PZL-104 Wilga

PZL-104 Wilga
PZL-104 Wilga 35
Role	Utility aircraft
National origin	Poland
Manufacturer	PZL Warszawa-Okęcie
First flight	24 April 1962
Status	Production Ended
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 from 1962 to 2006, when the European Aeronautic Defence and Space Company (EADS) announced on their website the production of this aircraft would cease.

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 24 April 1962 powered by an existing Polish 220 hp (160 kW) 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.

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, and the side doors were re-engineered to open upwards for 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 PZL-104 Wilga Mark 2 variant first flew on 1 August 1963, followed by a short production run which later was converted to the Wilga C and Wilga Mark 3 configurations. On 30 December 1963 the Wilga C (or Wilga Mark 2 Subvariant C) was flown, an export variant for Indonesia powered by the imported North American -certified 225 hp (168 kW) horizontally-opposed Continental O-470 engine. 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 (190 kW) 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 of 11 m/s (2,165 fpm) (maximum) under minimal load was possible. One of a few remaining flaws was a relatively uneconomical engine.

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Wikipedia