Heat management (1)

The heat management of the motor is essential for an effective use of the energy. About 50% of the electric energy is wasted into useless heat. The heating of the motor and components reduces their efficiency and causes more loses (resistance).

There are mainly 3 components which dissipate the heat:

• motor
• ESC
• wires

My strategy is as follows:

• reduce the thinnest wires (ESC to motor) to a minimum
• increase wire diameter from battery to ESC to a maximum 
• have the ESC cooled externally
• have the motor cooled externally

The result is that I changed the battery cable to and placed the ESC on the motor rod. This reduces the wire length from ESC to motor and gives the ESC a cooling from the air flow of the propeller.

I also installed some additional propeller blades to cover the center of the 40" propeller.
The cooling of the motor was really bad before, as the direct driven motor does not get a good air flow from the 30" or 40" propeller.
With the additional 2 small blades (about 10", from a helicopter), I cover just the center of the propeller. Looks cool (and it is) and should give 500g more of thrust :-)
You can see the ESC (red circle) and the additional blades (green circle). The propeller is still well balanced after the change.