PZL.37 Los
Encyclopedia
The PZL
.37 Łoś (moose
) was a Polish
twin-engine medium bomber
, used in the defense of Poland against the Nazi German Invasion
in 1939. It is sometimes known as "PZL P-37" or "PZL P.37", but the letter "P" was generally reserved for fighters of Zygmunt Pulawski
's design (such as the PZL P.11
). The correct designation should be PZL.37.
factory in Warsaw
by Jerzy Dąbrowski
.
The first PZL.37/I prototype, fitted with a single vertical stabilizer, flew on 13 December 1936. The second prototype PZL.37/II, with twin vertical stabilizers and other improvements, was accepted for production. The first 10 serial aircraft were produced in 1938 as the PZL.37A variant with a single vertical stabilizer, however. The next 19 interim aircraft were built as PZL.37A bis, with a twin tail. They all were powered by Bristol Pegasus XII B radial engine
s produced in Poland under licence.
The main production variant, the PZL.37B (or: Łoś II), was fitted with the twin tail and newer Pegasus XX engines. Production of PZL.37B for the Polish Air Force
started in autumn 1938. During the initial period of PZL.37 service, 2 prototypes and 6 serial planes, were lost in crashes caused by technical problems, mostly with rudders. After some structural changes, the PZL.37B became a fully reliable aircraft. By the outbreak of World War II
, about 92 PZL.37s had been produced and given to the Air Force, and a further 31 were in different phases of production.
Before the war, the PZL.37B Łoś was one of the world's most modern bombers. It was able to carry a heavier bombload than similar aircraft, for example the Vickers Wellington
, though the size of the bombs was limited. Smaller than most contemporary medium bombers, it was relatively fast and easy to handle. Thanks to a landing gear with double wheels it could operate from rough fields or meadows. Typically for the late 1930s, its defensive armament consisted of only 3 machine gun
s, which proved too weak against enemy fighters.
Starting with a presentation at a salon in Belgrade
in June 1938 and in Paris
in November, the PZL.37 met with a huge interest. For export purposes, new variants were developed: the PZL.37C with Gnome-Rhone 14N
-0/1 engines of 985 cv (971 BHP, 724 kW), maximum speed 445 km/h and the PZL.37D with 14N-20/21 of 1,065 cv (1,050 BHP, 783 kW), maximum speed 460 km/h. In 1939, 20 PZL.37Cs were ordered by Yugoslavia, 12 by Bulgaria
, 30 PZL.37Ds and license by Romania
and 10, raw materials and parts for next 25 and license by Turkey
and, finally, 12 aircraft for Greece
. Belgian company Renard received permission for license production 20-50 aircraft for Republican Spain but resigned in 1939. Also Denmark, Estonia, Finland and Iran were negotiating. The Polish military weren't allowed a deal with Iran due to "lack of production abilities". The outbreak of the war prevented the production of these aircraft. At that time, PZL developed the next variant for the Polish airforce, the PZL.49 Miś, but this was not completed before the war. Having slightly bigger dimensions, Miś ("Bear") was to be fitted with Bristol Hercules
II engines of 1,350 BHP (1,370 cv, 1,007 kW), maximum speed 520 km/h and an upper turret.
(also used in many other successful Polish airframes incl. PZL P.11
) was planned for the aircraft; the need to store bombs inside wings forced modifications. Some publications claim the resulting profile displayed laminar-flow
properties (one of the first in the world), but this is disputed - its shape which resembled laminar flow wings developed in later years, but this was largely fortuitous, and at any rate achieving the laminar flow regime would have required additional construction features (most importantly extremely smooth wings shaped with extreme precision) which the aircraft simply lacked. However, the profile did display lower drag than expected and the first A version had maximal speed 10% higher than the originally planned 360 km/h. The modified profile was viewed as highly successful and was later re-used for other projects (sometimes in further modified form; e.g. PZL.46 Sum
, PZL.49 Miś, PZL.50
).
