On Tue, 21 Oct 2003 12:03:05 GMT, "Doug \"Woody\" and Erin Beal"
wrote:

On 10/20/03 9:42 PM, in article ,
"Mary Shafer" wrote:

Essentially, the SR-71 climbs at constant qbar (400 KEAS) to Mach 0.9,
then descends at a constant rate to Mach 1.25 (450 KEAS at 30,000
feet), and then climbs again at a different constant qbar (450 KEAS)
to cruise.

Thanks for the detailed response. Must come with the retirement.

I thinned the list of newsgroups down so I have a little more time to
type. And I'm a very fast typist.

I'm
interested in the 450 KEAS limit and the "Do not use excessive load factors
to prevent exceeding..." comment. What is an excessive load factor in this
flight regime. 1.5G? 2.0G?

Definitely in that vicinity. Let's see, section 4, probably. Limit
Load Factor Diagram, Symmetrical, Turning, and Rolling Flight,
Transonic Penetration (climb or descent). Symmetrical is 2.0 g up to
Mach 1.80 and rolling is 1.6 g. The absolute most you can pull is 3.5
g symmetrically or 2.8 g rolling, below 50,000 ft, at airspeeds
between 310 and 450 KEAS, at a gross weight of 80,000 to 90,000 lb.
It's less above and below those weights.

And the maximum design qbar works out to 500 KEAS, but the limit
airspeed is 450 KEAS.

The Ritowski climb is essentially the same thing. I think that the numbers
are different for most aircraft, but for the Hornet, it's 400KCAS to .85 in
the mid 30's, push it over to exceed 1.0, and climb supersonic afterward.
Works great on FCF's for the mil lock-up procedure (above 1.23M).

I just didn't know it had a name. I remember this from the optimal
trajectory work done in the '60s, in fact.

Someone has posted the URL for the SR-71 Dash-1, by the way. That was
made from the exact same copy that Dryden copied all of its from, as
it's probably the only formally declassified and marked copy
around--the thing is four inches thick and there wasn't any point in
going through and marking out the classification stamps in more than
one copy, because it's just too much work.

Mary

--
Mary Shafer Retired aerospace research engineer