Luftwaffe Cannons and Machineguns topic.

[CharlesBronson]

For the armament fanatics like me, this topic related to the barrel armament in service & development with the German air Force.

[CharlesBronson]

Rheinmetall Mg-17 calibre 7,92mm.


As we already know the stiff regulation of the Versailles treaty had a serius effect on the german guns manufacturing after WW1. With most of the early desing destroyed or captured the newly created Luftwaffe had to provide itself with new weapons, with were no related with the olders ones, a very favourable thing.

The first new desing was the rifle caliber Mg-17 wich was introduced in the biplane Fighter Arado Ar-65 in mid 30s, later it saw service in the Ar-68, He-51 and the legendary FW-190s and Bf-109s.





The weapons is adopted for fixed mountings only.Is feeded by a desintegrable metallic belt and It work for the short recoil principle: the barrel and the lock recoil soem milimeters back after the shot and then the brech became open. The Mg-17 used a mecanism called "locking slevee" wich was a interrupted threaded ring wich, it open and close the breech used the linear alternative movement. This kind of mechanic action was used in some early Rheinmetall and Solothurn desings like the MG-29 and MG-30. To increase the rate of fire the muzzle had an gas trap wich efectively turned back a portion of the bullet propelant and accelerate the lock movement.

The gun had a cyclic rate of fire of 1160 rpm, droping at nearly 1000 rpm in sincronizated mountings like the ones in the german single engine Fighters.

Twin MG-17 in FW-190A-1 cowling, note the side eyection chutes for the links and cases.




This MG is phneumatic triggered, it weights 12 kg, have an overall lenght of 1150 mm (600 mm barrel). Despite being designed for fighters some were used in fixed mounting in bombers and attack planes like the He-111 and Ju-88. this was used as a defensive device, even it was more a psicological weapon.

"Scary mounting" fixed Mg-17 in the He-111 s tail.





Nose layout in a Me-110, 4 x Mg-17:

[CharlesBronson]

Another pic of the fixed Mg-17.

[CharlesBronson]

Rheinmetall MG-15, flexible gun.

Having already a fixed 8mm machinegun, the engineers in the newly created Rheinmetall-Borsig sought a flexible Mg with similar characteristics.
( Borsig was a very qualificated metallurgic plant wich merge his facilities with the steel and weapons gigant Rheinmetall in 1936).

The new MG 15 used the same recoil principle of the earlier MG 17 but with simplificated construction. it was also lighter with 7,3 kg in weight ( unloaded). The barrel was 595mm long, the overall length 1100 mm. The smaller muzzle gas trap means that the cliclic rate disminished a little, roughly 1000 rpm.

MG 15 and "saddle magazine"



One bad characteristics of this weapon is the fed device...completely unable to handle the metallic belt.
In full automatic fire the gunner had to change the 75 round magazine after 4,7 seconds.

Inner squematic showing the recoilling barrel, chamber and the powerful counter recoil spring.




MG 15 in Fw-189.





Some MG 15s were converted in ground light machineguns, using a Mg-34 tripod and a metallic shoulder stock, most of these were used for the Fallschirms, Luftwaffe ground units. a smaller numbers reached the Heer.

Converted MG-15 in use by the Afrika Korps.

[Denniss]

Nice images.

But please use the correct syntax MG 15 and MG 17 as well as Arado Ar 68 or Ar 68. There's no "-" between the designations. It is only use for subversion designation like A-1, A-2, B-1 etc but not between manufacturer name, manufacturer code and RLM type number (only a space inbetween). Thus Focke-Wulf Fw 189 A-2 or Fw 189 A-2 but not Fw-189A-2.

[CharlesBronson]

Fine..is just that i have seen the "-" in several sources.


Mauser MG 81.

The effectiveness of a rifle caliber machinegun has been always marginal. To increase the chances to bring down ( or at list seriously damage it) an aircraft with this small weapons a high rate of fire is needed, that ad an sumatory effect of multiple the hits.


Mg 81Z in FW-189A-2.




The german response for this was the Mg 81. This Mauser desing used a short recoil mechanism based on the MG 34 s one. The system was more simple than the Rheinmetall weapons , the barrel and bolt go backward just 5mm after shooting, and the unlock begans, the breech was open and closed for means of an rotating bolt head. This locking was a very fast one. The gun was provided with a muzzle trap with help the recoil forces, the barrel was considerabely shortened to made the ciclic operation faster thus increasing even more the rate of fire. The charging mechanism was manual.


MG 81 inner squematic, note the muzzle gas trap and the powerful spring.




As result of all this the MG 81 could reach the 1500-1600 rounds per minute according to the ammo used. The rate of fire was considerable in a single but most of the manufactured Mg-81 were used a the double weapon MG 81Z ( Z= zwilling= twin). In this 2 MG 81 were coupled in a single trigger. That provide a weapon wich can shoot well over 3000 rpm.

[CharlesBronson]

MG 81 ( continue from above)

Another serious advantage over the MG 15 was his feed system, a desintegrable metallic belt. Ussually a 1000 round link was used per gun tube. The MG 81 was used in several tipes of bombing and recce aircraft like the Ju-87D, Ju-88, He-177, Ju-188. Ar-196, Fw-200 etc.

Armored turret KS-81 in Ju-87D-3.





MG-81J single barrel in Ju-88A-4.





The Ju-87D and the attack variants of the FW-190 could mount a WB-81Z below the wing to engage enemy infantry , this contain 3 MG-81z tilted down 32 degrees so the aircraft shoot downwards even in level flight, this layout unleash a rate of more than 6000 rpm... ¡¡¡ quite a Minigun.

