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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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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Aerodynamics? Super Honey Badger Don’t Give a @#*^@!


[Arron Bates] is a pro R/C Pilot from Australia. He’s spent the last few years chasing the dream of a fixed wing plane which could perform unlimited spins. After some promising starts with independently controlled wing spoilers, [Arron] went all in and created The Super Honey Badger. Super Honey Badger is a giant scale R/C plane with the tail of a helicopter and a soul of pure awesome.

Starting with a standard 87″ wingspan Extra 300 designed for 3D flight, [Arron] began hacking. The entire rear fuselage was removed and replaced with carbon fiber tubes. The standard Extra 300 tail assembly fit perfectly on the tubes. Between the abbreviated fuselage and the tail, [Arron] installed a tail rotor from an 800 size helicopter. A 1.25 kW brushless motor drives the tail rotor while a high-speed servo controls the pitch.

[Arron] debuted the plane at HuckFest 2013, and pulled off some amazing aerobatics. The tail rotor made 540 stall turn an easy trick to do – even with an airplane. Flat spins were a snap to enter, even from fast forward flight! Most of [Arron’s] maneuvers defy any attempt at naming them – just watch the videos after the break.

Sadly, Super Honey Badger was destroyed in May of 2014 due to a structural failure in the carbon tubes. [Arron] walked away without injury and isn’t giving up., He’s already dropping major hints about a new plane (facebook link).

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Droning On: PID Controllers and Bullet Connectors

droning-on-hill Not all drones are multirotors – Posing in our title photo are Maynard Hill and Cyrus Abdollahi. Maynard’s plane, TAM5 aka The Spirit of Butts Farm, is the smallest aircraft to make a transatlantic flight (YouTube link). Retracing the path of Alcock and Brown from Newfoundland to Ireland, the 6 pound (dry weight) model made the trip in just under 39 hours. All this happened in 2003, and was the cap on a lifetime of achievements for Hill. These are the types of pursuits that will be banned in the USA if the FAA restrictions go into effect.

Flight Controllers

Quite a few of you thought the Naze32 was left out of last column’s flight controller roundup. I hear you loud and clear! I’ll add the Naze to the controllers which will be tested on The Hackaday Testbed. The hard part is finding the darn things! I currently have an Acro Naze32 on its way to Droning On HQ.  If I can find a full version, I’ll add that.

PID Controllers Deep Dive

I’ve gotten a few questions on Proportional Integral Derivative (PID) controllers, so it is worth diving in a bit deeper to explain what a PID controller is. PID controllers are often found in process controls managing parameters like temperature, humidity, or product flow rate. The algorithm was initially designed in the late 1800’s as a method of controlling the helm of large naval ships. In fixed wing drones, PID keeps the plane’s wings level and on course. In multicopters, PID loops control heading, but they also provide the stable flight which allows the quadcopter to fly in the first place. A full explanation of PID loops would be beyond the scope of a single article, but let’s try a 10,000 foot explanation.

pidP: This is the “Present” parameter. P Has the most influence on the behavior of the aircraft.  If the wind blows your quadcopter from level flight into a 30 degree right bank, P is the term which will immediately take action to level the quad out. If the P value is too high, The quadcopter will overshoot level flight and start banking the other way. In fact, way too high a P value can cause a quadcopter to shake as it oscillates or “hunts” for level. Too Low a P value? the quadcopter will be very slow to react, and may never quite reach level flight again.

I: This the “Past” parameter. The I term dampens the overshoot and oscillations of the P term, and avoids the tendency of P to settle above or below the set point. Just like with P, too high an I term can lead to oscillation.

D: This is the “Future” parameter, and has the smallest impact on the behavior of the aircraft. In fact, some flight controllers leave it out entirely.  If P and I are approaching a set point too quickly, overshoot is likely to occur. D slows things down before the overshoot happens.

