Report KD 491, originally written in March 2012 but reviewed in October 2018, has been made public and added to the list of public KD-reports. The title of this report is: “Research of the usability of the Solaflux solar pump with a 2.6 mm cam in combination with the VIRYA-3B3 windmill. The Solaflux pump has been tested already in 2003. The use of this pump in combination with the VIRYA-3D windmill is described in the Dutch report KD 114. However, the VIRYA-3D windmill with steel blades is cancelled and in KD 491 it is demonstrated that this pump can also be used in combination with the VIRYA-3B3 windmill with wooden blades.