Mauser MG 213

[GrauGeist]

So would just a couple of regular 20mm cannons have been effective to begin with?

I would say that the MG151/20 would have been a much better weapon in fighter-on-fighter confrontations. It packed a heavy punch, it was lighter than the Mk108 while being slightly longer, it had a better rate of fire and most importantly, it had a far better range (800m) than the Mk108.

Even the He280 was designed for the MG151/20, and was armed with three in the nose.

 

[DerGiLLster]

I would say that the MG151/20 would have been a much better weapon in fighter-on-fighter confrontations. It packed a heavy punch, it was lighter than the Mk108 while being slightly longer, it had a better rate of fire and most importantly, it had a far better range (800m) than the Mk108.

Even the He280 was designed for the MG151/20, and was armed with three in the nose.

So are you saying that any Gatling type gun would be useless to even start with? I am not disagreeing with your statement, I find it to be very plausible, I just need you to affirm that the Gatling gun would not be very useful as it would have promised.

 

[Shortround6]

If you drop the rate of fire of the Gatling down to 2000rpm it looses just about all it's advantage in that it weighs 2-3 times what a normal 20mm gun does. SO an equal weight of normal guns will put out about the same volume of fire. The Molins company of England Hispano up to 1000rpm. Molins was the company responsible for for the feed system on the 57mm gun in the Mosquito. The conventional guns usually don't need extra electric booster motors in the feed system and don't need either electric or hydraulic power to run the gun.

BTW the R4M rocket was another "gee-wiz" weapon that didn't work out as planed. It actually couldn't keep the fighters out of the range of .50 guns on the bombers and was wildly inaccurate. It lived on in much improved form as the soviet 57mm rocket system. French and British tried 2in rockets in the 50s and the US tried 2.75in rockets. After years of work everybody went back to guns or changed to guided missiles for air to air work.

 

[johnbr]

For the ones that do not now the Me-262 was tested with the mg-213.But the test papers lost in a train fire.

 

[DerGiLLster]

Shortround6, what do you think would have been an effective weapon configuration for the Me 262. Do you think that the idea of a Gatling gun was limited to only paper in the Second World War?

 

[Shortround6]

Just to make sure we are on the same page, The US M39 cannon used in the 50s-60s was a revolver cannon (one barrel, multiple breechs) and weighed about 81kg and fired at around 1500rpm, later guns were faster. The M61 Vulcan gun firing the same ammo went 114-125kg and fired between 3000-7200rpm depending on model and application. The 7200rpm was rare.
A 3 barreled version for helicopters went about 66kg but rate of fire was restricted to 750rpm.

During the early 50s the Navy managed to get a modified Hispano (called the MK 12) firing lower powered ammo than the Air Force guns up to 1000-1200rpm for a weight of 46 kg. Reliability was a problem.

There are two kinds of recoil, peak recoil or the max amount per shot and cumulative recoil. All the recoil impulses over a given period of time. This may be one reason the Helicopter rate of fire was held down. the gun was in a trainable turret and high recoil forces applied off center to the helicopters axis could cause it to slew off target.

Each type of gun has advantages and disadvantages and the fast firing guns took quite a while to mature. The basic idea may be simple but getting them to work reliably (not jam or not break) is what took up the development time.

 

[Shortround6]

Shortround6, what do you think would have been an effective weapon configuration for the Me 262. Do you think that the idea of a Gatling gun was limited to only paper in the Second World War?

I think the Gatling gun was pretty much paper only. You have to be able to feed it for more than a second or two and it needs external power. Either a big electric motor or a big hydraulic motor. The M61 Vulcan needed about 35hp to drive the gun and the linkless feed system finally adapted. Early experiments with belted feed had problems with broken links, stretched links and kinks. Getting the 'host' aircraft to provide the power is another problem. You need a hydraulic pump on the engine (or on one engine) capable of providing the power or a generator and battery setup capable of providing the power. Even if you fire slower and cut the power consumption in 1/2 that is around 13000 watts. even at 28 volts that is 466 amps which needs a good generator (or a good battery) and big cables.

Getting the gun to fire on a a ground test stand for 50-150 shots is easy. Getting it to fire while pulling a 3 G turn and supplying it with 6-10 seconds worth of ammo is the hard part.

