The authors introduced a new correction to account for dynamic effects in turbine blades with complex out-of-plane shapes (pre-coned, dihedral). The latter consists in the use of two reference points for the computation of aerodynamic forces from input 2D polar data. Quarter-chord position is used to assess the aerodynamic force direction, the three-quarter chord one for the evaluation of its magnitude. This new formulation has been implemented in different low-order models (LLT, BEM, BEVC and ALM) and validated against blade-resolved CFD simulations of a large-scale rotor, showing promising results. The reviewer believes that the topic and the activity are very interesting, innovative and worthy of investigation. The study is extensive and the investigation approach is adequate and consistent throughout the whole activity. Notwithstanding this, the paper is not very well presented and some conceptual passages are not clear. Some specific considerations:

• Abstract: it is not clear why the BEM belongs to the Lifting Line (LL) class of methods (line 3)
• Abstract: the passage at lines 5-8 is not very clear
• Section 1 (Introduction): the relationship between low-order models, dynamic stall models and the proposed correction is not very clear. The author should also discuss better what is the advantage of the proposed solution with respect to a modern dynamic stall model such as the Beddoes-Leishman one, which, according to what stated by the authors in the conclusions, is able to yield the same results
• Section 3: the demonstration of the proposed solution from the unsteady thin airfoil theory is quite hard to follow. In the Reviewer’s opinion, it would be better to divide the demonstration according to the specific features of the correction, i.e., what point to use for direction and magnitude of the computed aerodynamic force
• Organization of the content in sections 3 and 4 is quite chaotic, with a lot of redundant information. The Reviewer suggests re-arranging the content in a more concise way, using a table as a support to resume all the different modelling combinations used in the investigation
• The use of the first-person plural (e.g., in line 46) is not recommended for a scientific publication and should be replaced with something more impersonal

Based on the aforementioned comments, the reviewer recommends the publication of this paper after the suggested revisions have been performed.

The paper assesses the importance of the collocation point selection on the calculated sectional and overall blade and rotor aerodynamic loads of no-planar rotors, in the context of BEM, lifting line and actuator line methods (all of which based on a 1D representation of the blades).

In order to assess the validity of their assumptions, the authors compare the results of the different implementations for the sectional loads calculation against fully resolved CFD results. The results clearly indicate that the collocation point selection is not of major importance for the calculation of the magnitude of the effective flow velocity but it plays a very important role in the consistent calculation of the CL (consistent definition of the aoa) and the flow direction with respect to which lift and drag forces are analyzed into thrust and tangential force.

The findings of the work are well supported by computations with all the 1D aerodynamic variants, which are compared to fully resolved CFD results.

The paper is well structured and written and it presents important results which are valuable to the research community. Therefore I recommend publication of the paper is WES, after some revision is made to the original text.

• Several comments-corrections (including grammar/syntax) can be found in the accompanying pdf file
• In the beginning of section 2, the statement that the flow in the wake of the rotor is irrotational is incorrect. Please see the comment in the pdf.
• A change which would definitely contribute to improving clarity, is a figure (and the accompanying discussion) that illustrates the correspondence between 2D Theodorsen theory parameters against the 3D blade sectional parameters. For example, in the text, in eq 1 a Dar angle is defined which is supposed to include the effect of the section motion on the angle of attack. However this clearly should not include pitching angle of the section which however alters the angle of attack. Furthermore, in the same expression, it is not perfectly clear what θ angle stands for. The same θ notation is used in eq 3 where it represents the pitching motion of the section. However, this pitching motion does not alter the inflow angle which should be the one used in eq 1. Then how all the above angles are transferred in the section of the blade. Furthermore, what is the direction along which heaving motion is defined? In Theodersen theory this is supposed to be perpendicular to the local inflow velocity. This direction seems to be defined differently in the paper (most probably normal to the chord).