The aircraft was quite small for its bomb load and range; it was allowed in part by a lift-generating, airfoil-shaped fuselage, which was another then-unusual feature (previously used e.g. on PZL.26
sports plane). It was much shorter and had smaller wings than many German and French counterparts; it was slightly larger than the Lockheed Model 10 Electra
Amelia Earhart
used. The crew consisted of four: pilot, commander-bombardier, radio operator and a rear gunner. The bombardier was accommodated in the glazed nose, with a forward machine gun. The radio operator sat inside the fuselage, above the bomb bay
, and he also operated an underbelly rear machine gun. The main undercarriage retracted into the engine nacelles. The undercarriage was double-wheeled, with an independent suspension for each wheel. The plane was powered by two Bristol Pegasus radial engine
s. The PZL.37A had Pegasus XII B engines (normal power: 860 BHP (873 cv, 642 kW), maximum: 940 BHP (953 cv, 701 kW)), the PZL.37B had Pegasus XX engines (normal power: 905 HP (918 cv, 675 kW), maximum: 970 BHP (984 cv, 723 kW)).
The bombs were carried in two-section bomb bay in the fuselage (with space for 4 bombs) and 8 bomb bays in the central section of the wings (with space for 16 bombs). This arrangement of bomb bays imposed considerable restrictions on the types of bombs that could be carried, especially in the wing bays which were quite small as they had to fit between the ribs
of the wing. The maximum load was 2,580 kg (2 × 300 kg and 18 × 110 kg). Apart from two 300 kg bombs in one of the fuselage bomb bays, it could not carry bombs larger than 110 kg. With maximum loadout, most of the weight of the bombs was carried inside the wings. There were no provisions for mounting bombs on the outside of the aircraft. During the Invasion of Poland
in 1939, 110 kg was the maximum weight used, since the 300 kg bombs were only available in small quantities, and difficult to load at improvised airfields with little infrastructure. 50 kg bombs were also used. Maximal bomb load taken from soft surface runways was reduced to about 800–1200 kg.
: dywizjon; the PZL.37 were in groups X and XV). The rest of the Bomber Brigade aircraft were PZL.23 Karaś
. About 50 remaining PZL.37s were in the reserve XX group, training units or in repairs. Since only a few months were available to train the crews and complete the equipping of the bombers, the planes were not fully ready when the war broke out. For example, the extra internal fuel tanks were not in service, thus the maximum range of the bomber quoted in specifications was in practice not achievable.
Only the PZL.37s of the Bomber Brigade took part in combat. By 1 September, they had been deployed to rural improvised airfields, so they were not destroyed on the ground by the Germans in their initial attack on the main Polish airbases. However, because of this move away from developed airfields to short fields with poor surfaces, during the campaign the planes could take off with only a fraction of their maximum bomb load (typically 800 kg or 8 x 100 kg bombs), which limited their effectiveness. During the Invasion of Poland
, from 4 September onward the planes of the Bomber Brigade were attacking German armoured columns in day attacks, forced by the desperate situation to perform this mission for which they were not designed (the original plans to bomb targets inside Germany were quickly abandoned). Most notably, they hampered the advance of the 16th Armoured Corps near Częstochowa
and Radomsko
. They suffered heavy losses due to lack of fighter protection, especially because they usually operated in units of no more than three aircraft at a time. The last combat flights took place on 16 September. During the campaign, the combat units were reinforced with several other aircraft, and about 46 PZL.37s were used in combat. Of Bomber Brigade, ten PZL.37s were shot down by fighters, five shot down by enemy anti-aircraft artillery, two bombed on the ground and a further ten lost in other ways. A number of not fully completed, training or reserve PZL.37s were also destroyed on airfields and in factories (18 PZL.37s were bombed in a reserve base in Małaszewicze and in a factory in Warsaw
– Okęcie
).
