idea I'm planning to use right now is, to create a new holder from scratch. I calculated it's volume and then the weight.
It'll be 7-10gr heavy, depending how thick it will be.

I also considered the zero gravity line of the motor + prop:

So everything is aligned to the horizontal axis and perfectly balanced out.

I've caltulated the weight like this:
  • motor 20gr
  • prop 5gr
  • holder 7-10gr
gives a total of 32-35gr

This stands against the weight of the original motor + gearbox + prop: 20gr
Total: 12-15gr heavier.

Using a carbon tube for further weight reduce:

Stock tube weights 12gr.
Carbon tube weight depends on the dimensions.
Found tubes around 5-11gr
This results in 1-7gr less weight.
At best the tail motor mod will make the heli around 5gr heavier (desregarding momentum and that stuff... to complex for a quick weight overlook)
In practice I would say, that with a carbon tube, the total weight gain will be about

So for now I'm relieved
I hope everything works out how I plan
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