U.S. NAVY BASIC MECHANISMS OF FIRE CONTROL COMPUTERS MECHANICAL COMPUTER INSTRUCTIONAL FILM 27794
Why Hacker News recommends it
HN treats it as the classic demonstration of how analog mechanical computation works, especially the differential gear section.
What it is
A 1953 US Navy training film on the basic mechanisms in fire control computers: shafts, gears, cams and differentials. It shows how these mechanical parts compute ship and target firing solutions.
Recommended by 11 HN commenters across 11 different months, 2018 to 2026.
What Hacker News said
Strong rec ethbr1 · 2023-11 · on “Lost Doctor Who episodes found but owner is reluctant to hand them to BBC”
Two gems (among many)... Periscope Films (on YouTube): [LINK] Digitized 40-60s era reels. It still amazes me how effectively they presented complex topics then. E.g. mechanical naval gunnery computers: [this video] And this on-the-ground movie on the Columbia student occupation in 1968: [LINK]
Recommends jeffwass · 2018-08 · on “Tide-Predicting Machine No. 2”
You might like this video about the US Navy fire control computer. Mechanical yet also programmable. Eg with cam-based calculation modules like 1/x or differential gearings to perform addition : [this video]
Recommends Scaevolus · 2019-09 · on “UCLA’s 1948 Mechanical Computer [video]”
If you want more information on how you can do computation with mechanical systems, try this video: U.S. NAVY BASIC MECHANISMS OF FIRE CONTROL COMPUTERS MECHANICAL COMPUTER INSTRUCTIONAL FILM 27794 [this video]
Recommends tzs · 2020-04 · on “How to Use a Differential Analyzer”
This could use a lot more visual aids. Here's a film that goes over a lot of the basics: "BASIC MECHANISMS IN FIRE CONTROL COMPUTERS" [1]. It's a 1953 US Navy instructional film explaining how mechanical fire control computers worked. These machines took inputs giving the speed and direction the ship was traveling, the speed and direction the target was moving, the distance and direction to the target, the wind speed and direction, and other factors, and computed how to aim the guns to shell the target. [1] [this video]
Recommends fallous · 2020-10 · on “Show HN: What would mechanical programming look like?”
I went a bit further back when I saw "mechanical programming" and thought of this video. [this video] Mechanical analog computing FTW!
Recommends segfaultbuserr · 2020-12 · on “1937 film explains how a car differential works”
If you enjoy this, don't miss the video lecture on World War 2-era mechanical fire control computers by the U.S. Navy. I learned you can do a lot of computations with gears and shafts. [this video]
Recommends dragontamer · 2022-04 · on “Why a Slide Rule Works”
So I've known about slide-rules for a while. What I didn't realize was that the mechanical principles of slide-rules were applied to fire-control computers on WW2-era Battleships. [LINK] These computers had slide-rule like cylinders that would rotate. As you aimed the gun sights "at" a target, the gun's coordinates were being mapped to a cylinder, which would move the gun a different direction (you have to aim the gun "higher" the further away the target is, to account for gravity "drooping" the bullet). In effect; the weirdly shaped cylinder inside the fire-control computer is a pre-computed solution that maps x/y coordinate inputs to a z-coordinate output (where "z" would be fed into the g
Recommends pkaye · 2022-05 · on “Collection of US Navy Training Courses Developed”
The US Navy had this great video on principles of mechanical computers. Using cams and gears to compute functions. [this video]