The Vertical Axis Wind Turbine (VAWT) Challenge
"This is a 340mm diameter prototype VAWT that's intended to be a scalable demonstrator. It accommodates 3 blades which are stolen directly from scrap vinyl vertical blinds. (Yes, those ugly fat ones that hang) You just take the single blinds and insert them in to the slots. I put a dab of 2-part epoxy to keep them in place, but the fit is tight. The blade arms attach via 3x 3mm screws or bolts.
The Challenge: Take Justin's design and print the wind blade arms and hub on your 3D printer using the STL files available for downloading at at http://www.thingiverse.com/thing:85168. Build a working model including small generator and some method of displaying power output. Improve this working model by redesigning the hub to accommodate 6 blade arms. Provide the STL and source CAD files so that others can build on your success. Your reward: one of three WI-FI enabled iPad Minis valued at $350.
Note: Only Maine middle and high school teachers and students are eligible to participate. A small panel of techno wizards will verify that you've qualified for this award. Challenge ends February 1, 2014, or when the three Minis have been awarded. Please contact Dave Perloff to indicate your interest in being a challenge participant.
VAWT assembly.
Blade arm.
VAWT assembly with small generator.
VAWT assembly.
"In the old days, explained Iorio, when G.E. wanted to build a jet engine part, a designer would have to design the product, then G.E. would have to build the machine tools to make a prototype of that part, which could take up to a year, and then it would manufacture the part and test it, with each test iteration taking a few months. The whole process, said Iorio, often took “two years from when you first had the idea for some of our complex components.”
Today, said Iorio, engineers using three-dimensional, computer-aided design software now design the part on a computer screen. Then they transmit it to a 3-D printer, which is filled with a fine metal powder and a laser device that literally builds or “prints,” the piece out of the metal
powder before your eyes, to the exact specifications. Then, you immediately test it — four, five, six times in a day — and when it is just right you have your new part. To be sure, some complex parts require more time, but this is the future. That’s what she means by complexity is free.
“The feedback loop is so short now,” explained Iorio, that “in a couple days you can have a concept, the design of the part, you get it made, you get it back and test whether it is valid” and “within a week you have it produced. ... It is getting us both better performance and speed.”
Reprinted from "When Complexity is Free" by Tom Friedman, New York Times, September 14, 2013:
http://www.nytimes.com/2013/09/15/opinion/sunday/friedman-when-complexity-is-free.html
The central hub is sized to use a 7/16 shaft (I use 1/2" threaded rod that's cut down with a lathe in just the right place so I can put a 1/2" nut below to support the turbine). Note that there's a 20-tooth gear face on the hub, if you'd like to drive a mechanism - though I doubt you'll power more than landscaping lights until this is optimized. That being said, I have included the solidworks part files so that you can change the blade angle, etc. if you'd like. Oh, and you could print more than one set and drive a multi-tiered version with really long blinds if you like!"
Justin Karl
Aerospace Engineer
Orlando, Florida