Twenty-six or twenty-seven PZL.37s (17 from the Bomber Brigade and ten training ones) were withdrawn in 1939 to Romania
. In October 1940, they were seized by the Romanian government and 23 were next used by the Romanian air force in the 4th Group, consisting of the 76th and 77th bomber escadres. Some were uparmed with four machine guns (the Polish PWU machineguns were still used). About one third were lost in crashes due to lack of experience of Romanian pilots with the PZL.37's handling and its high wing loading, and due to engine faults. About 15 were used against the USSR from 22 June 1941. Among others, they first operated in Bessarabia
, then they were bombing Kiev
and Odessa
. Some were lost, mostly due to anti-aircraft fire. Due to a lack of spare parts, the remaining planes were withdrawn from the front in October 1941 and used for training. In April 1944, the 76th escadrille returned to combat, with nine aircraft, but it was withdrawn from the front on 3 May 1944. After Romania joined the Allies, on 1 September 1944, German aircraft destroyed five PZL.37s on a ground.
Captured planes were also tested in Germany and the USSR. Not many PZL.37s fell into German hands (probably only two), because Polish workers scrapped about 30 PZL.37s remaining in factories in Okęcie and Mielec in October 1939, under the pretext of cleaning up the area, before the German authorities were able to reconnoiter. There are no surviving PZL.37 aircraft.
PZL.37/II
PZL.37A
PZL.37Abis
PZL.37B version I and II
PZL.37C
PZL.37D
Germany
Planned:
Greece
Spanish Republic
Kingdom of Yugoslavia
PZL
PZL was the main Polish aerospace manufacturer of the interwar period, based in Warsaw, functioning in 1928-1939...
.37 Łoś (moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...
) was a Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
twin-engine medium bomber
Medium bomber
A medium bomber is a bomber aircraft designed to operate with medium bombloads over medium distances; the name serves to distinguish them from the larger heavy bombers and smaller light bombers...
, used in the defense of Poland against the Nazi German Invasion
Invasion of Poland (1939)
The Invasion of Poland, also known as the September Campaign or 1939 Defensive War in Poland and the Poland Campaign in Germany, was an invasion of Poland by Germany, the Soviet Union, and a small Slovak contingent that marked the start of World War II in Europe...
in 1939. It is sometimes known as "PZL P-37" or "PZL P.37", but the letter "P" was generally reserved for fighters of Zygmunt Pulawski
Zygmunt Pulawski
Zygmunt Puławski was a Polish aircraft designer and pilot. He invented a gull-wing aircraft design, also known as "Puławski wing" and constructed a series of Polish PZL fighters...
's design (such as the PZL P.11
PZL P.11
The PZL P.11 was a Polish fighter aircraft, designed in the early 1930s by PZL in Warsaw. It was briefly considered to be the most advanced fighter aircraft design in the world...
). The correct designation should be PZL.37.
Design and development
The PZL.37 was designed in the mid-1930s at the PZLPZL
PZL was the main Polish aerospace manufacturer of the interwar period, based in Warsaw, functioning in 1928-1939...
factory in Warsaw
Warsaw
Warsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...
by Jerzy Dąbrowski
Jerzy Dabrowski
Jerzy Dąbrowski was a Polish aeronautical engineer. He was the lead designer of the famed PZL.37 Łoś medium bomber....
.
The first PZL.37/I prototype, fitted with a single vertical stabilizer, flew on 13 December 1936. The second prototype PZL.37/II, with twin vertical stabilizers and other improvements, was accepted for production. The first 10 serial aircraft were produced in 1938 as the PZL.37A variant with a single vertical stabilizer, however. The next 19 interim aircraft were built as PZL.37A bis, with a twin tail. They all were powered by Bristol Pegasus XII B radial engine
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
s produced in Poland under licence.
Polish Air Force
The Polish Air Force is the military Air Force wing of the Polish Armed Forces. Until July 2004 it was officially known as Wojska Lotnicze i Obrony Powietrznej...
started in autumn 1938. During the initial period of PZL.37 service, 2 prototypes and 6 serial planes, were lost in crashes caused by technical problems, mostly with rudders. After some structural changes, the PZL.37B became a fully reliable aircraft. By the outbreak of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, about 92 PZL.37s had been produced and given to the Air Force, and a further 31 were in different phases of production.
