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I want to build a RC ultralight

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I want to build a RC ultralight

Old 08-04-2019, 06:43 AM
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Default I want to build a RC ultralight


I aim to build a RC ultralight. I will use what I have so far: a 10x5 wooden pusher prop and a 1000KV brushless motor and its ESC.

I have built a FliteTest Simple Cub so far (and it flies pretty well!). My chosen design is this one, the Rans 12 Airale (just because it will be easy to hide the batt and electronics):


what about building the wings with a good dihedral and use only rudder?

Is there any section where I can find info about RC ultralights?

Thanks, Robert.
Old 08-04-2019, 07:07 AM
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Originally Posted by rva1945 View Post
... a Kv=1000rpm/volt brushless motor and its ESC. ...
Can't help you with plane design, but ..
Motor max. current and max. power?
Battery voltage?

Note that Kv says absolutely nothing about max.power or max. current a motor can handle, or about max. torque. A 1:1 train motor and the motor in your toothbrush can have the same Kv.

It's all about what the motor wants/tries to do versus what the motor can do.
Kv matches rpm and voltage, there's nothing more to it.
  • Kv and voltage determine how fast motor wants/tries to run
    (rpm_noload = voltage Kv).
  • Rpm and prop determine torque, which in turn determines current
    (current = torque Kv, in SI units!).
  • Max.current and power determine whether that battery/motor/rpm/prop combo can run without going up in smoke.

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Old 08-04-2019, 07:21 AM
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I will use 3S lipos, 1300-1500mAh. I measured the motor with a 9x5 prop at almost 800gr.

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