Retrotechtacular: Synchros Go To War (and Peace)

April 25, 2018 by Al Williams 41 Comments

Rotation. Motors rotate. Potentiometers and variable capacitors often rotate. It is a common task to have to rotate something remotely or measure the rotation of something. If I asked you today to rotate a volume control remotely, for example, you might offer up an open loop stepper motor or an RC-style servo. If you wanted to measure a rotation, you’d likely use some sort of optical or mechanical encoder. However, there’s a much older way to do those same tasks and one that still sees use in some equipment: a synchro.

The synchro dates back to the early 1900s when the Panama Canal used them to read and control valves and gates. These devices were very common in World War II equipment, too. In particular, they were often part of the mechanisms that set and read gun azimuth and elevation or — like the picture to the left — a position indication of a radar antenna. Even movie cameras used these devices for many years. Today, with more options, you don’t see them as much except in applications where their simplicity and ruggedness is necessary.

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Milspec Teardown: CP-142 Range Computer

February 19, 2018 by Tom Nardi 69 Comments

As some of my previous work here at Hackaday will attest to, I’m a big fan of World War II technology. Something about going in with wooden airplanes and leaving with jet fighters and space capable rockets has always captivated me. So when one of my lovingly crafted eBay alerts was triggered by something claiming to be a “Navy WWII Range Computer”, it’s safe to say I was interested.

Not to say I had any idea of what the thing was, mind you. I only knew it looked old and I had to have it. While I eagerly awaited the device to arrive at my doorstep, I tried to do some research on it and came up pretty much empty-handed. As you might imagine, a lot of the technical information for hardware that was developed in the 1940’s hasn’t quite made it to the Internet. Somebody was selling a technical manual that potentially would have covered the function of this device for $100 on another site, but I thought that might be a bit excessive. Besides, where’s the fun in that?

I decided to try to decipher what this device does by a careful examination of the hardware, consultation of what little technical data I could pull up on its individual components, and some modern gear. In the end I think I have a good idea of how it works, but I’d certainly love to hear if there’s anyone out there who might have actually worked with hardware like this and could fill in any blanks.

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Retrotechtacular: Field Assembling Airplanes Like Wartime “Ikea”

December 21, 2017 by Tom Nardi 29 Comments

Imagine it’s 1943, and you have to transport 1,000 P-47 fighter planes from your factory in the United States to the front lines in Europe, roughly 5,000 miles over the open ocean. Flying them isn’t an option, the P-47 has a maximum range of only 1,800 miles, and the technology for air-to-air refueling of fighter planes is still a few years off. The Essex class aircraft carriers in use at this time could carry P-47s in a pinch, but the plane isn’t designed for carrier use and realistically you wouldn’t be able to fit many on anyway. So what does that leave?

It turns out, the easiest way is to simply ship them as freight. But you can’t exactly wrap a fighter plane up in brown paper and stick a stamp on it; the planes would need to be specially prepared and packed for their journey across the Atlantic. To get the P-47 inside of a reasonably shaped shipping crate, the wings, propeller, and tail had to come off and be put into a separate crate. But as any reader of Hackaday knows, getting something apart is rarely the problem, it’s getting the thing back together that’s usually the tricky part.

So begins the 1943 film “Uncrating and Assembly of the P-47 Thunderbolt Airplane“ which has been digitally restored and uploaded to YouTube by [Zeno’s Warbirds]. In this fascinating 40 minute video produced by the “Army Air Forces School of Applied Tactics”, the viewer is shown how the two crates containing the P-47 are to be unpacked and assembled into a ready-to-fly airplane with nothing more than manpower and standard mechanic’s tools. No cranes, no welders, not even a hanger: just a well-designed aircraft and wartime ingenuity.

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The German Space Program That Never Was

December 4, 2017 by Tom Nardi 89 Comments

A previous post discussed the creation of the V-2 rocket, the first man-made object to reach space. Designed and built at the Peenemünde Army Research Center during World War II, the V-2 was intended to be a weapon of mass destruction, but ended up being far more effective as a tool of discovery than it ever did on the battlefield. In fact, historians now estimate that more people died during the development and construction of the V-2 than did in the actual attacks carried out with it. But even though it failed to win the war for Germany, it still managed to change the world in another way: as it served as the basic blueprint for all subsequent rockets right up to modern-day vehicles.

