Defensive & Offensive Armaments

During the 1930s under the restrictions of the Versailles Treaty the newly emerging Luftwaffe was quickly expanding under secrecy and it was in desperate need of arming its aircraft. Around the same time in 1929, Louis Stange of Rheinmetall designed the S.2-200 which later became known as the MG-30. It was a covert German machine gun design that was being secretly produced from 1930 onward in Switzerland by the German subsidized company Solothurn. The MG-30 ended up being rejected by the German army (the Heer), but the Luftwaffe took interest. In 1932 the Luftwaffe ordered Rheinmetall to develop two variants of the MG-30 which would be suited for aircraft use. These variants became known as the T.6-200, which was the defensive turret version equipped with a magazine for gunners of ground attack aircraft, and the S.6-200 which had the capability of being synchronized and belt fed in order to be fired between the propeller blades of the cowling of a fighter aircraft. Given the secrecy of the Luftwaffe at the time, it was decided to give the two variants deceptive weapon model names. The T.6-200 was given the designation "MG-15" and the S.6-200 given "MG-17". The use of these backdated weapon model names was to give the rest of the world the impression that Germany was using shelved weapon designs dating back to 1915 and 1917. This ruse proved to be beneficial when production of these firearms was moved to Dusseldorf, Germany in 1936.

The MG-15, an essentially a lighter weight version of the MG 30, quickly entered production in 1932 and became suitable for flexible weapon station mounts in bomber type aircraft such as the Heinkel He 111. It was also produced under license in Japan and used by the Japanese Army as the Type 98 flexible-mounted aircraft machine gun and as the Type 1 in the Imperial Japanese Navy.

With the outbreak of the Spanish Civil war in 1936, MG-15s were quick to see action. The use of their convenient 75 round double drum magazine gave the gunner an unobstructed view when aiming. However, it soon became evident that with its 1,000 round per minute fire rate, the MG-15 would quickly burn through all the ammunition in its magazines in a matter of seconds. To offset this, gunners were supplied with a large number of magazines and as such running empty on ammunition seldom became an issue. Though with the added interruption of having to reload, opportune moments were being squandered when the gunner could have landed hits on an incoming fighter.

Replacement designs for the MG-15 were already being sought out for by 1935. During the Battle of Britain the it was still the main defensive weapon of choice for bombers, but after late 1940 MG-15s were being steadily replaced by the more capable and belt fed MG-81s and MG-131s. Throughout the war many MG-15s were converted to ground infantry use, the same fate befell MG-81's and MG-131's.

Developed by Mauser in 1938, the MG-81 was designed as a replacement for the Rheinmetall MG-15 which was deemed inadequate even by the mid-1930s. Using their experience from designing the MG-34, Mauser was capable of making the MG-81 simpler, smaller, lighter, and cheaper to produce than either of its MG-34 or MG-15 predecessors. Around this same time during the second halve of the 1930s a new weapon classification system was introduced into the Luftwaffe. Instead of using the convention of naming weapons after their year of adoption into service, the model number would instead stand for the caliber of the round and the models production variant. In the case of the MG-81; the number 81 stands for "1st MG model variant in 8mm" (7.92 being considered 8mm).

At first the MG-81 used a 600m barrel similar to that of the MG-15, but it was considered that the long barrel would cause unnecessary drag at high speeds, creating difficulty for the gunner when aiming. Therefore the barrel was shortened to 475mm, which reduced the muzzle velocity slightly but also increased the accuracy of the weapon. This is because longer barrels reduce accuracy potential due to flexing of the barrel, causing shot dispersion, especially when they heated up and caused barrel distortion from uneven thermal expansion. Additionally, due to the light weight nature of the MG-81 it became possible to obtain an ever higher rate of fire of 1600 rounds per minute, surpassing that of even the MG-42. Another factor that allowed for the increased rate of fire was the new feeding system. One that included a disintegrating metallic-link belt, which could be configured to feed ammunition from either the left or right side of the firearm. All these attributes meant that two MG-81s could easily be paired together to essentially double the fire rate.

This led to the next variation of the MG-81, where two of them were coupled together under one trigger to create the MG-81Z (Zwilling or twin in English). This new variation of the weapon increased the fire rate from 1600 rounds per minute to a combined 3200 rounds per minute.

In the end, as the war went on the fate of the MG-81 did not escape ground service use by infantry. It certainly outperformed the MG-42 in terms of firepower, but without the cold slipstream of air surrounding it, as when mounted within an aircraft, the weapon very quickly overheated. And this paired with the high rate of fire meant a very short lifespan expectancy for the barrel.

