That's exactly right Bertie. I never ran into anyone who knew that except
for a few engineers at Boeing. I'd love to meet you sometime. I was
fortunate enough to be able to take all the aero engineering courses they
offered. It was great. Most of the instructors were old 707 engineers. I
had great respect for them. They had all kinds of rules of thumb that I
never hear about. I have a note book full of them. I don't even see
reference to them in the the my bible, the NAVWEPS.

--
BobF.
"Bertie the Bunyip" wrote in message
...
"Bob F." wrote in
:

WrongO againO. The "coffin corner" is an altitude (point on a chart
where the stall speed and Mach come together) with a max power
setting. If you go faster, you get mach buffet. If you go to slow,
you stall. If you reduce power setting, you stall. If you nose over
to recover, you mach buffet. With your example I can see why you're
confused.


Acctually, the low side buffet isn't strictly a stall. The proof of this
is
it happens at a much higher indicated and much lower alpha than a stall at
low altitudes. The wing doe lose lift, so in the broadest definition of a
a
stall the wing stals, but what's actualy happening is that the increased
angle of attack you neccesarily have as you reduce speed increases the
speed of the air over the wing so that there are localised areas of
supersonic flow with an accompanying buffet. So what coffin corner
actually
is is an onset of mach buffet caused by any combination of speed and
alpha.


Bertie