Blue Streak

On Mon, 21 Feb 2005 17:06:01 GMT, (Henry Spencer)
wrote:

(as best I can sort it out with references on hand -- I'm busy
and don't want to do a real digging job on this one)

....Oh dear. Henry provides evidence that he's actually *mortal*!

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

"OM" om@our_blessed_lady_mary_of_the_holy_NASA_researc h_facility.org wrote
in message ...
On Mon, 21 Feb 2005 17:06:01 GMT, (Henry Spencer)
wrote:

(as best I can sort it out with references on hand -- I'm busy
and don't want to do a real digging job on this one)

...Oh dear. Henry provides evidence that he's actually *mortal*!

No, it just means that the multi-processor AI system that actually is "Henry
Spencer" has been partitioned for maintenance, and the side running the
application has less resources than normal. It's one of the canned messages
stored in the system, along with the complete details of every Apollo
mission and the smug Canadian superiority.

-
Jim
Those of us with Univac 1100 series backgrounds can recognize the
interprocessor communications and partitioning...

In article , says...
Several sources agree that the long-term solution -- made possible by
faster engine controls -- was to automatically force the *other* engine to
unstart as well, so recovery proceeded simultaneously on both. Removing
the asymmetry made an unstart a much less traumatic event.

Oh wow! The mind boggles.

I'm so used to thinking about using redundancy to survive single-point
failures that I *never* *ever* would have realized that the solution to
a single engine failure was to deliberately fail the good engine.

I guess Kelley Johnson is a better engineer than me...
--
Kevin Willoughby lid

The loss of the American system of checks and balances
is more of a security danger than any terrorist risk.
-- Bruce Schneier

Kevin Willoughby wrote:

Oh wow! The mind boggles.

I'm so used to thinking about using redundancy to survive single-point
failures that I *never* *ever* would have realized that the solution to
a single engine failure was to deliberately fail the good engine.

I guess Kelley Johnson is a better engineer than me...



According to the pilot's manual, that's only done some of the time:
http://www.sr-71.org/blackbird/manual/3/3-33.htm

Pat

Am Mon, 21 Feb 2005 17:06:01 GMT schrieb "Henry Spencer":

Apparently it was (mostly) fixed when they went to digital controls, which
could respond more quickly.
The ones with the improved controls still got inlet unstarts. What was
different was that the automatic controls would immediately slap the
rudders over to compensate...

As I remember (having somewhen a year ago read Graham's "SR-71
revealed") even the improved controls did NO automatic input to the
_aerodynamic_ control surfaces at the occurence of an engine unstart...

The answer (as best I can sort it out with references on hand -- I'm busy
and don't want to do a real digging job on this one) seems to be "all of
the above".
Kelly Johnson's autobiography explicitly mentions the rudder kicker.
By the looks of it, that was an interim solution.

OK, I digged through a couple of books - Kelly Johnson's bio, Ben
Rich's bio, Graham's book (again) and some sources on the web. All
sources - except Kelly's - said, that RUDDER control during an unstart
was the pilot's job (and btw. hard work), only the automatic spike and
bypass door controls were soon enhanced to create a "sympathetic
unstart" of the other engine. That solution of automatically kicking
in 9 deg. of rudder input during a split second (mentioned by Kelly)
sounds like a very interim solution that did not last as the real
solution - especially in view of the fact, that NOT the yawing was
seen as really critical, but simultaneous pitch and yaw changes
instead were seen as much more critical (in the view of the fact, that
the blackbirds have a flat fuselage that causes a large part of
plane's total lift, so this sounds reasonable)...

I guess, that this interim solution was included into plane's
autopilot wiring (blackbirds had a very enhanced inertial navigation
system, that was not only able to detect changes in the plane's flight
path, but in its direction, too), so it could do its share of work
holding the plane straight on occurence of an unstart; maybe this was
meant when an automatic control of the aerodynamic control surfaces in
case of an engine unstart was mentioned. But that doesn't count -imho-
as special unstart related behaviour...

grin mode on I _/*WANT*/_ an ICH SHIRT :-) !!!1111111 /grin


cu, ZiLi aka HKZL (Heinrich Zinndorf-Linker)
--
"Abusus non tollit usum" - Latin: Abuse is no argument against proper use.

mailto: http://zili.de

Am Tue, 22 Feb 2005 23:34:37 +0100 schrieb "Heinrich Zinndorf-Linker
(zili@home)":

[...] that NOT the yawing was seen as really critical,
but simultaneous pitch and yaw changes instead [...]

please replace 'yaw' with 'roll'...

cu, ZiLi aka HKZL (Heinrich Zinndorf-Linker)
--
"Abusus non tollit usum" - Latin: Abuse is no argument against proper use.

mailto: http://zili.de

Heinrich Zinndorf-Linker (zili@home) wrote:

Am Mon, 21 Feb 2005 17:06:01 GMT schrieb "Henry Spencer":


OK, I digged through a couple of books - Kelly Johnson's bio, Ben
Rich's bio, Graham's book (again) and some sources on the web. All
sources - except Kelly's - said, that RUDDER control during an unstart
was the pilot's job (and btw. hard work), only the automatic spike and
bypass door controls were soon enhanced to create a "sympathetic
unstart" of the other engine.


And then in only some situations, if the fault is mechanical or in the
pressure sensors, unstarting the other motor isn't going to help
matters. The pilot is then instructed to manually restart the unstarted
motor while leaving the other one alone.
You know, I've listed this page twice now:
http://www.sr-71.org/blackbird/manual/3/3-33.htm
This is the section from the pilot's manual that talks about how
unstarts are dealt with, it gives extremely detailed info on the whole
process.

Pat

"Henry Spencer" wrote in message
...
(Well, faith in
British high technology, anyway -- American high technology was thought to
be capable of almost anything.)

"We build monster trucks for *fun*- **** us off and see what we build." -
Christopher Titus, The Tonight Show, early 2002.

In short, al-qaida and the Taliban's primary mistake was not that they
attacked the United States, but that they did it in a manner that not only
the elite and intellecuals understood, but that Joe "Sixpack" Taxpayer did
as well. Putting a hole in a destroyer halfway around the world causes a lot
of grumbling. Doing something that *someone I know and trust can see right
out their window* gets people to act.

In article ,
Pat Flannery writes:
That's not what happened- the outboard motor was shut down, and the
plane did crab to one side; then the inboard motor on the same side lost
thrust (I assume from being caught in the disturbed airflow off of the
nose) and the aircraft turned ninety degrees to the airflow and
immediately disintegrated.

Found in test engineer's notebook: "OK, let's not do that again."

On Fri, 18 Feb 2005 20:13:18 +1100, Malcolm Street
wrote:

My favourite was the way early Lockheed Blackbirds, with analog controls on
the shock cones, would get an "inlet unstart" when IIRC the cone couldn't
keep up with the movement of the shock wave and the latter collapsed.

It wasn't just the early Blackbirds, it was all the Blackbirds. The
digital controller was a retrofit long after the airplane became
operational.

And the digital system didn't prevent all unstarts. We were getting
unstarts in 1998, long after the USAF retired the airplanes. However,
the digital system worked better at throttling back the good engine,
thereby reducing the yawing considerably. This made the unstarts more
comfortable and easier to recover from.

Mary

--
Mary Shafer Retired aerospace research engineer