Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Apeking on December 15, 2006, 04:20:23 PM
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This is more of a real-life question than something to do with Aces High, and I imagine Tony Williams can answer it at the drop of a hat. I have been reading about the Mk 108 30mm cannon which is fitted in some of the late-war German planes. It's a fascinating thing and it has given me a great deal of pleasure in Aces High, but it has also caused me a great deal of pain, because it has led me astray, taunted me, placed me in danger and left me to die. As a work of art it looks wonderfully modern even today:
Mk 108 at Luft '46 (http://www.luft46.com/armament/mk108.html)
Really I have three questions. Firstly, why was the barrel so short? I assume there was a good practical reason - perhaps the shells could not withstand a higher muzzle velocity, or the gun could not function with a long barrel - but I have not yet heard it. From what I have read (on Tony Williams' own site!) it was a more compact revision of the earlier Mk 101, but it looks as if the designers threw out the baby with the bathwater by shortening the barrel so much.
Secondly, contemplate this fascinating cut-away of a 109 K4's weapon installation:
A faceless K4 (http://www.xs4all.nl/~rhorta/wk4.htm)
The Mk 108 spinner cannon looks comical; it barely enters the engine block. What bridged the gap between the cannon muzzle and the prop spinner? A plain metal tube (if only to prevent the muzzle blast from damaging the engine), or nothing at all, and if the former did it have an effect on the weapon's muzzle velocity?
And straying off topic, I have read that the Germans considered using the MK 108 as a ground-based anti-aircraft gun, because they had lots of them and they were easy to make. They seem very unsuited for this role, but on the other hand they are similar to modern-day 40mm grenade launchers. Did anyone think to put one in a light tank, or jeep? With the right shells it would be a potent anti-personnel, anti-light structures weapon.
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One correction to your post - the MK 108 was not derived from the MK 101, which used an entirely different mechanism. It would be more accurate to describe it as a scaled-up MG-FF.
The barrel was short partly because the cartridges contained very little propellant, which burned out after the projectile had only travelled a short distance up the barrel. The more propellant you have, the longer the barrel you need to get the most out of it. In the photo below you can see the huge different in size between the cartridges for the high-velocity MK 101/103 (30x184B) and the low-velocity MK 108 (30x90RB)
(http://www.quarry.nildram.co.uk/WW2aircart2.jpg)
Another reason for the barrel being as short as it was concerned the type of operating mechanism. The breech was not locked to the barrel at any time - when the gun fired, the breechblock was moving forwards, and the recoil first stopped it then pushed it back again. The shell had to be clear of the barrel before the cartridge case left the chamber, otherwise the case would burst and the plane's structure around the breech would be blasted with burning propellant. So the barrel had to be kept short to ensure that this did not happen. There is an obvious relationship here between rate of fire and barrel length: a heavier breechblock would move more slowly, giving more time for the shell to leave the barrel, so the barrel could be longer, but the Luftwaffe put rate of fire above muzzle velocity in their priority order for this gun.
As for your second question, there was a blast tube attached to the muzzle which ran between the engine blocks and up to the prop, otherwise the engine compartment would have been filled with gasses and soot from the muzzle blast. It didn't affect the velocity.
The Germans were in such desperate straits at the end of the war that they might well have considered using the MK 108 in the AA role, I don't know, but they would have made very bad AA guns - you need high velocity for that role. I agree that they could have made useful infantry weapons, but I don't know that that occured to anyone.
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
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A typically a well-written and informative answer. So the Mk 108 was basically a blowback gun along the lines of a Walther PPK or other compact pistols, but scaled up? And with a much bigger kaboom. It seems like one of those nearly-there-but-not-quite solutions, or a solution in search of a problem.
If the problem was a bursting cartridge case, could the designers have made the breech-face so that it wrapped around the end of the cartridge, along the lines of the telescoping bolts used in some modern submachineguns? I can't picture in my mind how the cartridges would have been ejected in this case.
I was struck by the 30mm cannon because my dad used to test cannon shells for the RAF, and brought home a dummy 30mm Aden round one day. I remember wondering what one of those things would do to you, if it hit you at supersonic speeds, even if it did not explode.
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Another interesting thing is that German aces universally disliked the three centimeter cannon, considering it unfit for destroying fighters. According to one of the aces, all it usually did was knock off skin. Add that to the terrible ballistics and relatively poor rate of fire, and it's no wonder they did not like it.
