Pitting A CFD-Optimized Toroidal Propeller Against A Conventional One

September 28, 2026 by No comments

Although we often think that we got certain aspects of aerodynamics pretty much licked at this point, details like the optimal shape of a propeller remains hotly debated, both in- and outside of academia. This also includes wilder designs like toroidal propellers that even after more than a hundred years are still mostly just being evaluated. Recently [Neuronautics] took a shot at figuring out whether toroidal propellers even make sense.

In order to do this, first an efficiency baseline was established using a conventional and highly optimized propeller. After scanning it in to get its exact geometry and running it through a computational fluid dynamics (CFD) simulation, the software spat out a number of about 73%.

This left figuring out an optimized shape for the toroidal propeller to pit against it. While you can absolutely brute-force the seventeen shape parameters being considered here and test them in CFD, this would take insanely long. The hack here is to use multiple reference frame (MRF) to drastically speed up the selection process, though even then it still took two months. An example of using MRF with regular propellers is discussed  in a 2019 paper by [Randi Franzke] et al. in Energies.

Although MRF saves a lot of simulation time, you still end up with a lot of data that has to be analyzed for interesting patterns. For this [Neuronautics] trained a artificial neural network to automate filtering the many options for the most optimal ones, until converging onto a single design.

This G1401 design was the lucky winner, though with only a simulated 62.9% efficiency. Subsequently the one aspect that had been left unchanged was also iterated through, in the form of many different airfoil shapes until the final design appeared.

This design was then 3D printed in resin, which showed the first hurdle with the selection process, in that the printed versions were too thin and flexible to be usable as propellers. Cue many hours of manual tweaking of the design to make it actually printable.

Although the final design didn’t exceed 62% efficiency in a final test, the comment section to the video rightfully points out that the comparison was between a commercially made propeller and a DIY resin-printed one, which adds a whole other batch of variables. That said, it’s unlikely that there’d have been an obvious improvement either way, otherwise we’d already have seen toroidal propellers pop up everywhere on drones and aircraft.

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Two-Dimensional Material Now Easier To Manufacture

September 28, 2026 by 1 Comment

We often see scientific breakthroughs in journals or other media that’s reported on as if it’s a revolutionary technology guaranteed to reshape human existence, only to never hear about it again. A more cynical reason for this phenomenon is a certain amount of clickbait or engagement farming, but the real culprit often tends to be the discovery of a process that can’t produce the new material or effect at a scale that makes sense for mass production. One of those are MXenes (“max-enes”), a two-dimensional material first produced over a decade ago, but new research into them has developed a much more efficient way of producing them.

Before this discovery, these materials were produced in a convoluted process involving the MXene precursor materials, combining them with an etchant, washing them off, and then repeatedly spinning them in a centrifuge to separate out unwanted byproducts. As one can imagine, this doesn’t produce material in an industrial quantity. But the new method uses a vapor deposition process which simplifies the precursor steps using less expensive materials, as well as skips the etching step. After that, the researchers have found that the MXenes can grow in a much more controlled way, allowing for greater production amounts and higher quality.

In the intervening years since their discovery and first synthesis MXenes have shown potential for wide-ranging applications, from battery production to antennas to water purification. Another interesting application is as a switchable Faraday cage, as we’ve covered in the past. Hopefully the slow plod of scientific discovery continues and we can start seeing more of these incremental gains improving our lives, even if we don’t get a sudden technological revolution from it.

a beauty shot of the 3D-printed version

This PICO-8 Handheld Is No Fantasy

September 28, 2026 by 2 Comments

The PICO-8 is what is known as a ‘fantasy console’– you can program it, and there are oodles of games, but it’s not actually the 8-bit console it pretends to be. It’s a virtual machine, one that can run on top of any modern OS. When [UncleStem] got into PICO-8, he decided that he liked the PICO-8’s portability, he wanted a different kind of portability– so he took the ‘fantasy’ out of ‘fantasy console’ with his GameBoy-esqe handheld build, the build/dev video of which is embedded below.

