In the 1960s, the B-52 bomber could navigate by the stars.

gnarf@hachyderm.io

@richrants @kenshirriff I was involved in the development of a star tracker for a satellite: It's basically a camera, a database of all the known stars and some fancy algorithms. You point it at an arbitrary bit of the sky and it gives you you're attitude relative to the rest of the universe, no other external inputs necessary except for the starlight

seachanged@mastodon.social

@vk2bea @kenshirriff

I doubted that 10 megaton yield, but indeed, the B-53 had a 9 megaton yield.

It replaced the B-41, a 25 megaton yield device.

kynx@fosstodon.org

@kenshirriff @dnaunton this is fascinating. I also congratulate you on one of the clearest summaries of celestial navigation I have read.

Ages ago I read Francis Chichester’s account of his solo float plane flight from New Zealand to Australia in the 1930s, when he pioneered aerial celestial nav. He went into some detail and was undoubtably a kind of genius, but completely incomprehensible! The man was not a writer. Or much of a mechanic… and that almost killed him.

mikesiegel@infosec.exchange

@kenshirriff I was wondering if satellite constellations fucks this up? I think these are still in use and given a dooms day scenario, it's likely anti-SAT weapons will be used and GPS may be jammed or useless.

liquid@infosec.exchange

@kenshirriff i read this as Apple Computer somehow

mike805@noc.social

@kenshirriff That's quite a piece of mechanical engineering. Aircraft machinery is wildly complicated.

The B-58 Hustler had the first digital navigation computer on a plane. They came up with a clever low-resource trig function algorithm called CORDIC. This was later used in the first pocket scientific calculators.

The SR-71 system was informally called R2-D2. That document says it required an air conditioning trailer on the ground.

mike805@noc.social

@kenshirriff Another example: how did they get 400 Hz AC power from a variable RPM jet engine?

If you connect a variable displacement hydraulic pump to a hydraulic motor, you get a continuously variable drive, but an inefficient one.

So they attached that to a differential gear. At cruise the engine speed matches the required generator speed. At idle the hydraulic drive makes up the RPM. At takeoff power, the hydraulic machine runs backward to subtract RPM.

Now that is real engineering.