Two Aircraft identification Plates of a Heinkel 111 airplane shot down by the Royal Air Force (RAF) in 1940. The label reads "Identification plates of a Heinkel 111 made by der elves in der Black Forest September 14, 1938 'Kaput' RAF September 1940." "Large tag "ARADO - Fleugseugwerke G.m. The Heinkel He 111 was a German aircraft designed by Siegfried and Walter Günter at Heinkel Flugzeugwerke in the early 1930s. It has sometimes been described as a "wolf in sheep's clothing" because it masqueraded as a cargo plane though its actual purpose was to provide the nascent Luftwaffe with a fast medium bomber. (Germany had been prohibited by the 1919 Treaty of Versailles from having an air force.) Perhaps the best-recognised German bomber due to the distinctive, extensively glazed "greenhouse" nose of later versions, the Heinkel 111 was the most numerous and the primary Luftwaffe bomber during the early stages of World War II. It fared well until the Battle of Britain, when its weak defensive armament, relatively low speed, and poor manoeuvrability were exposed. Nevertheless, it proved capable of sustaining heavy damage and remaining airborne. As the war progressed, the He 111 was used in a variety of roles on every front in the European theatre. It was used as a strategic bomber during the Battle of Britain, a torpedo bomber during the Battle of the Atlantic, and a medium bomber and a transport aircraft on the Western, Eastern, Mediterranean, Middle Eastern, and North African Fronts. Although constantly upgraded, the Heinkel He 111 became obsolete during the latter part of the war. Battle of Britain Luftflotte 2 and Luftflotte 3 committed 34 Gruppen to the campaign over Britain. Fifteen of them were equipped with the He 111. The remainder were mixed Do 17 and Ju 88 units. The He 111 and Ju 88 were equal in performance in all but speed, in which the Ju 88 was faster. The Do 17 was also faster, but lacked the heavy bomb load capabilities of the Ju 88 and He 111. During the Battle of Britain the Heinkels ability to take heavy punishment was one of its strengths and it suffered fewer losses than the Ju 88. The battle highlighted the need for heavier defensive armament and effective fighter protection by the Messerschmitt Bf 109 and Messerschmitt Bf 110 units if losses were to be kept to sustainable levels. The concentration of most of the crew in the glass nose made the He 111 vulnerable to concentrated fire from a head-on attack. The advantages won in July and August were lost by the switch of strategy to bombing British cities and industrial centres, (known as the Blitz) on 7 September 1940. The He 111 was now being asked to perform in the role of the strategic bomber. Despite the fact that it lacked the load-carrying capacity of later heavy bombers, the He 111 still carried enough destructive power to cause severe damage to strategic targets; the de Havilland Mosquito factory near Bristol was devastated by Kampfgeschwader 53 on 30 August. A month later, the Woolston Supermarine Spitfire factory was destroyed largely by He 111s of Kampfgeschwader 55 on 26 September, forcing the factory's closure and dispersal, though the disruption to production was, at that time, not as serious as it would have been in July/August 1940. He 111s were fitted with the Knickebein and used it for blind-bombing during the Blitz, leading to the Battle of the Beams. This system, fitted to all German bombers, enabled the He 111 to bomb targets during the night without visual contact. Some special Pfadfinder (Pathfinder) units such as Kampgruppe 100 were equipped with the X-Gerät blind-bombing system and were used to illuminate targets with incendiary bombs for the regular bomber units that followed. Theoretically, it could hit individual buildings, though in practice jamming and other factors tended to decrease its accuracy. Eventually, the Y-Gerät was introduced, as an enhanced version of the previous X-system. On 3 November 1940 the RAF had a chance to evaluate a He 111 that had landed along the coast and was partially submerged with the equipment. A Royal Navy captain who arrived claimed command of the salvage operation as he was a superior rank to the attending Army Officer and insisted the He 111 be towed to deeper water before hoisting it up. The ropes snapped and the He 111 sank. Though the machine was eventually pulled out, but the salt water had got into its Gerät system. The Luftwaffe tried to attack industrial, transport and civilian targets simultaneously but failed to do so. Even so the He 111 contributed to the Birmingham Blitz, Bristol Blitz, Barrow Blitz, Coventry Blitz, Liverpool Blitz, Plymouth Blitz and Southampton Blitz which caused severe damage. Some of these targets were obscured by cloud, but the equipped X-Gerät Heinkels inflicted heavy damage. However the British countered its use with decoy sites to attract the attention of bombers and the "Meacon" system, which disrupted Luftwaffe beacon transmissions. 242 He 111s were destroyed during the course of the battle between July and October 1940, a total substantially lower than the 303 Ju 88s destroyed. The Dornier Do 17s losses in the Battle of Britain amounted to 132 machines destroyed, the lowest losses of the three German bomber types.