Actually, the wings are wood but much of the fuselage is steel tube and aluminum. Modern materials such as carbon fiber were also used in areas like some of the complex segments of the cowl. The original plans were used to insure the dimensions, shapes, angles of all components were to spec.
BTW, I was in my hanger a couple of weeks ago tinkering with the 9a and heard a distinctive sound--he had taken off from KPRC and did an early turn out over my hanger under full power------nothing like the sound of a big Allison or Merlin.
RV9a/ECiIO360/James Cowl/WW RV200 Prop
Flying since 3/06 and still smiling!!!