Chad Irby wrote in message ...
In article ,
(frank wight) wrote:

There was a time when I thought that
the blackbird could secretly hit 5 on the
mach meter--but isn't there solid science
agains this? Such as:

I don't think the engines have the ability
to rev up to such a speed. Maybe the jet fuel
itself cannot produce sufficent BTU's (thrust)
to propel it that fast, maybe the fuel lines
are too small to exceed Mach 3.3

Perhaps the real inhibitor is the lack of
enough combustible oxygen to feed the engines
to shatter established speed records.

I know that the outer metal shell of the
jet couldn't sustain the high atmospheric
friction.

Am I right about all this, or is there OTHER
things to consider?

A lot of that is pretty much on the mark. I've heard Mach 3.5 for short
sprints, but not more than 3.3 for sustained flight.

Mach 5? No way in hell, although I've seen a very few claims for Mach 4
sprints (extremely informally on that one). Even if they could manage
the power to do it, the skin would be melting (see the thread on the
Sanger Amerika Bomber for some of the problems with sustained very high
speed flight).

Same here. I live in northern California so I have heard all the stuff
coming from Beale AFB and the Mach 3.0-3.5 range seems to be the
truth; however, the airframe of the SR-71 is stressed for Mach 4.0
flight. Maybe like the Foxbat this was for emergency only with
resulting damage to the engines and a/c. But I see little need for
such speed given the Blackbird's height invunerability.

Rob