doc: add warning for Caradonna errors

README.md

@@ -4,6 +4,11 @@ This repo contains a list of rotor geometries and the associated experimental
 data. All these data were found in articles, technical reports, theses, etc. The
 reference is always listed alongside the files.
 
+## WARNING
+The data from Caradonna is taken as it is presented in the tables. Upon closer
+inspection, it seems that there is some errors for the sectional lift
+coefficient.
+
 ## Organization
 
 Every entry comes with at least two csv files:
@@ -53,6 +58,7 @@ units, so use it with caution.
 Small scripts/functions will be provided in the future in the `scripts/`
 directory to help you load and parse the data in the most common languages.
 
+
 ## Contributing
 
 Any contribution to this database is more than welcomed. A small python script