We love to see projects revisited, especially when new materials or methods make it worth giving the first design another go around. This twin-turbine vacuum-powered Dremel tool is a perfect example of what better tools can do for a build.
You may recall [JohnnyQ90]’s first attempt at a vacuum powered rotary tool. That incarnation, very similar in design to the current work, was entirely 3D-printed, and caused no little controversy in the comments about the wisdom of spinning anything made on an FDM printer at 43,000 RPM. Despite the naysaying, [Johnny] appears to have survived his own creation. But the turbo-tool did have its limitations, including somewhat anemic torque. This version, machined rather than printed and made almost completely from aluminum, seems to have solved that problem, perhaps thanks to the increased mass of the rotating parts. The twin rotors and the stator were milled with a 5-axis CNC machine, which has been a great addition to [JohnnyQ90]’s shop. The turbine shaft, looking like something from a miniature jet engine, was meticulously balanced using magnets mounted in the headstock and tailstock of a lathe. The video below shows the build and a few tests; we’re not big fans of the ergonomics of holding the tool on the end of that bulky hose, but it sure seems to work well. And that sound!
We first noticed [JohnnyQ90] when he machined aluminum from soda cans to make a mini Tesla turbine. His builds have come a long way since then, and we look forward to what he’ll come up with next.
Followers of the Church of Elon will no doubt already be aware of SpaceX’s latest technical triumph: the test firing of the first full-scale Raptor engine. Of course, it was hardly a secret. As he often does, Elon has been “leaking” behind the scenes information, pictures, and even video of the event on his Twitter account. Combined with the relative transparency of SpaceX to begin with, this gives us an exceptionally clear look at how literal rocket science is performed at the Hawthorne, California based company.
This openness has been a key part of SpaceX’s popularity on the Internet (that, and the big rockets), but its been especially illuminating in regards to the Raptor. The technology behind this next generation engine, known as “full-flow staged combustion” has for decades been considered all but impossible by the traditional aerospace players. Despite extensive research into the technology by the Soviet Union and the United States, no engine utilizing this complex combustion system has even been flown. Yet, just six years after Elon announced SpaceX was designing the Raptor, they’ve completed their first flight-ready engine.
The full-flow staged combustion engine is often considered the “Holy Grail” of rocketry, as it promises to extract the most possible energy from its liquid propellants. In a field where every ounce is important, being able to squeeze even a few percent more thrust out of the vehicle is worth fighting for. Especially if, like SpaceX, you’re planning on putting these new full-flow engines into the world’s largest operational booster rocket and spacecraft.
But what makes full-flow staged combustion more efficient, and why has it been so difficult to build an engine that utilizes it? To understand that, we’ll need to first take a closer look at more traditional rocket engines, and the design paradigms which have defined them since the very beginning.
It is three weeks after the apocalypse. No zombies yet. But you do need to charge your cell phone. How do you quickly make a wind turbine? If you’ve read this project, you might reach for a few empty water bottles. This educational project might not charge your phone without some extra work, but it does illustrate how to use water bottles to make a workable air scoop for turning a crank and possibly generating electricity.
That takes care of the wind and water aspects, but how did we get solar? According to the post — and we agree it is technically true — wind power is a form of solar power since the wind is driven by temperature differences created by the sun. Technically true!
[Integza] built a Tesla turbine and wanted to know how fast it was spinning. However, he didn’t have a tachometer, and didn’t want to buy one. After a false start of trying to analyze the audio to measure the speed, he decided to use a tried-and-true method. Let the wheel break an infrared (IR) optointerruptor and count the spokes of the wheel as they go by. If you know the spacing between the spokes, you can compute the speed. There was only one problem: it didn’t work.
Turns out, PLA is at least somewhat transparent to IR. Knowing that it was a simple matter to fix some tape to the wheel that would block IR and that made things work much better. If you missed the video where he built the turbine, you might want to watch it first.
