Brian's Morning Newsletter
Thursday, July 14 2011
Our expression of Climate Change has been a terrible drought. We've not only not had any rain in the year 2011, but constant high winds have been fanning wild fires all over the state of New Mexico.This has been a tough year. My father Henry Seay Rodgers died February 28th 2011 Henry's obit We as a family ,did home hospice and Henry died peacefully. Nevertheless, it is still very hard on Clara, my mother, and we're doing the best we can.
High gusts of wind slightly bent the top piece of our wind turbine tower early in the year. We had build a new set of blades last Summer using Louie's CNC router with Kevin Murphy designing and implementing the blade set. I had decided that with the doubling of the battery capacity it might be a good idea to lengthen the blade by six inches. That decision changed critical mechanical dynamics of the turbine, causing it to be unable to furl quickly in high gusts, which in turn put extra pressure on the tower top.
When I pulled the turbine down I noticed the alternator was discolored in places likely from heat, a second consequence of adding blade length. The area of air the blades cover is called "Wind Swept Area." pi x Radius² = Area Swept by the Blades.
Here is a description of wind swept area from a Down Under alt power forum called Back Shed
While I was building a new stator for our permanent magnet alternator Louie moved his CNC router to David Old's Old Wood Flooring industrial wood working shop in Dee Bibb industrial park in Las Vegas. All I can claim credit for was making the connections between the guys, although I don't mind saying it was no small feat.
Kevins-July-2011-blade-set – The wood is Western Red Cedar. I guess I did do something besides stand by while Kevin designed and created the blades on the CNC Router I got a complement from David that the lamination of the blade blanks was real fine work. Oh how I love complements especially from a guy like David, a professional in the wood business, thank you <bowing>
Kevins-July-2011-blade-set – Kevin's work really paid off. The blades are gorgeous, with graceful curves and long slender lines. David Old said he was proud to have these blades in his shop. I don't think he really wanted to give them up, hehe. So I strategically used that moment, to ask him to set aside some special Douglas Fir milled and kiln dried wood which is what Old Wood Flooring is famous for and Kevin could cut blades until the cows came home.
Kevins-July-2011-blade-set – From the side perhaps you can see the blade curve about two thirds of the way toward the tip. Kevin suggested this should help keep the slender, thus more flexible tips away from the tower
Kevins-July-2011-blade-set – I hope a picture is worth at least a dozen words. Above you are looking at the base of the blade. Beautiful. Incredible job Kevin.
Kevins-July-2011-blade-set – The base. These blades should be fast fast fast. Oh and the term here is Tip Speed Ratio or TSR
Kevins-July-2011-blade-set _ here you should be able to se the slight bend outward of the blade. It is a little exaggerated by the camera, not to mention me trying to suck my gut in so the picture was not all belly. The actual offset is less than the thickness of the blanks, or 1.75 inch.
Kevins-July-2011-blade-set I can't wait. Today we'll start cleaning up the knife edge and removing any machining marks left by the router. Now that we've got all the elements of the homemade wind turbine together we should be able to crank out more blade prototypes for testing on our axial flux permanent magnet wind turbine