"Output" figures take into account losses based on the efficiencies of pumps or electrical
Note that in graphs 1,2, and 4, the energy input figures are given in "watts per [meter.sup.2]."
The calculation of area is based on the "windswept area," or the total area swept by the rotor, as
you are looking straight at it from the side (as the wind would). Multiply the height of the rotor
by the width at its widest point (the distance in a straight line between the outer tips of a pair of
In graphs 1 and 2 the power per square meter of projected area of S-rotors is plotted against the
wind speed, using test data from seven different sources.Although there are differences, all the
results show that in wind speeds below 20mph the power generation is very small.
For example, the data from Bodek and Simmonds' experimental S-rotor in the West Indies
shows that the useful energy from a 12mph wind imparted into pumped water is 8.5 watts/
[m.sup.2]. This means that one can pump 75 Imperial gallons/hour up to 30' above the water
level (341 litres/hour up to 9,14m).In an 8mph wind the useful energy is only
2.8 watts/[m.sup.2], which means that only 25 Imperial gallons/hour (104 litres/hour) can be
pumped to the same height.
Note that for a 33 percent decrease in wind speed, the water output which is proportional to the
power generated by the S-rotor dropped by approximately 66 percent. The power developed in