Turn Drone Into A Large Propeller To Increase Hover Efficiency

Multirotor drones are significantly more popular than conventional helicopter designs for many reasons, which do not include efficiency. Making use of the aerodynamic effects behind this, [Nicholas Rehm] was able to significantly increase the efficiency of his experimental tricopter by turning it into one large spinning propeller.

Since aerodynamic drag is proportional to velocity, a small, high-RPM propeller will require more power to produce the same thrust as a large, low-RPM propeller. With this in mind, [Nicholas] built a tricopter that can rotate all three long arms together using a single servo, giving it very aggressive yaw control. By attaching a wing to each of the arms, it becomes a large variable pitch propeller powered by tip thrusters.Power draw graph

To measure the efficiency of the craft, a small lidar sensor was added to allow accurate PID altitude control. While keeping the drone at a constant altitude a few feet off the ground, [Nicholas] measured the power draw of the motors in a hover, and then let the drone spin around its yaw axis up to almost 5 rev/s.

At a spin rate of 4 rev/s, the power draw of the motors was reduced by more than 60%. Even compared to the drone without the added weight of the wings, it still used 50% less power to maintain altitude.

Since [Nicholas] hadn’t yet implemented horizontal position control while spinning, the length of each test run was limited by the wind drift. He plans to solve this, and also do some testing of the drone in horizontal flight, where the added airfoils will also increase efficiency.

We’ve featured a few of [Nicholas]’ flying machines here on Hackaday, including a foam F-35 VTOL and a cyclocopter. Most of his aircraft run his open source dRehmFlight flight stabilization, created specifically for hacking.

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Hackaday Prize Entry: Bloodhound Autonomous Radiolocation Drone

If you’re a first responder — say, searching for someone lost in the outback, or underneath an avalanche — and you’re looking for someone with a radio beacon, what’s the fastest way to find that beacon? Getting up high would be a good idea, and if you’re using radio direction finding, you’ll want to be able to cover a lot of ground quickly if only to make the triangulation a bit easier. High and fast — sounds like the perfect opportunity for a drone, right?

[Phil Handley]’s Bloodhound project is an autonomous drone that can scan a wide area, listening for emergency beacons while alerting the search and rescue personnel. His test bed tricopter uses DT750 brushless outrunners controlled by 18A Turnigy Plush ESCs and powered by a 2200mAh LiPo. A metal-gear servo works the yaw mechanism. He’s also got a Pixhawk Autopilot, a ArduPilot flight controller, a NavSpark GPS, a software defined radio dongle, and a Raspberry Pi. He made the air frame out of wooden dowels, following RCExplorer’s tricopter design.

The next challenge involves radio direction finding, essentially creating Bloodhound’s foxhunting skills. It needs to be able to autonomously track down a signal by taking readings from multiple angles. In addition to finding lost skiers, [Phil] also envisioned Bloodhound being used to track other beacons, of course—such as wildlife transponders or errant amateur rockets.

Multicopters And Their MultiWii Beginnings

With more than five years down the road in this successful hack, [Alexinparis] and his pioneering Nintendo controller hack have been taking eager enthusiasts to the skies with homebrew multicopters armed with MultiWii firmware.

The MultiWii firmware, like most other glorious moments that gloss these pages, was as a hack, and a darn good one. By harvesting the (I²C-based) accel-gyro sensor package in a Nintendo Wii MotionPlus, [Alexinparis] developed control firmware for an Arduino Pro Mini, and, thus: the MultiWii Controller Board was born. With a successful WiiMotion Plus pcb extraction, an Arduino Pro Mini, and some help from the forums, the dedicated hobbyist could build their own flying platform with customizable firmware enabling bi, tri, quad, hex, octo, Y6, and Y4 propeller configurations.

With a working flight controller, [Alexinparis] sent his firmware skyward in a tricopter built from scratch. For a light-but-sturdy shell, he opted for a lost-foam cast hull made from fiberglass and carbon fiber tow. This hull houses most of the electronics safely inside the hollow shell while maintaining the strength to sustain heavy blows from crashes. (The version shown above features additional carbon fiber reinforcement in the center.)

multiwiiLostFoammultiwiiLostFoamHousingmultiwiiDone

More than five years later, MultiWii is a mature open-source project with firmware and wiki under constant update. If you’ve ever considered getting started with multicopters, this project stands as a tested-and-tried road to success. In fact, even RC vendor HobbyKing offers low-cost Multiwii PCBs compatible with the firmware. For more details on the project’s humble beginnings, head on over to the RC Groups thread and followup documentation thread.

We’ve seen MultiWii countless times in the past as the firmware in numerous multicopter builds. It’s about time we give [Alexinparis] some well-deserved credit for paving the way.

