Designed for robust use in sports and civil aviation-The PZL Wil
By Willie Bodenstein
The Polish designed PZL-104 Wilga (Golden Oriole), a short-take-off-and-landing (STOL) civil aviation utility aircraft, is designed for robust use in sports and civil aviation with a strong emphasis on glider-towing and parachute training.
Manufactured by PZL Warszawa-Okecie the good short field performer of which over 1,000 of all types have been built has become the most manufactured airplane to come from Poland. It features fixed leading edge slots and a bewildering array of engine options, from small radials to flat contemporary aero engines. The Wilga has evolved through many ever-improving versions during its continuous production from 1962 to 2006.
In most forms, a four seat aircraft, performance varies with engine, but cruise speeds are in the neighbourhood of 100 mph. Stall is an estimated 40 mph, the design is stall proof due to fixed, leading edge slats.
The prototype of the initial Wilga Mark 1 variant was first flown on 24 April 1962 powered by the PZL WN-6RB 220 hp (160 kW) horizontally-opposed engine. The Wilga 1 prototype exposed a number of design faults which was addressed in the Mark 2 variant that had its first flight on 1 August 1963.
Featuring a completely new slimmer, strengthened fuselage that also offered an excellent rear view aspect for the crew during glider towing operations and with re-engineered side doors that opened upwards for better aero observation or parachute jump sorties the upgraded Wilga 2 could be flown with the doors open if required.
Although the Wilga 2 airframe had proved a successful design its engine was not fully developed and so it did not enter serial production. The Mark 3 was fitted with the more powerful 260 hp (190 kW) Ivchenko AI-14R Radial. Even though he radial spoiled the previously clean and aerodynamic fuselage lines the new variant was successful. The combination and the STOL capability of the airframe resulted in an extraordinary high rate of climb of 11 m/s (2,165 fpm) (maximum) under minimal load.
Wilga's served in the defence forces of eleven countries as well as with numerous civilian operators world-wide. In Poland, they form the backbone contingent of the Polish Aero Club where they are the basic aircraft used in flight training. From 1978 to 2006 Polish pilots flying Wilgas have won numerous prizes in the FAI World Rally Flying and Precision Flying Championships. In military service they are used as liaison, recovery and light observation platforms.