Wind Power is one of the fastest growing of the alternative energy sectors and making your own wind turbine rotor blades is not as complicated as you may think. But before you start cutting up pieces of wood, plastic or metal, make sure that the design of your rotor blades will be correct for the operating speed of your wind turbine generator.
A wind turbines rotor blades are the most highly stressed and vital component of any wind turbine design. Their job is to absorb the kinetic energy in the wind and convert this energy into a rotary motion around a central hub. While the central hub of the blades may be rotating at a gently speed, the tips of the blades are rotating much faster and the longer the blade is, the faster the tip rotates especially for propeller type blades.
When dealing with wind turbines and rotor blade designs, the term “tip-speed ratio” (TSR) is often used instead of blade rpm. The tip-speed ratio is the speed of the rotors tip as it rotates around its circular path divided by windspeed. So for a given windspeed, the higher the TSR the faster it rotates.
Gyroscopic forces are the worst threat to small wind turbine blades as their rotational movement causes them to alternately flap the blades back and forth once per revolution and unless the rotor blades are firmly secured they may fly off. If a blade breaks, and this has been known to happen, it may fly some distance through the air causing damage and injury.
Now that you have decided to make your own wind turbine there are two options available when it comes to deciding on the blades:
- Build them yourself – This is the least expensive option but takes a lot of time and careful work as each blade must be of the same shape, design and balanced.
- Buy premade blades – Buying off the shelf blades costs more but is a lot less work as the design, testing and balancing has been done for you.
Buying Your Rotor Blades
The advantages of buying your rotor blades is that there are hundreds of commercially available blades available to choose from with the most common being the propeller type design. Manufacturers make blades from several different types of materials and although wood was once commonly used to make blades for small wind turbines there are less companies that manufacture blades exclusively from wood. It’s just too expensive and time consuming.
The rotor blades of modern wind turbines are professionally made and are typically made of extremely durable and relatively inexpensive synthetic materials, various types of plastic or composites. Of course there are also disadvantages to buying windmill blades instead of making them yourself with the biggest being cost.
Making Your Own Rotor Blades
While there are many advantages to buying your rotor blades, there are also some big advantages when it comes to building them yourself. The blades you make will match exactly your turbine generator design. You can design and shape your blades to fit your windspeed area making them from a variety of different materials either new or recycled. Wood is the most common DIY rotor blade material as it is easy to cut and shape.
But the biggest advantage of making your own rotor blades is the satisfaction of doing so and that you have saved money. However in reality, by the time you have finish making, painting and balancing your homemade wind turbine blades, the actual cost can be very close to equal if not more than that of premade commercial blades.
So there are advantages and disadvantages of making your own wind turbine rotor blades or just buying them. If you decide to build your own blades, take the time to learn about how to do it easily and cheaply even using recycled materials. Be sure to take the time to design the length, shape and tip speed of your rotor blades to fit your own particular application. Taking the time to learn before you start will ensure that your home made wind turbine operates trouble free for years to come as well as giving you the satisfaction of telling everyone that you did it.