Air Taxi Research Articles

Effect of Coordination on Transient Response of a Hybrid Electric Propulsion System

Thanks to its typical limited speeds and altitudes, Urban Air Mobility represents an interesting application for electric and hybrid-electric power systems. In addition, short-range requirements are compatible with the limited performance of today’s batteries, conversely to their current inapplicability for commercial aviation purposes. For the present study, a parallel Hybrid Electric Propulsion System for a coaxial-rotor Air Taxi has been implemented in Simulink and tested on four different sets of operating conditions, with a transient signal as input for the Power Lever Angle command. The goal of this investigation is to analyze the transient behavior of the hybrid-electric propulsion system in question, to underline the role of electric motors in assisting thermal engine during transients, and, in particular, focuses on the benefits deriving from the adoption of a coordination block which adapts torque split between the two power sources on the basis of actual engine response.

Factors Affecting Demand Consolidation in Urban Air Taxi Operation

Urban air taxi (UAT) is envisioned as a point-to-point, (nearly) on-demand, and per-seat operation of passenger-carrying urban air mobility (UAM) in its mature state. A high flight load factor has been identified as one of the influential components in the successful operation of UAT. However, the uncertainties in demand, aircraft technology, and concept of operations have raised doubts about the viability of UAT. This study examines the impacts of exogenous parameters, such as demand intensity, demand spread, and ground speed, in addition to design parameters, including aerial speed, maximum acceptable delay, and reservations on average load factor and rate of rejected requests. The dynamic and stochastic problem of UAT fleet operation is studied by implementing a dynamic framework that aims to provide a solution to the problem via a discrete-event simulation. The results highlight the significance of demand spread, ground speed, and maximum acceptable delay in demand consolidation. Therefore, to ensure a high aircraft load factor, the UAT operator should specify the maximum acceptable delay and reservation time window given the demand pattern and ground-based transportation in the network.

Computation of gust induced responses of an air taxi by using Navier-Stokes equations

An air taxi's flight in a gust environment is simulated by using the Navier-Stokes equations time-accurately coupled with structural equations of motion. Gusts are numerically simulated using oscillating vanes similar to a wind tunnel experiment. The configuration is modeled using overset grid topology. Computational results of gust modeling are validated with wind tunnel testing. Aerodynamic responses are validated with the linear theory. Gust-induced structural responses are simulated for a Lift+Cruise air taxi with eight lifting propellers and two pushing propellers. The present work extends the capabilities of the current Navier-Stokes solvers to design urban air taxi configurations for gust environments.

Criteria prioritization for investment policies in General Aviation aerodromes

AbstractDue to the significant proportion of General Aviation (GA) in aircraft fleets and the high number of aerodromes in various countries, establishing investment criteria for aeronautical infrastructure necessitates the formulation of public policies regarding aviation. The literature dealing with the prioritization of airfields in receiving investments commonly uses commercial aviation data, such as the movement of passengers and aircraft at airports. As this kind of measure is not usually recorded in GA, such as the movement of air taxis, agricultural aviation, and instructional flights, the main gap covered by this study is to use variables that are feasible for GA. Adopting Brazil as a case study due to its substantial quantity of aircraft and aerodromes, this study’s georeferenced analysis considered 574 public aerodromes, 4,899 cities, and 4,550 towns distributed throughout the country, totaling 9,449 locations. To prioritize GA aerodromes, multi‐criteria decision‐making was used to prioritize 380 aerodromes with exclusive GA operations. The results indicate that regional location is the main concern in the construction of new aerodromes for GA, to prioritize better spatial coverage within the national territory. Furthermore, the study proposes a simplified mathematical model for public managers to use when formulating public policies to prioritize already existing aerodromes to increase investments and estimate maximum values to invest in these aerodromes. Different variables can be incorporated into the model according to the particularities of each country when formulating public aviation policies.

