On Friday, April 5, 2019 at 5:41:00 AM UTC+3, Andreas Maurer wrote:
On Wed, 3 Apr 2019 07:20:42 -0700 (PDT), Steve Leonard
wrote:

On Wednesday, April 3, 2019 at 1:53:19 AM UTC-5, krasw wrote:
ASW 20 was ahead of it's time and in reality belongs to same generation as Ventus/LS6 (except that final bit of wing loading). ... All Wortmann FX170-profiled gliders are older generation performance-wise. If it rains or you get bugs on leading edge, you fall out of sky like an anvil.

But, the 20 uses the older (and maybe better?) 62K153/131 family. Maybe that is why it was ahead of its time? Because it used an older airfoil section. Like its big brothers, the ASW 12 and ASW 17.


Interesiting side note:

Luc Boermans recently told me that ALL his airfoils are based upon the
FX 62K-131 of the ASW-20.


And I read somewhere that when Lemke designed LS6 profile the upper surface was more or less taken straight from FX62. Of course the lower surface of modern profiles is more refined, in 70' you could not even dream about stretching laminar flow to almost full chord length.