Mailing list for discussions on designing and building brushless electric motors and controllers. The motors built so far, range from 20W to 2kW. You can also build from kits. LRK and CD-ROM outrunners have different winding diagrams!
Outrunners are inside-out motors, the coils are stationary, housing and magnets rotate. They feature a high torque AND they can rev. There is no need for a gearbox, which means less weight, less $$$/€€€'s, no losses, no whining and no wear. The motor can swing a bigger prop, resulting in a higher overall system efficiency. The builder can tailor the motor to the application by adapting the number of winds. (Motor pictures by Detlev Koch)
If you are designing your own motor, you can use FEMM to simulate the motor and calclulate the KV, there are tutorials on how to do that in the FEMM examples.
You might be wondering what the use of Kv is, if it doesn't tell you the RPM under load.. Well, Kv is one of the 3 motor constants that's used to simulate a
The Kv rating is the constant relating the motor's unloaded RPM to the peak (not RMS) voltage on the windings. E.g. a 100Kv motor will spin at 600RPM on 6V,
What is the significance of RPM per Volt? Is this RPM that would be achieved with the bare minimum load at the maximum current flow dictated by the windings