Design methodology for aerodynamically scaling of a general aviation aircraft airfoil

This paper discusses the aerodynamic scaling process of a 1/5^th -scale R/C model of the Cessna 182 for the General Aviation Upset and Stall Testing Aircraft Research (GA-USTAR) project. The GA-USTAR project aims to construct a dynamically-scaled model of typical General Aviation aircraft for the purpose of validating flight simulator stall/upset models. Modeling the stall behavior of a scaled aircraft requires aerodynamic scaling to account for changes in the operating Reynolds number. Aerodynamic scaling of the Cessna 182 was accomplished through the design of a new wing airfoil that matched the lift curve slope, maximum lift coefficient, and the moment coefficient of the wing airfoil (NACA 2412) of the full-scale Cessna 182 at stall conditions. To accomplish this, an in-house developed inverse airfoil design tool, PROFOIL, was used to design the VAS1715 airfoil. The VAS1715 airfoil, is 12% thick and has a maximum camber of 5.16%. The VAS1715 airfoil was designed to have the same maximum lift coefficient at a Reynolds number of 230,000 (scaled Cessna 182 stall Re) as the NACA 2412 airfoil at a Reynolds number of 2,700,000 (full-scale Cessna 182 stall Re). Verification of the designed VAS1715 airfoil performance was carried out by performing experimental validation using the University of Illinois at Urbana-Champaign (UIUC) Low Speed Airfoil Testing setup at the UIUC Aerodynamic Research Lab for Reynolds numbers ranging from 200,000 to 450,000. For each of Reynolds numbers tested lift and moment of the VAS1715 airfoil were measured for angles of attacks from −10 to 20 deg to obtain the linear and post-stall range. The drag for each Reynolds number was measured separately using a wake rake from −10 to ∼14 deg (up to stall). Measured experimental VAS1715 airfoil performance data are summarized in this paper together with discussion of the results and its matching with NACA 2412 airfoil (full-scale Cessna 182 wing airfoil) results.