helicopter

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Hackaday Links: October 9, 2022

October 9, 2022 by 16 Comments

Don’t you just hate it when you walk out of the bathroom with toilet paper stuck to your shoe? That’s a little bit like what happened when the Mars helicopter Ingenuity picked up a strange bit of debris on one of its landing pads. The foreign object was spotted on the helicopter’s down-pointing navigation camera, and looks for all the world like a streamer of toilet paper flopping around in the rotor wash. The copter eventually shed the debris, which wafted down to the Martian surface with no further incident, and without any apparent damage to the aircraft. NASA hasn’t said more about what the debris isn’t — aliens — than what it is, which of course is hard to say at this point. We’re going to go out on a limb and say it’s probably something we brought there, likely a scrap of plastic waste lost during the descent and landing phase of the mission. Or, you know, it’s getting to be close to Halloween, a time when the landscape gets magically festooned with toilet paper overnight. You never know.

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[Tom Stanton] Builds An Osprey

October 8, 2022 by 20 Comments

The V-22 Osprey is an aircraft like no other. The tiltrotor multirole military aircraft makes an impression wherever it goes; coincidentally, a flight of two of these beasts flew directly overhead yesterday and made a noise unlike anything we’ve ever heard before. It’s a complex aircraft that pushes the engineering envelope, so naturally [Tom Stanton] decided to build a flight-control accurate RC model of the Osprey for himself.

Sharp-eyed readers will no doubt note that [Tom] built an Osprey-like VTOL model recently to explore the basics of tiltrotor design. But his goal with this build is to go beyond the basics by replicating some of the control complexity of a full-scale Osprey, without breaking the bank. Instead of building or buying real swash plates to control the collective and cyclic pitch of the rotors, [Tom] used his “virtual swashplate” technique, which uses angled hinges and rapid changes in the angular momentum of the motors to achieve blade pitch control. The interesting part is that the same mechanism worked after adding a third blade to each rotor, to mimic the Osprey’s blades — we’d have thought this would throw the whole thing off balance. True, there were some resonance issues with the airframe, but [Tom] was able to overcome them and achieve something close to stable flight.

The video below is only the first part of his build series, but we suspect contains most of the interesting engineering bits. Still, we’re looking forward to seeing how the control mechanism evolves as the design process continues.

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Large Tip Driven Copter Turns Very Slowly

August 8, 2022 by 21 Comments

Picking propeller size for any aircraft, but especially VTOLs, it’s a tradeoff between size and RPM. You can either move a large volume of air slowly or a small volume of air quickly. Small and fast tend to be the most practical for many applications, but if you’re thinking outside the box like [amazingdiyprojects], you can build a massive propeller and make it fly at just one revolution per second. (Video, embedded below the break.)

One of the challenges of large propellers is their high torque requirements. To get around this, [amazingdiyprojects] drives the 5m diameter propeller from the tips using electric motors with propellers. The blades are simple welded aluminum frames covered with heat-shrunk packing tape, braced with wires for stiffness.

The flight controller, with its own battery, is prevented from spinning with the blades by counteracting the spin of a small DC motor. Each blade is equipped with a servo-driven control surface, which can give roll and pitch control by adjusting deflection based on the blade’s radial position.

[amazingdiyprojects] control setup is very creative but somewhat imprecise. Instead of trying to write a custom control scheme, he configured the old KK2.15HC flight controller for a hexacopter. Each control servo’s PWM signal routes through a commutator disc with six sectors, one for each motor of the virtual hexacopter. This means each of the servos switches between six different PWM channels throughout its rotation. To compensate for lag when switching between channels, [amazingdiyprojects] had to tune the offset of the commutator disc otherwise it would veer off in the wrong direction. After a second test flight session to tune the flight controller settings, control authority improved, although it is still very docile in terms of response.

