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The Nudelman-Suranov NS-45 was an enlarged version of the
Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
Nudelman-Suranov NS-37 The Nudelman-Suranov NS-37 (russian: Нудельман - Суранов НС-37) was a aircraft cannon, which replaced the unreliable Shpitalny Sh-37 gun. Large caliber was planned to allow destruction of both ground targets (including armoured ...
aircraft
autocannon An autocannon, automatic cannon or machine cannon is a fully automatic gun that is capable of rapid-firing large-caliber ( or more) armour-piercing, explosive or incendiary shells, as opposed to the smaller-caliber kinetic projectiles (bull ...
. It was evaluated for service on 44
Yakovlev Yak-9 The Yakovlev Yak-9 (russian: Яковлев Як-9) is a single-engine, single-seat multipurpose fighter aircraft used by the Soviet Union and its allies during World War II and the early Cold War. It was a development of the robust and successf ...
K aircraft during
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, but proved to stress the airframes too much. The NS-45 was also mounted on the prototype
Tupolev Tu-1 The Tupolev Tu-1 was a prototype Soviet night fighter variant of the Tupolev Tu-2 medium bomber that first flew after the end of World War II. It was cancelled when its experimental Mikulin AM-43V engines reached the end of their service life. De ...
night fighter A night fighter (also known as all-weather fighter or all-weather interceptor for a period of time after the Second World War) is a fighter aircraft adapted for use at night or in other times of bad visibility. Night fighters began to be used i ...
after the end of World War II.


Design and development

The NS-45 was created as a result of a July 1943 decision of the
State Defense Committee The State Defense Committee (russian: Государственный комитет обороны - ГКО, translit=Gosudarstvennyĭ komitet oborony - GKO) was an extraordinary organ of state power in the USSR during the German-Soviet War (Grea ...
to arm Soviet fighters with 45 mm autocannons. As with the 37 mm autocannons already installed in some Soviet and lend-lease single-engine fighters, the intended method of installation of the 45 mm gun was to have its barrel pass through the engine block and the empty propeller shaft, in this case that of the
Yak-9 The Yakovlev Yak-9 (russian: Яковлев Як-9) is a single-engine, single-seat multipurpose fighter aircraft used by the Soviet Union and its allies during World War II and the early Cold War. It was a development of the robust and successf ...
. Consequently, the main difficulty in designing the 45 mm autocannon was the limitation imposed by the engine blocks available for this aircraft. Accounting for the diameter of the 45 mm shell, the Yak-9 engine blocks only allowed a wall thickness of 4 mm for the new gun's barrel, which was almost half the thickness of the barrel wall of the NS-37. (Another source gives 55 mm as the diameter of opening in the engine reducer shaft, resulting in a wall thickness of 3.75 mm for the NS-45 barrel relative to 7.1 mm for the NS-37 barrel, both measured at this spot which was approximately 61 cm away from the muzzle.) The decision of the Defense Committee was followed by a short design competition between Soviet designs bureaus
OKB OKB is a transliteration of the Russian initials of "" – , meaning 'experiment and design bureau'. During the Soviet era, OKBs were closed institutions working on design and prototyping of advanced technology, usually for military applications. ...
-15 and OKB-16. The former proposed an enlarged version of their unreliable
Shpitalny Sh-37 The Shpitalny Sh-37 (russian: Шпитальный - Ш-37) was the first indigenous Soviet aircraft cannon, designed by Boris Shpitalniy at OKB-15.Широкорад А.Б. (2001) ''История авиационного вооружения'' ...
; although they made a prototype that passed factory tests in a
LaGG-3 The Lavochkin-Gorbunov-Gudkov LaGG-3 (Лавочкин-Горбунов-Гудков ЛаГГ-3) was a Soviet fighter aircraft of World War II. It was a refinement of the earlier LaGG-1 and was one of the most modern aircraft available to the Sov ...
, their 45 mm gun was not accepted for state trials because of the known issues with the Sh-37 design. OKB-16 presented an enlarged version of their successful NS-37. The recoil force of the NS-45 peaked at seven tons, a force roughly 40% greater than that experienced with the NS-37 (about 5.5 tons). Consequently, the NS-45 was fitted with a
muzzle brake A muzzle brake or recoil compensator is a device connected to, or a feature integral to the construction of, the muzzle or barrel of a firearm or cannon that is intended to redirect a portion of propellant gases to counter recoil and unwanted ...
—a first in Soviet aircraft-gun design.Широкорад А.Б. (2001) ''История авиационного вооружения'' Харвест (Shirokorad A.B. (2001) ''Istorya aviatsionnogo vooruzhenia'' Harvest. ) (''History of aircraft armament''), pages 130–132 Concomitantly with the gun design, a new cartridge was developed using the standard 45 mm fragmentation shell of the 21-K anti-aircraft gun. (This projectile had a tracer that burned for eleven seconds and was fitted with the MG-8 contact fuse.) The total length of the new cartridge was limited to the same value as for the NS-37 ammunition—328mm. In order to accommodate the larger shell, the case body (brass) was necked up and also slightly reduced in length from 195 mm of the NS-37 ammunition to 185 mm. The resulting 45 mm cartridge weighted 1.93 kg, of which 1.065 kg was the weight of its shell. The muzzle velocity of the NS-45 was 780 m/s and its rate of fire was around 260–280 rounds per minute.


Production and service

The NS-45 was built in small numbers at Factory Number 74 in the last two years of the war; 75 exemplars were made in 1944 and 120 were made in 1945.


Yak-9K

In fighters, the NS-45 gun was first installed on a modified Yak-9T, which was normally armed with a NS-37 gun. This aircraft, with constructor number 0121, effectively became the first Yak-9K prototype. The "K" suffix stood for "Krupnokalibernyi", meaning large caliber. The protruding barrel and muzzle brake of the NS-45 made the Yak-9K some 20 cm longer than the Yak-9T. The NS-45 was supplied with 29 rounds of ammunition in the Yak-9K, which were fed using a belt. The only other armament installed on the Yak-9K was a
UBS UBS Group AG is a multinational Investment banking, investment bank and financial services company founded and based in Switzerland. Co-headquartered in the cities of Zürich and Basel, it maintains a presence in all major financial centres ...
(a propeller-synchronized 12.7 mm machine gun) supplied with 200 rounds of ammunition. The theoretical weight of fire of the Yak-9K was 5.53 kg/s (12.2 lb/s), which gave it a considerable advantage in this department relative to most single-engine German aircraft of the time except the "flying gun-batteries" such as the
Fw 190 The Focke-Wulf Fw 190, nicknamed ''Würger'' (" Shrike") is a German single-seat, single-engine fighter aircraft designed by Kurt Tank at Focke-Wulf in the late 1930s and widely used during World War II. Along with its well-known counterpart, ...
A-6/R1 or the
Bf 109 The Messerschmitt Bf 109 is a German World War II fighter aircraft that was, along with the Focke-Wulf Fw 190, the backbone of the Luftwaffe's fighter force. The Bf 109 first saw operational service in 1937 during the Spanish Civil War an ...
G-6/R6. Compared to these, the Yak-9K maintained however good horizontal maneuverability because its wings were not loaded with armament. Developed in late 1943, the Yak-9K
prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...
was tested at the Central Research Institute of the Soviet Air Force (VVS NII) between January 12 and April 8, 1944. Between April and June 1944 a limited production run of the aircraft, with the cockpit pushed further to the back to improve the center of gravity, was manufactured at a plant in
Novosibirsk Novosibirsk (, also ; rus, Новосиби́рск, p=nəvəsʲɪˈbʲirsk, a=ru-Новосибирск.ogg) is the largest city and administrative centre of Novosibirsk Oblast and Siberian Federal District in Russia. As of the Russian Census ...
and delivered for military trials to the 3rd Fighter Air Corps.Yefim Gordon and Dmitri Khazanov. ''Soviet Combat Aircraft of the Second World War, Volume One: Single-Engined Fighters''. Earl Shilton, Leicester, UK: Midland Publishing Ltd., 1998. , pp. 146–147 For military (combat) trials 44 Yak-9Ks of this limited production run were used. These trials took place between 13 August and 18 September 1944 at the
3rd Belorussian Front The 3rd Belorussian Front () was a Front of the Red Army during the Second World War. The 3rd Belorussian Front was created on 24 April 1944 from forces previously assigned to the Western Front. Over 381 days in combat, the 3rd Belorussian Fron ...
, and from 15 January 1945 to 15 February 1945 at the
2nd Belorussian Front The 2nd Belorussian Front (Russian: Второй Белорусский фронт, alternative spellings are 2nd Byelorussian Front) was a military formation, of Army group size, of the Soviet Army during the Second World War. Soviet army g ...
. The
Soviet Air Forces The Soviet Air Forces ( rus, Военно-воздушные силы, r=Voyenno-vozdushnyye sily, VVS; literally "Military Air Forces") were one of the air forces of the Soviet Union. The other was the Soviet Air Defence Forces. The Air Forces ...
units involved were the 274th Fighter Aviation Regiment (IAP) of the 278th Fighter Aviation Division (IAD) and the 812nd IAP of the 65th IAD. Twelve German aircraft were claimed by Yak-9K fighters, with an average expenditure of ten rounds per target. Of these twelve German aircraft claimed by Yak-9K pilots, eight were Fw 190 and four were Bf 109G. Combat experience with the Yak-9K showed that although the NS-45 cannon proved deadly to enemy aircraft, realistically only its first shot could be aimed. A three-round burst, even when fired near the maximum airspeed of the Yak-9K, resulted in a noticeable loss of both airspeed and stability of the aircraft. Sometimes oil and water lines sprung leaks after the gun was fired. Firing the NS-45 at airspeeds below 350 km/h even shook the pilot back and forth as if in an automobile suddenly decelerating and accelerating. Another issue affecting the effectiveness of the Yak-9K was that it had a poorer power to weight ratio compared to its proximate predecessor, although this was mostly due to its larger fuel tanks rather than the weight of the armament; its fuel tanks had been enlarged from the 440-liter tanks of Yak-9T to 650-liter tanks, allowing it to carry an additional 153 kg of gasoline. The loss of airspeed relative to the Yak-9K was about 40 km/h at 5,000 m, and climbing to this altitude took about a minute longer with the Yak-9K. In an attempt to address this problem, some of the Yak-9K already in service were retrofitted with smaller 480-liter tanks. To compensate for the Yak-9K's poor maneuverability in the vertical plane, pilots of the 812th IAP developed tactics that essentially employed the aircraft as a
heavy fighter A heavy fighter is a historic category of fighter aircraft produced in the 1930s and 1940s, designed to carry heavier weapons, and/or operate at longer ranges than light fighter aircraft. To achieve performance, most heavy fighters were twin-eng ...
, using it for surprise attacks on bombers, and providing it with an escort by nimbler
Yak-3 The Yakovlev Yak-3 (Russian: Яковлев Як-3) was a single-engine, single-seat World War II Soviet fighter. Robust and easy to maintain, it was much liked by both pilots and ground crew.Glancey 2006, p. 180. One of the smallest and lighte ...
s flying top cover. Ultimately, it was decided that the Yak-9K would not go into mass production. Besides the reliability and airframe performance issues, another contributory reason was that the German bombers still active on the Eastern front at this point in the war were mainly Fw 190 '' Jabo'', and the 45 mm shell was overkill for these. A total of 53 Yak-9Ks had been built by then.


Other aircraft

The NS-45 was also tried on an
Ilyushin Il-2 The Ilyushin Il-2 (Russian: Илью́шин Ил-2) is a ground-attack plane that was produced by the Soviet Union in large numbers during the Second World War. The word ''shturmovík'' (Cyrillic: штурмовик), the generic Russian term ...
, with one gun mounted in each wing, but the design was not put into series production. On August 20, 1943, the People's Commissariat of Aviation Industry of the USSR ordered that an Il-2 be tested with the new 45 mm aircraft guns. An Il-2 exemplar fitted with the new guns had been manufactured by September 10, 1943, when it was sent to the VVS NII for trials. Due to various issues which arose integrating the NS-45 gun with this aircraft, testing was delayed until February 8, 1944. The results were disappointing; the Il-2-mounted NS-45s exhibited poor accuracy hitting tank-size targets and their recoil was almost twice what the Il-2's wings could safely handle (about 4000 tons-force).В. Перов, О. Растренин, "Ил-2 против танков", ''Техника и вооружение. Вчера, сегодня, завтра'' 2001/7, pp. 1–10 (info from page 10); the same text/information appears on pp. 86–87 in the larger monograph (100 pp.) by the same authors published in issue 2001/5-6 of ''Авиация и Космонавтика'' One of the three versions of the prototype ground attack (shturmovik) Tu-2Sh was equipped with two NS-37s and two NS-45s as frontal armament. This variant was tested sometime in 1946. A more substantial test program took place between 30 December 1946 and 3 October 1947 with the
Tupolev Tu-1 The Tupolev Tu-1 was a prototype Soviet night fighter variant of the Tupolev Tu-2 medium bomber that first flew after the end of World War II. It was cancelled when its experimental Mikulin AM-43V engines reached the end of their service life. De ...
night fighter A night fighter (also known as all-weather fighter or all-weather interceptor for a period of time after the Second World War) is a fighter aircraft adapted for use at night or in other times of bad visibility. Night fighters began to be used i ...
prototype, which was fitted with two NS-45s in the nose—each one supplied with 50 rounds—and with two NS-23s in the wing roots. The Tu-1 was abandoned because of its unreliable engines.


See also

*
BK 5 cannon The Rheinmetall ''Bordkanone'' 5, or BK-5, was a WWII-era German 50 mm autocannon primarily intended for use against Allied heavy bombers, such as the United States Army Air Forces's (USAAF) Boeing B-17 Flying Fortress. The shells had a hi ...
*
Ho-401 cannon Ho-401 was a Japanese aircraft autocannon that saw limited, if any, use during World War II. It was a large-caliber version of the 37 mm Ho-203 cannon Ho-203 was a Japanese autocannon that saw considerable use during World War II. It was ...
* N-57/OKB-16-57


References


Further reading

*


External links


NS-45 on RAM

Ammo comparison: ShKAS 7.62, UB 12.7, ShVAK 20, VYa 23, NS 37, NS 45
{{Russian and Soviet Aircraft Ordnance 45 mm artillery Autocannons of the Soviet Union Aircraft guns of the Soviet Union Weapons and ammunition introduced in 1944 Aircraft artillery