Fail of the Week: Two Rotors Are Not Better Than Four

Fair warning: [Paweł Spychalski]’s video is mostly him talking about how bad his “dualcopter” ended up. There are a few sequences of the ill-fated UAV undergoing flight tests, most of which seem to end with it doing a reasonable impression of a post-hole auger. We have to admit that it’s a pretty poor drone. But one can only truly fail if one fails to have some fun doing it, [Paweł] enjoyed considerable success, at least judging by the glee with which he repeatedly cratered the craft.

The overall idea seems to make sense, with coaxial props mounted in the middle of a circular 3D-printed frame. Mounted below the props are crossed vanes controlled by two servos. The vanes sit in the rotor wash and provide pitch and roll control, while yaw and thrust are controlled by varying the speeds of the counter-rotating props. [Paweł] knew going in that this was a sketchy aerodynamic design, and was surprised it performed as well as it did. But with ground effects limiting roll and pitch control close to the ground, the less-than-adequate thrust due to turbulence between the rotors, and the tendency for the center of mass and the center of gravity to get out whack with each other, all made for a joyously unstable and difficult to control aircraft.

Despite the poor performance, [Paweł] has plans for a Mark II dualrotor, a smaller craft with some changes based on what he learned. He’s no slouch at pushing the limits with multirotors, with 3D-printed racing quad frames and using LoRa for control beyond visual range. Still, we’re sure he’d appreciate constructive criticism in the comments, and we wish him luck with the next one.

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Laser-Powered Flying Machine Weighs Milligrams

We’ve become used to seeing some beautiful hand-made creations at the smaller end of the flying machine scale, tiny aircraft both fixed and rotary wing. An aircraft that weighs a few grams is entirely possible to build, such have been the incredible advances in component availability.

But how much smaller can a working aircraft be made? Given a suitable team and budget, how about into the milligrams? [Dr. Sawyer Fuller] and his team at the University of Washington have made an ornithopter which may be the lightest aircraft yet made, using a piezoelectric drive to flap flexible wings. That in itself isn’t entirely new, but whereas previous efforts had relied on a tether wire supplying electricity, the latest creation flies autonomously with its power supplied by laser to an on-board miniature solar cell that protrudes above the craft on its wires.

Frustratingly Dr. Fuller’s page on the machine is lighter on detail than we’d like, probably because they are saving the juicy stuff for a big reveal at a conference presentation. It is however an extremely interesting development from a technical perspective, as well as opening up an entirely new front in the applications for flying machines. Whatever happens, we’ll keep you posted.

You can see the craft in the video below the break, and if you’re interested lies with more conventional tiny machines take a look at the creator of a 2.9g Mustang model.

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Autonomous Spaceplane Travels to 10 km, Lands Safely 200 km Away

Space balloons, where one sends instrument packages to the edge of space on a weather balloon, are a low-cost way to scratch the space itch. But once you’ve logged the pressure and temperature and tracked your balloon, what’s the next challenge? How about releasing an autonomous glider and having it return itself to Earth safely?

That’s what [IzzyBrand] and his cohorts did, and we have to say we’re mightily impressed. The glider itself looks like nothing to write home about: in true Flite Test fashion, it’s just a flying wing made with foam core and Coroplast reinforced with duct tape. A pair of servo-controlled elevons lies on the trailing edge of the wings, while inside the fuselage are a Raspberry Pi and a Pixhawk flight controller along with a GPS receiver. Cameras point fore and aft, a pair of 5200 mAh batteries provide the juice, and handwarmers stuffed into the avionics bay prevent freezing.

After a long series of test releases from a quadcopter, flight day finally came. Winds aloft prevented a full 30-kilometer release, so the glider was set free at 10 kilometers. The glider then proceeded to a pre-programmed landing zone over 80 kilometers from the release point. At one point the winds were literally pushing the glider backward, but the little plane prevailed and eventually spiraled down to a perfect landing.

We’ve been covering space balloons for a while, but take a moment to consider the accomplishment presented here. On a shoestring budget, a team of amateurs hit a target the size of two soccer fields with an autonomous aircraft from a range of almost 200 kilometers. That’s why we’re impressed, and we can’t wait to see what they can do after a release from the edge of space.

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“Watch Dogs” Inspired Hacking Drone Takes Flight

They say that life imitates art, which in modern parlance basically means if you see something cool in a video game, movie or TV show, you might be inclined to try and build your own version. Naturally, such things generally come in the form of simple props, perhaps with the occasional embedded LED or noise making circuit. It’s not as if you can really build a phaser from Star Trek or a phone booth that’s bigger on the inside.

But after seeing the hacking quadcopter featured in the video game Watch Dogs 2, [Glytch] was inspired to start work on a real-world version. It doesn’t look much like the drone from the game, but that was never the point. The idea was to see how practical a small flying penetration testing platform is with current technology, and judging by the final build, we’d say he got his answer.

