In article ,
(Kirk Stant) wrote:

| Kevin Neave k wrote in
| message ...
| The difference in height will be negligible.
|
| Not true. A full load of water makes a HUGE difference in pullup
| altitude gained
|
| The glider's energy, both potential & kinetic is proportional
| to Mass so the height gain for a given loss of velocity
| will be the same.
|
| Again, wrong - check your basic physics. You even say that the energy
| is proportional to mass. Therefore, more mass, more energy, more
| altitude gained. You appear to be confusing velocity with mass.

Total energy = kinetic energy + potential energy

kinetic energy = 1/2 mass * velocity squared

potential energy = mass * gravitational constant * height

total energy (altitude 1) = total energy (altitude 2) [conservation of
energy]

Since mass is a constant factor on both sides of the equation, it
cancels out. Therefore there should theoretically be negligible
difference in the pullup altitude gained between the ballasted and
unballasted cases.

-- Tim Olson