Range-finding and Fire Control - Plotting Your Demise

Comments · 2.6K

• DR

  @Drachinifel · 6 years ago · pinned

  Pinned post for Q&A :)

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• TO

  @tomsemmens6275 · 6 years ago

  I made my nephew an optical rangefinder as a way of teaching him trigonometry. We pretended we were working out the range of enemy ships, he still thinks it was the best maths lessons he ever had.

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• MA

  @MatthewSmith-sz1yq · 5 years ago

  &quot;Genetic hybridization with a hammerhead shark is... frowned upon.&quot; <br><br>Someone needs to make a compilation of these jokes, they are gold!

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• WH

  @WhisperingDeath · 6 years ago

  Before this video: how did these navy guys manage to shoot at eachother so much and miss so often?<br>After this video: wow it&apos;s a miracle any shell ever hit the target

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• TA

  @TachiTekmo · 6 years ago

  This is why the FCO says, &quot;I have a firing solution.&quot; They were <i>literally</i> solving a trigonometry problem. Those Ford Mk.I computers are a pure marvel of mechanical engineering. Just absolutely amazing.

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• NA

  @nathanokun8801 · 6 years ago

  This talk is one of the best discussions on this topic I have ever heard. &nbsp;After 41 years of work on such systems for the US Navy (both guided missile and gun systems), I have A LOT of knowledge about this and this instructor HAS NAILED IT!!! &nbsp;This instructor is WAY, WAY, WAY better at such discussions than most other people I have ever heard. &nbsp;THANK YOU, DRACHINIFEL!!!!!!!

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• BI

  @bificommander · 6 years ago

  You gotta feel sorry for the Italian designer who jammed the Littorio full of the best rangefinding and fire control equipment he could build, only for the shell manufacturers to render all his work pointless.<br>Teamwork: Ensuring your hard work can always be ruined by someone else.

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• KY

  @kyle857 · 6 years ago

  Before your channel, I had no idea how sophisticated these systems were.

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• ON

  @onejokeman2002 · 6 years ago

  Optically: I see that we&apos;ll definitely hit that target<br>Depression: We&apos;ll never hit that target

