def export_eng(self, file_name, motor_name):
        """Exports thrust curve data points and motor description to
        .eng file format. A description of the format can be found
        here: http://www.thrustcurve.org/raspformat.shtml

        Parameters
        ----------
        file_name : string
            Name of the .eng file to be exported. E.g. 'test.eng'
        motor_name : string
            Name given to motor. Will appear in the description of the
            .eng file. E.g. 'Mandioca'

        Returns
        -------
        None
        """
        # Open file
        with open(file_name, "w") as file:
            # Write first line
            def get_attr_value(obj, attr_name, multiplier=1):
                return multiplier * getattr(obj, attr_name, 0)

            grain_outer_radius = get_attr_value(self, "grain_outer_radius", 2000)
            grain_number = get_attr_value(self, "grain_number", 1000)
            grain_initial_height = get_attr_value(self, "grain_initial_height")
            grain_separation = get_attr_value(self, "grain_separation")

            grain_total = grain_number * (grain_initial_height + grain_separation)

            if grain_outer_radius == 0 or grain_total == 0:
                warnings.warn(
                    "The motor object doesn't have some grain-related attributes. "
                    "Using zeros to write to file."
                )

            file.write(
                f"{motor_name} {grain_outer_radius:3.1f} {grain_total:3.1f} 0 "
                f"{self.propellant_initial_mass:2.3} "
                f"{self.propellant_initial_mass:2.3} RocketPy\n"
            )

            # Write thrust curve data points
            for time, thrust in self.thrust.source[1:-1, :]:
                file.write(f"{time:.4f} {thrust:.3f}\n")

            # Write last line
            file.write(f"{self.thrust.source[-1, 0]:.4f} {0:.3f}\n")

        return None