Contratos de leasing

The literature review has presented an overview of emerging trends in aircraft technology and the aviation industry. Developmental goals for aviation have set challenging targets with the

2. Literature Review

Figure 2.12: Research phases

aim of establishing a more environmentally sustainable industry. This has necessitated the development of revolutionary new technologies with lower emissions and energy consumption.

Despite constant growth in the industry, profit margins remain low. It is therefore vital to ensure that the aviation industry remains economically sustainable. In a commercial industry, cost is the dominant decision factor. This can be easily demonstrated using the historical case of the propfan engine concepts of the 1980s [14]. The propfan offered an efficiency increase ideal for the then high fuel price market. However, a drop in fuel price reduced the attractiveness of investment in expensive, novel technologies, despite a demonstrable efficiency increase.

Development of propfan engines was subsequently halted, following a lack of interest by airline operators. The reduction in fuel consumption offered by the propfan no longer justified cost of investment in novel technology [78]. Cost is therefore a vital decision factor in the selection of future investment in the aviation industry. This is especially true where risk is high.

The technologies presented in the previous sections are promising from a performance standpoint, but their economic viability is unknown. A wide range of concepts are currently being researched to achieve developmental goals. If it can be assumed that each competing concept is designed for the same performance level, then the only method to differentiate be-tween options is cost. In a profit-oriented industry, decisions cannot be made from an altruistic perspective. As the end goal is for the industry to adopt environmentally friendly technologies, it is vital to ensure that the technologies selected for further development are those that will be financially attractive or profitable. The cost of a concept must be considered at an early stage in order to determine its economic viability and rule out those technologies that may not be attractive. This highlights the necessity for a techno-economic analysis, even when aircraft concepts are at an early development stage. Otherwise, the industry runs the risk of devel-oping technologies that will not be adopted by manufacturers or operators as costs would be prohibitive.

The work scope identifies a number of aspects that must be addressed to develop a techno-economic and environmental risk assessment of a novel aircraft. The previous sections have presented a number of different perspectives on how a techno-economic assessment can be performed. However, two key gaps in research have been identified that this research attempts to address. When dealing with evolutionary technology, cost estimates can be made with rea-sonable accuracy, as there is historical data on which estimates can be based. It is therefore relatively simple to determine whether a new technology is likely to be profitable. For revolution-ary or novel technologies, estimating cost is more difficult and hence it can be challenging to make conclusions regarding an aircraft’s viability without including a large number of assump-tions. It is nevertheless useful to have some way of predicting the viability of a concept in order to ensure financial viability and encourage investment. This is particularly important for revo-lutionary concepts, where the perception of high risk may deter the investment necessary for the technology’s implementation. Another key gap is the need for comparative assessments, including the influence of policy and external economic factors. An aircraft can be optimised for minimum cost or for a certain performance target, however, the concept will fail if a competitor offers a more cost effective option. Techno-economic modelling generally focuses on optimis-ing or assessoptimis-ing a soptimis-ingle aircraft, without comparoptimis-ing its viability to alternatives. The study by Goel and Rich [72] highlighted that a significant operating cost difference between existing and

new technology was an incentive for adoption. Comparative assessments that identify whether there is a significant operating cost difference are therefore a vital aspect of determining a concept’s viability. Similarly, investment cannot be justified if the savings offered by the new technology are not significant. This comparative assessment can be used to view development from the airline customer perspective, in order to identify whether technologies will be attractive investments.

This research addresses the two identified gaps in research and presents a framework for assessing the viability of a novel aircraft concept. The framework used by Nalianda et al. [78] was extended to be applied to novel aircraft. This research presents the application of a comparative framework of assessment that is intended to present a operator’s perspective for the manufacturer on determining whether a concept is economically viable and suitable for investment. The main aim of this research can be summarised as follows:

TO DEVELOP A TECHNO-ECONOMIC METHODOLOGY TO ASSESS,COMPARE,AND SELECT ENVIRONMENTALLY OPTIMISED AIRCRAFT CONCEPTS UTILISING NOVEL TECHNOLOGIES

During the course of the research, a further gap in literature was identified. Modelling pro-cedures were required for boundary layer ingesting propulsion systems as an element of mod-elling a novel aircraft configuration. Previous models published in literature focus on proving the potential benefits of BLI propulsion. These studies therefore focus on design point sizing and performance. As research on aircraft with BLI propulsion progresses, it becomes necessary to develop tools that are able to simulate the performance of such systems at a wide range of operating points. A generic off-design modelling procedure that can be consistently applied to different configurations was therefore required as a component of the research. A workflow and tool for modelling BLI propulsion systems was developed during the course of the research to address this gap in current research. Subsequently, an aircraft performance modelling tool was developed to integrate the BLI propulsion system modelling workflow. The secondary aim of the research may therefore be summarised as follows:

TO DEVELOP A GENERIC WORKFLOW TO DESIGN AND SIMULATE THE PERFORMANCE OF A BOUNDARY LAYER INGESTING PROPULSION SYSTEM AT OFF-DESIGN,SUITABLE FOR USE WITH

AIRCRAFT PERFORMANCE SIMULATION METHODS