Seeing airplanes fly in formation is an exciting experience at something like an air show, where demonstrations of a pilot’s skill and aircraft technology are on full display. But there are other reasons for aircraft to fly in formation as well. [Peter] has been exploring the idea that formation flight can also improve efficiency, and has been looking specifically at things like formation flight of UAVs or drones with this flight planning algorithm.
Aircraft flying in formation create vortices around the wing tips, which cause drag. However, another aircraft flying through those vortices will experience less drag and more efficient flight. This is the reason birds instinctively fly in formation as well. By planning paths for drones which will leave from different locations, meet up at some point to fly in a more efficient formation, and then split up close to their destinations, a significant amount of energy can potentially be saved. Continue reading “Formation Flying Does More Than Look Good”→
Liquid neural networks are inspired by biological neurons to implement algorithms that remain adaptable even after training. [Hasani] demonstrates a machine vision system that steers a car to perform lane keeping with the use of a liquid neural network. The system performs quite well using only 19 neurons, which is profoundly fewer than the typically large model intelligence systems we’ve come to expect. Furthermore, an attention map helps us visualize that the system seems to attend to particular aspects of the visual field quite similar to a human driver’s behavior.
The typical scaling law of neural networks suggests that accuracy is improved with larger models, which is to say, more neurons. Liquid neural networks may break this law to show that scale is not the whole story. A smaller model can be computed more efficiently. Also, a compact model can improve accountability since decision activity is more readily located within the network. Surprisingly though, liquid neural network performance can also improve generalization, robustness, and fairness.
A liquid neural network can implement synaptic weights using nonlinear probabilities instead of simple scalar values. The synaptic connections and response times can adapt based on sensory inputs to more flexibly react to perturbations in the natural environment.
[Christopher Helmke] is doing fantastic work in DIY systems for handling small hardware like fasteners, and that includes robotic placement of hardware into 3D prints. Usually this means dropping nuts into parts in mid-print so that the hardware is captive, but that’s not really the story here.
The really inventive part we want to highlight is the concept of reducing packaging and labor. Instead of including a zip-lock bag of a few bolts, how about embedding the bolts into a void in the 3D print, covered with a little snip-out retainer? Skip ahead to 1:54 in the video to see exactly what we mean. It’s a pretty compelling concept that we hope sparks a few ideas in others.
As clever as that concept is, the rest of the video is also worth a watch because [Christopher] shows off a DIY system that sits on top of his 3D printer and takes care of robotically placing the hardware in mid-print. He talks all about the challenges of such a system. It’s not perfect (yet), but seeing it in action is very cool.
The Wankel engine seems to pop up in surprising places every so often, only to disappear into the ether before someone ultimately resurrects it for a new application and swears to get it right this time. Ultimately they come across the same problems that other Wankels suffered from, namely poor fuel efficiency and issues with reliability. They do have a surprising power-to-weight ratio and a low parts count, though, which is why people keep returning to this well, although this time it seems like most of the problems might have been solved simply by turning the entire design inside out.
A traditional Wankel engine has a triangular-shaped rotor that rotates around a central shaft inside an oval-shaped housing. This creates three chambers which continually revolve around inside the engine as the rotor spins. The seals that separate the chambers are notoriously difficult to lubricate and maintain. Instead of using a rotor inside of a chamber, this design called the X-Engine essentially uses a chamber inside of a rotor, meaning that the combustion chamber and the seals stay in fixed locations instead of spinning around. This allows for much better lubrication of the engine and also much higher efficiency. By flipping the design on its head it is able to maintain a low moving parts count, high compression ratio, and small power-to-weight ratio all while improving reliability and performance and adding the ability to directly inject fuel rather than rely on carburetion or other less-ideal methods of fuel delivery that other Wankels require.
Astute internal combustion aficionados will note that this engine is still of a two-stroke design, and thus not likely to fully eliminate the emissions problems with Wankels in a way that is satisfactory to regulators of passenger vehicles. Instead, the company is focusing on military, commercial, and aerospace applications where weight is a key driver of design. We’ve seen time and time again how the Wankel fails to live up to its promises though, and we hope that finally someone has cracked the code on one that solves its key issues.
