I just tried this - but had to use a pair of bicycles.

Me (unballasted) and my boss (ballasted) on similar
bikes
at the same speed coasted up a small hill. He was going
significantly faster at the top.

Happens every lunch time so must be true.

At 13:30 08 September 2003, Szd41a wrote:
A given glider is at level flight, IAS= 100 knots.After
a pull-up, will it
achieve more height gain with 100 liters (100 kgs)
of ballast than with
empty ballast????
Réjean