Some Digits ???
I have some :D
Motor was the 820 from Graupner.
Cells & speed (GPS measured) :
16 RC1700, prop was too low, 41 Km/h
18 GP3300 P&M, prop higher, 47 Km/h
21 RC1700, 52 Km/h. The best run of the day. The hull began to really move.
Prop was k43.5, I'll try the one provided...