Aft CG limit(s)

Recent threads that discussed handling and performance have referred
to the aft cg limit, perhaps implying that there is a fixed aft limit.

For the ASW-19b and the ASW-28, the gliders I have most recent
experience in, the aft cg limit moves forward as the gross weight
increases. I assume this is true for other glider types but I don't
have data available.

For the ASW-28 the manufacturer recommends an optimum cg range of
300-310mm aft of datum but does not seem to mention that the aft limit
of this "optimum" range is behind the aft cg limit at max gross
weight.

I have found that a cg position of 320mm aft of datum gives best climb
performance at 9psf loading without compromising the high speed
performance. That cg is at the aft limit for 9psf but well forward of
the 345mm "dry" aft limit. (9 pounds per square foot is a loading
limit for USA standard class contests)

The low weight cg range for the 28 is 227-345mm aft of datum for those
that want to consider percentages.

So how many of you know if the glider you fly has a weight dependent
aft cg limit?

Andy (GY)