vilas
The minimum drag position is some slip neutralised by some bank
.... Yes as John pointed out there is no bank without aileron
I think we are all saying something similar, but using the wrong words.
Slip is usually displayed using a heavy ball (pea) in a "U" tube (which works well for symmetrical thrust flight.) However aerodynamic slip is better measured using streaming lengths of wool across the canopy.
During steady asymmetric flight with rudder balancing yaw and bank towards the live engines to counteract the rudder generated side slip (according to the wool), then the pea would show "slip". In Airbus, the Beta target replaces the streaming wool.
If we have no aerodynamic side slip (streaming wool / Beta) why would we need any aileron?