(Aeronáutica) Artículos

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Enhancing Operational Efficiency of the Raman Laser Spectrometer (RLS) in the ExoMars Rosalind Franklin Mission: A Comprehensive Qualitative Analysis of Key Parameters in the Sample Acquisition and Measurement Strategies
(Wiley, 2025-06-15) Pérez, Carlos; Moral, Andoni G.; Seoane, Laura; Zafra, Jesús; Rodriguez Perez, Pablo; Benito Parejo, Marina; Rodríguez, J. A.; Canchal, R.; Santamaría, Pilar; López, Iván; Molina, A.; Manrique, J. A.; Veneranda, M.; López Reyes, Guillermo; Prieto-Ballesteros, Olga; Rull, F.; Agencia Estatal de Investigación (España)
The Raman Laser Spectrometer (RLS), part of the Pasteur analytical suite onboard the ExoMars 2028 Rosalind Franklin rover, is designed to perform structural and compositional analyses of powdered subsurface samples on Mars. Its fully autonomous operation within the constraints of the Pasteur Analytical Laboratory-limited by time, energy, and sample availability-requires an efficient balance between scientific performance and operational viability. This study presents a qualitative analysis of RLS operations under mission-representative conditions using the Flight Spare (FS) model, focusing on the impact of key parameters-number of accumulations, autofocus frequency, and analyzed spots per sample-on the system's detection capabilities. Experimental campaigns were conducted using ESA-selected analog samples representative of Oxia Planum geology. Performance was evaluated using both the RLS FS and the ExoMars Simulator. Results show high consistency (90-95%) in mineral detection between systems, confirming the robustness of the RLS FS under representative scenarios. The instrument demonstrated its ability to identify key phases, including oxides, silicates, carbonates, hydrated sulfates, and amorphous carbon, highlighting its relevance to geological and astrobiological investigations. Operational tests confirmed that reducing the number of accumulations or autofocus activations-under appropriate sample conditions-does not compromise spectral quality. These findings support a flexible strategy that adapts operational parameters to the scientific context, optimizing resource use and preserving long-term instrument reliability. The results will contribute to the refinement of nominal activity plans for ExoMars and reinforce the use of the RLS FS as a critical asset for validating future configurations of the flight model.
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Long term diffusion studies in Fe aluminide coatings deposited by slurry application on ferritic steel
(Scientific.Net, 2009-04-22) Agüero, Alina; González, Vanessa; Gutiérrez del Olmo, Marcos
Diffusion iron aluminide coatings have shown excellent resistance to high temperature oxidation in air, corrosive atmospheres and steam. A study of the diffusion behaviour of slurry applied diffusion aluminide coatings deposited on ferritic steel have been carried out under a 100% flowing steam atmosphere for up to 50,000 h at 650 °C. The results have shown that initially, the coating forms by outward growth possibly including the dissolution of the steel in molten aluminium. At later stages, during exposure to steam at 650 °C, aluminium diffuses inward and moreover, Fe also diffuses outward resulting in the progressive development of Kirkendall porosity. Results have also indicated that in order to form a pure protective Al2O3 scale the Al wt.% has to be > 4. Below this content Al-Fe mixed oxides develop exhibiting a less protective behaviour.
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Comparison between field and laboratory steam oxidation testing on aluminide coatings on P92
(Wiley online library, 2011-01-12) Agüero, Alina; González, V; Gutiérrez del Olmo, Marcos; Knödler, R; Straub, S; Muelas Gamo, Raúl; Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Steam oxidation has become an important issue for steam power plants as operating temperatures increase from the current 550 to 600–650 °C. For the last 10 years several groups have been carrying out steam oxidation testing of both uncoated substrates and coatings in the laboratory. On the other hand, field testing results are very scarce. In this paper, a comparison of laboratory steam oxidation testing with field test results carried out by Alstom at the Kraftwerk Westfalen power station located in Hamm, Germany will be presented. Both slurry deposited aluminide coatings and uncoated P92 steel have been included in the study. Under steam (atmospheric pressure) and isothermal conditions in the laboratory at 650 °C, spallation of oxides formed on ferritic steels occurs after significantly longer time when compared to exposure to real operating conditions. Oxide spallation results in serious damage in steam power plants by obstructing heat exchanger tubes, erosion of valves and turbine blades, etc. Moreover, the thickness of the oxide scales formed under field testing conditions is significantly higher after similar exposure. On the other hand, aluminide coated P92, which exhibit thickness through cracks, have shown to be stable in the laboratory for up to 60 000 h at 650 °C under steam, without evidence of crack propagation. However, field test results indicate that some degree of crack propagation occurs but without causing substrate attack up to 21 700 h of exposure. Moreover, the aluminium oxide observed in both laboratory and field tested specimens is different.
