"J.A.M." wrote in message
...
IIRC the F-4 experienced an increase of the actual G-loading when
manouevering through the Mach 1. If you were pulling close to the
structural
limit you could have an overstress problem. Aerodinamics thing,
displacement
of the center of pressure, that kind of thing. Maybe a Phantom driver
could
explain it better.

The aerodynamic center shifted forward abruptly as you were decelerating
through about .95 IMN. As the aero center shifts forward, the stabs
downward trim force becomes greater and a pitch up occurs. (This is rather
typical transonic behavior, although it varies from jet to jet.)

In the F-4's case, if you were pulling 6 G or so, you'd suddenly find
yourself around 9 G during this transient. At medium/high altitudes, the
airframe would give a hint that this was about to happen with a subtle
buffet cue. You could reduce your back stick just as the aircraft dug in
and maintain your G without exceeding it. If you were low (say 5,000',
higher IAS for .95) the buffet cue wasn't there and it could sneak up on
you.

I experienced the low altitude manifestation once and use the incident as an
illustration of the effects (big time overstress) of transonic pitch up for
my aero lecture.

R / John