Before the war, the PZL.37B Łoś was one of the world's most modern bombers. It was able to carry a heavier bombload than similar aircraft, for example the Vickers Wellington
Vickers Wellington
The Vickers Wellington was a British twin-engine, long range medium bomber designed in the mid-1930s at Brooklands in Weybridge, Surrey, by Vickers-Armstrongs' Chief Designer, R. K. Pierson. It was widely used as a night bomber in the early years of the Second World War, before being displaced as a...
, though the size of the bombs was limited. Smaller than most contemporary medium bombers, it was relatively fast and easy to handle. Thanks to a landing gear with double wheels it could operate from rough fields or meadows. Typically for the late 1930s, its defensive armament consisted of only 3 machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
s, which proved too weak against enemy fighters.
Starting with a presentation at a salon in Belgrade
Belgrade
Belgrade is the capital and largest city of Serbia. It is located at the confluence of the Sava and Danube rivers, where the Pannonian Plain meets the Balkans. According to official results of Census 2011, the city has a population of 1,639,121. It is one of the 15 largest cities in Europe...
in June 1938 and in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
in November, the PZL.37 met with a huge interest. For export purposes, new variants were developed: the PZL.37C with Gnome-Rhone 14N
Gnome-Rhône 14N
|-See also:* Pratt & Whitney R-1830 a comparable engine sometimes fitted as an alternative to the 14N on French designs* BMW 801* Bristol Hercules* Wright R-2600* Fiat A.74* Mitsubishi Kinsei* Nakajima Sakae* Shvetsov ASh-82-References:...
-0/1 engines of 985 cv (971 BHP, 724 kW), maximum speed 445 km/h and the PZL.37D with 14N-20/21 of 1,065 cv (1,050 BHP, 783 kW), maximum speed 460 km/h. In 1939, 20 PZL.37Cs were ordered by Yugoslavia, 12 by Bulgaria
Bulgarian Air Force
The Bulgarian Air Force is a branch of the Military of Bulgaria, the other two being the Bulgarian Navy and Bulgarian land forces. Its mission is to guard and protect the sovereignty of Bulgarian airspace, to provide aerial support and to assist the Land Forces in case of war. The Bulgarian Air...
, 30 PZL.37Ds and license by Romania
Romanian Air Force
The Romanian Air Force is the air force branch of the Romanian Armed Forces. It has an air force headquarters, an operational command, four air bases and an air defense brigade...
and 10, raw materials and parts for next 25 and license by Turkey
Turkish Air Force
The Turkish Air Force is the aerial warfare service branch of the Turkish Armed Forces. It ranks 3rd in NATO in terms of fleet size behind the USAF and Royal Air Force with a current inventory of 798 aircraft .-Initial stages:...
and, finally, 12 aircraft for Greece
Hellenic Air Force
The Hellenic Air Force, abbreviated to HAF is the air force of Greece. The mission of the Hellenic Air Force is to guard and protect Greek airspace, provide air assistance and support to the Hellenic Army and the Hellenic Navy, as well as the provision of humanitarian aid in Greece and around the...
. Belgian company Renard received permission for license production 20-50 aircraft for Republican Spain but resigned in 1939. Also Denmark, Estonia, Finland and Iran were negotiating. The Polish military weren't allowed a deal with Iran due to "lack of production abilities". The outbreak of the war prevented the production of these aircraft. At that time, PZL developed the next variant for the Polish airforce, the PZL.49 Miś, but this was not completed before the war. Having slightly bigger dimensions, Miś ("Bear") was to be fitted with Bristol Hercules
Bristol Hercules
|-See also:-Bibliography:*Gunston, B. Classic World War II Aircraft Cutaways. Osprey. ISBN 1-85532-526-8*Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9...
