On Sunday, November 10, 2019 at 5:49:28 PM UTC-6, Charlie Quebec wrote:
VNE is certainly tested by the German manufacturers, and part of EASA certification You appear to be using the method applying to powered aircraft in the US.
The flight manual of all Euro gliders clearly states all the operational speed limits.

Not really; Vd (or Vc) must first be determined before Vne is set. Vne is not discovered by testing (Vne is simply a fixed fraction of Vd to build a safety margin), and of course gliders are flight tested within and beyond the flight envelope. I referenced JAR-22, Joint Aviation Requirements that EASA (including Germany as part of the EU) abides by (JAA responsibilities are/were absorbed by EASA which still follows JARs). Here's an informative German publication : http://journals.sfu.ca/ts/index.php/...e/view/193/178