Hi Todd
This debate is pointless, some say. By looking at the numbers of visit, it
is of a certain interest to many people!!! I set fire on a european forum
too, the debate was hot, but quickly ended with a tie, or nothing measurable
from the cockpit. This debate allowed me to review some flight theory, and I
think it is beneficial to anybody who participate to this. Drag is something
that is anything but intuitive, and has to be looked at closely, actually
kinetic energy is far from intuitive, too(but easy to calculate), and many
had to review their opinion when they did the simple maths.

I read your comment here;

"Not true. The heavy glider pays for the higher drag with
less altitude lost, just like it pays for the higher drag in
1G flight with less altitude loss. That's why we carry
ballast. This is an advantage for the heavy glider here"

and I would like your comment. The reason we carry ballast is not is not
quite that drag-altitude trade, but because when we are ballasted, the
component of weight parralell to the direction of flight is bigger (Bigger
engine) For a given AOA, you will go faster ballasted. Drag is not running
the show, it will be a consequence of the flight attitude. Weight is the
motor. The polar curve reflect the situation as long as you are gliding,
that is going towards Mother Earth, weight helping you along. Your wings
will create enough lift to equilibrate weight. It is so well designed that
it will generate lift at the same best L/D even with a bigger loading ( and
perhaps an even better L/D..but not much!!!!) Now, generaly speaking in
aircrafts, lift does that and only that. If you want to gain height, you
throttle up or you crank that thermal, not counting on lift per say. Maybe
we are all saying the same thing, it is just what comes first the egg or the
hen????

And then, following your reasonning...

Your assumptions are unconvincing to me. We can show by
simple analysis that the heavy glider is always losing less
altitude per second, at least until it gets down to its best
L/D at the current load factor. The largest rate of
altitude loss will be at the beginning- high speed and high
load factor.

Now, I think that as soon as your nose is pointing up, the polar does not
reflect the flight characteristics anymore. Why?? Maybe because weight is no
more the motor . It has no component in the direction of flight. It has
become a load that you have to carry. I am not too sure we can say we are
loosing less altitude for a given speed, and conclude that it will go
higher. The polar does not apply to this part flight. What is the motor
then?? Kinetic energy of course and we are going ballistic. Lift can even be
a nuisance pulling you away from optimal path. If we are uniformely
accelarated, speed decrease will be 9.8m/s/s for both glider.


Does this sound right??