Shpitalny Sh - 37 The Shpitalny Sh - 37 ( ) was the first indigenous Soviet aircraft cannon , designed by Boris Shpitalniy at OKB - 15 . The gun saw limited production and was installed in few aircraft before being replaced by the competing Nudelman - Suranov NS - 37 designed at OKB - 16 . It was installed on a military - trial basis on two short series of aircraft . Installed through the engined block of the Yak - 7 - 37 it was known as MPSh - 37 , where " MP " stands for " motornaya pushka " . As installed in the underwing gun pod s of the Il - 2 it was known as ShFK - 37 ( ) . History . In 1940 , after the Red Army accepted for service the 61 - K 37 mm anti - aircraft gun , the VVS leadership decided to equip some fighters and a part of the upcoming production series of the Ilyushin Il - 2 ground attack aircraft with a 37 mm autocannon capable of firing the same shell . Shpitalniy designed a gun that was gas operated and magazine fed , which however used a less powerful cartridge than the 61 - K gun . By early 1941 , a prototype Sh - 37 was flight tested on a LaGG - 3 fighter . As installed in the LaGG - 3 , the gun together with its magazine weighed 208 . 4 kg . In this test it achieved a rate of fire of 184 rounds per minute . At the end of June 1941 , it was decided that within 45 days 40 more Sh - 37 were to be produced for military trials . These were manufactured as planned by factory 74 . In 1942 , the same factory produced a further 196 Sh - 37 guns . The first LaGG - 3 aircraft equipped with the Sh - 37 gun were delivered to the 42nd IAP in the beginning of 1942 . In August 1942 , a small series of 22 Yak - 7 - 37 , equipped with the same gun , passed military trials with the same 42nd IAP , led by Boris Shinkarenko . The Sh - 37 was powerful enough to down an enemy fighter with a single hit . Its shell could punch a hole with an area of over . The MPSh - 37 was supplied with 20 rounds of ammunition in this aircraft . The Yak - 7 - 37 was additionally armed with two UBS 12 . 7 mm machine guns , with 450 rounds total ammunition . The weight of fire of the Yak - 7 - 37 was 4 . 15 kg / s ( 9 . 15 lb / s ) . The length of the Sh - 37 gun necessitated moving the cockpit some 40 cm rearwards , and the weight of the Yak - 7 - 37 increased by some 200 kg compared to its proximate predecessor , the Yak - 7B . By mid - 1941 an Il - 2 exemplar was experimentally fitted with a pair of Sh - 37 cannons in underwing pods . By September 15 , this aircraft had passed ground and air firing test at the factory , and was presented for state trials , which were conducted between September 23 and October 12 , 1941 . Each Sh - 37 gun on this Il - 2 was provisioned with 40 rounds of ammunition . The large ammunition magazine did not fit in the wings and was housed in a rather bulky fairing . As fitted to the wing of the Il - 2 , the weight of the Sh - 37 with the assembly and magazine was 302 . 5 kg . The rate of fire measured in this latter installation was 169 rpm ; muzzle velocity was 894 m / s . The underwing position of the gun nacelles in the Il - 2 had the unpleasant effect that when the guns were fired in a dive , their recoil caused the aircraft to pitch down even further , thus reducing salvo accuracy . The flight characteristics of the Il - 2 armed with the Sh - 37 guns were substantially worse than for the regular versions fitted with 20 or 23 mm guns . It was slower and more difficult to handle . Its top airspeed was only at sea level and at . Its rate of climb also deteriorated and the length of its take - off run had increased . Nevertheless , between December 1942 and January 1943 , a limited production run of nine Il - 2s armed with Sh - 37 guns was delivered to the 688th Attack Air Regiment ( ShAP ) of the 228th Attack Air Division ( 16th Air Army ) for military trials . These aircraft took part in the combat around Stalingrad that winter . The Sh - 37 gun proved somewhat effective against the German tanks of the day . It could pierce the armor of light tanks without problem and at favorable angles it was effective against German medium tanks as well . However , effective use of the gun required a high degree of skill from the pilots . Besides the diving issue , poor firing synchronization between the guns ( as installed in these aircraft ) caused them to also veer laterally off - course when the Sh - 37 guns were fired . Consequently , bursts of only two or three rounds were practical . To compound the problems , the Sh - 37 guns were also rather unreliable , with frequent jamming occurring . Even though the Sh - 37s were installed in pairs , this actually decreased the overall reliability of the aircraft as a weapon system , because the jamming of a single gun meant that the Il - 2 could not fire safely any longer , due to the strong , asymmetric recoil from a single gun having a very strong destabilizing effect on the aircraft . After these experiences , the Il - 2 with Sh - 37 guns was not ordered in mass production .