Small Wind Turbine Design Notes
Notes based on a session during the Centre for Alternative Technology Windpower Course
Notes written and taught by Hugh Piggott with input from Claus Nybroe.
Hugh Piggott writes:
The first time I did this talk at CAT they threw me in with no preparation, "Just come as you are!"
and I had to wave my arms about a lot. Since then I have done it countless times, but I still get more
than a few blank looks. It's probably the most obscure bit of the course. Finally after about ten
years, I have produced a full set of notes. I am so pleased, I asked Ian to put it on his site, and he
has! Thanks Ian. Sorry I did not explain Betz's theorem, or 'tip speed ratio'. Buy my book
'Windpower Workshop' and read the whole story :)
Content
Defining drag vs lift forces
page 2
Finite element blade design
page 3
The maths of lift and drag
page 4
Setting the best blade angle
page 5
Shape of the apparent wind
page 6
Optimising the chord width
page 7
'Back of an envelope' design
page 8
Factors affecting power coefficient
page 9
Ideal shapes and practical limits
page 10
Pros and cons of high speed rotors
page 11
Variation of size and twist windmill blade
page 12