II engines of 1,350 BHP (1,370 cv, 1,007 kW), maximum speed 520 km/h and an upper turret.
Technical design
The aircraft was conventional in layout, all metal, metal-covered, with low-set wings and a twin tail. Originally a popular profile designed by Ryszard BartelRyszard Bartel
Ryszard Bartel was a Polish engineer, aircraft designer and aviator, one of Poland's aviation pioneers.Bartel was born in Sławniów village near Pilica. He was interested in aviation from his youth, and in 1911 he built his own gliders capable of short flights...
(also used in many other successful Polish airframes incl. PZL P.11
PZL P.11
The PZL P.11 was a Polish fighter aircraft, designed in the early 1930s by PZL in Warsaw. It was briefly considered to be the most advanced fighter aircraft design in the world...
) was planned for the aircraft; the need to store bombs inside wings forced modifications. Some publications claim the resulting profile displayed laminar-flow
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
properties (one of the first in the world), but this is disputed - its shape which resembled laminar flow wings developed in later years, but this was largely fortuitous, and at any rate achieving the laminar flow regime would have required additional construction features (most importantly extremely smooth wings shaped with extreme precision) which the aircraft simply lacked. However, the profile did display lower drag than expected and the first A version had maximal speed 10% higher than the originally planned 360 km/h. The modified profile was viewed as highly successful and was later re-used for other projects (sometimes in further modified form; e.g. PZL.46 Sum
PZL.46 Sum
-See also:- References :* Andrzej Glass: "Polskie konstrukcje lotnicze 1893-1939" , WKiŁ, Warsaw 1977 - External links :*...
, PZL.49 Miś, PZL.50
PZL.50
The PZL.50 Jastrząb was a Polish pre-war fighter aircraft designed by Wsiewołod Jakimiuk of the PZL works. The single-seat low-wing monoplane was to serve as a multi-purpose fighter and escort to replace all fighters used previously by the Polish Air Force. Designed after 1936, its prototype was...
).
The aircraft was quite small for its bomb load and range; it was allowed in part by a lift-generating, airfoil-shaped fuselage, which was another then-unusual feature (previously used e.g. on PZL.26
PZL.26
|-References:*Andrzej Glass: Polskie konstrukcje lotnicze 1893-1939 , WKiŁ, Warsaw 1977 -See also:...
sports plane). It was much shorter and had smaller wings than many German and French counterparts; it was slightly larger than the Lockheed Model 10 Electra
Lockheed Model 10 Electra
The Lockheed Model 10 Electra was a twin-engine, all-metal monoplane airliner developed by the Lockheed Aircraft Corporation in the 1930s to compete with the Boeing 247 and Douglas DC-2...
Amelia Earhart
Amelia Earhart
Amelia Mary Earhart was a noted American aviation pioneer and author. Earhart was the first woman to receive the U.S. Distinguished Flying Cross, awarded for becoming the first aviatrix to fly solo across the Atlantic Ocean...
used. The crew consisted of four: pilot, commander-bombardier, radio operator and a rear gunner. The bombardier was accommodated in the glazed nose, with a forward machine gun. The radio operator sat inside the fuselage, above the bomb bay
Bomb bay
The bomb bay or weapons bay on some military aircraft is a compartment to carry bombs, usually in the aircraft's fuselage, with "bomb bay doors" which open at the bottom. The bomb bay doors are opened and the bombs are dropped when over the target or at a specified launching point.Large-sized...
, and he also operated an underbelly rear machine gun. The main undercarriage retracted into the engine nacelles. The undercarriage was double-wheeled, with an independent suspension for each wheel. The plane was powered by two Bristol Pegasus radial engine
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
s. The PZL.37A had Pegasus XII B engines (normal power: 860 BHP (873 cv, 642 kW), maximum: 940 BHP (953 cv, 701 kW)), the PZL.37B had Pegasus XX engines (normal power: 905 HP (918 cv, 675 kW), maximum: 970 BHP (984 cv, 723 kW)).
