Flight Of The Pterothopter: A Jurassic-Inspired Ornithopter

Ornithopters look silly. They look like something that shouldn’t work. An airplane with no propeller and wings that go flappy-flappy? No way that thing is going to fly. There are, however, a multitude of hobbyists, researchers, and birds who would heartily disagree with that sentiment, because ornithopters do fly. And they are almost mesmerizing to watch when they do it, which is just one reason we love [Hobi Cerdas]’s build of the Pterothopter, a rubber band-powered ornithopter modeled after a pterodactyl.

All joking aside, the science and research behind ornithopters and, relatedly, how living organisms fly is fascinating in itself — which is why [Lewin Day] wrote that article about how bees manage to become airborne. We can lose hours reading about this stuff and watching videos of prototypes. While most models we can currently build are not as efficient as their propeller-powered counterparts, the potential of evolutionarily-perfected flying mechanisms is endlessly intriguing. That alone is enough to fuel builds like this for years to come.

As you can see in the video below, [Hobi Cerdas] went through his own research and development process as he got his Pterothopter to soar. The model proved too nose-heavy in its maiden flight, but that’s nothing a little raising of the tail section and a quick field decapitation couldn’t resolve. After a more successful second flight, he swapped in a thinner rubber band and modified the wing’s leading edge for more thrust. This allowed the tiny balsa dinosaur to really take off, flying long enough to have some very close encounters with buildings and trees.

For those of you already itching to build your own Pterothopter, the plans come from the Summer 2017 issue of Flapping Wings, the official newsletter of the Ornithopter Society (an organization we’re so happy to learn about today). You can also find more in-depth ornithopter build logs to help you get started. And, honestly, there’s no reason to limit yourself to uncontrolled flight; we’ve come across some very impressive RC ornithopters in the past.

Continue reading “Flight Of The Pterothopter: A Jurassic-Inspired Ornithopter”

Diaphragm Air Engine

One of the tricky parts of engineering in the physical world is making machines work with the available resources and manufacturing technologies. [Tom Stanton] has designed and made a couple of air-powered 3D printed engines but always struggled with the problem of air leaking past the 3D-printed pistons. Instead of trying to make an air-tight piston, he added a rubber membrane and a clever valve system to create a diaphragm air engine.

This GIF is worth 115 words

A round rubber diaphragm with a hole in the center creates a seal with the piston at the top of its stroke. A brass sleeve and pin protrude through the diaphragm, and the sleeve seals create a plug with an o-ring, while the pin pushes open a ball which acts as the inlet valve to pressurize an intermediate chamber. As the piston retracts, the ball closes the inlet valve, the outlet valve of the intermediate chamber is opened, forcing the diaphragm to push against the piston. The seal between the piston and diaphragm holds until the piston reaches its bottom position, where the pressurized air is vented past the piston and out through the gearbox. For full details see the video after the break.

It took a few iterations to get the engine to run. The volume of the intermediate chamber had to increase and [Tom] had to try a few different combinations of the sleeve and pin lengths to get the inlet timing right. Since he wanted to use the motor on a plane, he compared the thrust of the latest design with that of the previous version. The latest design improved efficiency by 366%. We look forward to seeing it fly! Continue reading “Diaphragm Air Engine”

This Hurricane Uses A Novel Technique

You’ve probably heard of the brave pilots, the so-called ‘few’, that took to the air in their Supermarine Spitfires and saved the day during the Battle of Britain. It’s a story that contains a lot of truth, but as is so often the case, it masks a story with a bit more complexity. Those pilots did scramble across the airfields of Southern England back in the summer of 1940, but more of them went into battle behind the controls of a Hawker Hurricane than its more glamorous stablemate.

The Hurricane might have been eclipsed by the Spitfire in the public’s eye, but not for [Marius Taciuc], who’s made a fully-functional RC model of one. Normally that wouldn’t be worthy of our attention, but in this case he’s employed a rather fascinating construction technique. He’s recreated the doped-fabric skin of the original by 3D-printing the frame of the aircraft and covering it in heat-shrink film, making this a very rare bird indeed.

