| PZL.4 | |
|---|---|
 | |
| Role | Passenger aircraft |
| Manufacturer | PZL |
| First flight | 8 January 1932 |
| Introduction | 1933 |
| Retired | 1936 |
| Status | prototype |
| Primary user | Polish civilian aviation (LOT Polish Airlines) |
| Number built | 1 |
The PZL.4 was a Polish three-engine passenger aircraft for 10 passengers, built in PZL factory in 1932, which remained a prototype. It was the first Polish-designed and produced multi-engine plane.
Despite purchasing a number of three-engine Fokker F.VIIb/3m aircraft, LOT Polish Airlines soon started looking for a more modern design and organized a design contest in 1928. The contest was won by the Polish engineer Zygmunt Bruner, working in the French Bernard works, with his design T-600. It was an all-metal high-wing three-engine monoplane, similar to Ford Trimotor. State Aviation Works PZL decided to take over its development, and a group of engineers was sent to Paris and worked the design in 1929, under direction of Zygmunt Bruner. There were also carried out aerodynamic trials of a plane model. Detailed technical drawings were worked in PZL in Warsaw in 1930, under direction of Stanisław Prauss, and a prototype was built, designated PZL.4 (this designation was used before for a single-engine design worked out for a passenger plane contest in 1928, won by PWS-20).
The PZL.4 was a high-wing cantilever monoplane of metal construction, with closed cab and three engines. The fuselage was rectangular in cross-section, made of duralumin and covered with duralumin sheet. The two-spar wings and tailfins were covered with Wibault-pattern ribbed duralumin sheet. The wings had squared-off wingtips. A crew of two (pilot and mechanic), were accommodated in front, before the wing, equipped with twin controls. Behind and slightly below under the wing, there was a cabin for 10 passengers in three compartments in the fuselage. The cabin had wide rectangular windows, sloped outwards for a better view, and door on the left side. The cabin had places for a baggage behind it and below a floor.
Three 9-cylinder Polish-Skoda J-5a Whirlwind radial engines mounted in the fuselage nose and in wing nacelles provided (180 kW (240 hp) takeoff power and 160 kW (220 hp) nominal power. The engines were fitted with Townend rings and three-blade metal propellers, later two-blade wooden propellers of a fixed pitch. A conventional fixed landing gear, with a rear wheel, main gear wheels' diameter 1.15 m (3 ft 9 in) was also fitted. The fuel tank capacity of 915 L (242 US gal; 201 imp gal) in wing centre-section tanks, providing (cruise fuel consumption 180 L/h (48 gal/h; 40 imp gal/h)).
The prototype was first flown on 8 January 1932 in Warsaw by Bolesław Orliński (markings SP-AGY). In June 1932 it took part in an international air meeting in Warsaw. From autumn 1932 to 1935 it was evaluated by LOT Polish Airlines, but it was found unsatisfactory. The empty weight was larger by 730 kg, over the design specification, which decreased performance. As a result, its performance was inferior to Fokker F.VIIb/3m, with the same engines. Proposals to use 220 kW (300 hp) Gnome-Rhône 7K or 340 kW (450 hp) Pratt & Whitney R-1340 Wasp engines were rejected by LOT (the latter engines would demand strengthening of construction).
The prototype cost was 1,416,110 złoty and it brought the manufacturer 663,000 złoty loss. [1] The prototype was withdrawn from service in 1936 and scrapped in 1937.
Data from Polish Aircraft 1893–1939 [2]
General characteristics
Performance
The PZL.23 Karaś was a Polish light bomber and reconnaissance aircraft designed in the early 1930s by PZL in Warsaw.
The PZL P.7 was a Polish gull wing monoplane fighter aircraft designed in the early 1930s at the PZL factory in Warsaw. It was the main fighter of the Polish Air Force between 1933 and 1935. The PZL P.7 was replaced in Polish service by its follow-up design, the PZL P.11c. More than 30 PZL P.7 fighters remained in service during the Invasion of Poland, scoring several kills despite its obsolescence.
The PWS-24 was a Polish single-engine passenger aircraft for 4 passengers, built in PWS factory, used from 1933 to 1936 by LOT Polish Airlines. In spite of its limited capacity, it was the only series-built airliner of domestic design ever used by the LOT.
The PWS-33 Wyżeł was a Polish twin-engined military trainer aircraft from a period before World War II constructed by Podlaska Wytwórnia Samolotów or PWS. Although destined for production it got no further than the prototypes before Poland was invaded.
PZL.19 was a Polish sports aircraft built in 1932 in the PZL works. Ordered by the Ministry of Communications, it was specifically designed for the upcoming Challenge 1932 contest held that year in Germany.
The PZL.44 Wicher (gale) was a prototype of 14-seat, twin-engine Polish airliner, built in the Państwowe Zakłady Lotnicze (PZL) in 1938. It was to compete with the DC-2 and Lockheed Super Electra.
The PZL P.6 was a Polish fighter, designed by the engineer Zygmunt Puławski, manufactured by PZL state-owned factory. It remained a prototype.
PZL.26 was a Polish sports plane built in 1934 in the PZL works. Ordered by the Ministry of Defence, it was specifically designed for the upcoming Challenge 1934 International Touring Aircraft Contest.
The PZL M-24 Dromader Super is a single engine agricultural aircraft, developed in the 1980s by the WSK-Mielec from the PZL-Mielec M-18 Dromader. It did not progress beyond the prototyping stage.
The Lublin R-X was a Polish single-engined, two seat liaison aircraft, built in 1929 in the Plage i Laśkiewicz factory in Lublin. Seven were completed, two of them prototypes. Four served with Polish air regiments and another made several notable long flights and tours.
The Lublin R-XVI was a Polish passenger and air ambulance aircraft, designed in the 1930s in the Plage i Laśkiewicz factory in Lublin and built in a small series.
The Lublin R-XX was the Polish torpedo bomber floatplane, designed in the early 1930s in the Plage i Laśkiewicz factory in Lublin. It remained a prototype.
PZL.12 (PZL-H) was a prototype of a Polish amphibious flying boat designed and built in 1931 by Zygmunt Puławski, a pioneering Polish designer. He was killed in a crash involving this design.
The PZL.16 was a Polish passenger aircraft, designed in the early 1930s in the PZL in Warsaw. It remained a prototype.
The PZL Ł.2 was the Polish Army cooperation and liaison aircraft, built in 1929 in the Polskie Zakłady Lotnicze (PZL) in Warsaw. Only a small series of 31 aircraft, including prototype, were made, and used by the Polish Air Force in the 1930s. The aircraft was known in Poland for accomplishing of a long-distance tour around Africa in 1931.
The Bartel BM 6 was a Polish biplane trainer fighter aircraft of 1930. It did not advance beyond the prototype stage.
The PZL P.1 was a Polish fighter, designed by the engineer Zygmunt Puławski, manufactured by the PZL state-owned factory. It remained a prototype, but it was the first of the Polish PZL gull wing fighter series, leading to the PZL P.7, PZL P.11 and PZL P.24.
The PWS-20 was a Polish single-engine high-wing 8 passenger airliner, built in the PWS factory and when it made its first flight in 1929 it became the first Polish-designed transport aircraft to fly.
The PZL M-17 "Duduś Kudłacz" was a Polish twin-boom pusher general aviation and trainer aircraft of 1977, which remained a prototype.
The Lublin R-XI was the Polish passenger plane for 4 passengers, designed in 1930 in the Plage i Laśkiewicz factory in Lublin, that remained a prototype.
Aircraft of comparable role, configuration, and era