 

[davebender]

MG151/20 cannon. 42.7kg. 750rpm. 805 m/s. 18.6 grams of HE filler in shell.
2cm Flak38. 57.5kg. 480rpm. 835 m/s. 22 grams of HE filler in shell.

85 m/s greater velocity plus projectile 1/3rd heaver results in considerably improved long range hit probability. This allows enemy bomber boxes to (hopefully) be engaged outside effective range of their defensive machineguns. 20mm x 138mm cartridge is considerably more powerful then typical aircraft 20mm cannon rounds. They will hurt even against heavy bombers.

Why not a belt fed 2cm Flak38 for heavy fighter use? Long range capability for use against bombers and lethal to enemy fighter aircraft. Weapon weight almost identical to low velocity 3cm Mk108 cannon.

 

[tomo pauk]

Three Flaks weight as much as four MG 151/20. Combined RoF is 1440 vs. 2800 rpm (Tony Williams gives 700 rpm for the MG 151/20). I'm not sure that Flak will provide anything above vs. the mg 151/20.

Now - if we neck-out the Flak cartridge to 23-24mm, so the Mine shell of, say, 200 g is fired, and RoF is upped at at least 600 rpm, in a gun with belt feed...

 

[GrauGeist]

So are you saying that any Gatling type gun would be useless to even start with? I am not disagreeing with your statement, I find it to be very plausible, I just need you to affirm that the Gatling gun would not be very useful as it would have promised.

Here is a scale comparison between the Mk103, Mk108 and the MG213. Note that the MG213's size falls between the 103 and the 108.

However, we're back to the 30mm versus the 20mm question. The 20mm round is certainly effective against enemy fighters and in the fighter role, the Me262 could well have used the 20mm to good effect. A battery of four MG151/20 would have had range, hitting power, adequate ammunition stores to make it a potent contender.

It's true that a 30mm minengeschoss round would tear the wing off of a P-51, but that is complete overkill, considering the 20mm would do considerable damage in it's own right.

To give you an idea of how much room is really available in the nose of the Me262, here is a diagram of the Me262A-1a/U1 and how the MK103, Mk108 and MG151/20 were fitted. Note the limited area for ammunition storage that's packed around the nose-gear bay. Also, the MG151/20 barrels and the Mk103 barrels were protruding, which caused a noticeable buffeting effect while in flight. If the MG151/20 were placed where the Mk103 is shown (C) and the Mk108 is shown (A), then the barrels would be embedded, thus avoiding the buffeting. There would also be more storage area for the ammunition - the increased weight of the ammunition and the lighter weight of the MG151/20 falling within the historical design load of the MK108 ammunition.

 

[Shortround6]

You also have to remember Newton's 3rd law. If you fire heavier projectiles at higher velocity you get more recoil. Granted the heavier gun damps this down a bit but then Mr Benders information is off more than just a bit. The Flak 38 fired similar weight projectiles about 200 meters faster than the MG 151. They may have loaded down the high capacity Mine shell due to the thin walls, just a guess but why the mine shell would be fired about 65 ms a second slower than the thick wall shell I don't know.

You also have a problem with the belt feed, it will slow the gun down as it takes power to operate the feed. The Flak 38 was recoil operated. Please look at the Hispano which was a hybrid. gas unlocked it but there was also a recoil component. Hispanos with a muzzle brake almost always feed from the drum. They took the muzzle brake off to get enough power to operate the belt feed. Also please note that the Flak 38 used a cartridge case 56mm longer than the MG 151 which means, assuming the same length projectile (or same length sticking out the case mouth that the bolt has to travel 56mm more each way per round fired. even at 450rpm that is an extra 50+ meters of bolt travel per minute over a MG 151 firing at 450rpm.

The Hispano used a 110mm case.

I am also truly amazed that the Flak 38 with about 47,000 joules of muzzle energy (119gram projectile at 900m/s) is such a devastating weapon firing at 450-280rpm cycle rate (not including magazine changes) and yet the Hispano with 50,300 Joules (128-130gram projectile at 880ms) and firing at 600rpm is almost considered an also ran.

