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Old Dec 30, 2012, 08:08 AM
Nereth is offline
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Lowering pitch vs lowering voltage - differences in power system behaviour?


Quite simply:

If you have a 12x8 prop running on 4s and you want to lower the max speed, then you have two ostensibly similar options:

12x6 on 4s


12x8 on 3s

Which would be more energy efficient from the battery at the same speed?

Additional info:

At 12x8 on 4s, the ESC is near its limit, the battery is at 80% of its C rate, and the motor is ~at its practical current limit. I have more accurate numbers if necessary but I want to keep this discussion general if possible so it can be more useful to different people and situations in future. If more info is needed even to give a decent generalised response, please let me know.

For completeness of discussion it would be good to discuss the parameters of either system at full throttle steady state, partial throttle steady state, and during acceleration/low speed where pitch becomes interesting. It might also be interesting to compare to 12x8 on 4s at 75% throttle.

My own understanding:

A few months ago I would have said 12x6 on 4s, but now it's somewhat up in the air due to what I learned in a previous thread regarding pitch and prop efficiency. I don't feel my understanding is strong enough ATM, so I will wait till I can think about it more and maybe read some responses before I contribute too much personally .
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