This inflection point between analog and digital computer is a fascinating one. At one point in time a analog computer made sense and some later point in time you would be foolish to specify anything other than a digital computer. But that time between when it could go either way is interesting. There is a good autobiography by the person responsible for introducing the first digital computer to the navy that provides an interesting view into this era. https://ethw.org/First-Hand:No_Damned_Computer_is_Going_to_T...
Now I am vaguely searching for a guide on gear train schematic diagrams, I am sure they had them, you don't reason out something this complicated without one. I know hydraulics has it's own flavor of schematic diagram, which are fascinating if all you have seen are electronic circuits. https://www.hidraoil.com/technical-resources/hydraulic-symbo...
That is the best title for a story about replacing analog and mechanical instruments with digital computers. A similar process is happening now with natural intelligence, replacing or augmenting the human intellect.
An interesting resource I just found:
The analog computer museum - https://www.analogmuseum.org/english/
It has a Library section with lots of downloadable articles in German and English.
I've seen the restored guidance computer for the Nike missile, at the site in Marin County.[2] That's similar, although ground-based. Analog data came in from radars, was processed with mechanical computation, and control signals went out to the missile.
[1] https://en.wikipedia.org/wiki/Admiralty_Fire_Control_Table
Also the Battleship New Jersey YouTube channel has some nice content on this: https://www.youtube.com/watch?v=szxNJydEqOs
Excellent illustrations!
Was also a Nike base on Angel Island but there's nothing left there but some old concrete pads.
We actually had one of the Nike bases defending Philadelphia literally next to where I grew up. Don't remember personally--was very young--but there were apparently troop manoeuvres on our property from time to time.
We may see large numbers of local defense sites again, against drones and medium-range missiles. Israel and Iraq already have that.
And here I am fighting gitlab pipelines.
One life to experience the universe. Save up for a sabbatical. Find new engineering pastures.
It's always rose colored looking back. Not everybody got to work on this. Some people were storming the beaches...
And other people, like Henry Kissinger, drew random dots on a map to tell it where to drop the bombs. https://en.wikipedia.org/wiki/Operation_Menu
To make it ABUNDANTLY CLEAR, I was referring to celestial navigation.
I guess we have to blame people who weren't alive at the time for wars we didn't participate in?
My wife is Vietnamese, btw.
The end game of much of silicon valley seems to be government (read: military) contracts. Probably because its the main branch of government that's thoroughly funded
Don't get me started on that...
> The Astro Compass needed to know approximately where in the sky to find the star, in order to point its sensor in the right direction. The direction didn't need to be exact because the Astro Compass performed a spiral search pattern to find the star. This search pattern covered ±4° in bearing and ±2.5° in altitude. In comparison, the Moon is 0.5° wide, so it's a fairly large target area. ↩
Why would the system need to have a much greater range of declination (celestial sphere) than latitude (Earth spheroid)? Because the Astro Tracker and Angle Computer could flip over to the Southern hemisphere (was this automatic or was there a switch?) having that much declination range seems unnecessary. Perhaps to allow for pitch of the aircraft in flight?
BTW, being able to operate in both the Northern & Southern hemispheres was an important capability for the B-52. Previous bombers (B-36 mostly) had the range but not the reliability or in-flight refueling for global reach.
Sadly, I didn't get the chance to look at the B-52 at the Museum of Flight when I was there. If you ever meet Charles Simonyi, please thank him for his support of the museum.
Or is it that they considered the need to navigate below the lower fourth of Argentina a distant possibility?
How did it determine "down" in a moving airplane? Was it essentially doing the high-tech equivalent of dangling a rock on a string with some dampening (in a gyroscopic cage to avoid being affected by the airplane's rotation), or something smarter?
When I looked into whether astronavigation would be solvable cheaply or somehow trivially using modern hardware, I found this a surprisingly difficult problem even on a static platform - inclinometers that would get you down to 0.01° accuracy (which would still translate to a ~1 km positional error if I'm not mistaken, roughly what a skilled sailor is supposed to be able to do with a sextant) are expensive even today.
With a moving, shaking platform that's changing position (i.e. a perfect gyro will point perfectly in the wrong direction after a few minutes of flight) and might be flying turns (which makes "down" point in the wrong direction) that seems hard to solve.
Yes, that is essentially how a gyroscopic artificial horizon works.
Consider that the local horizon changes relative to an inertial frame (the stars) as you travel across the surface of a sphere, so even if you could build a perfect gyro that remained stationary in the inertial frame you would need to update the local down as you move. The solution is to slightly weight the gyro cage to bias it to the local down.
Now, consider that, in a properly-coordinated turn, the passengers (and gyro) will feel that gravity points straight to the floor :) So the time-constant of the damping is important.
Still, getting this whole thing accurate to probably one minute of arc is insane, especially with the gyro and star tracker linked only via motors and synchros. So the total error is the sum of any deviation of the gyroscope from the actual down direction, the error in measuring the gyro angle, the error in setting the star tracker to that exact angle, and then all other errors the system introduces. Then you need to take multiple separate measurements at different times and compensate for the movement, and a one-degree difference means you're over the wrong city (or in Europe, country) so the end-to-end accuracy must be much better than that.
And sailors supposedly did that with a sextant to something like 0.01° on a moving ship.
Really curious how they did this mechanically.
can i do something with a v1 raspberry pi and myriad idle laptops and gadgets. both Opus 4.7 and i have had enough of each other for a Caturday
Auto manufacturers should take a clue here.
https://aviation.stackexchange.com/questions/22680/why-is-th...
Humans fascinate me sometimes.
https://assets.publishing.service.gov.uk/media/578defbae5274...
https://assets.publishing.service.gov.uk/media/578def27ed915...
(Two separate incidents in the same year, on the same day, even)
EDIT: Updated links to point to incident reports
Meta, but thank you for including this and suggest even putting it at the top of your articles. I'm now off to bother to read something that someone bothered to write :)
I think it provides ground track information not just heading? Which is far more valuable for aircraft navigation, because the main issue is unpredictable wind drift.
> The diagram below shows the guidance system of the Minuteman III missile (1970). This guidance system contains over 17,000 electronic and mechanical parts, costing $510,000 (about $4.5 million in current dollars). The heart of the guidance system is the gyro stabilized platform, which uses gyroscopes and accelerometers to measure the missile's orientation and acceleration.
The 8-bit Guy recently released a video asking "What if everything still ran out vacuum tubes?" <https://www.youtube.com/watch?v=mEpnRM97ACQ>. Conclusion: A surprising amount of things we take for granted today would still be possible.
[0] https://en.wikipedia.org/wiki/Antikythera_mechanism
[1] https://apps.apple.com/app/id989574753
The angle computers were removed from the H models in the early to mid 1990s and I doubt they added them back.
https://arstechnica.com/information-technology/2020/05/gears...
