At this time of year I had hoped that rain would have been increasing the flow and that I could have done the measurements at each increase in nozzle size with little inconvenience; there being no rain, no increase in flow and no call to increase nozzles, all I could do was measure the smaller nozzles one after the other in a single blitz of measurement.
It made for a lot of exercise up and down the hill between turbine and header tank, - and for an interesting record in the on-line power trace:
The results of the experiment are presented in the following graph; on it I have also indicated the flow each nozzle delivered, as determined by measurement:
Thus far so good: - from now on I will take 0.85 to be the discharge coefficient. In time there will be opportunity to take measurements for the larger nozzles VIII to XII and when available these will add weight to the picture so far obtained.
Does all this cause the earth to shift on its axis of rotation ? - no but it's still worth investigating !
**later I discovered this nozzle was badly cut explaining why it was different.
Addendum dated 2 Feb 2017
Today copious rain has made it possible to measure the Cd and flow of the remaining 5 nozzles; the results are shown in the revised chart below; overall the Cd of EcoInnovation nozzles on my site seems to be 0.85 ± 0.01.