Rocket Roll Control, The Old Fashioned Way

November 4, 2025 by Lewin Day 14 Comments

The vast majority of model rockets go vaguely up and float vaguely downwards without a lot of control. However, [newaysfactory] built a few rockets that were altogether more precise in their flight, thanks to his efforts to master active roll control.

[newaysfactory] started this work a long time ago, well before Arduinos, ESP32s, and other highly capable microcontroller platforms were on the market. In an era when you had to very much roll your own gear from the ground up, he whipped up a rocket control system based around a Microchip PIC18F2553. He paired it with a L3G4200D gyro, an MPXH6115A barometer, and an MMA2202KEG accelerometer, chosen for its ability to provide useful readings under high G acceleration. He then explains how these sensor outputs were knitted together to keep a rocket flying straight and true under active control.

[newaysfactory] didn’t just master roll control for small rockets; he ended up leveraging this work into a real career working on fully-fledged autopilot systems. Sometimes your personal projects can take your career in interesting directions.

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100-Year Old Wagon Wheel Becomes Dynamometer

October 30, 2025 by Lewin Day 8 Comments

If you want to dyno test your tuner car, you can probably find a couple of good facilities in any nearby major city. If you want to do similar testing at a smaller scale, though, you might find it’s easier to build your own rig, like [Lou] did.

[Lou’s] dynamometer is every bit a DIY project, relying on a 100-year-old wagon wheel as the flywheel installed in a simple frame cobbled together from 6×6 timber beams. As you might imagine, a rusty old wagon wheel probably wouldn’t be in great condition, and that was entirely true here. [Lou] put in the work to balance it up with some added weights, before measuring its inertia with a simple falling weight test. The wheel is driven via a chain with a 7:1 gear reduction to avoid spinning it too quickly. Logging the data is a unit from BlackBoxDyno, which uses hall effect sensors to measure engine RPM and flywheel RPM. With this data and a simple calibration, it’s possible to calculate the torque and horsepower of a small engine hooked up to the flywheel.

Few of us are bench testing our lawnmowers for the ultimate performance, but if you are, a build like this could really come in handy. We’ve seen other dyno builds before, too. Video after the break.

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Self-Driving Cars And The Fight Over The Necessity Of Lidar

October 30, 2025 by Maya Posch 72 Comments

If you haven’t lived underneath a rock for the past decade or so, you will have seen a lot of arguing in the media by prominent figures and their respective fanbases about what the right sensor package is for autonomous vehicles, or ‘self-driving cars’ in popular parlance. As the task here is to effectively replicate what is achieved by the human Mark 1 eyeball and associated processing hardware in the evolutionary layers of patched-together wetware (‘human brain’), it might seem tempting to think that a bunch of modern RGB cameras and a zippy computer system could do the same vision task quite easily.

This is where reality throws a couple of curveballs. Although RGB cameras lack the evolutionary glitches like an inverted image sensor and a big dead spot where the optical nerve punches through said sensor layer, it turns out that the preprocessing performed in the retina, the processing in the visual cortex and analysis in the rest of the brain is really quite good at detecting objects, no doubt helped by millions of years of only those who managed to not get eaten by predators procreating in significant numbers.

Hence the solution of sticking something like a Lidar scanner on a car makes a lot of sense. Not only does this provide advanced details on one’s surroundings, but also isn’t bothered by rain and fog the way an RGB camera is. Having more and better quality information makes subsequent processing easier and more effective, or so it would seem.

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The Channel Crossing Bridge That Never Was

October 27, 2025 by Lewin Day 17 Comments

*Full marks for clarity of message. Credit: Euro Route materials*

When the Channel Tunnel opened in 1994, the undersea rail link saw Britain grew closer to the European mainland than ever before. However, had things gone a little differently, history might have taken a very different turn. Among the competing proposals for a fixed Channel crossing was a massive bridge. It was a scheme so audacious that fate would never allow it to come to fruition.

Forget the double handling involved in putting cars on trains and doing everything by rail. Instead, the aptly-named Euro Route proposed that motorists simply drive across the Channel, perhaps stopping for duty-free shopping in the middle of the sea along the way.

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Making A Cardboard Airplane Wing

October 24, 2025 by Fenix Guthrie 21 Comments

Ideally, an aircraft would be made of something reasonably strong, light, and weather resistant. Cardboard, is none of those things. But that did not stop [PeterSripol] from building an ultralight wing out of cardboard.

Firstly, he wanted to figure out the strongest orientation of the cardboard flutes for the wing spars. He decided on a mix of horizontal and vertical flutes for the wing spar, with the horizontal flutes resisting vertical deformations and the vertical flutes resisting chord wise deformations.

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Keep An Eye On Your Air-Cooled Engine

October 23, 2025 by Bryan Cockfield 24 Comments

There was a time, long ago, when passenger vehicles used to be much simpler than they are today. There were many downsides of this era, safety chief among them, but there were some perks as well. They were in general cheaper to own and maintain, and plenty could be worked on with simple tools. There’s perhaps no easier car to work on than an air-cooled Volkswagen, either, but for all its simplicity there are a number of modern features owners add to help them with these antiques. [Pegor] has created his own custom engine head temperature monitor for these vehicles.

As one could imagine with an air-cooled engine, keeping an eye on the engine temperature is critical to ensuring their longevity but the original designs omitted this feature. There are some off-the-shelf aftermarket solutions but this custom version has a few extra features that others don’t. It’s based on a ATMega32u4 microcontroller and will work with any K-type thermocouple, and thanks to its open nature can use a wide array of displays. [Pegor] chose one to blend in with the rest of the instrumentation on this classic VW. The largest issue that needed to be sorted out was around grounding, but a DC-DC converter created an isolated power supply for the microcontroller, allowing the thermocouple to be bonded to the grounded engine without disrupting operation of the microcontroller.

The finished product looks excellent and does indeed blend in to the dashboard more than the off-the-shelf temperature monitor that was in use before. The only thing that is planned for future versions is a way to automatically dim the display when the headlights are on, as [Pegor] finds it a little bright at night. We also enjoy seeing anything that helps these antiques stay on the road more reliably as their modern descendants don’t have any of the charm or engineering of these classics.

Was The Napier Nomad The Most Complex Aero Engine Ever Made?

October 18, 2025 by Dave Rowntree 11 Comments

From 1945 to 1955, a British aeronautical company called Napier & Son produced not just one but two versions of an intricate hybrid piston engine, which they named the Napier Nomad. The post-World War II era saw the development of several fascinating (and highly complex) piston-powered aeronautical engines alongside the emerging gas turbine engine designs. During this period, gas turbines were inefficient, unreliable, and primarily used for military applications. The (then) British Ministry of Supply commissioned the design and creation of a more fuel-efficient piston engine for aeronautical purposes, both military and civil, aiming to achieve gas turbine-like power while maintaining piston engine efficiency. Quite the challenge!

The specification aimed for 6000 hp and optimal fuel efficiency for long-range use. Napier knew gas turbines were limited by maximum operating temperature, constrained by available materials, which increased fuel consumption and reduced range. Piston engines operated at higher peak temperatures. They considered combining both principles to create a superior design, a concept suggested by aeronautical engineer Sir Harry Ricardo, who had consulted for Napier on other projects. Their complex solution was to build a gas turbine with a two-stroke diesel engine as the combustion chamber, merging the benefits of both.

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