in 1923 a design bureau was established at the plant, headed by nikolai nikolaevich polikarpov; this would later become known as the polikarpov design bureau. production models included i-5, i-15, i-15bis, i-153, i-16, r-5, and r-zet aircraft. polikarpov also built airco dh.9a (which later became polikarpov r-1/polikarpov r-2) and airco dh.4 during the 1920s and 1930s.