Browse Topic: Electric aircraft
This paper develops an engineering concept and research framework showing how Cherokee MC2 (Mobile Command Center) and MVP (Mobile Vertipad Platform) can individually, and then as a combined system, resolve key operational and infrastructure challenges facing rotorcraft, eVTOL, VTOL, and UAS missions across civil, commercial, and military contexts. The investigation synthesizes current vertiport / vertipad design guidance, UAM and UTM operational architectures, and recent research on rotor downwash and degraded visual environment hazards to derive a deployable "vertiport node" architecture for austere and time-critical operations. MC2 is treated as the digital and procedural core enabling command, control, communications, data fusion, and manned–unmanned teaming, while MVP is treated as the physical landing interface enabling rapid, load-bearing, illuminated vertical-lift operations without fixed infrastructure. The primary contribution is a traceable topic-to-capability mapping supported by standards and research, plus a modeling, simulation, and optimization workflow to validate safety zones, capacity, scheduling, and resilience. Conclusions identify practical deployment pathways and research gaps for certification-aligned operations.
This study develops an efficient framework coupling the Lattice Boltzmann Method with the Actuator Line Method to evaluate the unsteady downwash/outwash of eVTOL aircraft. By incorporating a modified Prandtl loss function with geometric smearing correction, the framework accurately predicts velocity profiles and preserves unsteady vortices at lower computational costs than conventional RANS-based simulations. Analyzing three distinct eVTOL configurations sized for identical payload missions reveals that higher disk loading and multi-rotor interactions generate highly asymmetric, localized jet-like outwash structures, contrasting with the symmetric ground-level footprint of single rotor designs. Utilizing a 95th percentile velocity metric, transient peak hazards breach the regulated vertiport Safety Area boundary, extending up to 1.65 times the prescribed baseline limit. These findings demonstrate that time-averaged metrics underestimate physical hazards, highlighting the necessity for future guidelines to mandate configuration specific evaluations utilizing high-resolution unsteady flow data and robust statistical processing.
We present a nonlinear topology optimization framework for designing crash--tolerant rotorcraft substructures by maximizing plastic work under prescribed crush displacement and volume constraints. The quasi-static response is modeled using a rate-independent elastoplastic formulation to capture path-dependent inelastic deformation of metallic components. A path-dependent adjoint method is developed to efficiently compute sensitivities of accumulated plastic work, revealing a mechanistic decomposition into elastic stiffness, deviatoric response, and yield surface contributions. Optimized 2D and 3D subfloor structures develop emergent plastic hinge networks and distributed deformation paths, significantly enhancing energy absorption compared to uniform designs. The results demonstrate that topology optimization can directly embed energy-dissipating mechanisms into primary rotorcraft structures, providing a practical framework for crashworthy rotorcraft and eVTOL airframe designs.
The rapid expansion of electric aviation and eVTOL operations introduces tightly coupled challenges related to energy‑constrained aircraft design, battery and thermal management, mission planning, and the generation of certification‑relevant evidence. This paper presents an integrated simulation workflow developed by AVL, Unisphere, and blueflite that combines high‑fidelity electric powertrain and battery models with a guidance‑level, digital‑twin‑based 4‑D trajectory simulation driven by historical weather and operational constraints. At each mission time step, the trajectory layer provides time‑resolved environmental and routing conditions, while the system‑level models compute instantaneous power demand, state‑of‑charge evolution, and thermal response, enabling mission feasibility assessment under realistic wind, temperature, and airspace effects. The workflow is calibrated and validated using flight telemetry from blueflite's active eVTOL cargo aircraft development, ensuring alignment between simulation assumptions and real‑world mission execution. The validated framework is subsequently applied to seasonal route studies and large‑scale virtual flight campaigns spanning multiple regions and years, enabling statistically robust assessment of energy margins, thermal behavior, and mission‑duration variability. The results demonstrate how integrated, traceable simulation can bridge conceptual design and real‑world electric flight operations, supporting informed decision‑making by OEMs and operators in aircraft design, validation, and deployment planning.
