| PZL-104 Wilga | |
|---|---|
| PZL-104 Wilga 35 | |
| Role | Utility aircraft |
| Manufacturer | PZL Warszawa-Okęcie |
| First flight | 24 April 1962 |
| Status | in production |
| Primary user | Polish military and civilian aviation |
| Produced | 1962-2006 |
| Number built | 1000+ |
PZL-104 Wilga (Golden Oriole) is a Polish designed and built short-takeoff-and-landing (STOL) Civil Aviation utility aircraft manufactured by PZL "Warszawa-Okęcie";. The Wilga has evolved through many ever-improving versions during its continuous production run from 1962 to 2006, when EADS announced on their website that they decided to stop the production of this aircraft.
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The PZL-104 was designed for robust use in sports, civil aviation, with a strong emphasis on glider-towing and parachute training. The prototype of the initial Wilga Mark 1 variant was first flown on April 24 1962 and was engined with an existing Polish 220 hp horizontally-opposed engine the PZL WN-6RB. The Wilga 1 prototype exposed a number of design faults, the most serious of which was excessive weight and a rear view restriction such that the crew could not easily see a towed glider. This resulted in an airframe review that thoroughly redesigned the aircraft, led by Bronisław Żurakowski and Andrzej Frydrychewicz.
They started by retaining major structural elements and successful sub-assemblies from the wings in the initial design. A completely new slimmer, strengthened fuselage was added that also offered an excellent rear view aspect for the crew during glider towing operations. The side doors were re-engineered to open upwards for a better aero observation or parachute jump sorties. The upgraded aircraft could be flown with the doors open if required, and had an air ambulance conversion capability.
The new variant, PZL-104 Wilga Mark 2, flew first on 1 August 1963 followed by a short production run which (later was converted to the Wilga C and Wilga mark 3 configurations). On December 30, 1963 the Wilga C (or Wilga Mark 2 Subvariant C), an export variant for Indonesia, was flown, powered by an imported North American certified 225 hp horizontally opposed engine the Continental O-470. The Wilga 2 airframe had proved a successful design, but the WN-6RB engine was not fully developed and so did not enter serial production. As a result, it was decided to use an in production radial engine, the 260 hp Ivchenko AI-14R; and this led to the PZL-104 Wilga Mark 3 variant, which first flew on 31 December 1965. The new engine was more powerful, but it spoilt the previously clean and aerodynamic fuselage lines, originally designed for a flat engine; nonetheless, the new variant was successful. Due in combination to the power of the engine and the STOL capability of the airframe, an extraordinary high rate of climb - maximum 11 m/s (2,165 fpm) under minimal load was possible. One of a few remaining flaws was a relatively uneconomical engine.
Another variant, the Wilga 32, was an improved small series export variant with a Continental flat engine, produced also in Indonesia as the "Gelatik". After producing 13 Wilga 3s, there were some improvements made, most notably a landing gear base increased from 2.12 m to 2.83 m to improve stability. An improved model, designated PZL-104 Wilga 35, first flew on 29 June 1967, subsequently entering mass production. The most numerous variant of Wilga 35 was the utility plane Wilga 35A, others were built in small numbers or remained prototypes.
From 1979 the Wilga 80 went into production, an improved model certified for the US market. In the late 1990s the PZL-104MA Wilga 2000 [1] family was developed with Lycoming flat engines and with improved aerodynamics.
Over 1000 Wilgas of all types have been built, including 935 of the Wilga 35 and 80, making the PZL-104 the highest volume production run of any Polish aircraft design. A Canadian aircraft supplier even considered building the Wilga aircraft for the Air Cadet league due to its complete compliance with glider training requirements, and the need for more aircraft, but were unable to get the full support of EADS to further produce the PZL-104MA Wilga 2000.[2]
With an all aluminium construction the Wilga is a high-wing cantilever STOL monoplane, with a conventional layout. The main cabin is constructed of duralumin, riveted and corrugated, increasing the strength and durability of the low mass semi-monocoque fuselage. The rectangular single-spar wing is fitted with slotted flaps and anti-stall slats. The four-seat cabin is fitted with two large side doors, opening upwards to facilitate large load, rapid entry/exit. The main wheels are attached to an articulated, conventional fixed pneumatic shock landing gear with a heavy duty sprung tail wheel and glider tow hook. The two-bladed composite wooden propeller is strengthened with bonded metal leading edges. The Soviet-built engine rotates in an opposite direction to North American standards. The newest models of Wilgas use full metal propellers and North American Continental O-470 engines with standard rotation. Likewise, presently two fuel tanks (195 L/42.9 Imperial Gal, which is equal to 51.5 US Gal) are located in the wings.
Wilgas are used in civil aviation for touring, observation, glider towing, parachute training, and bush flying. In Poland, they form the backbone contingent of the Polish Aero Club where they are the basic aircraft used in flight training. Polish pilots flying Wilgas have won numerous prizes in the FAI World Rally Flying and Precision Flying Championships, from 1978 to 2006. In military service they are used as liaison, recovery and light observation platforms.
Data from [3]
General characteristics
Performance
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