Browse Topic: Wings
The front wing of a Formula 1 car is one of the most important aerodynamic components in design development. Particularly, as it is the first to interact with the upcoming airflow, the aerodynamic flow structures generated will have a strong interaction with the remainder of the car’s components. In 2026, the Fédération Internationale de l’Automobile will introduce new regulations that incorporate new aerodynamic philosophies for the front wing, including active aerodynamics. This paper presents a design methodology study for the development of a Formula 1 2026 front wing, compliant with Issue 9 of the technical regulations. A computational-based, structured optimisation series was conducted to enhance the aerodynamic performance of a front wing concept with a focus on improving downforce, maximising efficiency, and enhancing trailing flow for the remainder of the car. The final front wing concept at 40%, running at 30 m/s, generated 189 N of downforce and 19 N of drag. Active
A research team developed a smart strake system that dynamically adapts to flight conditions, showing a promising drag reduction in the wind tunnel with respect to passive strakes. This approach has the potential to save airlines hundreds of kilograms of fuel per flight. University of Washington Department of Aeronautics & Astronautics (A&A), Seattle, WA For decades, aircraft have carried a fundamental compromise between their engines and wing flow interactions by using strakes. These are small fins attached at the sides of engine nacelles that generate helpful vortices during takeoff and landing that boost lift and avoid stall, but create unwanted drag during cruise flight. Now, seven William E. Boeing Department of Aeronautics & Astronautics (A&A) undergraduates have advanced a solution that improves this trade-off, achieving up to 33 percent drag reduction, on the limited tested conditions, during cruise while maintaining critical safety benefits at high angles of attack. The team
Between the 1920s and 1930s, aluminum started replacing wood as the primary material in aircraft construction and soon became the backbone of modern aviation. Its popularity stemmed from a combination of properties, high strength-to-weight ratio, corrosion resistance, and ease of forming that made it ideal for demanding aerospace applications. Throughout much of the 20th century, high-strength aluminum alloys dominated aircraft design, accounting for 70-80 percent of commercial airframes and more than half of many military aircraft. Even after the introduction of fiber-polymer composites in the early 2000s, aluminum has remained a critical material because it continues to offer the strength, lightness, and versatility needed for modern aviation. Industry forecasts predict that commercial air travel will double in the next 25 years, which means more pollution will be released into the atmosphere. One way to help reduce these emissions is by building airplane fuselages and wings with
Mathematician hopes to harness principles of dynamic soaring for long-distance flights. University of Cincinnati, Cincinnati, OH How does one of the biggest birds in the world spend so much time in the air? Albatrosses have 11-foot wingspans that carry them across oceans. But it's how they use these wings that makes them world-class flyers, according to a University of Cincinnati aerospace engineering professor.
In a groundbreaking achievement, the 101st Combat Aviation Brigade, 101st Airborne Division (Air Assault) earlier this year became the first unit to successfully use the Mobile User Objective System (MUOS) function of the Army/Navy Portable Radio Communications (AN/PRC) 158 and 162 radios for conventional rotary wing operations. The trailblazing accomplishment occurred as the brigade continued its mission of providing support to ground forces, April 9, 2025.
In a groundbreaking achievement, the 101st Combat Aviation Brigade, 101st Airborne Division (Air Assault) earlier this year became the first unit to successfully use the Mobile User Objective System (MUOS) function of the Army/Navy Portable Radio Communications (AN/PRC) 158 and 162 radios for conventional rotary wing operations. The trailblazing accomplishment occurred as the brigade continued its mission of providing support to ground forces, April 9, 2025. The MUOS function, of the AN/PRC-158 and 162 radios, operates by transmitting ultra-high frequency radio waves through a constellation of satellites to create a steady communications network. MUOS is a component of a bigger Integrated Tactical Network (ITN).
Electric Vertical Take-Off and Landing (eVTOL) aircraft, conceptualized to be used as air taxis for transporting cargo or passengers, are generally lighter in weight than jet-fueled aircraft, and fly at lower altitudes than commercial aircraft. These differences render them more susceptible to turbulence, leading to the possibility of instabilities such as Dutch-roll oscillations. In traditional fixed-wing aircraft, active mechanisms used to suppress oscillations include control surfaces such as flaps, ailerons, tabs, and rudders, but eVTOL aircraft do not have the control surfaces necessary for suppressing Dutch-roll oscillations.
This paper carries out experimental investigation of propeller and wing interactions under various geometric variations such as the horizontal and vertical distance between the propeller axis and the leading edge of the wing under different angle of attack conditions for a half wing setup for a wing made of symmetric airfoil. Rotor and wing performance is measured using independent six-component load cells. Through this study it is identified that for a wing made of symmetric airfoil optimal aerodynamic performance is significantly influenced by the position of the propeller. Positioning the propeller near the leading edge (x/c = 0.25) and on the negative side of the y-axis (y/c = −0.75) yields the best lift-to-drag ratios and enhanced lift, particularly in the moderate α range (4°–6°). Forward movement of the propeller along the x-axis (towards x/c = 0.75 or 1.00) increases drag and adversely affects performance.
By its seventh flight after the first take-off, the RACER (Rapid And Cost-Effective Rotorcraft) demonstrator smoothly reached the targeted 220kts speed in stabilized forward flight, validating the high-speed compound architecture developed by Airbus Helicopters in the frame of Clean Sky 2 programme. During the flight envelope exploration, the dynamic behavior of the main rotor was carefully assessed, by monitoring the vibratory loads and validating its aeroelastic stability. Particular care was taken to validate the predicted stability domain of the Dual Rotor phenomenon, a particular case of flap-lag coupling associated with high-speed flight conditions. This paper presents the most significant results shaping the success of RACER flight test campaign. After having introduced the theoretical background and the associated analytical equations, the simulation framework based on the comprehensive analysis tool STORM is presented to discuss the numerical resolution of the stability
Aeroelastic stability prediction is critical to the successful design, development and flight testing of rotorcraft. As configurations reach higher speeds, new challenges in high Mach number unsteady aerodynamic modeling need to be addressed, especially for higher frequency aeroelastic modes with significant coupling. In this paper, Linear Unsteady aerodynamics and Leishman-Beddoes attached flow models are applied and compared to 2D CFD (airfoil) and 3D CFD/CSD (rotor) analysis for operating conditions of interest. The Leishman-Beddoes model demonstrates improved agreement with CFD data. In the 2D assessment, RCAS is used to model a representative airfoil undergoing prescribed pitch and heave oscillations. CFD results are presented to compare each model (Linear Unsteady and Leishman-Beddoes). In the 3D assessment, a full rotor CFD/CSD test case is evaluated for aeroelastic stability and compared to RCAS standalone analysis. The RCAS rotor structural model is coupled with the HELIOS CFD
Developed in the frame of the European Clean Sky 2 program, the RACER High Speed Helicopter Demonstrator of Airbus performed its maiden flight on April 25th, 2024. In the continuity of the previous high-speed demonstrator X3 (1st flight in 2010) the RACER is a 7/8t (15000 / 18000 lb) class compound helicopter powered by two SHE Aneto-1X engines, including a wing and two propellers. The tail rotor is removed as the two propellers control the yaw axis by differential thrust. At flight 07, with its initial default settings, it reached a true airspeed of 227 kts in level flight, exceeding its objective of 220 kts.
This paper investigates the influence of wing-propeller aerodynamic interactions on the aeroelastic damping of a wing-propeller system. The system is modeled in the Rotorcraft Comprehensive Analysis System using the viscous vortex particle method for the propeller aerodynamics and the uniform inflow model for the wing. The aeroelastic damping characteristics are identified from simulated time-history data using a recently developed method that captures amplitude effects due to system nonlinearity. The damping characteristics identified using conventional methods based on linear assumptions are also presented for comparison. The results show that, at lower airspeeds, the local damping decreases with increasing propeller hub displacements, both with and without aerodynamic interactions. This amplitude-dependent behavior cannot be captured by conventional damping identification methods that average amplitude effects. Amplitude-dependent trends are exacerbated by wing flexibility. However
An OVERFLOW simulation of a four-bladed rotor in hover is performed, and the resulting steady-state solution for the boundary layer over a rotating blade is analyzed by means of linear stability methods. The techniques employed are the Linear Stability Theory, the Parabolized Stability Equation, and the spanwise BiGlobal analysis. The unstable modes in the boundary layer of the rotating blade are analyzed in comparison with those typically observed in swept wings. The effect of the Coriolis force and the spanwise gradient of the free stream velocity are taken into account, and their influence on the instabilities is evaluated. It is shown that periodic boundary conditions in the spanwise BiGlobal analysis work adequately for a sufficiently small fraction of the length of the blade (~ 1:2%), while increasing the domain would require an alternative approach to the boundary conditions.
A method for the parameterization of an arbitrary airfoil using a transformation and Chebyshev polynomial interpolation is investigated. The airfoil was transformed into a continuous function using the Class Shape Transformation. A square root spacing was used to smooth out the slope discontinuity found at the origin. This mapping reduces oscillations in the polynomial interpolation caused by the slope discontinuity at the origin. Interpolating a range of NACA 4-digit series airfoils showed that these airfoils could be accurately represented with as little as 10 polynomial terms. However, problems arise with the Class Shape Transformation when trying to parameterize non-analytically defined airfoils. The transformation expects the behavior of the leading edge to be perfectly elliptic, and any deviation from this requirement leads to the divergence of the Class Shape Transformation. As a result, parameterizing with polynomials becomes infeasible for some airfoils. To address this, a
A hybrid RANS/LES simulation of the Ideally Twisted Rotor (ITR) in hover was interrogated to identify bluntness vortex shedding (BVS) and determine the contribution to the predicted rotor broadband self-noise. Three rotor blade stations were extracted to study spanwise variations in the BVS shedding frequency and amplitude. Corresponding 2-D airfoil simulations were performed to evaluate a simplified modeling approach that effectively isolates BVS. The BVS shedding frequencies predicted by the 2-D airfoil simulations differed by less than 2% from the corresponding rotor stations in the 3-D simulation. The increased computational cost incurred by performing 3-D airfoil simulations did not lead to a worthwhile increase in simulation fidelity. Farfield noise was predicted for the three rotor stations and the 2-D airfoil simulations, and trends in frequency agreed well. The 2-D approach overpredicted the 3-D peak amplitudes by 5 - 10 dB. This work demonstrates that 2-D hybrid RANS/LES
This paper presents an experimental and analytical investigation of whirl-flutter stability in tiltrotor aircraft, focusing on the influence of pitch-flap coupling on stability boundaries. Wind-tunnel tests were conducted using the TiltRotor Aeroelastic Stability Testbed (TRAST), a semi-span model designed for test-analysis correlation. This study examines variations in pitch-flap coupling and compares measured frequency and damping trends with predictions from RCAS and CAMRAD II. Results indicate that less pitch-flap coupling increases stability, with both analytical models capturing general trends. The analysis accurately predicts the wing inplane mode stability, but larger deviations are observed in the vertical bending mode, suggesting missing physical effects in the modeling approach. Differences in damping trends at higher speeds indicate that improvements in modeling may be necessary to refine stability predictions. These results provide valuable insights into the capabilities
The paper presents a general framework for building an aeromechanic model in FLIGHTLAB, suitable for high fidelity, pilot-in-the-loop simulator. The focus is on aerodynamic modeling of AW609 tiltrotor in Airplane Mode flight regime. The framework can be extended to helicopter and conversion modes with additional considerations for rotors-airframe aerodynamic interference. It can also be adapted to different tiltrotor geometries, with some adjustments depending on their peculiarities. The model uses Blade Element Theory loads evaluation of lifting surfaces, corrected with tabulated distributed loads to tune FLIGHTLAB predictions against high-fidelity aerodynamic references. Bluff bodies are modeled using force and moment tabulated data. Verification was conducted against reference data in wind tunnel mode and against flight data in trim analysis. The proposed method allowed to match lift distribution on slender bodies, as well as lift and drag integral loads, with aerodynamic references
This paper explores novel airfoils for rotorcraft applications using a gradient-free, multi-objective genetic algorithm with 2D URANS simulations. The study considers dynamic kinematics at a Reynolds number of 5×105 and a mean Mach number of 0.35. Two optimization scenarios are analyzed: 1) pre-stall kinematics (0° ≤α ≤10°) and 2) dynamic stall kinematics (0° ≤ α ≤ 20°). The paper compares two objective functions: f1, based on the cycle averaged lift, and ˜ f1, which modifies f1 by penalizing hysteresis in the lift coefficient. The effects of uniform vs. fluctuating freestream velocity and reduced frequency on optimal airfoils are also discussed. The proposed optimization approach has resulted in novel airfoil shapes that are characterized by a drooped nose, with a convex surface on the aft upper surface similar to a reflex camber in pre-stall kinematics and less unsteadiness in the air loads for the optimized airfoils under the dynamic stall kinematics.
The advanced air mobility (AAM) sector is using novel aircraft configurations and distributed electric propulsion to revolutionize aviation. These concepts require rotors that are efficient in vertical and forward flight. A concept that shows potential for this application is the slotted, natural-laminar-flow (SNLF) airfoil due to its high lift and low drag characteristics. This work explores the impacts of using an SNLF airfoil on an AAM rotor. Comparisons are made with blade element momentum theory (BEMT) method and computational fluid dynamics (CFD) to study the impact on the performance of an isolated rotor in hover. It is found that the rotational speed of the SNLF rotor can be reduced by 8% while still maintaining the necessary thrust for trim. A rotor broadband noise prediction shows that the slower SNLF rotor is 1-2dB quieter in terms of overall sound pressure level. Comparison of both rotors in forward flight indicates that the SNLF rotor consistently has a 1-2% higher
This paper presents findings from a joint computational-experimental venture that seeks to advance the physical understanding and validation-quality database for a model-scale generic tractor proprotor–wing system during the tiltrotor conversion maneuver. This study evaluates the interactions in a quasi-static manner for various proprotor tilt angles (θ) across the tiltrotor conversion maneuver. Independent experimental measurements of the wing and proprotor loads accompany synchronous wing surface pressure measurements along with stereoscopic particle image velocimetry flow field measurements at discrete spanwise locations. High-fidelity computational fluid dynamics simulations leverage the multi-disciplinary rotorcraft simulation tool CREATE™-AV Helios to assess the interactional aerodynamics of the proprotor–wing configuration across the tiltrotor conversion maneuver. Computational simulations use a newly implemented Helios module to trim to the experimental proprotor thrust
Owls are fascinating creatures that can fly silently through some of the quietest places. Their wings make no noise while flying, enabling them to accurately locate their prey using their exceptional hearing ability while remaining undetected. This unique ability depends on many factors and has long been a hot research subject.
The mystery of how futuristic aircraft embedded engines, featuring an energy-conserving arrangement, make noise has been solved by researchers at the University of Bristol. University of Bristol, Bristol, UK A study published in Journal of Fluid Mechanics, reveals for the first time how noise is generated and propagated from these engines, technically known as boundary layer ingesting (BLI) ducted fans. BLI ducted fans are similar to the large engines found in modern airplanes but are partially embedded into the plane's main body instead of under the wings. As they ingest air from both the front and from the surface of the airframe, they don't have to work as hard to move the plane, so it burns less fuel. The research, led by Dr. Feroz Ahmed from Bristol's School of Civil, Aerospace and Design Engineering under the supervision of Professor Mahdi Azarpeyvand, utilized the University National Aeroacoustic Wind Tunnel Facility. They were able to identify distinct noise sources originating
A study published in Journal of Fluid Mechanics, reveals for the first time how noise is generated and propagated from these engines, technically known as boundary layer ingesting (BLI) ducted fans. BLI ducted fans are similar to the large engines found in modern airplanes but are partially embedded into the plane’s main body instead of under the wings. As they ingest air from both the front and from the surface of the airframe, they don’t have to work as hard to move the plane, so it burns less fuel.
This paper presents the preliminary results of the recent whirl flutter wind tunnel test campaign performed within the Advanced Testbed for TILtrotor Aeroelastics (ATTILA) project. The Froude-scale ATTILA testbed consists of a semi-span wing with powered tip-mounted proprotor reflecting the proprietary design of the Next Generation Civil TiltRotor (NGCTR). An overview of the ATTILA testbed, wind tunnel test procedures, team organisation and preliminary flutter results are presented. In line with pre-entry dynamic characterization tests, the wind-on test activities in the DNW Large Low-speed Facility (LLF) revealed notable force-dependent nonlinearity in the modal characteristics of, particularly, the wing torsion mode. Further dimensionality was added by early observations that damping in the rotor gimbal degree of freedom, attributed to stiction in the blade pitch mechanism, had the potential to substantially contribute to the damping of the fundamental wing-pylon modes. Nevertheless
This paper analyses the possibility of using photovoltaics as additional energy provider for small to medium-sized eVTOL UAVs. A simplified model for eVTOL UAVs, which covers all relevant areas of aircraft design, including aerodynamics, structural mechanics, propulsion and systems modelling, is presented. Sensitivity studies covering various design parameters, such as airfoil, wing geometry and propulsion system selection are performed to show their influence on the configurations' performance. The first result of this paper is, that a photovoltaic powered configuration can outperform a battery electric and it can be worth the effort to implement the solar cells. To achieve this, the aircraft needs to be as aerodynamic efficient as possible. Also higher efficiency solar cells increase the possible performance. Additionally there is a big influence of the time of year and the latitude onto the performance. Secondly a multi mission study is performed. This uses a more detailed model, as
The succession of the BK117 D-2 main rotor concept from the semi-rigid rotor to the BK117 D-3 bearingless main rotor (BMR) system, derived from the H135, held many new and innovative additional benefits in its wake. Although the H135 system is the best on the market regarding maintenance effort and maintenace cost (DMC), it was the purpose to push this benchmark even further. To achive additional benefits, three major improvements needed to be successfully implemented and none of them was a given. First to mention is the concept of the blade being separated in three parts. In case of foreign object damage (FOD), most of the time only the outer part needs to be repaired. In parallel a new possibility to fold the system with a full folding capacity was introduced with the challenge to realize the extremely low DMCs of the H135, in a decisively bigger helicopter and to benefit from the experience of millions of flight hours and thousands of helicopters operated throughout the world
Airfoil optimization for rotor blades is a critical endeavor aimed at enhancing aerodynamic performance and reducing noise. This paper employs a Kriging surrogate model combined with a multi-objective genetic algorithm to optimize thrust, power, and broadband noise. Three airfoil parameterization methods including ParFoil, PARSEC, and CST are compared when used to generate various airfoil shapes for the surrogate model and optimization process. We utilize low-fidelity aerodynamic tools such as XFOIL and blade element momentum theory for aerodynamics. In addition, acoustic modeling is conducted using Lee's wall pressure spectrum model alongside Amiet's trailing-edge noise model. The paper focuses on small-scale rotor configurations, specifically an ideally twisted rotor using the NACA 0012 airfoil and a modified XV-15 blade. Both blades are used as baseline models for hover optimization. The optimization of the ideally twisted rotor across various parameterization methods demonstrates a
This paper investigates optimal wing arrangements for electric Vertical Take-Off and Landing (eVTOL) aircraft, leveraging on their design flexibility with electric propulsion system. The study employs a multidisciplinary approach with the objective of integrating aerodynamic analysis, static and dynamic stability assessments, and pilot feedback to evaluate various wing configurations. Analytical techniques were adopted to evaluate aerodynamic performance and static stability, while experimental flight testing on scale models was conducted to validate these findings. Additionally, the Cooper-Harper rating system was introduced to capture pilot perceptions of aircraft handling qualities. Results inform eVTOL designers on wing arrangements that offer enhanced aerodynamic efficiency, stability, and handling qualities, ultimately expanding the operational scope and applications of eVTOL aircraft. The study concludes the versatility of the high aspect ratio conventional wing on eVTOL
This paper addresses the aerodynamic interaction effects between a wing and a propeller on the whirl flutter boundary. A wing-pylon model with a propeller is defined and modeled in the Rotorcraft Comprehensive Analysis System, considering both a flexible and rigid wing. The aerodynamic interaction effects on the whirl flutter boundary between the wing and the propeller are examined for various inflow models, including the viscous vortex particle method (VVPM), uniform inflow, and dynamic inflow on the propeller, and uniform inflow and vortex wake on the wing. Results show that the whirl flutter boundary is overestimated when the propeller is modeled with the VVPM and aerodynamic interaction effects are neglected. The impact is more prominent for a flexible wing-pylon model. Other propeller aerodynamic inflow models and their associated interaction effects alter the damping trend and increase the flutter speed on a flexible wing-pylon model only, highlighting the need to model propeller
NASA's 4th New Frontiers Mission is the Titan Dragonfly relocatable lander. This coaxial quadrotor vehicle will be launched on a rocket to Titan in 2028. Following a gravity assisted Earth flyby and an approximate 6-year transit, Dragonfly will enter the Titan atmosphere around 2034 with the goal of exploring Titan's pre-biotic chemistry and habitability. The multirotor design for this unique application has continually evolved since 2016 with constraints such as Titan's cryogenic atmosphere at 95 Kelvin (-288 F), gravity 14% that of Earth's, atmospheric density 440% of standard sea-level air, and the inability to test the entire system together under all these conditions until the first flight on Titan. This paper focuses on rotor design aspects of the Dragonfly lander and introduces a novel framework for multirotor design optimization considering multiple flight conditions. The methodology leverages machine learning methods and is demonstrated in the context of Dragonfly. A new
The tiltrotor whirl flutter stability of a gimballed hub and a hingeless hub are investigated using multibody dynamics simulations. A semi-span wind tunnel tiltrotor model are developed using the multibody dynamics code: Dymore. CAMRAD II predictions are used to correlate the Dymore predictions of the baseline tiltrotor characteristics. The rotor structural frequencies of the gimballed tiltrotor and the hingeless tiltrotor are compared between Dymore and CAMRAD II predictions with good agreements. CAMRAD II model of the baseline TRAST gimballed tiltrotor is used for correlating the whirl flutter stability with that of the Dymore model. Overall good agreements are shown for both the frequencies and damping ratios of all three wing modes. The effects of key design variables, such as blade stiffness, rotor RPM, and ƍ3 on tiltrotor whirl flutter stability of both hubs are studied.
An aeromechanics analysis of a Mach-scaled rotor with lift compounding was conducted to understand the impact of various wing configurations on performance and loads. An assessment of the single retreating side wing and dual wing configurations was conducted for advance ratios up to μ = 0.7, two wing incidence angles (4° and 8°), and three rotor shaft angles (-4°, 0°, and 4°). Aircraft performance, control angles, blade structural loads, hub vibratory loads, and aerodynamic interactions between the rotor and wing were evaluated using the University of Maryland Advanced Rotorcraft Code (UMARC). Additionally, UMARC coupled rotor-wing analysis was validated with wind tunnel data of a lift and thrust compounded rotor. The study shows that the single wing configuration is beneficial for peak vehicle performance (L/D), though the dual wing configuration minimizes blade loads. The single wing configuration observed a 7% greater wing L/D than the dual wing configuration for the same 8° wing
This paper introduces ABC2, an advanced framework for rotor blade design optimization that can effectively consider the airfoil shape variations during optimization process. A major component of this framework is an reduced-order model (ROM) that leverages deep-neural-network techniques both for airfoil parameterization and performance prediction. Utilizing the UIUC airfoil database and a two-dimensional unsteady Reynolds-averaged Navier-Stokes (URANS) solver, the ROM can effectively control the airfoil shapes and predict the resulting aerodynamic performance across the wide range of flow conditions. A comprehensive aerodynamic solver is incorporated for blade design optimization. Enhancement of the fidelity of the comprehensive solver is achieved through the integration of a three-dimensional URANS solver, which also plays a crucial role in analyzing the aerodynamics of the optimized blade and uncovering its underlying physics. The competence of the present framework is demonstrated
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