A methodology to integrate reliability into the conceptual design of safety-critical multirotor unmanned aerial vehicles

This article introduces a new conceptual design methodology to evaluate and explore underactuated electric multirotor unmanned aerial vehicle (UAV) designs for safety-critical applications. A case study focusing on medical transport in an urban environment demonstrates the methodology's effectiveness. The current state of the art does not provide conceptual design methodologies that integrate reliability considerations for multirotor UAVs. The proposed methodology addresses this gap by developing systematic reliability calculation and introducing sizing based on failure cases. For this purpose, controllability and reliability analysis methods are developed and linked to an analytical sizing methodology. The controllability analysis is based on the available control authority index adapted for failure case assessment and reliability analysis. The link between the controllability analysis and the sizing methodology is achieved by introducing failure case sizing factors. The sizing relies on a modern analytical database-free methodology with multidisciplinary design optimization for design customization and computational efficiency. This methodology is developed with new design models to cover failure cases in forward flights. When applied to the case study, the methodology efficiently evaluates and compares five concepts and indicates that only two comply with both the safety and reliability requirements and mission specifications (payload and range). More specifically, the methodology shows the major impact of reliability considerations on the case study with sizing factors that almost double or triple the required rotor thrusts depending on the design. This methodology is applicable to challenging future multirotor UAV applications that require to demonstrate high safety levels and redundancies, such as urban air taxis, flying ambulances, and search and rescue and medical equipment transport.

Reducing Hydrogen Boil-Off Losses during Fuelling by Pre-Cooling Cryogenic Tank

Boil-off losses occur when gaseous hydrogen has to be released from a cryogenic tank due to liquid hydrogen evaporating. These are a substantial drawback for all areas in which liquid hydrogen is discussed as a potential fuel to limit the climate impact. Especially boil-off losses during fuelling are one of the most significant source of losses along the liquid hydrogen pathway. To analyse and minimize such losses, simulations of the filling process are performed with the simulation tool “EcoSimPro”. The simulations are validated with an analytical solution. The results show that boil-off losses can be significantly reduced by pre-cooling the cryogenic tank with liquid nitrogen. This method is most effective for relatively small tanks that could be used e.g., in small air crafts or air taxis.

Güvenli kara sistemi mimari tasarimi motor arizalarini dikkate alarak çok rotorlu mimari tasarimi

There is growing interest to use drones for application like delivery services, air taxi, surveillance, and inspection to reduce operational time and cost and increase the performance and functionalities. However, there are some risks related to using this technology one of them is the hazard to the humans and assets in the case of an emergency scenario like motor failure. The current technologies suggest to land as soon as possible in such these scenarios, however finding and selecting a suitable landing area considering the capabilities of the faulty drone and controlling the drone towards the selected point is a problem which requires provisions during the design process of the drone. The situations get more complex considering that the vehicle should be able to adopt itself by its time varying environment. In this paper the system approach is used to break the safety requirements to functional and physical requirements and based on these requirement analyses, the functional and physical architectures of the drone are designed. The proposed design suggests that the drones aggregate their perception about the environment to maximize the safety of people and assets through a special databank called potential landmark databank.

Airframe Design Optimization and Simulation of a Flying Car for Medical Emergencies

In terms of future transportation, flying cars are envisioned not only as air taxis but also as air ambulances. Flying cars such as urban air mobility vehicles, passenger drones, and electrical vertical take-off and landing (eVTOL) aircrafts have the potential to relieve seriously congested ground traffic in cities via direct point-to-point air movements. To date, conventional research in which the airframe of a flying car is optimized for use in medical emergencies has not identified a sustainable solution. The purpose of this study is to verify the technical applicability of a flying car for use in medical emergencies. The weighted sum method is used to optimize the design of multi-rotor, vectored-thrust (tilt-rotor), and lift + cruise types of flying cars. A simulation scenario that considers cruising speed and flight height is conducted based on an analysis of stakeholder interviews with a pilot, an in-flight doctor, and an operating company. To optimize the parameters of a flying car airframe, four objective functions, namely the energy required for a round trip, noise value from rotors, downwash speed from rotors, and landing area size, are chosen because the results of a requirement analysis revealed that they were significant for the sustainability of the flying car system. The results of the simulation reveal that the required battery energy densities for all three types exceed the current lithium-ion battery capacities. Therefore, an upgrade in battery capacity is critical for the realization of a flying car. Although the noise level is found to be less than that of a conventional helicopter, it is necessary to develop a rotor to decrease noise levels for environmental reasons. Finally, both the downwash speed and landing area of a flying car are estimated to be less than those of a conventional helicopter, making it possible for the flying car to land in tight spaces.

