sentences:  With an expected advent of a twin-engine heavy fighter, the PZL.38 Wilk, which was supposed to be a basic fighter and bomber aircraft in the Polish Air Force, there appeared the need for a twin-engine trainer aircraft for pilots.In 1936, the PWS works were ordered to build a trainer of cheap wooden construction, similar in layout to the PZL.38.The main designer was Wacław Czerwiński, known for designing several successful sailplanes.