Luftwaffe Cannons and Machineguns topic.

[CharlesBronson]

20x82mm ammo for MG-151/20.



This was the result of the necked up 15mm cartrigde, it was available with brass or steel case, the steel being favored because the always problematic copper resources, more than 80% of the cases wre fabricated in the metal. The ammo for the E variant used a electric primer, the other an standar percusion primer. There was at list 30 variant of projectile for 20x82mm cartrigde including several ubung (exercise) ones, for space reason I will only post the most used in wartime,


Brandsprenggranate glimmspur mit Zerleger.





Explosive-incendiary, with glowing tracer and self destruction fuse, a "working" ammo for the MG-151/20. Bullet weight 115 grams, explosive content 6 grams, the self destruccion device actuate after 1100 meters from the muzzle, o 3 seconds in flight. Muzzle speed about 720 m/s.


Minengesschos.




The thin walled explosive projectile from the FF/M adapted to the MG-151, Weight 92 grams, muzzle speed 785 m/s.


Minengesschos mit Zerleger.



Same as above but with an self destructing device, indicated by a green band stenciled in the bullet. A good decition specially in later war when most of the air combat were fought over the homeland.


Panzersprenggranate.



Armor piercing-explosive, weight 117 grams , muzle velocity 705 m/s. A steel shot with a 5 grams of nitropenta, base fused. Explosive content indicate by a yellow band.


Penetration table por the 20 mm Pzgr. 24 mm at 100 meters (90 º incidence) in 140 kg/squre mm steel, equivalent to a SAE 4140 alloy. The discontinued line indicated penetration after get trough a 3 mm 20 º tilted duraluminium plate.





Panzergranate mit Phosphor




Armor piercing incendiary, filled with an red and white phosphorous mix. 117 grams bullet, muzzle speed 705 m/s.


Panzergranate-Elektron.



AP incendiary, 117 grams, filled with a incendiary mix called "Elektronthermit", the characteristics of this were such as once iniciated it can burn even underwater because it had his own provition of O2. Muzzle speed 695-700 M/s. This variant were used mostly by the maritime and recce aircraft like FW-200C, Ju-88A-14, Ju-290, He-177, Bv-138, etc.

And at last but no at list:

Brandgranate-G-spur.



Completely incendiary ammunition, with tracer, painted entirely in blue. filled with a mix of phosphor and magnesium, 116 grams bullet 710 m/s Muzzle speed. Used with good effect by the night fighters, there was a variant with self-destrution also

[CharlesBronson]

All right time to continue here;

Maschinen Kanone MK-101 de 30mm. Part 1




The search for a gun potent enough to face and defeat bombers with few shots gave as result the delopment of the Rheinmetall MK 101 of 30mm calibre. His development began in 1935 ( simultaneously with other weapons) and in 1940 it was ready to large scale production.


Functioning principle:

The working mechanisns in the Mk-101 is one in wich the barrel and bolt recoiled 3 cm backwards afer the shot. The bolt in locked and open for by a locking sleeve, this sleeve have an internal interrupted treads, and is rotated by and milled lugs in the barrel jacket, the sleeve rotation open and closed the chamber. This system was patented by Louis Stange in the late 1920s and used in some Solothurn MGs like the Mg-29, and Mg-30.

In the Mk-101 gave a strong locking system but a slow rate of fire, about 250rpm.

This 30 mm automatic cannon weights (unloaded) 176 kg, had an overall lenght of 2640 mm, is pneumatically triggered and feeded by a ten-round magazines (which could evidently be changed in flight by the gunner).The 30-round drum was introduced in the Hs 129 installation.

In service:

The Mk-101 was first introduced in the heavy fighter Me-110C-6. There was big plans for this fighter and his armament. Almost the entire production of Me-110C-6 went to the special formation Erprobungsgruppe 210, this group had the task to test special weapons and tactics, ( and teorically introduce the Me-210 in front line service) also it participated in the attacks against the radar station and naval transports of Britain coast. The C-6 had his MG-FF guns deleted to save weight. After some successes the disaster struck the Erpbg 210 formation when it lost his commander Walther Rubensdoffer to the Spitfires.


Me-110C-6 with ventral Mk-101.




The same without fairing.




The surviving aircraft wen to some ZG heavy fighter squadrons

[twoeagles]

This is terrific stuff, CB - I always get an education on this thread.
Thanks! I know this takes some effort.

[CharlesBronson]

This is terrific stuff, CB - I always get an education on this thread.