Shake Maker

The first ground vibration tests of electric aircraft such as air taxis are revealing the complex challenges that exit around flutter

Flight Scheduling and Fleet Sizing for an Airport Shuttle Air Taxi Service

A multicommodity network flow framework for optimal flight scheduling for an envisioned airport shuttle air taxi service is presented. The framework includes a trip generation model that simulates requests from individuals who travel to and from the airport and are willing to pay for the travel time savings associated with an airport shuttle air taxi service. The framework can be used to determine the fleet size required to satisfy a given user demand and to assess how an operator’s profitability can be influenced by multiple factors, including the population density and income distribution in a metropolitan area, fleet size, ticket price, and air taxi operating costs. The results for an example business airport shuttle service to and from Atlanta Hartsfield Jackson International Airport suggest that a viable business case is possible using electric vertical take-off and landing aircraft. For example, the results for this Atlanta case study indicate that it is possible to have profitable business use case with positive cash flow with a four-seat aircraft with a 60-mile design range and a 150 mph cruise speed using a fleet size of five aircraft at a price point of $5 per passenger-mile during near-term small-scale operations.

Highly iterative concept development for requirement-compliant air taxis

The increasing demand for individual mobility worldwide is leading to the development of new forms of mobility. Individual air mobility (e.g., air taxis) could be one innovative approach to meet this increasing demand. To successfully realise such innovative approaches, interested companies must know the technical, economic, and ecological requirements of all relevant stakeholders and integrate them in their air taxi developments. Based on these diverse requirements, a resilient air taxi concept must first be created that describes the essential characteristics of future air taxis and enables a well-founded assessment. However, in practice, it is often difficult for companies to outline such a concept and then develop it consistently and highly iteratively. To face this challenge, a process has been set up which creates a deep link between the requirements and concept development phase to assure the development of requirement-compliant air taxis in an agile manner. The process is divided into two parts. The first part connects the market analysis, requirements definition and concept creation, thus linking the requirements and concept development phase. It is based on a double diamond model consisting of two phases. In contrast, the second part is focusing on the pre-development until the end of the concept development phase by adapting the SCRUM methodology to derive a sound air taxi concept. Both parts are executed in a highly iterative manner to reflect the significant amount of uncertainty at this early process stages.

Energy consumption and environmental impact of Urban Air mobility

Urban Air Mobility (UAM) is a recent concept proposed for solving urban mobility problems, such as urban traffic pollution, congestion, and noises. The goal of this investigation is to develop a backward model for an electric aerial taxi in order to estimate the electric consumption and the indirect emissions of carbon dioxide in a specified mission. The model takes as input the time histories of speed and altitude and estimates the power at the rotor shaft during the mission with a quasi-static approach. The shaft power is used as input for the electric drive where the motor is modelled with an efficiency map and a transfer function while an equivalent circuit model which includes aging effects is used for the battery. The emissions of CO2 are calculated as a function of the Greenhouse emission intensity and compared with that of a hybrid electric taxi performing the same mission with the same payload. A plug-in Toyota Prius modelled through the software ADVISOR is considered for the comparison. The results show that the air taxi behaves better than the road taxi not only in terms of trip time but also from the environmental point of view if the charging of the battery is performed with the emission intensity factory expected to be reached in Europe in 2025.

