I have a Hummingbird with brushless main and tail. The main was getting hotter than I liked after 7 minutes even after adding a heatsink. About 150 degrees.

I remembered seeing a setting for timing in the Phoenix menu and changed from the second setting (normal), to low timing (less power, more efficient) and ran again the exact same duration and checked again:

122 degrees!

Apparently, high timing for more torque, low for more speed.

Since the motor has more than enough power with the 3 cell Lipo pack, I don't notice a bit of difference except a lot cooler motor.

Just an idea.