Urban air mobility with electric Vertical Take-Off and Landing (eVTOL) aircraft faces critical micro-weather and infrastructure readiness challenges. This paper proposes a novel socio-technical solution: a tokenized gamification platform that crowdsources hyper-local wind and weather data to enhance operational resilience. We outline the safety gap left by traditional aviation weather systems (METAR, AWOS, ASOS) in urban environments, and leverage community engagement to fill it. The proposed system integrates with Unmanned Traffic Management (UTM) and Safety Management Systems (SMS) to validate user-contributed micro-weather observations, incentivize accurate reporting through tokens and skill-level progression, and feed data into AI-driven forecasts. Early proof-of-concept results indicate improved wind hazard detection and robust user participation. By aligning with emerging regulations (FAA, EASA, DGCA) and test frameworks, this crowdsourced micro-weather ecosystem shows potential to uplift eVTOL safety, build public trust, and support city-scale planning for advanced air mobility.
Rainwater accumulation and management are critical to the safety and reliability of drones and emerging eVTOL aircraft. Current industry practice relies on physical rain testing, such as RTCA DO-160, which defines rainfall conditions for environmental qualification but is costly and difficult to apply during early design stages. This work presents a virtual rainwater assessment framework using Smoothed Particle Hydrodynamics (SPH) simulation in PreonLab. Using an early-stage APELEON cargo drone as a reference case, the method predicts rain impingement, surface runoff, pooling, and ingress under representative rainfall conditions. The meshless SPH approach enables direct simulation of complex geometries and transient interactions without mesh generation, while also supporting rotating components and arbitrary orientations. Results identify key mechanisms governing water transport, including geometry-driven runoff, hinge-related ingress, and droplet deflection from nearby structures. While the total water accumulated on the aircraft can reach on the order of several hundred grams, the amount entering the cargo space remain small. Localized moisture exposure highlights potential durability risks. The framework enables early design evaluation, parametric studies, and rapid assessment of mitigation strategies, supporting simulation-driven development and certification preparation for advanced air mobility systems.
A methodology was developed and validated to predict total noise from a 1/5th scale eVTOL rotor in hover by coupling 2D-RANS airfoil simulations with the comprehensive code, CHARM, for rotor loading, the acoustic code, PSU-WOPWOP, for tonal noise, and the broadband noise code, UCD-QuietFly, for broadband noise prediction. Improved sectional 2D aerodynamic inputs obtained from 2D-RANS simulations were used throughout the framework, replacing XFOIL-derived inputs to enhance the prediction accuracy of low Reynolds-number effects such as transition and laminar separation bubbles. Predictions were validated against measurements at Virginia Tech. Results indicate that turbulence model selection influences local boundary-layer development and sectional aerodynamic loading, producing modest differences in tonal noise at 4000 RPM (first BPF) and spectral differences of approximately 4 dB in broadband noise, while integrated OASPL shows slight sensitivity to turbulence model choice. At 2000 RPM, broadband noise dominates the total SPL, with transitional models predicting thinner boundary layers and reduced high-frequency trailing-edge noise. In addition, high-fidelity 3D-DDES simulations performed in OpenFOAM capture the mid-frequency noise content that is underpredicted by CHARM. Overall, the combined mid-fidelity broadband noise results and high-fidelity mid-frequency range noise results provide improved agreement with experimental spectra and demonstrate an effective approach for eVTOL rotor noise prediction.
The present study provides a detailed analysis of interactional aerodynamic effects present in the lift and cruise ROMEO demonstrator aircraft. A combination of high-fidelity unsteady Reynolds-averaged Navier-Stokes (URANS) simulations and mid-fidelity actuator disk and actuator line methods is applied to efficiently capture the dominant flow phenomena of a distributed electric propulsion configuration across multiple flight regimes. The mid-fidelity approaches are initially validated against fully-resolved propeller simulations to assess their accuracy and computational benefits. Subsequently, the influence of multi-propeller interactions on lifting arms and tail components is analyzed in hover, followed by an investigation of propeller-airframe interactions during forward and sideward hover maneuvers. A particular emphasis is placed on the modification of local inflow conditions and the subsequent distribution of loads. In the context of sideward flight, the present study explores the effects of asymmetric wake deflection on aerodynamic forces and moments. The findings indicate that propellers- airframe interactions exert a significant influence on aerodynamic performance, stability, and control behavior. This underscores the necessity for effective and precise modeling methodologies in the design of eVTOL systems.
