StratoSoar Glider Flies Itself From High Altitude

As the technology available to the average hacker and maker gets better and cheaper each year, projects which at one time might have only been within the reach of government agencies are inching closer to our grasp. Take for example the impressive work [Charlie Nicholson] has put into his StratoSoar series of autonomous gliders.

Dropped from several thousand feet by a high-altitude balloon, the glider’s avionics are designed to either guide it along a series of waypoints or head directly towards a specific target. Once at the given coordinates it can initiate different landing programs, such as spiraling down to the ground or releasing an onboard parachute. It’s an ambitious combination of custom hardware and software, made all the more impressive by the fact that it’s been put together by somebody who’s not yet old enough to have a driver’s license.

[Charlie] originally experimented with developing his own airframe using 3D printed components, but at least for now, found that a commercial off-the-shelf foam glider was a more practical option. All that’s required is to hollow out some areas to mount the servos, battery, and the avionics. This takes the form of a custom PCB that contains a ATSAMD21G18 microcontroller, an ICM-20948 inertial measurement unit (IMU), connections for GPS and LoRa modules, as well as several onboard sensors and some flash storage to hold collected data.

The goal of this open source project is to make these sort of unmanned aerial vehicles (UAVs) cheaper and more accessible for hobbyists and researchers. Eventually [Charlie] hopes to offer kits which will allow individuals to build and operate their own StratoSoar, making it even easier to get started. He’s currently working on the next iteration of the project that he’s calling StratoSoar MK3, but it hasn’t had a flight test yet.

We’ve seen various attempts to launch autonomous gliders from balloons in the past, but none from anyone as young as [Charlie]. We’re eager to see the StratoSoar project develop, and wish him luck in future test flights.

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Making An Aluminium Foil Glider To Prototype Hydroforming

Hydroforming is a very effective way to turn a ductile metal like aluminium or stainless steel into a specific shape, either using a die or by creating a closed envelope in which the hydraulic fluid is injected. While trying to think of ways to create a hydroformed airplane without spending big bucks on having it done professionally – or learning to weld sheet metal together with waterproof welds along the seams – [Adrian Perez] decided that using plain aluminium foil as found in the average kitchen might be a good way to get his feet wet here. When stuck together with double-sided tape, the foil is both strong and light enough to be inflated like a party balloon and still fly better than a lead balloon (which do fly, albeit poorly).

The basic design for the initial Luma glider that he assembled is based around a Kline-Fogleman (KA) airfoil. This type of airfoil is mostly characterized by the simplicity of construction, having been devised in the 1960s for paper airplanes. It uses a stepped approach rather than a continuous airfoil and has seen mostly attention in hobby circles. Even if this Luma glider brings to mind the ill-fated Goodyear Inflatoplane, a hydroformed version of these foil prototype gliders would not have to rely on being inflated to function.

For small-scale prototypes, using low-cost aluminium foil or similar to test out shapes before committing to a design to be welded and hydroformed does seem like a useful approach.

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The control panel of a glider winch

A Custom Radio And Telephone System For Glider Winch Operators

While gliding might be the most calm and peaceful way of moving through the air, launching a glider is a rather noisy and violent process. Although electric winches do exist, most airfields use big V8-powered machines to get their gliders airborne. [Peter Turczak] noticed that the winch operators at his airfield often had to juggle multiple communication channels while pressing buttons and moving levers, all with the deafening roar of a combustion engine right next to them. To make their life easier, he built a single communication device that combines multiple radio inputs and an analog telephone .

A stack of circuit boards next to an old phone ringer
The inside of the cabinet. Note the classic phone ringer

The main user interface is a sturdy headset that dampens engine noise significantly. This headset is connected to a cabinet that contains several modules connecting to different audio sources: an analog telephone line, an aircraft radio receiver, a PMR handheld radio, and even a music source in case the other lines are quiet. The system contains automatic switchover circuits based on a priority system, ensuring that important messages are never missed.

The electronic design is based on classic analog components like NE5532 and TL084 op amps, all mounted on small, custom-made PCBs. Audio transformers are used to avoid ground loops between the various signal sources while relays mute sources that are not prioritized. To ensure seamless compatibility with the telephone network, [Peter] used components from old desk phones, including line transformers, a DTMF keypad and even a mechanical ringer. His blog post is full of details that will be of interest to anyone working with op amps and audio, such as how to stabilize an amplifier that has significant wiring capacitance on its input.