The video below takes us through the steps including the development of the frame in a CAD package based on a tracing of a 2D aircraft picture, fitting the film, and finally attempts at flight that are unfortunately foiled by inappropriate wheel choice. But the short flight and crash does demonstrate that this construction method is durable, which leads on to our interest in it. While it evidently makes a functional aircraft, there are other applications that could benefit from such a lightweight and strong combination of materials.

[Marius] actually created a model of the somewhat more photogenic Spitfire using a similar technique, though as far as we can tell, that one has remained grounded. Incidentally, these pages have been previously graced by Hurricanes of the non-PLA variety. Continue reading “This Hurricane Uses A Novel Technique”

Your Drone Is Cool, But It’s No Jet Fighter

There are some communities with whom our happy band of hardware hackers share a lot in common, but with whom we don’t often associate. The more workshop-orientated end of the car modification or railway modeler scenes, for instance, or the model aircraft fraternity. Many of these communities exist more for the activity than for the making, some of them dabble with building kits, but among them are a hard core of people who create amazing projects from scratch.

Take [Igor Negoda], for example. Not content with building just any model aircraft, he’s built his own from scratch, to his own design. And if designing for yourself what amounts to a scaled-down jet fighter wasn’t enough, he’s also built his own jet engine to power it. His videos are all in Russian so use YouTube’s subtitle feature if you’re not a Russian speaker, but they’re so good that if you couldn’t access the English translation you’d want to learn the language just to hear his commentary.

The video below the break shows us first a fast-taxi test using a ducted fan, then a full test flight with the jet engine. There is an explanation of the fuel system and the flight control systems, before an impressive flight from what appears to be a former Cold War-era runway. There are a few funny moments such as transporting a large model jet aircraft in a small hatchback car, but the quality of the work in a garage workshop shines through. Suddenly a multirotor doesn’t cut it any more, we want a jet aircraft like [Igor]’s!

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Here’s The Reason The FAA’s Drone Registration System Doesn’t Make Sense

Last week, the US Department of Transportation and FAA released their rules governing drones, model aircraft, unmanned aerial systems, and quadcopters – a rose by any other name will be regulated as such. Now that the online registration system is up and running.

The requirements for registering yourself under the FAA’s UAS registration system are simple: if you fly a model aircraft, drone, control line model, or unmanned aerial system weighing more than 250g (0.55 lb), you are compelled under threat of civil and criminal penalties to register.

This is, by far, one of the simplest rules ever promulgated by the FAA, and looking at the full text shows how complicated this rule could have been. Representatives from the Academy of Model Aircraft, the Air Line Pilots Association, the Consumer Electronics Association weighed in on what types of aircraft should be registered, how they should be registered, and even how registration should be displayed.

Considerable attention was given to the weight limit; bird strikes are an issue in aviation, and unlike drones, bird strikes have actually brought down airliners. The FAA’s own wildlife strike report says, “species with body masses < 1 kilogram (2.2 lbs) are excluded from database,”. The Academy of Model Aircraft pushed to have the minimum weight requiring registration at two pounds, citing their Park Flyer program to define what a ‘toy’ is.

Rules considering the payload carrying ability of an unmanned aerial system were considered, the inherent difference between fixed wing and rotors or quadcopters was considered, and even the ability to drop toy bombs was used in the decision-making process that would eventually put all remotely piloted craft weighing over 250g under the FAA’s jurisdiction. We must at least give the FAA credit for doing what they said they would do: regulate drones in a way that anyone standing in line at a toy store could understand. While the FAA may have crafted one of the simplest rules in the history of the administration, this rule might not actually be legal.

Continue reading “Here’s The Reason The FAA’s Drone Registration System Doesn’t Make Sense”

FAA Releases Rules Governing Unmanned Aerial Systems

The US Department of Transportation and the FAA have just released their guidelines that require registration of Unmanned Aerial Systems. This is the regulation that covers model aircraft, drones, quadcopters, and flying toys of all kinds. These rules have been anticipated since last month to be in place for the holiday season.

As expected, the FAA is requiring registration for all aircraft, regardless of being ‘model’ aircraft or not, weighing more than 250 grams (0.55 pounds) and less than 55 pounds. The maximum weight is a holdover from previous regulations; model aircraft weighing more than 55 pounds were never really legal without a permit. It should be noted that anyone can build a quadcopter with cameras and video transmitters weighing less than 250 grams. These quadcopters are not ‘toys’ by any means, but are not required to be marked with a registration number and the pilot is not required to actually register. As expected, most rules governing the actual flight of these aircraft remain in place – don’t fly above 400 feet, don’t fly within five miles of an airport.

