| 词条 | PWS-21 | ||||||||||||||||
| 释义 |
The PWS-21 was a Polish passenger aircraft for 4 passengers, built in PWS factory in 1930, that remained a prototype. DevelopmentThe aircraft was developed for a contest for a successor of Junkers F-13 in LOT Polish Airlines. The first design of 1929, named PWS-21, developed by Stanisław Cywiński and Jarosław Naleszkiewicz, was a braced high-wing plane, but it was not realized because LOT demanded bigger passenger cab. The next design, named PWS-21bis, was a cantilever high-wing plane, similar to Fokker F.VIIa/1m design. The only prototype (markings SP-AEC) first flew in the spring, probably April of 1930 in Biała Podlaska. Its counterpart was Lublin R-XI. The plane appeared not successful. It was too heavy, what resulted in poor speed, ceiling and range, and long take off. In 1931 it was evaluated in LOT airlines, but after a test flight it was returned to the factory. However, at that time there was its development, PWS-24 built, sharing the same lightweight wing, which was ordered by LOT. Description (PWS-21bis)High-wing cantilever monoplane of mixed construction, with closed cab and single engine. A fuselage made of a steel frame, covered with canvas. Straight one-piece wooden wing, with elliptical endings, plywood covered, two-spar. Crew of two (pilot and mechanic), in a cabin before the wing, with twin controls. The cabin had a vertical front windshield and doors on both sides. Next and slightly below in a fuselage, under the wing, there was a cabin for 4 passengers, with a door on the left. The cabin had a toilet. The fifth passenger could be taken instead of the mechanic. 9 cylinder radial engine Skoda Wright Whirlwind J-5 (240 hp take-off power, 220 hp nominal power) in the fuselage front, fitted with a Townend ring. Two-blade metal propeller of a fixed pitch. Conventional landing gear, with a rear skid; struts with shock absorbers joined the main gear with wings. Fuel tanks 250 l in central wing section. Specifications (PWS-21bis){{aircraft specifications||plane or copter?=plane |jet or prop?=prop |crew=2, pilot and mechanic |capacity=4 (max 5 instead of the mechanic) |length main= 9.44 m |length alt= |span main=15 m |span alt= |height main=2.9 m |height alt= |area main=31.75 m² |area alt= ft² |airfoil= |empty weight main= 1317 kg |empty weight alt= |loaded weight main= 2000 kg |loaded weight alt= |useful load main= 683 kg |useful load alt= |max takeoff weight main= |max takeoff weight alt= |engine (prop)=Skoda Wright Whirlwind J-5 |type of prop= air-cooled 9-cylinder radial |number of props=1 |power main=240 hp |power alt= |max speed main=167 km/h |max speed alt= |cruise speed main= 140 km/h |cruise speed alt= |stall speed main= <93 km/h |stall speed alt= |range main=600 km |range alt= |ceiling main=1,300 m |ceiling alt= |climb rate main= 1.3 m/s |climb rate alt= |loading main= 63.2 kg/m² |loading alt= |power/mass main= |power/mass alt= |armament= }} See also{{aircontent||related=
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External links{{commons category|PWS}}
5 : Polish airliners 1930–1939|PWS aircraft|Single-engined tractor aircraft|High-wing aircraft|Aircraft first flown in 1930 |
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