Retrotechtacular: Using the Jet Stream for Aerial Warfare

Unmanned Aerial Vehicles (UAV) are all the rage these days. But while today’s combative UAV technology is as modern as possible, the idea itself is not a new one. Austria floated bomb-laden balloons at Venice in the middle 1800s. About a hundred years later during WWII, the Japanese used their new-found knowledge of the jet stream to send balloons to the US and Canada.

Each balloon took about four days to reach the western coast of North America. They carried both incendiary and anti-personnel devices as a payload, and included a self-destruct. On the “business end” of the balloons was the battery, the demolition block, and a box containing four aneroid barometers to monitor altitude. In order to keep the balloons within the 8,000 ft. vertical range of the jet stream, they were designed to drop ballast sandbags beginning one day into flight using a system of blow plugs and fuses. In theory, the balloon has made it to North American air space on day four with nothing left hanging but the incendiaries and the central anti-personnel payload.

Although the program was short-lived, the Japanese launched some 9,300 of these fire balloons between November 1944 and April 1945. Several of them didn’t make it to land. Others were shot down or landed in remote areas. Several made the journey just fine, and two even floated all the way to Michigan. Not bad for a rice paper gas bag.

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Retrotechtacular: The Bessemer Converter

Here’s a rose-colored look into the steelworks at Workington, Cumbria in northern England. At the time of filming in 1974, this plant had been manufacturing steel nonstop for 102 years using the Bessemer process. [Sir Henry Bessemer]’s method for turning pig iron into steel was a great boon to industry because it made production faster and more cost-effective.

hot ingotsMore importantly, [Bessemer]’s process resulted in steel that was ten times stronger than that made with the crucible-steel method. Basically, oxygen is blown through molten iron to burn out the impurities. The silicon and manganese burn first, adding more heat on top of what the oxygen brings. As the temperature rises to 1600°C, the converter gently rocks back and forth. From its mouth come showers of sparks and a flame that burns with an “eye-searing intensity”. Once the blow stage is complete, the steel is poured into ingot molds. The average ingot weighs four tons, although the largest mold holds six tons. The ingots are kept warm until they are made into rail.

The foreman explains that Workington Works would soon be switching over to a more modern process. As it was, Workington ran a pair of Bessemer converters on a 40-minute schedule, ensuring constant steel production from ore to rail. Between 1872 and 1974, these converters created an estimated 25 million metric tons of steel.

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Retrotechtacular: Wising Up with the SAGE System

The birth of the supersonic jet made the United States’ airstrike defenses look antiquated. And so, during the Cold War, the government contracted a number of institutions and vendors to create and maintain the Semi-Automatic Ground Environment (SAGE) aircraft detection system with Western Electric as project manager.

SAGE was developed at MIT’s Lincoln Laboratory on computers built by IBM. It used the AN/FSQ-7 in fact, which was The Largest Computer Ever Built. SAGE operated as a network of defense sectors that divided the continental U.S. and Canada. Each of these sectors contained a directional center, which was a four-story concrete blockhouse that protected and operated a ‘Q7 through its own dedicated power station. The SAGE computers employed hot standby processors for maximum uptime and would fail over to nearby direction centers when necessary.

Information is fed into each directional center from many radar sources on land, in the air, and at sea. The findings are evaluated on scopes in dimly-lit rooms on the front end and stored on magnetic cores on the back end. Unidentifiable aircraft traces processed in the air surveillance room of the directional center are sent to the ID room where they are judged for friendliness. If found unfriendly, they are sent to the weapons direction room for possible consequences.

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Retrotechtacular: Basic Telephony in the Field

Here is a great introduction to a practical application of electromagnetic theory—the field telephone. It’s a training film from 1961 that covers the sound-powered, local battery, and common battery systems along with the six basic components they use: generators, ringers, transmitters, receivers, induction coils, and capacitors.

Clear illustrations and smart narration are the hallmarks of these Army training films, and this one begins with a great explanation of generator theory. The phone’s ringer uses electromagnetic attraction and repulsion to do the mechanical work of striking the bells. Similarly, the sound waves generated by a caller’s speech move an armature to create an alternating electrical current that is transmitted and converted back to sound waves on the receiving end.