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Hackaday Links: December 12, 2021

December 12, 2021 by 14 Comments

It looks as though the Mars Ingenuity flight team is starting to press the edge of the envelope a bit. The tiny rotorcraft, already 280-something sols into a mission that was only supposed to last for about 30 sols, is taking riskier flights than ever before, and things got particularly spicy during flight number 17 this past week. The flight was a simple up-over-and-down repositioning of the aircraft, but during the last few meters of descent at its landing zone, Ingenuity dipped behind a small hill and lost line-of-sight contact with Perseverance. Without the 900-MHz telemetry link to the rover, operators were initially unable to find out whether the chopper had stuck the landing, as it had on its previous 16 flights. Thankfully, Perseverance picked up a blip of data packets about 15 minutes after landing that indicated the helicopter’s battery was charging, which wouldn’t be possible if the craft were on its side. But that’s it as far as flight data, at least until they can do something about the LOS problem. Whether that involves another flight to pop up above the hill, or perhaps even repositioning the rover, remains to be decided.

Thinking up strong passwords that are memorable enough to type when they’re needed is never easy, and probably contributes more to the widespread use of “P@$$w0rD123” and the like than just about anything. But we got a tip on a method the musically inclined might find useful — generating passwords using music theory. It uses standard notation for chords to come up with a long, seemingly random set of characters, like “DMaj7|Fsus2|G#9”. It’s pretty brilliant, especially if you’ve got the musical skills to know what that would sound like when played — the rest of us can click here to find out. But since we can’t carry a tune in a bucket, we’ll just stick with the “correct horse battery staple” method.

Looks like you can only light so many roofs on fire before somebody starts to take an interest in what’s going on. At least that seems to be the case with Tesla, which is now under investigation by the US Security and Exchanges Commission for not keeping its shareholders and the public looped in on all those pesky solar array fires it was having back in the day. The investigation stems from a 2019 whistleblower complaint by engineer Steven Henkes, who claims he was fired by Tesla after pointing out that it really would be best not to light their customers’ buildings on fire with poorly installed solar arrays. It’s interesting that the current investigation has nothing to do with the engineering aspects of these fires, but rather the financial implications of disclosure. We discussed some of those problems before, which includes dodgy installation practices and seems to focus on improperly torqued MC4 connectors.

Staying with the Tesla theme, it looks like the Cybertruck is going to initially show up as a four-motor variant. The silly-looking vehicle is also supposed to sport four-wheel steering, which will apparently make it possible to drive diagonally. We’ve been behind the wheel for nearly four decades at this point and can count on no hands the number of times diagonal driving would have helped, and while there might be an edge case we haven’t bumped into yet, we suspect this is more about keeping up with the competition than truly driving innovation. It seems like if they were really serious about actually shipping a product, they’d work on the Cybertruck windshield wiper problem first.

And finally, as I’m sure you’re all aware by now, our longtime boss Mike Szczys is moving on to greener pastures. I have to say the news came as a bit of shock to me, since I’ve worked for Mike for over six years now. In that time, he has put me in the enviable position of having a boss I actually like, which has literally never happened to me before. I just thought I’d take the chance to say how much I appreciate him rolling the dice on me back in 2015 and giving me a chance to actually write for a living. Thanks, Mike, and best of luck with the new gig!

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Hackaday Links: October 3, 2021

October 3, 2021 by 9 Comments

It’s one thing to speculate about what’s happening with the Mars helicopter Ingenuity, but it’s another to get an insider’s view on recent flight problems. As we previously reported, Ingenuity is starting to face a significant challenge, as a seasonal atmospheric pressure drop on Mars threatens to make the already rarefied air too thin to generate useful lift. Mission controllers tested the chopper at higher rotor speeds, and while that worked, later attempts to fly using that higher speed resulted in an abort. The article, written by one of the NASA/JPL engineers, is a deep dive into the problem, which occurred when Ingenuity sensed excessive wiggle in two of the servos controlling the rotor swashplate. The thought is that accumulated wear in the servos and linkages might be causing the problem; after all, Ingenuity has made thirteen flights so far, greatly exceeding the five flights originally programmed for it. Here’s hoping they can adapt and keep the helicopter flying, but whatever they do, it’ll have to wait a few weeks until Mars completes its conjunction and pops back out from behind the Sun.

