Ballistic computer of 1935: the 3-ton "Big Brain"


14 Responses to “Ballistic computer of 1935: the 3-ton "Big Brain"”

  1. RUKind says:

    This thing looks a bit like a horizontal Jacquard loom. We got punch cards from Jacquard looms – that’s how their designs were “programmed” in. There’s an interesting PBS show, pretty old at this point, of how cotton farming in Egypt gave rise to the modern computer.

    Farming -> clothing -> cotton -> weaving -> trade -> trade routes -> fiefdoms – protection of trade routes -> castle/forts -> -> seiges; longbow -> crossbow -> catapult; gunpowder -> blunderbus -> cannon -> ballistics -> complex math to solve parabola of projectile -> this analog blunderbus above -> ENIAC; cotton -> cloth -> hand looms -> mechanical looms -> Jacquard looms -> punch cards to program Jacquard loom designs -> ENIAC.

    And then there was COBOL which begat…

    If I have any bits (no pun) wrong, feel free to correct me.

  2. Anonymous says:

    The photo appears to be a “ballistic” rather than a “fire control” computer. A ballistic computer is used to come up with the tables and profile the cams that would later be used to fire artillery. You have to figure out what the constants are for x shell with y charges at z temperature before you can write the firing tables and machine the fire control computer.

  3. wolfwitch says:

    I remember back in the mid-’80s taking a tour of an active-duty battleship while in the Navy. It used huge electro-mechanical computers for the fire control of its big guns. They took up a substantial part of the ship itself, and were definitely “old-school” even at that time. But- according to the officer showing us around- modern computers weren’t any more accurate, so they had no reason to replace them.

  4. Robert says:

    They worked really well. Until you got your tie caught in it.

  5. SAE Miller says:

    One interesting point overlooked: This is an analogue computer, today these problems are solved by digital computers.

  6. John Lupien says:

    Feinman goes into some detail about
    his work on mechanical balistic computers
    in “Surely you’re joking, Mr. Feinman”

  7. Ed_Fuller says:

    #8 — I once worked with an engineer that had worked in an aircraft factory in WWII. He described the process of doing a stress calculation as:

    1. Engineer sets up the problem with the appropriate numbers.
    2. Papers are passed to another section that converts all the numbers to logarithms and corresponding necessary addition/subtraction problems.
    3. Results checked for accuracy, then are attached to the original papers and passed to a third section.
    4. This section is full of women (it was WWII) with mechanical adding machines. Here they did all the adding and subtracting of the logs.
    5. Results were checked for accuracy, attached to the paperwork and returned to the previous group.
    6. Results were translated back to real numbers from the logs and checked for accuracy.
    7. Results were then passed back to the engineer.

    This normally took about a week to do unless you had full priority which you “might” get your results in 3 days.

    Remember, this is for ONE loop around the design process; if it wasn’t strong enough, you got to do it again. Also, there was no “cut-and-paste” for entering the numbers. You had to key in each number every time you wanted to perform a calculation. If the adding machine papertape was lost, you got to do the whole calculation all over again. Imagine trying to optimize something!

    Obviously, this process wasn’t used for all their calculations. They had their sliderules, hand calculations, and engineering handbooks for quick-and-dirty stuff, but this was the general process for the large critical calculations.


  8. blacklabelsk8erX says:

    Yes, Sae Miller is correct, this is a Differential analyser, which was analog. This was a pretty advanced one, but the first had been around a few years prior. is a neat site to look at for more info. Meccano look cooler than Legos definitely, can’t build your own Difference Engine with Legos. Perhaps you can, I’m just not that clever.

  9. ankh says:

    See, the Heinleins didn’t have a big enough garage nor enough electricity available for one of these, that’s why

    “writing the description of how they got to that station required the famous three days of paper-and-pencil calculations (see Expanded Universe, pp. 519-520) for one line of writing. John Campbell would have been pleased to learn of this, but Heinlein was now writing for an editor who did not appreciate such effort.”

    I recall somewhere Heinlein describes the same kind of effort, days with a pencil and paper, doing the calculations for “Destination Moon.”

  10. lowlights says:

    Clearly – the analog computer eventually evolved into the Fusbol Table.

  11. diluded000 says:

    Solving the earth-moon-projectile gravity thing with a mechanical device is really interesting. I had heard of a ballistics type computer. But I always heard it described as artillery trajectories, and it seemed like a table of trig functions would have worked for that. This makes much more sense.

    I had to implement the Runge-Cutta Feldberg (I think) algorithm in Fortran for a class one time to generate a set of plot points for a projectile leaving the earth and passing the moon. I don’t recall what order differential equation it was, but having to compute each point by hand would definitely be a week long endeavor.

  12. tomic says:

    You can larf at them now, but the main problems with them is setup of a problem, aka “programming”. Once done, however, many analog machines “compute” instantaneously. Besides the obvious bulk, and setup hassles, accuracy is limited to 3? or so decimal points.

    THe scalability of precision is what made digit-based calculations attractive (keep in mind that automatic, electronic, digital, computers were much, much larger than mechanical calculators for over a decade).

    Improvements in analog precision gets very expensive very fast. 5 digits is more or less resolving 10 microvolts out of one volt; 6 digits is one microvolt; most amplifier noise is in the tens of microvolts range. The cost scale is geometric.

    To double digital precision you simply build another row (or column, …) of the same stuff as before. Cost scale is linear.

    Analog modeling is really attractive in some ways; when done right, it’s equivelant to parallelism still unthinkable in digital terms. And often the real-time nature is more important than accuracy, especially in closed-loop problems.

  13. eigenmind says:

    You can actually see one of these machines at work in the 1956 film “Earth vs. the flying saucers” (at –more or less- 56 minutes from the start). The data output device shown on the film is graphical, but seems, however, very advanced (even by the present standards):).
    In the film you can also see the panels in the walls to store the little wheels used to “program” the thing.

    A modern and extremely beautiful recreation of one of these computers was done by Tatjana van Vark. ( )
    Seems SteamPunk, but is a completely different level.

  14. lamarlowe says:

    My old head feels heavy. Somewhat sorry for the short comment, but I’m playing with my new Asus Eee, which has no vacuum tubes, but is cool as all hell, hard to type on, but it beats flipping switches for each card. lemme see, colon right parend….. :)

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