PZL
PZL (Państwowe Zakłady Lotnicze - State Aviation Works) was the main Polish aerospace manufacturer of the interwar period, based in Warsaw, functioning in 1928-1939. The abbreviation was thereafter - from late 1950s - used as an aircraft brand and as a part of names of several Polish state-owned aerospace manufacturers referring to traditions of the PZL, belonging to the Zjednoczenie Przemysłu Lotniczego i Silnikowego PZL - PZL Aircraft and Engine Industry Union. After the fall of communism in Poland in 1989, these manufacturers became separate plants, still sharing the PZL name. In the case of PZL Mielec, the abbreviation was later developed as Polskie Zakłady Lotnicze - Polish Aviation Works.
PZL (1928-1939)
PZL-230 Skorpion
The PZL-230 Skorpion was a design for a Polish Air Force attack aircraft. The project was started in the late 1980s by the PZL (Polish State Aviation Works) and cancelled in 1994 due to a lack of funds. Skorpion would have had twin jet engines, a fuselage afterbody blending into the wing and small canards behind the cockpit.
History
The project was developed by a team under Andrzej Frydrychewicz at PZL Okęcie, analyzing the experiences of modern wars, such as that in Vietnam and the Soviet war in Afghanistan and capitalizing on their experience with other recent Polish designs like the Orlik. Among the desired capabilities were Short Take-Off and Landing (STOL) and maneuverability but with armored protection. It had to be cheap, easy to build and modify (due to its modular design). The early variant incorporated a single pilot, twin jet engines mounted on the upper fuselage like the A-10 Thunderbolt II and canard-type construction. It also required an ability to take-off and land on a runway of about 250 m in length, travel at speeds of up to 640 km/h, be armed with a 25 mm cannon and be able to carry up to 2,000 kg of both Warsaw Pact and NATO munitions. Composites, fly-by-wire and other advanced avionics were also to be used in its construction.
PZL.46 Sum
PZL.46 Sum was a projected light bomber of the Polish Air Force before World War II, which did not proceed beyond prototype stage.
Design and development
The PZL.46 Sum (wels catfish) was designed by Stanisław Prauss in the PZL works as a successor to the standard Polish light bomber and reconnaissance plane, the PZL.23 Karaś, also of Prauss' design. First sketches were made in 1936. In order to test new features, like double tail fins and a retractable underbelly bombardier gondola, a single modified PZL.23, designated PZL.42 was built and tested in 1936.
The first prototype of PZL.46 Sum flew in August 1938. It shared only a general composition with Karaś, its fuselage was much more aerodynamically refined and its wings had thinner profile. Initially it was intended to use retractable landing gear, but since the Polish industry did not produce retractable landing gear, a fixed one was used. In November–December 1938 the prototype was shown at the Paris Air Show. In May 1939 the second similar prototype was flown (PZL.46/II).
P.Z.L. 27
The P.Z.L. 27 was a prototype airliner/mail-plane designed by Zbysław Ciołkosz and constructed at P.Z.L. in 1933.
Design and development
Ordered by the Polish Ministry of Transport as a fast mail-plane, the prototype flew for the first time in September 1933 and was the first P.Z.L. aircraft with a retractable undercarriage. Several tests made at the Institute of Aviation in 1935-1936 showed that the plane had poor performance and was uneconomical to operate.
Technical design
Construction of the P.Z.L. 27 consisted of a welded steel tube fuselage and tail-unit covered with fabric and a wooden 2-spar wing. Three 130 hp (97 kW) de Havilland Gipsy Major I engines were fitted, one in the nose and two in strut-mounted nacelles under the high-set wings. The retractable main undercarriage members retracted manually into the rear of the engine nacelles, with a non-retractable tail-skid at the extreme rear of the fuselage.
Operational history
After initial flight testing the prototype P.Z.L. 27 the aircraft was returned to P.Z.L. to have a revised wing fitted to alleviate problems with insufficient stiffness and poor lateral stability. After a second phase of testing a Certificate of Airworthiness was issued and the aircraft was equipped for use as an airliner, being delivered to P.L.L. (LOT). LOT used the aircraft for proving flights on mail routes but regarded it as obsolete, refusing to order production aircraft. The RWD 11, designed in competition with the P.Z.L. 27, was regarded as superior but this aircraft also failed to attract production orders.
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