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Windmill Kit, no longer supplied..  

Turbine Blades

You have several options for windmill blades. I wont go into the details of their design or construction as there is already an abundance of information on the internet about making blades.

The best blades the home builder could make are carved timber blades. With timber you can achieve a near perfect set of blades, but the process is very labour intensive and require some timber working skills, of which I have very little. My first set of timber blades were cut from 18mm ply wood, and shaped into a basic airfoil. They did workgood, but I was then lucky enough to receive a set of carved timber blade my by Dennis Latham of South Australia. These were beautifully finished and have performed better than my own blades. To find out how to make your own timber blades visit Hugh's web site.

There has been some development in using large diameter PVC pipe as blade material. By cutting a PVC pipe lengthways and reshaping the leading and trailing edge with a file, you can achieve a near perfect blade profile, and the process is so simple you could make a complete set of blades is a few hours. You would need some large diameter thick wall pipe, 250mm diameter and 10mm wall thickness. A concern it that PVC is a bit of an unknown for durability. UV light will weaken the PVC and it may shatter, sending sharp PVC splinters in all directions, so a safe operating life of 2 years or less is expected. Dennis ( above ) is also experimenting with PVC blades and is getting good results, I will update this page as his work progresses.

Another option is the use of factory made plastic blades. You can get a set of blades from Michael of EcoInn in New Zealand. He sells a set of 6 blades to make a 1.5 meter diameter propeller for $220 nz. I have a set of these on order and will give them a try.


Blade angles and cord need to be calculated to suit your windmill.
The blade profile is calculated at stations along its length. The diagramme here also shows the blade twist
You can download a blade calculator here. Its an excell spreadsheet so you will need to have Excell installed ( part of MS Office ). The formulae used is based on the work of others, so I cant guarantee its accuracy.
These are the blades made by Dennis before I mounted them on my windmill. They are performing very well.
A set of plastic blades from EcoInn in NZ. Once assembled the propeller diameter is 1500mm

 

If you just want to make a set of simple blades to get your windmill going, click on the image below. It shows how to make a set of blades from 18mm ply wood that might not be as good as properly carved blades, but will work well neverless.

Next - Propeller Hub Assembly