The MG-15 is an air cooled, fully-automatic and recoil operated open-bolt machine gun. Utilizing a 75 round dual drum magazine, the gunner has 4.5 seconds of continuous fire before having to reload. You must empty your entire magazine before it is possible to reload. The time to complete the reload sequence takes 6 seconds.

All gunner positions within the He-111 H6 are capable of mounting the MG-15. Ammo capacity varies between gunner positions: Nose Gunner has 600 rounds of ammunition in 8 magazines for 36 seconds firing time, top gunner 1125 rounds in 15 magazines for 67.5 seconds firing time, bottom rear gunner has 1200 rounds in 16 magazines for 72 seconds of firing time, bottom forward gunner has 675 rounds in 9 magazines for 40.5 seconds of firing time, and left and right gunner positions each have 450 rounds in 6 magazines for 27 seconds of firing time.

The MG-81 is an air cooled machine gun and it operates off of an open bolt recoil operated system. It uses a metallic-link belt to feed ammunition from either the left or right into the action of the firearm. This belt then disintegrates coming out the opposite side along with empty casings of 7.92mm rounds that have been fired. For this reason many emplacements of the MG-81 have a collection chute underneath the weapon that collects the disintegrated belt-links and empty cartridge casings so that they may be reused in the future. Thankfully, due the use of a belt, it means the gunner has a continuous uninterrupted stream of ammunition with no need to reload the weapon. The weapon may be recocked through the reload action in case of a misfire, this action takes 1 second.

Only the bottom and side (waist) gunner position of the He-111 H16 are equipped with the MG-81. The bottom of which has an MG-81Z (two MG-81s paired together) each gun having 850 rounds but for a total of 1700 rounds of ammunition, giving the gunner 31.9 seconds of firing time. The side positions feature only a single MG-81 and each have only 500 rounds, giving either of them 18.8 seconds of firing time.

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_7-92x57_apsmk.txt (4.505)

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_7-92x57_apsmk.txt (4.505)

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_7-92x57_apsmk.txt (4.505)

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_7-92x57_apsmk.txt (4.505)

Conceived of in 1913 just before the outbreak of the first World War, the 20mm Becker autocannon served in the Imperial Germany air force from 1916 to 1918. It was mostly fitted in turrets of bombers such as the Gotha but also used in anti-aircraft emplacements. After the war, as a consequence of the Versailles Treaty, production was moved from Germany to Switzerland. In the 1920s the Swiss company Oerlikon eventually bought up the design firm, SEMAG, who was producing the 20mm Becker there. Years later in the 1930s, German arms manufacturers like Rheinmetall and Mauser had several weapons being designed under secrecy through subsidiaries in Switzerland. Some of the designs were promising, others were not, but those that were favorable did eventually get adopted by the Heer and the Kriegsmarine. In 1936 the Luftwaffe was keen on getting an alternative weapons platform to the MG-17s. Ernst Udet in particular saw the age of small caliber rapid-firing machine guns coming to an end. Fighters of the future would need to be armed with more powerful weapons that at the same time did not compromise the flight characteristics of the aircraft. The designs of Mauser and Rheinmetall would not be production ready until the early 1940s. However, in 1935 Oerlikon had perfected the Becker 20mm design and completed three variants of their own based on it. Namely the FF series of 20mm autocannons; the FFS, FFL and FFF. These variants varied in weight, barrel length, fire rate, and muzzle velocity. In 1936, on the suggestions of Udet, the Luftwaffe took the initiative and licensed the last variant, the Oerlikon FFF cannon, which weighed the lightest and had the fastest firing rate out of the three. The Luftwaffe assigned the company Ikaria to redesign and produce the Oerlikon FFF. Ikaria modified the weapon to fire a stronger cartridge that had its caliber increased from 20x72RB to 20x80RB and the barrel was slightly lengthened by 60mm to increase muzzle velocity. The designation given to the weapon by the Luftwaffe became MG FF, standing for "Maschinengewehr Flügel Fest" (Machine gun wing fixed). At the time all fully automatic weapons regardless of caliber were to be considered a machine gun due to the restrictions imposed on Germany by the Versailles Treaty. After the start of the Second World War it was only with the introduction of higher caliber weapons such as the Rheinmetall MK 103 in 1942; that the term "Maschinenkanone" (machine cannon) began to be appear.

