OK, where do you place your ESC ? I'm guessing most put it in the fuselage somewhere but I've seen it in the duct tube and behind the motor.
So where is your ESC ?

anywhere I can get good air across it for cooling, I have never had one installed behind the fan though???
I have a twin with the esc's in each wing and a scoop for air into the wing on the bottom and a scoop on top to let air pass, both wings..

on my F-16 its in the duct for cooling and in my EDF FOX its in the very front

Two Reactions are shown, One powered by a Wren 44 and the other by EDF.

The EDF is the blue, yellow, green plane. The black area on the top of the body above the wing is where the ESC sits flush with the body. Very cool running. The ESC is a Turnigy 100 that pulls 62 amps from 12s 5000 driving a Turnigy 4.5 fan. Plane weighs 14 lb with retracts, flaps, and brake.

I've had both in the duct and outside the duct.  I'm beginning to wonder if hanging the esc in the duct may actually be detrimental.</p>

Two things I'm seeing on a duct mount. One the esc could be screwing with airflow, causing a turbulence issue. And two the esc is exposed to high speed airflow, you ingest something and it hits the esc and could cause some problems.  Swallow a June bug/ beetle or other hard shelled insect and I could see an impeller exploding and blowing back into the esc.  Fan is cheap to replace compared to an esc.  </p>

My F-20 exhaust tube looked like an insect debris field after only  a couple of flights over a meadow.  Blades had all kinds of remnants on them.</p>

And I thought only gassers needed clean up after flying.</p>