Today, product design has experienced fundamental changes. design criteria have changed from focusing on product performance to sustainable criteria. This has increased the contrast between traditional and new requirements and consequently increases the design complexity. In this regard, traditional methods are incapable of solving the problems of product design. Therefore, many efforts have been made to solve these challenges to improve the design process. As a result of these efforts, various design methodologies such as multidisciplinary design optimization and knowledge-based engineering were developed. These approaches could support the evolutionary improvement of current product designs or the study of the novel complex product or could reduce the coupling between various FRs and design parameters (DPs). In this article, the authors discuss the effect of using the Axiomatic design approach in the Aircraft conceptual design process. The results obtained in this study indicate the high efficiency of this method in reducing the coupling between the FRs defined for the Aircraft, as well as in reducing repetitive activities, thus optimizing the time and cost of the Aircraft design process.

In this paper, the methodology of Aircraft air distribution system has been analyzed theoretically and experimentally. To achieve that, ducting pressure loss and air flow throw gaspers calculation has been done for cabin ducts according to the exact location of individual air distribution system in the cabin. The length of gasper air flow was compared with the distance between gasper outlet and passenger seats and the velocity of the gaspers has been measured with velocity gage on the mockup. Finally design results show a good agreement between air flow throw gaspers and gasper to passenger distance that makes comfortable air feeling conditions. Also the experimental analysis on the mockup validates the results of outlet velocity of gaspers and perforations calculation. Therefore, the validity and feasibility of the design methodology of installation gasper system to a cabin air distribution system for least modifications, suitable location and efficient air flow throw gaspers is confirmed.

The feasibility of using a stand alone Fluidic Thrust- Vectoring (FTV) system for the purpose of longitudinal trim of an unmanned aerial vehicle is the focus of the research presented in this paper. Since the fluidic thrust vectoring requires high pressure secondary air to deflect the engine exhaust gases, this research also provides an analytical toolset for the preliminary sizing of a suitable secondary air supply. The study is based on a conceptual model of a Vertical Take-Off and Landing (VTOL) Tail-sitter type unmanned aerial vehicle in three common phases of flight named as Hovering, Transition and Cruise. A relationship is finally presented between the thrust-vectoring angle and the required secondary mass flow rate.It is found that, just by use of FTV system the Aircraft trim is possible. In addition, the mathematical model developed in this study can be used as a preliminary tool for overall performance evaluation of such a conceptual Aircraft, especially for sensitivity analysis of thrust-vectoring control and finding the optimum values of the parameters like centre of gravity and engine location.