But the V-2 wasn’t the only rocket-powered vehicle that the Germans were working on, a whole series of follow-up vehicles were in the design phase when the Allies took Berlin in 1945. Some were weapons, but not all. Pioneers like Walter Dornberger and Wernher von Braun saw that rocketry had more to offer mankind than a new way to deliver warheads to the enemy, and the team at Peenemünde had begun laying the groundwork for a series of rockets that could have put mankind into space years before the Soviets.

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Books You Should Read: V-2 By Walter Dornberger

November 3, 2017 by Tom Nardi 63 Comments

In an era where we can watch rockets land on their tails Buck Rogers-style live on YouTube, it’s difficult to imagine a time when even the most basic concepts of rocketry were hotly debated. At the time, many argued that the very concept of a liquid fueled rocket was impossible, and that any work towards designing practical rocket powered vehicles was a waste of time and money. Manned spacecraft, satellite communications, to say nothing of landing on other worlds; all considered nothing more than entertainment for children or particularly fanciful adults.

Walter Dornberger (Bundesarchiv, Bild 146-1980-009-33 / CC-BY-SA 3.0)

This is the world in which V-2, written by the head of the German rocket development program Walter Dornberger, takes place. The entire history of the A-4/V-2 rocket program is laid out in this book, from the very early days when Dornberger and his team were launching rockets with little more than matches, all the way up to Germany’s frantic attempts to mobilize the still incomplete V-2 rocket in face of increasingly certain defeat at the end of World War II.

For those fascinated with early space exploration and the development of the V-2 rocket like myself, this book is essentially unparalleled. It’s written completely in the first person, through Dornberger’s own eyes, and reads in most places like a personal tour of his rocket development site at the Peenemünde Army Research Center. Dornberger walks through the laboratories and factories of Peenemünde, describing the research being done and the engineers at work in a personal detail that you simply don’t get anywhere else.

But this book is not only a personal account of how the world’s first man-made object to reach space was created, it’s also a realistic case study of how engineers and the management that pays the bills often clash with disastrous results. Dornberger and his team wanted to create a vehicle to someday allow man to reach space, while the Nazi government had a much more nefarious and immediate goal. But this isn’t a book about the war — the only battles you’ll read about in V-2 take place in meeting rooms, where the engineers who understood the immense difficulty of their task tried in vain to explain why the timetables and production numbers the German military wanted simply couldn’t be met.

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Retrotechtacular: Hacking Wartime Mail

October 6, 2017 by Al Williams 33 Comments

I’m guessing you got quite a few e-mails today. But have you ever had a v-mail? That sounds like some new term for video e-mail, but it actually dates back to World War II. If you are in Europe, the term was Airgraph — not much more descriptive.

If you make a study of war, you’ll find one thing. Over the long term, the winning side is almost always the side that can keep their troops supplied. Many historians think World War II was not won by weapons but won by manufacturing capability. That might not be totally true, but supplies are critical to a combat force. Other factors like tactics, doctrine, training, and sheer will come into play as well.

On the other hand, morale on the front line and the home front is important, too. Few things boost morale as much as a positive letter from home. But there’s a problem.

While today’s warfighter might have access to a variety of options to communicate with those back home, in World War II, communications typically meant written letters. The problem is ships going from the United States to Europe needed to be full of materials and soldiers, not mailbags. With almost two million U.S. soldiers in the European Theater of Operations, handling mail from home was a major concern.

British Mail Hack

The British already figured out the mail problem in the 1930s. Eastman Kodak and Imperial Airways (which would later become British Airways) developed the Airgraph system to save weight on mail-carrying aircraft. Airgraph allowed people to write soldiers on a special form. The form was microfilmed and sent to the field. On the receiving end, the microfilm was printed and delivered as regular mail.

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3DP Enigma Keyboard Improves On The Original

August 12, 2017 by John Baichtal 1 Comment

[Asciimation], who previously created an Enigma Machine wristwatch, decided to go all-in and make a 3D-printed Enigma machine. Not a perfect replica, but rather an improved version that works the same but doesn’t concern itself with historical accuracy. For instance, the current step involves building the keyboard. Rather than trying to re-create the spring-and-pin method of the original, he simply swapped in readily available, double-throw micro switches.

This project has a tremendous amount of fascinating detail. [Asciimation] did his research and it shows; he downloaded blueprints of the original and used hacked digital calipers to precisely measure each rotor’s teeth, so that it could be re-created for printing. He even re-created the Enigma font to ensure that his printed rotor wheels would look right–though in doing so he discovered that the original machine used one typeface for the keyboard, one for the wheels, and one for the indicator lamps.

We previously published [Asciimation]’s Enigma machine wristwatch project, where he simulated the functionality of an Enigma with an Arduino.

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