Yamato-1: The World’s First Ship With Magnetohydrodynamic Propulsion

January 10, 2026 by Maya Posch 72 Comments

Although the humble propeller and its derivatives still form the primary propulsion method for ships, this doesn’t mean that alternative methods haven’t been tried. One of the more fascinating ones is the magnetohydrodynamic drive (MHDD), which uses the Lorentz force to propel a watercraft through the water. The somewhat conductive seawater is thus the working medium, with no moving parts required.

The end of the MHD thruster from the Yamato 1. It has six smaller green tubes surrounding a central circle. All of these pieces are coming through a grey metal fixture that is a circular shape. Small labels are affixed with Japanese writing on them. It is inside a sky blue metal frame. — The end of the MHD thruster from the *Yamato-1*.

Although simple in nature, only the Japanese Yamato-1 full-scale prototype ever carried humans in 1992. As covered in a recent video by [Sails and Salvos], the prototype spent most of its time languishing at the Kobe Maritime Museum, until it was scrapped in 2016.

There are two types of MHDD, based around either conduction – involving electrodes – or induction, which uses a magnetic field. The thrusters used by the Yamato-1 used the latter type of MHDD, involving liquid helium-cooled, super-conducting coils. The seawater with its ions from the dissolved salts responds to this field by accelerating according to the well-known right-hand rule, thus providing thrust.

The main flaw with an MHDD as used by the Yamato-1 is that it’s not very efficient, with a working efficiency of about 15%, and a top speed of about 15 km/h (8 knots). Although research in MHDDs hasn’t ceased yet, the elemental problem of seawater not really being that great as the fluid without e.g. adding more ions to it has meant that ships like the Yamato-1 are likely to remain an oddity like the Lun-class ekranoplan ground effect vehicle.

For as futuristic as this technology sounds, it’s suprisingly straightforward to build a magnetohydrodynamic drive of your own in the kitchen sink. Continue reading “Yamato-1: The World’s First Ship With Magnetohydrodynamic Propulsion” →

The Full-Sized 32-Wheeled, Articulated Bus Built For A 1976 Movie

January 8, 2026 by Maya Posch 70 Comments

Regardless of what your opinion is on cult-classic movies that got mixed-to-negative box office reviews when they were released, you have to admire the ones that went all out on practical effects and full-size constructions rather than CGI and scale models. Case in point the 1976 satirical comedy film The Big Bus that featured an absolutely massive articulated double-decker bus. With 32 wheels and multiple levels you’d think that a scale model would be used since most interior shots were done in the studio, but instead they built a real bus.

In this video by [Timeworn lengends] the genesis and details of the vehicle are covered. At the core of this road-worthy bus are two cabover International trucks, which were temporarily attached with a quick-release mechanism and required a second driver for the rear section who followed radio instructions for steering. In 1976 dollars, the entire bus prop cost between $250,000 and $500,000 USD to construct — making it one of the most expensive props ever made, especially considering the relatively low budget.

A fiberglass shell gave the bus its characteristic design, with the over the top ‘nuclear reactor’ propulsion befitting the comedy satire. Although the bowling alley and swimming pool were not really inside the bus, there was a functional bar installed along with the functional cockpit at the front.

Despite the movie flopping at the box office and critics being very mixed on its merits, it’s hard to deny that this bus prop is very unique and probably has a big part in why the movie has become a cult classic. As for the closest real-life equivalent, there is the articulated, double-decker Neoplan Jumbocruiser, which had its own troubled history.

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How Advanced Autopilots Make Airplanes Safer When Humans Go AWOL

January 6, 2026 by Maya Posch 21 Comments

It’s a cliché in movies that whenever an airplane’s pilots are incapacitated, some distraught crew member queries the self-loading freight if any of them know how to fly a plane. For small airplanes we picture a hapless passenger taking over the controls so that a heroic traffic controller can talk them through the landing procedure and save the day.

Back in reality, there have been zero cases of large airliners being controlled by passengers in this fashion, while it has happened a few times in small craft, but with variable results. And in each of these cases, another person in the two- to six-seater aircraft was present to take over from the pilot, which may not always be the case.

To provide a more reliable backup, a range of automated systems have been proposed and implemented. Recently, the Garmin Emergency Autoland system got its first real use: the Beechcraft B200 Super King Air landed safely with two conscious pilots on board, but they let the Autoland do it’s thing due to the “complexity” of the situation.

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Bicycle Tows 15,000 Pounds

January 4, 2026 by Bryan Cockfield 13 Comments

An old joke in physics is that of the “spherical cow”, poking fun at some of the assumptions physicists make when tackling a new problem. Making the problem simple like this can help make its fundamentals easier to understand, but when applying these assumptions to real-world problems these assumptions are quickly challenged. Which is what happened when [Seth] from Berm Peak attempted to tow a huge trailer with a bicycle — while in theory the bike just needs a big enough gear ratio he quickly found other problems with this setup that had to be solved.

[Seth] decided on a tandem bike for this build. Not only does the second rider add power, but the longer wheelbase makes it less likely that the tongue weight of the trailer will lift the front wheel off the ground. It was modified with a Class 3 trailer hitch, as well as a battery to activate the electric trailer brakes in case of an emergency. But after hooking the trailer up the first time the problems started cropping up. At such a high gear ratio the bike is very slow and hard to keep on a straight line. Some large, custom training wheels were added between the riders to keep it stable, but even then the huge weight still caused problems with the chain and even damaged the bike’s freehub at one point.