Oh, Thanks, and yes it take his time to put together all the info, the second part of this tonight.

[CharlesBronson]

MK 101 Part 2, Antiarmor usage.



After the withdraw of action of the Epbr 210 and his aircraft in late 1940 this gun was forgotten more than a year by the luftwaffe, nobody know really what to use for.

However the Mk-101 was seriously consider to the antiarmor use after some test in Rechlin in winter 1941-42. The penetration of the of steel AP bullet was pretty average but with the newly designed H-Panzergranate L-spur the Mk-101 probe to be a winner.

Further test was done in the Kummersdorf tank probe facility against some captured tanks. The MK-101 with tugsten core was devastating against the T-34 .
Just 20 % of the bullets fired on the side plate of a KV-1 penetrated, but the effects the top and engine covers were very effective.

Some pics: effect of MK-101 tugsten ammo in KV-1 heavy tank.










Mk-101 in Hs-129B.



The cannon was introduced in the B-1/R3 subvariant and then used in the B-1 & B-2 until it was replaced by the MK-103. With the MK 101 the Henschel 129 was rised from a mediocre attack aircraft to a powerful close support plataform.

Squematic MK 101 in Hs-129, note the compressed air bottles for charging.




In Hs-129B-2, in manteinance position





In flight position.

[CharlesBronson]

Is worth to mention that this cannon was also used in a double turret in the He-177. Few were converted, one used as a transport to retrieve stalingrad, this aircraft also have the mission to shoot the russian flak emplacement "in the pass"








And was "re-introduced " in some Bf-110Es and employed against tanks in the African desert.




Rheinmetall Maschinen Kanone MK-103



The good results obtained with the MK-101 and his cartrigde caused that the development of a improved weapon.

The new cannon would be more dedicated to the air-to-air combat, because the heavy weight and slow firing of the MK-101 made very inadecuate for that task.

Once again Rheinmetall Borsig put their hand on work and in the late 1942 they had his new design complete.[/font]

The MK 103 used a new system of short recoil with a bolt assisted by a gas to unlock the chamber, a hole in the barrel deviated a small quantity of the combustion gases and move a piston back.

That incremented the speed of the bolt s movement and therefore the rate of fire.

The MK-103 weights 145 kg, had an overall lenght of 2320 mm and his rate of fire was betwenn 380-420 rpm.

There was also a MK 103M variant, that was to be installed in the big V-12 engines like the Jumo 213 and Daimler DB-603. Is worth to note that despite some wrong sources the MK 103 was NEVER put in service with the Me-109K...simply because there was no enough room inside this fighter to put in, for that it would be needed to move the cockpit backwards about 20 cm, and still the gun barrel shall potrude through the Messers nose.

[CharlesBronson]

Edited (repeated post)

[Tony Williams]

Originally Posted by CharlesBronson

Rheinmetall Maschinen Kanone MK-103There was also a MK 103M variant, that was to be installed in the big V-12 engines like the Jumo 213 and Daimler DB-603. Is worth to note that despite some wrong sources the MK 103 was NEVER put in service with the Me-109K...simply because there was no enough room inside this fighter to put in, for that it would be needed to move the cockpit backwards about 20 cm, and still the gun barrel shall potrude through the Messers nose.

To clarify - the MK 103 could not be installed in any Bf 109, but the MK 103M could - it was specifically designed for that. According to Schliephake, one Bf 109K-10 was fitted with the MK 103M for test purposes, but the tests were not successful - I don't know why.

[CharlesBronson]

I think that the nose of the BF-109 was to short for this and it would require some major modifications, If was actually mounted in the K-10 probably several troubles in feeding and everything else.



MK-103 in attack airplanes:

One of the first user of the new cannon was the Hs-129 from the Sch 1 in the Western front, The HS-129 armed in that way arrived to theirs bases in Ukrania in april 1943. This aircrafts had a stunning performance in the big armoured clash of Kursk.

3 images of the luftwaffe groundcrew feeding the Mk-103.

a)- Introducing the belt, note the mix between the Steel AP and Pzg

40.





b) Closing the receiver plate.






c) -In here the technical oficcer adjust the frontal support jack, this absorbed a big deal of vibration and thus increased the gun saccuracy.




MK 103 in Fw-190:

This gun was installed in two containers below the wings. Two types of containes were developed one for the FW-190A-5 and other for the FW-190F-8. The gun in this emplacement was feed by a metallic belts of 32 cartrigdes. It seems that the recoil forces and vibration were too much to the Focke wulf ( despite the strong fabrication of the Wurger wings) and just few aircraft were armed in this way.


