In parallel with the I-26 (or Ya-26), the Yakovlev design bureau developed a two-seat version under the designation Yakovlev Ya-27. One pre-production I-26 was completed to this configuration. It was intended to serve not only as a dual-control fighter trainer, but also as a liaison and unit support aircraft. Compared with the I-26, the Ya-27 was simplified and of reduced weight, the tandem cockpits being enclosed by an extended glazed canopy. The resulting Yak-7 aircraft entered production in May 1941 and was soon found to have better flying qualities than those displayed by series Yak-1s. This performance, combined with the urgent need for more fighters, led to production of a single-seat version of which the first was flown in June 1941; in the following month the fighter was officially designated Yak-7A and the two-seater Yak-7V. By the end of 1941 a new single-seater, the Yak-7B, had replaced the Yak-7A . Total delivery of all versions of the Yak-7 was 6,399 aircraft, production terminating in early 1943; of this number, some 1,500 were Yakovlev Yak-7Vs.