Hydroponic systems are an increasingly popular way to grow plants indoors using a minimum of resources. Even some commercial farming operations are coming online using hydroponic growing techniques, as these methods consume much less water, land area, and other resources than traditional agricultural methods. The downside is that the required lighting systems often take an incredible amount of energy. That’s why [ColdDayApril] set up a challenge to grow a plant hydroponically using no more than a single watt.
The system is set up to grow a single pepper plant in what is known as a deep-water culture, where the plant is suspended in a nutrient solution which has everything it needs to grow. The lightning system is based around the Samsung LM301B which comes close to the physical limits for converting electricity into white light and can manage around 220 lumens. A special power supply is needed for these low-power diodes, and the light is efficiently directed towards the plant using a purpose-built reflective housing. By placing this assembly very close to the plant and adjusting it as it grows, [ColdDayApril] was able to take the pepper plant from seed to flowering in 92 days.
It’s worth noting that the rest of the system uses a little bit of energy too. A two watt fan helps circulate some air in the hydroponic enclosure, and deep-water systems usually require an air pump to oxygenate the water which uses another two watts. This is still an impressive accomplishment as most hobbyist builds use lighting systems rated in the hundreds of watts and use orders of magnitude more energy. But, if you’re willing to add some fish into the system you can mitigate some of the energy requirements needed for managing the water system even further.
Sitting around a campfire or fireplace is an aesthetically pleasing experience in most situations, and can even provide some warmth. But unless you have a modern wood-burning appliance, it’s likely that most of the energy available in the biomass is escaping as un-burned vapors. Surprisingly, solving this problem is almost as easy as buying a can of beans at the store, and the result is a very efficient stove which can be used for heat in a pinch.
[Robert] is demonstrating this gasifier stove, not with beans but using both a can of peas and a larger can of potatoes. Various holes are drilled in each can in a specific pattern, and then the smaller pea can is fitted inside the larger potato can. Once a fire is going, the holes allow for air to flow in a way which traps the escaping un-burned vapors from the fuel and burns them as they flow through the contraption. No moving parts are required; this is all powered by the natural airflow that’s produced by the heat of the fire.
The result of a build like this is not only a stove which can extract a much higher percentage of the available fuel, but also quires much less fuel for a given amount of heat, and produces a much cleaner, less smokey fire. [Robert] also added a screen mantle which allows for this to be used more as a heat source, but similar builds can also be used just as effectively for cooking, too.
Drones are pretty common in the electoronics landscape today, and are more than just a fun hobby. They’ve enabled a wide array of realtors, YouTubers, surveyors, emergency responders, and other professionals to have an extremely powerful tool at their disposal. One downside to these tools is that the power consumption tends to be quite high. You can either stick larger batteries on them, or, as [Nicholas] demonstrates, just spin them really fast during flight.
We featured his first tests with this multi-modal drone flight style a while back, but here’s a quick summary: by attaching airfoils to the arms of each of the propellers and then spinning the entire drone, the power requirements for level flight can be dramatically reduced. This time, he’s back to demonstrate another benefit to this unique design, which is its ability to turn on its side and fly in level flight like an airplane. It’s a little bizarre to see it in the video, as it looks somewhat like a stationary propeller meandering around the sky, but the power requirements for this mode of flight are also dramatically reduced thanks to those wings on the arms.
There are a few downsides to this design, namely that the vertical wing only adds drag in level flight, so it’s not as efficient as some bi-wing designs, but it compromises for that loss with much more effective hover capabilities. He also plans to demonstrate the use of a camera during spin-hover mode as well in future builds. It’s an impressive experiment pushing the envelope of what a multi-rotor craft can do, and [Nicholas] still has plans to improve the design, especially when it comes to adding better control when it is in spin-hover mode. We’d expect plenty of other drones to pick up some of these efficiency gains too, except for perhaps this one.