Alekseyev I - 212 The Alekseyev I - 212 was a twin - engine d , jet fighter designed in the USSR in 1947 by Experimental Design Bureau 21 ( OKB ) . It was a two - seat variant of the I - 21 ( " Istrebitel " - Fighter ) that had been designed in response to a requirement for a very long - range fighter issued by the Soviet Air Forces in 1946 . Intended as an escort fighter , it was also designed for use as a night fighter and reconnaissance aircraft . Sources are contradictory about the construction of a prototype , but it is known that the aircraft never flew . Development . After working as Lavochkin ' s right - hand man during World War II , Semyon Alekseyev was appointed as Chief Designer of OKB - 21 at Gor ' kiy in 1946 . The Council of the People ' s Commissars directed Alekseyev , among others , to develop jet fighters using more powerful engines than the captured German examples and their Soviet - built copies . The OKB was tasked to design a single - seat jet fighter that could meet the very demanding specification of a maximum speed of and a range of with drop tanks . The OKB responded with the I - 21 , which was planned to be built in several variants . Development of the I - 212 , one such variant , began in 1947 . It was a twin - engined , all - metal , two - seat jet fighter . The round , streamlined fuselage was optimized to reduce drag and house the considerable amount of equipment and fuel required by the Air Force . It had mid - mounted straight laminar flow wings and the engine nacelles were mounted in the middle of the wing , with the spars continued by banjo rings around the engines . The cruciform tail unit was swept at 45° . To save weight , the main load - bearing structures of the airframe were constructed from V - 95 aluminum alloy and high - strength steel . " Elektron " magnesium alloy was used for many components and castings . The aircraft used a tricycle undercarriage with the main wheels retracting into the fuselage . Hydraulically actuated air brakes were fitted either side of the rear fuselage . The pilot and gunner / radio operator sat in tandem , back to back in a single pressurized cockpit . They were protected by armor plates to their front and rear , as well as by a bulletproof windscreen . Each man had an ejection seat . The aircraft was intended to use Klimov VK - 1 engines , a derivative of the Rolls - Royce Nene , but the Klimov engine was still under development , so Nenes were substituted instead . The aircraft carried a Toryii - 1 radar for use by the gunner / radio operator . The information on the design ' s armament is contradictory . British aviation historian Bill Gunston says that the forward - facing armament consisted of a Nudelman - Suranov NS - 37 autocannon and two Nudelman - Suranov NS - 23 autocannons . The radio operator controlled a tail barbette with two Berezin B - 20 autocannon . The aircraft carried 75 rounds for the NS - 37 and 200 rounds apiece for the NS - 23s . Russian aviation historian Yefim Gordon argues that the aircraft ' s standard armament consisted of four NS - 23 guns in the nose and two B - 20s in the barbette ; each gun having 150 rounds apiece . Alternatively , one NS - 37 and two NS - 23 guns could be fitted , with two more NS - 23 in the tail . He gives the ammunition load for this configuration as 40 rounds for the 37 mm gun and 150 each for the 23 mm guns . Gordon also mentions that each wing carried one hardpoint that could carry a drop tank with of fuel or a single bomb . Gordon and Gunston also differ on the fate of the aircraft . Gunston says that a prototype began taxiing tests on 30 June 1948 , but makes no mention that it flew at any time . Gordon , however , claims that no prototype was built . A training version designated UTI - 212 was planned if the aircraft had gone into production . He also mentions an I - 217 project in two versions with forward - swept and sweptback wings . Neither author gives a good explanation as to why the aircraft never flew .