Registration is by pilot, not aircraft, and costs $5. A registration number must be put on every aircraft the pilot owns, and penalties for not registering can include up to $27,500 in civil penalties and up to $250,000/3 years imprisonment in criminal penalties. The full rules are available in this 200-page PDF. As with most government regulations, there will be a 30-day RFQ period beginning December 21st on regulations.gov. The docket number is FAA-2015-7396.

Congress Destroys A Hobby, FAA Gets The Blame

As ordered by the US Congress, the FAA is gearing up to set forth a standard for commercial UAVs, Unmanned Aerial Systems, and commercial drones operating in America’s airspace. While they’ve been dragging their feet, and the laws and rules for these commercial drones probably won’t be ready by 2015, that doesn’t mean the FAA can’t figure out what the rules are for model aircraft in the meantime.

This week, the FAA released its interpretation (PDF) of what model aircraft operators can and can’t do, and the news isn’t good: FPV flights with quadcopters and model airplanes are now effectively banned, an entire industry centered around manufacturing and selling FPV equipment and autopilots will be highly regulated, and a great YouTube channel could soon be breaking the law.

The FAA’s interpretation of what model aircraft can and cannot do, and to a larger extent, what model aircraft are comes from the FAA Modernization And Reform Act Of 2012 (PDF). While this law states the, “…Federal Aviation Administration may
not promulgate any rule or regulation regarding a model aircraft…” it defines model aircraft as, “an unmanned aircraft that is capable of sustained flight in the atmosphere; flown within visual line of sight of the person operating the aircraft; and flown for hobby or recreational purposes.” The FAA has concluded that anything not meeting this definition, for example, a remote controlled airplane with an FPV setup, or a camera, video Tx and Rx, and video goggles, is therefore not a model aircraft, and falls under the regulatory authority of the FAA.

In addition, the FAA spent a great deal of verbiage defining what, “hobby or recreational purposes” in regards to model aircraft are. A cited example of a realtor using a model aircraft to take videos of a property they are selling is listed as not a hobby or recreation, as is a farmer using a model aircraft to see if crops need water. Interestingly, receiving money for demonstrating aerobatics with a model aircraft is also not allowed under the proposed FAA guidelines, a rule that when broadly interpreted could mean uploading a video of yourself flying a model plane, uploading that to YouTube, and clicking the ‘monetize’ button could soon be against the law. This means the awesome folks at Flite Test could soon be out of a job.

The AMA, the Academy Of Model Aeronautics, and traditionally the organization that sets the ‘community-based set of safety guidelines’ referred to in every law dealing with model aircraft, are not happy with the FAA’s proposed rules (PDF). However, their objection is a breathless emotional appeal calls the proposed rules a, “a strict regulatory approach to the operation of model aircraft in the hands of our youth and elderly members.” Other than offering comments per the FAA rulemaking process there are, unfortunately, no possible legal objections to the proposed FAA rules, simply because the FAA is doing exactly what congress told them to do.

The FAA is simply interpreting the Modernization And Reform Act Of 2012 as any person would: FPV goggles interfere with the line of sight of an aircraft, thus anyone flying something via FPV goggles falls under the regulatory authority of the FAA. Flying over the horizon is obviously not line of sight, and therefore not a model aircraft. Flying a model aircraft for money is not a hobby or recreation, and if you’re surprised about this, you simply aren’t familiar with FAA rules about money, work, and person-sized aircraft.

While the proposed FAA rules are not yet in effect, and the FAA is seeking public comment on these rules, if passed there will, unfortunately, exactly two ways to fix this. The first is with a change in federal law to redefine what a model aircraft is. Here’s how to find your congresscritter, with the usual rules applying: campaign donations are better than in-person visits which are better than letters which are better than phone calls which are better than emails. They’ll also look up if you have voted in the last few elections.

If passed, the only other way these rules will align with the privileges model aircraft enthusiasts have enjoyed for decades is through a court ruling. The lawsuit objecting to these rules will most likely be filed by the AMA, and if these rules pass, a donation or membership wouldn’t be a bad idea.