Morning all,
well it is here in Scotland
many thanks to all who posted reply's way back in February and for those who may be interested here' how I got on.
I went ahead as planned with the three pennstocks at different heights in the header tank as planned
http://www.navitron.org.uk/forum/index.php/board,11.0.html The first at 40mm internal the second at 50mm and the third at 90mm each one feeding a different nozzle on a high voltage 'Stream Engine'. I commissioned the system about a month ago after a dry spell and with flow down to 6.3gpm .4lt/sec which after a little playing about with nozzles and adjusting the field gave me about 100w from 130' 40m of head.
When the second nozzle comes into play it gives around 300w and the third 800w as pointed out there is a little loss of efficiency when one pipe is not fully filled but it's not a great deal and the autonomy of the system more than.
It's early days yet but we've had a good variety of flows down the stream and so far I'm well pleased with it, I'm sure that I could get more output by adjusting the field at the higher speeds but like I said I'm striving for an automatic system.
I've been taking power output readings twice daily and as soon as I can figure out how to do a graph I'll post results.
Cheers, Paul