PZL.23 Karaś

The PZL.23 Karaś was a Polish light bomber and reconnaissance aircraft designed in the mid-1930s by PZL in Warsaw. It was the main Polish bomber and reconnaissance aircraft used during the Invasion of Poland.

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Design and development:

The aircraft was developed in 1931 to replace Breguet 19 and Potez 25 aircraft in the Polish Air Force. The main designer was Stanisław Prauss who based the design on a passenger transport project PZL.13 that was only a “paper” proposal. The design was of modern all-metal construction with wings built around light closed profiles instead of spars (introduced first in PZL.19). The P.23/I first prototype flew on 1 April 1934, followed by the second P.23/II prototype.

In the third P.23/III prototype of 1935, a pilot’s seat was raised and the engine was lowered to obtain a better view. This prototype was accepted for a production, with the name Karaś (in Polish – the crucian carp). The first series, PZL.23A was fitted with a Bristol Pegasus IIM2 radial engine of 670 hp (500 kW) produced in Poland under licence. Since this engine proved to be unreliable, the final variant PZL.23B was fitted with a newer Pegasus VIII of 720 hp (537 kW).

The aircraft was a low-wing cantilever monoplane of all-metal, metal-covered construction. The crew consisted of three: pilot, bombardier and a rear gunner. The bombardier’s combat station was situated in a gondola underneath the hull, where he could also operate an underbelly machine gun. The fixed undercarriage was well spatted, but despite a massive look, it was not suited for rough airfields. Bombs were carried under the wings: the maximum load was 700 kg (1,500 lb) (6 x 100 kg and 2 x 50 kg). The aircraft were equipped with one of the following engines: Bristol Pegasus IIM2 normal: 570 hp (425 kW), maximum: 670 hp (500 kW) – PZL.23A; Pegasus VIII normal: 650 hp (485 kW), maximum: 720 (537 kW) – PZL.23B. Regardless of the engine, the aircraft had a two-blade propeller.

The Bristol engines were licensed for use in Poland only, so for export purposes the Gnome-Rhône 14K was used in a variety of PZL designs. In this case the 14K-powered PZL.23, with some changes to the airframe, became the PZL.43 Karaś. Final export variant was PZL.23A, with 1,020 hp Gnome-Rhone 14N-01 engine. 52 PZL.43s were made in total, all for Bulgaria only. The new engine improved the aircraft’s performance considerably, maximum speed increased to 365 km/h.

In 1936, 40 PZL.23As were produced. Between late 1936 and February 1938, 210 PZL.23Bs were produced with the new engines. They were also known as Karaś A and B or Karaś I and II. All PZL.23s had military numbers from 44.1 to 44.250.Sometimes the aircraft is called the “PZL P.23”, but despite an abbreviation P.23 painted on a tail fin, the letter “P” was generally reserved for fighters of Pulawski’s design (like PZL P.11). In November 1936, one aircraft was shown at the Paris Air Show, where it was met with interest.

During this period, PZL developed the PZL.46 Sum, a new light bomber, partly based on the PZL.23 design, but only two prototypes were completed in 1938. There was also a single experimental variant of the Karaś, PZL.42, with double tail fins and a modified bombardier gondola, retractable into the fuselage.

Operational history:

Forty PZL.23As were delivered to the Polish Air Force in late 1936. Due to engine faults, their service ceiling was limited and they were used only in the training role, being fitted with dual controls. A total of 210 PZL.23Bs were delivered to the Air Force from 1937. They became the main armament of Polish bomber and reconnaissance “line squadrons”, in the 1930s replacing Breguet 19, Potez 25 and Potez 27 biplanes. By August 1939, there were 23 crashes, what was an average safety result.

By 1939, the aircraft was obsolescent. Its main deficiency was its low speed but a lack of manoeuvrability was also a problem (it was noted, that the maximum speed of the PZL.23B was 365 km/h, but it was forbidden to exceed 319 km/h due to dangerous flight characteristics). At the outbreak of World War II on 1 September 1939, during the invasion of Poland. Some aircraft were also used in wartime improvised units, 114 PZL.23Bs were deployed in combat units (a further 75 PZL.23B and 35 PZL.23A were in air schools, held in reserve or under repair). The PZL.23Bs were operational in five bomber squadrons (Eskadra Bombowa) of the Bomber Brigade and seven Army reconnaissance squadrons, each with 10 aircraft (other squadrons of the Bomber Brigade were equipped with PZL.37 Łoś). In addition two PZL.43A from the Bulgarian order were impressed into the Polish service in the 41st Squadron.

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On 2 September 1939, one PZL.23B of the 21st Squadron bombed a factory in Ohlau as the first bomb attack on the German territory. The PZL.23 bomber squadrons attacked German armoured columns, especially on 3 September 1939, while the main mission of Army squadrons was reconnaissance. The five squadrons of the Bomber Brigade delivered about 52-60 tons of bombs during the campaign, the Army squadrons added about a dozen tons of bombs as well.

