The “Tin Blimp” Was A Neither Tin Nor A Blimp: The Detroit ZMC-2 Story

March 10, 2026 by Tyler August 31 Comments

That fireball was LZ37. Nobody wanted to see repeats post-war.
Image: “The great exploit of lieutenant Warnefort 1916 England” by Gordon Crosby, public domain.

After all the crashing and burning of Imperial Germany’s Zeppelins in the later part of WWI – once the Brits managed to build interceptors that could hit their lofty altitude, and figured out the trick of using incendiary rounds to set off the hydrogen lift gas – there was a certain desire in airship circles to avoid fires. In the USA, that mostly took the form of replacing hydrogen with helium. Sure, it didn’t lift quite as well, but it also didn’t explode.

Still, supplies of helium were– and are– very much limited, and at least on a rigid Zeppelin, the hydrogen wasn’t even the most flammable part. As has become widely known, thanks in large part to the Mythbusters episode about the Hindenburg disaster, the doped cotton skin in use in those days was more flammable than some firestarters you can buy these days.

That’s a problem, because, as came up in the comments of our last airship article, rigid airships beat blimps largely on Rule of Cool. Who invented the blimp? Well, arguably it was Henri Griffard with his steam-driven balloon in 1857, but not many people have ever heard his name. Who invented the rigid airship? You know his name: Ferdinand Adolf Heinrich August Graf von Zeppelin. No relation. Probably. Well, admittedly most people don’t know the full name, but Count Zeppelin is still practically a household name over a century after his death. His invention was just that much cooler.

That unavoidable draw of coolness led to the Detroit Airship Company and their amazing tin blimp. The idea was the brainchild of a man named Ralph Upton, and is startling in its simplicity: why not take the all-metal, monocoque design that was just then being so successfully applied to heavier-than-air flight, and use it to build an airship? Continue reading “The “Tin Blimp” Was A Neither Tin Nor A Blimp: The Detroit ZMC-2 Story” →

What One-Winged Squids Can Teach The Airship Renaissance

February 25, 2026 by Tyler August 31 Comments

It’s a blustery January day outside Lakehurst, New Jersey. The East Coast of North America is experiencing its worst weather in decades, and all civilian aircraft have been grounded the past four days, from Florida to Maine. For the past two days, that order has included military aircraft, including those certified “all weather” – with one notable exception. A few miles offshore, rocking and bucking in the gales, a U.S. Navy airship braves the storm. Sleet pelts the plexiglass windscreen and ice sloughs off the gasbag in great sheets as the storm rages on, and churning airscrews keep the airship on station.

If you know history you might be a bit confused: the rigid airship USS Akron was lost off the coast of New Jersey, but in April, not January. Before jumping into the comments with your corrections, note the story I’ve begun is set not in 1933, but in 1957, a full generation later.

The airship caught in the storm is no experimental Zeppelin, but an N-class blimp, the workhorse of the cold-war fleet. Yes, there was a cold war fleet of airships; we’ll get to why further on. The most important distinction is that unlike the last flight of the Akron, this story doesn’t end in tragedy, but in triumph. Tasked to demonstrate their readiness, five blimps from Lakehurst’s Airship Airborne Early-Warning Squadron 1 remained on station with no gaps in coverage for the ten days from January 15th to 24th. The blimps were able to swap places, watch-on-watch, and provide continuous coverage, in spite of weather conditions that included 60 knot winds and grounded literally every other aircraft in existence at that time. Continue reading “What One-Winged Squids Can Teach The Airship Renaissance” →

Living In The (LLM) Past

February 9, 2026 by Al Williams 23 Comments

In the early days of AI, a common example program was the hexapawn game. This extremely simplified version of a chess program learned to play with your help. When the computer made a bad move, you’d punish it. However, people quickly realized they could punish good moves to ensure they always won against the computer. Large language models (LLMs) seem to know “everything,” but everything is whatever happens to be on the Internet, seahorse emojis and all. That got [Hayk Grigorian] thinking, so he built TimeCapsule LLM to have AI with only historical data.