So why do multicopter pilots dread PID tuning?  Quite simply, it’s a tedious process. Couple a new pilot and an unproven aircraft with un-tuned PID values, and you have a recipe for frustration – and broken propellers. Things get even more complex when you consider the fact that there are at least 3 sets of PID variables to be tuned – Pitch, Roll, and Yaw. Some flight controllers now support multiple PID values depending on the style of flight. Want your plane or multicopter to fly around like a hotrod? You need a totally different set of PID values than a docile trainer craft. Rolf Bakke (KapteinKUK himself) made a video illustrating how multicopters behave when tuning PID values. You can easily see how a quad can go from “drunk” to “angry bee” with just a few value tweaks. All this is coming together with The Hackaday Testbed, which will help me in posting a few PID tuning videos of my own.

Hackaday Testbed Update

As for the testbed itself, it’s nearly complete! You can follow the progress on my Hackaday Projects Page. Most of the assembly has been relatively straightforward.   though of course there are always a few snags. It seems I always forget something when ordering up parts for coils-bada build. In this case it was 2.5mm banana plugs and motor mounting screws.

The Hobbyking motors attach to the frame with 3mm screws. The problem is that there really is no way to know how long the screws should be until you have the motors, mounting plates and drone frame on hand. I have a bunch of 3mm screws of various lengths, and thankfully there were enough screws of the correct length to mount the motors. Murphy is always at my side, as I accidentally grabbed a screw that was 1mm too long and, you guessed it, screwed right into the windings of the motor. Doh! Thankfully I had spares.

bullet-solderBullet connectors can be a real pain to solder. There are some jigs out there which help, but I’ve always found myself going back to the old “helping hands” alligator clips. Bullets tend to use lower gauge wire than we’re used to with regular electronics. 14, 12, even 8 gauge wires are used on R/C aircraft. A low power soldering iron with a surface mount tip just won’t cut it. Those irons just doesn’t have the thermal mass to get the connectors up to soldering temperature. This is one of those places where a decent 40 watt or better Weller iron (yes, the kind that plugs right in the wall) can be a godsend. I’m using an Metcal iron here, with a wide flat tip.

bullet-solder-2Bare bullet connectors and alligator clips can also create a problem – the metal clips create even more thermal mass. Years back an old-timer showed me a trick to handle this. Slip a piece of silicone R/C plane fuel tubing on the bullet, and then clip the helping hands onto the tube. The tube will act as insulation between the bullet and the clip. Silicone can easily withstand the temperatures of soldering. I’ve also used the silicone tube on the jaws themselves – though eventually the jaws will cut the soft tubing.

That’s about it for this edition Droning on! Until next time, keep ’em flying!

Title photo credit Cyrus Abdollahi.

Retrotechtacular: Build Yourself An Airplane


Planes these days are super complicated – think about the recent flaming-lithium battery issues in the B787 that may or may not have been solved – but it wasn’t always this way. Here’s a great example. The manufacture of a Piper J-3 Cub shows simple and efficient mechanical design brought to life in a multitude of steps all performed without automation.

The build starts with the frame. Pipes are nibbled into specialized fish mouths for a tight fit before being strapped to a jig and tack welded. With the fuselage in one piece the frame is removed for each joint to be fully welded and subsequently inspected. Cables are run through the frame to connect control surfaces to the cockpit. Continuing through to wing assembly we were especially surprised to see hand hammering of nails to secure the wood ribs to metal spars. How many nails do you think that worker pounded in a career? The entire aircraft is covered in fabric, an engine is added, and it’s into the wild blue yonder.

The look back at manufacturing techniques is interesting — do you think the large model shown in the video would be built these days, or would they just use a CAD rendering?

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Hackers in Africa are building their own aircraft


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]

Watermelon air boat


We think you’ll turn a few heads in Central Park if you’re driving a water melon around when everyone else is piloting sailboats. This watermelon is both sea worthy and radio controlled thanks to the work which [Starting Electronics] put into it.

We used this image because it shows you what’s inside of the hull, but you don’t want to miss the thing motoring around an above-ground swimming pool in the clip after the break. The hollowed out shell is quite buoyant and has no problem staying afloat and upright with the addition of a propeller. The parts from a remote control airplane kit have been mounted on a wooden scaffold. This provides plenty of thrust with a servo motor moving turning the prop for directional control. There is no dagger board so the craft is a bit slow to respond to turns. But how responsive do you expect a floating melon to be?

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