It will gain more height with ballast. The
kinetic energy is defined as 1/2*m*v squared.
[...]
The potential energy is m*g*h,
[...]
So for example, if a gldier weighs twice as much, it will
gain twice the height, or at least I think so!

Again, take out the constants. Both aircraft have the same velocity at the
beginning, 100Kts. Assume, for the sake of argument, that they have the same
velocity at the end, say 30 kts (I know the heavier one will stall first, but
in a vertical pull up, the wing loading is zero, so the stall speed would be
very close).

SO at the beginning, the delta in kinetic energy for two ships travelling the
same speed is only proportional to the mass. Since the heavier one weighs more,
it has more kinetic energy. At the end of the pull up, when all the kinetic
is converted to potential, take out the constants again (g), and the only
remaining variable is h. h is proportionally more for the heavier ship. And,
as I said before, this is not accounting for drag.

P.S. I f'in hate calcusus. R dR d theta double dot!
Jim Vincent
CFIG
N483SZ