Greetings:

For the last five years, and until very recently I owned Ventus 2c
serial number 51. A friend owned a Ventus 2c with a serial number in
the low thirties. His owner's manual says best L/D is obtained with
a flap setting of 0. My owner's manual says best L/D is obtained
with a flap setting of -1. In comparing the two manuals, as best as
I can remember, it did not appear that the difference was attributable
to a "typo". My sense, (i.e., only a guess) was that Schempp-Hirth
did some additional testing and updated their owner's manual to
reflect new flight test findings.

John O. Graybill