Report KD 656 about rotor with tapered steel blades available

[Adriaan Kragten]

Report KD 656 can be copied for free from my website: www.kdwindturbines.nl at the menu KD-reports. The title of KD 656 is: "Calculations executed for the 2-bladed rotor of the VIRYA-2.92 windmill (lambda design = 6, stainless steel tapered blades) driving the VIRYA-2.68 PM-generator for 24 V battery charging".

Already in 1978 I have measured rotors with tapered blades made out of a cylinder in the wind tunnel. The measurements for a 1.8 m diameter rotor with blades made out of 2 mm stainless steel are given in report KD 616. This report has inspired me to design a bigger rotor with 2.92 m diameter and with blades made out of 3 mm stainless steel sheet and a connecting strip made out of stainless steel strip size 150 * 6 mm. The rotor calculations of the bigger rotor called the VIRYA-2.92 and the matching with the tested PM-generator of the VIRYA-2.68 are given in this new report KD 656.

[Adriaan Kragten]

A new chapter 6 has been added to report KD 656. In this chapter the effect has been researched of using a 0.75 m long connecting strip in stead of a 0.5 m long connecting strip which connects both blades. The diameter of the rotor is increased from 2.92 m up to 3.17 m and the windmill with this bigger rotor is called the VIRYA-3.17. It appears that the same blades can be used and that only the connecting strip has to be twisted 4 degrees in stead of 5 degrees. The Pel-V curve is better for all wind speeds.