The 1953 U.S. Navy training film (MN-6783a) Basic Mechanisms In Fire Control Computers, Part 1: Shafts, Gears, Cams and Differentials discusses some of the mechanisms that are required for the Fire Control Computer to function. The film opens with a Navy crew surrounding a Fire Control Computer (00:48), which solves fire control problems—including the ship’s location, direction, speed, and the enemy ship’s location, direction, and speed—in a matter of seconds so that the ship’s guns may fire accurately and effectively. Though the computer processes the information in seconds, it cannot do its job without the work of Navy men. Men operate the director (01:34), which provides target range and bearing information that is then entered into the computer (01:38). Part 1 of the film uses graphics to show the mechanical operations of shafts, gears, cams, and differentials, all vital mechanisms inside the computer (02:20). Shafts are used to carry values throughout the computer, where a revolution of a shaft corresponds to a numerical value (03:00). Gears are used to transfer values from one shaft to another (04:30); different sizes in gears can change the value of the ratio of shafts for more complex computations. Cams (04:55) are used as computing mechanisms in the computer. They have a working surface and a follower (05:25; 07:25). The film reviews the function of cams and the different types, including a reciprocal cam, square cam, tangent cam, time of flight cam, and barrel cam (10:36). The latter is used to calculate trajectory for firing guns. Differentials (12:50) are the final mechanisms covered in Part 1. They are used in computers to continuously obtain the algebraic sum of two quantities, keeping up with the rapid changes of inputs of two quantities. A bevel gear differential (13:23) is commonly used in Fire Control Computers. The film discusses how this differential functions with its spider gears, spider shaft, and end gears. Simplifying the concept of a bevel gear differential, the film concludes with graphics that explain how the bevel gear differential works using two racks and a pinion.

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This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. For more information visit http://www.PeriscopeFilm.com


  1. Blown away on integers.

  2. Петр Дрогальцев says:

    Хелоу и России! мира всем !

  3. marctronixx says:

    Silly me, I thought this was a video on computers that controlled actual "FIRES", as in burning buildings and such–not "firing" shells and such. However, the video did NOT disappoint!!! Amazing tech. Another home run from Periscope.

  4. Piotr Dudała says:

    [..] obviously, computer accuracy depends on quality of information it receives and that depends on skill and understanding of the man [..] – today, more relevant than ever.

  5. Wild Zero says:

    drink every time the narrator says shaft.

  6. Nelson Malcom says:

    Space… same… WOW! SpaceX landing/Attaching perfect on the ISS . Calculation would be insane using analog, but with that generation it would have been done.

  7. Guy Incognito says:

    Is that’s what’s inside my iPhone?

  8. russell zauner says:

    ANTONIN SVOBODA is the name you are looking for…

  9. When regular maintenance of a computer included lubricating the shafts, gears, bearings etc.
    The "techies" resumes would most likely have listed qualifications such as an "electro- mechanical" background. A term you most likely wouldn't hear today.

  10. facethefaceandmore44 says:

    Imagine if the people making these videos would have guessed that in 70 years time people would still be watching them as the clearest explanation of a subject available. Also love how these computers could deal with infinitely smooth values, something we don't need but can't do anymore (I believe).

  11. Valdis Freibergs says:

    🌅🎡🧒♣️ Main is Distance,For Mechanical Targeting of Gun Man,Side Shots to Movement can Make in Screen by Suggesting A Step of Boat.

  12. Kevin Bratwurst says:

    I always wondered how my PC works. Now I know.

  13. Steve Homeier says:

    Amazing mechanical computer!!! I think my thermostat has more computing power that one of these behemouths

  14. 99% Perspiration says:

    I worked on the Mark 1 fire control computer. They are not blowing smoke when they say that the computation results were immediate. Analog computers have no "clock cycles" that delay the computation result. [the answer to the fire control calculation].

  15. PupPlementary PupPlements says:

    I can now singlehandedly operate a battleship from all of these videos I've watched how fascinating

  16. The wiz kids of old were replaced by 'Black Box' technicians a long time ago (except in the Coast Guard ☺☺☺☺☺ ).

  17. Louie Niglio says:

    You have the physical laborers who build the ships for the use of these fire control systems it's the laborers who work extremely hard working the metal cutting, shaping, welding, lifting and so on then you have the engineers who have to design these fire control systems nothing but pencil and paper along with slide ruler and the only computer available at the time their brain the laborers go home physically exhausted and the engineers go home mentally exhausted.

  18. tunca tunç says:

    IMO, back in those times, engineers could provide simple and beautiful solutions because they can visualize problems.

  19. Alex Shield says:

    wow fascinating how they solved those fire control problems without digital devices.

  20. This was awesome. I learned something tonight!

  21. Patrick Fitzgerald says:

    This is interesting.

  22. Paul Womack says:

    Wow – this film show the principles, which are simple, but to get these analogue computers to have any kind of useful accuracy takes scary levels of precision engineering.

  23. Robert Adamcik says:

    I am a volunteer tour guide at the Battleship WISCONSIN museum in Norfolk, VA. We have our aft gun plot space open to the public, and I love talking about the 30,000 pound, analog computer, built by Ford, that controls the guns. Our guests, especially the young one who never experienced analog technology, are absolutely amazed!

  24. Jonathan Nelson says:

    Wow, this was very educational! I am a software engineer working on modern electronic computers. I have always wondered how details of these old mechanical computers worked. This answered so many of my questions! Thank you for preserving this film. It has never dawned on me that the outputs of various functions would be machined into the gears and cams of a machine. You can see why we switched to digital computers though. Modifications to the weapon systems of a ship, as I understand happened regularly, would require modifications to the computer as well. A modern computer would just upload some new values for the software. These computers would require all new gears and cams. Makes you appreciate the term "software" vs "hardware" a bit more.

    Again, thank you PeriscopeFilm for preserving these films. I love watching these, even the ones that are just advertisements for a product. They give you a better understanding of the people of that time.

  25. James Slick says:

    I am very,very impressed by the analog, mechanical way to handle math. My god, I'm not worthy! Sure I have my PC and smartphone and the digital computing processes behind it all is amazing, but THESE GUYS knew actual math, and how to take an abstract problem and make a fucking, actual, physical MECHANISM to do it.

  26. tacomahnster says:

    There's something about these old videos that is so uplifting and inspirational compared to modern format.

  27. Frederick Wise says:

    Blooinidiotbergs solutions are so full of holes they look like swiss cheese.

  28. USAisJerimiah5133 Mene Tekel Peres says:

    Mechanical mechanisms are the coolest. All variations of mechanical transducers.

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