Propeller Backpack For Lazy Skiers

April 7, 2017 by Anool Mahidharia 21 Comments

At first glance, it looks eerily similar to Inspector Gadget’s Propeller Cap, except it’s a backpack. [Samm Sheperd] built a Propeller Backpack (video, embedded after the break) which started off as a fun project but almost ended up setting him on fire.

Finding himself snowed in during a spell of cold weather, he found enough spare RC and ‘copter parts to put his crazy idea in action. He built a wooden frame, fixed the big Rimfire 50CC outrunner motor and prop to it, slapped on a battery pack and ESC, and zip-tied it all on to the carcass of an old backpack.

Remote control in hand, and donning a pair of Ski’s, he did a few successful trial runs. It looks pretty exciting watching him zip by in the snowy wilderness. Well, winter passed by, and he soon found himself in sunny California. The Ski’s gave way to a bike, and a local airfield served as a test track. He even manages to put in some exciting runs on the beach. But the 10S 4000 mAH batteries seem to be a tad underpowered to his liking, and the motor could do with a larger propeller. He managed to source a 12S 10,000 mAH battery pack, but that promptly blew out his Aerostar ESC during the very first static trial.

He then decided to rebuild it from ground up. A ten week welding course that he took to gain some college credits proved quite handy. He built a new TiG welded Aluminium frame which was stronger and more lightweight than the earlier wooden one. He even thoughtfully added a propeller safety guard after some of his followers got worried, although it doesn’t look very effective to us. A bigger propeller was added and the old burnt out ESC was replaced with a new one. It was time for another static trial before heading out in to the wide open snow again. And that’s when things immediately went south. [Samm] was completely unaware as the new ESC gloriously burst in to flames (8:00 into the third video), and it took a while for him to realize why his video recording friend was screaming at him. Check out the three part video series after the break to follow the story of this hack. For a bonus, check out the 90 year old gent who stops by for a chat on planes and flying (8:25 in the third video).

But [Samm] isn’t letting this setback pin him down. He’s promised to take this to a logical finish and build a reliable, functional Propeller Backpack some time soon. This isn’t his first rodeo building oddball hacks. Check out his experiment on Flying Planes With Squirrel Cages.

We seem to be catching a wave of wind-powered transportation hacks these days. Hackaday’s own [James Hobson] spent time in December on a similar, arguably safer, concept. He attached ducted fans to the back of a snowboard. We like this choice since flailing limbs won’t get caught in these types of fans.

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Hackaday Prize Entry: Electric Variable Pitch Props

April 3, 2017 by Brian Benchoff 39 Comments

Barring the smallest manned airplanes, most aircraft that are pulled around by a prop have variable pitch propellers. The reason for this is simple efficiency. Internal combustion engines are most efficient at a specific RPM, and instead of giving the engine more gas to speed up, pilots can simply change the pitch of a propeller. With a gas powered engine, the mechanics and design of variable pitch propellers are well understood and haven’t really changed much in decades. Adding variable pitch props to something pulled around by an electric motor is another matter entirely. That’s what [Peter McCloud] is building for his entry to the Hackaday Prize, and it’s going into the coolest project imaginable.

This project is designed for a previous Hackaday Prize entry, and the only 2014 Hackaday Prize entry that hasn’t killed anyone yet. Goliath is a quadcopter powered by a lawnmower engine, and while it will hover in [Peter]’s test rig, he’s not getting the lift he expected and the control system needs work. There are two possible solutions to the problem of controlling the decapatron: an ingenious application of gimballed grid fins, or variable pitch rotors. [Peter] doesn’t know if either solution will work, so he’s working on both solutions in parallel.

[Peter]’s variable pitch rotor system is basically an electronic prop mount that connects directly to the driven shafts on his gas-powered quadcopter. To get power to the electronics, [Peter] is mounting permanent magnets to the quad’s frame, pulling power from coils in the rotor hub, and rectifying it to DC to drive the servos and electronics. Control of the props will be done wirelessly through an ESP32 microcontroller.

Variable pitch props are the standard for everything from puddle jumpers to acrobatic RC helis. In the quadcopter world, variable pitch props are at best a footnote. The MIT ACL lab has done something like this, but perhaps the best comparison to what [Peter] is doing is the incredible Stingray 500 quad. Flite Test did a great overview of this quad (YouTube), and it’s extremely similar to a future version of the Goliath. A big motor (in the Stingray’s case, a brushless motor) powers all the props via a belt, and the pitch of the props is controlled by four servos. The maneuverability of these variable pitch quads is unbelievable, but since the Goliath is so big and has so much mass, it’s doubtful [Peter] will be doing flips and rolls with his quads.

You can check out a video of [Peter]’s build below.

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Flexible Quadcopter Is Nearly Indestructible

March 18, 2017 by Will Sweatman 20 Comments

We’ve all crashed quadcopters. It’s almost inevitable. Everything is going along fine and dandy ’till mother nature opens her big mouth a blows a nasty gust of wind right at you, pushing your quad into the side of a wall. A wall that happens to be composed of a material that is quite a bit harder than your quadcopter. “What if…” you ask yourself while picking up the pieces of you shiny new quad off the ground… “they made these things out of flexible material?”

Well, it would appear someone has done just that. The crash resistant quadcopter is composed of a flexible frame (obviously) which is held rigid with magnets. So the frame works just like the frame of your average quad. Until you crash it, of course. Then it becomes flexible.

The idea came from the wing of a wasp, which you can apparently crumple without damaging it. Be sure to check out the video below of the drone showing off its flexible frame, and let us know if you’ve seen any other types of flexible frame drones in the wild.