Vertiport and air taxi features valued by consumers in the United States and India

BackgroundUrban Air Mobility aircraft (UAMs) have been proposed as a fast, efficient way to move people through congested areas. However, while nearly everyone is familiar with commercial airline operations and assume they are safe, UAMs remain a nascent product that have yet to be widely understood by the public. In this study, we identify factors that might affect the flying public’s choice of vertiports and air taxis. MethodsWe sampled 1125 people from the United States and India. In stage 1, participants were asked to identify concerns regarding vertiports and UAMs. In stage 2, they were asked to rate the importance of each concern. ResultsWe found that potential passengers are primarily concerned about UAM safety and security, both for vertiports and UAMs. Convenience items also appeared, but were generally rated as less important than safety and security items. DiscussionFuture vertiport and air taxi developers will benefit from a better understanding of potential passengers’ concerns. Messaging should include education about how safety and security is ensured for both UAMs and vertiports.

A Methodology for the Comparative Analysis of Hybrid Electric and All-Electric Power Systems for Urban Air Mobility

The present investigation addresses the topic of Urban Air Mobility with particular reference to the air-taxi service with electrified power systems. A new and detailed methodology is proposed for the simplified design and energy analysis of conventional, hybrid-electric, and full-electric power systems for this application. The original contributions to the scientific literature on UAM are the detailed modeling approach, the evaluation of CO2 emissions with a Well-to-Wing approach as a function of the electricity Emission Intensity factor, and the comparison with road vehicles performing the same route in different driving conditions. The comparison demonstrates the advantages of a full electric air-taxi with today’s technology versus a hybrid-electric road taxi, especially in cases involving low emission intensity and unfavorable driving conditions (congested traffic, aggressive driving style, and high circuity factor values). In the case of 2035 technology, the comparison with a referenced fully electric road vehicle is detrimental to the air taxi but the values of Well-to-Wheel/Wing CO2 with the expected Emission Intensity of 90 g/kWe for the European Union are still quite low (67 g/km). The investigation also quantifies the negative effect of battery aging on the consumption of the air taxi and on the number of consecutive flights that can be performed without fully charging the battery.

Design of Secure Handover Authentication Scheme for Urban Air Mobility Environments

Urban air mobility (UAM) is a future air transportation system to solve the air pollution and movement efficiency problems of the traditional mobility system. In UAM environments, unmanned aerial vehicles (UAV) are used to transport passengers and goods providing various convenient services such as package delivery, air bus, and air taxi. However, UAVs communicate with ground infrastructures through open channels that can be exposed to various security attacks. Therefore, a secure mutual authentication scheme is necessary for UAM environments. Moreover, a handover authentication is also necessary to ensure seamless communication when the service location is changed. In this paper, we design a secure and efficient handover authentication scheme for UAM environments considering various security vulnerabilities and efficiency using elliptic curve cryptography (ECC). We utilize informal security analysis, Real-or-Random (RoR), Burrows–Abadi–Needham (BAN) logic, and Automated Validation of Internet Security Protocols and Applications (AVISPA) to prove the security of the proposed scheme. Furthermore, we compare the computation and communication cost comparisons of the proposed scheme with the other related schemes. The results show that the proposed scheme is secure and efficient for UAM environments.

Air Taxis: A Technological Breakthrough to Beat the Traffic Woes

Air Taxis: A Technological Breakthrough to Beat the Traffic Woes

The public acceptance of drones – Challenges for advanced aerial mobility (AAM)

In recent years, civil drones have become increasingly present in the media and in everyday life. However, public acceptance of drones still seems limited, with acceptance rates usually ranging around 50%.This contribution reports recent findings about the acceptance of civilian drones. Several factors influencing the public attitude towards drones are described here, such as the acceptance of certain drone applications and concerns about civil drones in general, with special consideration given to concerns about noise. Moreover, an effect of NIMBYism is confirmed, as even residents who envision using drones for the delivery of parcels or as air taxis frequently report that they would not agree to flights over their own homes. Special attention is paid to the problem of increasing noise annoyance among residents near airports and its implications for the upscaling of drone operations, as well as potential countermeasures.Finally, the need for regulation is discussed, as well as potential measures to meet certain challenges of advanced aerial mobility. Providing consistent and transparent information about drones by stakeholders is seen as basic measure to increase acceptance. Besides defining aspects like topographical conditions, urban areas and time restrictions by regulation, providing residents with tools for participatory noise sensing can also be a viable measure to increase public support for advanced air mobility.

