{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T06:53:49Z","timestamp":1780642429553,"version":"3.54.1"},"reference-count":25,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2023,7,14]],"date-time":"2023-07-14T00:00:00Z","timestamp":1689292800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Major Program for Science and Technology Development of Jilin, China: Key Technologies for the Industrialization of Highly Reliable Fixed-wing UAVs","award":["20170201006GX"],"award-info":[{"award-number":["20170201006GX"]}]},{"name":"Major Program for Science and Technology Development of Jilin, China: Key Technologies for the Industrialization of Highly Reliable Fixed-wing UAVs","award":["20180201106GX"],"award-info":[{"award-number":["20180201106GX"]}]},{"name":"Key Science and Technology Research and Development Projects of Jilin, China: Research on the Key Technologies of UAV Light and Small Swing Scanning Intelligent Aerial Survey System","award":["20170201006GX"],"award-info":[{"award-number":["20170201006GX"]}]},{"name":"Key Science and Technology Research and Development Projects of Jilin, China: Research on the Key Technologies of UAV Light and Small Swing Scanning Intelligent Aerial Survey System","award":["20180201106GX"],"award-info":[{"award-number":["20180201106GX"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents experimental investigations on aerodynamic performance of a ducted coaxial-rotor system to evaluate its potential application as a small unmanned aerial vehicle (SUAV). Aimed at determining the influence of design parameters (rotor spacing, tip clearance and rotor position within the duct) on hover performance, a variety of systematic measurements for several correlative configurations (single\/coaxial rotor with or without a duct) in terms of thrust and torque, as well as power, were conducted in an attempt to identify a better aerodynamic configuration. The experimental results for the coaxial-rotor system indicated that varying rotor spacing affected the thrust-sharing proportion between the two rotors, but this had no significant effect on the propulsive efficiency. The optimal H\/R ratio was identified as being 0.40, due to a larger thrust and stronger stability in the case of identical rotation speeds. As for the ducted single-rotor configuration, the tip clearance played a dominant role in improving its thrust performance, especially for smaller gaps (\u03b4\u22640.015R), while the rotor position made subordinate contributions. The maximum performance was obtained with the rotor located at the P5 position (0.31Cd from the duct lip), which resulted in an enhancement of approximately 20% in power loading over the isolated single rotor. When the coaxial rotors were surrounded within the duct, the system thrust for a given power degraded with the increasing rotor spacing, which was mainly attributed to the upper rotor suffering from heavier leakage losses. And hence, the ducted coaxial-rotor system with S1 spacing had the best propulsion efficiency and hover performance with a figure of merit of 0.61.<\/jats:p>","DOI":"10.3390\/s23146413","type":"journal-article","created":{"date-parts":[[2023,7,14]],"date-time":"2023-07-14T09:03:53Z","timestamp":1689325433000},"page":"6413","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Experimental Investigation on Hover Performance of a Ducted Coaxial-Rotor UAV"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-9263-4848","authenticated-orcid":false,"given":"Hai","family":"Li","sequence":"first","affiliation":[{"name":"Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zaibin","family":"Chen","sequence":"additional","affiliation":[{"name":"Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongguang","family":"Jia","sequence":"additional","affiliation":[{"name":"Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China"},{"name":"Chang Guang Satellite Technology Co., Ltd., Changchun 130102, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Bell, J., Brazinskas, M., and Prior, S.D. (2011, January 9\u201314). Optimizing Performance Variables for Small Unmanned Aerial Vehicle Co-Axial Rotor Systems. Proceedings of the 9th International Conference on Engineering Psychology and Cognitive Ergonomics, EPCE 2011, Orlando, FL, USA.","DOI":"10.1007\/978-3-642-21741-8_52"},{"key":"ref_2","first-page":"12008-1","article-title":"Design, Development, and Testing of a Shrouded Single-Rotor Micro Air Vehicle with Antitorque Vanes","volume":"56","author":"Hrishikeshavan","year":"2015","journal-title":"J. Am. Helicopter Soc."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"779","DOI":"10.2514\/1.C032463","article-title":"Design and Performance of a Quad-Shrouded Rotor Micro Air Vehicle","volume":"51","author":"Hrishikeshavan","year":"2014","journal-title":"J. Aircraft."},{"key":"ref_4","unstructured":"Lee, T.E. (2010). Design and Performance of a Ducted Coaxial Rotor in Hover and Forward flight. [Ph.D. Dissertation, UMD]."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"4045778","DOI":"10.1155\/2022\/4045778","article-title":"A Study on Hover Performance of Ducted Fans for an Unmanned VTOL Aircraft","volume":"2022","author":"Choi","year":"2022","journal-title":"Int. J. Aerosp. Eng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1177\/1687814018823327","article-title":"Aerodynamic performance and analysis of a hovering micro-scale shrouded rotor in confined environment","volume":"11","author":"Han","year":"2019","journal-title":"Adv. Mech. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"12","DOI":"10.4028\/www.scientific.net\/AMM.711.12","article-title":"Experimental Investigation on Aerodynamic Characteristics of Propeller in a Ducted-Fan Type VTOL UAV","volume":"711","author":"Han","year":"2014","journal-title":"Appl. Mech. Mater."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1016\/j.expthermflusci.2012.09.022","article-title":"An experimental investigation on aerodynamic performance of a coaxial rotor system with different rotor spacing and wind speed","volume":"44","author":"Lei","year":"2013","journal-title":"Exp. Therm. Fluid Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1465","DOI":"10.2514\/1.C031971","article-title":"Experimental Performance Evaluation of Coaxial Rotors for a Micro Aerial Vehicle","volume":"50","author":"Singh","year":"2013","journal-title":"J. Aircraft."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"216","DOI":"10.4028\/www.scientific.net\/AMM.427-429.216","article-title":"Research on Hover Characteristics of Ducted Fan with Coaxial Rotors","volume":"427\u2013429","author":"He","year":"2013","journal-title":"Appl. Mech. Mater."},{"key":"ref_11","first-page":"87","article-title":"Design and testing of coaxial rotor ducted fan VTOL UAV","volume":"24","author":"Kartidjo","year":"2017","journal-title":"Jurnal Teknik Mesin."},{"key":"ref_12","first-page":"18","article-title":"Hover Tests of Micro Aerial Vehicle-scale Shrouded Rotors, Part I: Performance Characteristics","volume":"54","author":"Pereira","year":"2009","journal-title":"J. Am. Helicopter Soc."},{"key":"ref_13","first-page":"12002-1","article-title":"Hover Tests of Micro Aerial Vehicle-Scale Shrouded Rotors, Part II: Flow Field Measurements","volume":"54","author":"Pereira","year":"2009","journal-title":"J. Am. Helicopter Soc."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"362","DOI":"10.1177\/1756829318804763","article-title":"Optimization of aerodynamic performance for co-axial rotors with different rotor spacings","volume":"10","author":"Lei","year":"2018","journal-title":"Int. J. Micro Air Veh."},{"key":"ref_15","first-page":"1","article-title":"Aerodynamics Optimization of a Ducted Coaxial Rotor in Forward Flight Using Orthogonal Test Design","volume":"5","author":"Jia","year":"2018","journal-title":"Shock Vib."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"105895","DOI":"10.1016\/j.ast.2020.105895","article-title":"Aerodynamic performance assessment of a ducted fan UAV for VTOL applications","volume":"103","author":"Deng","year":"2020","journal-title":"Aerosp. Sci. Technol."},{"key":"ref_17","first-page":"1","article-title":"Efficient computational fluid dynamics approach for coaxial rotor simulations in hover","volume":"58","author":"Cornelius","year":"2020","journal-title":"J. Aircraft"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Konstantinov, S.G., Ignatkin, Y.M., Makeev, P.V., and Nikitin, S.O. (2021). Comparative study of coaxial main rotor aerodynamics in the hover with the usage of two methods of computational fluid dynamics. J. Aerosp. Technol. Manag., 13.","DOI":"10.1590\/jatm.v13.1210"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"529","DOI":"10.2514\/1.C036664","article-title":"Analytical and Computational Study of Hover Performance of Novel Dissimilar Coaxial Rotor","volume":"59","author":"Ramanujam","year":"2022","journal-title":"J. Aircraft."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3","DOI":"10.4050\/JAHS.17.4.3","article-title":"The Wake Geometry of a Hovering Helicopter Rotor and Its Influence on Rotor Performance","volume":"17","author":"Landgrebe","year":"1972","journal-title":"J. Am. Helicopter Soc."},{"key":"ref_21","first-page":"12004\u20131","article-title":"A Comparison of Coaxial and Conventional Rotor Performance","volume":"55","author":"Kim","year":"2010","journal-title":"J. Am. Helicopter Soc."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/we.2330","article-title":"Numerical\/experimental investigations on reducing drag penalty of passive vortex generators on a NACA 4415 airfoil","volume":"22","author":"Fouatih","year":"2019","journal-title":"Wind Energy"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"290","DOI":"10.4050\/JAHS.53.290","article-title":"Figure of Merit Definition for Coaxial Rotors","volume":"53","author":"Leishman","year":"2008","journal-title":"J. Am. Helicopter Soc."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2140","DOI":"10.37188\/OPE.20212909.2140","article-title":"Experimental Investigation on Aerodynamic Characteristics of a Coaxial Rotor System","volume":"029","author":"Li","year":"2021","journal-title":"Opt. Precis. Eng."},{"key":"ref_25","unstructured":"Coleman, C.P. (2023, May 09). A Survey of Theoretical and Experimental Coaxial Rotor Aerodynamic Research, Available online: https:\/\/ntrs.nasa.gov\/api\/citations\/19970015550\/downloads\/19970015550.pdf."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/14\/6413\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T20:12:18Z","timestamp":1760127138000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/14\/6413"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,7,14]]},"references-count":25,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2023,7]]}},"alternative-id":["s23146413"],"URL":"https:\/\/doi.org\/10.3390\/s23146413","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,7,14]]}}}