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Tony I have an odd question kind of related to this....
How much did necking down the brass effect the muzzle velocity? Just wondering what sort of gains and draw back the necking down has.
Apeking, when I was still in the Army as a Bradley gunner my bradley commander was in the first desert storm. Long story short the gunner in his bradley still had AP loaded when they came upon a group of iraqis who wanted to fight, well the gunner selected HE but you still need to cycle the ready round out of the gun or just fire it....well he decided to fire it. After the fight they found the guy he hit with the AP round...he was missing the left side of his chest from shoulder to hip. So just getting a chunk of metal going at 3600 ft/sec is going to be deadly. Plus that round after the sabot falls of is only about the diameter of a number 2 pencil and about as long as your pinky.
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How would one know whether a particular corpse was killed by high explosive or armor piercing bullets, if they both do such spectacular damage?
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Well with the optics in the bradley, its not too hard to put the pipper on 1 man at 1000m and hit him. Plus after you fire off the "ready" round you need to cycle the gun for the next type of round. So its not like firing off a machine gun. Take it or leave it I trust the guy but it's up to you. Try doing up the math on the kenetic energy of the 3.39g projectile going at around 4500 fps.
If I did it right it comes out to around 3000 Joules.
Also a .45 ACP has about 543 Joules.
Plus it wasn't a large scale engagement, more like a skirmish. Sounded like a few guys standing around with weapons in the path of some nasty hardware. ;)
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Originally posted by Benny Moore
Another interesting thing is that German aces universally disliked the three centimeter cannon, considering it unfit for destroying fighters. According to one of the aces, all it usually did was knock off skin. Add that to the terrible ballistics and relatively poor rate of fire, and it's no wonder they did not like it.
A few months ago i read a book by an east front 109 pilot who loved the 3cm gun
one hit would drop just about any plane, he said...
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MK108 is awesome in AH and apprently in real life. Here is what one round did in a post war british test.
(http://www.23ag.ru/assets/images/mk108blenheim.jpeg)
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MK 108 should be a perk weapon for ToD:aok
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No more than the 20mms on the spitfire should be. They have more of them, they are 90% more likely to hit the target, and more lethal in most cases when fired at the enemy. Both were the norm, why perk either?
EDIT: depending on when the tour starts, you may have to fly the G6 in the beginning, or the 190A5. You will probably advance up the ranks to the G14 (30mm) or the 190a8 (30mm) so at first it probably won't be available
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Originally posted by 1K3
MK 108 should be a perk weapon for ToD:aok
Do you know how few people can actually AIM it? I have practiced for AGES (I favour the 30mm over all others because of those few incidences where one shot ripped off important things like engines, wings or... tail sections ;) ) and I have a dreadful hit percentage!
Quick question: OUR G-14 has the Mk 108, correct? (From what ive seen the 101 seems more my type of gun)
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Sry for misunderstanding.
IF 1 round of MK 108 did this to a plane then it must be perked
(http://www.23ag.ru/assets/images/mk108blenheim.jpeg)
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Originally posted by 1K3
Sry for misunderstanding.
IF 1 round of MK 108 did this to a plane then it must be perked
I´m with Krusty this time: no need to perk. The lethality of a single round is being offset by the increased difficulty of actually achieving a hit.
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Originally posted by Apeking
If the problem was a bursting cartridge case, could the designers have made the breech-face so that it wrapped around the end of the cartridge, along the lines of the telescoping bolts used in some modern submachineguns? I can't picture in my mind how the cartridges would have been ejected in this case.
The MK 108 was an "Advanced Primer Ignition Blowback", which was a lot more sophisticated than a simple blowback pistol, because the breechblock was still moving forward at high speed when the cartridge fired. This meant that the initial recoil thrust was mostly used up in stopping the breechblock before it could be pushed back again - which meant that the breechblock could be a small fraction of the weight it would have to be in a simple blowback, where the breechblock is stationary at the moment of firing. A much lighter breechblock means a much higher rate of fire. In fact, a simple blowback wouldn't work at all in cannon calibres - the breechblock would have to be so heavy that if the gun were pointed upwards, it would slide back by itself since the spring wouldn't be strong enough to hold it.
