|Windmill Kit, no longer supplied..
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.
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
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
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
- Propeller Hub Assembly