This is my second guide on wind turbine blades. My experiences with low-cost solutions have not improved. This time I am talking about those small "carbon fiber" wind turbine blades that are sold predominantly by a seller named Qaz. They are intended to replace Air-X blades and can also be used to drive other wind turbine generators, including the "Hornet"  that Qaz sells. I am putting carbon fiber in quotes, because these blades are not what you might expect. Any structural, aeronautical, naval, and automotive engineer would agree with me stating that true carbon fiber is a material used to make light structural components of extreme tensile strength. Sounds great, and it's all true. Carbon fiber revolutionized construction of aircraft and automobiles, to mention only a couple examples. To be strong, carbon fiber is used in a lay-up process, in which carbon fiber cloth is "wetted out" or infused with epoxy resin and then often vacuum-bagged to maintain proper shape, thickness and structure of the new part. Often, composites are made using glass or kevlar in conjunction with carbon. A lay-up process is also used in the construction of the fuselage and other parts of the new Boeing and Airbus aircraft, for example. That is how carbon fiber is properly worked with, and you better trust the know-how when you step into that plane next time.

Now to these blades. They are NOT carbon fiber in the traditional sense. While Qaz claims that these blades contain 50% fiber by weight (maybe, maybe not), they are NOT produced using the lay-up process described above and they are NOT as strong and long-lasting as the description proclaims. Firstly they are produced using cavity moulds into which plastic (probably polypropylene) is filled. The plastic may contain carbon powder or shreds at the best, which becomes obvious once one or all of the blades fail. There are no fibers to hold anything together. The fracture point looks like any porous old plastic (see picture). Those of you who live in colder climates (say Canada, like me) know that plastic gets really brittle in cold temperatures. In cold temperature these blades lose their flexibility and snap off like icicles from your gutter! Knowing this, would you step in to a "carbon fiber" Boeing going up to 33,000 ft and -40 degrees? Of course you would, because you know that real carbon fiber is made DIFFERENTLY! Depending on the wind speed while losing a blade, you could encounter a devastating failure of you entire system. An unbalanced rotor spinning at 1500 RPM or more means trouble. I found blades over 300 yards from where the turbine was. You can imagine how fast these were and you can imagine what could happen if they were to hit a person. Of course Qaz claims that the failure was due to operator related issues and the "contraption" (how he puts ist) these blades were mounted to, however, it was a "Hornet" generator. He also claims that Hornet generators have an induction brake to slow down the rotor and prevent overspeed. My question is, how does that work, if 1) the Hornet does not use a charge controller with heat sink, 2) the batteries are fully charged, 3) there is no flow of current to generate the back-EMF in the generator? I am planning to write another guide on back-EMF brakes in wind turbines. Be patient.

So listen to this: Don't waste your money and prevent damage to life and property. Ask yourself thrice whether you really want to buy those blades.