A key reason for the aircraft's appeal was its relatively simple construction and ease of manufacture. In comparison to the Supermarine Spitfire, it was significantly cheaper and involved less labour, requiring 10,300 man hours to produce versus 15,200 for the Spitfire. As a large-scale war was looking increasingly likely, and time was of the essence in providing the RAF with an effective fighter aircraft, it was unclear if the more advanced Spitfire would enter production smoothly, while the Hurricane made use of well-understood manufacturing techniques. This factor was equally applicable for its use within service squadrons as well, which were experienced in working on and repairing aircraft whose construction employed the same principles as the Hurricane, and the simplicity of its design enabled the improvisation of some remarkable repairs in squadron workshops. A fabric-covered wing patterned upon traditional Hawker designs was initially adopted in order to speed up production; a higher-performing stressed-skin metal wing took its place in late 1939.