The bombs were carried in two-section bomb bay in the fuselage (with space for 4 bombs) and 8 bomb bays in the central section of the wings (with space for 16 bombs). This arrangement of bomb bays imposed considerable restrictions on the types of bombs that could be carried, especially in the wing bays which were quite small as they had to fit between the ribs
Rib (aircraft)
In an aircraft, ribs are forming elements of the structure of a wing, especially in traditional construction.By analogy with the anatomical definition of "rib", the ribs attach to the main spar, and by being repeated at frequent intervals, form a skeletal shape for the wing...
of the wing. The maximum load was 2,580 kg (2 × 300 kg and 18 × 110 kg). Apart from two 300 kg bombs in one of the fuselage bomb bays, it could not carry bombs larger than 110 kg. With maximum loadout, most of the weight of the bombs was carried inside the wings. There were no provisions for mounting bombs on the outside of the aircraft. During the Invasion of Poland
Invasion of Poland (1939)
The Invasion of Poland, also known as the September Campaign or 1939 Defensive War in Poland and the Poland Campaign in Germany, was an invasion of Poland by Germany, the Soviet Union, and a small Slovak contingent that marked the start of World War II in Europe...
in 1939, 110 kg was the maximum weight used, since the 300 kg bombs were only available in small quantities, and difficult to load at improvised airfields with little infrastructure. 50 kg bombs were also used. Maximal bomb load taken from soft surface runways was reduced to about 800–1200 kg.
Operational history
The Polish Air Force started to receive the Łos A in early 1938, with deliveries of the PZL.37B to operational units , slowed by delays in supply of the Pegasus XX engines and other equipment, in the autumn of 1938. On 1 September 1939, it had about 86 PZL.37s in total, but less than a half of those were used in combat. 36 PZL.37Bs were in four bomber escadres of a Bomber Brigade: the 11th, 12th, 16th and 17th escadres (two escadres with nine aircraft each, constituted a group, in PolishPolish language
Polish is a language of the Lechitic subgroup of West Slavic languages, used throughout Poland and by Polish minorities in other countries...
: dywizjon; the PZL.37 were in groups X and XV). The rest of the Bomber Brigade aircraft were PZL.23 Karaś
PZL.23 Karas
|-Specifications :-See also:-References:NotesBibliography* Angelucci, Enzo and Paolo Matricardi. World War II Airplanes . Chicago: Rand McNally, 1978. ISBN 0-52888-170-1....
. About 50 remaining PZL.37s were in the reserve XX group, training units or in repairs. Since only a few months were available to train the crews and complete the equipping of the bombers, the planes were not fully ready when the war broke out. For example, the extra internal fuel tanks were not in service, thus the maximum range of the bomber quoted in specifications was in practice not achievable.
Only the PZL.37s of the Bomber Brigade took part in combat. By 1 September, they had been deployed to rural improvised airfields, so they were not destroyed on the ground by the Germans in their initial attack on the main Polish airbases. However, because of this move away from developed airfields to short fields with poor surfaces, during the campaign the planes could take off with only a fraction of their maximum bomb load (typically 800 kg or 8 x 100 kg bombs), which limited their effectiveness. During the Invasion of Poland
Invasion of Poland (1939)
The Invasion of Poland, also known as the September Campaign or 1939 Defensive War in Poland and the Poland Campaign in Germany, was an invasion of Poland by Germany, the Soviet Union, and a small Slovak contingent that marked the start of World War II in Europe...
, from 4 September onward the planes of the Bomber Brigade were attacking German armoured columns in day attacks, forced by the desperate situation to perform this mission for which they were not designed (the original plans to bomb targets inside Germany were quickly abandoned). Most notably, they hampered the advance of the 16th Armoured Corps near Częstochowa
Czestochowa
Częstochowa is a city in south Poland on the Warta River with 240,027 inhabitants . It has been situated in the Silesian Voivodeship since 1999, and was previously the capital of Częstochowa Voivodeship...
and Radomsko
Radomsko
Radomsko is a town in central Poland with 50,618 inhabitants . It is situated on the Radomka river in the Łódź Voivodeship , having previously been in Piotrków Trybunalski Voivodeship . It is the capital of Radomsko County....