Sure, you could tell a modern chatbot to pretend it was in, say, 1875 London and answer accordingly. However, you have to remember that chatbots are statistical in nature, so they could easily slip in modern knowledge. Since TimeCapsule only knows data from 1875 and earlier, it will be happy to tell you that travel to the moon is impossible, for example. If you ask a traditional LLM to roleplay, it will often hint at things you know to be true, but would not have been known by anyone of that particular time period.

Chatting with ChatGPT and telling it that it was a person living in Glasgow in 1200 limited its knowledge somewhat. Yet it was also able to hint about North America and the existence of the atom. Granted, the Norse apparently found North America around the year 1000, and Democritus wrote about indivisible matter in the fifth century. But that knowledge would not have been widespread among common people in the year 1200. Training on period texts would surely give a better representation of a historical person.

The model uses texts from 1800 to 1875 published in London. In total, there is about 90 GB of text files in the training corpus. Is this practical? There is academic interest in recreating period-accurate models to study history. Some also see it as a way to track both biases of the period and contrast them with biases found in data today. Of course, unlike the Internet, surviving documents from the 1800s are less likely to have trivialities in them, so it isn’t clear just how accurate a model like this would be for that sort of purpose.

Instead of reading the news, LLMs can write it. Just remember that the statistical nature of LLMs makes them easy to manipulate during training, too.

Featured Art: Royal Courts of Justice in London about 1870, Public Domain

The History Of Tandem Computers

January 26, 2026 by Al Williams 10 Comments

If you are interested in historical big computers, you probably think of IBM, with maybe a little thought of Sperry Rand or, if you go smaller, HP, DEC, and companies like Data General. But you may not have heard of Tandem Computers unless you have dealt with systems where downtime was unacceptable. Printing bills or payroll checks can afford some downtime while you reboot or replace a bad board. But if your computer services ATM machines, cash registers, or a factory, that’s another type of operation altogether. That was where Tandem computers made their mark, and [Asianometry] recounts their history in a recent video that you can watch below.

When IBM was king, your best bet for having a computer running nonstop was to have more than one computer. But that’s pricey. Computers might have some redundancy, but it is difficult to avoid single points of failure. For example, if you have two computers with a single network connection and a single disk drive. Then failures in the network connection or the disk drive will take the system down.

Continue reading “The History Of Tandem Computers” →

[Mark] shows off footage from a D1 master on the repaired deck

Reviving ReBoot With A Tape Deck Repair

January 4, 2026 by Tyler August 20 Comments

Do you remember ReBoot? If you were into early CGI, the name probably rings a bell, since when it premiered in 1994 it was the first fully computer-animated show on TV. Some time ago, a group found a pile of tapes from Mainframe Studios in Canada, the people behind ReBoot, and the computer historians amongst us were very excited… until they turned out to be digital broadcast master tapes. Exciting for fans of lost media, sure, but not quite the LTO backups of Mainframe’s SGI workstations some of us had hoped would turn up. Still, [Mark Westhaver], [Bryan Baker] and others at the “ReBoot Rewind” project have made great strides, to the point that in their latest update video they declare “We Saved ReBoot”

What does it take to revive a 30-year-old television project? Well, as stated, they started with the tapes. These aren’t ordinary VHS tapes: the Sony D-1 tapes, which were also known by the moniker “4:2:2”, are a format that most people who didn’t work in the TV or film industry will have never seen, and the tape decks are rare as hen’s teeth these days. Just getting a working one, and keeping it working, was one of the biggest challenges [Mark] and Reboot Rewind faced. In the end it took three somewhat-dodgy machines long past their service lives and a miraculously located spare read/write head to get a stable scanning rate.

The uncompressed digital output of these tapes isn’t something you can just burn to a DVD, either. The 720 × 576 resolution video stream is captured raw, but there are minor editing tweaks that need to be made in addition to tape errors that have cropped up over the years, and those need to be dealt with before the video and audio data gets encoded into a modern format. The video briefly glosses [Bryan Baker]’s workflow to do just that. At least they aren’t stuck with terrible USB video capture dongles VHS lovers have to deal with. Even if you don’t care about ReBoot, this isn’t the only show that was archived on D1 tapes so that workflow might be of interest to media fans.

