How to smoothly rotate an object to certain values? in 2d?

Question

Unity

Need smooth z rotation in a 2d game with +-15 degree borders.

public float minimumUp;
public float maximumDown;

private float aircraftRotaion = 0;
void update()
    {
     aircraftRotaion =Mathf.Clamp(aircraft,minimumUp,maximumDown);
    }

Answer 1

I'm certainly not a professional, but I use multiplications by Time.deltaTime