Wind energy isn’t quite as common of an alternative energy source as solar, at least for small installations. It’s usually much easier just to throw a few panels and a battery together than it is to have a working turbine with many moving parts that need to be maintained when only a small amount of power is needed. However, if you find yourself where the wind blows but the sun don’t shine, there are a few new tools available to help create the most efficient wind turbine possible, provided you have a 3D printer.
[Jan] created this turbine with the help of QBlade, a piece of software that helps design turbine blades. It doesn’t have any support for 3D printing though, such as separating the blades into segments, infill, and attachment points, so [Jan] built YBlade to help take care of all of this and made the software available on the project’s GitHub page. The blades are only part of this story, though. [Jan] goes on to build a complete full-scale wind turbine that can generate nearly a kilowatt of power at peak production, although it does not currently have a generator attached and all of the energy gets converted to heat.
While we hope that future versions include a generator and perhaps even pitched blades to control rotor speed, [Jan] plans to focus his efforts into improving the blade design via the 3D printer. He is using an SLA printer for these builds, but presumably any type of printer would be up to the task of building a turbine like this. If you need inspiration for building a generator, take a look at this build which attempted to adapt a ceiling fan motor into a wind turbine generator.
>> if you find yourself where the wind blows but the sun don’t shine
OK, I’m pretty sure there’s a joke in there somewhere…
Maybe if hell frises…
I’m sure you could “work it out with a pencil”…
>> I’m sure you could “work it out with a pencil”…
Ouch!
I was thinking that if you’re where the wind blows but the sun don’t shine, bio-methane might be your first choice for alternative energy.
“perhaps even pitched blades to control rotor speed”
Although most of my experience with marine props, those blades looks “pitched” already, perhaps the author means “variable pitch blades”.
All this 3D-printed stuff should only be posted if the parts survived at least 6 month continuously in real use.
In this specific case, the whole thing is very bad idea.
Wind turbine blades are made to aerospace standards for a reason.
What do you think will happen to this guy’s wind turbine? I’m not familiar with resin printing, so I don’t really know how tough it is, but I can’t imagine a blade 3D printed in the SLS printer I have access to failing very easily. Is resin that much more fragile? Does it just fall apart when exposed to any moisture? It’s not like this thing will be in a horribly demanding environment, if there’s a windstorm and a branch smacks it he can print another blade.
No matter which printer technology you use to make a prop like this, you’d want to have a good understanding of the material you use and how it will withstand UV, water exposure and so on.
You really wouldn’t want a prop like this to become brittle and fly apart at high speed.
Spoil sport! Lol
It’s only likely to suffer in uv light or moisture if you print it with PLA or resin. Most printers can print in materials like nylon that are much more robust.
He did paint it, so UV exposure probably won’t be an issue.
Water, maybe. I dunno. I don’t see why people are slamming on it, though, he won’t lose much if the blades don’t last. He’d just have to farm out their replacements’ print from a more robust printing method from a shop.
It’s not hard to overcome this. Simplest solution, cover it in resin. You could also wrap it with a fiber with some resin. With all 3d printing you have to test and then you can modify it after.
I don’t think he’s using it as an airplane prop.
You do know there are a full range of engineering resins available now.
Consider the blade RPM, weight, and thus momentum if they break in a windstorm.
I was peripherally involved with the cleanup after a 4 foot commercial wind turbine failed during a gusty storm. It used removable glass-reinforced removable nylon blades (it was a portable/expedition model; everything could be turned into a 4 foot by 2 foot bundle, including the 20 foot pole), and one of the blade locks failed. The weather station mounted to the same pole indicated 27 mph sustained, with gusts to 56, which was the last datapoint recorded before the spontaneous disassembly.
The blade separated at the worst possible angle, and was driven down through a tent, through both sides of a large plastic cooler full of flint glass bioassay containers packed in dry ice, and embedded itself six inches into hard-packed clay.
If it had failed fractionally earlier in the rotation, it would have pinned a sleeping bag full of biologist to the ground. Said biologist was a bit shell-shocked and kept telling anyone who would listen that the human thorax was certainly no harder to penetrate than a plastic cooler. The nearest trauma center was several hours away, even if a careflight could be arranged…
One of the other blades ended up a little over 100 feet away.
(I wasn’t present, but had to deal with some of the damaged equipment, and everybody insisted on showing me all the photos and telling the story, repeatedly…)
The blades in the article are probalby lighter than glass-reinforced nylon, so wouldn’t have so much momentum and would slow down faster. But they’re also far more likely to fail, at much lower stress, and the failure probability will increase rapidly based on duration of outdoor exposure. Even if the paint totally blocked UV (it never does), most of these materials tend to get brittle after experiencing repeated day/night thermal cycles.
According to the Otherpower guys, they’ve seen 1.5 inch steel pressure pipe “bend like a pipe cleaner in 50 mph winds, under a wind machine with only an 8-foot rotor”. That energy gets converted to rotation by the blades, and even aluminum-reinforced blades can fail if the generator doesn’t manage to furl in time to avoid the rpm spike.
