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From: ron@nbife.NBI.COM (Ron Schweikert)
Newsgroups: rec.aviation,sci.space.shuttle
Subject: Re: SR71 to be retired October 1st, rumors regarding SR-71
Message-ID: <989@nbife.NBI.COM>
Date: 20 Mar 89 15:09:13 GMT
References: <524@gonzo.UUCP> <1475@petsd.UUCP> <13987@elroy.Jpl.Nasa.Gov> <281@cbnewsl.ATT.COM>
Organization: NBI Inc., Headquarters Service Centers
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In article <281@cbnewsl.ATT.COM>, sw@cbnewsl.ATT.COM (Stuart Warmink) writes:
> In article <5983@homxc.ATT.COM> h16@homxc.ATT.COM (D.JACOBOWITZ) writes:
> >I think the reason for taking off light on fuel (50-60% capacity,
> >I thought), was to increase the safety margin in case of engine
> >failure during takeoff.

Structural reasons only.  Like many aircraft, it can't land with it's max
fuel load.  Also, it took off only with enough to hit the tanker.  No need
for more for majority of missions.

> 
> Talking about engine failure, if this happens during a high-Mach run, the 
> resulting asymmetrical drag yaws the aircraft around so fast that the crew's
> heads (or rather, their helmets!) are banged against the cockpit's windows.
> [The engines can flame out at supersonic speeds if the inlet shock-cones are 
> not set to the correct position for that particular speed...]
> 
> (I read about the above many years ago in some aviation magazine.)
> -- 

The banging of heads is true, even saw a cracked helmet.
As far as the 'flame out' causing that, it wasn't a true flameout, although
those did happen and would cause same symptoms.  Most of these asymetrical
gyrations were caused by 'unstarts', where for some reason or another, usually
though by the computers that control the spike, the inlet lost control of
the shock wave.  The J-58 was not a supersonic engine, besides a majority
of the thrust was caused by bypassing the shockwave around the engine and
redirecting into the afterburner section, so loss of the shock wave effectively
'flamed out' that engine for the purposes of thrust.  When this happened, 
the spike would go to full forward position, then the computer would 
retract it to proper position for shock wave control.

BTW, let me make a brief comment on one poster's conern about military
secrets.  Everything that I've posted, or seen posted that was correct, is
public knowledge.  Maybe not wide public knowledge, but public nevertheless.
Certainly there are things that are not to be discussed, but as for my part
as I said before, I haven't read anything on the net that couldn't be found
in Janes, Aviation Leak or Air Progress in some issue or another.

Your point however is well taken.  Rest assured...

By the way, talked to an old SR buddy last night.  He'll let me know when
he hears of any retirement ceremonies at Beale.  I'll post when I hear.

Ron Schweikert