N.A.C.A. Section Clark Y Airfoil coordinates since 1928: Stations, Upper, Lower, per cent per cent per cent chord chord chord 0 3.50 3.50 1.25 5.45 1.93 2.5 6.50 1.47 5 7.90 0.93 7.5 8.85 0.63 10 9.60 0.42 15 10.69 0.15 20 11.36 0.03 30 11.70 0.00 40 11.40 0.00 50 10.52 0.00 60 9.15 0.00 70 7.35 0.00 80 5.22 0.00 90 2.80 0.00 95 1.49 0.00 100 0.12 0.00 Source: WEICK, Fred E.; BAMBER, Millard J.: "Wind Tunnel Tests of A Clark Y Wing with A Narrow Auxiliray Airfoil in Different Positions", NACA Report No. 428, Langley Memorial Aeronautical Laboratory, Washington, USA, 23, February 1932. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091502.pdf SHOEMAKER, James M.: "Air Force Tests of Sperry Messenger Model With Six Sets of Wings", NACA Report No. 269, Langley Memorial Aeronautical Laboratory, Washington, USA, 1928. http://naca.central.cranfield.ac.uk/reports/1928/naca-report-269.pdf N.A.C.A. Section Clark Y Airfoil coordinates 1927: Per cent of chord Upper Lower 0 3.58 3.62 1.25 5.38 1.86 2.5 6.43 1.42 5 7.83 0.91 7.5 8.79 0.59 10 9.56 0.39 15 10.63 0.12 20 11.32 0.01 30 11.68 0.00 40 11.37 0.00 50 10.49 0.00 60 9.13 0.00 70 7.34 0.00 80 5.21 0.00 90 2.79 0.00 95 1.50 0.00 100 0.12 0.00 Source: MUNK, Max M.; MILLER, Elton W.: "The Aerodynamic Characteristics of Seven Frequently Used Wing Sections at Full Reynolds Number", NACA Report No. 233, Langley Memorial Aeronautical Laboratory, Washington, USA, 1927. http://naca.central.cranfield.ac.uk/reports/1927/naca-report-233.pdf