Flying on wood and fabric: The tree species used for the construction of the Ansaldo A.1 "Balilla" biplane (1918)

The Ansaldo A.1 "Balilla" biplane is of great historical interest, because it illustrates the level of development reached by the Italian aircraft industry during the last stages of World War I. To date, the airplane is kept in its original state, and it has never been restored. The aircraft is essentially made of wood and fabric. Wood in particular has been used in a very skilful way, making the airplane lightweight, yet elastic and resistant. In this work, the entire wooden structure of the aircraft was analysed, and the tree species were microscopically identified. Species belonging to six different genera have been identified. We found spruce in the frame, elm in the wing ribs, walnut in the propeller, alder in various plywood layers, rosewood in the outer layer of the decorative plywood, and pine in the tail rudder. The main structure of the aircraft was made of spruce, most likely a Sitka spruce, which was widely used for aircraft construction. The Ansaldo A.1 "Balilla" biplane is an excellent example of the wise use of wood before the revolution upon the boost in synthetic materials and represents an important historical and cultural heritage.