Yakovlev Yak - 7 The Soviet Yakovlev Yak - 7 was developed from the earlier Yak - 1 fighter , initially as a trainer but converted into a " heavy " fighter . As both a fighter and later reverting to its original training role , the Yak - 7 proved to be a capable aircraft and was well liked by air crews . The Yak - 7 was simpler , tougher and generally better than the Yak - 1 . Design and development . In 1939 , Alexander Yakovlev designed a tandem - seat advanced trainer , originally designated " I - 27 " and then " UTI - 26 " , offered along with the original I - 26 proposal that became the Yak - 1 . The " UTI " ( " Uchebno Trenirovochnyi Istrebitel " , translated as : Training Fighter ) was intended to give pilots - in - training experience on a high - performance aircraft before transitioning to a fighter . With development work stated in 1940 , the UTI - 26 differed from its predecessor in its larger span wing being placed farther back for balance as well as having two cockpits with dual controls and a rudimentary communication system . It was armed with a single ShKAS machine gun in the cowling , mainly for use in training , but Yakovlev envisioned a multi - purpose aircraft that could also undertake courier and light transport duties at the front . The first production aircraft known as Yak - 7UTIs retained a retractable main landing gear , but beginning in the summer of 1941 , a fixed landing gear variant , the Yak - 7V ( Vyvozoni for Familiarization ) was substituted . The factory reasoned that production would be simplified and that reduced performance would not be detrimental for a trainer . Yak - 7UTIs and Yak - 7Vs were also equipped with skis for winter operations . A factory team from N° 301 , headed by K . A . Sinelshchikov , was detached from the Yakovlev OKB to supervise production of Yak - 7UTI . One of these aircraft ( serial number 04 - 11 ) was fitted with an armored backrest plate over the rear position , self - sealing fuel tank s which filled with inert gas as they emptied , three " RO " rocket launchers under each wing for as many RS - 82 rockets , an axial ShVAK cannon firing through the propeller spinner , with 120 rounds , and two 7 . 62 mm ShKAS machine guns under the cowling , each with 750 rounds . The rear cockpit position was retained , allowing it to accommodate a second seat ( without controls ) for fast courier and transport duties or a fuel tank for extended range . The additional space could also house bombs or other gear . The engine was an M - 105P and the model was designated Yak - 7 / M - 105P . Sinelshchikov did not inform Yakovlev about the conversion and when he learned about it , Yakovlev remained sceptical of the need for the changes . After brief factory trials , the aircraft turned out to be better than the single - seat Yak - 1 , thanks to the modifications already applied to the UTI as well as revised undercarriage with bigger tires and wheels , more efficient brakes and revised elevators , among other changes . Yakovlev submitted the Yak - 7 to the authorities who approved it immediately . The firing tests at the scientific trials Polygon for aircraft armament ( NIPAV ) were a success and the armament was found to have no effect on the flight characteristics or the general performances of the new fighter . The aircraft ' s stability as a firing platform was judged far better than that of the Yak - 1 , the Lavochkin - Gorbunov - Gudkov LaGG - 3 and Mikoyan - Gurevich MiG - 3 . The GKO and the NKAP issued decrees in August 1941 for the Yak - 7 to be produced by Factories N°301 and N°153 , but the Factory 301 had to be evacuated to Novosibirsk where it merged with N° 153 . So , just 62 aircraft were produced in 1941 : 51 in September – October by Factory N° 301 and 11 by N°153 in December . Test pilot A . N . Lazarev noted the good flight characteristics , how easy it was to get out of a spin , how well it behaved when diving , characteristics that he considered safer than those of the Yak - 1 . But the Yak - 7 showed some defects : the M - 105P engine piping , the landing gear locking system , the tires and the tail wheel were identified . The Yak - 7 was introduced into the production line and the first batch of 60 reached operational squadrons by the end of 1941 . Another important variant was the Yak - 7 / M - 105PA . On this model , the two ShKAS on the cowling had been replaced by two UBS machine guns with 400 rounds ( 260 for the left and 160 for the right ) . It was powered by an M - 105PA engine with an axial ShVAK cannon with 120 rounds . Oil and glycol radiators had been widened and refined and slightly tilted downward . The insulation of the airframe was improved , tail wheel was totally retractable ; joints and skin were more carefully made ; panels on engine cowling fitted better ; the propeller reduction gear worked better ; an electro - pneumatic reloading system was installed ; canopy frame was reinforced . The Yak - B made 27 tests flights in January and February 1942 . The reports noted that while the aircraft " was not inferior to the LaGG - 3 and MiG - 3 and to foreign fighters in service in the USSR " , it was more stable and had better flight characteristics . Subsequently , the GKO authorised production at Factory N°153 in place of the Yak - 7A , from April 1942 and 261 machines were built until July . After 20 May , the aircraft were equipped with a tank behind the pilot ’ s seat , but the pilots that used the Yak - 7 on Stalingrad and on the Kuban removed it as it was not protected and affected the flight characteristics . Generally , the Yak - 7B pleased its pilots . They reported that it was easy to fly at all altitudes , stable and easy to maintain and although it did not climb as quickly as a Messerschmitt Bf 109 , it was as manoeuvrable and fast , except in the vertical plane . But defects were also noted : there was too much drag from the radiators , the canopy glass was of bad quality ; the pilot was not protected enough , taking - off and landing distances were too long and , above all , it was underpowered . Yakovlev suggested Klimov , the engine builder , some modifications that resulted in the M - 105PF which was more powerful . With this modified engine , the Yak - 7B top speed was of , it climbed much faster up to and it was more manoeuvrable both in the horizontal and the vertical planes . But because the rear tank was removed , its range was reduced and the CG was moved too forward , while M - 105 defects ( glycol and oil overheating , oil leaks etc . ) persisted . Among the engine and armament options was the Yak - 7 - 37 fitted with a MPSh - 37 cannon , ( MPSh - " motornaya pushka Shpital ' novo " - engine mounted Shpital ' nyy cannon ) , mounted between the engine cylinder blocks , firing through the propeller spinner . Operational history . The Yak - 7 proved to be an effective close support fighter although the first two - seaters were considered nose - heavy , consequently , the factory introduced a rear cockpit fuel tank . Pilots complained about the fuel tank ' s vulnerability since it was unarmored , and it was usually removed in the field . There were constant changes to the design based on combat observations including a definitive single - seat variant , the Yak - 7B , which was produced in large numbers . After the war , some Yak - 7V trainers were provided to the Poles and a single Yak - 7V was delivered to the Hungarians for familiarization with the Yak - 9 fighter . After trials in April – May 1942 , a small batch of 22 Yak - 7 - 37s was authorised , all of which were issued to the 42nd IAP at the North - Western front , where they proved highly successful both in air to air combat and ground attack .