Due to the type’s low speed, lack of armour and especially fighter protection, PZL.23s suffered high losses. Many were shot down by the German fighter aircraft, but they also shot down a few in return. Despite lack of armour, crews often attacked German columns from low level, making their aircraft vulnerable to AA fire. Some 20 aircraft crashed on rough field airfields. About 120 PZL.23s (86%) were destroyed in 1939, but only 67 due to direct enemy action. Only a small number were destroyed on airfields with the only successful Luftwaffe attack on Polish combat units on an airfield during the campaign occurring on 14 September, at Hutniki, against PZL.23Bs of the Bomber Brigade.

At least 21 PZL.23s were withdrawn in 1939 to Romania with 19 used by the Romanian Air Force against the USSR. Fifty PZL.43s and PZL.43As (two were delivered by the Germans) were used in Bulgaria for training until 1946, known as the “Chaika”. No PZL.23s were left in Poland after the war.

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Błyskawica submachine gun

The Lightning (Lightning / Flasher) was a submachine gun produced by the Home Army, or Home Army and the Polish resistance movement fighting the Germans in occupied Poland. A successful construction, it was probably the only bridge weapon designed and mass produced covertly in occupied Europe besides the Sten (British submachine gun)

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History:

In 1942 engineer Wacław Zawrotny proposed to the Armia Krajowa command that he and his colleagues prepare a project of a cheap, home-made machine pistol for use by the Polish resistance. Its main feature was its simplicity, so that the weapon could be made even in small workshops, by inexperienced engineers. The idea was accepted, and Zawrotny, together with his colleague Seweryn Wielanier, prepared a project of a sub-machine gun, soon afterward named Błyskawica (Polish for “lightning”). To allow for easier production, all parts of the weapon were joined together with screws and threads rather than bolts and welding, which were commonly used in firearm production ever since the 17th century.

The design was based on two of the most popular machine pistols of the era. The external construction with a retractable butt and magazine mounted below the gun was borrowed from the successful German MP-40. The internal design of the mechanism was modeled after the British Sten. Blow-back, with an open bolt, it offered good performance and high reliability. Unlike the British Sten (and its Polish clone called the Polski Sten) it employed a free-floating firing pin.

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The documentation was ready by April 1943, and by September a prototype was ready. After extensive tests in the forests outside of Zielonka near Warsaw, the weapon was presented to the commanding officer of the KeDyw, August Emil Fieldorf, who found the design acceptable. In November the plans were sent to a number of workshops spread throughout occupied Poland and a serial production started. The name was coined after the three lightning bolts carved on the prototype by its designers, pre-war workers of the Elektrit company that used a similar logo.
Polish soldier firing a Błyskawica during the Warsaw Uprising

The production started in a workshop officially producing metal fence nets in Warsaw. After the tests of a prototype series of five pistols, the KeDyw ordered 1000, and later an additional 300. Until July 1944 and the start of the Operation Tempest roughly 600 pieces were built in Warsaw. During the Warsaw Uprising an additional 40 were built. It is also possible that the Błyskawica was also produced in small quantities outside of Warsaw.

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Lacida

The Lacida (or LCD) was a Polish rotor cipher machine. It was designed and produced before World War II by Poland’s Cipher Bureau for prospective wartime use by Polish military higher commands.

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History:

The machine’s name derived from the surname initials of Gwido Langer, Maksymilian Ciężki and Ludomir Danilewicz and / or his younger brother, Leonard Danilewicz. It was built in Warsaw, to the Cipher Bureau’s specifications, by the AVA Radio Company.

In anticipation of war, prior to the September 1939 invasion of Poland, two LCDs were sent to France. From spring 1941, an LCD was used by the Polish Team Z at the Polish-, Spanish- and French-manned Cadix radio-intelligence and decryption center at Uzès, near France’s Mediterranean coast.

Prior to the machine’s production, it had never been subjected to rigorous decryption attempts. Now it was decided to remedy this oversight. In early July 1941, Polish cryptologists Marian Rejewski and Henryk Zygalski received LCD-enciphered messages that had earlier been transmitted to the staff of the Polish Commander-in-Chief, based in London. Breaking the first message, given to the two cryptologists on July 3, took them only a couple of hours. Further tests yielded similar results. Colonel Langer suspended the use of LCD at Cadix.

In 1974, Rejewski explained that the LCD had two serious flaws. It lacked a commutator (“plugboard”), which was one of the strong points of the German military Enigma machine. The LCD’s other weakness involved the reflector and wiring. These shortcomings did not imply that the LCD, somewhat larger than the Enigma and more complicated (e.g., it had a switch for resetting to deciphering), was easy to solve. Indeed, the likelihood of its being broken by the German E-Dienst was judged slight. Theoretically it did exist, however.

 

Mikołaj Kopernik

Nicolaus Copernicus (German: Nikolaus Kopernikus; Italian: Nicolò Copernico; English: Nicolaus Copernicus ;   19 February 1473 – 24 May 1543) was a Renaissance astronomer and the first person to formulate a comprehensive heliocentric cosmology which displaced the Earth from the center of the universe.

Born

19 February 1473
Toruń (Thorn), Royal Prussia, Kingdom of Poland

Died

24 May 1543 (aged 70)
Frombork (Frauenburg), Prince-Bishopric of Warmia, Royal Prussia, Kingdom of Poland

Fields

Mathematics, astronomy, canon law, medicine, economics

Alma mater     

Kraków University, Bologna University, University of Padua, University of Ferrara

Known for     

Heliocentrism, the Copernicus Law

 

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