The numbers I have seen is that the SR-71 had a max. weight
of 78,000Kg (in flight) but a max. take off weight of only
56,000Kg. And even at that weight they were rotating at
235 knots.

Regarding leaks, the SR-71's tanks leaked like a sieve on
the ground, but sealed up tight as soon as they got up to
speed and the wings heated up.

Lockheed never came up with a sealant for the tanks that
would tolerate the heat loading AND the 8" expansion of
the airframe in flight.

Big John wrote:
Jay B

Story I always heard was that they took off with a light load of fuel
due to either W & B or structural limits and tanked shortly after
take off for the initial phase of mission where they might be required
to tank several times.

Leaks yes.

Big John
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`
On Mon, 13 Dec 2004 22:43:23 -0700, "Jay Beckman"
wrote:


"Jay Honeck" wrote in message
news:ektvd.189728$V41.138784@attbi_s52...

Hehehe...cool.

Thanks!

Other cool tidbits from Bill:


Security. At Lockheed's Burbank, CA facility, they were testing the
SR-71's fuel tank and the explosive nature of the special fuel the
Blackbird used. They drained a tank, leaving fumes in it, and heated it
to hundreds of degrees, to simulate in-flight conditions. It, of course,
exploded, blowing the building to bits and starting a raging fire.


Hey Jay,

Double check something else with Bill if you still have him available...

JP-12:

So, they fill the SR-71 on the ground and it would leak like a sieve until
it got up to altitude and expansion of the airframe "sealed" the leaks
(necessitating an immediate tanker join once airborne...)

So here's the kicker, I recall reading that you could make a torch out of a
T-Shirt on a stick, light it, dunk it in a bucket of JP-12 and the JP-12
would do nothing but extinguish your torch...JP-12 was anything BUT
explosive and it required immense pressures to get it to ignite (fumes, of
course, are a different kettle of fish.)

Jay B