At 07:27 27 March 2020, wrote:
Hi Ruediger,

there is a drawing from Grob, specifying the turbulator location for
the
si=
ngle-seaters as follows (distances measured on the pressure side
of the
win=
g from the trailing edge to the trailing edge of the tape):

Wing root: 360mm
Inboard end of the aileron: 300mm
Wing tip: 178mm

Twin I and II twoseaters receive the tape only at the ailerons with
the
fol=
lowing dimensions:
4300mm from the wing tip: 380mm
Inboard end of the aileron: 370mm
Wing tip: 208mm

Unfortunately, these locations are not included in the service
letters
from=
LTB Lindner.

The tapes do not significantly improve the performance - perhaps
1 or 2
poi=
nts, you won't notice that. But they remove the seperation bubble
from the
=
ailerons and improve the airflow there. You will notice that the
glider
bec=
omes more stable in a turn. You will also need less aileron input for
corre=
ctions and the aileron in general is a bit more responsive.

Best
Christoph


Christoph,

Please re-read Lindner SL-12. It plainly states that all control
surface seals including the rudder may have the Z-Tape installed
just in front of the gap seals. In the case of the rudder, IMO, it
greatly increases the effectiveness of that control surface,
especially at low speeds like on initial take-off roll, etc.. The
drawings you refer to may be for possible increased performance
due to dealing with the laminar separation bubble where the
Z-tape is extended beyond the ends of the ailerons, but it is not
the same as where the service letter basically allows all Grob
glider types to have sealed control surfaces with optional Z-Tape
included.

RO