Search results

SINCE man first aspired to fly the desire to take‐off and land vertically and to hover in flight has always presented a challenge to the engineer. To date only the rotary wing aircraft has achieved these aims in service but their shortcomings in terms of speed, range and economy have encouraged engineers to search for more elegant ways of achieving vertical flight.

THE aircraft gas turbine is intriguing in that there were early attempts at its development not only by the established aero engine companies and research establishments in many countries, but also by manufacturers of marine and industrial turbines and — most successfully — by individuals. The aero engine companies failed because in virtually every instance they attempted to produce a power unit of comparable or lower specific fuel consumption to the traditional piston engine. This led to unduly complex designs involving unattainably high component efficiencies and turbine temperatures at far too early a stage in the development of the new prime mover.

Recent advancements in electrified transportation have been necessitated by the need to reduce environmentally harmful emissions. Accordingly, several aviation organisations and governments have introduced stringent emission reduction targets for 2050. One of the most promising technologies proposed for achieving these targets is turboelectric distributed propulsion (TeDP). The objective of this study was to explore and identify key indicators for enhancing the applicability of TeDP in air transportation.

An enhancement valuation method was proposed to overcome the challenges associated with TeDP in terms of technological, economic and environmental impacts. The result indicators (RIs) were determined; the associated performance indicators (PIs) were analysed and the key RIs and PIs for TeDP were identified. Quantitative measurements were acquired from a simulated TeDP case study model to estimate the established key PIs.

It was determined that real-world TeDP efficiency could be enhanced by up to 8% by optimising the identified key PIs.

This study is the first to identify the key PIs of TeDP and to include a techno-economic environmental risk analysis (TERA) based on the identified key PIs. The findings could guide developers and researchers towards potential focus areas to realise the adoption of TeDP.

Suggests that the next civil supersonic passenger aircraft project will pose a number of challenges. The propulsion system for this aircraft will have to achieve economic operation for both supersonic and subsonic cruise modes. In addition, the current and intended noise and pollutant emissions legislation will have to be met. Suggests that, while there are a number of proposed engines for the next generation civil supersonic aircraft, they all exhibit difficulties in meeting the compromises inherent in the engine duty. Offers a novel solution based on a unique design. Discusses the underlying issues and presents the design based on retractable fans driven by a single stage double pass tip turbine.

Process of building and then implementation of integrated multimodal, passenger-centred and predominantly sustainable transport system will require a specific effort to be input in preparation, especially if it covers new entrants like passenger Urban Air Mobility. This paper aims to address the first step which is the identification of barriers to be overcome to turn the concept into reality.

Comparison of the current state-of-the-art in transportation, Information and Communication Technologies as well as other city planning domains to the forecasted ecosystem, described in the form of scenarios where base for definition of necessary actions, challenges as well as potential barriers and obstacles were identified and thoroughly specified.

Barriers grouped in five categories: policy, digitalisation, transportation technologies, integration technologies and passengers’ needs allow for formulation of the relevant roadmaps defining optimal development path towards fully integrated multimodal, passenger-centred and sustainable transport system.

Conclusions can be a starting point in studies towards development of roadmap for implementation of truly integrated municipal transport system both sharing the resources as well as high-level objectives.

Conclusions can be exploited in various areas starting from preparation of strategies in cities aspirating to be smart, through definition of technology development priorities by relevant agencies ending with industry actors looking for better trimming their business.

The identified barriers as derived from detailed investigation enable deep insight into the total transport system vision in which Urban Air Mobility integrated within urban mobility ecosystem is considered as game-changing factor having large potential to contribute to both making cities smart and sustainable.