Wind turbines are great when the wind flow is predictable. In urban environments, especially in cities with skyscrapers, wind patterns can be truly chaotic. What you need, then, is a wind turbine that works no matter which way the wind blows. And just such a turbine has won the global first prize James Dyson Award. Check out their video below the break.
The turbine design is really neat. It’s essentially a sphere with vents oriented so that it’s always going to rotate one way (say, clockwise) no matter where the wind hits it. The inventors say they were inspired by NASA’s Tumbleweed project, which started off as a brainstorming session and then went on to roll around Antarctica. We tumbled into this PDF, and this summary report, but would love more info if any of you out there know something about Tumbleweeds.
Back to the turbine, though. How efficient is it? How likely is it to scale? How will a 3D-printed version drive a junk-bin brushless motor on my balcony? The jury is still out. But if a significant portion of the wind comes from otherwise unusable directions, this thing could be a win. Who’s going to be the first to 3D print one?
There was a time, not so long ago, when hype for desktop 3D printing as so high that it seemed you could print anything. Just imagine it, and your handy dandy magical 3D printer could manifest it into reality. But now that more people have had first hand experience with the technology, the bubble has burst. Reality has sobered us up a bit, and today we’ve got a much better idea of what can and cannot be printed on a traditional desktop 3D printer.
But that doesn’t mean we aren’t surprised from time to time. As a perfect example, take a look at this almost entirely 3D printed wind turbine designed and built by [Nikola Petrov]. Outside of the electronics, the pole it’s mounted to, and some assorted bits and bobs, he produced all the parts on his own large-format TEVO Black Widow printer. He mentions there are a few things he would do differently if he was to build another one, but it’s hard to find much to complain about with such a gorgeous build.
To be sure, this one isn’t for the 3D printing novice. First of all, you’ll need a printer with a bed that’s at least 370 mm wide just to print the blades. [Nikola] also recommends printing the parts in ABS and coating them with acetone to smooth and harden the outside surfaces. We’d be surprised if you could print such large objects in ABS without a heated enclosure as well, so plan on adding that to your shopping list.
On the flip side though, the electronics are about as simple as they come. The blades are spinning a standard NEMA 17 stepper motor (through a 1:5 gearbox) to produce AC power. This is then fed into two W02M rectifiers and a beefy capacitor, which gives him DC with a minimum of fuss. In theory it should be capable of producing 1A at 12V, which is enough to light LEDs and charge phones. In this design there’s no battery charging circuit or anything like that, as [Nikola] says it’s up to the reader to figure out how to integrate the turbine into their system.
What’s great about the Power Generation Modules project headed by [Cole B] is the focus on usability and modularity. The project is a system for powering and charging small devices using any number and combination of generator modules: wind turbine, hand-crank, and water turbine so far. Power management and storage is handled by a separate unit that acts as a battery bank to store the output from up to six generators at once. There’s also a separate LED lamp module, designed to be capable of being powered directly from any of the generator modules if needed.
The hand crank is straightforward in concept, but key to usability was selecting a DC gearmotor with a gear ratio that made cranking by hand both comfortable and sustainable; too weak of a crank and it’s awkward, too hard and it’s tiring. The wind turbine has three compact vanes that turn a central shaft, but testing showed the brushless motor it uses as a generator isn’t a good match for the design; the wind turbine won’t turn well in regular wind conditions. The water turbine prototype showed great success; it consists of an epoxy-glazed, 5 inch diameter 3D printed propeller housed in a section of PVC pipe. The propeller drives a brushless motor which [Cole B] says easily outputs between eight to ten volts when testing in a small stream.
The team has plans for other generators such as solar, but this is a great start to an array of modules that can be used to power and charge small devices while off the grid. We’re happy to see them as a finalist for The Hackaday Prize; they were selected as one of the twenty projects to receive $1000 cash each in the Power Harvesting Challenge. The Human-Computer Interface Challenge is currently underway which seeks innovative ideas about how humans and computers can interface with one another, and twenty of those finalists will also receive $1000 each and be in the running for the Grand Prize of $50,000.