Higher Level Design Methods Applied to the Conceptual Design of an MALE UAV

The structured design methods such as Quality Function Deployment (QFD), Morphological Matrix, Functional Flow Block Diagrams, and Pugh’s concept generation and selection methods have gained prominence in the product design community as means to develop better products. The current application of these design methods is often limited, because the decisions typically rely on experience, intuition, or at best, on a few simplified calculations and hand-drawn sketches rather than higher-fidelity computations or analysis using Computer Aided Design and Engineering (CAD/CAE) tools. As a result, the choices made or design concepts selected are viewed with skepticism and are not free from the biases and unsupported choices. To reduce this lack of confidence and capitalize on the strengths of the design methods, this paper describes work undertaken to add quantitative analysis to these methods. MS Excel Tables coupled to high level CAD, CAE and Computer Aided Manufacturing (CAM) tools have enabled integration of several aircraft design disciplines earlier in the design process. Aircraft geometry is parametrically defined in Excel coupled to CATIA V5, so the designer only has to enter geometry parameters into a spreadsheet. These tables are further coupled to CAE tools to perform aerodynamics and structural analysis. This approach provides the ability to generate and regenerate a wide variety of design concepts in CAD using CATIA V5. The ability to generate and analyze a wide variety of designs supports the application of Pugh’s method of Controlled Convergence where new concepts are generated based on the evaluation of the first set of candidates. This process is iterated until the best concept is selected. CAD modeling of various wing planforms including swept, tapered, with and without dihedral, joined and BWB planforms, helps in answering several of the questions when discerning which concept best fulfills the mission. Weight and mass calculations, planform area, total area, volume, and material type are among many critical parameters that the CAD modeling can provide with increased accuracy over traditional sketch and empirical formula approaches. The remaining decisions are supported by using high fidelity tools for the respective design disciplines. The approach is applied to the design of a wing for a Medium Altitude Long Endurance (MALE) UAV.