PZL MD-12
Encyclopedia
The PZL
MD-12 was a Polish
four-engined short-range passenger and civil utility aircraft of the 1960s, which remained in a prototype stage.
on short domestic routes for LOT Polish Airlines
. The plane was designed by a design bureau led by Franciszek Misztal
in the Aviation Institute (Instytut Lotnictwa). The first design work started in 1954 (under the designation FM-12) and the final design MD-12 appeared in 1956, after Leszek Dulęba had joined (the designation apparently came from Misztal-Dulęba). Initially it was to be powered with two Soviet 615 hp ASh-21 engines, but because their production stopped, a four-engine configuration was chosen, with Polish 315 hp WN-3 engines. In December 1957
the bureau was moved to the OKL centre (Ośrodek Konstrukcji Lotniczych - Aviation Designs' Centre), created in the WSK-Okęcie
factory.
The first prototype flew first on 21 July 1959 (registration SP-PAL), the second prototype, designated MD-12P (SP-PBD), and fitted with complete passenger cab, on 7 January 1961. There was a third airframe built for static trials. The plane underwent state trials in 1961, and the second prototype was evaluated by LOT Airlines in August-September 1961.
The passenger variant was evaluated as quite successful, being easier to fly, than the Ilyushin Il-14
and more economical, but it was not produced because LOT found it unprofitable to order special planes for domestic routes. The small production that would result would increase costs. Instead, less modern airliners were switched from international to domestic routes.
It was next decided to build an aerial photography
variant MD-12F. It was fitted with several cameras and other equipment, including a darkroom. The fuselage nose was glazed, with a navigator post. Span increased to 23.6 m by adding longer wingtips. The MD-12F flew first on 21 July 1962 (apparently dates of MD-12 prototypes' flights were adjusted to add splendour to communist Poland's national holiday, 22 July). It carried the registration SP-PBL. The aerial photography variant was successful and countries, like the USSR, Hungary, Romania and Pakistan were interested in it, but its development was ceased along with a crash of the first MD-12 prototype on 17 September 1963 near Grójec
. The plane crashed due to flutter of tail control surfaces and a crew of 5 were killed.
in August-September 1961, on Warsaw-Rzeszów
route, carrying over 1700 persons. It was also used in 1961 and 1962 on Warsaw-Poznań
route, taking trips to Poznań International Fair
.
of all-metal construction, duralumin
-covered. The fuselage was a semi-monocoque
. The crew cockpit in front with a crew of two pilots. Passenger cab with 20 seats in three rows. In the rear there was WC. Fuselage had doors in front part. In a fuselage nose there was a baggage space for 200 kg. Trapezoid three-part wing. Single tailfin. Engine nacelles in wings. Two-blade wooden propellers WR-1A of a variable pitch, diameter 2.2 m (powerplants were adapted from the TS-8 Bies trainer). Retractable tricycle landing gear - main gear with single wheels retractable to inner engine nacelles. Fuel tanks 1160 l in wings (cruise fuel consumption 240 l/h).
MD-12P
MD-12F
PZL
PZL was the main Polish aerospace manufacturer of the interwar period, based in Warsaw, functioning in 1928-1939...
MD-12 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...
four-engined short-range passenger and civil utility aircraft of the 1960s, which remained in a prototype stage.
Design and development
The aircraft was development as a successor to the Lisunov Li-2Lisunov Li-2
The Lisunov Li-2, originally designated PS-84 , was a license-built version of the Douglas DC-3. It was produced by the GAZ-84 works at Moscow-Khimki, and subsequently at GAZ-33 at Tashkent-Vostochn. The project was directed by aeronautical engineer Boris Pavlovich Lisunov.-Design and...
on short domestic routes for LOT Polish Airlines
LOT Polish Airlines
Polskie Linie Lotnicze LOT S.A. , trading as LOT Polish Airlines, is the flag carrier of Poland. Based in Warsaw, LOT was established in 1929, making it one of the world's oldest airlines still in operation. Using a fleet of 55 aircraft, LOT operates a complex network to 60 destinations in Europe,...
. The plane was designed by a design bureau led by Franciszek Misztal
Franciszek Misztal
Franciszek Misztal - Polish aircraft designer.He studied at Lviv Polytechnic and received his doctorate in 1929 at the Technical University in Aachen. From 1928 he worked in the PZL in Warsaw as a constructor...
in the Aviation Institute (Instytut Lotnictwa). The first design work started in 1954 (under the designation FM-12) and the final design MD-12 appeared in 1956, after Leszek Dulęba had joined (the designation apparently came from Misztal-Dulęba). Initially it was to be powered with two Soviet 615 hp ASh-21 engines, but because their production stopped, a four-engine configuration was chosen, with Polish 315 hp WN-3 engines. In December 1957
1957 in aviation
This is a list of aviation-related events from 1957:- Events :* The Douglas AIR-2 Genie unguided air-to-air missile enters service with the United States Air Force...
the bureau was moved to the OKL centre (Ośrodek Konstrukcji Lotniczych - Aviation Designs' Centre), created in the WSK-Okęcie
PZL
PZL was the main Polish aerospace manufacturer of the interwar period, based in Warsaw, functioning in 1928-1939...
factory.