. They suffered heavy losses due to lack of fighter protection, especially because they usually operated in units of no more than three aircraft at a time. The last combat flights took place on 16 September. During the campaign, the combat units were reinforced with several other aircraft, and about 46 PZL.37s were used in combat. Of Bomber Brigade, ten PZL.37s were shot down by fighters, five shot down by enemy anti-aircraft artillery, two bombed on the ground and a further ten lost in other ways. A number of not fully completed, training or reserve PZL.37s were also destroyed on airfields and in factories (18 PZL.37s were bombed in a reserve base in Małaszewicze and in a factory in Warsaw
Warsaw
Warsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...
– Okęcie
Okecie
Okęcie is the largest neighbourhood of the Włochy district of Warsaw, Poland.It is the location of Warsaw Chopin Airport and the PZL Warszawa-Okęcie aircraft works, and home to the Okęcie Warszawa professional association football club....
).
Twenty-six or twenty-seven PZL.37s (17 from the Bomber Brigade and ten training ones) were withdrawn in 1939 to Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
. In October 1940, they were seized by the Romanian government and 23 were next used by the Romanian air force in the 4th Group, consisting of the 76th and 77th bomber escadres. Some were uparmed with four machine guns (the Polish PWU machineguns were still used). About one third were lost in crashes due to lack of experience of Romanian pilots with the PZL.37's handling and its high wing loading, and due to engine faults. About 15 were used against the USSR from 22 June 1941. Among others, they first operated in Bessarabia
Bessarabia
Bessarabia is a historical term for the geographic region in Eastern Europe bounded by the Dniester River on the east and the Prut River on the west....
, then they were bombing Kiev
Kiev
Kiev or Kyiv is the capital and the largest city of Ukraine, located in the north central part of the country on the Dnieper River. The population as of the 2001 census was 2,611,300. However, higher numbers have been cited in the press....
and Odessa
Odessa
Odessa or Odesa is the administrative center of the Odessa Oblast located in southern Ukraine. The city is a major seaport located on the northwest shore of the Black Sea and the fourth largest city in Ukraine with a population of 1,029,000 .The predecessor of Odessa, a small Tatar settlement,...
. Some were lost, mostly due to anti-aircraft fire. Due to a lack of spare parts, the remaining planes were withdrawn from the front in October 1941 and used for training. In April 1944, the 76th escadrille returned to combat, with nine aircraft, but it was withdrawn from the front on 3 May 1944. After Romania joined the Allies, on 1 September 1944, German aircraft destroyed five PZL.37s on a ground.
Captured planes were also tested in Germany and the USSR. Not many PZL.37s fell into German hands (probably only two), because Polish workers scrapped about 30 PZL.37s remaining in factories in Okęcie and Mielec in October 1939, under the pretext of cleaning up the area, before the German authorities were able to reconnoiter. There are no surviving PZL.37 aircraft.
Variants
PZL.37/I- First prototype with a single tail fin.
PZL.37/II
- First prototype with a double tail fins and improvements.
PZL.37A
- First 10 serial aircraft with single tail, Bristol Pegasus XIIB engines.
PZL.37Abis
- Batch of 19 serial aircraft of A version with double tail fins.
PZL.37B version I and II
- Main production variant with double tail fins and PZL Pegaz XX engines.
PZL.37C
- Planned version with Gnome-Rhône 14N-01Gnome et RhôneGnome et Rhône was a major French aircraft engine manufacturer. Between 1914 and 1918 they produced 25,000 of their 9-cylinder Delta and Le Rhône 110 hp rotary designs, while another 75,000 were produced by various licensees, powering the majority of aircraft in the first half of the war on...
engines.