You want a good alternative armament for the Me 262? Stick four belt fed Hispanos in the nose. Perhaps not as dangerous to bombers but you aren't going to get much better for fighter vs fighter in late 1944.

 

[DerGiLLster]

MG151/20 cannon. 42.7kg. 750rpm. 805 m/s. 18.6 grams of HE filler in shell.
2cm Flak38. 57.5kg. 480rpm. 835 m/s. 22 grams of HE filler in shell.

85 m/s greater velocity plus projectile 1/3rd heaver results in considerably improved long range hit probability. This allows enemy bomber boxes to (hopefully) be engaged outside effective range of their defensive machineguns. 20mm x 138mm cartridge is considerably more powerful then typical aircraft 20mm cannon rounds. They will hurt even against heavy bombers.

Why not a belt fed 2cm Flak38 for heavy fighter use? Long range capability for use against bombers and lethal to enemy fighter aircraft. Weapon weight almost identical to low velocity 3cm Mk108 cannon.

davebender, didn't the flak38 weigh close to half a ton or something like that? It would be great if the Luftwaffe had applied it to the Me 262, but I always thought the gun itself was too heavy to be used on the Me 262.

 

[DerGiLLster]

You also have to remember Newton's 3rd law. If you fire heavier projectiles at higher velocity you get more recoil. Granted the heavier gun damps this down a bit but then Mr Benders information is off more than just a bit. The Flak 38 fired similar weight projectiles about 200 meters faster than the MG 151. They may have loaded down the high capacity Mine shell due to the thin walls, just a guess but why the mine shell would be fired about 65 ms a second slower than the thick wall shell I don't know.

You also have a problem with the belt feed, it will slow the gun down as it takes power to operate the feed. The Flak 38 was recoil operated. Please look at the Hispano which was a hybrid. gas unlocked it but there was also a recoil component. Hispanos with a muzzle brake almost always feed from the drum. They took the muzzle brake off to get enough power to operate the belt feed. Also please note that the Flak 38 used a cartridge case 56mm longer than the MG 151 which means, assuming the same length projectile (or same length sticking out the case mouth that the bolt has to travel 56mm more each way per round fired. even at 450rpm that is an extra 50+ meters of bolt travel per minute over a MG 151 firing at 450rpm.

The Hispano used a 110mm case.

I am also truly amazed that the Flak 38 with about 47,000 joules of muzzle energy (119gram projectile at 900m/s) is such a devastating weapon firing at 450-280rpm cycle rate (not including magazine changes) and yet the Hispano with 50,300 Joules (128-130gram projectile at 880ms) and firing at 600rpm is almost considered an also ran.

You want a good alternative armament for the Me 262? Stick four belt fed Hispanos in the nose. Perhaps not as dangerous to bombers but you aren't going to get much better for fighter vs fighter in late 1944.

Shortround6, how did the Luftwaffe counter the bombers? I know for a fact that the P-51D's were superior fighting machines to any German piston plane in 1944. Would the mass producing of the Me 262 with four Hispano cannons have driven the P-51D fighters out the sky? That would make the B-17's easy meat then.

 

[DerGiLLster]

Here is a scale comparison between the Mk103, Mk108 and the MG213. Note that the MG213's size falls between the 103 and the 108.

View attachment 292591

However, we're back to the 30mm versus the 20mm question. The 20mm round is certainly effective against enemy fighters and in the fighter role, the Me262 could well have used the 20mm to good effect. A battery of four MG151/20 would have had range, hitting power, adequate ammunition stores to make it a potent contender.

It's true that a 30mm minengeschoss round would tear the wing off of a P-51, but that is complete overkill, considering the 20mm would do considerable damage in it's own right.

To give you an idea of how much room is really available in the nose of the Me262, here is a diagram of the Me262A-1a/U1 and how the MK103, Mk108 and MG151/20 were fitted. Note the limited area for ammunition storage that's packed around the nose-gear bay. Also, the MG151/20 barrels and the Mk103 barrels were protruding, which caused a noticeable buffeting effect while in flight. If the MG151/20 were placed where the Mk103 is shown (C) and the Mk108 is shown (A), then the barrels would be embedded, thus avoiding the buffeting. There would also be more storage area for the ammunition - the increased weight of the ammunition and the lighter weight of the MG151/20 falling within the historical design load of the MK108 ammunition.

