One thing I did not test today was using a different prop. Mike Scott was out flying today with his Cobra 2826/10 930Kv 4S Edge/Hubin set up in an airplane a little larger than mine but almost the same weight and his motor temps, with a tightly cowled motor and minimum exhaust air outlet was running motor temps about 105 F. He was using an APC 12 x 6 cut down to 11 3/4 at 8900?rpm, while I'm using an APC 13 x 5.5 cut down to 12 running at 9600 rpm. Next time out I'll try using a 12 x 6 cut down like Mike was flying. I could be running a prop that puts too much load on the motor. We'll see.
I appreciate everybody's input and maybe we can all learn something together getting through this.
It looks like you have tried the easy cooling suggestions except the turbo spinner, and have moved to the other end of the problem, heat generation. I was hoping to see some of the variables other than just prop for comparison. Mike's variables, particularly amps/watts and the factors contributing might be enlightening or, differences between your current plane and prior where you used the same motor, prop, batteries.
With more weight/wing loading, might you be using more gain rpm or time in gain on the Igor setup vs Hubin and then more watts used.
Thanks, just trying to learn as you suggested.