Thanks to [JDHE] for the tip!

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Welcome To The Drone Wars

March 18, 2017 by Elliot Williams 18 Comments

“DroneClash” is a competition to be held on December 4th (save the date!) in a hangar at Valkenburg airfield in the Netherlands. The game? Teams try to destroy each others’ quadcopters, navigate through a “Hallway of Doom, Death, and Destruction”, and finally enter a final phase of the game where they try to defend their “queen” drone while taking out those of their opponents.

This sounds like crazy and reckless fun. Surprisingly, it’s being sponsored by the Technical University of Delft’s Micro Air Vehicle (MAV) lab. The goal is to enable a future of responsible drone use by having the ability “to take them out if necessary”.

Drone development has grown hugely in recent years, and you can see the anti-drone industry growing too. Ideally, these developments keep each other in check and result in a safe and responsible incorporation of drones in our daily lives. We are organising DroneClash to generate new ideas in order to encourage this process.

We do have to ask ourselves why anyone would want to use another quadcopter to take out illegally operated quadcopters — there must be a million more effective means from a policing standpoint. On the other hand, if we were re-shooting “Hackers” right now, and looking for a futuristic sport, we would swap out rollerblading for drone combat. Registration opens this week. Gentlebots, start your engines.

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Building Homebrew VTOL Rockets

February 16, 2017 by Brian Benchoff 35 Comments

No one can deny what SpaceX and Blue Origin are doing is a feat of technological wizardry. Building a rocket that takes off vertically, goes into space, and lands back on the pad is an astonishing technical achievement that is literally rocket science. However, both SpaceX and Blue Origin have a few things going for them. They have money, first of all. They’re building big rockets, so there’s a nice mass to thrust cube law efficiency bump. They’re using liquid fueled engines that can be throttled.

[Joe Barnard] isn’t working with the same constraints SpaceX and Blue Origin have. He’s still building a rocket that can take off and land vertically, but he’s doing it the hard way. He’s building VTOL model rockets. Most of the parts are 3D printed. And he’s using solid motors you can buy at a hobby shop. This is the hard way of doing things, and [Joe] is seeing some limited success with his designs.

While the rockets coming out of Barnard Propulsion Systems look like models of SpaceX’s test vehicles, there’s a lot more here than looks. [Joe] is using a thrust vectoring system — basically mounting the Estes motor in a gimbal attached to a pair of servos. This allows the rockets to fly straight up without fins or even the launch rod used to get the rocket up to speed in the first few millseconds of flight. This is active stabilization of a model rocket, with the inevitable comments of ITAR violations following soon afterward.

Taking off vertically is one thing, but [Joe] is also trying to land his rockets vertically. Each rocket he’s built has a second Estes motor used only for landing. During descent, the onboard microcontroller calculates the speed, altitude, and determines if it’s safe to attempt a vertical landing. If the second motor has sufficient impulse to make velocity and altitude equal zero at the same time, the landing legs deploy and the rocket hopefully makes a soft touchdown in the grass.

While [Joe] hasn’t quite managed to pull off a vertical takeoff and landing with black powder motors quite yet, he’s documenting and livestreaming all of his attempts. You can check out the latest one from a week ago below.

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Drone-Drone

February 15, 2017 by Pedro Umbelino 24 Comments

Yes, the pun was ripped off the article that got our attention . It was just too good not to share. A team of researchers in Japan created an artificial honeybee, a small drone that is meant to cross-pollinate flowers. The (still) manually controlled drone is 4 centimetres wide and weighs only 15 grams. At the bottom side of the drone, a mix of a special sticky gel and horse hair resides. The purpose of this gel is to collect the pollen particles as it bumps into the flowers and exchange it as it goes hopping around from plant to plant. In experiments, the drone was able to cross-pollinate Japanese lilies (Lilium japonicum) without damaging the plant, stamens or pistils when the drone flew into the flowers.

The gel used for the artificial pollinators was the result of a failed experiment back in 2007. While researching electrical conduction liquids, Eijiro Miyako, a chemist at the National Institute of Advanced Industrial Science and Technology (AIST) Nanomaterial Research Institute, produced a sticky gel with no useful electrical characteristics and stored it away in a cabinet. After 8 years, when cleaning the cabinet, he found the gel still sitting there, unspoiled.

“This project is the result of serendipity. We were surprised that after 8 years, the ionic gel didn’t degrade and was still so viscous. Conventional gels are mainly made of water and can’t be used for a long time, so we decided to use this material for research.”

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PVC Submersible ROV

February 10, 2017 by Pedro Umbelino 18 Comments

[mark.brubaker.1] and his crew decided to make a submersible for a school project using PVC pipes as a frame. It has two motors on the back to provide forward thrust and steering as well as a horizontal mounted motor in the middle of the PVC chassis to provide up and down thrust. They used regular motors which they waterproofed by inserting them inside a case full of plumbers wax. We’re not sure how long this will hold at the bottom of the ocean, but it works fine for a school project in the pool. Here’s the instructions on how to make one.

The build is completely analog, the controller is a board with three switches which individually control the different motors. So if you want to turn left, you fired up the right motor. For right you do the opposite and fire up the left motor. Up and down, well, you get the picture. If you have a swimming pool, lake or some water body nearby and you’re looking for a weekend project with your kids, this is a great tip. It’s not an Arduino controlled robot fish, but it’s a first step in that direction; you can later on use the frame to improve on the design and add some electronics.

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