MG131

[Schwarze_13]

Hi all,

As my first post, I was wondering what the people here think of/know about the MG131:

How much better was the MG131 than the MG17 (besides just the increase in calibre)?

Was the the extra weight and drag worth the extra hitting power gained?

I've read that the hitting power was nowhere near as good as that of the Browning M2 - does anyone know of any ballistics trials/comparisons?

Does anyone know of any pilots' personal opinions of the new MGs?

What sorts of ammo did the MG131 use mainly and how was it usually belted?

Thanks

[Fokker D21]

Read my website: Back to my homepage. The Mg 131 was most likely about twice as strong as the Mg 17 (including rate of fire) and about 70% as strong as the M2 .50 with API rounds.

The drag of the MG 131 reduced the speed of the Me 109 G at sealevel at combat rating (not emergency power) from 492 km/h to 483 km/h. An enlarged streamlined cowling reduced speed only to 489 km/h.

See the website made by Kurfürst: Kurfrst - Influence of the shape the engine cowling on the level speed of the Me 109 G

[HoHun]

Hi Schwarze 13,

>How much better was the MG131 than the MG17 (besides just the increase in calibre)?

Here is a comparison of the total firepower (kinetic plus chemical power) of a couple of aircraft batteries, selected for equivalent firepower and ammunition supply:

 5x MG 151           - 239 rpg - 428 kg -  97% firepower - firepower per weight: 102%
10x MG 131           - 311 rpg - 413 kg -  93% firepower - firepower per weight: 102%
 8x .50 Browning M2  - 250 rpg - 452 kg - 100% firepower - firepower per weight: 100%
25x Browning .303    - 399 rpg - 549 kg -  96% firepower - firepower per weight:  79%
25x MG 17            - 406 rpg - 596 kg -  95% firepower - firepower per weight:  72%

As you can see, the heavy machine guns were about equal in efficiency, even if the heavier 12.7 mm Browning had a slightly higher firepower per barrel and per projectile than the MG 131.

Comparing the MG 17 and the MG 131 per barrel, you'll find that the heavier weapon increased machine-gun firepower by a factor of 2.5.

>What sorts of ammo did the MG131 use mainly and how was it usually belted?

For the above comparison, I used:

MG 151: 1:2 AP:HE
MG 131: 1:2 AP:HE
Browning 12.7 mm: 100% API
Browning 7.7 mm: 1:1 AP:I
MG 17: 100% AP-v

Regards,

Henning (HoHun)

[Fokker D21]

The MG 17 was usually loaded with 5 AP-v, 4 API-v and 1 HEI-v.

It's interesting to see that you rate the MG 17 slightly lower than the .303 Browning. If it's the synchronized MG 17 I agree with you (the difference is small though). An unsynchronized MG 17 is stronger than a .303 Browning because of the "verbesserte" (improved muzzle velocity) projectiles.

[HoHun]

Hi Fokker,

>The MG 17 was usually loaded with 5 AP-v, 4 API-v and 1 HEI-v.

Ah, thanks! Where did you find this valuable piece of information? I've never managed to dig up something like that!

>It's interesting to see that you rate the MG 17 slightly lower than the .303 Browning.

Hm, might be that's simply because I don't have the exact ammunition data for anything but the AP-v round listed on Tony's site. If you have something more detailed than the stuff on Tony's site, I'd love to add it (along with the belting order you suggest) to make the comparison more accurate.

Regards,

Henning (HoHun)

[Tony Williams]

The B.Mk VI ("De Wilde") incendiaries used in the .303 were twice as effective in setting fuel tanks alight as the 7.92mm incendiaries, according to comparative British firing tests.

However, there was in practice very little difference in the effectiveness of rifle-calibre MGs, with the exception of those which were much faster-firing than usual (especially the ShKAS and Ultra-ShKAS, and the MG 81Z).