Conventionally, shipping companies have invested in large ships to achieve economies of scale. More recently, high speed ships have been proposed as a means of achieving timely service for customers and improving shipping performance. Yet another solution offered here is to boost the cargo handling speed at port allowing for a higher number of annual round trips. Both the cost efficiency and timeliness of shipping service can be improved. The economic trade‐offs between the investments in cargo handling and ship propulsion technologies are formally analysed by taking the round trip frequency as the key to performance. The theoretical analyses as well as the practical cases studied indicate that investments in cargo handling technology, such as automation of container terminal operations and hatchless self‐loading ships, have indeed considerable profit‐making potential for shipping companies. Other technology investment opportunities appear less promising: ship propulsion due to energy consumption and environmental concerns; and larger ships due to low customer responsiveness and risks of low capital productivity.

Novel aircraft propulsion configurations require a greater integration of the propulsive system with the airframe. As a consequence of the closer integration of the propulsive system, higher levels of flow distortion at the fan face are expected. This distortion will propagate through the fan and penalize the system performance. This will also modify the exhaust design requirements. This paper aims to propose a methodology for the aerodynamic optimization of the exhaust for novel embedded propulsive systems. To model the distortion transfer, a low order throughflow fan model is included.

As the case study a 2D axisymmetric aft-mounted annular boundary layer ingestion (BLI) propulsor is used. An automated computational fluid dynamics approach is applied with a parametric definition of the design space. A throughflow body force model for the fan is implemented and validated for 2D axisymmetric and 3D flows. A multi-objective optimization based on evolutionary algorithms is used for the exhaust design.

By the application of the optimization methodology, a maximum benefit of approximately 0.32% of the total aircraft required thrust was observed by the application of compact exhaust designs. Furthermore, for the embedded system, it is observed that the design of the compact exhaust and the nacelle afterbody have a considerable impact on the aerodynamic performance.

This paper presents a novel approach for the exhaust design of embedded propulsive systems in novel aircraft configurations. To the best of the authors’ knowledge, this is the first detailed optimization of the exhaust system on an annular aft-mounted BLI propulsor.

The purpose of this article is to provide an outline of the challenges of thermal management for more-electric, hybrid-electric and all-electric aircraft, and to notionally discuss potential solutions.

A code algorithm was developed to facilitate architecture-level analysis of the coupled relationship between the propulsion system, the thermal management system, and the takeoff gross weight of aircraft with advanced propulsion systems.

A variety of coupled relationships between the propulsion and thermal management systems are identified, and their impact on the conceptual design choices for electric aircraft are discussed qualitatively.

This conceptual article merely illuminates some driving factors associated with thermal management. The software is still in its adolescence and is experiencing ongoing development.

Thermal regulation in electric aircraft is shown to be a topic that should be addressed in tandem with propulsion system architecture definition and component selection. High-power electronics are expected to emit an immense amount of heat, and the common avenues of heat dissipation could substantially impact the aircraft’s weight, drag and performance. Conversely, strategic management of this waste heat could support subsystems or even produce additional thrust.

This paper aims to direct the attention of researchers and designers in the field of hybrid- or all-electric aircraft design toward the challenges and potential benefits of thermal management.

This paper describes a novel conceptual design software and discusses its logic flow and implications.

The Convair B.58 Hustler is a Mach 2, delta‐winged bomber which makes extensive use in its structure of metal bonding adhesives. The entire surface covering of the B.58 is composed of bonded structure with the exception of the elevons and the aft section of the nacelles and pylons. The aluminium bonded structures used are (i) beaded panels in the fuselage and (ii) sandwich panels in the wing. The delta wing is of multi‐spar construction with no chordwise ribs as in conventional wing structure but with chord‐wisc members at elcvon, nacelle and landing gear attachment points. To simplify tooling, construction and assembly all wing sandwich panels were made of one consistent overall thickness. This dimension is 0–58 in. and all skin thickness changes are accounted for by varying chord thickness. Fuselage surface skins are stiffened by the use of beaded inner skins. Alloys used were the 2024 range. The paper describes the selection and use of the adhesives for bonding and the structural development programme. Construction details and cost are also covered. 52,700 panels have been produced with a scrap rate of only 4 per cent.

NASA and an industrial high‐speed civil transport propulsion team is studying whether to plan a potentially expensive series of flight tests to analyse performance of components critical to the success of supersonic aircraft.