WB-81Z




A more weird weapon was the MG 81 converted for ground role. Is not clear if the huge rate of fire was reduced to this, is know that several were put on servise with the Luftwaffe Ground Units.







MG 81 characteristics (single barrel):

Calibre : 7,92x57 mm

Weight: 6,3 Kg.

Barrel lenght: 47 cm.

Overall Lenght: 94,5 cm.

Clclic rate of Fire: 1500-1600 dpm

Muzzle speed: 810-850 m/s.

[CharlesBronson]

The 7,92x57 mm ammo.




Teorically the family of 8mm caliber MGs were capable of shoot every tipe of cartrigde with the exception of the reduced charge Nahpatrone.

However a special ammo was created for aerials weapons, that was the Vervesserte (improved) cartrigdes o "V" patronen.

The V cartrigdes were provided with 15 % more powder charge, that aumented the muzzle speed well over 800 m/s shortening the flight time to target. The increased pressure also help to move the heavier recoil spring used in aeronautical weapons compared with ground MGs.

The selected proyectiles to be used was: P.m.K ( Phosphor with steel core, an API bullet) S.m.K (Pointed with steel core, AP bullet) and the complicated "B" patrone ( Beobachtung= observation ,an explosive incendiary round) this B bullet detonated on impact and was an alternative to the tracer.

B-patrone bullet before and after impact.



All this cartrigeds can be combined with day (L-spur) or Night (Glimmspur = Glowing) tracers.

Below a table of the cartrigdes used and his Muzzle speed:





Bullet markings for the high pressure V ammo:




The armor piercing round penetrate 10 mm steel plate at 100 meters in a 90 degrees angle.




This cartrigdes were told to not be used in the standar infantry weapons, nevertheless some soldier of the Luftwaffe do it , the strong K-98 action withstand the V bullets without any trouble.

[CRASHGATE3]

Interesting stuff
Thought you might like to see these taken at Cosford museum a few weeks ago

[CharlesBronson]

Nice image, you actually can see the rifling in those MKs, thanks.

[Tony Williams]

Originally Posted by CharlesBronson

However a special ammo was creted for aerials weapons, that was the Vervesserte (improved) cartrigdes o "V" patronen.

The V cartrigdes were provided with 15 % more powder charge, that aumented the muzzle speed well over 800 m/s shortening the flight time to target. The increased pressure also help to move the heavier recoil spring used in aeronautical weapons compared with ground MGs.

Actually, the v-Munition (spelled verbessert) generated more recoil than the standard MG 17 could handle, so a specially modified version of the gun was developed, which would then not work with ordinary ammo. Barrel life was reduced to 2,000 rounds, as the high-pressure loadings were much more erosive.

Tony Williams: Military gun and ammunition website and discussion forum

[lesofprimus]

Did they continue to use the modified gun and ammo then???

[Tony Williams]

Originally Posted by lesofprimus

Did they continue to use the modified gun and ammo then???

I believe so - I think that the Bf 109 and Fw 190 probably used them until the 7.92mm guns were replaced by the MG 131.

Tony Williams: Military gun and ammunition website and discussion forum

[lesofprimus]

I thought that was the case, but u as the resident expert would know better than me... Thx..

[CharlesBronson]

Actually, the v-Munition (spelled verbessert) generated more recoil than the standard MG 17 could handle, so a specially modified version of the gun was developed, which would then not work with ordinary ammo.

It had not much sence to use the normal ammo in those guns aniway.


Rheinmetall Borsig MG-131 part 1:



Following a direct order from Göring staff, the Rheinmetall firm was again in charge to develop a new weapon, this time a medium calibre MG. The work began in 1935 but made little progress until early 1939 when the the german technicians finished this 13 mm gun.

This was a belt feed, air cooled, it weights 17,5 kg and shoot at 930 rpm (non-sincronizated). The feeding system was interchangeable for left or right feed with only minor parts changing.

This weapon also used the short recoil mechanism , the barrel actually go back some 19 milimeters and then the bolts lock is disengaged. As in the MG 17 a gas trap aided the recoiling part in order to improve the rate of fire. This mechanism of recoil plus a locking sleeve was patented by Louis Stange in 1933 and slightly changed for the use in this caliber.


MG 131 for flexible mountings.




This machinegun deploys a very compact desing with its barrel just 593 mm in lenght and a light weight considering the half inch caliber, however that prerrogatives brings some limitations, the cartrigde case was short compared with those used in the U.S Browning M2 .50 or the Russian Berezin UB de 12,7x108mm.

Nevertheless it was a more reliable weapon and it had a higher rate of fire than the american M2. This weapon was first introduced in limited numbers in November 1940. The first aircraft in wich saw some service was the bomber Do-217E , it carry a couple of flexible guns one in a ventral turret and other in a powered dorsal turret.

In the fighters was introduced in the Bf-109G-5 and the Fw-190A-7. Originally the Fw-190A was designed to carry a MG 131 in each wingroots, it was tested in some prototipes but none A series carry this armament being replaced by a MG 17 and then for a heavier MG 151/20 cannon.

MG 131 in Fw-190V5 wingroot.




The 131 gun was put into service in great scale in 1941, replacing and complementing the 8 mm MGs in aircraft such Fw-200, Ju-88, Ju-90. Ju-290, Ju-52. etc.


The "eyes", double MG 131 mounting behind armored glass in the rear Ju-88A-4 cockpit.