Eventually, though, [Berm Peak] was able to flat tow a Ford F-150 Lightning pulling a trailer a few yards up a hill, at least demonstrating this proof of concept. It might be the absolute most a bicycle can tow without help from an electric motor, although real-world applications for something like this are likely a bit limited. He’s been doing some other bicycle-based projects with more utility lately, including a few where he brings abandoned rental e-bikes back to life by removing proprietary components.

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Sleeping Rough In Alaska With A USPS Cargo Bike

January 4, 2026 by Tyler August 31 Comments

Out of all 49 beautiful US states (plus New Jersey), the one you’d probably least want to camp outside in during the winter is arguably Alaska. If you were to spend a night camping out in the Alaskan winter, your first choice of shelter almost certainly wouldn’t be a USPS electric cargo trike, but over on YouTube [Matt Spears] shows that it’s not that hard to make a lovely little camper out of the mail bike.

We’re not sure how much use these sorts of cargo trikes get in Alaska, but [Matt] seems to have acquired this one surplus after an entirely-predictable crash took one of the mirrors off. A delta configuration trike — single wheel in front — is tippy at the best of times, but the high center of gravity you’d get from a loading the rear with mail just makes it worse. That evidently did not deter the United States Postal Service, and it didn’t deter [Matt] either.

His conversion is rather minimal: to turn the cargo compartment into a camper, he only adds a few lights, a latch on the inside of the rear door, and a wood-burning stove for heat. Rather than have heavy insulation shrink the already-small cargo compartment, [Matt] opts to insulate himself with a pile of warm sleeping bags. Some zip-tie tire chains even let him get the bike moving (slowly) in a winter storm that he claims got his truck stuck.

While it might not be a practical winter vehicle, at least on un-plowed mountain roads, starting with an electric-assist cargo trike Uncle Sam already paid for represented a huge cost and time savings vs starting from scratch like this teardrop bike camper we featured a while back. While not as luxurious, it seems more practical for off-roading than another electric RV we’ve seen.

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Building A Steam Loco These Days Is Nothing But Hacks

January 1, 2026 by Tyler August 34 Comments

The Pennsylvania Railroad (PRR)’s T1 class is famous for many reasons: being enormous, being a duplex, possibly having beaten Mallard’s speed record while no one was looking… and being in production in the 21st century. That last fact is down to the redoubtable work by the PRR T1 Steam Locomotive Trust, who continued their efforts to reproduce an example of these remarkable and lamentably unpreserved locomotives in the year 2025.

They say that 2025 was “the year of the frame” because the frame was finally put together. We might say that for the PRR Trust, this was the year of welding. Back when the Baldwin and Altoona works were turning out the originals, the frames for steam locomotives were cast, not welded. There might not be anywhere on Earth to get a 64′ long (19.5 m), 71,000 lbs steel casting made these days. Building it up with welded steel might not be perfectly accurate, but it’s the sort of hack that’s needed to keep the project moving.

The cylinders, too, would have been bored-out castings back the day. Getting the four (it’s a duplex, remember) assemblies cast as one piece didn’t prove practical, so T1 #5550 will have welded cylinders as well. Given modern welding, we expect no problem with holding steam pressure. The parts are mostly machined and will be welded-together next year.

The giant wheels of the locomotive have been cast, but need to be machined. It’s not impossible to believe that locomotive #5550 will be on its frame, on its wheels, in 2026. The boiler is already done and the injectors to get water into it have been reinvented, which can perhaps be considered another hack.

Right now, if donations continue to trickle in at the current rate– and prices don’t rise any faster than they have been– the Trust hopes to have the locomotive steaming in 2030. She’s now 59.8% complete. That’s up from 40% when we last checked in, back in 2022, which is great progress considering this is a volunteer-driven, crowd-funded effort.

If you don’t have the skills or geographical location to volunteer with this build, but we’ve piqued your love of steam, perhaps you could 3D print an engine to scratch the itch.

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Modernizing A Classic Datsun Engine

December 30, 2025 by Bryan Cockfield 49 Comments

Although Nissan has been in the doldrums ever since getting purchased by Renault in the early 2000s, it once had a reputation as a car company that was always on the cutting edge of technology. Nissan was generally well ahead of its peers when bringing technologies like variable valve timing, turbocharging, fuel injection, and adjustable suspension to affordable, reliable vehicles meant for everyday use. Of course, a lot of this was done before computers were as powerful as they are today so [Ronald] set out to modernize some of these features on his 1978 Datsun 280Z.

Of course there are outright engine swaps that could bring a car like this up to semi-modern standards of power and efficiency, but he wanted to keep everything fully reversible in case he wants to revert to stock in the future, and didn’t want to do anything to the engine’s interior. The first thing was to remove the complicated mechanical system to control the throttle and replace it with an electronic throttle body with fly-by-wire system and a more powerful computer. The next step was removing the distributor-based ignition system in favor of individual coil packs and electronic ignition control, also managed by the new computer. This was perhaps the most complicated part of the build as it involved using a custom-made hall effect sensor on the original distributor shaft to tell the computer where the engine was in its rotation.

The final part of this engine modernization effort was upgrading the fuel delivery system. The original fuel injection system fired all of the injectors all the time, needlessly wasting fuel, but the new system only fires a specific cylinder when it needs fuel. This ended up improving gas mileage dramatically, and dyno tests also showed these modifications improved power significantly as well. Nissan hasn’t been completely whiffing since the Renault takeover, either. Their electric Leaf was the first mass-produced EV and is hugely popular in all kinds of projects like this build which uses a Leaf powertrain in a Nissan Frontier.

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