Should all Quadrotors Look like This?

In recent years, quadrotors have exploded in popularity. They’ve become cheap, durable, and can do some really impressive things, but are they the most efficient design? The University of Queensland doesn’t think so.

Helicopters are still much more efficient and powerful due to their one big rotor, and with the swashplate mechanism, perhaps even more maneuverable — after all did you see our recent post on collective pitch thrust vectoring? And that was a plane! A few quick searches of helicopter tricks and we think you’ll agree.

The new design, which is tentatively called the Y4, or maybe a “Triquad” is still a quadrotor, but it’s been jumbled up a bit, taking the best of both worlds. It has a main prop with a swashplate mechanism, and three smaller rotors fixed at 45 degree angles, that provide the counter torque — It’s kind of like a helicopter with three tails.

Regarding efficiency, the researchers expect this design could achieve an overall increase of about 25% in performance, compared to that of a standard quadrotor. So, they decided to test it and built a quad and a Y4 as similar as possible — the same size, mass, batteries, arms, and controller board. The results? The Y4 had an increased run time of 15%! They think the design could very well make the 25% mark, because in this test study, the Y4 was designed to meet the specifications of the quad, whereas a more refined Y4 without those limitations could perhaps perform even better.

Unfortunately there’s no video we can find, but if you stick around after the break we have a great diagram of how (and why) this design works!

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Hackers in Africa are building their own aircraft

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While you’re trying to come up with an idea for your next project this guy’s been building his own helicopter from whatever parts he can find. He’s just one of the aeronautical hackers featured in a story in the Daily Mail. The article’s narrative leaves us with many questions, but there’s enough info to make it worth a look.

In addition to the heli seen above there are also a couple of airplane builds to gawk at. Africa has already produced a couple of very ingenious hacks like [William Kamkwamba’s] projects which improved his village infrastructure. He gained enough notice from his work to land a scholarship to continue his education and that opportunity has also been afforded the creators of these aircraft.

At first we figured this helicopter project was possible because of lack of air traffic regulation in this part of the world. That’s not the case as [Onesmus Mwangi] — who makes his living as a farmhand — has been forbidden to fly the craft by local police. There may be another opportunity for him to fly later in life. He’s received funding to study aircraft maintenance abroad.+

Unfortunately we couldn’t find any video of this thing in action. If that’s unacceptable to you try getting your fix from this human-sized octocopter.

[Thanks Brandon]

Hackaday Links: February 28th, 2013

Xbox 360 control for a toy heli

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[Jason] leveraged the IR control libraries for Arduino to use an Xbox 360 controller to fly his Syma S107G helicopter.

Windows 7 running on Raspberry Pi

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Why, oh god why? Well, the guys at Shackspace got their hands on a laser cutter that can only be driven with a Windows program. Their solution was to run Win7 on RPi as a virtual machine.

Twin-servos for your third hand

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After growing tired of constantly flipping over the substrate being held with a third hand [Nidal] came up with a better way. He mounted his third hand on two servo motors so that it can be positioned with a joystick.

Depopulating SMD resistors

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If you’ve ever tried to remove small surface mount resistors or capacitors with an iron you know it can be tricky. Take a look at the technique that [Scott] uses to remove the components.

Photographing the die of MSP430, Z80, PIC, and several other chips

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Here’s the latest work from [Michail] on photographing the die of various chips. You may remember reading his previous post on decapping chips with boiling sulfuric acid.

Military steals idea of anyone who ever tied a cellphone camera to quadcopter

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Check out the toy this solder is using. It’s a tiny remote-controlled helicopter. The thing comes in a kit that includes a small tablet through which the nose-mounted camera image can be viewed. These are in use in Afghanistan by the UK Military. The purpose is to help protect foot soldiers by allowing them to perform discrete reconnaissance. What would you pay for this type of life saving technology? How does $31 million for 160 units sound? For that price we expect eight propellers and a cinema quality camera.

The drone is manufactured by Prox Dynamics. They’ve been in development since 2008 and you can bet that a lot of that time went into making it “inaudible” which is the main difference we see between this and hobby-built versions. For now you’ll have to deal with trying to make your own since they will only sell to the government.

The best we can do for you when it comes to video of the thing is prototyping footage from 2009 (after the break). If you have a link to a newer clip we’d love to see it in the comments.

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Communication protocol for an indoor helicopter

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There’s a special type of satisfaction that comes from really understanding how something works at the end of a reverse engineering project. This grid above is the culmination of [Spencer’s] effort to reverse engineer the IR protocol of a Propel ExecuHeli indoor helicopter toy.

The first thing he looked at was the three different controller channels which can be selected to allow multiple helicopters to be used in the same area. [Spencer] was surprised that they all used the same carrier frequency. The secret must be in the coded packets so his next challenge was to figure out how the data was being transmitted via the Infrared signal. It turns out the packets are using pulse-length coding (we were unfamiliar with this protocol but you can read a bit more about it here). The last piece of the puzzle was to capture packets produced by each unique change of the control module. With each bit (except for bit 11) accounted for he can now format his own codes for a controller replacement. Perhaps he’s looking to make the helicopter autonomous?

Autonomous helicopter works like a Wii remote

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[Jack Crossfire] took one of those inexpensive indoor helicopters and made it autonomous. He didn’t replace the hardware used for the helicopter, but augmented it and patched into the remote control to make a base station.

The position feedback is provided in much the same way that the Wii remote is used as a pointing device. On the gaming console there is a bar that goes under the TV with two IR LEDs in it. This is monitored by an IR camera in the Wii remote and used to calculate where you’re pointing the thing. [Jack’s] auto-pilot system uses two Logitech webcams with IR filters over the sensors. You can see them mounted on the horizontal bar in the cutout above. The helicopter itself has an IR LED added to it that is always on. The base station follows this beacon by moving the cameras with a pair of servo motors, calculating position and using it when sending commands to the remote control’s PCB.

Don’t miss the demo video of the rig after the break.

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Turning four smaller helicopters into one larger quadcopter

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There’s a reason we’ve seen a menagerie of quadcopters over the past few years – the key piece of any quadcopter build is an inertial measurement unit. Historically a very complicated and expensive piece of kit, these IMUs came down in price a few years back, allowing anyone with a few dollars in their pocket and a handful of brushless motors to build a four-bladed drone in their workshop.

[Starlino] built a few quadcopters, but he wanted to shy away from IMUs and get most of the mass of his new ‘copter over the center of the chassis. He came up with a design he calls the quadhybrid that can be built out of a quartet of those cheap 3-channel helicopter toys.

Most of the lift for [Starlino]’s quadhybrid comes from a pair of coaxial rotors from a Syma 001 3-channel helicopter toy. Anyone who has played with one of these toy helicopters knows how stable they are; if the tail rotor breaks, you’re left with a helicopter that can only go up and down.

To give his quadhybrid a few degrees of freedom, he attached four tail rotors from 3-channel helis to a few booms laid out in a cross pattern. By taking the receiver out of a 4-channel helicopter and adding his own controller board, [Starlino] made each of the tail rotors control the pitch and roll of the craft.

In the video after the break, you can see the quadhybrid is amazingly stable even without an IMU and surprisingly agile. As [Starlino]’s ‘copter can be made out of replacement parts for cheap 3-channel helis, we’ll expect a rush on these tail motors at your favorite online RC retailer very shortly.

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