Mechanical Computer (All Parts) - Basic Mechanisms In Fire Control Computers on HackerTube: recommended by 13 Hacker News commenters across 12 separate months, 2014–2025.
documentary · intro · evergreen
A 1953 US Navy training film explaining the basic mechanisms in mechanical fire control computers aboard ships. It shows how gears, differentials and cams solved mathematical problems in permanent mechanical form.
HN commenters repeatedly recommend it as a beautiful, approachable explanation of analog mechanical computation, and many have rewatched it.
“It illustrates the problems and solutions near perfectly, and I've watched it way too many times.”
20 Hacker News comments link this video. Each one links back to its thread.
Everyone reading this right now needs to check out this 1950s naval training video on the mechanical fire control computers of battleships: ▶ this video For fun, before you watch, think for yourself how you'd implement addition, multiplication, squaring, etc. with only gears and other mechanisms.
in “Knocker uppers: Waking up the workers in industrial Britain (2016)” · View on HN
The whole training film on mechanical computers, for navy mechanics I believe: ▶ this video It illustrates the problems and solutions near perfectly, and I've watched it way too many times.
in “When mechanical analog computers ruled the waves (2014)” · View on HN
I did not see any link to the full training video[0] the clips in this article were taken from. I highly recommend it. It's a fascinating trip into engineering, computing, and the past. [0] ▶ this video
in “When mechanical analog computers ruled the waves (2014)” · View on HN
▶ this video This is an old military instructional video about fire (artillery) control computers, explaining the mechanical aspects of how they work. It's beautiful in its elegance! I have watched it on multiple occasions just for the sheer beauty of the mechanisms involved. And, yes, of course I'm a nerd!
in “The Turing Tumble lets you and your kids build real mechanical computers” · View on HN
I just smile hearing the term "Millihertz Computer". I'd love it if building and designing mechanical and analog computers grew as a hobby/educational activity as I find them both fascinating and somehow satisfying. Also, this 1950s Naval Training film explaining the fundamentals of how mechanical fire control computers work to solve complex problems is excellent. ▶ this video
in “Millihertz 5 Mechanical Computer (2022)” · View on HN
Yes, these are awesome. There is another one of these old films about them which is a great explainer: ▶ this video
in “Telegram for America (1956) [video]” · View on HN
If you’re interested in some of the individual components, there’s a great 1950’s US Navy training film on the individual components of analog fire control computers here: ▶ this video The ideas are the same, but the technology is about a decade earlier than the CADC, so everything is noticeably more primitive.
in “The Bendix Central Air Data Computer (CADC)” · View on HN
Mechanical computers for fire control where the standard solution until very recently. Here's a very interesting video about them: ▶ this video
in “Wootz steel” · View on HN
Apparently the Navy also used mechanical 'computers' on old battleships to calculate firing solutions. Sailors would adjust cranks and shafts to set the input values, and those inputs were connected to cams which were machined in the shape of solutions to the equations that needed to be solved. You can watch an old training video about it from the '50s: ▶ this video
in “The Comdyna GP-6 analogue computer that I use daily at work” · View on HN
One of my favourites is this 1953 explanation of the workings of mechanical analog computers used by the US Navy: ▶ this video
in “Walt Disney's MultiPlane Camera (1957) [video]” · View on HN
I recommend watching this video if you're interested in learning about multivariate analysis using mechanical computers. It's very approachable and informative. ▶ this video
in “One of the most complex wristwatches ever made” · View on HN
This old US Navy training film on mechanical fire control calculators (called "computers" back then, used to calculate firing solutions on warships) is pretty fascinating: ▶ this video
in “Optical solutions to NP-Complete problems” · View on HN
Obligatory link to youtube video of a 1950s training video on the mechanical fire control computers (which I stole from HN last time this sort of topic came up): ▶ this video edit: This video is the same footage featured throughout the article, in fact.
in “Gears of war: When mechanical analog computers ruled the waves” · View on HN
analog computers don't generally compute by operating on symbols. For example see the classic video on fire control computers ▶ this video OP's specific phrasing is that they "map symbols to symbols". Analog computers don't do that. Some can, but that's not their definition. Turing machines et al. are a model of computation in mathematics. Humans do math by operating on symbols, so that's why that model operates on symbols. It's not an inherent part of the definition.
in “Is life a form of computation?” · View on HN
> analog computers don't generally compute by operating on symbols. For example see the classic video on fire control computers ▶ this video > OP's specific phrasing is that they "map symbols to symbols". Analog computers don't do that. Some can, but that's not their definition. How is that not symbolic? Fundamentally that kind of computer maps the positions of some rods or gears or what have you to the positions of some other rods or gears or what have you, and the first rods or gears are symbolising motion or elevation or what have you and the final one is symbolising barrel angle or what have you. (And sure, you might physically connect the final gear directly to the actual gun barrel, but that's not the part that's computation; the computation is the part happening with the little gears and rods in the middle, and they have symbolic meanings).
in “Is life a form of computation?” · View on HN
I do hope watchmakers start to integrate "computational" (instead of temporal) complications into their watches, like a mechanical turing machine or other tiny mechanical computers or calculators which I believe have never been constructed this small. Inspiration: Wooden Turing Machine: [link] Curta Calculator: [link] Zuse Z1 Computer: [link] Maybe also analog ones!: ▶ this video
in “Vacheron Constantin breaks the world record for most complicated wristwatch” · View on HN
The engineering knowledge that went into the WWII fire control computers was clearly a form of programming. You will also notice the words "computer", "input", and "output" are used without needing to be explained. ▶ this video
in “Founder Mode, hackers, and being bored by tech” · View on HN
Over the years we have evolved the meaning of computer from something that calculates or reckons to a electronic device that runs software. In reality any black box that has a one-to-one relationship between inputs and outputs can be considered a computer. It might be easier to think of mechanical computers, such as the WW2 fire control computers aboard Navy Ships[0] or more famously the Antikythera mechanism[1]. These are fixed devices, they compute values from inputs. The "program" is stored in the gears camshafts and differentials and ratios between them. Similarly, fixed digital computers such as the Nimatron have their operations stored in relays and digital logic. These sorts of computers don't have a list of instructions. They just have schematics, inputs going through electronic circuits that wind up at outputs. You can do a lot of calculating with just simple logic gates. [0] - ▶ this video [1] - [link]
in “The Nimatron: first 'video game' debuted in 1939” · View on HN
A differential is an adder.[1] This is a differential hooked up as a doubler. Mechanical analog computers, especially gun predictors, had lots of setups like that. [1] ▶ this video
in “Five Hundred and Seven Mechanical Movements (1908)” · View on HN
Interestingly, several months ago I came across the following 1953 training video dealing with this same subject. ▶ this video
in “Gears of war: When mechanical analog computers ruled the waves” · View on HN