Two models of the MG FF knowns as MG FF ausf A and MG FF ausf B were developed; being completed in 1937. The ausf A had a mechanical trigger and was intended to be used in turrets or hand operated gun mounts, while the ausf B had an electrical trigger and was intended to be used within fixed wing or engine mountings on fighter aircraft. Luftwaffe fighters experimented with the installations of MG FF's during the Spanish Civil War, and by the start of the Second World War in 1939 the MG FF had become standard armament on the Bf-109 and Bf-110 series of fighter aircraft. Its use in bombers only became more prominent after 1941, with it being equipped mainly in Fw-200s, He-111s, Do-217s, and Ju-88s.

During the Battle of Britain in 1940 the MG FF proved a very potent weapon when compared to the small caliber machine guns of British fighters. Still, this did not come without notice of flaws inherent in the MG FF's design: The fire rate of the weapon and the initial velocity of the projectile were both too low. Ultimately the MG FF's effective usage was only up to 400 meters, it was considered having almost no practical advantage over regular machine guns. The solution was to introduce a new ammunition that would mitigate this. As a result the "Minengeschoss" (Mine Shell) high explosive round was developed. The principal design behind this new round acted on the fundamentals that the destruction of aircraft structural elements would be caused by the shock wave of the explosion and not the shrapnel. This new "Minengeschoss" round was thin-walled by use of a higher quality steel alloy, which made it possible to increase the explosive charge of the projectile by 20% while at the same time decreasing its total weight. The new projectile weighed 92 grams instead of 115-117 grams as in the old HE shells. A new explosive, Pentrit-A, was also developed which was 1.7 times more powerful than TNT. Later the Pentrite was later replaced by an even more powerful HA 41 explosive. This explosive was characterized by having an increased explosive and incendiary effect. With the addition of new lightweight delayed fuses it was even possible to burst an HE projectile inside of an aircrafts structure, causing tremendous damage underneath the skin to the airframe. To fire this projectile the MG FF firing mechanism had to be modified, rendering it incompatible with earlier ammunition, therefore all modified MG FF's became MG FF/M with the "M" standing for "Modifizierung" (modification). After 1940 the MG FF started being replaced by the faster firing and belt fed Mauser MG 151 and MG 151 / 20; the first one being chambered in 15mm and the latter in 20mm.

A variety of drum magazines were developed for the MG FF, varying from 30 to 45 rounds in capacity meant for use in bomber turrets. Also issued were 60 to 100 round drum magazines for use in fighter aircraft such as the early Bf-109s and Bf-110s; along with the Fw-190 series and later in the Schräge Musik configuration for Bf-110 G4's and other night fighters.

Nations on both sides of the Second World War fielded modified versions of the 20mm Oerlikon autocannon; including the United States, Germany, the United Kingdom, Italy, France, and Japan. The United States in particular produced the most of them out of any other country, using them in the anti-aircraft role on naval ships.

Conceptualized in 1933 and the first prototype built in 1938, the MG-131 was developed by Rheinmetall as a replacement for both the MG-15 and MG-17. The MG-131 was essentially an enlarged version of Rheinmetalls Solothurn MG-30, which itself was the basis for both the MG-15 and MG-17. As with most pre-war firearms research, that done on the MG-131 was of great secrecy. It was imperative to the Reichswehr at the time to give the rest of the world the impression that the German Air Force still only had 7.92 machine guns in service. Their efforts were successful, and the existence of the MG-131 was kept secret until the start of the war. Production of the firearm began in 1940 and it was only until 1941 that the first official manuals for operating and maintaining the machine gun began appearing. As with the MG-81, the naming scheme of the MG-131 follows the convention of caliber of the rounds and then the variant type, with 131 standing for "13mm caliber of the 1st variant type".

Instead of Mausers approach in favoring a higher fire rate (as in their design of the MG-81), Rheinmetall focused on giving the MG-131 more power in terms of the size of the caliber of the round. The 13mm ammunition used within the MG-131 had far greater potential in the warhead types than that of the antiquated 7.92mm ammunition. Use of Panzerbrandgranaten and Sprenggranaten (AP and HE)- Patrone 13mm rounds delivered more of a punch against the ever more armored aircrafts that entered combat as the war continued. However, one drawback of the 13mm ammunition was that it had much poorer ballistics than 7.92mm caliber. The 13mm rounds quickly lost speed and performed much worse the further they traveled. So much so that their principle of effective usage was limited to under 300m in combat. Variations of the ammunition such as the MG-131/8 were created using a 7.92x82mm cartridge to address the issue of the limited effective range of the weapon. While these vastly improved the ballistics, they saw little usage outside of being issued to select bomber aircraft.

