Preparing To Fire Up A 90-Year-Old Boiler After Half A Century

March 17, 2026 by Maya Posch 3 Comments

Continuing the restoration of the #1 Lancashire boiler at the Claymills Pumping Station in the UK, the volunteers are putting on the final touches after previously passing the boiler inspection. Although it may seem that things are basically ready to start laying down a fire after the boiler is proven to hold 120 PSI with all safeties fully operating, they first had to reassemble the surrounding brickwork, free up a seized damper shaft and give a lot of TLC to mechanisms that were brand new in the 1930s and last operated in 1971.

Removing the ashes from a Lancashire boiler. (Credit: Claymills pumping station, YouTube)

The damper shaft is part of the damper mechanism which controls doors that affect the burn rate, acting as a kind of throttle for the boilers. Unfortunately the shaft’s bearings had seized up completely, and no amount of heat and kinetic maintenance could loosen it up again. This forced them to pull it out and manufacture a replacement, but did provide a good look at how it’s put together. The original dial indicator was salvaged, along with some other bits that were still good.

Next was to fit the cast-iron ash boxes that sit below the boiler and from where ash can be scraped out and deposited into wheelbarrows. The automatic sprinkler stokers are fitted above these, with a good look at their mechanism. The operator is given a lot of control over how much coal is being fed into the boiler, as part of the early 20th-century automation.

The missing furnace doors on the #1 boiler were replaced with replicas based on the ones from the other boilers, and some piping around the boiler was refurbished. Even after all that work, it’ll still take a few weeks and a lot more work to fully reassemble the boiler, showing just how complex these systems are. With some luck it’ll fire right back up after fifty years of slumbering and decades of suffering the elements.

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Magnetic-Suspension Hoverboard Is Only 11 Years Late

March 15, 2026 by Tyler August 26 Comments

Anyone who saw Back to the Future II was disappointed when 2015 rolled around with nary a hoverboard in sight. There have been various attempts to fake it, but none of them quite have the feel of floating about wherever you’d like to go that the movie conveys. The little-known YouTuber [Colin Furze] has a new take on the idea: use magnets. Really big magnets.

If you’re one of [Colin]’s handful of subscribers, then you probably saw his magnetic-suspension bike. We passed on that one, but we couldn’t resist the urge to cover the hoverboard version, regardless of how popular [Colin] might be on YouTube. It’s actually stupidly simple: the suspension is provided by the repulsive force between alarmingly large neodymium magnets. In this case, two are on the base plate that holds the skateboard ‘trucks’, and two are on the wooden ‘deck’ that [Colin] rides upon.

Of course magnetic repulsion is a very unstable equilibrium, so [Colin] had to reduce the degrees of freedom. In his first test, that was with a pair of rods and linear bearings. That way the deck could only move in the z-axis, providing the sensation of hovering without allowing the deck to slide off its magnetic perch. Unfortunately those pins transferred too much vibration from the ground into the deck, ruining the illusion of floating on air.

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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” →

Pulse Jet Ski Chases The Winter Blues Away

March 8, 2026 by Tyler August 16 Comments

A long winter has a way of making a lot of us northerners a little bit squirrly. In [Build N Pulsejets]’s case, squirly enough to mount a home-made propane-powered pulse-jet to a kids’ kick scooter and take to the frozen lake for a rip.

Okay, well, it started as a kid’s scooter, but after trying it on the ice sans pulsejet, [Build N] decided that his cabin fever wasn’t quite bad enough to risk using it in stock configuration. Before mounting the 180 lb thrust (800 N) pulse jet he’d built in a previous video, a few modifications would be needed. Namely, a trio of scrap metal skis and a goodly amount of metalwork to mount them, and the pulse jet. Even on ice, with relatively little friction, the mass of maker and a full propane tank meant the acceleration wasn’t great, but he did get it over 44 mph (77 km/h) on the snowmobile drag strip. (Yeah, snowmobile drag racing’s a thing in the frozen north. Those of you sipping mai tais in the tropics are probably pretty jealous right now, huh?)

These pages have been no stranger to pulse jets, given that they’re probably the easiest engine to build at home. We’ve seen them mounted on everything from go karts, to Swedish snomobiles, and even tea kettles. Actually, we’ve seen two of those. No points for guessing what nation the tea kettle builds hail from.

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The Quarterhorse 2.1, looking fast even on the ground.

Quarterhorse Vs Blackbird: Hermeus’ Flight Puts Them One Step Closer To Record

March 7, 2026 by Tyler August 34 Comments

You’ve got to be ambitious to target a legend. If there’s one thing the folks at Hermeus Aerospace are, though, it’s ambitious: not only do they plan on their Quarterhorse unmanned aerial vehicle (UAV) to outfly the SR-71 blackbird, they’re hoping to do it in record time. They took one big step closer to that goal in March 2026, when Quarterhorse 2.1 took off for the first time from Spaceport America.

