@Peter H
Thank you very much !
My books effectively are
"Ergebnisse der Aerodynamischen Versuchsanstalt zu Göttingen"
Different "Lieferung" !
Congratulations for all these references I will read again 30 years after I discovered them (I was only begining to feel me allowed to have a critical analysis of official aerodynamics theory)
Without surprise I already found something wrong
we discussed in the Thread about Lift !
We have to sort what is worth from these old studies who were forgiven with dispersion of german scientists : someone had to fly away nazism, others have been made prisoners and worked on other subjects.