WE POSTED A PICTUE OF A SINGLE SAVONIUS TURBINE. TWO OR MORE CAN BE STACKED. WE SHALL DISCUSS HE ALTERNATOR LATER. LET US LOOK AT HE SAVONIUS TURBINE. JUST LKE THE ANEMOMETER, THE SAVONIUS TURBINE HAS A DRAG PROBLEM. BOH THE FRONT OF ONE SCOOPER AND THE REAR OF THE OTHER SCOOPER FACE THE WIND.THERE IS A DRAG ON THE BACK OF THE SECOND SCOOPER. THIS IS PARTIALLY RESOLVED BY PUTING 3 SCOOPERS SO THAT WSHEN ONE SCOOPER IS FACING THE WIND, THE OTHER TWO SCOOPERS ARE NOT DIRECTLY GIVING HEIR BACKS TO THE WIND. IF YOU CAN IMAGINE THE TURBINE BEING TURNED BY A 6 O'CLOCK WIND,ACTUALLY ONLY SIDE IS AT WORK TURNING THE TURBINE. lET US SAY THE RIGHT SCOOPER FACING THE 6 O'CLOCK WIND. THE LEDT SCOOPER IS IN FACT A DRAG! WHAT IF WE CAN PUT A COVER IN FRONT OF THE LEFT SCOOPER, THEN WE REMOVE THE DRAG. BU WE CANNOT FIX THIS COVER SINCE THE WIND DIRECTION CHANGES. LIKE FROM 6 O'CLOCK, IT MOVES TO 9 O'CLOCK. GHIS IS WHERE THE COVER IS VANED AND ALWAYS MOVE TO WHERE THE WIND IS COMING FROM. IMAGINE YOUR TURBINE INSIDE A CIRCULAR CAGE. AROUND THE CAGE IS SHROUD WHICH COVERS HE DRAG SIDE AND IT PIVOTS AROUND THE CAGE DEPENDIGN WHERE HE WIND IS COMING FROM. IT HAS VANE OPPOSITE THE COVER TOLAIGN THE SHROUD. THIS IS DISCUSSED FOR UNDERSTANDING BU MANY TURBINS IN THE OLD WEST ID NOT HAVE THIS SHROUD AND WORKED WELL. A PICTURE MIGHT BE FOUND LATER ON AND POSTED HERE. WE INTRODUCED THE PROBLEM OF DRAG. MANY DESIGNERS OF THE NEWER TURBINES INTRODUCED SHAPED TURBINES TO MAXIMIZE SCOOPING AND LESSEN DRAG.

ONE DESIGN IS AN OPEN TOP THE SCOOPER TO MAKE THE WIND MOVE UPWARD ALONG THE SCOOPER. AT THE SAME TIME THE AREA OF HE BACK OF THE SCOOPERS IS REDUCED, REDUCING DRAG.