Report KD 634 has been cancelled and is replaced by KD 652 and KD 653. The title of KD 653 is: Development of the VIRYA-3.6, a windmill with a Polycord transmission in between the rotor shaft and the vertical shaft to drive a standard centrifugal pump. KD 652 gives the calculations of the 4-bladed VIRYA-3.6 rotor.

The VIRYA-3.6 has a 15 mm round Polycord string in the tower top with an accelerating gear ratio of 2.5 : 1. At the bottom of the vertical shaft there is a rectangular gear box with an accelerating gear ratio of about 4. The gear box is flanged to a standard low head 1-step centrifugal pump which can be used for drainage or for low head irrigation.