All the flight electronics are off the shelf quadcopter gear. It’s running on a Betaflight OMNIBUS F4 Pro V2 Flight controller with an M8N GPS mounted in the front and controlling the 2006 2400KV motors with a DYS F20A ESC. Interestingly [Glytch] is experimenting with using LG HG2 lithium-ion cells to power the quad rather than the more traditional lithium-polymer pack, though he does mention there are some issues with the voltage curve between the two battery technologies.

But the real star of the show is the payload: a Hak5 Pineapple Nano. As the Pineapple provides a turn-key penetration testing platform on its own, [Glytch] just needed a way to safely carry it and keep it powered. The custom frame keeps it snug, and the 5 Volt Battery Eliminator Circuit (BEC) on the DYS F20A ESC combined with a female USB port allows powering the Pineapple without having to make any hardware modifications.

We’ve seen quadcopters with digital weaponry before, though not nearly as many as you might think. But as even the toy grade quadcopters become increasingly capable, we imagine the airborne hacking revolution isn’t far away.

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Hands-On: Flying Drones with Scratch

I’ll admit it. I have a lot of drones. Sitting at my desk I can count no fewer than ten in various states of flight readiness. There are probably another half dozen in the garage. Some of them cost almost nothing. Some cost the better part of a thousand bucks. But I recently bought a drone for $100 that is both technically interesting and has great potential for motivating kids to learn about programming. The Tello is a small drone from a company you’ve never heard of (Ryze Tech), but it has DJI flight technology onboard and you can program it via an API. What’s more exciting for someone learning to program than using it to fly a quadcopter?

For $100, the Tello drone is a great little flyer. I’d go as far as saying it is the best $100 drone I’ve ever seen. Normally I don’t suggest getting a drone with no GPS since the price on those has come down. But the Tello optical sensor does a great job of keeping the craft stable as long as there is enough light for it to see. In addition, the optical sensor works indoors unlike GPS.

But if that was all there was to it, it probably wouldn’t warrant a Hackaday post. What piqued my interest was that you can program the thing using a PC. In particular, they use Scratch — the language built at MIT for young students. However, the API is usable from other languages with some work.

Information about the programming environment is rather sparse, so I dug in to find out how it all worked.

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RC Paper Airplane From Guts Of Quadcopter

Mini indoor drones have become an incredibly popular gift in the last few years since they’re both cool and inexpensive. For a while they’re great fun to fly around, until the inevitable collision with a wall, piece of furniture, or family member. Often not the most structurally sound of products, a slightly damaged quad can easily be confined to a cupboard for the rest of its life. But [Peter Sripol] has an idea for re-using the electronics from a mangled quad by building his own RC controlled paper aeroplane.

[Peter] uses the two rear motors from a mini quadcopter to provide the thrust for the aeroplane. The key is to remove the motors from the frame and mount them at 90 degrees to their original orientation so that they’re now facing forwards. This allows the drone’s gyro to remain facing upwards in its usual orientation, and keep the plane pointing forwards.

The reason this works is down to how drones yaw: because half of the motors spin the opposite direction to the other half, yaw is induced by increasing the speed of all motors spinning in one direction, mismatching the aerodynamic torques and rotating the drone. In the case of the mini quadcopter, each of the two rear motors spin in different directions. Therefore, when the paper plane begins to yaw off-centre, the flight controller increases power to the appropriate motor.

Mounting the flight controller and motors to the paper plane can either be achieved using a 3D-printed mount [Peter] created, or small piece of foam. Shown here is the foam design that mounts the propellers at wing level but the 3D printed version has then under the fuselage and flies a bit better.

Making paper planes too much effort? You could always use the one-stroke paper plane folder, or even the paper plane machine gun.

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Flite Test Puts a Chair in the Air

The Flite Test crew is well known for putting some crazy flying contraptions together. They’ve outdone themselves this time with a flying IKEA chair. This build began with [Josh] issuing a challenge to [Stefan]. Take a standard IKEA ladderback chair and make it fly– in less than six hours. With such a tight schedule, measuring twice and cutting once was right out the window. This was a hackathon-style “throw it together and hope it works” build.

The chair was plenty sturdy, so it became the core of the fuselage. [Stefan] grabbed the wing from a previous plane and placed it on the seat of the chair. Two carbon fiber rods drilled into the seat frame formed a tail boom. The tailfeathers were built from Flite Test foam – paper coated foam-core board.

With the structure complete, [Stefan] and his team added servos for control, a beefy motor for power, and some big LiPo batteries. The batteries hung from the bottom of the chair to keep the center of gravity reasonable.

When the time came for the maiden flight, everyone was expecting a spectacular failure. The chair defied logic and leaped into the air. It flew stable enough for [Josh] to take his fingers off the sticks. The pure excitement of seeing a crazy build that works is on full display as the entire Flite Test crew literally jumps for joy. [Alex] even throws in a cartwheel. This is the kind of story we love to cover here at Hackaday – watching a completely nutty build come together and perform better than anyone expected.

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