In order to provide support for the cartridge case while it is being fired, API blowbacks have extended chambers, so unlike all other guns (where the chamber is a close fit around the cartridge) the cartridge is free to slide to and fro. Since the breechblock needs to be linked to the cartridge case by the extractor claw, that means the breechblock needs to be the same diameter as the cartridge case so it can follow the cartridge into the chamber. Normally this would be impossible because the extractor claw, fitting around the rim, would stick out from the case, but cartridge cases for API blowbacks are specially designed with rebated rims - the rims are smaller than the case - to allow this to happen. You can see the small rim in the pic of the 30x90RB above.
The API Blowback was first introduced in the German 20mm Becker cannon of WW1, then taken up by a couple of Swiss firms; first SEMAG, then Oerlikon, who made 20mm cannon in various versions. The most powerful Oerlikons were adopted by the British and US navies in WW2 as light AA guns, the less powerful ones adopted by the Japanese navy as aircraft guns (Type 99 cannon, as used in the Zero) and by the Luftwaffe, who called it the MG-FF. You can read a brief history of the Oerlikon family HERE (http://www.quarry.nildram.co.uk/apib.html)
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
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Originally posted by Reynolds
Quick question: OUR G-14 has the Mk 108, correct? (From what ive seen the 101 seems more my type of gun)
Correct. The MK 101 was far too big to fit into the Bf 109: so was the much more compact standard version of the MK 103 (see comparative pics of aircraft guns below). There was a modified version, the MK 103M, which could just squeeze into the engine mounting, but this seems to have been unsuccessful when tested, so never seems to have been used. Despite what some famous references say, the MK 103 was never carried by 109s in service - and neither was the MG 131.
(http://www.quarry.nildram.co.uk/AMgundrawJ.jpg)
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
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Originally posted by zorstorer
Tony I have an odd question kind of related to this....
How much did necking down the brass effect the muzzle velocity? Just wondering what sort of gains and draw back the necking down has.
The designers look at it this way: First they choose the calibre and weight of the projectile they want to fire. Then they decide what muzzle velocity they want to fire it at. That determines how much propellant they need to fit in the case (and also the barrel length). For a high-velocity gun they need lots of propellant, so a big cartridge case to hold it. They then have a choice - to make the cartridge case long and thin, or short and fat with a bottlenecked shape. You will usually find them adopting a short, fat case (to some degree, at least) because a shorter cartridge means that the gun action can cycle more quickly, which puts up the rate of fire.
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
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Originally posted by Tony Williams
Despite what some famous references say, the MK 103 was never carried by 109s in service - and neither was the MG 131.
Umm ... the MG 131 sure was carried by 109s.
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Originally posted by Viking
Umm ... the MG 131 sure was carried by 109s.
Sorry - a brain fart :rolleyes:
I meant to say that the MG 151 was never carried as a cowling gun...
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
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Originally posted by Tony Williams
The designers look at it this way: First they choose the calibre and weight of the projectile they want to fire. Then they decide what muzzle velocity they want to fire it at. That determines how much propellant they need to fit in the case (and also the barrel length). For a high-velocity gun they need lots of propellant, so a big cartridge case to hold it. They then have a choice - to make the cartridge case long and thin, or short and fat with a bottlenecked shape. You will usually find them adopting a short, fat case (to some degree, at least) because a shorter cartridge means that the gun action can cycle more quickly, which puts up the rate of fire.
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
Ahh ok so it's almost like they design a shell to do something then work backwards from there. Not a "We have this round now lets make a gun for it" sort of thing.
Thanks again Tony...no dark unknowns when Tony pops in :aok
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Originally posted by Debonair
A few months ago i read a book by an east front 109 pilot who loved the 3cm gun
one hit would drop just about any plane, he said...
Originally posted by GRUNHERZ
MK108 is awesome in AH and apprently in real life. Here is what one round did in a post war british test.
That's bombers. They were rather effective against bombers, although they still usually could take several hits. Fighters, however, had a vastly different structure and the round was not designed to deal with that.
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The Mk 108 wasn't designed 'for bombers'. Please quote the sources of all those pilots who 'disliked the MK 108'. From that same series of photographs Grünherz posted is a Spitfire that was completely destroyed by a single Mk 108 round. 1 hit on a fighter with a Mk 108 all but guaranteed an abschuß.
Minengeschoß - whether 2cm or 3cm worked the same way. If a fighter was resistant to 3cm then 2cm would have been even less effective. The LW were using MGFF/M during BoB.
