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.
Bees. The punchline to the title is bees carrying sensors like little baby bee backpacks. We would run out of fingers counting the robots which emulate naturally evolved creatures, but we believe there is a lot of merit to pirating natural designs, but researchers at the University of Washington cut out the middle-man and put their sensors right on living creatures. They measured how much a bee could lift, approximately 105 milligrams, then built a sensor array lighter than that. Naturally, batteries are holding back the design, and the rechargeable lithium-ion is more than half of the weight.
When you swap out brushless motors for organics, you gain and lose some things. You lose the real-time control, but you increase the runtime. You lose the noise, but you also lose the speed. You increase the range, but you probably wind up visiting the same field over and over. If your goal is to monitor the conditions of flowering crops, you may be ready to buy and install, but for the rest of us, dogs are great for carrying electronics. Oh yes. Cats are not so keen. Oh no.
One of humankind’s dreams has always been to fly like a bird. For a hacker, an achievable step along the path to that dream is to make an ornithopter — a machine which flies by flapping its wings. An RC controlled one would be wonderful, controlled flight is what everyone wants. Building a flying machine from scratch is a big enough challenge, and a better jumping-off point is to make a rubber band driven one first.
I experimented with designs which are available on the internet, to learn as much as possible, but I started from scratch in terms of material selection and dimensions. You learn a lot about flight through trial and error, and I’m happy to report that in the end I achieved a great little flyer built with a hobby knife and my own two hands. Since then I’ve been looking back on what made that project work, and it’s turned into a great article for Hackaday. Let’s dig in!
We’re actually going to link to an old post from back in February because we think it’s equally as impressive as the most recent work. This is a 3D printed ornithopter powered by a rubber band (translated). The frame is much like a traditional rubber band plane. The difference is that after winding it up it doesn’t spin a propeller. The flapping of the four plastic membrane wings makes it fly like magic. Seriously, check out the demo below… we almost posted this as “Real or Fake?” feature if we hadn’t seen similar offerings a couple of years back.
The flight lasts a relatively long time when considering the quick winding before launch is all that powered it. But the most recent offerings (translated) from the site include the motorized ornithopter design seen above. It carries a small Lithium cell for continuous flight. These designs have a 3D printed gear system which makes them a bit more complicated, but brings steering and remote control to the party. If you want one of your own they’re working on a small run of kits. We figure it’d be a lot more fun to prototype and print your own. Sure, it’s reinventing the wheel. But it’s a really cool wheel!
There was a little interest in Graham’s 3D scanning probe, but this is what he is normally using his tiny CNC machine for: manufacturing components for a tiny RC ornithopter. The scale of this thing is amazing. From the tiny gear train to the 0.5mm carbon spars the frame is constructed from. The rudder control only weighs one gram and the entire device comes in at 17 grams.
In a lot of ways, it seems like we’re in the “plateau of productivity” part of the hype cycle when it comes to drones. UAVs have pretty much been reduced to practice and have become mostly an off-the-shelf purchase these days, with a dwindling number of experimenters pushing the envelope with custom builds, like building drones out of dead birds.
These ornithopomorphic UAVs come to us from the New Mexico Insitute of Mining and Technology, where [Mostafa Hassanalian] runs the Autonomous Flight and Aquatic Systems lab. While looking into biomimetics, [Dr. Hassanalian] hit upon the idea of using taxidermy birds as an airframe for drones. He and his team essentially reverse-engineered the birds to figure out how much payload they’d be able to handle, and added back the necessary components to make them fly again.
From the brief video in the tweet embedded below, it’s clear that they’ve come up with a huge variety of feathered drones. Some are clearly intended for testing the aerodynamics of taxidermy wings in makeshift wind tunnels, while others are designed to actually fly. Propulsion seems to run the gamut from bird-shaped RC airplanes with a propeller mounted in the beak to true ornithopters. Some of the drones clearly have a conventional fuselage with feathers added, which makes sense for testing various subsystems, like wings and tails.
It’s easy to mock something like this, and the jokes practically write themselves. But when you think about it, the argument for a flying bird-shaped robot is pretty easy to make from an animal behavior standpoint. If you want to study how birds up close while they’re flying, what better way than to send in a robot that looks similar to the other members of the flock? And besides, evolution figured out avian flight about 150 million years ago, so studying how birds do it is probably going to teach us something.