Hi Ivor
Thanks for your message. I had considered the inside 'lip' to small to make a difference.
As F16_guy points out, the Viggen has F16 intakes rotated 90 degrees to the sides of the fuselage, (and a big motor).
So, do the variable ramps, in a Vigilante or Eagle, perform better off design point than fixed geometry and hence the Viggen intake was designed to function best at 2 speeds?
Regards
Mark