Oh my goodness! Now that takes me back! I studied swept forward wings for my dissertation back in 1988. I cited the Hansa Jet, Ju287 and the X-29 as practical examples of the wing platform. I built two wings, one swept back, the other swept forward at the same angle, and flew them in a wind tunnel. They had a NACA 0012 aero foil that I carved by hand (took me a whole term to do). I remember at least one research paper coming from NASA on microfiche (who’s heard of that these days?). It was considered very daring to actually write to NASA to get stuff, but I remember thinking ‘nothing ventured, nothing gained’. The work itself is lost in time (my ex- wife got rid of it as well as the rest of my engineering work and a huge swathe of my maths degree in a fit of pique), but I remember the FSW gave 15% less drag and 10% more lift over the conventional wing, as well as a massively reduced stalling speed. This almost stall-proof property without the need for wing fences, dog-teeth, etc is what makes FSW aircraft so attractive. The tendency to flutter, twist and come off is what makes it unattractive.
As I recall, the main reason for the Hansa Jet’s platform was that it put the wing box at the back of the cabin, giving a longer and clearer passenger area, rather than any aerodynamic reason. I think it and some gliders like the Blanik are the only aircraft with that planform to reach actual production, but it’s so long ago that I’m happy to be wrong.
Isn’t it amazing how something can trigger such vivid memories? And where did that time go?