The F-16-sized prototype is actually the second first flight Hermeus can brag of in the past year– version one first flew in May 2025. They’re iterating fast. Version 2.1 is hoped to prove a key part of the engine design for v2.2, which is the plane Humerus hopes to use to break the SR-71’s air-breathing speed record of Mach 3.3 from 1976. They’re hoping the next prototype can actually hit mach 5, which would be amazing if they pulled it off. Of course when exactly v2.2 will fly will depend largely on how this current model does in its test envelope.

This Quarterhorse hasn’t yet broken the sound barrier, but it certainly will. With the same F100 engine as the F-15 and F-16 fighters, it’s got the thrust, and one look tells you it has the aerodynamics. Of course an F100 can’t fly at Mach 5 — not on its own — but the F100 isn’t purely stock. It’s actually a component in Hermeus’ Chimera engine, which combines the F100 with a pre-chiller to actively cool the incoming supersonic air so the engine doesn’t melt at high speeds, and a ramjet stage that bypasses the engine entirely. That would make the Chimera a turboramjet engine; starting with an old and well-known turbine stage seems like a good move and is arguably a hack.

It would work like this: the engine takes off on turbine, the chiller kicks in when the aircraft goes supersonic, and the turbine is bypassed completely at high mach. This is how they hope to break the SR-71’s record: as well-designed as the J-58 engine was in that plane, it only pushed bleed air into the afterburner, rather than bypassing its turbine stage entirely, so was limited by the need to not melt said turbines. In some ways, the Chimera reminds us of a cheaper, simpler SABER engine. Of course as ambitious as breaking a 50 year old speed record might be, Hermeus’ goals are downright humble compared to the single-stage-to-orbit dreams the SABRE was meant to allow.

It remains to be seen just how fast Quarterhorse 2.1 will be able to go. Notably, at least as it was first unveiled, the aircraft doesn’t have any kind of shock cone on the inlet. It’s unlikely that the pre-chiller makes that unnecessary; it is more likely that either 2.1 is going to be restricted to low mach numbers where such things aren’t necessary, or it will be fitted later. Either way, we look forward to following the test program, at least as much as it is made public. Check out footage from the test flight in the video embedded below.

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One Sailing Pulley To Rule Them All

March 6, 2026 by Bryan Cockfield 25 Comments

When thinking of humanity’s ability to harness wind energy, many people will conjure images of windmills from places like The Netherlands or Persia. But people have been using wind energy for far longer than that in the form of sailing ships. Using the wind for transportation goes back another four thousand years or so, but despite our vast experience navigating the seas with wind alone there is still some room for improvement. Many modern sailboats use a number of different pulleys to manage all of the rigging, but this new, open-source pulley can replace many of them.

The pulley, or “block” as they are sometimes called, is built with a polymer roller made out of a type of nylon, which has the benefit of being extremely durable and self-lubricating but is a bit expensive. Durability and lack of squeakiness is important in sailing applications, though. The body is made from CNC-machined aluminum and is composed of two parts, which pivot around the pulley’s axis to allow various ropes (or “lines”) to be inserted without freeing one end of the rope. In testing, this design outperformed some proprietary stainless steel pulleys of similar size.

Another perk of this design is that it can be set up to work in many different applications on a sailboat, whether that’s for hoisting a mainsail or pulling in a jib or any other task a pulley could be used for. It can also be stacked with others in many different configurations to build custom pulleys of almost any type, and can support up to 14 mm lines. For a sailor this could be extremely valuable, because as it stands each pulley on a ship tends to be used in only certain applications, and might also be proprietary from a specific company. This pulley is being released into the open-source world, allowing anyone to create them who wants one.

Thanks to [Keith] for the tip!

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Building A Heading Sensor Resistant To Magnetic Disturbances

March 6, 2026 by Lewin Day 10 Comments

Light aircraft often use a heading indicator as a way to know where they’re going. Retired instrumentation engineer [Don Welch] recreated a heading indicator of his own, using cheap off-the-shelf hardware to get the job done.

The heart of the build is a Teensy 4.0 microcontroller. It’s paired with a BNO085 inertial measurement unit (IMU), which combines a 3-axis gyro, 3-axis accelerometer, and 3-axis magnetometer into a single package. [Don] wanted to build a heading indicator that was immune to magnetic disturbances, so ignored the magnetometer readings entirely, using the rest of the IMU data instead.

Upon startup, the Teensy 4.0 initializes a small round TFT display, and draws the usual compass rose with North at the top of the display. Any motion after this will update the heading display accordingly, with [Don] noting the IMU has a fast update rate of 200 Hz for excellent motion tracking. The device does not self-calibrate to magnetic North; instead, an encoder can be used to calibrate the device to match a magnetic compass you have on hand. Or, you can just ensure it’s already facing North when you turn it on.

Thanks to the power of the Teensy 4.0 and the rapid updates of the BNO085, the display updates are nicely smooth and responsive. However, [Don] notes that it’s probably not quite an aircraft-spec build. We’ve featured some interesting investigations of just how much you can expect out of MEMS-based sensors like these before, too.

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