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Metal Dusting Protective Coatings. A Literature Review
(Springer Nature Link, 2011-03-20) Agüero, Alina; Gutiérrez del Olmo, Marcos; Korcakova, L; Nguyen, T. T. M; Hinnemann, B; Saadi, S
Metal dusting is a catastrophic form of carburization attack that takes place in carbon-supersaturated gaseous atmospheres, and is most commonly encountered in steam reforming processes such as the production of hydrogen or syngas for ammonia, Fischer–Tropsch and methanol applications. The consequence of metal dusting can be a severe loss of metal from the process units, leading to high-cost maintenance and serious safety issues. The present literature review discusses the latest developments within metal dusting protection of alloys with special emphasis on protective coatings. In the first part of the paper, an overview of the main theories for metal dusting of alloys as well as fundamental studies is provided. In the second part, the paper focuses on the different methods to prevent metal dusting, including surface poisoning, alloying, chemical, mechanical and laser treatments as well as coatings. Particular focus is given to coatings and their composition, and fabrication methods, and a critical analysis of the different materials’ behaviours and the suitability perspectives of deposition techniques are provided.
Acceso Abierto
Development and Qualification of New Solid Lubricant Coatings. A Tribology Experiment at the Tribolab onto EUTEF
(Centre national d'études spatiales (CNES), 2000-06-12) Oñate, J. Ignacio; Brizuela, Marta; García Luis, Alberto; Viviente, J. Luis; García de Blas, Javier; Agüero, Alina; Longo, Federico; Román, Alicia
A recent study has identified that a significant number of satellite failures and anomalies, including those caused during qualification testing of mechanisms, were caused by lubrication related problems. Solid lubrication is, owing to lower vapour pressures, better boundary lubrication properties, relative insensitivity to radiation effects and wider temperature range of operation, still a preferred option for a number of space mechanisms. However, actual solid lubricants wear out and do not provide effective protection for long life mechanisms. A longer life and reduced wear debris is desirable to improve mechanism reliability. The present work reports on early results on the development of a new generation of solid lubricant coatings by the use of state of the art magnetron sputtering technology and thermal spraying processes. These coatings after a proper qualification procedure under laboratory ground conditions will be finally tested at the TriboLAB instrument that will be integrated onto the EuTEF facility at the International Space Station (ISS). Metal alloyed MoS2 solid lubricant films have been produced by a magnetron sputtering PVD process. Tribotests carried out under vacuum in a ball-on-disc tribometer with MoS2 coated AISI 440C steel discs have shown very low friction coefficients of 0.01 and long endurance, in excess of 300,000 revolutions at about a max. 0.8 GPa contact stress. These films also exhibited low friction coefficients (about 0.10) and good durability under atmospheric conditions at RT and up to 50 to 60 % RH. The thick composite lubricant coatings consisting of AlCoFeCr, NiCr, Ag and BaF2-CaF2 were deposited by plasma spray and HVOF on X-750 Ni-base superalloy. These coatings have been characterised by EDS-SEM as well as hardness measurements. The best coatings from preliminary experiments have been produced by HVOF process; these show very low porosity, a more uniform phase distribution and hardness levels of 635 HV0.2. Anticipated high temperature applications of former coatings might include elevon hinges for re-usable space planes.
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Microstructures of thin and thick slurry aluminide coatings on Inconel 690
(Elsevier, 2007-07-05) Juul Rasmussen, Anders; Agüero, Alina; Gutiérrez del Olmo, Marcos; Landeira Østergård, María José
Two slurry aluminide coatings are produced on the Ni-base super alloy Inconel 690 by applying two different thicknesses of the same slurry on to the 690 substrate, followed by a two-step heat-treatment. The resulting thin aluminide coating consists of a single layer of Ni-rich β-NiAl matrix containing few large Cr precipitates with a high P content. The thick aluminide coating has a precipitate free inner layer of Ni-rich β-NiAl. An outer layer of Al-rich β-NiAl with many α-Cr precipitates has formed as well. The present metallurgical characterization shows a significant influence of slurry thickness on the morphology and composition of the coatings formed during heat treatment.
