I am watching the men who are laying the drains in the road. They have a 50 gallon drum which they have diesel oil. Some times they tend to forget them. This will make a real ‘biggie’. I like the Savonius as it is self starting and is Omni-directional. They are low speed but high torque so I cannot easily use centrifugal pumps without gearing. The Downton pump was made from old Dog-nosh tins running up a 3 meter long bit of plastic down-spout pipe and are pulled by bits of old bicycle chain (the local bike shops are now convinced that the English are total nutters). The pump leaks back into the sump when it is not running, this makes for easy starting.  It coes ‘cluttr cluttr’ etc when it is pumping
Dick

Edited By Richard Parsons on 23/07/2010 15:50:45

There’s an interesting research document about that here.

The problem with the Savonius Rotor is that they are slow and low powered. They are cheap, easy to build, omni-directional and unlike the Darrius rotor are self starting. My pump gives me about 10 watts in a 6M/Sec wind it pumps about 40 litres/hour.

The overlap on the drums is variously 25 to 10% according to various authorities. It is a good idea to Google for Savonius rotor power output. It gets rid of the junk.

I once built two from dog food cans to get rid of moles in someone’s lawn. They had a little clicker on them which transmitted noise into the earth. Old Molewarps don’t like noise as he cannot hear the wyrms. A few days of that and they packed their bags and went elsewhere.

Ole Moliwarps does not like noises. And the constant clicking drives them to despair.  Try it one day.  If 2 moles meet ‘out of season’ within a few hours you have one a very fat mole.