FW-190A-5/U11.





Teorically the electric ignition in this weapon allow to shoot through the propellers, however the test with an underbelly MK were a complete failure since the variation in rate of fire caused some "hang" shots, with the predictable consecuences.

[Tony Williams]

Originally Posted by CharlesBronson

I think that the nose of the BF-109 was to short for this and it would require some major modifications, If was actually mounted in the K-10 probably several troubles in feeding and everything else.

Schliephake is the best source I know on the subject of Luftwaffe armament installations, so I trust his account.

The problem with fitting large guns in engine mountings was that there had to be enough space between the back of the engine and the pilot's seat to fit the gun breech and ammunition magazine. The gun barrel wasn't a problem - there was lots of length running from the back of the engine to the prop - as long as it was less than 70mm wide (the diameter of the tube running between the cylinder banks of the 109). The problem with the MK 103 was that there was a gas duct running alongside the barrel for part of its length, and this meant that the barrel couldn't fit in the tube. The MK 103M was redesigned to avoid the need for the gas duct, so the entire barrel could fit within the 70mm tube through the engine.

However, even with the MK103M it would undoubtedly be a very tight squeeze as you say.

[CharlesBronson]

I sought and sought but failed to found a picture of this K-10 variant, The only i ve foud is the K-14 with 3 MK-108 guns.

[CharlesBronson]

MK 103 in fighters:

A Ju-88C night fighter with two MK 103 in a underbelly pod, note the angled barrels.





The 30 mm high velocity gun also was used in some special Me-262 like the Me-262A-1a/U1, it carry a heavy batterie, 2 x MK 108 plus 2 x Mg-151/20 and two more Mk 103 with 70 rounds per gun potruding through the nose. Just 4 or 5 A-1a/U1 were actually deployed, one was used by Heinz Bär.











The Ta-152C was one of the few single engine piston aircraft who could handle the MK 103 between the Jumo 213 V.




The Dornier Do-335 was another, in the B-2 variant also were one Mk-103 embeded in each wing.

[net_sailor]

Originally Posted by CharlesBronson

The 30 mm high velocity gun also was used in some special Me-262 like the Me-262A-1a/U1, it carry a heavy batterie, 2 x MK 108 plus 2 x Mg-151/20 and two more Mk 103 with 70 rounds per gun potruding through the nose. Just 4 or 5 A-1a/U1 were actually deployed, one was used by Heinz Bär.

Probably only three A-1a/U1 were produced.
Heinz Bar used six barell Schwalbe, but this exemplar was equiped with MK 108 (Me 262A-1a/U5 W.Nr. 111355).

Originally Posted by CharlesBronson

The Ta-152C was one of the few single engine piston aircraft who could handle the MK 103 between the Jumo 213 V.

The Ta 152C-3 was fitted with MK 103 (C-0 and C-1 used MK 108 cannon). Tanks in C variant were powered by DB 603L or LA enginies.

Originally Posted by CharlesBronson

The Dornier Do-335 was another, in the B-2 variant also were one Mk-103 embeded in each wing.

Every Pfeil variant had a single MK 103 cannon firing trough propeler hub also.

[Tony Williams]

Originally Posted by net_sailor

Probably only three A-1a/U1 were produced.

I've never understood the rationale behind that installation: the MK 103, MK 108 and MG 151/20 all had significantly different ballistics.

It would have made a lot more sense IMO to combine the MK 103 with the 15mm MG 151, as the ballistics were comparable.

The Ta 152C-3 was fitted with MK 103 (C-0 and C-1 used MK 108 cannon). Tanks in C variant were powered by DB 603L or LA enginies.

Every Pfeil variant had a single MK 103 cannon firing trough propeler hub also.

I'm not clear whether these installations used the MK 103 or the MK 103M.

[net_sailor]

Originally Posted by Tony Williams

I've never understood the rationale behind that installation: the MK 103, MK 108 and MG 151/20 all had significantly different ballistics.

It would have made a lot more sense IMO to combine the MK 103 with the 15mm MG 151, as the ballistics were comparable.

Exactly! This set was introduced on Do 335. Ta 152C-3 had simmilar mix of MG 151/20 and MK 103

Originally Posted by Tony Williams

I'm not clear whether these installations used the MK 103 or the MK 103M.

Good question! There is one Pfeil preserved in NASM. I'm wonder is she still armed and dangerous