Here is a slice from the excellent Hermeus Podcast, with former Air Force pilot and general Robert Behler. He flew the SR-71 Blackbird, and provides his perspective on the five major innovations that allowed the aircraft to achieve incredible speeds and performance:
The first one was physiology. How do you keep the crew member alive at those extreme altitudes, temperatures, and speeds to be able to eject at 80,000 feet at Mach 3 and survive, which we could and we did.
Number two would have been the whole ramjet to build the right kind of propulsion system. It hadn’t been done before. That’s where the magic was. Ben Rich designed those inlet ramjet and it and it was just an amazing amount of genius
Number three of course the aerodynamics. The SR is a double delta wing, and that was not by accident. When you go transonic in the SR, the aerodynamic center moves aft very quickly up to about 45 to 50 percent and meet at another chord which causes a lot of loss of dynamic stability. So chines went out there that moved it forward. When you got the speed in altitude, the CG [center of gravity] started moving aft and the aerodynamic center started moving forward and they met at 25 degrees mean aerodynamic chord which meant there was basically no trim drag that allowed the airplane to fly that fast. That was another one of those remarkable things.
Number four was material science — how do you keep that airplane from burning up going that fast. The average temperature was over 600 degrees and the cockpit was 622 degrees and I was right behind this little window. So the material science is how do you use titanium how do you mill it and all that had to be done from zero knowledge base. The windows were you know like three or five inches thick and from the sensor standpoint the lenses on the cameras had to be preheated hours before the flight because of the thermal distortion that would occur as you fly faster.
Then the fifth thing was an innovation that had to be developed, the astro-inertial system. We didn’t have GPS. We had to be able to fly anywhere in the world and be able to stay on the black line. The system was an astro inertial system that looked at three stars simultaneously and updated the inertial navigation system. I’ve had missions where I’d fly from California over the top of the pole into Mildenhall [Britain], we’d look at the ins and it’s maybe a couple meters off. That’s how good it was.
Listen to the whole thing!
Imagine if the Lockheed team had to do all of today’s documentation for the SR-71. It is difficult to imagine the program succeeding for less than $1 billion per unit, if it could succeed at all.
Behler said that there were a thousand inventions that had to occur. The five listed above would have sent GAO into shock. GAO always cites “knowledge” and technical maturity as the most important aspect of successful programs. They point to programs like the DDG-1000 as far too risky and a failure as a result. But the KC-46 largely failed despite having very little to develop.
I think something else is going on entirely. I think there’s some combination of inarticulate knowledge — a “vision” or “anticipation” of what is likely to work — and plain old trial-and-error engineering to overcome the myriad challenges that pop up. It’s hard to separate that from the genius, grit, and perseverance of the individuals involved. It’s hard for outsiders to select which plan and team will work. Otherwise, either startups wouldn’t exist or venture capital would look very different.
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