LW estimated 5 hits with 2cm anywhere on a fighter was enough to bring it down. Minengeschoß were most effective against stress skinned aircraft - the blast would blow out panels weakening the aircraft structure. Now some planes like the Hurricane with its internally frame could have panels blown away and remain air worthy. Wood aircraft like the Mossie could absorb the blast as well.
In general the a single Mk 108 was enough to destroy most fighters. The MK 108 was specifically designed for use against bombers.
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"when I was still in the Army as a Bradley gunner my bradley commander was in the first desert storm. Long story short ... he was missing the left side of his chest from shoulder to hip" - that's one question I never expected to be answered. The internet is fantastic.
"aim" - I have had some success with the 108 against bombers; my standard tactic is to dive down from about 1.5k above and to the side, opening fire at dead point-blank range along the top of the target, diving just underneath in order to escape. The gunners usually can't aim very well in the vertical, perhaps because they are looking at the blank empty sky, and don't get a sense of relative motion. They can't switch views quickly enough to deal with a target that passes swiftly by at close range.
In theory a couple of hits should be enough to ruin a bomber, but in combat I find it impractical to fire, check the fall of shot, and fire again, so I waste lots of these precious, precious explosive truffles ensuring overkill.
Sometimes I feel that the score pipper should say "X landed N kills with 4x20mm" or "Y landed N kills with 8x12.7mm" rather than listing the airframe.
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Originally posted by GRUNHERZ
MK108 is awesome in AH and apprently in real life. Here is what one round did in a post war british test.
(http://www.23ag.ru/assets/images/mk108blenheim.jpeg)
The round was suspended inside the fuselage not fired at the fuselage.
There is a simular photo of Spit used during the testing.
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Originally posted by Benny Moore
That's bombers. They were rather effective against bombers, although they still usually could take several hits. Fighters, however, had a vastly different structure and the round was not designed to deal with that.
the guy from the east front was mainly working against Jaks, Las, Il-2s, Pe-2s & P-39, standard VVS stuff....
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Originally posted by Apeking
[B"aim" - I have had some success with the 108 against bombers; my standard tactic is to dive down from about 1.5k above and to the side, opening fire at dead point-blank range along the top of the target, diving just underneath in order to escape. The gunners usually can't aim very well in the vertical, perhaps because they are looking at the blank empty sky, and don't get a sense of relative motion. They can't switch views quickly enough to deal with a target that passes swiftly by at close range.
In theory a couple of hits should be enough to ruin a bomber, but in combat I find it impractical to fire, check the fall of shot, and fire again, so I waste lots of these precious, precious explosive truffles ensuring overkill.
Sometimes I feel that the score pipper should say "X landed N kills with 4x20mm" or "Y landed N kills with 8x12.7mm" rather than listing the airframe. [/B]
As a bomber guy, yeah, thats a good tactic. I get disoriented when that happens. Just make a point of rolling over when you drop under and coming up the same way you came in. I always kill people in that maneuver by waiting in the ball gun and blasting their canopy from above. In fighter, I find my best 30mm kills are from above and behind. I need to come at speed, but Im NOT normally using the R6, so I am working with just 65 rounds. I aim for the No. 2 engine and fire about 5 or 6 into that general area. IF they dont kill you, (Which is why speed is of the essence) they will die. I favor my aim over my chances of survival. That tends to pay off ;)
As far as aiming, do you use the german Revil sight? The second pip down is the general area I find at 200-400 meters. (Or yards, whatever we measure in...) My fewest shots to kill a bomber were 3, right into the no. 4 engine.
I dont like that idea, unless it lists the guns AND aircraft, because the airframe is as much of an impact on kills as the gun. ALthough it IS interesting. I always ask other 109 pilots if they fly with the /R6 and whether they use 20 or 30mm. I find the BEST kills are gained from the 20mm, but the most spectacular and most enjoyable ar with the 30mm. The best enemy 109s I have experienced as well were 30mm.
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Ive used the 30mm alot since i re-joined AH and i have come to love it and be fairly accurate with it. Im guessing one in five of my 30mm rounds land on buffs but against fighters its abit less.
It is an awesome weapon and has made me a better gunner than i ever was in Ah1 when i was "spoiled" with the jug guns... and i still fly with a mouse.
Stupid me have told the missus that i want a joystick for xmas (her eyes lit up for a few seconds until she realised what i had in mind) so i cant really buy one before that.
