I almost skipped the videos embedded in this article, but they are well curated gems. A few tidbits I found amazing:
- 800°F (and above) was the temperature of their cooling air
- the engine ran too hot for electronics, so they designed a hydraulic mechanical computer responsible for regulating various inputs
- the roar from the two external 400 cubic inch Buick V8 engines originally used to start the aircraft was so irresistible to the hotrod enthusiasts running them that they sometimes neglected to disconnect in time before the starter engines overran RPM limits and "puked their guts out under the airplane" - they had to buy up so much replacement stock as to deplete every single junkyard across the USA of that particular model (so the story goes - probably hyperbole but a fun tale!)
> the engine ran too hot for electronics, so they designed a hydraulic mechanical computer responsible for regulating various inputs
There was a proposal at one point for NASA to deploy a 21st-century automaton to Venus because the atmosphere is too corrosive for an electronic computer. Supposedly it would have delivered its data to an orbiter using a balloon and then the orbiter transmits the information over radio. I really wish they'd do that, I would love to see what could be done with mechanical computing using modern technologies.
Unfortunately there aren't a whole lot of situations where clockwork logic makes more sense than semiconductors.
I remember quite well the day the auctioned off a unique "jet fuel analyzer" that was used to do some of the specialized testing for these exact aircraft.
It was not a benchtop unit, it was a forklift model :\
For those that want to know more about the Buick engines and their replacement, here's [0] a writeup about it.
[0] https://www.thesr71blackbird.com/Aircraft/Engines/starting-t...