Re: NACA Inlet question
Thanks Don, Roch, and Todd. Three in the plus column; no negative (so far). Thanks too, Bob -- you make four.
I did try VGs ahead of the beginning of the ramp but when I designed and placed them in accordance with this Kitplanes article (https://www.kitplanes.com/vortex-generators-for-cooling/) they were honkin' huge and wound up being mounted on the speed brake. Totally unsatisfactory but they did improve airflow somewhat. I'd like to see a picture of others' VGs if they are effective.
My oil flow tests show outflow at the inlet with air spilling over the little "strakes". Maybe it would be worse without them, maybe not. I'm tempted to take Bob H's advice and cut them off for comparison.
Bob, you have an O360 Long-EZ with no particular cooling issues, right? Maybe we can talk.