Rebuilding an Extremely Rare Twin Mustang Fighter

Towards the end of the Second World War, as the United States considered their options for a possible invasion of Japan, there was demand for a new fighter that could escort long range bombers on missions which could see them travel more than 3,200 kilometers (2,000 miles) without refueling. In response, North American Aviation created the F-82, which essentially took two of their immensely successful P-51 fighters and combined them on the same wing. The resulting plane, of which only 272 were built, ultimately set the world record for longest nonstop flight of a propeller-driven fighter at 8,129 km (5,051 mi) and ended up being the last piston engine fighter ordered by the United States Air Force.

Today, only five of these “Twin Mustangs” are known to exist. One of those, a prototype XP-82 variant, is currently in the final stages of an epic decade-long rebuilding process directed by warbird restoration expert [Tom Reilly]. At the end of this painstaking restoration, which makes use of not only original hardware but many newly produced components built with modern technology such as CNC milling and 3D printing, the vintage fighter will become the only flyable F-82 in the world.

CNC milled replacement brake caliper

The project provides a fascinating look at what it takes to not only return a 70+ year old ultra-rare aircraft to fully functional status, but do it in a responsible and historically accurate way. With only four other intact F-82’s in the world, replacement parts are obviously an exceptional rarity. The original parts used to rebuild this particular aircraft were sourced from literally all over the planet, piece by piece, in a process that started before [Tom] even purchased the plane itself.

In a way, the search for parts was aided by the unusual nature of the F-82, which has the outward appearance of being two standard P-51 fighters, but in fact utilizes a vast number of modified components. [Tom] would keep an eye out for parts being sold on the open market which their owners mysteriously discovered wouldn’t fit on a standard P-51. In some cases these “defective” P-51 parts ended up being intended for the Twin Mustang project, and would get added to the collection of parts that would eventually go into the XP-82 restoration.

For the parts that [Tom] couldn’t find, modern manufacturing techniques were sometimes called in. The twin layout of the aircraft meant the team occasionally had one component but was missing its counterpart. In these cases, the original component could be carefully measured and then recreated with either a CNC mill or 3D printed to be used as a die for pressing the parts out of metal. In this way the team was able to reap the benefits of modern production methods while still maintaining historical accuracy; important on an aircraft where even the colors of the wires used in the original electrical system have been researched and faithfully recreated.

We’ve seen plenty of restorations here at Hackaday, but they tend to be of the vintage computer and occasionally Power Wheels variety. It’s interesting to see that the same sort of techniques we apply to our small scale projects are used by the pros to preserve pieces of history for future generations.

[Thanks to Daniel for the tip.]

Yet Another Restomod Of The Greatest Computer Ever

The best computer ever made is nearly thirty years old. The Macintosh SE/30 was the highest-spec original all-in-one Macs, and it had the power of a workstation. It had expansion slots, and you could hang a color monitor off the back. It ran Unix. As such, it’s become the prize of any vintage computer collector, and [Kris] recently completed a restomod on our beige king. It’s a restored Macintosh SE/30, because yes, we need to see more of these.

The restoration began with the case, which over the last thirty years had turned into an orange bromiated mess. This was fixed with RestOBrite, or Retr0Brite, or whatever we’re calling it now. This was just Oxyclean and an off-the-shelf bottle of 3% hydrogen peroxide, left out in the sun for a little bit.

Of course the capacitors had spilled their magic blue smoke over the last three decades, so a few replacements were in order. This is well-trodden territory, but [Kris] also had to replace the SCSI controller chip. Three of the pads for this chip had lifted, but this too is something that can be fixed.

With the restoration work complete, [Kris] turned his attention to doing something with this computer. The spinny hard drive was replaced with a SCSI2SD, currently the best solution to putting SCSI disks into old computers. There are a few more additions, including a Micron Xceed color video adapter, a video card that allows the SE/30 to drive two monitors (internal included) in color.

The current plans are to attach a modem to this SE/30, have it ring into a Raspberry Pi, and surf the web over a very slow connection. There is another option, though: You can get a WiFi adapter for the SE/30, and there’s a System 7 extension to make it work. Yes, we’re living in the future, in the past. It’s awesome.

Restoring An Apollo Guidance Computer

The Apollo Guidance Computer is a remarkably important piece of computing history. It’s the computer that guided the Apollo lander to land on the moon. We’ve seen a few replica builds over the years, but [CuriousMarc] got a closer look at one of the real things. In this video, [Marc] gets a look inside as his colleagues take apart one of the original AGCs and get a closer look at the insides of this piece of computer history.  Continue reading “Restoring An Apollo Guidance Computer”

Ants, Dirt, Rain, And The Commodore 64 That Wouldn’t Quit

Some electronics gear is built for the roughest conditions. With rugged steel cases, weatherproof gaskets, and cables passing through sealed glands, these machines are built to take the worst that Mother Nature can throw at them, shrugging off dust, mud, rain, and ice. Consumer-grade computers from the start of the home PC era, however, are decidedly not such machines.