At its core, it’s a Raspberry Pi Zero2W. That’s rather overkill for an 8-bit virtual machine, but it’s what he had on hand, and it makes for an easy build. The real hero of the build is the 720 by 720 pixel IPS display that matches the PICO-8’s square aspect ratio and takes up most of the real estate on the handheld. Even better, it has HDMI in and sound support, so with some buttons and a battery the hardware is all there after [UncleStem] designs a handsome 3D printed case, and also has a go milling it out of aluminum before giving up and having a pro do it.

Since it’s so easy to do these days, everything lives on a custom PCB from his sponsor that gives the handheld good mechanical stability. He’s also using the full-colour silkscreen option to make a very pretty PCB. If that part of the project appeals, we’ve covered guides to PCB art before. He’s shared the PCB and everything else he can on a google drive, though note that the fantasy console itself is not open source, and would need purchased to finish the project.

Oddly enough, this is not the first handheld we’ve seen based on the PICO-8. That would be this project that uses a single-button camcorder form-factor. As unique as that is, this project has the benefit of working with the whole library of PICO-8 games.

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A drone is shown, carrying underneath it a white plastic box. On the side of the box are two patch antennas. A camera extends from one end of the box, and a large GPS antenna from the other end.

Synthetic Aperture Radar Drone Gets Interferometric Imaging

September 28, 2026 by 5 Comments

It’s been more than a year since [Henrik Forstén] built the first iteration of his synthetic-aperture radar (SAR) imaging drone, and he’s certainly been productive in the meantime. Not only did he develop a much more powerful autofocus algorithm to clean up the radar images, but he also extended the software to create high-resolution interferometric images.

The main limitation of the original radar system was the GPS, which only had a resolution of about one meter; the autofocus algorithm owed much of its improved clarity to an improved estimation of the drone’s position. A simpler, though more expensive, solution was to add an RTK-capable GPS receiver. RTK (Real-Time Kinematic) receivers use a fixed ground station to constantly transmit a correction signal, letting them reach a couple centimeters of accuracy. Since the drone doesn’t actually need to know its position in real time, it can also use PPK (Post-Processing Kinematic) positioning, which compares recorded GPS signals after the flight to obtain similarly accurate positions.

[Henrik] also implemented a few other hardware improvements, including stabilizing the phase-locked loop used to generate the radar’s frequency sweep. The controller FPGA’s SD card interface had too low a bandwidth to record data in real time, so [Henrik] also implemented a simple, fast compression algorithm to speed that up. Most significantly, he also developed a program for interferometric imaging. The drone flies the same path twice at different altitudes; by comparing phase information from different passes, it’s possible to detect a target’s elevation. Normally, the radar program assumes constant elevation, making tall objects seem to lean toward the radar source; an interferogram, on the other hand, allowed [Henrik] to generate a detailed elevation map.

[Henrik] is no stranger to synthetic aperture radar; we’ve previously covered a bike-mounted iteration and a budget SAR system. If the concepts behind this are still a bit fuzzy, we’ve also covered a guide to making your own SAR setup.

Places To Visit: Landschaftspark Duisburg-Nord

September 28, 2026 by 12 Comments

There are many benefits to spending time in the park, but perhaps few of them have a Hackaday angle. There’s a park in Germany you might want to make an exception for, and it lies in the Ruhrpott city of Duisburg.

I was lucky enough last month to join a friend as she toured Germany for the first time with a caravan. It’s a large country with many beautiful places, so her choice might seem unexpected at first sight. The Ruhrpott, or Ruhr area, is a loose conurbation of industrial cities that loosely follows the river Ruhr on its trip to the Rhine on the western edge of the country. It’s close to  deposits of coal and iron ore, so just like similar areas in other countries, it became a centre for heavy industry. Today that continues, but as you might expect it’s also dotted with the remains of former industries. It’s one of those which is our subject for today, and it offers a very unusual opportunity.

