Польшаның LWS 6 Żubr бомбалаушысы тарихы

The LWS 6 Żubr (PZL.30, wisent) was a twin engined medium bomber designed and produced by the Polish aircraft manufacturer LWS. It was only produced in limited numbers and was used for training purposes as it proved to be inferior to the contemporary PZL.37 Łoś medium bomber. The LWS 6 was originally designed as a 12 passenger airliner during the early 1930s, but was reconfigured to produce bomber instead. During March 1936, the first prototype, designated PZL.30 (or PZL.30BI), performed its maiden flight. The aircraft was accepted for a limited production run by the LWS state factory in Lublin for the Polish Air Force. During 1937, work commenced on a floatplane torpedo bomber variant, designated the LWS 5, for the Polish Navy, but work on the prototype was abandoned following setbacks. Export sales were also sought, the Romanian Air Force were reportedly considering buying up to 24 aircraft, however, following the loss of one of the prototypes on 7 November 1936 due to a mid air structural failure, Romania ordered the rival PZL.37 Łoś instead. During 1938, the LWS 6 was introduced to service with the Polish Air Force, which immediately assigned the type to its training units rather than frontline squadrons. Even so, its service life would be relatively brief on account of the outbreak of the Second World War in September 1939. Many aircraft were destroyed on the ground, none would be used in combat against Nazi Germany. Several would be captured by both the Soviet Union and Germany, leading to the type being used in secondary roles, such as training and communication, by the Luftwaffe and the Soviet Air Forces. None would survive the conflict.

Work on what would become the LWS 6 originally started in 1932 as the PZL.30, a 12 passenger airliner. While the airline did not outwardly indicate interest in the project, Polish aviation authorities opted to sponsor its development in the hope that LOT would change its mind as it neared completion. Such hopes were in vain, however, as in 1935, LOT opted to purchase American built Douglas DC 2 airliners instead. Another avenue for the project had prevented itself in the form of an official requirement for a new medium bomber for the Polish Air Force; Ciołkosz himself proposed producing a bomber derivative of his airliner project. Continuing the PZL.30's development also enabled the project to act as a fallback option in the eventuality that the more advanced bomber encountered insurmountable technical issues. Thus, the company was instructed to proceed with constructing a single prototype. It was flown in September 1936. The aircraft was accepted for a limited production run by the LWS state factory in Lublin, for which Ciołkosz was appointed the technical director and project lead. In older publications there could be found a designation LWS 4, but it does not appear in any documents and the aircraft's correct designation was LWS 6.

It was planned to produce 16 aircraft for the Polish Air Force, with the designation: LWS 6 Żubr. To remedy the issue, the wing was redesigned with greater reinforcement, but this measure increased the aircraft's overall weight, which in turn meant that the LWS 6 had a smaller bomb load than expected while other performance areas were also hampered.|group=Note

As one part of several measures explored to improve the aircraft's performance, a modified prototype was produced that featured a double tail fin; it conducted an initial flight near the end of 1937. However, the definitive model that would attain quantity production would only ever use a single tail fin configuration, albeit enlarged from earlier counterparts. During 1938, a series of 15 aircraft were constructed, while deliveries to the Polish Air Force commenced in early 1939. These engines drove three bladed Hamilton Standard metal propellers. The engines were license manufactured as PZL Pegaz 8. The LWS 6 was operated by a crew of four: a pilot, commander bombardier, radio operator and a rear gunner. The bombardier was accommodated in the aircraft's glazed nose, the position being provisioned with a forward facing turret armed with twin machine guns that had a distinctive pointed "beard" directly beneath it. The pilot was seated underneath a sizable canopy in a forward position on the upper fuselage, which was also somewhat offset to the left. The radio operator was seated inside the fuselege. In training role, additional crew member took place in the pilot's cockpit on folding seat. The rear gunner operated a semi retractable upper dorsal turret armed with twin machine guns that elevated to a working position, along with a "trap" ventral position that operated in an identical manner. The bombload was intended to be primarily carried within an internal bomb bay on multi storey racks; external racks were also tested for an expanded bombing capacity. The type was exclusively used for training. Production model of the Żubr was considered safe aircraft, with good flight characteristics, and only one crashed before the war due to pilot's error, however, without fatal injuries. During the Invasion of Poland in September 1939, no Żubrs were recorded as having been used in actual combat. They were largely grounded, being unsuitable for operations at full loaded weight from the temporary operational landing fields commonly being used, while flying in a lightened condition would have provided virtually no payload capacity. The Soviet Union also captured four aircraft during their own invasion of Poland. These were subsequently operated by the Soviet Air Forces for a time as communication aircraft.

Luftwaffe — operated captured aircraft for training purposes. Polish Air Force — used in non combat roles, primarily training. Soviet Air Force — used four captured aircraft for communication.