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It's a wonderful time to be involved in electric motor power RC! Just a few short
years ago electrics were viewed as the inferior alternative to gas powered models.
Batteries were NiCd and motors were brushed, and often mated to gearboxes that were
louder than the motor itself. Today, high-discharge LiPo cells have helped make
enormous improvements in terms of gravimetric energy density, and brushless motors
have delivered improved efficiencies and longevity. But the most substantial improvement
has been the dramatic increase in the number of brushless motors that have arrived
in the last few years, as well as the broad arrival of the "outrunner" brushless
motor which has eliminated gearboxes in many cases.
The biggest problem a modeler now faces is quickly understanding how to best use
a new motor. While high-end motors come with data and some assurance of repeatability
between motors, many of the new ultra-low-cost brushless motors are only partially
specified or the manufacturing test flow is insufficient to catch out-of-spec and/or
improperly wound motors.
To date, a raft of excellent solutions have evolved to help the modeler understand
how a motor might perform when mated with a particular battery pack, propeller and
ESC. Some software assumes an idealized propeller model, while other software uses
carefully measured prop parameters to improve the accuracy of the results. Leaders
in this category include MotoCalc and Drive Calc, both of which are excellent pieces
of softare. MotoCalc has been helping folks understand the performance of the entire
aircraft system, even taking into account airfoils and drag estimates. MotoCalc
delivers to the modeler a clear English explaination of how the model will perform.
But once MotoCalc has told you your airplane won't fly fast enough, where do you
go from there? That was a question that hounded me as I focused on building high-duration
flying wings.
PeakEff isn't done. I'll continue to add and improve as time permits.
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