PZL.37D
- Planned version with Gnome-Rhône 14N-21Gnome et RhôneGnome et Rhône was a major French aircraft engine manufacturer. Between 1914 and 1918 they produced 25,000 of their 9-cylinder Delta and Le Rhône 110 hp rotary designs, while another 75,000 were produced by various licensees, powering the majority of aircraft in the first half of the war on...
engines.
Operators
Wartime:- Polish Air ForcePolish Air ForceThe Polish Air Force is the military Air Force wing of the Polish Armed Forces. Until July 2004 it was officially known as Wojska Lotnicze i Obrony Powietrznej...
- Brygada BombowaBomber BrigadeThe Bomber Brigade was a World War II unit of the Polish Air Force commanded by płk obs. Władysław Heller. It resisted the Invasion of Poland in 1939 as the main aerial reserve of the commander in chief and was used for bombing enemy units in central Poland. It was created just before the war and...
- X Dywizjon Bombowy
- 211. Eskadra Bombowa
- 212. Eskadra Bombowa
- XV Dywizjon Bombowy
- 216. Eskadra Bombowa
- 217. Eskadra Bombowa
- X Dywizjon Bombowy
- Brygada Bombowa
Germany
- LuftwaffeLuftwaffeLuftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
operated two captured PZL.37s for testing purposes.
- Royal Romanian Air ForceRoyal Romanian Air ForceThe Forţele Aeriene Regale ale României , or simply Forţele Aeriene Române was the Air Arm of Royal Romanian forces in World War II...
- Grupul 4 Bombardament
- Escadrila 76
- Escadrila 77
- Grupul 4 Bombardament
- Soviet Air ForceSoviet Air ForceThe Soviet Air Force, officially known in Russian as Военно-воздушные силы or Voenno-Vozdushnye Sily and often abbreviated VVS was the official designation of one of the air forces of the Soviet Union. The other was the Soviet Air Defence Forces...
operated three captured PZL.37s for testing purposes.
Planned:
- Bulgarian Air ForceBulgarian Air ForceThe Bulgarian Air Force is a branch of the Military of Bulgaria, the other two being the Bulgarian Navy and Bulgarian land forces. Its mission is to guard and protect the sovereignty of Bulgarian airspace, to provide aerial support and to assist the Land Forces in case of war. The Bulgarian Air...
ordered 12 PZL.37Cs. The start of World War II did not allow them to be delivered.
Greece
- Hellenic Air ForceHellenic Air ForceThe Hellenic Air Force, abbreviated to HAF is the air force of Greece. The mission of the Hellenic Air Force is to guard and protect Greek airspace, provide air assistance and support to the Hellenic Army and the Hellenic Navy, as well as the provision of humanitarian aid in Greece and around the...
ordered 12 aircraft.
Spanish RepublicSecond Spanish Republic
The Second Spanish Republic was the government of Spain between April 14 1931, and its destruction by a military rebellion, led by General Francisco Franco....
- Spanish Air ForceSpanish Air Force-The early stages:Hot air balloons had been used with military purposes in Spain as far back as 1896. In 1905, with the help of Alfredo Kindelán, Leonardo Torres y Quevedo directed the construction of the first Spanish dirigible in the Army Military Aerostatics Service, created in 1896 and located...
- Turkish Air ForceTurkish Air ForceThe Turkish Air Force is the aerial warfare service branch of the Turkish Armed Forces. It ranks 3rd in NATO in terms of fleet size behind the USAF and Royal Air Force with a current inventory of 798 aircraft .-Initial stages:...
ordered ten PZL.37Ds, materials for next 25 and license rights.
Kingdom of Yugoslavia
- Yugoslav Royal Air ForceYugoslav Royal Air ForceThe Yugoslav Royal Air Force was formed in 1918 in the Kingdom of Serbs, Croats and Slovenes and existed until Yugoslavia's surrender to the Axis powers in 1941 following the Invasion of Yugoslavia during World War II....
ordered 20 PZL.37Cs.