The stealth VAWT is an aesthetically pleasing vertical axis wind turbine.
I didn’t name it stealth vawt because it’s invisible to radar. I call it a stealth vawt because it’s more aesthetically pleasing than your average horizontal axis wind turbine. And when mounted on you roof ridge may not draw any more attention than an attic ventilator spinning in the breeze. On the other hand it is very easily seen by birds and would be virtually impossible for a bird to injure itself by flying through it. That is a major issue for bird lovers like myself. I’m not a bird watcher, I just don’t want to be the cause of any bird fatalities.
I built small models first
My very first attempt at building a VAWT was based on a model I designed to turn using only the breeze coming from a small air purifier. The little guy had aluminum blades I cut from energy drink cans. Each blade was hinged at the top and bottom to allow the blades to open into the wind which would maximize each blades exposed area when the wind blew against it. The blade would then close again to reduce the wind resistance when the wind hits the outward facing side of the blades. The blades were mounted to upper and lower rims which were connected to a center shaft by spokes. You can see that model in this video I uploaded to YouTube back on January 4 of 2009. It’s the little floppy bladed spinning thing on the right.
I did attempt to build a full sized version of that model, but it didn’t work out very well. When the wind caught hold it, the clatter it made was terrible. Below is the only photo of the full sized floppy bladed wind turbine that I kept.
I took this photo after the final modification to mute the horrendous noise it makes when running failed. This was shortly before I cannibalized this turbines parts for other projects. I haven’t abandoned this idea completely, but I have eliminated this particular configuration due to its noise factor. I do plan to revisit this movable blade idea again in the future using another design and with lighter, less noisy materials.
Stealth VAWT model & magnetic thrust bearings
On the left side of the video above, you might have seen the model for the stealth turbine. That model was made from a few blades I removed from the floppy bladed turbine after disassembly. If you look close maybe you can see that the miniature stealth vawt model has an interesting feature not built into the full size versions. It uses two speaker magnets set to oppose each other which essentially creates a magnetic bearing. I have tinkered with the idea of magnetic bearings for the full sized vawts, but until I’m certain of the style and brand of generator I intend to use, that project will stay on the back burner. Here is a photo of a pair of ring style neodymium magnets and the mounting plate that I had made to use with the WindBlue PMA before I decided against using it for the stealth vawt.
For the moment I prefer using the Freedom II permanent magnet generator made by Missouri Wind and Solar as a match for my wind turbines. But that too is subject to change if I should find another PMA/PMG with similar attributes at a more affordable price.
Tweak & Tweak Again
The turbine itself has changed from a small toy into an actual wind powered generator and has continued to be improved as the opportunities for improvement have presented themselves. I’m constantly trying to tweak this little turbine to improve torque and speed. To see how the turbine has progressed so far, you can view this video and the series of upgrades.
I do have another design improvement in mind. The idea is to make the blades longer at bottom which will extend them below the PMA and put the bearings of the PMA closer to the center of the turbine. The longer blades will catch more air, and having the PMA closer to the centerline of the turbine should put less strain on the bearings. So in order for the turbines design to be changed, the tools i’m using to build them must change as well.
Welcome the new sheet metal brake.
This new brake has a maximum width of 48 inches or 1.2192 meters. And I’m looking forward to making the next generation of stealth vawt blades. Money has been really tight lately, so I haven’t had the funds to move forward on this project in a while. But once I can afford to buy the next batch of materials, I will post new information and videos to this page. I believe this will be the final major upgrade to this design. And once I’ve tested it a bit I hope to have plans available to you on the Project Plans page.
Please check back from time to time to monitor the progress
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