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Old Dec 30, 2012, 10:57 AM
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Moab, Utah, USA
Joined Apr 2003
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There is no comparison. Going from a 12x8 to a 12x6 on 4s will decrease your pitch speed to 75% with a modest drop in power consumption. There will also be some decrease in propeller efficiency. But any change in the airplane's performance, which will be slight but noticeable, can be attributed more to the decreased power consumption and pitch speed.

However, going from 4s to 3s with the same propeller will cause a drastic decrease in power consumption and airplane performance. The motor's RPM, and thus the propeller's RPM, is proportional to the input voltage. A propeller's load, and thus the motor's power consumption, is proportional to the change in RPM cubed. Therefore, going from 4s to 3s will decrease your RPM to 75% of the 4s RPM. This means your power will be reduced to approximately 42% of the 4s level.

You will definitely notice a difference in airplane performance.

Larry
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