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Hackaday Links: March 1, 2015

The somewhat regular Hardware Developers Didactic Galactic was a few days ago in San Francisco. Here’s the video to prove it. Highlights include [James Whong] from Moooshimeter, the two-input multimeter, [Mark Garrison] from Saleae, and a half-dozen other people giving talks on how to develop hardware.

[Taylor] made a portable NES with a retron, a new-ish NES clone that somehow fits entirely in a glop top IC. The controllers sucked, but [Taylor] made a new one with touch sensors. All that was required was eight transistors. The enclosure is an Altoid tin, and everything works great.

Here’s a YouTube channel you should subscribe to: Ham College. The latest episode covers the history of radio receivers and a crystal radio demonstration. They’re also going through some of the Technical class question pool, providing the answers and justification for those answers.

[Prusa] just relaunched prusaprinters and he’s churning out new content for it. Up now is an interview with [Rick Nidata] and his awesome printed container ship.

The tip line is overflowing with ESP8266 breakout boards. Here’s the simplest one of them all. It’s a breadboard adapter with stickers on the pin headers. Turn that into a right-angle breadboard adapter, and you’ll really have something.

Here’s something that’s a bit old, but still great. [Dillon Markey], one of the stop-motion animators for Robot Chicken modified a Nintendo Power Glove for animation duties. It seems to work great, despite being so bad. Thanks [Nicholas] for the link.

[David] the Swede – a consummate remote control professional we’ve seen a few times before – just flew his tricopter in a mall so dead it has its own Wikipedia page. Awesome tricopter, awesome location, awesome video, although we have to wonder how a few really, really bright LEDs would make this video look.

Here’s an item from the tip line. [Mark] wrote in with an email, “Why do you put names in [square brackets] in the blog entries? Just curious.” The official, [Caleb]-era answer to that question is that sometimes people have bizarre names that just don’t work in text. Imagine the sentence, “[12VDC] connected the wires to the terminal” without brackets. The semi-official answer I give is, “because.”

Modular Multicopter Core Flies In Multiple Orientations

[Ioannis Kedros] claims to be rather new to the game of building multi-rotor drones. You’d never know it looking at his latest creation. Yes, we’re talking about the quadcopter seen here, but it’s the core of the machine that’s so interesting. He came up with a PCB hub that allows multiple orientations to be used with the same board. These include tri-copter, and quadcopter with different strut angles for different applications.

multicopter-hub-pcbThe silk screen of the PCB has dotted lines showing the different angles possible for one pair of motor supports. One set makes a perfect “X” for traditional quadcopter flight. Another reduces the angle between front and back struts for higher-performance quad flight, while the last set is intended for a tricopter setup.

We’d recommend taking a look at [Ioannis’] project writeup whether this particular application interests you or not. His design techniques go through all possible manner of checks before placing the PCB order. There is no substitute for this process if you want to avoid getting burnt by silly mistakes.

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Rotor DR1 And Collaborative Development

In a post apocalyptic world ravaged by the effects of a virus, a young man searches for his father. He forms a friendship with a young woman and a delivery drone that seems oddly sentient. Together they have to fight through abandoned buildings, and past gangs of thugs, to find…

That’s the hook for Rotor DR1, a web series currently in production. Rotor DR1 isn’t a big budget movie, but an independent series created by [Chad Kapper]. [Chad] isn’t new to film or drones, his previous project was Flite Test, which has become one of the top YouTube channels for drones and radio controlled aircraft in general. With the recent sale of Flite Test to Lauren International, [Chad] has found himself with the time to move forward on a project he’s been talking about for years.

Click past the break for more information, and to check out the Rotor DR1 trailer.

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X-Wing Tri-Rotor Brings Star Wars To Life

xwing

Once you realize you can make almost anything fly if you strap a big enough prop and motor to it, you really start thinking outside of the box. That’s what [Rodger] did and he’s come up with this very impressive 19lb, 5′ long X-Wing Fighter from Star Wars.

Recently [Rodger] has found new joy in making movie props come to life with the help of today’s technology. He started with Project Thunderball — a flying James Bond mannequin with a jet pack. From there he brought us the Marty McFly working hover-board, and now an X-Wing Fighter, his biggest flying machine yet.

It measures about 5 feet long, and is a tri-rotor design with three 100A ESCs, 1200W 1050KV motors, and 12″ rotors. The frame is made of PVC to conserve weight. Since it’s a tri-rotor with true vectored thrust, the X-Wing features much better yaw than quadrotors. Then only problem is it pivots around the odd prop out, meaning in this case, the X-Wing turns on its nose — instead of its tail.

Regardless, we can’t wait to see what [Rodger] tries flying next! Stick around to see the X-Wing in action.

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