Electric Vertical Take-Off and Landing (eVTOL) aircraft are poised to transform urban and regional mobility by offering zero-emission, congestion-free transportation. As regulatory frameworks evolve and advanced air mobility (AAM) gains traction, manufacturers are exploring propulsion strategies that improve range, power delivery, and overall system efficiency. A key challenge in eVTOL development is balancing range with payload capacity. While larger battery packs can extend range, they also increase system weight, reduce payload, and prolong charging times, limiting operational flexibility and turnaround time. Hydrogen fuel cells, supported by liquid hydrogen (LH₂) present a promising alternative for eVTOL propulsion. This study proposes a methodology for optimizing fuel cell propulsion systems tailored to eVTOL applications. A multi-physics modeling framework for eVTOL flight dynamics and propulsion system was developed, representing the target eVTOL configuration. For a defined flight path including vertical takeoff, hover, cruise, and landing, a Genetic Algorithm (GA) based optimization was conducted on propulsion system. The algorithm down-selected battery size, fuel cell stack specifications, and hydrogen tank capacity to meet mission requirements while minimizing propulsion system weight. The modeling framework was also used to evaluate trade-offs between payload and performance as functions of component sizing, battery chemistry and energy distribution strategy.
This study evaluates the impact of range extension on gross takeoff weight (GTOW) and energy cost for the NASA Lift+Cruise eVTOL configuration under present and near-term battery technology limitations. A baseline 8,210 lb, 6-passenger vehicle, originally designed for a 75-mile mission at 400 Wh/kg battery energy density, is shown to achieve only 15 miles at a more realistic 200 Wh/kg, largely due to the 20-minute SFAR reserve, which accounts for 64% of total onboard energy. To quantify the penalties of range extension, three sizing strategies are examined: fixed GTOW with payload trade-offs, fixed-geometry overloading, and fully co-scaled vehicle resizing. The co-scaled configurations reveal a strong nonlinear GTOW growth driven by an "adding battery to carry battery" effect, in which increases in GTOW necessitate heavier structure and propulsion, leading to a practical feasibility ceiling near 45 miles. Energy cost per payload-mile is found to be non-monotonic, reaching a minimum near 20-25 miles before increasing due to compounding weight penalties, contrary to trends predicted by fixed-weight analyses. Significant off-design penalties are also observed; operating a 40-mile aircraft on a 10-mile mission incurs a 72% energy cost increase relative to a co-scaled vehicle for 10 miles. Increasing battery energy density by 22.5% (to 245 Wh/kg) reduces the 6-passenger 40-mile design GTOW by 33% (from 13,712 lb to 9,187 lb) and shifts the optimal energy cost point outward to 30 miles. Ultimately, battery energy density is identified as the dominant parameter dictating the vehicle size, weight, performance, and the fundamental operational feasibility of UAM eVTOLs.
A method for evaluation of control derivatives is introduced for the purpose of rapid design evaluation of an electric, fixed-pitch multirotor aircraft during the conceptual pre-design phase. This explicit linearization methodology allows rapid co-design of the vehicle configuration and control allocation using the pseudo-inverse method. A multi-objective design analysis is conducted for a 12 rotor lift + cruise eVTOL configuration subject to hover power requirements, controllability, and tolerance to failure conditions. Generalizable design guidelines are found and presented for the cant and rotor spin direction of the lift + cruise aircraft. The benefits shown include the addition of direct lateral force control derivative, a major increase in yaw control derivative, and reconfiguration to accommodate any Two Engine Inoperative failure conditions. These are achieved through mixing anhedral and dihedral rotor cant within each quadrant of the wing, setting the spin direction so the component of thrust in the yaw axis is additive with the motor reaction torque, and having larger cant angles inboard and closer to the center of gravity. Additional analyses of stability characteristics are performed using DynaPyVTOL, a medium-fidelity flight dynamics analysis tool for any configuration.
