On 3/16/2021 3:49 PM, Eric Greenwell wrote:
...I'm willing to accept the current claims by Schleicher, Schmepp-Hirth, and Jonkers.
... I am also willing to accept GP's numbers as being close to reality.

Based on what - magical thinking?
Because others claim something similar but also have not demonstrated?

I did not go to Poland, but dealer (Tom Holloran) did go to Poland and
fly a GP15. Apparently, he thought it was a very good glider, as he
became the dealer, and one of the first few will be his glider.

Been there, done that. OK it was Germany not Poland ;-)