We covered ReBoot Rewind when they were first searching for tape decks, so it’s great to have an update. Alas, the rights holders haven’t yet decided how exactly they’re going to release this fine footage, so if like this author you have fond memories of ReBoot, you may have to wait a bit longer for a reWatch.

Continue reading “Reviving ReBoot With A Tape Deck Repair” →

WWII Secret Agents For Science

November 14, 2025 by Al Williams 9 Comments

We always enjoy [History Guy]’s musing on all things history, but we especially like it when his historical stories intersect with technology. A good example was his recent video about a small secret group during the Second World War that deployed to the European Theater of Operations, carrying out secret missions. How is that technology related? The group was largely made of scientists. In particular, the team of nineteen consisted of a geographer and an engineer. Many of the others were either fluent in some language or had been through “spy” training at the secret Military Intelligence Training Center at Camp Ritchie, Maryland. Their mission: survey Europe.

Continue reading “WWII Secret Agents For Science” →

Batteries Not Included: Meet The Swiss Réglette!

October 21, 2025 by Dave Rowntree 4 Comments

Over on YouTube, [The Modern Rogue] created an interesting video showing a slide-rule-like encryption device called the Réglette. This was a hardware implementation of a Vigenère-like Cipher, technically referred to as a manual polyalphabetic substitution cipher. The device requires no batteries, is fully waterproof, daylight readable and easy to pack, making it really useful if you find yourself in a muddy trench in the middle of winter during a world war. Obviously, because it’s a slide rule.

Anyway, so how does this cipher work? Well, the ‘polyalphabetic’ bit infers the need for a key phrase, which is indeed the first thing all parties need to agree upon. Secondly, a number is required as a reference point. As you can see from the video, the sliding part of the device has letters of the alphabet, as well as numbers and a special symbol. The body has two series of numbers, with the same spacing as the central, sliding part. A second copy of the sliding part is also needed to slide in behind the first unit. This second copy is neatly stowed below the body during storage.

With each message letter, you lookup the corresponding cipher text number, then shift the slider to the next key phrase letter.

The cipher works by first aligning the starting letter of the (variable-length) key phrase with the reference number. Next, encode the first symbol from the cleartext message (the thing you want to encrypt). You simply look up the letter on the slide and read off either of the numbers next to it. Randomly selecting the left or right set adds an extra bit of strength to the code due to increased entropy. The number is the first symbol for your ciphertext (the thing you want to transmit to the receiver). Next, you move on to the next symbol in the cleartext message. Align the following letter of the key phrase with the reference number, look up the corresponding letter in the message, and transmit the following number onwards. When you run out of key phrase letters, you loop back to the start, and the cycle repeats.

The special symbol we mentioned earlier is not really a ‘blank’; it is a control symbol used to retransmit a new reference number with the existing setup. To change the reference number, the blank character is encoded and sent, followed by the latest reference number. When the blank symbol is received at the other end, the following code is used as the reference number, and the key phrase position is reset to point back to the first letter, restarting the cycle anew. Simple, yes. Effective? Well, not really by modern standards, but at the time of limited computing power (i.e. pen and paper, perhaps a mechanical calculator at best), it would have been sufficient for some uses for a couple of decades.

Why is this Vigenère-like? Well, an actual Vigenère cipher maps letters to other letters, but the Réglette uses numbers, randomly selected, adding entropy, as well as the control code to allow changing the cypher parameter mid-message. This makes it harder to attack; the original Vigenère was considered first-rate cryptography for centuries.

If you’d like to play along at home and learn some other simple ciphers, check this out. Kings and Queens of old frequently used cryptography, including the famous Queen Mary of Scots. Of course, we simply can’t close out an article on cryptography without mentioning the Enigma machine. Here’s one built out of Meccano!

Continue reading “Batteries Not Included: Meet The Swiss Réglette!” →