The first prototype flew first on 21 July 1959 (registration SP-PAL), the second prototype, designated MD-12P (SP-PBD), and fitted with complete passenger cab, on 7 January 1961. There was a third airframe built for static trials. The plane underwent state trials in 1961, and the second prototype was evaluated by LOT Airlines in August-September 1961.
Ilyushin Il-14
The Ilyushin Il-14 was a Soviet twin-engine commercial and military personnel and cargo transport aircraft that first flew in 1950, and entered service in 1954. Il-14 was also manufactured in East Germany by VVB Flugzeugbau, in Czechoslovakia as the Avia 14, and in China under the Chinese...
and more economical, but it was not produced because LOT found it unprofitable to order special planes for domestic routes. The small production that would result would increase costs. Instead, less modern airliners were switched from international to domestic routes.
It was next decided to build an aerial photography
Aerial photography
Aerial photography is the taking of photographs of the ground from an elevated position. The term usually refers to images in which the camera is not supported by a ground-based structure. Cameras may be hand held or mounted, and photographs may be taken by a photographer, triggered remotely or...
variant MD-12F. It was fitted with several cameras and other equipment, including a darkroom. The fuselage nose was glazed, with a navigator post. Span increased to 23.6 m by adding longer wingtips. The MD-12F flew first on 21 July 1962 (apparently dates of MD-12 prototypes' flights were adjusted to add splendour to communist Poland's national holiday, 22 July). It carried the registration SP-PBL. The aerial photography variant was successful and countries, like the USSR, Hungary, Romania and Pakistan were interested in it, but its development was ceased along with a crash of the first MD-12 prototype on 17 September 1963 near Grójec
Grójec
Grójec is a town in Poland. Located in the Masovian Voivodeship, about 40 km south of Warsaw, it is the capital of Grójec County. It has about 14,875 inhabitants . Grójec surroundings are considered to be the biggest apple-growing area of Poland. It is said, that the region makes up also for...
. The plane crashed due to flutter of tail control surfaces and a crew of 5 were killed.
Operational service
The prototype MD-12P (SP-PBD) was evaluated by the LOT Polish AirlinesLOT Polish Airlines
Polskie Linie Lotnicze LOT S.A. , trading as LOT Polish Airlines, is the flag carrier of Poland. Based in Warsaw, LOT was established in 1929, making it one of the world's oldest airlines still in operation. Using a fleet of 55 aircraft, LOT operates a complex network to 60 destinations in Europe,...
in August-September 1961, on Warsaw-Rzeszów
Rzeszów
Rzeszów is a city in southeastern Poland with a population of 179,455 in 2010. It is located on both sides of the Wisłok River, in the heartland of the Sandomierska Valley...
route, carrying over 1700 persons. It was also used in 1961 and 1962 on Warsaw-Poznań
Poznan
Poznań is a city on the Warta river in west-central Poland, with a population of 556,022 in June 2009. It is among the oldest cities in Poland, and was one of the most important centres in the early Polish state, whose first rulers were buried at Poznań's cathedral. It is sometimes claimed to be...
route, taking trips to Poznań International Fair
Poznan International Fair
The Poznań International Fair is the biggest industrial fair in Poland. It is held on the Poznań fairground in Poland. Poznań International Fair is located in the centre of the city opposite the main railway station - Poznań Główny, in the centre of Poland and in the centre of...
.
Design
The MD-12 was a four-engined low-wing cantilever monoplaneMonoplane
A monoplane is a fixed-wing aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...
of all-metal construction, duralumin
Duralumin
Duralumin is the trade name of one of the earliest types of age-hardenable aluminium alloys. The main alloying constituents are copper, manganese, and magnesium. A commonly used modern equivalent of this alloy type is AA2024, which contains 4.4% copper, 1.5% magnesium, 0.6% manganese and 93.5%...
-covered. The fuselage was a semi-monocoque
Monocoque
Monocoque is a construction technique that supports structural load by using an object's external skin, as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin or coachwork...
. The crew cockpit in front with a crew of two pilots. Passenger cab with 20 seats in three rows. In the rear there was WC. Fuselage had doors in front part. In a fuselage nose there was a baggage space for 200 kg. Trapezoid three-part wing. Single tailfin. Engine nacelles in wings. Two-blade wooden propellers WR-1A of a variable pitch, diameter 2.2 m (powerplants were adapted from the TS-8 Bies trainer). Retractable tricycle landing gear - main gear with single wheels retractable to inner engine nacelles. Fuel tanks 1160 l in wings (cruise fuel consumption 240 l/h).
Variants
MD-12- Prototype. One built, registered as SP-PAL.
MD-12P
- Passenger version. One built, registered as SP-PBD.
MD-12F
- Aerial photography version with glazed nose and increased wing span. One built, registered as SP-PBL.