Al,

I think you are on the right track. The first set of VG's were probably still in the boundary layer. They won't work unless you are entraining high energy air into the BL. You could probably tell by using the soap or dirty oil trick to see how effective they are at mixing the air ahead of the inlet.

Other than a diverter, or a bleed of some type, I can't come up with any clever soloutions to solve the boundary layer injestion.

If you want to just live with the boundary layer injestion and have a purely internal soloution:

You could try a mixing vane. It would be just like Ernest's vane except with large ripples in it. Think of the lobed exhaust mixers on a jet engine. The idea is to have alternating jets of high and low energy air. This could help homogenize the flow and with TJ's re-contour stop the seperation problem.

Monty

Monty; you may well be right; it may take a combination. However, I did put VGs in front of the entrance, and it did not make a noticeable difference. They were only about 8” forward of the entrance because of the gear well that is there. I think I will try again with them further forward – on the gear door covers; and make them a bit taller this time.