On Sun, 12 Apr 2015 19:55:55 -0700, Jonathan St. Cloud wrote:

The SR-71 did have an what was refer to as an"unstart" where usually
just one engine would flame out. This aircraft was one of the most
amazing aircraft ever designed and built. it was the first stealth
aircraft. A great read is "Sled Driver"

Unstarts are nothing to do with flame-outs. In an unstart the shockwave
from the spike pops out of the intake (during normal operation it is
captured by the intake) but the J-57 continues to run. There is a loud
bang accompanied by violent yaw and strong deceleration, mainly because
80% of the thrust comes from the ram effect and reheating the bypass
flow. When an engine unstarted most of this thrust component vanished.

"Flame out" meant that the J-57 had flamed out like any other jet engine
can do: once that happened it wouldn't restart above 30,000 ft: you just
wasted a shot of TEB if you tried a higher start.

This info comes from "The Complete Illustrated History of The Blackbird"
by Col.Richard H Graham and from hearing Col. Graham's talk. If you want
to know more about the SR-71 this is an excellent book to get.


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