A Multidisciplinary Possibilistic Approach to Light Aircraft Conceptual Design

The conceptual design of light aircraft is typically carried out by using simplified analysis methods and empirical equations. In the conceptual design stage, mass, center-of-gravity (CG) calculations, and drag estimation are usually performed by using statistical equations derived from historical design databases. Constraints including velocity, range, and endurance are highly sensitive to the mass and drag predictions. Constraints including stability and handling qualities are sensitive to the predicted CG location. However, the estimates of these quantities change as the design develops in later stages of the design process. Detailed structural design and aerodynamics analysis is typically carried out later in the design process once a conceptual design has been established. If significant discrepancies are uncovered, design constraints may be found to fail, requiring time consuming design revisions. This paper outlines an approach that implements a multidisciplinary optimization framework using possibility theory to perform light aircraft conceptual design optimization in order to produce results that are more conservative, but more trustworthy than conventional optimization approaches.