Remembering The MIT Radiation Laboratory

February 7, 2022 by Chris Lott 31 Comments

Back in the late 80s, our company managed to procure the complete 28 volume MIT Radiation Laboratory (Rad Lab) series, published in 1947, for the company library. To me, these books were interesting because I like history and old technology, but I didn’t understand why everyone was so excited about the acquisition. Only a cursory glimpse at the volumes would reveal that the “circuits” these books described used vacuum tubes and their “computers” were made from mechanical linkages. This was the 1980s, and we worked with modern radar and communications systems using semiconductors, integrated circuits, and digital computers. How could these old musty books possibly be of any practical use? To my surprise, it turned out that indeed they could, and eventually I came to appreciate the excitement. I even used several of them myself over the years.

Radiation Lab? Nuclear Radar?

In the years leading up to WW2, the idea of a civilian organization of scientists that would operate independently of the military and government bureaucracies was being championed by Dr. Vannevar Bush. The military and scientists had not worked well together during the first World War, and it looked like science and technology would be playing a much bigger role in the future.

It seemed certain that America would enter the conflict eventually, and Dr Bush and others believed that a new organizational framework was called for. To that end, the National Defense Research Committee (NDRC), which later became the Office of Scientific Research and Development (OSRD) was pitched to President Roosevelt and he approved it in June of 1940.

Almost immediately, a gift fell in the lap of the new organization — the Tizard Mission which arrived in the states from the UK in Sep 1940. They brought a literal treasure chest of technical innovations from the British, who hoped that US industry’s cooperation could help them survive what looked like certain and imminent invasion. One of those treasures was the cavity magnetron, which our own Dan Maloney wrote about a few years ago.

Within a few weeks, under the guidance of young Welshman “Taffy” Bowen, they had reviewed the design and gathered up the necessary equipment to fire it up. A 10 kV anode power supply and a 1,500 gauss electromagnet were procured, and the scientists gathered at the Bell Radio Laboratories in Whippany New Jersey on Sunday, Oct. 6, 1940. They powered up the cavity magnetron and were blown away by the results — over 10 kW of RF at 3 GHz (10 cm) from something the size of a bar of soap. Continue reading “Remembering The MIT Radiation Laboratory” →

Stinger: The Hacked Machine Gun Of Iwo Jima

February 3, 2020 by Tom Nardi 55 Comments

During the Second World War, the United States was pumping out weapons, aircraft, and tanks at an absolutely astonishing rate. The production of military vehicles and equipment was industrialized like never before, and with luck, never will be again. But even still, soldiers overseas would occasionally find themselves in unique situations that required hardware that the factories back at home couldn’t provide them with.

Which is precisely how a few United States Marines designed and built the “Stinger” light machine gun (LMG) during the lead-up to the invasion of Iwo Jima in 1945. The Stinger was a Browning .30 caliber AN/M2, salvaged from a crashed or otherwise inoperable aircraft, that was modified for use by infantry. It was somewhat ungainly, and as it was designed to be cooled by the air flowing past it while in flight, had a tendency to overheat quickly. But even with those shortcomings it was an absolutely devastating weapon; with a rate of fire at least twice that of the standard Browning machine guns the Marines had access to at the time.

Six Stingers were produced, and at least on a Battalion level, were officially approved for use in combat. After seeing how successful the weapon was during the invasion of Iwo Jima, there was even some talk of putting the Stinger into larger scale production and distributing them. But the war ended before such a plan could be put into place.

As such, the Stinger is an exceedingly rare example of a field modified weapon that was not only produced in significant numbers, but officially recognized and even considered for adoption by the military. But the story of this hacked machine gun actually started years earlier and thousands of kilometers away, as Allied forces battled for control of the Solomon Islands.

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Retrotechtacular: Balloons Go To War

April 25, 2019 by Tom Nardi 5 Comments

To the average person, the application of balloon technology pretty much begins and ends with birthday parties. The Hackaday reader might be able to expand on that a bit, as we’ve covered several projects that have lofted various bits of equipment into the stratosphere courtesy of a high-altitude balloons. But even that is a relatively minor distinction. They might be bigger than their multicolored brethren, but it’s still easy for a modern observer to write them off as trivial.

But during the 1940’s, they were important pieces of wartime technology. While powered aircraft such as fighters and bombers were obviously more vital to the larger war effort, balloons still had numerous defensive and reconnaissance applications. They were useful enough that the United States Navy produced a training film entitled History of Balloons which takes viewers through the early days of manned ballooning. Examples of how the core technology developed and matured over time is intermixed with footage of balloons being used in both the First and Second World Wars, and parallels are drawn to show how those early pioneers influenced contemporary designs.

Even when the film was produced in 1944, balloons were an old technology. The timeline in the video starts all the way back in 1783 with the first piloted hot air balloon created by the Montgolfier brothers in Paris, and then quickly covers iterative advancements to ballooning made into the 1800’s. As was common in training films from this era, the various “reenactments” are cartoons complete with comic narration in the style of W.C. Fields which were designed to be entertaining and memorable to the target audience of young men.

While the style might seem a little strange to modern audiences, there’s plenty of fascinating information packed within the film’s half-hour run time. The rapid advancements to ballooning between 1800 and the First World War are detailed, including the various instruments developed for determining important information such as altitude and rate of climb. The film also explains how some of the core aspects of manned ballooning, like the gradual release of ballast or the fact that a deflated balloon doubles as a rudimentary parachute in an emergency, were discovered quite by accident.

