Though faster and more advanced than the RAF's current front line biplane fighters, the design of the Hurricane's construction was already considered to be somewhat outdated when introduced to service and resembled those used on the earlier biplanes. Hawker had decided to employ its traditional construction techniques instead of radical measures such as the adoption of a stressed-skin metal exterior. The primary structure comprised a Warren truss box-girder that made use of high-tensile steel longerons and duralumin cross-bracing, which were mechanically fastened instead of welded. Over this, a secondary structure composed of wooden formers and stringers gave the fuselage a rounded external shape, which carried a doped linen covering. The majority of the external surfaces were linen, save for a section between the cockpit and the engine cowling that used lightweight metal panels instead.