Patent Spat Leaves DJI Owing Textron $279M

Patents are the murky waters where technical jargon and legalese meet, and in this vast grey area of interpretation, DJI now owes Textron $279M.

At issue in the case were two patents issued to Textron (#8,014,909 and #9,162,752) regarding aircraft control systems for relative positioning to other vehicles and automatic hovering. The jury found that Textron’s intellectual property (IP) had been infringed and that damages amounted to $279M. DJI asserts that Textron’s patents are not valid and will appeal the decision. Appeals in patent trials are handled by the Federal Circuit and can be kicked up to the US Supreme Court, so don’t expect a final decision in the case anytime soon.

We’re not lawyers, so we won’t comment on the merits of the case, but, while it was a jury trial, it was one of many cases decided in the court of Judge Alan Albright, who has been the focus of scrutiny despite efforts to assign fewer cases to his docket amid wider efforts to stymie venue shopping in patent cases. Despite these efforts, the Western District of Texas is such a popular venue for patent cases that Berkeley offers a CEU on going to trial in Waco.

If you’re curious about more IP shenanigans, checkout the Honda mass takedown, the legality of making something similar, or why E3D patents some of their work.

German Air Force Surplus Teardown

It isn’t clear to us how [mrsylvain59] came into possession of a late-model piece of military gear from the German airforce, but we enjoyed watching the teardown below anyway. According to the documentation, the thing has a huge price tag, although we all know that the military usually pays top dollar for various reasons, so we are guessing the cost of the parts is quite a bit less than the price tag.

We don’t think [mrsylvain59] was sure what the amplifier (verstärker is German for amplifier) does. However, we recognized it as an avionics box from a UH-1 helicopter. We aren’t sure of its exact function, but it is classified under “Automatic Pilot Mechanisms and Airborne Gyro Components.”

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The Flight Of The Dremel

A few months ago we featured a model aircraft whose power plant came courtesy of an angle grinder. It was the work of [Peter Sripol], and it seems he was beseiged by suggestions afterwards that he might follow it up with a helicopter built using a Dremel rotary tool. Which he duly did, and the results can be seen in the video below the break.

The Dremel itself requires a gearing to drive the balsa-bladed rotor, and a tail rotor is mounted with its own motor at the end of a boom. The video has many entertaining failures which see him arrive at a set of balancing arms and a tailplane for stability. The result is a helicopter that flies after a fashion, and is even able to stay aloft for a few seconds rather than crashing to earth.

The machine lacks the full rotor pitch control of its commercial bretheren, indeed the only control is directional via the tail rotor. Still it deserves top marks for entertainment alone, and we wouldn’t mind a go ourselves. The original angle grinder craft can be seen here.

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Hackaday Links: October 9, 2022

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

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

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

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!