Let's hear it for math! ('maths' for some of you outside
the US).

9B

Here's what I posted earlier in this topic:

Let's define the problem a little better - a pull up
from 100KIAS to
50 KIAS, level flight in both cases.
Pull to a flight trajectory of 30 degrees up relative
to the horizon.
This gives a vertical velocity of 50 knots immediately
after the
pullup. That 50 knots requires an extra 1 g for about
about 2.5
seconds(some simplification and approximation here)or
a suitable other
combination of G load and time). At the high speed
the extra induced
drag is quite small for a short time so can be neglected
to a first
approximation. The pullup will take only a few seconds,10
so that
difference in height gain is the difference in ballasted
and
unballasted sink rates for a few seconds. At the low
end the sink rate
difference is very small and at the high end the ballasted
glider has
lower sink rate. This difference might be as high as
200 feet/min but
we are only talking for a small fraction of a minute
so we get maybe
30 feet difference in favour of the heavy glider, maybe
only 10 to 15
feet.

Please note in the kinetic/potential energy equation
the mass cancels
out so to a really rough first approximation neglecting
the effect of
ballast on the polar the height gain is the same.


It's nice when the experimental results match the theory.

Note that all you are seeing in your flight test is
the difference
between the polars of two nearly identical gliders
with different
ballast loads at high speeds. (faster than best L/D)
The pull up/pushover manoevering is largely irrelevant.

Mike Borgelt