A view out over a wooded post industrial landscape against a grey cloudy sky. In the foreground is a hiuge traverser crane.
Looking out over the former ore bunkers shows just how huge this site is.

Landschaftspark Duisburg-Nord is a forest park on the northern side of the city of Duisburg. But of course that’s not the whole story, because until 1985 it was the site of the Thyssen ironworks. In rehabilitating the site they chose to keep the main structures of the ironworks intact as they reclaimed the surrounding polluted industrial land, so today it may be one of the few places in the world where you can free of charge get up-close and personal with a fully-intact and preserved blast furnace. The site has three of them remaining along with their associated ore and gas processing plants, and the largest and newest, blast furnace number 5, is a structure you can climb to its top. If you’ve ever been curious about iron smelting, this is the place to come. Continue reading “Places To Visit: Landschaftspark Duisburg-Nord” →

Jet Megatextures Demo For ESP32-S3

September 28, 2026 by 4 Comments

Mipmapping is a good way to add a lot more detail to a 3D scene without overburdening the rendering hardware with detail that won’t be seen by the user. This level-of-detail rendering technique was demonstrated on the N64 console hardware a few years ago by [James Lambert] with [Michael Biggins], also known as [PhonicUK], now demonstrating it on the ESP32-S3 using his own Jet rendering engine.

Although level-of-detail rendering really speeds things up, it does also require far larger texture sizes, with [James]’s N64 demo taking up 40 MB of a 64 MB cartridge. To fit it on an ESP32-S3 with 16 MB of PSRAM and no SD card expansion or such the textures were further compressed to use 8-bit indexing, resulting in a mere 5.01 MB of textures.

There’s a demonstration video over on the associated Reddit thread, which shows the camera moving through the scene. Even if not as exciting as the Wipeout port by [Michael] that we previously covered, it does make clear that even without a proper 3D GPU the ESP32-S3 is already a pretty capable gaming machine that can go toe-to-toe with some 1990s consoles.

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The FPGA Chronicles: Exploring The Tang Nano 20K

September 28, 2026 by 20 Comments

FPGAs used to be mysterious, expensive devices, but these days you can buy surprisingly capable boards for very little money. Some years ago, I did an FPGA Bootcamp over on Hackaday.io. Much of that material still applies, but the hardware is dated. So I decided it was time to update it, using the inexpensive Tang Nano 20K and its GOWIN GW2AR-18 FPGA as the main platform, with perhaps a few excursions into other FPGAs.

History and Motivation

Once upon a time, if you wanted to have a custom IC, you went with a wheelbarrow full of money to a semiconductor company. However, some smart person at a semiconductor fab eventually realized they could make a chip with a lot of uncommitted blocks on it and then, for a custom chip, only design the wiring that connected them together. This still required a wheelbarrow full of money, but it was a smaller wheelbarrow.

Then one day, someone realized they could do the same thing but make the electrical connections between the blocks configurable. Maybe have fuses you can blow, or use EEPROM or RAM cells to remember which blocks are connected to which. It is complicated, sure, but then you can make many of these chips and sell them to people who could, in theory, make their own custom chips without your help.

When do you need an FPGA? A classic classroom exercise for an FPGA, for example, is a traffic light because it shows off how to do state machines, which are important for some kinds of FPGA designs. But other than as a learning example, why would you do this? Even a simple 8-bit CPU can handle a traffic light.

Suppose instead that you have hundreds of digital sensors on a rocket, and any one of them must raise an alarm within a few microseconds. A processor has to sample inputs in groups, service interrupts, or rely on extra hardware. An FPGA can simply implement the equivalent of one enormous OR gate. It watches every input continuously, and unrelated logic elsewhere in the FPGA does not steal execution time from it. Can you do it with a microcontroller? Probably, but not easily. For some classes of problems, an FPGA is the better answer.

Of course, you can also build a CPU on your FPGA and some FPGAs have CPUs in the same package. This is often a sweet spot because then things that are easy to do in software, you do in software. Things that are easier to do in hardware, you do in the FPGA.

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