[Kurfürst]

I guess the MG 131 was simply intended to ractify the problems with 7.92mm calibers which simply lacked the punch the penetrate aircraft armor. The new MG 131 had the neccesary punch, and this was satisfying enough. Also, given its similiar size to the 7.92mm MGs, it could be used as a hand-held bomber defensive gun. IMHO the MG 131 was good solution to a practical problem. Its worth to remember that the 131 was a purpose designed aircraft onboard armament, and the designers appearantly believed that such ballistic properties were aduquate for the task it was being used for, while the US .50 Brownings were simply adaptations of an existing gun that was originally conceived for a completely different task (ground used heavy MG against hard targets like pillboxes and early tanks), where ballistic requirements were much higher. Lower ballistic properties, that were still aduquate for the task were obviously seen as an advantage, the gun was very accurate (35 x 45 cm spread at 100m), and the barrell wore out much less quicky (barrel life of the MG 131 was 17 000 rounds), which meant that ballistic properties detoriated more slowly.

Personally, I`d very much doubt that in terms of damage done, there would be much difference between any of the 12.7mm calibers, regardless of kinetic energy. The more powerful rounds simply made a neater hole in the thin alumiunium skin.. of course ballistics were better with the bigger munition. The MG 131 had OTOH much higher Rate of Fire than the M2 Brownings, and it was much lighter as well. The Soviet UBS was probably the best of the lot, good ballistics, light weight, high RoF.


@Tony,

What kind of 7.92mm incendinaries were used in the British trials? I understand there was one with ordinary phosporus and another with a different type of filling (probably elektrothermite?).

[flojo]

Does anybody know why the Germans did not use the enlarged streamlined cowling on all BF109G but only on the models with bigger supercharger (605D and 605AS engines). It seems not more complicated to produce and mount on an airplane than the bulged version of the DB605A models and offers a speed increase of about 6 kph without obvious disadvantages.

[Schwarze_13]

Originally Posted by Kurfürst

Personally, I`d very much doubt that in terms of damage done, there would be much difference between any of the 12.7mm calibers, regardless of kinetic energy.

I don't want to 'split hairs' but the MG131 was 13mm was it not? Anyway, i get what you are saying about the MGs of that general calibre.

Originally Posted by Kurfürst

The more powerful rounds simply made a neater hole in the thin alumiunium skin...

I would have to agree with you there. But what about shooting things like armoured Plexiglass, damaging engines etc. at greater distances and different angles?

Originally Posted by Kurfürst

The MG 131 had OTOH much higher Rate of Fire than the M2 Brownings, and it was much lighter as well.

However the higher rate of fire was negated (in the single-engine fighters) by synchronisation for firing through the prop

One of my original questions was: Was the the extra weight and drag worth the extra hitting power gained?

The reason i ask - would a lot of fighter pilots not simply have RTB'd as soon as their cannon ammunition was exhausted? Particularly if they were up against the US 'heavies'?

[Fokker D21]

However the higher rate of fire was negated (in the single-engine fighters) by synchronisation for firing through the prop

The Germans used electric priming so synchronisation had less effect on the rate of fire. The rate of fire went form 900 RPM to approx. 810, still higher than the 750 RPM of the M2 .50.

Was the the extra weight and drag worth the extra hitting power gained?

The reason i ask - would a lot of fighter pilots not simply have RTB'd as soon as their cannon ammunition was exhausted?

The two MG 131's together make up less than 30% of the firepower of a 109 (with Mg 151/20 motorcannon). As long as you have 20mm ammo the 131's provide some extra power. When this is depleted you better get home. But if somehow you are forced to engage, two 131's is still a lot better than two MG 17's.

[Schwarze_13]

Originally Posted by Fokker D21

The Germans used electric priming so synchronisation had less effect on the rate of fire. The rate of fire went form 900 RPM to approx. 810, still higher than the 750 RPM of the M2 .50.

Hi Fokker,

I didn't know that - thanks!

(and apologies to Kurfurst )