Polikarpov I - 5 The Polikarpov I - 5 was a single - seat biplane which became the primary Soviet fighter between its introduction in 1931 through 1936 , after which it became the standard advanced trainer . Following Operation Barbarossa , which destroyed much of the Soviet Air Forces ( VVS ) , surviving I - 5s were equipped with four machine guns and bomb racks and pressed into service as light ground - attack aircraft and night bombers in 1941 . They were retired in early 1942 as Soviet aircraft production began to recover and modern ground - attack aircraft like the Ilyushin Il - 2 became available . Development . The 1928 Five - Year Plan ordered the Tupolev design bureau to develop a mixed - construction ( metal and wood / fabric ) biplane fighter powered by a Bristol Jupiter VII engine with the first prototype completed by 1 September 1929 . The new fighter was designated I - 5 ( " Istrebitel " — Fighter ) , but had the internal Tupolev designation of ANT - 12 . Concurrently , Nikolai Nikolaevich Polikarpov ' s group was tasked with creating a wood - construction aircraft designated as the Polikarpov I - 6 to the same specification . The I - 5 design , begun by Pavel Sukhoi , under the supervision of Andrei Tupolev , lagged because the Tupolev bureau was preoccupied with large bombers . As the result the I - 5 and I - 6 projects were unified in 1929 under Polikarpov ' s leadership , although neither project met its specified completion date . Nikolai Polikarpov was arrested by the OGPU in September 1929 for the crime of industrial sabotage for these failures and sentenced to death , although this was commuted to ten years imprisonment in a labor camp . In December 1929 the OGPU gathered a number of aircraft engineers together at Butyrka prison , including Polikarpov , and formed the Internal Prison Design Bureau ( " Konstruktorskoye Byuro Vnutrenniya Tyurma " — KB VT ) under the leadership of Dmitry Pavlovich Grigorovich . The KB VT was transferred to quarters on the grounds of Factory ( " Zavod " ) Nr . 30 in Moscow - Khodinka in early 1930 . Shortly afterwards Polkarpov replaced Grigorovich as the head designer when his concept for the I - 5 was approved by the OGPU . The full - scale mock - up was approved on 28 March 1930 and the first prototype , designated VT - 11 ( " Vnutrenniya Tyurma " — Internal Prison ) , was completed a month later . It made its first flight on 30 April 1930 and was fitted with an imported supercharged Jupiter VII . It was painted in silver with a red cheat line ; a red " VT " was superimposed on the red star on the rudder . The second prototype , known as the VT - 12 , had a Jupiter VI engine , and took to the air on 22 May , bearing the name " Klim Voroshilov . " The two prototypes also differed in minor details regarding the shape of the tail and the construction of the landing gear . All this meant a slight difference in weight and performance between the two prototypes was present , with the second being slightly heavier and faster , while the first had a slight range advantage and a higher service ceiling . The third prototype , designated as the VT - 13 and inscribed with " A Gift for the XVIth Congress of the Party " , was powered by a Soviet - built M - 15 engine with a NACA cowling , but this proved to be unreliable and was not put into production . The second prototype passed its State acceptance trials on 13 August 1931 and was ordered into production a month later on 13 September . One problem noted during the trials was a tendency to make an uncontrolled 180° turn when landing in light winds . Shortening the landing gear by and moving them cured the problem . The engineer who suggest the change was awarded the Order of the Red Star for his ingenuity . Ten pre - production aircraft had already been ordered and they were assembled between August and October . They all had imported engines fitted , but trialled various small improvements for the production aircraft that included cooling vents for the crankcase , introduction of a pitot tube and static vent in the starboard upper wing , a faired headrest for the pilot , and a metal propeller whose pitch could be adjusted on the ground . Design . The I - 5 was a single - seat biplane with staggered wings in a sesquiplane configuration with fixed landing gear and a tailskid . The aircraft was of mixed construction , with the fuselage being made of a framework of welded steel tubes covered by a fabric skin over the rear fuselage , with the front fuselage section being covered by detachable duralumin panels as far back as the rear of the cockpit . There were also detachable panels allowing easy access to the tailskid shock absorber . The fabric skin was laced for tightness and the seams were covered with calico . A fireproof bulkhead separated the fuel tank from the engine and a fire extinguisher was fitted with outlets to the fuel pump , inlet pipe and carburetor . The conventional landing gear was connected by a one - piece axle and some aircraft were fitted with teardrop - shaped spats covering the wheels . Initially the tailskid was fixed , but later aircraft had smaller skids that moved in concert with the rudder . Rubber rings were used as shock absorbers on the landing gear . The wings were built with two spars . The upper wing was made in three parts , with the middle section being of duralumin and the outer ones being made of wood . The wooden lower wings were built in single sections , using a Göttingen - 436 profile . The duralumin N - type struts that separated the wings , and attached the upper wing to the fuselage , had a teardrop profile and were reinforced with steel bracing wires . Laced lacquered fabric covered the empennage and wings , except for the roots of the lower wings which were covered in plywood and the leading edges of the wings were skinned in duralumin for the first . Ailerons were fitted only to the upper wing . All movable control surfaces and the tail section were built with doped fabric over metal framing . Bracing wires above and below the tail were fitted on the prototypes , but production aircraft replaced the lower wires with a strut on each side . The horizontal tail was offset to port to compensate for the engine ' s torque , but it could be adjusted on the ground . Some early production aircraft had imported Bristol Jupiter VI engines with a metal cowling , but the bulk of the production aircraft used the M - 22 license - built copy , both of , with a Townend ring . Early aircraft usually had a fixed - pitch wooden propeller with a diameter of , but these were replaced by a duralumin propeller without a spinner that could have its pitch adjusted on the ground . Two synchronized PV - 1 machine gun s were fitted in the fuselage with 600 rounds apiece with an OP - 1 telescopic sight . It was hoped to fit another pair , but the extra weight adversely affected the aircraft ' s performance during tests . Two small Der - 5 underwing bomb racks were fitted that could carry one bomb apiece . Beam - type bomb racks were evaluated on the I - 5 that could carry a pair of bombs , but these had such adverse effects on its performance that they were rejected for service use . One of the tests with these racks had the aircraft diving down upon the target ; the first example of dive bombing in the Soviet Union . The I - 5 was also used to evaluate the accuracy of the RS - 82 rocket , although they are not known to have been used by the aircraft in service . I - 5s called up during the emergency in 1941 were converted for use as fighter - bomber s by adding two more machine guns , and some aircraft were fitted with the heavy bombs that had been rejected earlier . The ground - attack version is sometimes referred to as the I - 5LSh . Test pilot Mark Gallai described the flying qualities of the I - 5 thus : " After flying it I was convinced that the I - 5 is quite a handful , a capricious aircraft . However , if you are careful with the controls and do not offend the machine with rough actions , it will not depart controlled flight . " Operational history . 54 I - 5s were delivered to the VVS by 1 October 1931 , and 66 by the end of the year . These were all aircraft from Zavod Nr . 1 at Khodinka , but Zavod Nr . 21 in Gorkii began deliveries the following year . It delivered ten in 1932 , 321 in 1933 and 330 in 1934 . Zavod Nr . 1 delivered 76 in 1932 before beginning production of the Heinkel HD 37 as the I - 7 . The I - 5 was first delivered to units in the Leningrad , Ukraine and Transbaikal Military District s and comprised 20 % of the VVS ' s fighter force by the end of 1932 . During 1933 deliveries began to units in the Far Eastern , Belorussian and Moscow Military District s and they comprised 40 % of the fighter strength by the end of the year . By the end of 1934 most of the Polikarpov I - 3 s and Tupolev I - 4 s had been replaced and deliveries had begun to Naval Aviation . The I - 5 began to be replaced by the Polikarpov I - 15 in 1936 , and was completely phased out from front - line use by the end of 1937 , but continued to be employed as an advanced trainer . Following the German Invasion of the Soviet Union in June 1941 , the heavy losses of front - line aircraft endured by the VVS together with the disruption of aircraft production resulted in I - 5s being removed from training units and returned to combat service as ground - attack aircraft or night bombers until early 1942 . Some I - 5s were used by the 605th and 606th Fighter Regiments ( " Istrebitel ' nyye Aviatsionyye Polki " ( IAP ) ) during the defence of Moscow as night bombers until re - equipping in February 1942 . The 2nd Ground Attack Regiment ( " Shturmovoy Aviatsionyye Polki " ( ShAP ) ) was raised in September 1941 in the Crimea from reservists and the Kachin Flying School . By 10 October thirty - two I - 5s were on hand , although attrition had reduced them to sixteen serviceable . They were down to a total of a dozen aircraft by 18 October . They served until 1 February 1942 when the regiment was withdrawn for conversion to Ilyushin Il - 2 s and redesignated as the 766th ShAP . The 11th ShAP was raised by the Air Force of the Black Sea Fleet on 22 September 1941 . On 18 October it mustered eighteen serviceable and fifteen unserviceable I - 5s , although this was reduced to eleven serviceable and eight unserviceable aircraft by 7 November . It kept the I - 5s in service until 1 February 1942 when the regiment was reorganized . Variants . The I - 5 was involved in tests of the Zveno project where a Tupolev TB - 3 heavy bomber carried three I - 5s as parasite fighter s . One I - 5 was carried was on each wing and a third over the fuselage . Ramps were used to get the wing - mounted aircraft to their places , but the fuselage - mounted aircraft had to be lifted by hand . This was so cumbersome that they were generally used solely as an extra powerplant for the TB - 3 later in the program . The aircraft used in these trials used the longer landing gear with smaller tires originally used in the prototypes . A two - seat conversion trainer , designated the I - 5UTI ( " Uchebno - Trenirovochnyy Istrebitel " — Fighter Trainer ) , was built by one of the factories . Only about twenty are believed to have been built . The cockpit was moved back and a second one inserted in front of it .