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Originally posted by Nilsen
Stupid me have told the missus that i want a joystick for xmas (her eyes lit up for a few seconds until she realised what i had in mind) so i cant really buy one before that.
What other kind of "joystick" would YOU want for christmas that SHE would enjoy so much... Unless surgery was involved...
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Fighters, however, had a vastly different structure and the round was not designed to deal with that.
Please clarify.
How would a fighter structure differ froma bomber structure?
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"As far as aiming, do you use the German Revi sight?"
I don't like using gunsights at all. They are prescriptive, and I dislike that kind of old-fashioned linear thinking. The more I play Aces High, the less I rely on my visual sense. Nowadays I find myself hunting and shooting with my ears and tongue more than I do with my eyes. I use my eyes less and less because they constrain my ability to feel.
For several weeks now I have been developing a new form of aerial combat. It is the skill of shooting truthfully. I do not look at the gunsight, or at anything except for the RPM indicator. The RPM indicator is steady, and I admire that quality. It is a circle, like a woman. All of the universe can fit inside the RPM indicator of a Bf109K4.
Whilst you people fixate on your aerial manoeuvres and tactics, I have come to realise that the only way to win consistently is to smother the enemy with the power of my mind. And with my desire.
The cloud is the most successful aircraft in the game. The cloud guiles its enemies. It flows around and smothers them. They do not realise that they have lost. But they *have* lost. And that is what I hope to do with my new thinking, in the cockpit of my fighter plane.
Mind plus desire into action. That mantra is my gunsight.
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Originally posted by Kweassa
Please clarify.
How would a fighter structure differ froma bomber structure?
I'll humor you. Bombers have great, open spaces. Fighters have small, compact spaces filled with stuff.
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Originally posted by Benny Moore
I'll humor you. Bombers have great, open spaces. Fighters have small, compact spaces filled with stuff.
Hmmm... explosions in great open spaces usually do less damage then in small spaces cramped with equipment ;)
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Originally posted by Apeking
"As far as aiming, do you use the German Revi sight?"
I don't like using gunsights at all. They are prescriptive, and I dislike that kind of old-fashioned linear thinking. The more I play Aces High, the less I rely on my visual sense. Nowadays I find myself hunting and shooting with my ears and tongue more than I do with my eyes. I use my eyes less and less because they constrain my ability to feel.
For several weeks now I have been developing a new form of aerial combat. It is the skill of shooting truthfully. I do not look at the gunsight, or at anything except for the RPM indicator. The RPM indicator is steady, and I admire that quality. It is a circle, like a woman. All of the universe can fit inside the RPM indicator of a Bf109K4.
Whilst you people fixate on your aerial manoeuvres and tactics, I have come to realise that the only way to win consistently is to smother the enemy with the power of my mind. And with my desire.
The cloud is the most successful aircraft in the game. The cloud guiles its enemies. It flows around and smothers them. They do not realise that they have lost. But they *have* lost. And that is what I hope to do with my new thinking, in the cockpit of my fighter plane.
Mind plus desire into action. That mantra is my gunsight.
:huh
Anyone else follow?
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Not so much.... but it sounds like fun.
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Originally posted by Lusche
Hmmm... explosions in great open spaces usually do less damage then in small spaces cramped with equipment
Ah, but the shells in question were specifically designed for maximum damage in open spaces. I'm not sure exactly how it works, but apparently the shell explodes after impact with one side of the fuselage. The shrapnel expands as it travels through the open space and then tears a wide area out of the opposite side of the fuselage. For obvious reasons, this doesn't work well when it hits wings. And the clutter inside of the fuselages of fighters tends to absorb shrapnel, although it's certainly not good for that clutter (radio, oxygen, fuel, control cables). But the point is that it's not going to magically disintegrate a fighter as people are led to believe. It's like the difference between shooting a hollowpoint at an empty can and shooting one at a can of sand.
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Didn't work that way.
The round had a spinning detonator inside it. The rifling bore of the gun itself spun the round, and the core would rotate with it. When the round decelerated suddenly (upon impact) the core flung forward and 2 contacts (of whatever) met and detonated the explosives.
This is a round with a slow enough muzzle velocity that it's not going to overpenetrate ANYthing.