A plethora of electric vertical takeoff and landing (eVTOL) aircraft development projects aim at developing passenger-carrying aerial vehicles for the purpose of providing point-to-point mobility services within and between metropolitan areas. The nascent passenger-carrying advanced air mobility (AAM) industry promises more affordable fares and seamless experience through innovation in aircraft design with the roll-out of these novel eVTOL within five years, new concepts of operations involving more automation, and higher utilization than with today's helicopter charter operations. AAM operators plan to leverage existing heliport facilities as well as trigger the development of new vertiports-some of them could be located on existing city real estate (e.g., high-rise buildings and parking garage rooftops). Moving vertical flight toward higher-intensity passenger operations and enabling a broad adoption as outlined during the dawn of AAM raise the question of accessibility. This includes access to the VTOL door sill for passengers with reduced mobility (PRMs), the VTOL boarding and deplaning process, and the feasibility of carrying their equipment onboard (including wheelchairs). This context includes the intermodal aspects of the first and last miles to the vertiport, the availability of equipment for facilitating PRM boarding, and the broad variety of aviation facilities that are served by VTOL aircraft-including small helipads and vertipads that are not all PRM-accessible. The study identifies key design and operational criteria for reducing barriers to an unhindered boarding and deboarding of VTOL aircraft-including helicopters and eVTOLs. It suggests mitigation in aircraft design and vertiport design. The analysis emphasizes the importance of incorporating accessibility considerations in the development of the different components of AAM in order to enhance operational safety, efficiency, and customer experience and to prevent adverse impacts on dignity, fairness, and mobility for all.
Electric vertical takeoff and landing (eVTOL) aircraft have rapidly emerged as a potential promising solution for sustainable and scalable urban air mobility. These vehicles are at a crucial stage of development, with sub-scale and full-scale flight test campaigns already underway. In forward flight, critical structural components of these variable RPM rotary wing aircraft can experience strong time varying aerodynamic loads. These components are lightweight, stiff, and often have very little intrinsic damping. Thus, from a life-cycle perspective, vibratory strains are of significant concern. This work investigates the use of Impact Dampers (IDs) in attenuating the bending and torsional response of a characteristic eVTOL boom. A computational reduced order model of an ID is developed using the Hunt-Crossley nonlinear contact model and linear beam finite elements. Predicted damper performance is compared with prior experimental measurements. Parametric studies are performed by varying key damper design variables, and predicted trends are shown to be consistent with experimentally observed behavior. The IDs attenuated the system structural response at resonance by 60.7% in bending and 52.1% in torsion, for a 5% mass penalty. Building on works presented at the 80th and 81st Vertical Flight Society Annual Forums, this publication is a next step towards establishing IDs as a viable multi-modal passive vibration control device in variable RPM multirotor vehicles.
This paper details comprehensive analysis modeling and analysis supporting the development of the Research Aircraft for eVTOL Enabling techNologies (RAVEN). An isolated rotor model was developed in CAMRAD II, and predictions of rotor performance and rotor aeroelastic stability were generated. The rotor stability predictions are part of assessing airworthiness of the RAVEN vehicle. The performance predictions were used to calibrate the surrogate model for the NASA Design of Rotorcraft (NDARC).
A high-fidelity computational study is conducted to investigate the aerodynamic behavior and flight response of an electric Vertical Take-Off and Landing (eVTOL) multirotor configuration using unsteady computational fluid dynamics (CFD) framework. Four simulation cases are considered to examine the vehicle aerodynamics under both prescribed and fully coupled conditions. Prescribed hover and forward-flight cases isolate rotor aerodynamics and rotor-airframe interactions under constrained kinematics. Six-degree-of-freedom (6-DoF) free-flight maneuvering simulations capture the coupled evolution of aerodynamic loads, vehicle attitude, and translational motion. The results demonstrate that the high-fidelity unsteady CFD framework, coupled with rigid-body dynamics, effectively resolves the tightly coupled aerodynamic–dynamic interactions inherent to eVTOL configurations. This work provides a foundation for future investigations into trim strategies, control modeling, and expanded flight envelopes.
