I am 71 years old now and in December 2017 I have ended the commercial activities for my engineering office Kragten Design. But I am still active and my website: www.kdwindturbines.nl will be maintained as long as possible. In the first half year of 2018 I have written five new free public KD-reports. Four of these reports give rotor calculations. At the menu “News” on my website you find a short description of the content of each report. At the top of the menu “KD-reports” there is the folder: “List free public KD-reports” and the folder “Sequence of KD-reports for self-study” which, I think, will be of great help for someone who wants to design a wind turbine.
Thanks Adriaan. This is a wonderful resource for students of wind turbine design. Here is a chart from KD35 showing the relationship between conversion “efficiency” and drag/lift ratio, over a range of tip speed ratios: