 The single-seaters featured an aerodynamic fairing that slid on and off to provide access to the pilot's seat.The two-seaters, however, had a permanently fixed cockpit pod that seated the pilot and instructor in tandem, open cockpits, each with a small windscreen The rear cockpit was located directly beneath the wing and was accessed via a door on the port side of the gondola.Apart from the change in gondola, all other components remained interchangeable with the Ps-2

In each case, the "s" stands for "serii" (серии – "series")

"Uchebnyi" (Учебный – "Trainer")