This paper presents an initial handling qualities analysis of an Electric Vertical Take-Off and Landing (eVTOL) hexacopter. The analysis uses the Distributed Electric Propulsion Simulation (DEPSim), developed by Penn State University (PSU) and the Comprehensive Hierarchical Aeromechanics Rotorcraft Model (CHARM), developed by Continuum Dynamics, Inc. (CDI). The study focuses on evaluating a generic AAM hexacopter performing Handling Qualities Task Elements (HQTE) as defined by the DOT / FAA. A trajectory controller was developed to enable simulation of prescribed flight paths, allowing automated simulation of four HQTEs: Heliport Approach, Hovering Turn and Hold, Pirouette, Lateral Reposition and Hold. Design modifications incorporating lateral mast tilt and Direct Side Force Control (DSFC) were implemented to enhance yaw control and ride qualities. Piloted simulations were conducted at the PSU rotorcraft flight simulation facility using DEPSim, employing an Attitude Command Attitude Hold (ACAH) architecture with mode switching to Translational Rate Command / Position Hold (TRC / PH) and TRC plus DSFC modes. Two of the four HQTEs were tested in piloted simulations. Though formal ratings were not collected at this time, pilot commands and performance indicated that TRC / PH and TRC plus DSFC modes enhance handling qualities over ACAH mode. The DSFC control law was found to have substantially reduced roll attitude, which could potentially enhance visual cueing, pilot comfort, and pilot-perceived handling qualities.
This study presents a comprehensive analysis of single-rotor failure tolerance for a classical octocopter configuration, examining both hover and forward flight at the best range speed. Using a state-of-the-art eVTOL comprehensive analysis to retrim the octocopter post-failure, the redistribution of rotor thrust, torque, and power following individual rotor failures was quantified, along with resulting aircraft-level power penalties. In hover, orthogonal rotors to the failed rotor provide primary lift compensation, the opposing rotor operates mostly unchanged, and the four opposite spinning rotors primarily provide pitch/roll moment compensation. This results in a total aircraft level power increase of approximately 10.4%, roughly half that of comparable hexacopters. In forward flight, at best range cruise speed, load redistributions were again calculated for various individual rotor failures. In the worst case, a maximum individual rotor torque increase of 62% and power increase of 108% was observed, while total aircraft power requirements increased between 7-12%. These results demonstrate the fault-tolerant capabilities of octocopters and provide practical guidance for propulsion system sizing, energy management, and failure-case assessment on classical octocopters.
NASA is conducting investigations in Advanced Air Mobility (AAM) aircraft and operations, including the development of Urban Air Mobility (UAM) aircraft designs that can be used to focus and guide research activities in support of AAM. This report is an investigation of the impact of technology and mission variations on several of the NASA AAM concept aircraft: quadrotor, quiet single main rotor, side-by-side, and tiltrotor configurations, with turboshaft and electric propulsion variants for each. First, the mission and aircraft models of the baseline designs were reassessed and updated, including rotor geometry optimization, update of the rotor performance models, and disk loading optimization. For these eight designs, technology and mission excursions were performed. Relative to the calibration cases that can be considered examples of good design practice, the impact of the weight technology factors is significant. For the electric aircraft, there is a very large impact of battery specific energy (Wh/kg), and correspondingly a very large impact of mission range. The vision of Advanced Air Mobility is driven by missions that will enable new transportation capabilities. Hence it is appropriate to compare Concept Vehicles of different lift and propulsive architectures, all designed to accomplish the same UAM mission. It is also useful however to consider specific missions that can take advantage of the strengths of individual aircraft configurations. So alternate designs were also developed for the concept vehicles: for turboshaft aircraft, longer unrefueled range, including faster cruise speed for the tiltrotor; for electric aircraft, shorter range and more realistic battery weight.
Recent flight tests and simulations have suggested that the outwash from eVTOL air-taxis could be larger than conventional helicopters of equal weight and thus pose greater safety issues for their operation than previously anticipated. This has prompted interest in the analytical and experimental study of the aerodynamics related to multi-rotor aircraft outwash. This paper will describe work investigating some of the related issues, specifically (1) how wake models and wake model parameters impact outwash predictions in comprehensive rotorcraft analyses and (2) considerations when scaling results from model scale to full scale. This work will also compare outwash predictions for conventional and multi-rotor VTOL aircraft obtained with a Lagrangian free-vortex wake model and with an Eulerian velocity-vorticity grid based wake model.
eVTOL Pilot Perspectives, UAM, Challenges of Past V/STOL Aircraft, Modeling and Testing of Complexities Turning Unknowns into Knowns.