Unmanned Aerial Vehicle Propagation Channel over Vegetation and Lake Areas: First- and Second-Order Statistical Analysis.

The use of unmanned aerial vehicles (UAV) to provide services such as the Internet, goods delivery, and air taxis has become a reality in recent years. The use of these aircraft requires a secure communication between the control station and the UAV, which demands the characterization of the communication channel. This paper aims to present a measurement setup using an unmanned aircraft to acquire data for the characterization of the radio frequency channel in a propagation environment with particular vegetation (Caatinga) and a lake. This paper presents the following contributions: identification of the communication channel model that best describes the characteristics of communication; characterization of the effects of large-scale fading, such as path loss and log-normal shadowing; characterization of small-scale fading (multipath and Doppler); and estimation of the aircraft speed from the identified Doppler frequency.

Scalable Vertiport Hub Location Selection for Air Taxi Operations in a Metropolitan Region

On-demand air mobility services, often called air taxis, are on the way to revolutionize our urban/regional transportation sector by lifting transportation to the third dimension and thus possibly contribute to solving the congestion-induced transportation deadlock many metropolitan regions face today. Although existing research mainly focuses on the design of efficient vehicles and specifically battery technology, in the near future, a new question will arise: Where to locate the vertiports/landing pads for such air taxis? In this study, we propose a vertiport location selection problem. In contrast to existing studies, we allow the demand to be distributed over the whole metropolitan area, modeled as a grid, and exclude certain grid cells from becoming hubs, for example, because of safety/geographical constraints. The combination of these two contributions makes the problem intriguingly difficult to solve with standard solution techniques. We propose a novel variable neighborhood search heuristic, which is able to solve 12 × 12 grid instances within a few seconds of computation time and zero gaps in our experiments, whereas CPLEX needs up to 10 hours. We believe that our study contributes toward the scalable selection of vertiport locations for air taxis. Summary of Contribution: The increasing interest in opening the third dimension, that is, altitude, to transportation inside metropolitan regions raises new research challenges. Existing research mainly focuses on the design of efficient vehicles and control problems. In the near future, however, the actual operation of air taxis will lead to new set of operations research problems for so-called air taxi operations. Our contribution focuses on the optimization of vertiports for air taxi operations in a metropolitan region. We choose to model the problem over a grid-like demand structure, with a novel side constraint: selected grid cells are unavailable as hubs, for example, because of environmental, technical, cultural, or other reasons. This makes our model a special case in between the two traditional models: discrete location and continuous location. Our model is inherently difficult to solve for exact methods; for instance, solving a grid of 12 × 12 grid cells needs more than 10 hours with CPLEX, when modeled as a discrete location problem. We show that a straightforward application of existing neighborhood search heuristics is not suitable to solve this problem well. Therefore, we design an own variant of mixed variable neighborhood search, which consists of novel local search steps, tailored toward our grid structure. Our evaluation shows that by using our novel heuristic, almost all instances can be solved toward optimality.

Comparative analysis of the structure of passenger transportation in Russia

Passenger transport of the country has a significant impact on the level of its economic development, providing the connection of the population with objects of industrial, social, cultural and household purposes.In Russia, intercity passenger transportation by public transport is mainly represented by bus, rail, aviation (aircraft) and water (domestic). The article analyzes the dynamics of passenger transportation and passenger turnover of public transport for the period from 2015 to 2020, presents a calculation of the number of flights performed by bus, rail, air (aircraft) and water (domestic) transport, identifies the reasons for the lack of development of passenger transportation and suggests solutions.It is established that inland water transport is currently undergoing decline and state intervention is necessary for their development. Also, during the period under review, there is a decrease in the popularity of buses and a preference for private transport to public, it is necessary to improve the quality of transportation. The indicators of air and rail transport have positive dynamics, but they also require growth. The development of air transport in Russia can be carried out by the introduction of new services, for example, air taxi, rail-transport in the field of urban and suburban communications, the construction of new high - speed highways. In 2020, due to the announcement of restrictions on movement and quarantine measures, there is a sharp decline in indicators for all types of transport.The materials can be used to analyze and improve the work of the country's passenger complex.