With all the attention understandably paid to the recent 20th anniversary of the 9/11 terror attacks, it’s easy to forget that barely a month after that day, a series of what appeared to be follow-on attacks started: the Anthrax Attacks. Members of Congress and media outlets were targeted via the mail with highly refined anthrax spores, leading to the deaths of five people, with dozens more injured and exposed to anthrax. IEEE Spectrum has an interesting article that goes into some of the technology that was rapidly deployed in an attempt to sanitize the mail, including electron beam and X-ray irradiation to kill any spores. The article also points out how this wasn’t the first time people were afraid of the mail; outbreaks of yellow fever in 1899 led to fumigation of the mail with sulfur, after perforating it with a wicked-looking paddle.

Attention PCB-design newbies — now’s your chance to learn the entire PCB design process from the ground up, with the guidance of industry professionals. TeachMePCB is back again this year, offering to teach you everything you need to know about properly laying out a PCB design in pretty much any EDA software you want. The course requires a two- to five-hour commitment every week for two months, after which you’ll have designed a PCB for a macropad using a Raspberry Pi Pico. The course facilitator is Mark Hughes from Royal Circuits, who did a great Hack Chat with us last year on PCB finishes. This seems like a great way to get up to speed on PCB design, so if you’re interested, act soon — 460 people are already signed up, and the deadline is October 10.

Some of us really love factory tours, no matter what the factory is making. All the better when the factory makes cool electronics stuff, and better still when it’s our friends at Adafruit showing us around their New York City digs. True, it’s a virtual tour, but it has pretty much become a virtual world over the last couple of years, and it’s still a great look inside the Adafruit factory. Hackaday got an in-person tour back in 2015, but we didn’t know their building used to be a Westinghouse radio factory. In fact, the whole area was once part of the famed “Radio Row” that every major city seemed to have from the 1920s to the 1960s. It’s good to get a look inside a real manufacturing operation, especially one that’s right in the heart of a city.

And finally, those with a fear of heights might want to avoid watching this fascinating film on the change-out of a TV transmitter antenna. The tower is over 1,500′ (450 m) tall, lofting an aging antenna over the flat Florida terrain. Most of the footage comes from body-mounted cameras on the riggers working the job, including the one very brave soul who climbed up the partially unbolted antenna to connect it to the Sikorsky S64 Skycrane helicopter. It’s a strange combination of a carefully planned and slowly executed ballet, punctuated by moments of frenetic activity and sheer terror. The mishap when releasing the load line after the new antenna was placed could easily have swept the whole rigging crew off the antenna, but luckily nobody was injured.

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Hackaday Links: September 19, 2021

September 19, 2021 by 12 Comments

Things might be getting a bit dicey out in Jezero crater for Ingenuity. The little helicopter that could is starting to have trouble dealing with the thinning Martian atmosphere, and may start pressing against its margin of safety for continued operation. Ingenuity was designed for five flights that would all take place around the time its mothership Perseverance touched down on Mars back in February, at which time the mean atmospheric pressure was at a seasonal high. Over the last few months, the density of the Martian atmosphere has decreased a wee bit, but when you’re starting with a plan for a pressure that’s only 1.4% of Earth’s soupy atmosphere, every little bit counts. The solution to keeping Ingenuity flying is simple: run the rotors faster. NASA has run a test on that, spinning the rotors up to 2,800 RPM, and Ingenuity handled the extra stresses and power draw well. A 14th flight is planned to see how well the rotors bite into the rarefied air, but Ingenuity’s days as a scout for Perseverance could be numbered.