Presentation on Cargo eVTOL by Elroy Air
eVTOL Updates from Europe and China by Flying Pages GmbH
Towards Enabling Adoption at Scale
Advancing HIL and SIL Validation for eVTOL from Tip to Battery to Tail by Bloomy Controls
TVF 2026 Briefing on Advancing Autonomous Heavy-Lift Cargo and ISR Operations with Jaunt's Hybrid-Electric UAV
Anatomy of a HELIX Flight
From Test Flights to Revenue
Researchers at Embry Riddle Aeronautical University and Brazil’s Instituto Tecnológico de Aeronáutica (ITA) will combine forces on one of the main challenges of electric aircraft — controlling the heat spikes they generate at takeoff.
Researchers from Brazil are collaborating with a team at Embry-Riddle Aeronautical University to develop new methods for controlling heat spikes generated by electric aircraft during the takeoff phase of flight. Embry-Riddle Aeronautical University, Daytona Beach, FL Researchers at Embry Riddle Aeronautical University and Brazil's Instituto Tecnológico de Aeronáutica (ITA) will combine forces on one of the main challenges of electric aircraft - controlling the heat spikes they generate at takeoff. The collaboration is supported by a $450,000 National Science Foundation International Research Experiences for Students (NSF IRES) grant.
Manufacturers of fans/propellers using hydraulically-actuated pitch control claim energy efficiency gains up to 75% over fixed-pitch solutions. Unfortunately, the added cost, weight, reliability and maintenance considerations of hydraulic solutions has limited the introduction of pitch control for small-to-medium fans and propellers leaving a large market unserved by the efficiency gains associated with changing the pitch of a blade when the blade shaft’s speed changes. Pilot Systems International and Cool Mechatronics are developing an electromagnetically controlled pitch (EMCP) fan/propeller that will produce a new pareto optimal in size, weight, power, cost and cooling (SWaP-C2). The technology will substantially improve the efficiency of military ground vehicle cooling fans which is typically the third greatest power draw (~20kW)1 in the entire vehicle and provide critical performance improvements during silent watch. It will be a key enabler for the electrification of aircraft.
Aeromarine at 2025 Electric Aircraft Symposium
Advanced Safety Architecures for eVTOL Motor Drive Systems
EVTOL Developments at Horizon Aircraft
Electric Aircraft Charging Evolution Lessons from Automotive Charging
FRASCA International Training Requirements EVTOL
Electric vertical take-off and landing vehicles are proposed as a viable solution for urban air mobility due to their potential for reducing carbon emissions, noise, and operational costs. However, the shift towards electrified aircraft introduces new thermal management issues due to the excess heat generated by electric motors and power electronics. This heat is challenging to dissipate during the mission, resulting in transient motor temperatures, especially during high-power mission segments. In addition, electrified aircraft also encounter design challenges associated with the fixed weight of electric motors and batteries. To address these challenges, this work presents a multifidelity framework for performing shape optimization of an electric motor subject to performance, geometric, and thermal transient constraints. A preliminary sizing of the electric motor is performed using a low fidelity Fourier series model. Next, the sizing is refined by utilizing a coupled electromagnetic-thermal finite element model of the the motor physics. To demonstrate the framework, a numerical optimization is performed for a hover hold mission with a relevant scale eVTOL vehicle, reducing the structural mass of the motor by 2.7kg while ensuring power and thermal constraints are satisfied.
Researchers at the National Aeronautics and Space Administration (NASA) have conducted a series of module-level 50-ft dynamic drop tests on electric Vertical Take-off and Landing (eVTOL) Energy Storage Systems (ESS) for the generation of dynamic impact data to support standards developments. The tests were conducted on zero-state-of-charge Electric Power Systems (EPS) Electric Propulsion Ion Core (EPIC) modules at the National Institute for Aviation Research (NIAR), utilizing the NIAR outdoor drop test setup and conducted by NIAR test personnel. Four total tests were conducted on modules oriented in four different orientations. During initial post-test inspections at the drop facility, it was observed that the modules experienced varying amounts of damage in various locations and forms. The damage was quantified to the maximum extent possible via photogrammetric methods such as digital image correlation and marker tracking. Post-test modules were then disassembled, and forensics were conducted, which involved inspections into various containment structures and the cells themselves. A scoring rubric was developed in order to utilize a common methodology to quantitatively assess the damage incurred into each module as way of determining the least and most amount of damage present. Results in the form of post-test inspections, digital image correlation deformations, and scoring rubric values will be all presented, along with proposed paths forward for future work.
