The Nealon Equation
 y  =  (A*sin(B*x+C) + D*sin(E*x+F) + G*sin(H*x+I) + J*sin(K*x+L)) *  (M + N*x + O*x^2 + P*x^3 + Q*x^4) * atan(R*x) * atan(S*(BL-x))
 Martin OM / 000
 y = (A*sin(B*x+C)+D*sin(E*x+F)+G*sin(H*x+I)+J*sin(K*x+L))*(M+N*x+O*x^2+P*x^3+Q*x^4)*atan(R*x)*atan(S*(19.35-x))
 Graphed in “Graph”
 Calculated curve
 Body mold is from the Martin Company.  I laid the mold onto a piece of graph paper and drew the outline.  One hundred ninety eight data points later, voilà:
 Martin OM / 000 A -0.06393446 B -0.7410887 C 1.180973 D -1.24886 E 0.3187446 F -0.8305975 G 2.352912 H -0.1870003 I 3.40192 J -0.01303915 K 1.349344 L 4.32767 M 5.228206 N -0.4099881 O -0.000250234 P 0.0007021002 Q 0 R 18.26765 S 18.1965 BL 19.35 A B C D E F G H I J K L M N O P Q R S BL -0.06393446 -0.7410887 1.180973 -1.24886 0.3187446 -0.8305975 2.352912 -0.1870003 3.40192 -0.01303915 1.349344 4.32767 5.228206 -0.4099881 -0.000250234 0.0007021002 0 18.26765 18.1965 19.35 A = -0.06393446 B = -0.7410887 C = 1.180973 D = -1.24886 E = 0.3187446 F = -0.8305975 G = 2.352912 H = -0.1870003 I = 3.40192 J = -0.01303915 K = 1.349344 L  = 4.32767 M = 5.228206 N = -0.4099881 O = -0.000250234 P = 0.0007021002 Q = 0 R = 18.26765 S = 18.1965 BL = 19.35