View attachment 292590

GrayGeist, I love the image you attached! These posts just keep getting better and better!

Hey what if the Me 262 had six MG 20 cannons in it's nose? Could it have pulled it off? Couldn't the Germans perhaps have used some titanium and aluminum to decrease the weight of the cannons? I understand the titanium would have increased the price of the cannon by several fold at least, but with a reduction in weight of about 20-30%, wouldn't it have provided the weight for the Me 262 to lift the cannons?

 

[Shortround6]

I think you are working on a pipe dream. There is nothing the luftwaffe could have done short of coming up with a science fiction death ray and a plane that could be flown by not very bright and rather clumsy 14-15 year olds that would have stopped the American bombers in 1944. North American was building about 700 Mustangs a month. They were building about 500-600 P-47s a month and 3-400 P-38s, granted some were going to the Pacific but the chances of the Americans running out of fighters was pretty slim (throw in the British fighters and there was no chance).
People have been arguing for decades (and will argue for decades more) if the P-51 was the equal of certain models of the Fw 190 ( and few will push the 109K) but the main problem was that on average the American (and allied) pilots of 1944 were better than the German pilots of 1944. The Germans had their 'experten" but they were running out of them and the replacement pilots just didn't have enough training for more than a very few to survive their first combat missions. Sticking them in jets wasn't going to change things enough. The Germans weren't going to be able to play a war of attrition with the allied fighters and shoot down so many that the Americans would run out of fighters and send over bombers unescorted. They would simple wait a few weeks until another few hundred fighters were delivered.

The Germans only chance was to bypass the fighters and try to kill enough bombers (4 engines and 10 men are harder to replace than one engine and one man) so the Americans would stop/pause and rethink the bombing campaign.

The four 30mm cannon in the 262 was about as good as it was going to get for killing bombers. With average pilots getting about 2% hits of rounds fired the 262 carried enough ammo for 1-2 kills on 4 engine bombers. if you needed 15-20 20mm hits and only got 2% hits you need 720-1000 rounds of 20mm ammo per kill and NO daylight fighter was going to carry that ammo load and be able to stay on target long enough (multiple passes?) to fire it all anyway. These are averages from experten to green pilots. You can't build fighters set up for experten when you are running out of them.

 

[GrauGeist]

While titanium can be found in nature, the process to make it the metal we are familiar with is a lenght and costly process. It wasn't until the 1950's, that the Soviets were able to create a metallic compund that was useful for military applications.

The violence of the 30mm recoil (and to a lesser degree, the recoil of the 20mm) required the weight and structure of the Rhienmetall-Borsicht and Mauser designs. Keep in mind that the Germans were masters of engineering and ifnthey could have found a way to lighten the weapons, they would have.

As far as up-gunning the proposed Me262 with four MG151/20, sure, it's possible. You see the diagram with 6 cannon in the nose, so you know it can be done. But now, with 6 MG151/20, you have additional weight, reduced ammo capacity and the upper pair of MG151/20 have their barrels protruding. The additional weight and the exposed barrels are putting a performance penalty of your ship.

There is always the tendancy to cram "guns" in every nook and cranny possible, but in many cases, less is more. A pair of MG151/20 will do great damage to an opponent, four will do just that much more damage...even in a short burst at optimum range. With an adequate reserve of ammunition, you'll be able to have enough reserve to engage and destroy the enemy while your preciously short supply of fuel remains (80 minutes total - 30 minutes total time if engaged in combat) and perhaps enough to fend off "vultures" that were waiting at your base to shoot you down when your the most vulnerable.

