Weapons Systems Tech.Discuss USSR Aircraft weapons, 1933-1950. in the Technical forums; Nudelman Suranov NS-23.
1944 design. In order to replace the VYa 23 gun in the new generation of fighters ...
1944 design. In order to replace the VYa 23 gun in the new generation of fighters and shturmoviks, the main objetive in the NS 23 was to increase the rate of fire and to made a gun compatible with synchronization devices.
Nudelman & Suranov adapted their short recoil operation to the new shorter cartrigde giving a increased ciclic rate of fire between 600-650 rpm.
A total control of the firing pin during automatism allowed the cannon to be coupled with interruption gears in single engine fighters.
Its only disandvantage was the reduce muzzle velocity compared with the earlier 23 mm model, however as the NS 23 was not proposed as anti-armor weapon this was felt irrelevant by the VVS. ( as I said before the antitank work was taken in late war by specialized bombs and rockets)
NS 23 compared with the shorter Shvak.
4 x NS 23 in wings, Ilyushin Il-10
The NS 23 was adapted by several late war and post war aircraft such as: MiG-9, Yakovlev Yak-7U, Yak-9U, Yak-15, Yak-17, and Yak-23 Il-10, Il-18, Il-20 ( fixed) Lavochkin La-9 and La-11 ( synchro) and defensive in Ilyushin Il-22.
The manufacturing of NS 23 ended in 1950.
Il-22 rear emplacement.
NS-23 characteristics:
Action: short recoil rotating bolt head. Counterrecoil by helicoidal spring and Hydropneumatic cilinder.
Charging: pneumatical
Lenght: 2230 mm
Weight: 37 kg
Rate of fire: 600-650 ( 500 rpm in La-9 and La-11)
Muzzle velocity: 685-710 m/s
3 x NS 23 in the nose (lavochkin La-9)
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Last edited by CharlesBronson : 10-21-2008 at 06:36 PM.
The NR-23 is basicly a modified variant of the NS-23. The objetive was to increase the rate of fire.
The engineer Richter ( also quote as Rikhter in some sources) was the responsible behind the mechanical "accelerator" introduced in this cannon. The accelerator is a piece used in automatic armament wich increases the speed of bolt movement. Obviously that also incresed the rate of fire wich is about 750-800 rpm.
The NR 23 shot the same cartrigde as the NS 23 and was the armament used in Mig-15, Mig 17. early Mig-19 and also as defensive gun of IL-28 and Antonov An-10.
In the bombers emplacement it have a steel bracing to reduce the aerodinamic flutter.
Its barrel is slightly longer than NS 23 and the counterrecoil spring is cover by cilindrical metal sheet.
Charles, do you happen to know how much the installation of the NS-37 or NS-45 increased the weight of the YAK-9? I imagine there was some extra bracing as well as the gun + ammunition.
Charles, do you happen to know how much the installation of the NS-37 or NS-45 increased the weight of the YAK-9?
for some 150 kilograms. That's why the fuselage was bulkheaded and the canopy was moved backwards to maintain an acceptable center-of-gravity value. Yak-9T had some 160 kg of fuel less than its predecessor because of the same reason as well.
In a similar way as the NS 23 the main objetive requesting the design of the N-37 was to deliver a 37mm explosive shell with higher rate of fire than the earlier large caliber OBK-16 guns.
The principle of automatism was the trusty short recoil with a rotating head to lock the chamber. N-37 shoot from a open bolt, meaning that every time the trigger was depressed the bolt advance over the ammo belt extracting a cartrigde, introducing it on the chamber and firing after the later was closed.
N-37 used a modified 37mm cartrigde with shorter case wich reduced muzzle velocity but decreased recoil and allowed a lesser weight compared with NS 37
First prototype of this gun was ready in april 1944, and it was put inside a Yak-9T with good result. In august of the same year the gun was taking operative state with the harder job beign setting properly the "hardness" of fuzes in HE ammunition ( with the early used 37x195mm amunition sometimes the shell didnt explode hitting soft ground) Following test were airborne inside a MiG-9.
The Mikoyan Gurevich MiG 9 was the first operative Jet aircraft of the VV-S and it was equipped with two RD-20 ( copy of german BMW 003 engines) the N-37 was located between the "lip" dividing the airflow for both engines.
This location had some troubles however. Shooting at high altitude the unburned gunpodwer and combustion gases sucked in by the Klimov engines caused flameouts.
Modifications were introduced in the shape of a muzzle brake wich provide some dispersion for the gases, this cured the situation in some extent but the maximum altitude in wich the MIG 9 could used its big cannon was limited to 8000 meters. The gun modified in this way was denominated N-37D.
For the new MiG 15 the designers placed the N-37D below the air intake and paired with a couple of NS-23 (NR-23 in Mig-15bis) all togheter in a nose pack wich could be dismounted quickly for resupply of ammunition and maintenance.
N-37D/NR-23 pack in the MIG-15bis.