So barring that, it's a hand grenade. Nothing more. Put a grenade in an open space, and do LESS damage. Put a grenade in a small space, and blow the living daylights out of it. The same explosion in a smaller, confined, space, will do more damage. That's just physics. Not to mention fighters were crammed in almost every inch of their wings, fuselage, tail, nose, with vital components. Bombers had a lot more space where there were no vital components (unless you count gunners?). 30mm will do more damage to a fighter than a bomber because of these reasons.
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That's an assumption that both air forces and loads of German aces disagree with.
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I don't think so. Even the Germans admitted it took 3-5 30mm rounds to take down heavy bombers, but that any single hit would doom a fighter.
It was MADE for bombers. It was USED against both bombers and fighters. They developed the 30mm to stop bombers, but that doesn't mean it was ANY less powerful against fighters. Put a cherry bomb on your palm. Set it off. You get a slightly scorched palm. Put one on your palm and make a fist around it and you've just blown your fingers off.
Put a 30mm in the open fuselage of a bomber, and it'll do a helluva lot of damage. Put one inside the structurally confined, enclosed wing/tail/fuselage of a fighter, and you've just killed a fighter.
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Well, all I can offer at the moment is a statement by a Focke-Wulf 190 pilot that all they did to fighters was blow off skin. I wish I could source it but I can't.
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Sooo lemme get this straight.
An exploding round does less damage on a smaller target .
And it does more damage on a larger target.
Ok got it.
:rolleyes:
Bronk
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Just let Tony read this and come in with the "Right Hand of Tony" (tm) and set this straight ;)
I am sure he has it worked up on his site....or just plain old knows ;)
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Originally posted by Bronk
Sooo lemme get this straight.
An exploding round does less damage on a smaller target .
And it does more damage on a larger target.
Ok got it.
Ever shot a gun? Smaller often means denser. I've shot hollow objects with hollowpoints, and I've also shot smaller solid objects with the same. Hollow objects get torn apart, solid objects just get small holes.
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An extract from Flying Guns – World War 2: Development of Aircraft Guns, Ammunition and Installations 1933-45 (http://users.skynet.be/Emmanuel.Gustin/volume1/index.html):
"The 30 mm HEI M-Geschoss, fired from an MK 108, was also tested. Unsurprisingly, ten rounds fired at a Spitfire fuselage resulted in a score of three immediately lethal, seven probably lethal. Eleven rounds fired at a Blenheim achieved the same results, plus one doubtful. It was noted that the ammunition did not have much effect on heavy bomber fuselages (presumably because of the large volume for the explosion to dissipate into), but inflicted serious aerodynamic damage to the wings by blowing off the surfaces, and that the incendiary content was very effective in starting fires. German tests reflected these results, and also revealed significant differences in the effectiveness of the mine shells depending on the construction of the aircraft. Stressed-skin alloy monococque structures were most vulnerable to being blown apart. Steel structures clad with thin aluminium were less affected as the cladding quickly split, releasing the pressure before it had much time to damage the structure, and fabric-covered structures were damaged least of all. It was not only the blast which inflicted damage; after the war, the Americans test-fired an MK 108 HEI shell into the tail of a B-24 at a typical angle, characteristic of a tail interception by an Me 262. The "spray" pattern of very high velocity, very small fragments cut most if not all of the control cables and many of the longerons. It was assessed that the tail would have separated if the plane had been in flight; a performance which made a great impression on the observers."
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
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Originally posted by Benny Moore
Ever shot a gun? Smaller often means denser. I've shot hollow objects with hollowpoints, and I've also shot smaller solid objects with the same. Hollow objects get torn apart, solid objects just get small holes.
Hu ?
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Okkkkay..
So we've got a professional historian and WW2 ammunitions expert saying;
It was noted that the ammunition did not have much effect on heavy bomber fuselages (presumably because of the large volume for the explosion to dissipate into), but inflicted serious aerodynamic damage to the wings by blowing off the surfaces, and that the incendiary content was very effective in starting fires.
...and a non-significant person saying..
Ah, but the shells in question were specifically designed for maximum damage in open spaces. I'm not sure exactly how it works, but apparently the shell explodes after impact with one side of the fuselage. The shrapnel expands as it travels through the open space and then tears a wide area out of the opposite side of the fuselage. For obvious reasons, this doesn't work well when it hits wings.
I go with the professional historian.
Sorry, Moore. You're just not a reliable source.
