page_title: PZL.37 Łoś
section_title: Production
hierarchical_section_title: PZL.37 Łoś / Development / Production
caption_attribution_description: English: PZL.37 Los medium bomber - the second prototype P.37/II Polski: PZL 37B Łoś. Dwusilnikowy średni bombowiec. Na zdjęciu drugi prototyp.
context_page_description: The PZL.37 Łoś was a Polish twin-engined medium bomber designed and manufactured by national aircraft company PZL. It is also known as "PZL P-37" or "PZL P.37", but the letter "P" was generally reserved for fighters of Zygmunt Puławski's design.
  Upon its introduction to service, it was popularly considered to be not only the most modern and effective weapon then possessed by Poland, but also to be one of the most advanced bombers then operational in the world. From mid-1938 onwards, there was huge interest expressed by various nations in potential export sales of the PZL.37; in response to this highly favourable reception, PZL, being keen to meet the demands, developed additional variants that were intended for the export market, such as the PZL.37C. An improved enlarged derivative, known as the PZL.49 Miś, was also developed for the Polish Air Force.
  The Łoś was extensively used in the defense of Poland during the rapid invasion of Poland by Nazi Germany in September 1939.
context_section_description: Production of the Łoś commenced during the winter of 1936-1937. During 1938, the first 10 serial aircraft were manufactured, designated as the PZL.37A; these were furnished with a single vertical stabilizer. The next 19 interim aircraft were constructed to the PZL.37A bis standard, having been outfitted with the newer twin tail configuration. All of these aircraft were powered by the British-developed Bristol Pegasus XII B radial engine, which was produced in Poland under licence.
  The main production variant, the PZL.37B (or: Łoś II), was furnished with the twin tail arrangement along with newer Pegasus XX engines. During autumn 1938, production of the PZL.37B commenced for the Polish Air Force. During the initial period of service, 2 prototypes and 6 serial aircraft were lost in separate crashes; these had been caused by several technical problems, most of which involved the rudder. Following the implementation of some structural changes, the PZL.37B became a highly reliable aircraft. By the outbreak of the Second World War, roughly 92 PZL.37 bombers had been produced and delivered to the Polish Air Force, and a further 31 were in different phases of production.
  Prior to the Second World War, the PZL.37B Łoś was widely considered to be one of the most advanced bombers then operational in the world. It was able to carry a heavier bombload than considerably larger aircraft, such as the British-built Vickers Wellington, though the dimensions of the individual bombs were limited. Being smaller than most contemporary medium bombers, the Łoś was relatively fast and easy to handle. As a consequence of a favourable landing gear arrangement, having been fitted with double wheels, the bomber could operate from austere airstrips as well as rough fields or meadows. Typically amongst bombers of the late 1930s, its defensive armament consisted of only three machine guns, which subsequently proved too weak against enemy fighters in combat.
caption: The second prototype of the PZL.37 Łoś
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