If you thought privacy concerns and government backdoors into encryption technology were 21st-century problems, think again. IEEE Spectrum has a story about “The Scandalous History of the Last Rotor Cipher Machine,” and it’s a great read — almost like a Tom Clancy novel. The story will appeal to crypto — not cryptocurrency — fans, especially those fascinated by Enigma machines, because it revolves around a Swiss rotor cipher machine called the HX-63, which was essentially a refinement of the original Enigma technology. With the equivalent of 2,000-bit encryption, it was considered unbreakable, and it was offered for sale to any and all — at least until the US National Security Agency sprung into action to persuade the inventor, Boris Hagelin, to shelve the HX-63 project in favor of electronic encryption. The NSA naturally helped Hagelin design this next generation of crypto machines, which of course all had backdoors built into them. While the cloak and dagger aspects of the story — including a possible assassination of Boris Hagelin’s son in 1970, when it became clear he wouldn’t “play ball” as his father had — are intriguing, the peek inside the HX-63, with its Swiss engineering, is the real treat.

One of the great things about the internet is how easy it is to quickly answer completely meaningless questions. For me, that usually involves looking up the lyrics of a song I just heard and finding out that, no, Robert Plant didn’t sing “Whoopie Cat” during Misty Mountain Hop. But it also let me answer a simple question the other day: what’s the largest single-piece metal object ever created? I figured it would have to be a casting of some sort, and likely something from the middle of the previous century. But as it turns out, the largest casting ever appears to have been manufactured in Sheffield, England in 2015. The company, Sheffield Forgemaster International, produced eleven castings for the offshore oil industry, each weighing in at over 320 tonnes. The scale of each piece is mind-boggling, and the technology that went into making them would be really interesting to learn about. And it goes without saying that my search was far from exhaustive; if you know of a single-piece metal part larger than 320 tonnes, I’ll be glad to stand corrected.

Have you heard about “teledriving” yet? On the face of it, a remote-controlled car where a qualified driver sits in an office somewhere watching video feeds from the car makes little sense. But as you dig into the details, the idea of remotely piloted cars starts to look like one of those “Why didn’t I think of that?” ideas. The company behind this is called Vay, and the idea is to remotely drive a ride-share vehicle to its next customer. Basically, when you hail a ride, a remote driver connects to an available car and drives it to your location. You get in and take over the controls to drive to your destination. When you arrive, another remote drive pilots the car to its next pickup. There are obvious problems to work out, but the idea is really the tacit admission that all things considered, humans are way better at driving than machines are, at least right now.

Coaxcopter To Carry Man

September 3, 2021 by 14 Comments

One of the major perks of all the affordable flight controllers and motors available from the hobby market is that you can really experiment with some crazy aircraft designs. [amazingdiyprojects] is experimenting with a coaxial helicopter design, with the goal off possibly using for a manned version in the future. (Video link, embedded below.)

The aircraft uses a pair of coaxial counter-rotating motors with large propellers, with several redundant control surfaces below the propellers. One of the theoretical advantages of this arrangement, compared to the more conventional quadcopter type designs, is redundancy. While a quadcopter will start tumbling when a single motor fails, this design will still be able to descend safely with just one motor.

It is also not dependent on the main motors for yaw, pitch and roll control. In multirotors, the motors need to keep a significant amount of the motor’s available power in reserve to increase torque at a moment’s notice for attitude control. This craft can use all the available thrust from the motors for lift, since control is provided by the control surfaces. There are five sets of redundant control surfaces below the propellers, each set connected to a separate flight controller.

Another advantage of this design is efficient for a given footprint, since one large propeller will always be more efficient than multiple smaller propellers. One of the goals for [amazingdiyprojects] is to fit the full size craft in a shipping container or on a trailer for transport without dissasembly.

[amazingdiyprojects] has built manned drones before, using both electric motors and internal combustion engines. And don’t miss the most gonzo wind tunnel ever at 7:00 in the video below. Continue reading “Coaxcopter To Carry Man” →