Interesting stuff, Pierre, tracking oil on an air frame to see what's going on with air flow.
A while back I had a few very thin streaks of oil coming up over the windshield and tracking them forward discovered they were coming from inside the cowl via the inlet from a leaking PSRU which meant there was air coming out of the cowl in that area. You'd think the oil would be all over the top of the engine but it wasn't, it was on the windscreen, the engine was dry.
It could be with a fixed cowl inlet, there is a point in the speed plot where internal cowl pressure is such that air can't all go aft, down and out, so pressure builds up and it burbles forward and up and out.
For a few million, maybe we could engineer a variable inlet. I wonder what that lucky family in Winner, SD is doing with the $220 million they won a couple weeks ago?