At heart this whole project is “just” an audio mixer, although optimized for a very specific purpose. But designing even a simple mixer is by no means an easy task, as we reported a few years back. If you’re more into winches, you’ll be delighted to find that smaller ones can also be used for sledding and even wakeboarding.

Tiny Winged Circuits Fall With Style

Researchers at Northwestern University is moving the goalposts on how small you can make a tiny flying object down to 0.5 mm, effectively creating flying microchips. Although “falling with style” is probably a more accurate description.

A larger "IoT Macroflyer" with more conventional cicruitry
A larger “IoT Macroflyer” with more conventional circuitry

Like similar projects we featured before from the Singapore University of Technology and Design, these tiny gliders are inspired by the “helicopter seeds” produced by various tree species. They consist of a single shape memory polymer substrate, with circuitry consisting of silicon nanomembrane transistors and chromium/gold interconnects transferred onto it.

Looking at the research paper, it appears that the focus at this stage was mainly on the aerodynamics and manufacturing process, rather than creating functional circuitry. A larger “IoT Macroflyer” did include normal ICs, which charges a super capacitor from a set of photodiodes operating in the UV-A spectrum, which acts as a cumulative dosimeter. The results of which can be read via NFC after recovery.

As with other similar projects, the proposed use-cases include environmental monitoring and surveillance. Air-dropping a large quantity of these devices over the landscape would constitute a rather serious act of pollution, for which case the researchers have also created a biodegradable version. Although we regard these “airdropped sensor swarms” with a healthy amount of skepticism and trepidation, we suspect that they will probably be used at some point in the future. We just hope that those responsible would have considered all the possible consequences.

Mickey’s Big Timer Makes Glider Competitions Better

There’s plenty of obscure sports in the world. Many of them could benefit from bespoke equipment like scoring displays, but are too obscure to support commercial efforts in this regard. Radio controlled glider competitions fit into just this category. This led a man named [Mickey] to develop what he calls Mickey’s Big Timer, to aid in the running of such events.

Glider events run outdoors in full sunlight, so the system uses big bright LED matrix displays to show its timing information. The system, built around the STM32 Discovery platform, uses several of the microcontroller boards to drive several displays as well as the main controller which handles timing. It also packs in an audio system for issuing instructions to competitors. It can also display pilot names as well as instructions such as when competitors should land at the end of a heat.

Some code is available on Github for those interested in how it all works. Word around the RC forums has it that [Mickey] built several systems, some of which ended up as far afield as New Zealand where they helped run many successful glider contests over the years.

We’ve seen plenty of scoreboard projects over the years; a little portable one could be useful for adding some spice to your pickup neighbourhood games. Video after the break.

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Dynamic Soaring: 545 MPH RC Planes Have No Motor

The fastest remote-controlled airplane flight ever recorded took place in 2018, with a top speed of 545 miles/hour. That’s 877 km/h, or Mach 0.77!

What was the limiting factor, preventing the pilot-and-designer Spencer Lisenby’s plane from going any faster? The airstream over parts of the wing hitting the sound barrier, and the resulting mini sonic booms wreaking havoc on the aerodynamics. What kind of supercharged jet motor can propel a model plane faster than its wings can carry it? Absolutely none; the fastest RC planes are, surprisingly, gliders.

Dynamic soaring (DS) was first harnessed to propel model planes sometime in the mid 1990s. Since then, an informal international competition among pilots has pushed the state of the art further and further, and in just 20 years the top measured speed has more than tripled. But dynamic soaring is anything but new. Indeed, it’s been possible ever since there has been wind and slopes on the earth. Albatrosses, the long-distance champs of the animal kingdom, have been “DSing” forever, and we’ve known about it for a century.

DS is the highest-tech frontier in model flight, and is full of interesting physical phenomena and engineering challenges. Until now, the planes have all been piloted remotely by people, but reaching new high speeds might require the fast reaction times of onboard silicon, in addition to a new generation of aircraft designs. The “free” speed boost that gliders can get from dynamic soaring could extend the range of unmanned aerial vehicles, when the conditions are right. In short, DS is at a turning point, and things are just about to get very interesting. It’s time you got to know dynamic soaring.

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Dropping A Glider From 18,000 Feet

[Tarik and Kemal] have an objective in mind: to drop a home-made autonomous glider from a high-altitude balloon and safely return it to home. To motivate them, [Tarik] has decided not to cut his hair until they reach 18,000 feet. Given the ambition of their project, it isn’t surprising that his hair is getting rather long now.

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