And if an ATR 72 is on a short runway, can it use flaps 2 instead of the normal 1 for take off?
If you are runway limited, then you increase flaps setting to increase lift and lower
the V-speeds. This is mandatory on short runways
except situations when
you have obstacles or when airports pressure altitude is a bit high.
And a last question: on Airbus it is called config 1 etc (I´m not really sure) what is is called on ATR?
It's not really important what they call it, most important is to know how they
affect the airplanes performance. On the bus there are:
CONFIG 1+F (F1)
CONFIG 2 (F2)
CONFIG 3 (F3 highest for TKF and AC OFF)