Geometric Functional Specification for a Lifting Airfoil

This paper presents a possible functional geometric specification for a lifting airfoil including the definition of functional tolerance limits (tolerance synthesis) and an associated inspection procedure. The proposed specification scheme is derived from the analogy between the mating of the airfoil with a fluid field and the consolidated example of the mating of a prismatic element in its site. The airfoil thickness is defined as a non-constant size with non-constant tolerances and the airfoil shape is prescribed with a non-constant profile of a line tolerance applied to the median airfoil line. The tolerance synthesis is based on XFLR5 software and Computational Fluid Dynamics (CFD) simulations. The inspection procedure uses the data acquired with a laser probe elaborated in Geomagic Wrap, GOM inspect and MATLAB. The overall process has been applied to a case study allowing to define limits and proposing a set of possible improvements regarding, particularly, the geometric specification of the leading and trailing edges of the airfoil.