Electric Motors

The numbers on brushless electric motors vary so much between manufacturers that they are pretty meaningless. The only real way to compare motors is on:

• Stator dimensions (should be specified as diameter, length or height)
• When comparing motors of the same or almost the same Kv, look at the Rm (resistance). That determines how much heat will be generated. Copper loss = Rm x amps².
  • I² x Rm = copper loss (Watts)
  • Iron loss = Io x volts (Watts) ~ Io is no-load current.

It doesn’t matter if one motor is fat and short and the other longer and thinner. If the Kv is the same, the torque per amp will be the same.

Software Utilities

• https://www.ecalc.ch/
• https://www.scorpionsystem.com/support/downloads/

Below are the motors I’ve used/researched and information about their possible uses:

Turnigy NTM Prop Drive 3536 1400KV

Experimental Airlines refer to this motor as ‘the powerhouse’

Small stick (1100 span)

Turnigy aerodrive d3542/4 1450kv
70 amp / 3 to 5 cell
10x6 (52 amp draw, 580 watts)
10x7