wwii

39 Articles

Retrotechtacular: The TV Bombs Of WWII

November 14, 2024 by 40 Comments

Anyone who was around for the various wars and conflicts of the early 2000s probably recalls the video clips showing guided bombs finding their targets. The black-and-white clips came from TV cameras mounted in the nose of the bomb, and were used by bombardiers to visually guide the warhead to the target — often providing for a level of precision amounting to a choice of “this window or that window?” It was scary stuff, especially when you thought about what was on the other side of the window.

Surprisingly, television-guide munitions aren’t exactly new, as this video on TV-guided glide bombs in WWII indicates. According to [WWII US Bombers], research on TV guidance by the US Army Air Force started in 1943, and consisted of a plywood airframe built around a standard 2000-pound class gravity bomb. The airframe had stubby wings for lift and steerable rudders and elevators for pitch and yaw control. Underneath the warhead was a boxy fairing containing a television camera based on an iconoscope or image orthicon, while all the radio gear rode behind the warhead in the empennage. A B-17 bomber could carry two GB-4s on external hardpoints, with a bulky TV receiver provided for the bombardier to watch the bomb’s terminal glide and make fine adjustments with a joystick.

In testing, the GB-4 performed remarkably well. In an era when a good bombardier was expected to drop a bomb in a circle with a radius of about 1,200′ (365 meters) from the aim point, GB-4 operators were hitting within 200′ (60 meters). With results like that, the USAAF had high hopes for the GB-4, and ordered it into production. Sadly, though, the testing results were not replicated in combat. The USAAF’s 388th Bomber Group dropped a total of six GB-4s against four targets in the European Theater in 1944 with terrible results. The main problem reported was not being able to see the target due to reception problems, leaving the bombardiers to fly blind. In other cases, the bomb’s camera returned a picture but the contrast in the picture was so poor that steering the weapon to the target was impossible. On one unfortunate attack on a steel factory in Duren, Germany, the only building with enough contrast to serve as an aiming point was a church six miles from the target.

The GB-4’s battlefield service was short and inglorious, with most of the 1,200 packages delivered never being used. TV-guided bombs would have to wait for another war, and ironically it would be the postwar boom in consumer electronics and the explosion of TV into popular culture would move the technology along enough to make it possible.

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Bogey Six O’clock!: The AN/APS-13 Tail Warning Radar

October 31, 2024 by 20 Comments

Although we think of air-to-air radar as a relatively modern invention, it first made its appearance in WWII. Some late war fighters featured the AN/APS-13 Tail Warning Radar to alert the pilot when an enemy fighter was on his tail. In [WWII US Bombers]’ fascinating video we get a deep dive into this fascinating piece of tech that likely saved many allied pilots’ lives.

Fitted to aircraft like the P-51 Mustang and P-47 Thunderbolt, the AN/APS-13 warns the pilot with a light or bell if the aircraft comes within 800 yards from his rear. The system consisted of a 3-element Yagi antenna on the vertical stabilizer, a 410 Mhz transceiver in the fuselage, and a simple control panel with a warning light and bell in the cockpit.

In a dogfight, this allows the pilot to focus on what’s in front of him, as well as helping him determine if he has gotten rid of a pursuer. Since it could not identify the source of the reflection, it would also trigger on friendly aircraft, jettisoned wing tanks, passing flak, and the ground. This last part ended up being useful for safely descending through low-altitude clouds.

This little side effect turned out to have very significant consequences. The nuclear bombs used on Hiroshima and Nagasaki each carried four radar altimeters derived from the AN/APS-13 system.

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Retrotechtacular: Making Enough Merlins To Win A War

October 25, 2024 by 16 Comments

From the earliest days of warfare, it’s never been enough to be able to build a deadlier weapon than your enemy can. Making a sharper spear, an arrow that flies farther and straighter, or a more accurate rifle are all important, but if you can’t make a lot of those spears, arrows, or guns, their quality doesn’t matter. As the saying goes, quantity has a quality of its own.

That was the problem faced by Britain in the run-up to World War II. In the 1930s, Rolls-Royce had developed one of the finest pieces of engineering ever conceived: the Merlin engine. Planners knew they had something special in the supercharged V-12 engine, which would go on to power fighters such as the Supermarine Spitfire, and bombers like the Avro Lancaster and Hawker Hurricane. But, the engine would be needed in such numbers that an entire system would need to be built to produce enough of them to make a difference.

“Contribution to Victory,” a film that appears to date from the early 1950s, documents the expansive efforts of the Rolls-Royce corporation to ramp up Merlin engine production for World War II. Compiled from footage shot during the mid to late 1930s, the film details not just the exquisite mechanical engineering of the Merlin but how a web of enterprises was brought together under one vast, vertically integrated umbrella. Designing the engine and the infrastructure to produce it in massive numbers took place in parallel, which must have represented a huge gamble for Rolls-Royce and the Air Ministry. To manage that risk, Rolls-Royce designers made wooden scale models on the Merlin, to test fitment and look for potential interference problems before any castings were made or metal was cut. They also set up an experimental shop dedicated to looking at the processes of making each part, and how human factors could be streamlined to make it easier to manufacture the engines.

