Amongst the clauses of the specification were a wing span of less than 100 ft so as to fit a standard RAF hangar and a fuselage small enough, in cross section, to fit a standard packing case. These peculiar requirements, together with the provision for carrying a large number of small bombs, rather than a few large ones, were responsible for many of the design features which limited the Stirling's performance and eventual usefulness. The prototype flew in May 1939. A year later, the first production Stirling 1 appeared and, by August, the very few Stirlings available were beginning to replace the Wellingtons of No. 7 Squadron. On February 10th, 1941, Stirlings carried out their first mission, a night attack against oil storage tanks at Rotterdam. On May 30th, 1942, Stirlings took part in the first 1,000 bomber raid. In combat Stirlings were showing themselves capable of absorbing amazing battle damage and still returning to base and they continued to be employed in the bombing role until September 1944. Meanwhile, the Stirling had been employed in other roles, including mine-laying, supply dropping and as a transport and glider tug. When production finished in November 1945, 2,375 had been built. Of the two individual aircraft which are featured in this kit, MG-K is a Stirling B.1 of 7 Squadron which operated, first from Leeming in Yorkshire and then from Oakington in Cambridgeshire, with 3 Group. The second aircraft, EX-L is a B.111 of 199 Squadron of 3 Group which flew bombing, mine-laying and supply missions to the Resistance. In 1944, the Squadron moved to North Creake and flew with 100 Group on radio counter-measures until March 1945. The Stirling I was powered by four 1,590 h.p. Bristol Hercules engines, giving a maximum speed of 260 m.p.h. and a range of 1,930 miles with a 5,000 lb bomb load. Defensive armament consisted of eight .303 in machine guns and maximum bomb load was 14,000 lb. Wing span 99 ft 1 in, length 87 ft 3 in.