Engineering methods on the SACCON configuration - Some design considerations

It is very useful to have fast and reliable engineering tools that can predict the ying and handling qualities of an aircraft, certainly at the early conceptual design stage of a project, but also later for con gurationdesign changes or ight-test planning and analysis. The basis for such predictions involves the coupling of the aerodynamic characteristics, i.e. the forces, moments, and static & dynamic stability derivatives, with the dynamical behavior of the airframe. It is the task of the stability & control analysis (S&C) to assess the ying and handling qualities. Various computational methods to produce the aerodynamic characteristics are used in the S&C analysis. The highestdelity model is the numerical solution of the Navier-Stokes equations. Engineering prediction methods are simpli cations of this model, and can range from empirical or handbook methods like DATCOM, to physics-based linear potentialow models, and to Euler-equation solvers for more realistic inviscid ow. This paper looks at three engineering models. The rst is the Nangia-Aero Panel method based on a panel method enhanced with models for leadingedge vortex ow separation and eventual vortex breakdown. The second is the SHAMAN code based on a vortex-lattice solver with an advanced array of empirical models to enhances its realism. The third one is the CEASIOM framework tool that integrates discipline-speci c tools for aircraft conceptual design. The philosophy underlying CEASIOM’s aerodynamic model di ers from that of the other two methods. Instead of adopting just the potentialow model enhanced with highly-re ned empiricism, CEASIOM uses adaptivedelity CFD, ranging from DATCOM at the low end, via a vortex-lattice method and a panel method to an Euler solver. The choice depends on how much realism is needed to capture the inviscid ow physics at hand, with only secondary reliance on empirical modeling to enhance that realism further. At the high end a RANS solver completes the span in delity.