Why No Plane Parachutes? And Other Questions.

This week I was approached with a question. Why don’t passenger aircraft have emergency parachutes? Whole plane emergency parachutes are available for light aircraft, and have been used to great effect in many light aircraft engine failures and accidents.

But the truth is that while parachutes may be effective for light aircraft, they don’t scale. There are a series of great answers on Quora which run the numbers of the size a parachute would need to be for a full size passenger jet. I recommend reading the full thread, but suffice it to say a ballpark estimate would require a million square feet (92903 square meters) of material. This clearly isn’t very feasible, and the added weight and complexity would no doubt bring its own risks.

Continue reading “Why No Plane Parachutes? And Other Questions.”

Truck-Sized Star Destroyer Takes Flight

While some of you may have been to see the new Star Wars movie, you might be sad that everything happened a long time ago in a galaxy far away. But there’s a group of RC enthusiasts called [Flite Test] who are trying to bring at least a little bit of that fantasy into real life. They’ve created a truck-sized Star Destroyer that actually flies. It looks kind of terrifying, too.

While it’s not as big as a “real” Star Destroyer, it’s certainly one of the biggest we’ve ever seen in real life. Built out of foam, this monstrosity is 15 feet long and powered by two huge electric motors and a large lithium polymer battery. Of course they didn’t start out by building this huge flying spaceship; they created a smaller model as proof-of-concept and flew that one around for a while to make sure everything was shipshape. While it’s exciting to see the small model in flight, it’s another thing to see the 15-foot version swooping around.

We’re sad to report that the Star Destroyer did meet a similar fate as the one that Rey was scavenging at the beginning of the movie (spoilers: it crashed), we hope that the RC team rebuilds it so it’s space worthy again. Maybe they can even add a real-life ion drive or a few lasers to make it even more real.

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Aircraft Hackchat This Thursday

This Thursday, December 10th at 5pm PST we will be hosting a live HackChat about aircraft. If it’s man-made and it files, it’s on topic! Full scale and model planes, helicopters, multicopters, gyros, blimps and gliders will be on the agenda. Our host this week will be Hackaday Community Editor [Adam Fabio] who is also the author of this well-written blog entry. In addition to being an electrical engineer, [Adam] brings 30 years of experience as a Radio Control model enthusiast. Over the years he’s worked as a professional R/C Blimp Pilot for the New York Islanders Hockey team and as an aerial photographer. On the full-scale aircraft side, he’s designed radar and air traffic control software used to keep the skies safe over land and sea.

Aircraft HackChat starts Thursday at 5pm PST (here’s a timezone cheat sheet if you need it). Participating in this live chat is very simple. Those who are already part of the Hacker Channel can simply click on theTeam Messaging button. If you’re not part of the channel, just go to the hacker Channel page, scroll to the bottom of the “TEAM” list in the left sidebar and click “Request to join this project”.

HackChat takes place in the Hacker Channel every few weeks and is a friendly place to talk about engineering and the projects you’re working on.

Hackaday Prize Entry: Tracking Rhinos With UAVs

For his Hackaday Prize project, [tlankford01] is using RC planes and UAVs as an anti-poaching system for rhinos and elephants. It’s a laudable goal for sure, but the conditions of this use case make for some very interesting engineering challenges.

The design goals [tlandford] has set are relatively simple for a bush plane, but building a plane that can fly 200km with a 6kg payload and return to base is a challenge that isn’t usually taken up by RC enthusiasts. For this project, [tlandford] is using an entirely 3D printed airframe, with living hinges printed right into the control surfaces. That in itself is pushing the limits of amateur airframes, but [tlandford] isn’t stopping there.

This UAV system will be completely automated, with a single ground control system taking care of controlling a swarm of planes, pointing a tracking antenna, and connecting to the Internet for observation or control from anywhere in the world.

The project that has seen a lot of improvement since it was entered in last year’s Hackaday Prize. The addition of a completely 3D printed airframe is a big one, and replacing the RVJet with something that looks a bit more like a glider should increase the loiter times over the target. There’s a video of the Icarus flying available below. If you also have a UAV project entered in The Hackaday Prize, there is now one obvious choice of what music you should use.

The 2015 Hackaday Prize is sponsored by:

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3D Printing RC Airplanes that Fly: An Engineer’s Chronicle

In the past, creating accurate replicas of models and fantasy objects was a task left to the most talented of cosplayers. These props need not be functional, though. [Steve Johnstone] takes replica model-building to the next step. He’s designing and building a model airplane that flies, and he’s documenting every step of the way.

Armed with a variety of 3D printing techniques and years of model-building experience, [Steve] is taking the lid off a number of previously undocumented techniques, many of which are especially relevant to the model-builder equipped with a 3D printer in the workshop.

As he continues his video log, [Steve] takes you through each detail, evaluating the quality of both his tools and techniques. How does a Makerbot, a Formlabs, and a Shapeways print stand up against being used in the target application? [Steve] evaluates a number of his turbine prints with a rigorous variable-controlled test setup.

How can we predict the plane’s center-of-gravity before committing to a physical design? [Steve] discusses related design decisions with an in-depth exploration of his CAD design, modeled down to the battery-pack wires. Though he’s not entirely finished, [Steve’s] work serves as a great chance to “dive into the mind of the engineer,” a rare opportunity when we usually discover a project after it’s been sealed from the outside.

3D printing functional parts with hobbyist-grade printers is still a rare sight, though we’ve seen a few pleasant and surprisingly practical components. With some tips from [Steve], we may complete this video journey with a few techniques that bump us out of the “novelty” realm and into a space where we too can start reliably printing functional parts. We’re looking forward to seeing the maiden voyage.

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Hackers in Africa are building their own aircraft

hacked-heli

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]

20 pounds and a gut feeling yields a configurable Rubidium atomic clock source

rubidium-source-for-twenty-pounds

So you see an image like this and the description “Aircraft stable oscillator” on an eBay listing for twenty pounds (about thirty bucks), what do you do? If you’re [Alecjw] you buy the thing and crack it open to find an atomic clock source inside. But he really went the distance with this one and figured out how to reconfigure the source from the way it was set up in the factory.

First off, the fact that it’s made for the aerospace industry means that the craftsmanship on it is simply fantastic. The enclosure is machined aluminum and all of the components are glued or otherwise attached to the boards to help them stand up to the high-vibrations often experienced on a plane. After quite a bit of disassembly [Alec] gets down to a black box which is labeled “Rubidium Frequency Standard”… jackpot! He had been hoping for a 10 MHz signal to use with his test equipment but when he hooked it up the source was putting out 800 kHz. With a bit more investigation he figured out how to reconfigure the support electronics to get that 10 Mhz source. We think you’re going to love reading about how he used a test crystal during the reconfiguration step.

Once he knew what he had he returned to the eBay seller and cleared out the rest of his stock.

[Thanks DIY DSP]