# set terminal canvas rounded size 600,400 enhanced fsize 10 lw 1.6 fontscale 1 name "airfoil_1" jsdir "." # set output 'airfoil.1.js' set dummy t, y set style increment default set parametric set style data lines set title "NACA6409 Airfoil" set trange [ 0.00000 : 1.00000 ] noreverse nowriteback set xlabel "NACA6409 -- 9% thick, 40% max camber, 6% camber" set xrange [ -0.100000 : 1.10000 ] noreverse nowriteback set x2range [ * : * ] noreverse writeback set yrange [ -0.100000 : 0.700000 ] noreverse nowriteback set y2range [ * : * ] noreverse writeback set zrange [ * : * ] noreverse writeback set cbrange [ * : * ] noreverse writeback set rrange [ * : * ] noreverse writeback bez_d4_i0(x) = (1 - x)**4 bez_d4_i1(x) = 4 * (1 - x)**3 * x bez_d4_i2(x) = 6 * (1 - x)**2 * x**2 bez_d4_i3(x) = 4 * (1 - x)**1 * x**3 bez_d4_i4(x) = x**4 bez_d8_i0(x) = (1 - x)**8 bez_d8_i1(x) = 8 * (1 - x)**7 * x bez_d8_i2(x) = 28 * (1 - x)**6 * x**2 bez_d8_i3(x) = 56 * (1 - x)**5 * x**3 bez_d8_i4(x) = 70 * (1 - x)**4 * x**4 bez_d8_i5(x) = 56 * (1 - x)**3 * x**5 bez_d8_i6(x) = 28 * (1 - x)**2 * x**6 bez_d8_i7(x) = 8 * (1 - x) * x**7 bez_d8_i8(x) = x**8 mean_y(t) = m0 * mm * bez_d4_i0(t) + m1 * mm * bez_d4_i1(t) + m2 * mm * bez_d4_i2(t) + m3 * mm * bez_d4_i3(t) + m4 * mm * bez_d4_i4(t) mean_x(t) = p0 * bez_d4_i0(t) + p1 * bez_d4_i1(t) + p2 * bez_d4_i2(t) + p3 * bez_d4_i3(t) + p4 * bez_d4_i4(t) z_x(x) = x0 * bez_d8_i0(x) + x1 * bez_d8_i1(x) + x2 * bez_d8_i2(x) + x3 * bez_d8_i3(x) + x4 * bez_d8_i4(x) + x5 * bez_d8_i5(x) + x6 * bez_d8_i6(x) + x7 * bez_d8_i7(x) + x8 * bez_d8_i8(x) z_y(x, tk) = y0 * tk * bez_d8_i0(x) + y1 * tk * bez_d8_i1(x) + y2 * tk * bez_d8_i2(x) + y3 * tk * bez_d8_i3(x) + y4 * tk * bez_d8_i4(x) + y5 * tk * bez_d8_i5(x) + y6 * tk * bez_d8_i6(x) + y7 * tk * bez_d8_i7(x) + y8 * tk * bez_d8_i8(x) airfoil_y1(t, thick) = mean_y(z_x(t)) + z_y(t, thick) airfoil_y2(t, thick) = mean_y(z_x(t)) - z_y(t, thick) airfoil_y(t) = mean_y(z_x(t)) airfoil_x(t) = mean_x(z_x(t)) mm = 0.6 thick = 0.09 pp = 0.4 x0 = 0.0 y0 = 0.0 x1 = 0.0 y1 = 0.18556 x2 = 0.03571 y2 = 0.34863 x3 = 0.10714 y3 = 0.48919 x4 = 0.21429 y4 = 0.58214 x5 = 0.35714 y5 = 0.55724 x6 = 0.53571 y6 = 0.44992 x7 = 0.75 y7 = 0.30281 x8 = 1.0 y8 = 0.0105 m0 = 0.0 m1 = 0.1 m2 = 0.1 m3 = 0.1 m4 = 0.0 p0 = 0.0 p1 = 0.2 p2 = 0.4 p3 = 0.7 p4 = 1.0 plot airfoil_x(t), airfoil_y(t) title "mean line" w l lt 2, airfoil_x(t), airfoil_y1(t, thick) title "upper surface" w l lt 1, airfoil_x(t), airfoil_y2(t, thick) title "lower surface" w l lt 1