You are right Globe. I did some investigation yesterday evening. A 120mm fan is sufficient with a good electricengine that can rev high. Not counting in the batteriepacks needed to run the engine and the rest, the power generated will get 9kg in the air without a problem.
The plane is at the moment an empty shell, Maybe i need the 140mm fan.
Length: 148.5cm
Wingspan: 107cm
Height: 53cm
Weight: 2kg (just weighed it)