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Last edited by CharlesBronson : 10-21-2008 at 06:40 PM.
The N-37 had the opportunity to enter quickly into combat due to the Korean conflict of 1950-53.
In there it showed a demolishing power against the formation of USAF bombers and its escort fighters.
Nevertheless due to the little ammunition capacity the burst was of short duration (6.1 seconds) reason why the pilot had to be to be careful with his use, also the cadence was not suitable to fight against a jet fighter in maneuvers of high speed since easily a F-86 could get “in between” the shots .
A thing is certain, the combination of guns of the Soviet fighters gave them enough and superior firepower compared with the sixgun configuration of machine guns of the F-80/84/86, several MiG-15 returned to home with a large number of impacts of caliber 12,7mm in its fuselage whereas the Fighters of the UN could not repeat the feat after being hit powerful Russian guns.
For the heavy fighters Yak-25/27 it was adopted a denominated variant N-37L, this airplane mounted two guns with a belt feed of 100 cartrigdes.
The Yak-27 used a longer barrel variant designated NN-37L, its longer tube increased muzzle velocity to 700 mps.
19,500 units of N-37 were manufactured between 1947 and 1960.
Characteristics:
Calibre: 37 x 155 mm
Automatism operation: Short recoil, rotating bolt, pneumatically charged.
This a rarity, the only information I found about this gun is it used the same ammunition of the NS-23/NR-23 and had a increased rate of fire to 800-900rpm. I cant find a close up photo or squematic of the mechanism but being a Shpitalny design my guessing is it was gas operated.
It was put in a Yak-15 prototipe and in a very interesting pivoting emplacement in the Mig-15Su, experimental variant of 1950. The standard quick-change armament pack housing one 37mm and two 23mm guns was replaced by a fixed installation of two powerful Sh-3 23mm guns, each with 115 rounds.
MiG-15 SU
Each gun was mounted below the fuselage in a streamlined fairing. The barrels projected through a vertical slot so that, mounted on trunnions and driven by an irreversible electric screwjack, it could be elevated to +11° and depressed to -7° (there was no lateral movement). The Ministry order for this conversion was signed on 14th September 1950, and the SU was factory-tested between 2nd January and 27th March 1951.
Official VVS testing followed from 30th June to 10th August 1951. The general opinion was that in tight turning combat the system was useful in bringing the guns to bear, and it also enabled a head-on attack to be made with less risk of collision. The concept seemed to have merit, but it was not adopted for production.
I forgot the post with information about the N-37 ammunition, so :
37x155mm ammunition:
Cartridge cases are brass and filled with 127g of 4/1 FL propellant, they use the same percussion primer as the 45mm antitank rounds use. Maximum armor penetration of the AP shell was 50mm.
20 cartridges of older manufacture were packed in a wooden box and separated by wooden spacers, these boxes weighted 40kg. Later, 10 cartridges were packed in a sealed metal container and 3 of those containers were overpacked in a wooden box weighting 56kg. Cartridge belt links are packed in 400 pieces separately in a wooden box that weighted 60kg.
Ammunition was manufactured by the Czech Republic, Poland and Russia.
OZT: HEI-T 735 670 Conventional HEI-T shell filled with 37g of HEI, self-destruction nose fuzes A-37, A-37U or B-37 fitted
OFZ, HEI 729 670 As above but without tracer and filled with 49g of HEI
BR: APHE 734 670 Base fuzed APHE shell filled with 36,1g of HE, AD-37 base fuze
BZT: AP-T 735 670 Pointed AP shell with ballistic windshield cap (no incendiary!), tracer element is sometimes not fitted
This type is also used as TP-T training round UB-37 TP Airburst 726 670 As HEI shell but with self destruction fuze without impact action, light blue colored fuze tip. For aerial target practice, self destructs between 9 and 12 sek.
Interestingly enough there was also a Yak-3 variant wich used the 45mm gun, the Yak-3K, the russian source in very laconic about its destiny "...was not in series production".
Probably suffered the same structural and recoil troubles of its NS 45 armed bigger brother.
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Last edited by CharlesBronson : 09-29-2008 at 07:33 PM.
There was several entusiast of the recoiless gun in the USSR as early as 1918. The major exponent in the period of time we are interested was L.V Kurchesvskiy, engineer who designed several types with calibres varying between 45 up to 152mm
The principle was invented by the Colonel Davies of the US navy in 1916. Using the actioan and reaction principle the gun need to launch a counterweigh with the same mass and speed to eliminate the recoil.
The RG weapons had the advantage to use a large caliber tube thus a large caliber shell wich could be fired from a relatively small aircraft.
It disavantage is that even today is difficult to obtain a reliable working automatic mechanism.
In the next post I will give a review of the Kurchesvskiy guns and the aircraft armed with those, most of them for experimental purposes.
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Last edited by CharlesBronson : 10-01-2008 at 08:12 PM.
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