At 18:35 23 August 2018, wrote:
I fly unflapped standard ships.
I used to fly a DG300 mainly dry. Tow in 110km/h range is not a
problem.
This year I switch to a Discus 2. It has a big AoA also when on the
ground
=
and
it need about 130km/h dry to have and more speed when it is wet.

Both ship dry has the same weight and the almost the same
surface. I think
=
the main factor is the AoA. The differences are in the AoA and also
in the
=
tow hook position (baricentral for DG300 and on the nose for
Discus 2) who
=
main influence the stability on tow. When on tow we fly at relative
low
spe=
ed at high AoA fly in an uncommon attitude for the glider.

I always say my load and the desired speed at tow pilot befor take
off.
ciao,
giovanni



The D-2 has an Angle Of Incidence (AOI) that corresponds to that of
flapped wing gliders. It came from 15m owners wanting to fly STD
Class competitions, and being allowed to do so with their flaps
locked at the zero setting. It was assumed that these 15 m birds
would be at a disadvantage in the climb because their airfoils were
not optimized to always be at the zero flap setting. It turned out
that the 15 m gliders did quite well in the STD Class, and were
noticeably better in the higher speed regimes due to their lower AOI
causing less (fuselage) drag. Centrair was the first to exploit this
with their Pegase, which is basically a "no flap" ASW-20. Anyway,
the D-2 has this lower AOI, so the visual sight picture from the
cockpit is somewhat more "nose high" at slower speeds than on
previous generation STD Class birds. It will fly just fine down into
the high 30 Kt range, but if you are on tow, the nose is so high by
then that you will have trouble seeing the tow plane. Take it from a
19 year D-2 owner. If the tow gets a little slow for your comfort,
just offset your tow position to the left side a bit. Then you will be
able to see the tow plane in the front right side of the canopy, AND
the tow pilot will thank you for doing it so that he/she doesn't have
to stand on the right rudder pedal so much...

RO