Szpak-2 and Szpak-3 remained in single units, but in 1947 there was designed the LWD Szpak-4, which was the first Polish post-war plane built in series - a short series of 10 was manufactured in PZL-Mielec.
Szpak-2 and Szpak-3 continued as individual units, but in 1947, the LWD Szpak-4 was designed, which marked the first Polish post-war aircraft produced in large numbers - a limited series of 10 was manufactured at PZL-Mielec.