 

[DerGiLLster]

I think you are working on a pipe dream. There is nothing the luftwaffe could have done short of coming up with a science fiction death ray and a plane that could be flown by not very bright and rather clumsy 14-15 year olds that would have stopped the American bombers in 1944. North American was building about 700 Mustangs a month. They were building about 500-600 P-47s a month and 3-400 P-38s, granted some were going to the Pacific but the chances of the Americans running out of fighters was pretty slim (throw in the British fighters and there was no chance).
People have been arguing for decades (and will argue for decades more) if the P-51 was the equal of certain models of the Fw 190 ( and few will push the 109K) but the main problem was that on average the American (and allied) pilots of 1944 were better than the German pilots of 1944. The Germans had their 'experten" but they were running out of them and the replacement pilots just didn't have enough training for more than a very few to survive their first combat missions. Sticking them in jets wasn't going to change things enough. The Germans weren't going to be able to play a war of attrition with the allied fighters and shoot down so many that the Americans would run out of fighters and send over bombers unescorted. They would simple wait a few weeks until another few hundred fighters were delivered.

The Germans only chance was to bypass the fighters and try to kill enough bombers (4 engines and 10 men are harder to replace than one engine and one man) so the Americans would stop/pause and rethink the bombing campaign.

The four 30mm cannon in the 262 was about as good as it was going to get for killing bombers. With average pilots getting about 2% hits of rounds fired the 262 carried enough ammo for 1-2 kills on 4 engine bombers. if you needed 15-20 20mm hits and only got 2% hits you need 720-1000 rounds of 20mm ammo per kill and NO daylight fighter was going to carry that ammo load and be able to stay on target long enough (multiple passes?) to fire it all anyway. These are averages from experten to green pilots. You can't build fighters set up for experten when you are running out of them.

Oh no Shortround6, I am not attempting to prove that this application in 1944 could have changed the tide of the air war. I understand that the air situation was completely hopeless in 1944. No, I don't want to push limits. I want to see what could have been possible. I understand that Germany's lack of better pilots was a factor in losing the air supremacy the Luftwaffe had in Europe. I am saying that if the Me 262 had been introduced around late 1942, there being experienced pilots in that time, with production of piston planes halting, shifting toward jet production, then a significant difference might have embroiled. Besides wasn't firing a cannon through a jet plane easier to hit the targets than that of a piston plane? Simply asking here, isn't it easier to hit a plane when the guns are in the nose and not in the wings? Wouldn't the removal of a flying prop in front of you give off a clearer view, and therefore improve accuracy?

I only ask for the most plausible possibilities, and also what do you think could have helped the Germans win the air war?

 

[GrauGeist]

The prop wasn't an aiming factor and German, Japanese and several other nations's aircraft had cowl mounted MG armament. The P-39 and Bf109 had a centline cannon that fired through the spinner, as did a few Soviet aircraft. The P-38 had nose mounted weapons, as did several "heavy fighters" and modified bombers (for ground attack).

It is true that a centerline mounted weapon can have better performance (accuracy) due to zero-convergance factors, but it's not a deciding factor.

 

[davebender]

Most of that weight is for the ground mount. Cannon itself was 57.5kg.


Hs.404 cannon wasn't terribly reliable. At least that's the official USAF opinion expressed in publication AFATL-TR-84-03. USA screw ups attempting to place the weapon into mass production may have swayed their opinion but lubricated ammunition as Hs.404 employed is generally considered a bad feature for any automatic weapon.


A few MG FF cannon had a power operated belt feed system. I suspect ROF was as good or better then standard magazine feed version. Why can't Germany apply same technology to the magazine fed Flak 38?


47,000 joules of muzzle energy.
Muzzle energy is the most important factor for armor penetration. For an aircraft cannon it matters only if it improves long range hit probability. Most damage is accomplished by shell HE payload ripping away pieces of the airframe.

 

[Glider]

I want to see what could have been possible. I understand that Germany's lack of better pilots was a factor in losing the air supremacy the Luftwaffe had in Europe. I am saying that if the Me 262 had been introduced around late 1942, there being experienced pilots in that time, with production of piston planes halting, shifting toward jet production, then a significant difference might have embroiled.

I only ask for the most plausible possibilities, and also what do you think could have helped the Germans win the air war?

To be honest even if the Luftwaffe had the 262 in 1942 the battle for the air would have been longer, the war itself drawn out, the number of lives lost increased and the end result would have been the same. In practical terms the RAF would have had Meteors and Vampires much earlier, plus the USA would have the P80. Having the 262 will do nothing to increase the threat to the UK which will still be secure in strategic terms and I have little doubt that Berlin would have been the first target for the nuclear bomb.