Built to a price point and liable to succumb to a spilled Mountain Dew, few machines from that era that received any kind of abuse lived to tell the tale. Not so this plucky Commodore 64C, which survived decades exposed to the elements. As [Adrian Black] relates in the video below, this machine was on a scrap heap in an Oregon field, piled there along with other goodies by one of those “pickers” that reality TV loves so much. The machine was a disaster. It hadn’t been soaked in oil, but it was loaded with pine needles and an ant colony. The worst part, though, was the rust. The RF shielding had corroded into powder in some places, leaving reddish rust stains all over the place. Undeterred, [Adrian] gave the machine a good bath, first in water, then in isopropanol. Liberal applications of Deoxit helped with header connections, enough to see that the machine miraculously booted. It took some finagling, especially with the 6526 I/O controller, but [Adrian] was eventually able to get everything on the motherboard working, even the sound chip.

Whether this machine survived due to good engineering or good luck is debatable, but it’s a treat to see it come back to life. We hope a full restoration is in the works, not least as a way to make up for the decades of neglect.

Continue reading “Ants, Dirt, Rain, And The Commodore 64 That Wouldn’t Quit”

A Switching Power Supply, 1940s-Style

“They don’t build ’em like they used to.” There’s plenty of truth to that old saw, especially when a switch-mode power supply from the 1940s still works with its original parts. But when said power supply is about the size of a smallish toddler and twice as heavy, building them like the old days isn’t everything it’s cracked up to be.

The power supply that [Ken Shirriff] dives into comes from an ongoing restoration of a vintage teletype we covered recently. In that post we noted the “mysterious blue glow” of the tubes in the power supply, which [Ken] decided to look into further. The tubes are Thyratrons, which can’t really be classified as vacuum tubes since they’re filled with various gasses. Thyratrons are tubes that use ionized gas – mercury vapor in this case – to conduct large currents. In this circuit, the Thyratrons are used as half-wave rectifiers that can be rapidly switched on and off by a feedback circuit. That keeps the output voltage fixed at the nominal 140V DC required by the teletype, with a surprisingly small amount of ripple. The video below is from a series on the entire restoration; this one is cued to where the power supply is powered up for the first time. It’s interesting to see the Thyratrons being switched at about 120 Hz when the supply is under load.

Cheers to [Ken] and his retrocomputing colleagues for keeping the old iron running. Whether the target of his ministrations is a 1974 scientific calculator or core memory from an IBM 1401, we always enjoy watching him work.

Continue reading “A Switching Power Supply, 1940s-Style”

Restoring A 100 Year Old Vice To Pristine Condition

We love our vices. They hold pipes for us to saw away at, wood while we carve, and circuit boards so that we can solder on components. So we keep them in shape by cleaning and greasing them every now and then, [MakeEverything] went even further. He found a 100-year-old vice that was in very rough shape and which was going to be thrown out and did a beautiful restoration job on it.

It was actually worse than in rough shape. At some point, one of the jaws had been replaced by welding on a piece of rebar where the jaw would normally go. So he made entirely new jaws from solid brass as well as the pins to hold them firmly in place. We applaud his attention to detail. After removing all the old paint and corrosion, he painted it with a “hammered” spray paint to give it a nice hammered look. Though when he made the raised letters stand out by applying gold paint to them using an oil-based paint marker, we felt that was just showing off. The result is almost too gorgeous to use, but he assures us he will use it. You can see his process, as well as have a good look at the newly revived vice in the video below.

Continue reading “Restoring A 100 Year Old Vice To Pristine Condition”

Ancient Teletype Revived in Labor of Retrocomputing Love

Readers with not too many years under their belts may recall a time when the classic background sound effect for radio and television news programs included a staccato mechanical beat, presumably made by the bank of teletype machines somewhere in the studio, clattering out breaking stories onto rolls of yellow paper. It was certainly true that teletypes were an important part of the many communications networks that were strung together over the 20th century, but these noisy, greasy beasts had their day and are now largely museum pieces.

Which is exactly where the ancient Model 19 Teletype machine that [CuriousMarc] and company are restoring is destined. Their ongoing video series, six parts long as of this writing, documents in painstaking detail how this unit worked and how they are bringing it back to its 1930s glory. Teletypes were made to work over telephone lines with very limited bandwidth, and the hacks that went into transmitting text messages with a simple 5-bit encoding scheme are fascinating. The series covers the physical restoration of the machine, obviously well-loved during its long service with the US Navy. Of particular interest is the massive power supply with its Thyratron tubes and their mysterious blue glow.

The whole series is worth a watch if you’re even slightly interested in retrocomputing. We’re particularly taken with the mechanical aspects of these machines, though, which have a lot in common with mechanical calculators. [Al Williams] recently covered the non-replacement of the power supply caps for this unit, which is an interesting detour to this restoration.

Continue reading “Ancient Teletype Revived in Labor of Retrocomputing Love”