Review Reports

Round 1

Reviewer 1 Report

Authors proposed criteria of the Vertiports are based on the FAA heliports standards and recomended practices. 

The proposed criteria, in particular the characteristics of the obstacle limitation surfaces are not justified. Why is the approach / departure surface starting at the end of FATO and not at the end of the safety area? The upwards slope 8:1 (the author probably means 1:8) could be sufficient for some types of crafts, however, for different characteristics and performance a more stringent criteria should be applied. The divergence of the approach / departure surface seems to be insufficient. The transition surface is not designed, why?

Although the vertiport is designed for Korea's conditions, it is strongly recommended to compare the proposed criteria with the first standard for vertiports: “EASA Vertiports Prototype Technical Specifications for the Design of VFR Vertiports for Operation with Manned VTOL-Capable Aircraft Certified in the Enhanced Category” 

The authors should also discuss the open concept topology of vertiports.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Too fewer literature was referred to for the academic Research article. (As mentioned in the paper, the current paper was subsidised by a project). The outputs of their project can be valuable, But they needed to imply what is the differences between the current literature. 

The fact that the literature used in the first chapter (although the access date is new) has an old reference weakened the innovative side of the study.

There are no outputs, neither comparing the literature and aviation studies nor presenting the innovative side. This is a weakness.

Parametric results in the Abstract and Conclusion sections are not included.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

This is an interesting paper and addresses some concerns with regard to the currently underdevelopment standards for the design of vertiports. Particularly, the authors are addressing the required site space and design criteria for a vertiport to efficiently utilize the limited available urban space in a UAM operation. From my point of view, the paper needs major revision to be ready for publication in one of the MDPI journals. The main concern is that the authors need to upgrade their work in accordance with the recently released regulations for Vertiport Design by FAA (Engineering Brief No. 105, Vertiport Design). Some of the assumptions made in the paper are not consistent with those values provided by FAA for the Vertiport design. Secondly, the journal of Applied Science may not be a good match for this paper. I would recommend transferring this paper to the Aerospace section as the content of the paper is more relevant to the MDPI Aerospace journal. Also, I have some comments and suggestions provided as follows.

 

Comments and Suggestions:

• Shouldn’t it be diagonal length instead of fuselage in page 2, bottom of the page?

Page 2: “In this study, to provide a sufficient margin, the size of the vertiport components was determined based on the size of the Hyundai S-A1 fuselage, which is classified as a large eVOTL aircraft.”

• Standards used in this paper are mostly from Helicopter standards which are not applicable now for the vertiport design. The authors need to upgrade their work using the recently released regulations for Vertiport Design by FAA (Engineering Brief No. 105, Vertiport Design). For example, Figure 2 page 4 is offering a safety zone of 2.5 AD while FAA suggest 3AD. Also, it is better to refer use the same terms suggested by FAA in your paper. For example, FAA uses controlling dimension; CD instead of AD to define the safety zone and other terms.
  • Draft EB 105, Vertiport Design, June XX, 2022 (faa.gov)
• Page 11: You need to define what you mean from each step (step 5 in Paragraph 2). Maybe you can add some text on each step in Figure 14 beside the labels of the steps.
• Figure 15; Page 12: captions should explain different sections defined there as well

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Page 3: To prevent a short circuit or lighting strike, a concrete surface is recommended on elevated TLOFs.

Comment: In the case of elevated heliports with reinforced concrete construction of TLOF/FATO, cases of autopilot and avionics failure have been reported in some types of helicopters due to the creation of a strong magnetic field in the reinforced concrete slab. This could be an issue for UAM with advanced avionics.

 

Page 5:  “....passengers are not allowed to board and unboard at the runway …“; “…the passengers are boarding and unboarding …”

Usually expressions deplane;  disembark  are used

 

Page 7: “…slopes upward at 8:1  for a distance …”

Correct: 1:8

 

Page 10: Figure 9 and Figure 10

Correct in the picture 8:1 and 2:1; correctly to 1:8  and 1:2

 

Page 11: This layout separates the area of ​​the TLOF

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The authors have made the revision according to the reviewer's report.

Author Response

The revised parts of this manuscript was proofread by a professional Language Institute. And the revisions were marked in the applsci-1647115_R2.docx.