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Progress in the development of coatings for protection of new generation steam plant components
(Taylor and Francis online, 2008-11-15) Agüero, Alina
Coatings to prevent component oxidation in future supercritical high temperature steam turbines were developed for the first time in Europe during the COST522 programme. Promising results were obtained with slurry applied aluminide coatings and with a series of thermal sprayed coatings (FeAl, FeCrAl, NiCr and AlFeCoCr) deposited on P92. Since then, extensive research internationally has examined coatings to protect against steam oxidation, deposited by techniques including pack cementation, electroplating and chemical vapour deposition (fluidised bed and organometallic as well as thermal). The results of these studies, including steam oxidation and mechanical data are summarised, and the performance of the candidate systems is critically reviewed from the viewpoint of both materials behaviour and deposition technologies. An earlier version of this paper has been published in the proceedings of the "8th Advanced Power Generation" conference held in Liege, Belgium in September 2006. This version has been updated with the latest available results.
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HVOF coatings for steam oxidation protection
(Wiley online library, 2008-05-29) Agüero, Alina; Muelas Gamo, Raúl; González, Vanessa; Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
In the context of the European project ‘Coatings for Supercritical Steam Cycles’ (SUPERCOAT), the use of steam oxidation resistant coatings on currently available ferritic materials with high creep strength but poor oxidation resistance was investigated in order to allow increase in the operating temperature of steam power plants from 550 to 650 °C. Among the explored coating techniques for this application, chosen on the basis of being potentially appropriate for coating steam turbine components, High Velocity Oxy Fuel (HVOF) thermal spray has resulted in one of the most successful techniques. Different alloyed materials such as FeCrAl, NiCrSiFeB, FeAl, NiCr and FeCr have been deposited, optimized and tested under flowing steam at 650 °C. Characterization of as deposited and tested samples by metallography, SEM-EDS and XRD was carried out. Some of these coatings form protective pure chromium or aluminium oxides exhibiting excellent behaviour for at least 15 000 h of exposure, whereas others form less stable complex mixed oxides which nevertheless grow at considerably slower rates than the oxides formed on uncoated P92 (9 wt% Cr ferritic steel).
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Deposition process of slurry iron aluminide coatings
(Taylor and Francis online, 2008-10-04) Agüero, Alina; Gutiérrez del Olmo, Marcos; González, Vanessa
Diffusion iron aluminide coatings prevent steam oxidation of ferritic/austenitic steels at 650°C for at least 45,000 h. These coatings are deposited by applying Al slurries followed by a diffusion heat treatment at 650°C. The quality of the coatings is very sensitive to a number of factors such as surface preparation, slurry composition and diffusion treatment temperature. A study of the effect of the different processing parameters has been performed in order to optimize the process from an industrial perspective. Moreover, most commercially available Al slurries contain different levels of Cr6+, a highly carcinogenic species, and therefore Cr6+ free slurry formulations have been prepared. In addition, re-coating after exposure has also been developed since it is not clear yet if these coatings will last the 100,000 h which is the life limit for steam power plant design. Based on these studies, processes suitable for coating real size components and re-coating steam exposed components have been developed and are presented in this contribution.
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Microstructural Evolution of Slurry Fe Aluminide Coatings during High Temperature Steam Oxidation
(Trans Tech Publications, 2008-09-15) Agüero, Alina; Spiradek, Krystina; Höfinger, S; Gutiérrez del Olmo, Marcos; Muelas Gamo, Raúl
Slurry iron aluminide coatings are very resistant to steam oxidation at 600-650º C. These coatings can be used to protect new generation Ultra Super Critical (USC) steam power plant ferritic/martensitic steel components. The microstructure of the initially deposited coating changes as a function of time, mainly due to coating-substrate interdiffusion, going from mostly Fe2Al5 to FeAl, causing the precipitation of AlN in those substrates containing a minimum content of N and moreover, developing Kirkendall porosity at the coating-substrate interface. Steam oxidation at 650º C causes the formation of a protective thin layer of hexagonal χ-Al2O3 phase along with some α- and γ-Al2O3 after the first few hours of exposure. However, despite the relatively low temperature, and after several thousands hours the protective layer was mostly composed of α-Al2O3. A study of the evolution of the microstructure of slurry aluminide coatings deposited on P92 and exposed to steam at 650º C has been carried out by scanning and transmission electron microscopy and X ray diffraction.
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Wall boundary conditions for lattice Boltzmann simulations of turbulent flows with wall functions
(AIP Publishing, 2025-09-02) Ponsin Roca, Jorge; Lozano, Carlos
This paper investigates wall boundary condition schemes for the simulation of turbulent flows using the lattice Boltzmann method (LBM) coupled to turbulence models with wall functions. The analysis focuses on two schemes: a regularized boundary scheme with third-order reconstruction of the velocity gradients using wall function data and a slip-velocity bounce-back scheme. The LBM solver is coupled to the Spalart–Allmaras turbulence model and uses a model consistent wall function. The performance of the wall boundary schemes is assessed in two canonical turbulent flow cases, a fully developed channel flow and a zero-pressure-gradient flat plate boundary layer, selected specifically to isolate and analyze the impact of wall boundary treatments on turbulence modeling. The analysis shows that, for the selected test cases, the slip-velocity bounce-back approach, which has received relatively little attention within the context of LBM coupled to Reynolds-averaged Navier–Stokes turbulence models with wall functions, behaves fairly consistently in terms of both accuracy and mesh convergence. The regularized-based approach, on the other hand, appears to be highly sensitive to the reconstruction of the wall-normal velocity gradient, even in simple geometries, such as flat walls, where no interpolation is required. This dependency of the regularized boundary schemes on near-wall gradients, which had been noted before in the literature, requires the use of ad hoc gradient reconstruction techniques, requirements that are not present in the slip-velocity bounce-back method. A hybrid regularized boundary scheme that blends two different gradient reconstruction techniques but requires calibration is introduced as a tool to investigate this effect.
Acceso Abierto
Calibration of a 3-Component External Balance for MAVs Wind Tunnel Research
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-12-02) Bardera, Rafael; Rodríguez Sevillano, A.; Barroso, Estela; Sor, Suthyvann; Matías García, J. C.; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)
This paper presents a 3-component external balance, specifically designed, built, and calibrated at the National Institute for Aerospace Technology (INTA) for measuring aerodynamic forces on Micro Aerial Vehicles in the wind tunnel. The balance employs high-precision strain gauge cells as its load-sensing elements, strategically positioned in a metallic structure to measure lift force, aerodynamic drag force, and pitching moment. The entire calibration process of the balance, including the mathematical formulation to derive the calibration matrix and the calibration bench designed and manufactured for this purpose, is detailed in this paper. Moreover, the complete analysis of component interferences of the aerodynamic components and an assessment of the uncertainties inherent in the system are presented.
Acceso Abierto
Numerical Analysis of Bioinspired Tails in a Fixed-Wing Micro Air Vehicle
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-09-08) Bardera, Rafael; Barroso, Estela; Rodríguez Sevillano, A.; Matías García, J. C.
"Bird tails play a key role in aerodynamics and flight stability. They produce extra lift for takeoff and landing maneuvers, enhance wing functions and maintain stability during flight (keeping the bird from yawing, rolling and pitching, or otherwise losing control). This paper investigates the use of bioinspired horizontal stabilizers for Micro Air Vehicles (MAVs) involving a Zimmerman wing-body geometry. A selection of five tail shapes of the main types existing in nature is presented, and a parametric analysis is conducted looking into the influence of the most relevant tail geometric parameters to increase the longitudinal static stability of the vehicle. Based on the parametric study, a smaller subset of candidate tail designs are shortlisted to perform a detailed aerodynamic analysis. Then, steady RANS CFD simulations are conducted for a higher-fidelity study of these candidate tail designs to obtain an optimum of each tail type. The criterion for selection of the optimum tail configuration is the maximum aerodynamic efficiency, CL /CD , as well as a high longitudinal static stability. The squared-fan tail provides the highest aerodynamic efficiency while maintaining a high longitudinal stability of the vehicle. In conclusion, this paper provides an innovative study of improving longitudinal stability and aerodynamics through the implementation of bioinspired horizontal stabilizers in vehicles with these characteristics."
Acceso Abierto
Numerical analysis of the thermal convection through a flat plate in Martian conditions
(Elsevier, 2024-06-11) Bardera, Rafael; Rodríguez Sevillano, A.; Barroso, Estela; Matías García, J. C.; López Cuervo, Alejandra; Instituto Nacional de Técnica Aeroespacial (INTA)
There are currently several investigations being developed around Mars, primarily focused on the aerodynamics of drones and the study of atmosphere flow and Martian soil with the assistance of the Perseverance rover. Several phenomena in the Martian atmosphere can complicate flow measurements, and the Multi Mission Radioisotope Thermoelectric Generator (MMRTG) at the rear of the rover can introduce additional uncertainty to the measurements. These measurements are conducted with the system called MEDA, which is located at the front of the rover, under its head. Therefore, it is considered of interest to carry out a preliminary study to determine the feasibility of performing tests on Earth simulating the Martian atmosphere without the need for a vacuum chamber. This would make it possible to streamline and simplify the methods used. The aim of this work is to perform simulations on a plate, that can be considered as a simplification of the MMRTG heat exchanger system, which is composed of a cylinder with flat fins around it, over free and forced convection to verify whether flow behaviour in Martian conditions can be obtained from dimensional analysis on Earth.
Acceso Abierto
CFD study of the effect of leading-edge tubercles on the aerodynamic characteristics of a small UAV based on eppler 186 airfoils
(Elsevier, 2024-09-12) Bardera, Rafael; Rodríguez Sevillano, A.; Barroso, Estela; Matías García, J. C.; Instituto Nacional de Técnica Aeroespacial (INTA)
A numerical analysis is carried out to evaluate the aerodynamic characteristics of a small Unmanned Aerial Vehicle (UAV) whose wings are modified to incorporate sinusoidal leading edges (tubercles). This UAV has a rectangular wing composed of Eppler 186 airfoils. The aerodynamic characteristics of four UAV configurations varying the wavelength and amplitude along the wingspan are evaluated using Computational Fluid Dynamics (CFD). Results are compared with the baseline case, that is, without leading-edge tubercles. The wing configu rations with tubercles exhibited increased lift at high angles of attack and delayed stall. The configuration with maximum amplitude (a = 0.05c) and minium wavelength (λ = 0.25c) achieved an increase up to 17 % in the maximum lift coefficient and delayed the stall up to the angle of attack of 20◦ compared to the baseline case.
Acceso Abierto
From conventional to bioinspired: Evolution of tail surface designs in micro air vehicles
(Elsevier, 2024-12-23) Rodríguez Sevillano, A.; Bardera, Rafael; Barroso, Estela; Matías García, J. C.; López Cuervo, Alejandra; Instituto Nacional de Técnica Aeroespacial (INTA)
The paper presents the evolution of the tail surface design of a micro air vehicle based on adaptive wing geometry. The initial prototype was conceived as a tailless aircraft geometry, waiting for future innovations and stability augmentations. An initial experimental test bench will be presented to characterize the variation of wing profile curvature as a function of the voltage, through MFC actuators. Once these results have been analyzed, the process of conceiving a conventional T-tail was initiated, ultimately evolving toward the proposal of a bioinspired tail based on the tail shape of various birds. The results obtained in wind tunnel tests using PIV techniques will be presented. The results validate the selected tail surface design as an appropriate geometry for a bioinspired micro air vehicle.
Acceso Abierto
Theoretical model for microbubble drag reduction technique applied to marine propellers
(Elservier, 2025-06-15) García-Magariño, Adelaida; Sor, Suthyvann; Bardera, Rafael; López Gavilan, Pablo; Instituto Nacional de Técnica Aeroespacial (INTA)
An increase in the propeller efficiency could result in a reduction of the contaminant emissions of ships. The reduction of drag by means of injecting microbubbles in the boundary layer of the blade of propeller is first studied in this article based on the fluid mechanics theory and the fundamental knowledge of this recent technique (that is usually applied to the hull of ships instead). A theoretical approach is proposed to evaluate the drag reduction due to the bubbles presence inside the boundary layer. This is a new application of bubbles dynamic to reduce the drag of the blades of the marine propellers, thus increasing their efficiency.
Acceso Abierto
Wind Tunnel Balance Measurements of Bioinspired Tails for a Fixed Wing MAV
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-01-10) Bardera, Rafael; Rodríguez Sevillano, A.; Barroso, Estela; Matías García, J. C.; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)
"Bird tails play a significant role in aerodynamics and stability during flight. This paper investigates the use of bioinspired horizontal stabilizers for Micro Air Vehicles (MAVs) with Zimmerman wing-body geometry. Five configurations of bioinspired horizontal tabilizers are presented. Then, 3-component external balance force measurements of each horizontal stabilizer are performed in the wind tunnel. The Squared-Fan-Shaped Horizontal Stabilizer (HSF-tail) is selected as the optimal horizontal stabilizer that provides the highest aerodynamic efficiency during cruise flight while maintaining high longitudinal stability on the vehicle. The integration of the HSF-tail increases the aerodynamic efficiency by more than 6% up to a maximum of 17% compared to the other alternatives while maintaining the lowest aerodynamic drag value during the cruise phase. Furthermore, balancemeasurements to analyze the influence of the HSF-tail deflection on the aerodynamic coefficients are conducted, resulting in increased lift force and reduced aerodynamic drag with negative tail deflections. Lastly, the experimental data is validated with CFD-RANS steady simulations for low angles of attack, obtaining a relative difference on the measurement around 5% for the aerodynamic drag coefficient and around 10% for the lift coefficient during the cruise flight that demonstrates a high degree of accuracy in the aerodynamic coefficients obtained by external balance in the wind tunnel. This work represents a novel approach through the implementation of a horizontal tabilizer inspired by the structure of the tails of birds that is expected to yield significant advancements in both stability and aerodynamic efficiency, with the potential to revolutionize MAV technology."
Acceso Abierto
Computational Study of Aerodynamic Effects of the Dihedral and Angle of Attack of Biomimetic Grids Installed on a Mini UAV
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-12-29) Bardera, Rafael; Rodríguez Sevillano, A.; Barroso, Estela; Matías García, J. C.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Defensa de España
In this paper, a numerical analysis of a biomimetic unmanned aerial vehicle (UAV) is presented. Its wings feature three grids at the tip similar to the primary feathers of birds in order to modify the lift distribution over the wing and help in reducing the induced drag. Numerical analysis using computational fluid dynamics (CFD) is presented to analyze the aerodynamic effects of the changes in dihedral and angle of attack (with respect of the rest of the wing) of these small grids at the tip. The aerodynamic performances (lift, drag, and efficiency) and rolling capabilities are obtained under different flight conditions. The effects of changing the dihedral are small. However, the change in the grid angle of attack increases aerodynamic efficiency by up to 2.5 times when the UAV is under cruise flight conditions. Changes to the angle of attack of the grids also provide increased capabilities for rolling. Finally, boundary values of the pressure coefficient and non-dimensional velocity contours are presented on the surfaces of the UAV, in order to relate the aerodynamic results to the aerodynamic patterns observed over the wing.
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Helicopter Rotor Ground Effect and Frigate Interaction Investigated by Particle Image Velocimetry
(American Institute of Aeronautics and Astronautics (AIAA), 2021-08-23) Bardera, Rafael; Matías García, J. C.; Instituto Nacional de Técnica Aeroespacial (INTA)
Helicopter maneuvers on frigates develop an essential role during military operations. However, the complex flow generated by the frigate bluff-body shapes and the interaction with the helicopter downwash during the recovery process must be studied in detail. In addition, the ground effect can also affect helicopter performance during the maneuver. This study aims to use particle image velocimetry in wind tunnel to analyze the airflow generated by a 1:100-scaled helicopter rotor of the Sea King SH-3 navy helicopter isolated and with the presence of a full and a partial ground to consider the ground effect at different heights. Once the rotor has been studied, experimental tests were carried out of the rotor working next to a frigate model during the recovery maneuver. The measured velocity indicates that the flow asymmetry below the rotor can increase with the proximity to a partial ground distance up to 1.39 times. During the study of the rotor for the frigate landing approach, the downwash asymmetry is also important and changes abruptly the tendency during the last phase of the maneuver. It can lead to dangerous instabilities and problems for the helicopter pilot during the hovering over ships.

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