 The first prototype was completed in October 1933, with a 265 hp Menasco inline engine, and first flew on December 4, 1933.In January 1934 it was fitted with Czech Walter Bora radial engine (220 hp), and in spring 1934 with newly constructed Polish radial engine GR-760 (290 hp), created by Stanisław Nowkuński.In 1934 there were built 8 RWD 9s