When the film works its way to the contemporary era, we are shown the process of filling Naval balloons with hydrogen and preparing them for flight. The film also talks at length about the so-called “barrage balloons” which were used in both World Wars. Including a rather dastardly advancement which added mines to the balloon’s tethers to destroy aircraft unlucky enough to get in their way.

This period in human history saw incredible technological advancements, and films such as these which were created during and immediately after the Second World War provide an invaluable look at cutting edge technology from a bygone era. One wonders what the alternative might be for future generations looking back on the technology of today.

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Recreating Classic Model Kits With Modern Tech

April 5, 2019 by Tom Nardi 17 Comments

It used to be that if you wanted to make a nice scale model of an airplane, you’d be building the frame out of thin balsa ribs and covering it all up with tissue paper. Which incidentally was more or less how they built most real airplanes prior to the 1930s, so it wasn’t completely unreasonable to do the same on a smaller scale. But once injection molded plastics caught on, wood and tissue model kits largely went the way of the dodo.

[Marius Taciuc] wanted to share that classic model building experience with his son, but rather than trying to hunt down balsa kits in 2019, he decided to recreate the concept with modern techniques. His model of the Supermarine Spitfire, the vanguard of the British RAF during the Second World War, recreates the look of those early model kits but substitutes 3D printed or laser cut components for the fragile balsa strips of yore. The materials might be high-tech, but as evidenced by the video after the break, building the thing is still just as time consuming as ever.

Using a laser cutter to produce the parts would be the fastest method to get your own kit put together (you could even cut the parts out of balsa in that case), but you’ll still need a 3D printer for some components such as the propeller and cowling. On the other hand, if you 3D print all the parts like [Marius] did, you can use a soldering iron to quickly and securely “weld” everything together. For anyone who might be wondering, despite the size of the final plane, all of the individual components have been sized so everything is printable on a fairly standard 200 x 200 mm print bed.

While there’s no question the finished product looks beautiful, some might be wondering if it’s really worth the considerable effort and time necessary to produce and assemble the dizzying number of components required. To that end, [Marius] says it’s more of a learning experience than anything. Sure he could have bought a simplified plastic Spitfire model and assembled it with his son in an afternoon, but would they have really learned anything about its real-world counterpart? By assembling the plane piece by piece, it gives them a chance to really examine the nuances of this legendary aircraft.

We don’t often see much from the modeling world here on Hackaday, but not for lack of interest. We’ve always been in awe of the lengths modelers will go to get that perfect scale look, from the incredible technology packed into tiny fighter planes to large scale reproductions of iconic engines. If you’ve got some awesome model making tips that you think the Hackaday readership might be interested in, don’t be shy.

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Retrotechtacular: Weather Station Kurt

October 18, 2017 by Jenny List 24 Comments

Sometimes when researching one Hackaday story we as writers stumble upon the one train of thought that leads to another. So it was with a recent look at an unmanned weather station buoy from the 1960s, which took us on a link to a much earlier automated weather station.

The restored Kurt in the Canadian National War Museum.

Weather Station Kurt was the only successful installation among a bold attempt by the German military during the Second World War to gain automated real-time meteorological data from the Western side of the Atlantic. Behind that simple sentence hides an extremely impressive technical and military achievement for its day. This was the only land-based armed incursion onto the North American continent by the German military during the entire war. Surrounded as it was though by secrecy, and taking place without conflict in an extremely remote part of Northern Labrador, it passed unnoticed by the Canadian authorities and was soon forgotten as an unimportant footnote in the wider conflagration.

Kurt took the form of a series of canisters containing a large quantity of nickel-cadmium batteries, meteorological instruments, a telemetry system, and a 150W high frequency transmitter. In addition there was a mast carrying wind speed and direction instruments, and the transmitting antenna. In use it was to have provided vital advance warning of weather fronts from the Western Atlantic as they proceeded towards the European theatre of war, the establishment of a manned station on enemy territory being too hazardous.

A small number of these automated weather stations were constructed by Siemens in 1943, and it was one of them which was dispatched in the U-boat U537 for installation on the remote Atlantic coast of what is now part of modern-day Canada. In late October 1943 they succeeded in that task after a hazardous trans-Atlantic voyage, leaving the station bearing the markings of the non-existent “Canadian Meteor Service” in an attempt to deceive anybody who might chance upon it. In the event it was not until 1977 that it was spotted by a geologist, and in 1981 it was retrieved and taken to the Canadian War Museum.

There is frustratingly little information to be found on the exact workings on the telemetry system, save that it made a transmission every few hours on 3940kHz. A Google Books result mentions that the transmission was encoded in Morse code using the enigmatic Graw’s Diaphragm, a “sophisticated contact drum” named after a Dr. [Graw], from Berlin. It’s a forgotten piece of technology that defies our Google-fu in 2017, but it must in effect have been something of a mechanical analogue-to-digital converter.

Should you happen to be visiting the Canadian capital, you can see Kurt on display in the Canadian War Museum. It appears to have been extensively restored from the rusty state it appears in the photograph taken during its retrieval, it would be interesting to know whether anything remains of the Graw’s Diaphragm. Do any readers know how this part of the station worked? Please let us know in the comments.

Weather station Kurt retrieval image, Canadian National Archives. (Public domain).

Weather station Kurt in museum image, SimonP (Public domain).