Hi,

What wingspan has the "unknown" plane (I have not seen that posted).
Edit: It was posted in first postI can see now: 64.5in wingspan.

Then it is probably not Atomic since it has wingspan of 1500 millimeter / 59 inch.I see Atomic was designed in 1974 and had down swept stab, ratherunusual already in 1974, Hanno Prettner was one of the first in top pilots as far as I know to have that in 1975 with hisCurare, that he started to fly with in competitions that Year.

/Bo