"G.R. Patterson III" wrote in message
...
Seems to me that you have listed most of the effects correctly. One thing
you
should consider, however, is the fact that the balance envelope for most
(if
not all) planes gets narrower at the top.

A true generalization as far as I know, but I'm sure there are a number of
exceptions and in many cases, the shape of the W&B envelope has as much to
do with what test parameters the manufacturer chose to look at, as it does
any real structural or aerodynamic issues.

The main thing is to make sure one is paying attention to the W&B envelope.
When flying overweight (with FAA approval, of course) one can make an
educated guess by extrapolating the existing graph, but the bottom line is
you don't really know what the shape of the W&B envelope is over gross,
unless the manufacturer has been kind enough to publish it (and they usually
aren't).

In other words, the more weight you
put in an aircraft, the closer to the center of lift that weight has to
be.

Not really. In some aircraft, the envelope is sloped on the aft portion too
as weight goes up. For rearward CG configurations, additional weight needs
to be put farther from the center of lift, not closer. All you can say
without seeing the actual W&B envelope is that usually you have a narrower
range at higher weights. You can't say which direction that range trends,
and even that generalization has exceptions.

[...] At some point, all of the weight will have to be in the front seat.

Even if the previous statement were true, not all airplanes have their
center of lift aligned with the front seat.

I have read of cross-Atlantic ferry flights in which the aircraft was
loaded to
weigh about 1.6 times the normal MGW. In one account, a Bonanza loaded
that way
took over 6,000' to get airborne.

How much runway did Voyager take? I'll bet it was a LOT.

Pete