hi karsten,

I finally made some progress understanding that bug. I think ultimately nothing is going to change as far as for you. I just need to make some changes so the analysis is correct. Unfortunately, understanding the angles is pretty difficult. More so than I thought. I will have to make some pictures and things to try and explain it for the documentation. But basically the total sweep angle is measured in the top view (x-y). It would be about the local z axis of each cross section. In the videos I was saying the global z axis but that's not the case. So if you are using the total sweep angles from the file that is how to use them. I will have a new version of PROP_DESIGN out at some point but I don't think it will change much from what you are seeing and dealing with.

although on second thought. I can now compute the total sweep angle at the aerodynamic center. so I can output it as well. that may fix the whole mess of different reference points. In that case, you could measure everything from the ac. which is how it's supposed to be. i'll see about doing that. not sure what will happen. but i'll get back with you.