On Monday, October 26, 2020 at 11:31:10 AM UTC-5, Nathan Lemmon wrote:
If you're trying to restore your Libelle to original configuration, you might need a SOLLFAHRTGEBER. I have one that is available for sale. If you are interested, email me and I'll send you some photos.

Tony, use google to get examples. There are also a couple of good papers listed from OSTIV the Congresses in 1972 and 1976. Basically it is another way to display speed to fly, similar to McCready theory.