The CSS-12 was a prototype Polish twin-engined

feederliner A regional airliner, commuter airliner or feeder liner is a small airliner that is designed to fly up to 100 passengers on short-haul flights, usually feeding larger carriers' airline hubs from small markets. This class of airliners is typicall ...

of the 1950s. A single example was built and flown in 1950, but no production followed.

Design and development

The

German invasion of Poland The invasion of Poland, also known as the September Campaign, Polish Campaign, and Polish Defensive War of 1939 (1 September – 6 October 1939), was a joint attack on the Second Polish Republic, Republic of Poland by Nazi Germany, the Slovak R ...

at the start of the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

resulted in the destruction of Poland's aviation industry, and following the end of the war the Polish government decided to re-establish a national aviation industry. Two design bureaus were set up to design and develop prototypes, ''

Lotnicze Warsztaty Doświadczalne ''Lotnicze Warsztaty Doświadczalne'' (LWD) was the Polish aerospace manufacturer and construction bureau, located in Łódź, active between 1945 and 1950. The name meant Aircraft Experimental Workshops. It was the first Polish post-war aerosp ...

'' (LWD) (Aircraft Experimental Workshops) at

Łódź Łódź is a city in central Poland and a former industrial centre. It is the capital of Łódź Voivodeship, and is located south-west of Warsaw. Łódź has a population of 655,279, making it the country's List of cities and towns in Polan ...

and the '' Centralne Studium Samolotów'' (C.S.S.) (Central Aircraft Study) based at

Warsaw Warsaw, officially the Capital City of Warsaw, is the capital and List of cities and towns in Poland, largest city of Poland. The metropolis stands on the Vistula, River Vistula in east-central Poland. Its population is officially estimated at ...

, with production to be carried out at a series of State Aircraft Factories (

PZL PZL, may refer to: Places * PZL, an IATA airport code for Phinda Airfield in KwaZulu-Natal, South Africa * PZL, a location code for the Złotów County, Greater Poland Voivodeship, Poland, in the system of the vehicle registration plates of Polan ...

).Cynk ''Flight'' 16 November 1956, p. 779.Bridgman 1956, p. 193. The C.S.S., led by Franciszek Misztal, who worked as a designer in the pre-war

, was tasked with the design of three types, the CSS-10, a single-engined

primary trainer A trainer is a class of aircraft designed specifically to facilitate flight training of pilots and aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem flight controls, forgiving flight characteristic ...

, an aerobatic trainer, the CSS-11 and a twin-engined

, which was designated CSS-12.Cynk ''Flight'' 16 November 1956, p. 780. Work on the CSS-12 began in 1948, with the prototype making its maiden flight on 22 November 1950. It was a twin-engined low-wing

cantilever A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilev ...

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

of all-metal construction,Bridgman 1956, p. 194. the first all-metal aircraft to be built in Poland following the end of the Second World War. The oval section fuselage accommodated seats for ten passengers in two rows of five, with the two pilots sitting in an enclosed flight deck forward of the passenger cabin, while a cloakroom and baggage compartment aft of the cabin. The aircraft's wings featured a mixture of smooth and corrugated

duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium–copper alloys. The term is a combination of ''Düren'' and ''aluminium'' ...

skinning, with the corrugated sections covered in fabric to reduce drag. Full-span hydraulically operated trailing-edge flaps were fitted, while engine exhaust gas was used to de-ice the wings' leading edge. The aircraft was fitted with a retractable nosewheel undercarriage. Two

Argus As 411 The Argus 411 was an air-cooled, inverted-V12 aircraft engine developed by Argus Motoren in Germany during World War II. Design and development The As 411 was a refined and more powerful version of the Argus As 410. Most 411 production was under ...

engines, built in Germany during the war, drove two-bladed

constant speed propeller Constant or The Constant may refer to: Mathematics * Constant (mathematics), a non-varying value * Mathematical constant, a special number that arises naturally in mathematics, such as or Other concepts * Control variable or scientific con ...

s. At the end of 1950, the Polish aviation industry was re-organised, with large orders being placed for license-production of Soviet Mikoyan–Gurevich MiG-15 jet fighters. As part of this reorganisation, LWD and the CSS were disbanded, and work on the CSS-12 was suspended.Cynk ''Flight'' 23 November 1956, p. 814. In 1955 flight testing of the CSS-12 resumed. Although testing was successful, with the aircraft setting an international class altitude record of while carrying a payload of on 27 December 1957, no production followed, as the CSS-12 did not meet the requirements of Poland's national airline LOT and no suitable replacements for its out-of production German engines were available. Instead, the CSS-12 formed the basis of the larger four-engined

PZL MD-12 The MD-12 is a Polish four-engined short-range passenger and civil utility aircraft of the 1960s, which remained in the prototype stage. The PZL brand is conventional, since it did not enter production, and was referred to under its project desig ...

airliner which made its first flight in 1959.Taylor 1961, p. 118.

Specifications

Notes

References

* * * * {{PZL aircraft 1950s Polish airliners Twin piston-engined tractor aircraft Low-wing aircraft Aircraft first flown in 1950