Thank you!, I played a bit with the values, It seems the CdFlap value is extraordinarily high, by default is set to 0,4 on the 172. The wiki recommends 0,06 for slotted flaps, such as the C172 (there seems to be some discussion on what kind of flaps does the Cessna have, however the manual refers it as "single-slot type wing flaps")
Had a quick flight with 0,1 and the difference was substantial, the plane behaved much more realistically on approach, I'll play around with other values.
Is there a reason to use such a large value?
Table of flap coefficients
Recommended values for the Aerofly are:
|Type of flap||ClFlap||CdFlap||CmFlap|
|Plain flap||2.1||0.0||-0.2 … -0.5|
|Split flap||2.4||0.2||-0.2 … -0.9|
|Fowler flap||2.7 … 3.4||0.2||-0.6 … -1.1|