Ralph Jones (UK Schempp-Hirth agent and father of 3 World Gold
Medal glider pilots) fitted a water shift system controlled by
microswitches on the flap drive on one of his Nimbus 2s he owned.
On one Nationals flight the electrics failed resulting in a CofG aft of
the aft limit, making it almost uncontrollable in pitch, and an early
landout. Quickly modified to fit an emergency water dump to the
aft ballast bag.

Before EASA, you could do that sort of thing....

At 05:10 15 December 2019, JS wrote:
On Saturday, December 14, 2019 at 8:57:57 PM UTC-8, Duster
wrote:
A friend has installed a system in his home-built glider that
enables
shi=
fting the CG position forward during higher cruise speeds (e.g.,
between
li=
ft, final glide, etc.). It uses two water reservoirs whose content can
be
t=
ransferred using a 12v pump. This is done, ostensibly, to reduce
elevator-i=
nduced drag. Does anyone know of other gliders outfitted similarly
and is
t=
here a demonstrated utility?

There was one prototype Schweizer with a trolley that could be
cranked
forw=
ard/aft.
Dick Brandt's Nimbus 3 had a Mercury weight shift ststem for a
while.
Belie=
ve George Moffatt wrote about it in Winning 2.
Jim