ISBN: | 978-5-5106-5326-7 |
High Quality Content by WIKIPEDIA articles! Polikarpov DI-1 (also known as 2I-N1, Russian: Поликарпов ДИ-1 (2И-Н1)) was a prototype Soviet two-seat fighter designed during the 1920s. The sole prototype built crashed on its ninth flight, due to manufacturing defects, and the program was cancelled.