The portable wind generator failure surprised everyone because they had expected the 20 foot tower to be too short to get into really clean air. They were correct, this really limited their power output… but turbulent air can actually put greater stress on the blades, since they’re constantly changing rpm and bearing. The blades act like any gyro, so bearing changes also produce torque on the blades, adding to the stress. The gust that killed the turbine (and nearly the biologist) also saw a 60 degree bearing change in under 30 seconds, which appeared to be the real final straw that broke the blade.
I was just killing time, wandering across the web and came on to this article. And now I’m really enjoying everyone’s comments, especially the blade failure story! I’m a field scientist who studies dust devils and am very impressed by what the wind does to our meteorology towers and anemometer sensors. Gear failure due to wind fatigue is a constant problem. Like rust and gravity, wind never sleeps although it does take the occasional nap. I’m delighted all of you are turning your fascination with 3D printing into applied technology for real world applications. Best wishes
Variable pitch blades would solve the problem of spooling up, and counter-rotating blades would solve the second. The only problem to solve would be the torque generated between the sets of blades
Dad made a wind turbine from an oil drum. That didn’t blow sort for decades- in the derecho of 1985. Just old truck parts welded between the the silos.
Aerospace standards? Don’t tell these people… https://otherpower.com/otherpower_wind.html
The Dutch had been making effective windmills that to this day still stand over 300 years ago out of wood and cloth.. this modern-day aerospace materials that are impossible to recycle overly expensive over engineered and utterly a problem when you are talking about rapid field deployment in low knowledge or hostile regions that need power… Less silicon valley and more Somalia…
A thin carbon fiber fabric sleeve laid with UV resistant epoxy wouldn’t add much weight, and would probably outlast the Generator…
If you are going to go to that length why not use 3d printed formers for the fibreglass/carbon fibre wings so they can be way way lighter and probably stiffer and stronger than just a wrapped 3d print too.
Actually, that was my next thought. Just spar it!
Automation breed complacency, why use a generator, when you can recover twice as much energy using a water pump?
Gear pump design, wind turbine front and rear, to equalize torque. They would be off set by the gear pump width (front/rear) counter rotating. Concentric off-set by the gear pump shaft centers, smaller set upper shaft. This allows and ‘air duct’ to fill the void, by the offset.
Fluid friction eats most of the theoretical energy gain, and electrons are much more convenient to herd.
The trailing blade undergoes very bad “cogging”, with constantly changing bending force each time it passes through the leading blade’s wind shadow.
And it’s much harder (but not impossible) to keep such a design automatically and passively faced into the wind.
You would have to design to achieve much lower RPM in your target wind, or else you’d need significant step-down gearing between the blade and the water pump to avoid stalling the blades. Once the blades are moving too slow for the wind, substantial turbulence forms across their backs, causing a rapid loss of torque. Rather than using generator-turbine blade profiles, a water pump often more from sail-profile blades (classic windmills _are_ water pumps, and grain mills have similar torque requirements to water pumps). However, both of these classic designs intentionally oversize the mill to ensure sufficient starting torque. And, by not using airfoils, they cap the rpms achieved in a given wind, which is actually helpful in such a role.
It would be a good solution if you had the right problem, but is much less generally applicable than the normal small wind generator arrangement.
Thank you for the response, and yes, turbulent flow friction can reduce efficiency quickly. The design envisioned would use ‘supports’ or even ‘compressor’ blades to negate wind shadow. As opposed to a single pump, there would be three stages varied by input/discharge valves. All valves closed would halt the blades (ebrake). Fuidics can be used for actuation, as opposed to servos. The primary purpose of balanced forces, is longevity.
The trade offs are for a specific application, NAWAPA, aka moving river flow to a higher elevation. Much of the water will be moved along ridge lines, which tend to have significant natural wind turbulence. In addition, the tower bases themselves will be water tanks.
IMO, it will be easier to get ‘water rights’ over legal district lines, if done on a more natural level ie no electricity nor use of hydrocarbons. The excess power can be recovered down stream, closer to it’s location of uses. While the transformer is highly efficient, generators are still only fifty percent of input energy.
Much of the energy produced, may have to be used for UV sterilization, as evasive species can cause problems ie Zebra mussels, Asian carp.
Once principals are established, we may need to dump more CO2 in the atmosphere, as vegetation will be growing exponentially.
Could use a windmill like this intentionally for heat generation – https://www.lowtechmagazine.com/2019/02/heat-your-house-with-a-water-brake-windmill.html
One of the biggest problems of a single blade failure in high winds is the resulting extreme unbalance. That is the usual failure mode including tower failure and pulling out of the guy wires from the ground (if used). From my experiences a a windmill engineer designing controls and instrumenting machines with strain gauges, power monitoring and wind resource data logging, I’ve seen my share of failures. It’s been a while so my experience was with relatively small 40 to 250 KW rated machines. We had lots of them so when we had a failure in one, it was just a failure. Systemic failures in several gave us a lead on the weak points that we could apply some real analysis. Little ones like the one described are essentially toys unless the load demand is very well defined such as the ones on sailboats. Scaling up quickly runs into some real problems.