A new feature of the MG-131 was that it used electrically primed ammunition. Meaning to fire the weapon an onboard 24-volt power supply of electricity was needed. The reasoning behind this new method of firing the cartridge was to increase the fire rate of the weapon. Although it did slightly improve the fire rate it had more of a benefit in simplifying cowling mounted operations of firing the weapon between the blades of a propeller. Similarly to the MG-81, the ammunition was fed with either a disintegrating or non-disintegrating belt. Likewise the weapon could also feed from either the left or right side; and a Zwilling (Twin) mount of the weapon did appear in certain bomber turrets due to this capability.

Over the course of the war the MG-131 was installed into a variety of aircraft; from fighters, to bombers, and to even transports. It was very plentiful in numbers. Even being installed into armored vehicles as well as being converted to ground infantry use. This was even more the case after the adoption of the MK103 and MK108 30mm cannons in fighter based aircraft. With the availability of higher caliber cannon rounds, the MG-131 was retired from fighter service and saw more of a presence in bomber and transport type aircraft.

The MG FF / M is an air cooled, fully-automatic and gas-operated open-bolt blowback action cannon with Advanced Primer Ignition. Each drum magazine holds 30 rounds, the gunner has 3.3 seconds of continuous fire before having to reload. The magazine must be empty before you are permitted to reload. The time to complete the reload sequence takes 6 seconds.

On the He-111 H6 only the nose and bottom from gunners have the option of equipping the MG FF / M as a modification. For the He-111 H16, the nose gunner position comes standard with an MG FF / M. The nose gunner of both He-111 variants has 240 rounds of ammunition in 8 magazines for 26.6 seconds of firing time. As for the He-111 H6 the bottom front gunner has 330 rounds in 11 magazines for 36.6 seconds of firing time.

The MG-131 is air cooled and operates off of a recoil operated closed bolt system. A metallic-link belt is used to feed ammunition from either the left or right side of the firearm. In the He-111 H16 the ammunition in the top gunner position is fed from the left side; a disintegrating type ammo belt is used and the links drop out the right side of the firearm along with the spent 13mm casings (which are then redirected into a collection chute underneath the weapon). As the weapon uses belt fed ammunition, there is no need for the gunner to perform any reloading. In the event of a misfire, the weapon may be recocked by performing the reload action, this takes 4 seconds as the charging handle is pulled back using a ratchet system.

The top gunner position of the He-111 H16 is the only emplacement on the aircraft that currently uses the MG-131. The gunner has 1000 rounds of ammunition giving him 66.6 seconds of firing time; coming in 2nd behind the H6 with the longest firing time out of any other bomber aircraft within the IL-2 Great Battle series.

• HE Tracer - The same as the M-Gesch.Patr. FFM m.Zerl round above but with a yellow (gelb) tracer charge. Making it [M-Gesch.Patr. Leuchtspur FFM mit Zerleger].

• AP - Armour Piercing Solid (Panzergranatpatrone FFM ohne Zerleger [Pzgr.Patr. FFM o.Zerl]) which can penetrate 35mm of armor at 1 meter, 26mm at 100 meters, 14mm at 500 meters, and 3mm of armor at 2000 meters.

Note: The HE round used in game is in fact a MG FF/M HE/M (high explosive mine shell with thin shell walls) as stated earlier, but within the game it lacks the functionality of a self destruction fuse that can be set for specified ranges. The developers have chosen to omit the customization of this feature.

It should also be noted that within the game both the MG FF/M and MG151/20 use the same projectile, but in real life the cartridges varied slightly. The developers have chosen to share the ammunitions projectile types as they see the difference as negligible (archived).

• AP - Armour Piercing Solid (Panzergranate Patrone ohne Zerleger [Pzgr.Patr. o.Zerl.]) which can penetrate 20mm of armor at 1 meter, 17mm at 100 meters, 8mm at 500 meters, and 1mm of armor at 2000 meters.

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/shell_ger_20x82_ap.txt and IL-2/data/luascripts/worldobjects/ballistics/projectiles/shell_ger_20x82_he.txt (4.505)

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_13x64_ap.txt and additionally at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_13x64_he.txt (4.505)

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/shell_ger_20x82_ap.txt and IL-2/data/luascripts/worldobjects/ballistics/projectiles/shell_ger_20x82_he.txt (4.505)

Source: In the game files located at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_13x64_ap.txt and additionally at IL-2/data/luascripts/worldobjects/ballistics/projectiles/bullet_ger_13x64_he.txt (4.505)