the pws-12 was a single-engined two-seat training biplane, fit also for aerobatics, designed in 1928 by a. grzędzielewski and august bobek-zdaniewski at the pws factory. the design shared similar parts, including fuselage and engine, as a high-wing trainer fighter plane pws-11, developed at the same time. the main difference was the addition of a lower wing. it was powered by a nose-mounted skoda-built version of the wright j-5 whirlwind radial engine. two prototypes and an airframe for static tests were ordered by the aviation department of the war ministry in february 1928 (along with the pws-11 prototypes). the first prototype was flown by franciszek rutkowski in november 1929. it was later improved - among others, a townend ring replaced naca cowling, and it was fitted with n-shaped struts between wings instead of perpendicular struts. the second improved prototype was flown on 18 november 1930, and designated pws-12bis. testing was successful and a production order for 20 aircraft was placed by the polish air force.