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• NA

  @nathanokun8801 · 6 years ago

  Some more &quot;fun&quot; things&quot;<br><br>(1) &nbsp;When several ships were firing at a single target, you had a MAJOR problem of figuring out whose shells were landing where so that you could adjust your guns&apos; aim point. &nbsp;This started to be a problem in WWI battles when director/computer control of all of the guns became the rule. &nbsp;(This was before radar eventually helped show your shells in flight and thus the ability to see which ones were yours from the fire-control radar operator, if he was good.) &nbsp;The US, France, and Japan after WWI decided to try to fix this problem, though interestingly, the British and Germans did not (to my knowledge). &nbsp;The thing to do was to give each ship&apos;s shells some way of making their hit at the target area different enough to, at least in good visibility and during daylight, allow the spotters with their telescopes to sort out what to report to the fire-control personnel to adjust the gun calculations on the computer. &nbsp;The method was colored dye in the shell windscreen (the sheet-metal hollow false nose of the shell to make it more streamlined without compromising the usually-much blunter projectile nose and, if fitted, armor-penetrating (AP) cap on the actual shell nose). &nbsp;The US system had a simple paper bag full of a colored powdered dye, each ship in a group using its own color powder, and some spot-welded-over holes in the windscreen to let the water on impact slam through the windscreen interior to color the water-impact splash -- it did not work at night or in low visibility or, unfortunately, if a direct hit on the target occurred (kind of a bummer, that last fact!). &nbsp;The Japanese, in their post-1931 major caliber gun (6.1&quot; (155mm) and up) Type 91 and later Type 1 AP shells, was effectively identical, but had the entire windscreen tear off the nose on water (or any other) impact to allow the now-flat-faced shell to travel underwater nose-first for a long distance in the hope of hitting the enemy warship well below the waterline if the shell hit short of the target, so it acted like a tiny torpedo on such hits (they also made the shell fuze delay extremely long to help this, which caused some problems with hitting thin armor on an actual target direct hit, a negative aspect of this shell design). &nbsp;The French, as they usually did, went to a more elaborate and &quot;elegant&quot; solution for their new 33cm (13&quot;) and 38cm (14.96&quot;) battleship guns: &nbsp;The dye bag was increased in size and supported by a framework near the tip of the windscreen; the windscreen was enlarged -- making these the most streamlined shells used in any warship gun ever, to my knowledge -- and a strong base was crimped/screwed to the face of the shell&apos;s AP cap to rigidly support it; and, uniquely, the tip of the nose of the windscreen had the instantaneous nose fuze and booster charge of their high explosive (HE) shells used for shore bombardment and shooting at small, unarmored enemy ships. &nbsp;On impact with anything whatsoever, the nose fuze would go off, making a colored flash and large puff of smoke, visible at night and even in some low-visibility conditions and, the best point, on a direct hit, too. &nbsp;More expensive and making the shell have to be handled with care due to the exposed nose fuze (as did any HE shell, though), but it solved all of the problems. &nbsp;When the British got some French naval material from refugee warships after the fall of France in 1940, they decided that the French design of this was good enough to add to their battleship AP ammo -- they had had some problems when their cruisers were firing at the German &quot;Pocket Battleship&quot; ADMIRAL GRAF SPEE in 1940 due to this shell-sorting problem -- and they thus created their &quot;K&quot; AP shells with this kind of nose-fuzed dye bag to their new and refitted AP shells, though they did not change the windscreen shape so that the shells kept their old ballistics. &nbsp;Germany, probably due to having so few warships, never used this dye bag option.<br><br>(2) &nbsp;At the start of WWII most ships used the &quot;follow the pointer&quot; system to aim their guns, where personnel in the turret would manually adjust their traverse and elevation controls of the mount using a pointer dial set by the calculator (either the central ship calculator in normal control or some backup in-turret calculator using its own inputs in local control); he did not usually see the target he was shooting at himself. &nbsp;Just prior to and during WWII, the US and Germany and, eventually, Britain, developed their own forms of what the US Navy called &quot;Remote Power Control&quot; (RPC), where the calculated values were amplified reliably enough to directly be input into the controls and the human controllers became backup/emergency use only. &nbsp;To do this required the amplification of the signal with the aiming orders without changing its value by more than 0.001 degree or so (even a small error could make a big difference at longer ranges or against higher-speed targets, especially with anti-aircraft fire). &nbsp;Attempts to do this with direct-current &quot;stepping-motor&quot; systems -- most warships used DC power systems throughout at this time -- with tiny jumps from value to value, as in the second hands of some clocks, had never been successful, with errors jumping upward in sync with the signal strength needed to run the controls automatically. &nbsp;What was needed was a very fine control range method that could be amplified in strength with no change in the error. &nbsp;The solution was to change to alternating-current (AC) signals and use transformers -- the same method used in homes to change the higher-power electrical pole voltages to the much lower one used in the home wall outlets -- to adjust the signal strength up and down. &nbsp;To keep the same error required a very precise way to measure the values being transmitted (any signal could be converted to this system, not just angles for gun aiming, note) and a way to shift the signal strength without changing the precision of the original measurement/calculation (this can go to and from any device, not just from the computer to a gun mount). &nbsp;The solution used by the US Navy was the &quot;synchro&quot; or &quot;selsyn&quot; (&quot;self-synchronization&quot;) technique. &nbsp;The information to be transmitted was changed to an angle value on a 360-degree dial by appropriate gearing/electrical conversion and then this was sent to the transmitter for output. &nbsp;The transmitter had a magnetized needle on a pivot that rotated to the angle given to it. &nbsp;Around the needle in an equilateral triangular set of three AC electromagnets was placed on the same plane as the needle, so when the needle moved, it changed the strength of the output to each of the three coils slightly in a unique manner for any angle value. &nbsp;These three currents could be put into a single voice-radio-style transformer/amplifier to boost all three by exactly the same amount and this boosted current sent to the receiver where it too had the three coils and its own magnet needle, which the now-strong signal on the three coils pushed to match the position of the needle in the original transmitter. &nbsp;Shazam, the signal was &quot;teleported&quot; to the device attached to the receiver, no matter where it might be on the ship. &nbsp;To handle slop in the needle position, a second geared needle system with a 36-to-1 geared needle (10-degree range) was also created by the transmitter and sent parallel to the the 1-to-1 signal and, using a simple geared or electrical network, the two were combined to make the final geared needle output match the original one within any accuracy desired (even higher secondary adjustment needle ratios could be used if, rarely, even higher precision was needed). &nbsp;Instead of vacuum-tube-enhanced transformers, the Germans used magnetic amplifiers (also used by the US in some systems after WWII) with similar results. &nbsp;The original British system, the &quot;Magslip&quot;, was a hybrid requiring the human to move the controls to within 10 degrees of the aim point before the RPC could cut in; it was replaced after WWII by a more conventional fully RPC system, as was done by everybody else. &nbsp;Against surface ships, which were rather slow for the most part, the follow-the-pointer system worked OK, but it failed badly during WWII against smaller attacking aircraft -- not straight-line horizontal bombers -- as the aircraft got faster and more maneuverable. &nbsp;The analog synchro-type systems remained in use until digital equipment began to replace them during the 1970s, though it took many years to finally do this, given the slow overhaul rate of warships and the &quot;if it works, don&apos;t fix it&quot; logic when using older equipment...

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• SH

  @shananagans5 · 5 years ago

  Great presentation. My grandmother was a &quot;computer&quot; in WWII. She was one of the women that made the pre calculated tables. She later worked as a math teacher. I must say it was hell growing up having to explain to her that I was terrible at math and didn&apos;t even like it. However, it is cool that she had an important job in WWII. The computers were highly respected.

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• TU

  @turbowolf302 · 6 years ago

  &quot;I took ballistics in school. Fascinating subject. Things go up, things go down!&quot;

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