The performance and acoustics of a scaled propeller designed for an eVTOL vehicle were investigated in axial and edgewise flight. The measured performance compared well with BEMT predictions in axial flight conditions. The noise produced by the propeller is dominated by broadband noise sources, where there is evidence of contributions from blade wake interaction noise, turbulent boundary layer trailing edge noise, and laminar boundary layer vortex shedding noise. The directivity of the noise was found to be dependent on the advance ratio. Beamform maps also identified changes in the dominant noise source at different observer locations as a function of advance ratio.
This paper demonstrates methods of aircraft sizing, flight dynamics modeling, and performance analysis using a lift+cruise concept vehicle with an electric powertrain and variable-speed rotors. The central focus is the development of methods to relate the aircraft design sizing constraints to achievable maneuverability and predicted handling qualities. A toolchain is demonstrated that performs aircraft sizing, mass moment of inertia estimation, powertrain modeling, trim optimization, dynamics linearization, handling qualities prediction, and quantification of achievable maneuverability under both nominal conditions and control effector failures. A convex optimization problem framework is introduced to compute agility bound estimates without requiring control system design or control allocation, potentially supporting rapid design iteration as well as early detection of deficiencies and undesirable operating conditions. This analysis is supplemented with more conventional methods of analysis to provide additional perspective and observations. Overall, the results suggest that each modeling and analysis element in the demonstrated toolchain adds significant value, with the combined approach supporting a more efficient and comprehensive exploration of trade-offs within the design space.
This paper presents handling qualities (HQs) research findings for electrical Vertical Take-off and Landing vehicles. Testing in the Vertical Motion Simulator (VMS) investigated handling qualities of vehicle configurations having a degraded powertrain. Powertrain components, including batteries and electric motors, can degrade as the vehicle is flown. This paper investigates the impact of low battery charge and high motor temperature degradations on the pilot's ability to execute precise maneuvers. Pilot comments and ratings that were collected from four rotorcraft test pilots in VMS testing are used to quantify the effects that powertrain degradations had on the HQs of the vehicle.
This paper presents the development and implementation of a complete flight control architecture for a 200kg-class tilt-wing eVTOL aircraft, designed and tested by Dufour Aerospace. The system enables fully automated flight across all regimes, including hover, transition, and cruise. A modular control architecture is described, incorporating a unified vehicle controller, envelope protection, and a guidance system. The control design leverages classical and modern techniques, including model-based synthesis, control allocation, and gain scheduling. A structured software development and validation pipeline is outlined, combining simulation, software- and hardware- in-the-loop testing, and flight testing on both subscale and full-scale platforms. Results from recent autonomous flight trials of the Aero2 aircraft demonstrate precise trajectory tracking and robust performance. The presented approach highlights the feasibility of rapid development cycles while maintaining high standards of safety and reliability for certifiable eVTOL platforms.
To document noise characteristics and provide validation data for acoustic modeling of rotor systems appropriate for eVTOL/UAM aircraft, the authors performed an outdoor static test of a subscale 5-blade proprotor. The testing was carried out as part of a program to demonstrate feasibility and overall performance of a quiet proprotor system in support of the eVTOL industry. The authors designed a low-tip speed proprotor to approximate performance required by a 4-5 passenger UAM vehicle. A driving design feature was low-tip speed operation (Mtip ˜0.27) at system disk loadings of 7 to 8 psf (˜3.7 N/m2). The test article was designed as a ground adjustable pitch 5-blade proprotor, with aerodynamic and acoustic data collected in outdoor static hover testing. The test article diameter of 3 feet (0.91 m) represented a scale factor of approximately 30% to 40% compared to vehicles currently in operation or development. The aerodynamic performance in hover was consistent with other rotor systems tested in the past by the authors (Figure of Merit ˜0.72-0.75), and the effects of naturally occurring turbulence on rotor acoustics were measured using a 180-deg arc array of ground plane microphones at the Virginia Tech Drone Park test facility. The paper closes with a prop diameter scaling investigation using lattice-Boltzmann method CAA with and without atmospheric turbulence.