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How To Properly Patch Your Iowa-Class Battleship

April 6, 2024 by 28 Comments

There’s a saying among recreational mariners that the word “boat” is actually an acronym for “bring out another thousand”, as it seems you can’t operate one for long without committing to expensive maintenance and repairs. But this axiom isn’t limited to just civilian pleasure craft, it also holds true for large and complex vessels — although the bill generally has a few more zeros at the end.

Consider the USS New Jersey (BB-62), an Iowa-class battleship that first served in the Second World War and is now operated as a museum ship. Its recent dry docking for routine repair work has been extensively documented on YouTube by curator [Ryan Szimanski], and in the latest video, he covers one of the most important tasks crews have to attend to while the ship is out of the water: inspecting and repairing the hundreds of patches that line the hull.

These patches aren’t to repair damage, but instead cover up the various water inlets and outlets required by onboard systems. When New Jersey was finally decommissioned in 1991, it was hauled out of the water and plates were welded over all of these access points to prevent any potential leaks. But as the Navy wanted to preserve the ship so it could potentially be reactivated if necessary, care was taken to make the process reversible.

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Daily Inspections Keep Your Spitfire In Tip-Top Shape

October 18, 2023 by 22 Comments

What ho, chaps? Look, we know this is a bally nuisance and all, but those desk jockeys at HQ want us all to watch this film about daily insepction of your Spitfire. No Vera and no Greta in this one, more’s the pity, but it is jolly important. We all know that our Spitfires are complicated buckets of bolts, but those kites won’t stay in the air if we don’t maintain them. Yes, the boring stuff, like purging the fuel system of water and refueling outside of the hanger. And, yes, Captain Molesworth, that means putting out that cigar while the tech boys are topping off your tank. Now shut up and watch the film we’ve placed below the break, what?

All right, all right, wake up at the back there. I heard you snoring, Peason. The bally Germans could hear you snoring. I know that wasn’t Errol Flynn, but this stuff is damned essential. You may be pilots, but you all rely on those people you just saw. Your lives depend on the riggers, armorers, instrument repairers, and others. While you are out carousing, these men are taking your plane apart and ensuring the engine is running smoother than the legs of the barmaid at the Dog & Duck. Every time one of you chaps calls Bingo Fuel, you get home because some chap checked your fuel gauge was accurate. Every time one of you glances at the Rate of Climb indicator to judge an intercept, you are relying on the chap who tested and zeroed it while you were snoring in your bunk, sleeping off last nights debauch. So, don’t forget that you are part of a team. You may be full of dauntless spirit  up there, but you won’t get anywhere without those chaps on the ground.

Now, let’s talk about tonight’s mission…

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Weather In Wartime: The Importance Of British Meteorology In WWII

July 24, 2023 by 10 Comments

Weather can have a significant impact on transport and operations of all kinds, especially those at sea or in the air. This makes it a deeply important field of study, particularly in wartime. If you’re at all curious about how this kind of information was gathered and handled in the days before satellites and computer models, this write-up on WWII meteorology is sure to pique your interest.

Weather conditions were valuable data, and weather forecasts even more so. Both required data, which relied on human operators for instruments to be read and their readings transmitted.

The main method of learning weather conditions over the oceans is to persuade merchant ships to report their observations regularly. This is true even today, but these days we also have the benefit of things like satellite technology. Back in the mid-1900s there was no such thing, and the outbreak of WWII (including the classification of weather data as secret information due to its value) meant that new solutions were needed.

The aircraft of the Royal Air Force (RAF) were particularly in need of accurate data, and there was little to no understanding of the upper atmosphere at the time. Eventually, aircraft flew regular 10-hour sorties, logging detailed readings that served to provide data about weather conditions across the Atlantic. Readings were logged, encoded with one-time pad (OTP) encryption, then radioed back to base where charts would be created and updated every few hours.

The value of accurate data and precise understanding of conditions and how they could change was grimly illustrated in a disaster called the Night of the Big Wind (March 24-25, 1944). Forecasts predicted winds no stronger than 45 mph, but Allied bombers sent to Berlin were torn apart when they encountered winds in excess of 120 mph, leading to the loss of 72 aircraft.

The types of data recorded to monitor and model weather are nearly identical to those in modern weather stations. The main difference is that instruments used to be read and monitored by human beings, whereas today we can rely more on electronic readings and transmission that need no human intervention.

Retrotechtacular: Circuit Potting, And PCBs The Hard Way

June 15, 2023 by 8 Comments

There was a time when the very idea of building a complex circuit with the intention of destroying it would have been anathema to any electrical engineer. The work put into designing a circuit, procuring the components, and assembling it, generally with point-to-point wiring and an extravagant amount of manual labor, only to blow it up? Heresy!

But, such are the demands of national defense, and as weapons morphed into “weapon systems” after World War II, the need arose for electronics that were not only cheap enough to blow up but also tough enough to survive the often rough ride before the final bang. The short film below, simply titled “Potted and Printed Circuits“, details the state of the art in miniaturization and modularization of electronics, circa 1952. It was produced by the Telecommunications Research Establishment (TRE), the main electronics R&D entity in the UK during the war which was responsible for inventions such as radar, radio navigation, and jamming technology.

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