In the local battery system, the battery pushes pulsating DC to carry the voice transmission. An induction coil increases the capabilities of this system, but capacitors are required to filter out the frequencies that would overload the receiver, passing only the higher speech frequencies.

In order for several stations to communicate, the use of a switchboard is required to patch the calls through. There are many advantages of a common battery system with regard to call switching: no local battery is necessary, nor is a generator needed at each station. Calls are easier to place, and communication is much faster.

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Retrotechtacular: On the Wings of Goodyear

At the opposite end of the spectrum from the various blimp and rigid-hull airships Goodyear has created over the years stands the Goodyear Inflatoplane, the company’s foray into experimental inflatable aircraft. Goodyear had recently created a rubberized nylon material they called Airmat, the faces of which were connected internally by nylon threads. This material was originally developed during research into the viability of emergency airplane wings.

The United States military became interested in the Inflatoplane after Goodyear had performed successful testing of demonstration model GA-33. They believed that the Inflatoplane could be dropped from the air in a rigid container to facilitate an emergency rescue, or trucked around with the rest of the cargo as a last resort for just exactly the right situation. It seems like a good idea on paper. The Inflatoplane could stay packed into a fairly small container until it was needed. The GA-468 one-seater model could go almost 400 miles on 20 gallons of fuel, and required less pressure to inflate than the average car tire.

This episode of the Discovery Channel series WINGS includes a real-time demonstration of taking an Inflatoplane from crate to air set to late ’80s montage music. It takes the pilot a full five minutes to unfurl and  the plane, and he does it on a nice and level grassy spot by a lake that looks more like a cozy picnic spot than threatening enemy territory. While it’s better than not having an inflatable emergency aircraft, it just isn’t that practical.

Goodyear had all kinds of plans for future improvements, such as a vertical takeoff model and a rocket-powered version. But the Inflatoplane military initiative was grounded around the time that someone speaking for the Army deadpanned that they “could not find a valid military use for an aircraft that could be taken down by a well-aimed bow and arrow.”

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Retrotechtacular: The Early Days of CGI

We all know what Computer-Generated Imagery (CGI) is nowadays. It’s almost impossible to get away from it in any television show or movie. It’s gotten so good, that sometimes it can be difficult to tell the difference between the real world and the computer generated world when they are mixed together on-screen. Of course, it wasn’t always like this. This 1982 clip from BBC’s Tomorrow’s World shows what the wonders of CGI were capable of in a simpler time.

In the earliest days of CGI, digital computers weren’t even really a thing. [John Whitney] was an American animator and is widely considered to be the father of computer animation. In the 1940’s, he and his brother [James] started to experiment with what they called “abstract animation”. They pieced together old analog computers and servos to make their own devices that were capable of controlling the motion of lights and lit objects. While this process may be a far cry from the CGI of today, it is still animation performed by a computer. One of [Whitney’s] best known works is the opening title sequence to [Alfred Hitchcock’s] 1958 film, Vertigo.

Later, in 1973, Westworld become the very first feature film to feature CGI. The film was a science fiction western-thriller about amusement park robots that become evil. The studio wanted footage of the robot’s “computer vision” but they would need an expert to get the job done right. They ultimately hired [John Whitney’s] son, [John Whitney Jr] to lead the project. The process first required color separating each frame of the 70mm film because [John Jr] did not have a color scanner. He then used a computer to digitally modify each image to create what we would now recognize as a “pixelated” effect. The computer processing took approximately eight hours for every ten seconds of footage. Continue reading “Retrotechtacular: The Early Days of CGI”

Retrotechtacular: Crystals Go to War

More than one of our readers suggested we highlight this beautifully-shot process documentary about the laborious and precise manufacturing of piezoelectric quartz crystals in the early 1940s. Just a few years later, Bell Labs would perfect a method of growing synthetic crystals, sending droves of brave men and daintily-handed women from the Reeves Sound Laboratories to the unemployment line.

Early radio equipment relied upon tuned or L-C circuits for clocking. These were prone to drift by a few kHz, which prompted the use of crystal oscillators for stable frequencies in the 1920s. The lives of our armed forces and those of our WWII allies depended on reliable communication equipment, so the crystal oscillators they used were top shelf, produced by hand from Brazilian crust.

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