The cost of living... what can we do?

I spent about ten minutes trying to insert the necessary mathematical symbols in then gave up

EDIT. I think we're both wrong. I knew I was wrong so I googled it. It's pi r squared.

 

That's the swept area, isn't it the surface area of the aerofoil that the wind acts on that is important, rather than simply the diameter of the turbine.
My maths has never been up to calculating the area of a complex 3d curved shape.
Can do pizza though: 2 by 6" pizza; surface area of top = 28.2 x 2 = 56.55 sq in.
1 by 12" pizza surface area of top = 113.1 sq in.

 

Sorry talking out of my rear again; a bit of research (google) shows it is the swept area.
"The equation for wind power(P) is given by P= 0.5 x ρ x A x Cp x V3 x Ng x Nb where, ρ = Air density in kg/m3, A = Rotor swept area (m2). Cp = Coefficient of performance V = wind velocity (m/s) Ng = generator efficiency Nb = gear box bearing efficiency."
Found this page interesting, shows maximum efficiency ~ 59.3 %.

 

I knew that but didn't want to be picky.
I'm guessing that the 2 crept in because it's the usual way to writing squared.

 

Last line, efficiency, does that mean any size of rotor is 59.3% efficient?

 

Shouldn't the 2 be a smaller one ,when i was at school that would indicate pi x r x 2.

 

Used to write pi x r^2

 

When i was at school pi = meat & tattie.

 

59.3% of something for nothing is great. If someone was giving away £1M but they were only giving me 59.3% I would be delighted.

 

Just got my last months Gas and Electric bill.
£68, month before was £98 so the £66 from the government is working for me.