Electric aviation is advancing rapidly, with aircraft from manufacturers like Joby and Archer well on their way to certification, aircraft electrification will continue and begin to apply to larger aircraft. To support larger electrified rotorcraft, rotors will need to grow if disc-loading and hover efficiency are to be maintained. A consequence of this is the need to reduce rotor speed to maintain an acceptable acoustic signature, especially for operation in urban environments. Most current applications utilize radial flux motors, sometimes with a reduction gearbox. Gearboxes can improve overall propulsion system power density by enabling higher motor speeds but are generally not preferred as they introduce additional potential failure modes and maintenance schedules. In this paper a holistic approach is used to understand the trade-offs between rotor and motor and their consequences on propulsion system power density.
The transition phase of eVTOL aircraft poses a challenge in balancing energy efficiency and stability. This study presents the development and evaluation of an automatic flight control system for eVTOL transition phases, focusing on minimizing energy consumption while ensuring robust performance. The control architecture implements a hybrid response type combining Translational Rate Command below 5 knots and Acceleration Command Speed Hold above 5 knots, with control allocation dynamically adjusted based on airspeed and rotor shaft angle. Stability analysis reveals surge mode instability at high shaft angles due to negative speed stability derivatives, stabilized through carefully tuned feedback control. The system demonstrates Level 1 handling qualities against bandwidth, quickness, and disturbance rejection criteria when evaluated against MIL-DTL-32742 and MIL-STD-1797B standards. Simulation results verify the control system's ability to maintain precise acceleration/deceleration rates and attitude control while ensuring passenger comfort through limited pitch excursions. The control strategy achieves minimum energy transitions by locking rotor shaft angles to optimal schedules while avoiding excessive hub moments. Flight test maneuvers developed specifically for conversion phases confirm the system's capability to execute efficient transitions within defined performance boundaries. This research establishes a framework for certifiable eVTOL flight control systems that balance energy efficiency with robust performance across diverse flight regimes.
This paper presents insights into a comparative approach to down-select on the most suitable pilot control schemes for eVTOL and powered-lift aircraft. The investigation examines three main areas: (1) experimental flight test performance, (2) flight control analysis, and (3) Human-Machine Interface (HMI) factors. Experiments were conducted to evaluate how various inceptor control schemes were perceived by people of various experience levels, ranging from manned aviation pilots with experience in flying F-16 jets, AH-64D helicopters and high-performance turboprop trainers, to unmanned aviation pilots of various backgrounds, such as with remote control (RC) rotorcraft and RC fixed-wing aircraft, and finally to participants with zero experience with either of these. In this experimental surveying study, all participants were briefed on a standardized mission profile and tasked to fly a VTOL drone and a computer based flight simulator using various flight control schemes. Videos were recorded for each test and reviewed for in-depth flight performance and controls scoring and analysis. At the end, feedback on key Human Machine Interface (HMI) factors for each flight control method is obtained. These results in totality provided insights, strengths and weaknesses for each flight control scheme. Upon identification of the most optimal control methodology, a novel energy-based control method to unify both multirotor drone and fixed wing aircraft control logics was developed, future testing will involve incorporating the 3+1 control inceptor scheme with the energy-based control method for further testing and optimization in a simulation environment. The goal of this study is providing a design framework to help eVTOL and powered-lift aircraft designers optimize their pilot control methodology; to become more instinctive, easier to operate, safer and more cost-effective to train new eVTOL and powered-lift pilots and operators.
The emergence of electric Vertical Takeoff and Landing (eVTOL) air vehicles is transforming how people and freight are moved in short distances. This transformation has a profound impact on surrounding infrastructure necessary to provide Aircraft On Ground support for eVTOLs. The hover capabilities of eVTOLs have similar operating characteristics within terminal and uncontrolled airspace. However, the need to conserve battery energy via rapid approaches and departures affects terminal airspace management. To attract eVTOL operators, existing airports, landing zones, and vertiports are modifying their infrastructure to include fixed electric charging stations, additional taxiways, upgraded fire suppression systems, separate hangers, and capable MRO facilities. Augusta Regional Airport (KAGS) is the base airport for the annual Masters Golf Tournament which experiences five times the normal airport traffic and some 40,000 commuting patrons. eVTOLs can offset land traffic issues associated with commuters and supplies. Since KAGS is centroid to 32,000 square miles of territory void of major highways, basing eVTOLs can offer expedited transit services for people and goods which will have a profound impact on the economic viability and quality of life in the area.
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