I added an outlet just for motor air, and I managed to fly yesterday and today.
With just the outlet, the motor was cooler than the Cobra, but still hot enough to be worrisome. Based on advise from Paul Walker I added some NACA-ish inlets to the side of the cowl, blowing on the motor. While I was adding the inlets, I noticed that I had failed to modify the baffling from the existing front scoop to match the new motor position -- so I fixed that, too.
This brought the motor temperature down to somewhere in the neighborhood of 50C. This is according to a phenomenally cheap Harbor Freight thermometer -- so I'm not sure I believe it. But the measurement is backed up by calibrated fingertips -- I can touch the motor and hold my finger on it, which is about 50C. Moreover, it starts cooling immediately after the flight, where the Cobra would continue to heat up on the outside of the motor, indicating that it was _really_ hot inside.
I decided that my attempts at NACA inlets were ugly, so I made metal covers for them. Hopefully these will generate even more airflow over the motor -- and they'll definitely cover my woodworking sins. More testing as I get a chance. I'm hopeful that I can start actually practicing flying with this thing, rather than just piddling with the power system.
At this point I'm going to do a few more test flights to check temperature, then start actually flying. I have a spinner that Howard Rush made for me to fit my backplate, but I haven't yet assembled it. I'm a bit concerned that it will block some of my cooling air, so when I do get that done I'll be testing it, and then I may end up making some holes in it for airflow.
I did expect that I'd have a learning curve switching to electric. I did not expect that it would be this steep and this high at the beginning!