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Originally posted by Benny Moore
Ever shot a gun? Smaller often means denser. I've shot hollow objects with hollowpoints, and I've also shot smaller solid objects with the same. Hollow objects get torn apart, solid objects just get small holes.
If your hollowpoint was filled with explosives and detonated on impact I'd say you could try this comparison, but having shot a quite a few rounds off myself I can say definitely that bullets and cannon rounds are different animals entirely.
A hollow point striking a hollow target and fragmenting / ripping it apart is still simple kinetic energy, even if split into multiple fragments which travel completely through the target. A hollow point hitting a solid target which absorbs the fragments after the initial penetration is still suffering from the kinetic energy, and the fact that the fragments don't come out the other side doesn't mean that any less damage was caused.
A solid target (like a man), hit by a 9mm gets a 9mm hole drilled through him. Hit by a 9mm hollow point which fragments, that solid target gets the fragments ripping through which tends to cause much actual damage. Same 9mm hole, different results.
A cannon round is completely different - besides the initial kinetic energy, you get the high explosive detonation after impact. This gives you some lovely fragmentation, and more importantly a nice explosion with all the added energy of the blast effects / overpressure. The picture up the thread of the 30mm exploded while suspended in the fuselage gives you an idea of how much energy just the EXPLOSION releases.
Couple that explosion with the actual kinetic energy of the round, plus realize that the target and the round are both MOVING when the detonation occurs, and you get an even bigger mess. I don't know that HTCs damage model can be accurate on the directional effects, but the overall effect of a 30mm hit on aircraft seems OK to me when I'm in my 109K4.
Can a fighter survive a Mk-108 30mm hit - maybe, they aren't designed to penetrate armor, so if it hit an armor plate maybe you could take one if the blast didn't blow off anything vital. Set one off in the wing of a P51 near that wing tank, and I'd say your toast. It all depends on the situation.
EagleDNY
$.02
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Watch this:
http://www.youtube.com/watch?v=Oc9E8_ZuESQ
Then there was a video where some guys fired a 30cal, 50 cal and 20mm AP and HE on a wing dummy made of sheet alu, but I cannot find it to save my life.
Anyone has a link?
Pretty impressive when you compare 20mm HE with 50cal ball.
I have the said vid on my HD, but no upload space. Any directions to do this?
Matt
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Originally posted by Benny Moore
Ever shot a gun? Smaller often means denser. I've shot hollow objects with hollowpoints, and I've also shot smaller solid objects with the same. Hollow objects get torn apart, solid objects just get small holes.
Ever blow stuff up?
Try putting an M-80 in a ... mailbox. (I do not endorse doing it but have seen first hand what it does.)
Blows the hinged lid off. Often times blossoming the end or even blowing it off the post.
Now take that same M-80 and drop it in a 33 gal trash can .
While it will blow the lid off it will hardly distort the shape of the can.
Bronk
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Originally posted by EagleDNY
Can a fighter survive a Mk-108 30mm hit - maybe, they aren't designed to penetrate armor, so if it hit an armor plate maybe you could take one if the blast didn't blow off anything vital. Set one off in the wing of a P51 near that wing tank, and I'd say your toast. It all depends on the situation.
EagleDNY
$.02
In ALL of the time I have fired 30mm I have never seen ANY plane smaller than a B-24 survive the impact of even ONE 30mm. From all I have seen, one shot + one hit = one kill. Even P-47s fall apart. This is a BIG round, with a BIG boom. Its kinda like smashing a hole open with a baseball bat and tossing a grenade inside. It goes BOOM in a big way. I dont know who this Tony Williams guy is, I have never heard of him, but I have yet to see a single word typed by him that didnt sound like it came from the maker of the shell himself. He knows his guns. There is virtually NO way a fighter takes less damage from a 30mm. The ONLY situation in which I can fathom a fighter taking less damage is on a fabric plane where the shell doesnt decelerate from the impact enough to detonate and goes out the other end. Anything with stressed metal, aluminum, and probably wood is TOAST. Even Mosquitoes fall apart when I shoot them. The 30mm is teh ub3r 1337 when it comes to guns! :D
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anyone have a copy of the photo of a P-51 that took an Mk108 hit in the vertical stabiliser?
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"anyone have a copy of the photo of a P-51 that took an Mk108 hit in the vertical stabiliser?"
Probably not. I bet there is not much left to take pictures of. :D
-C+
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The mk 108 is not that heavy compared to the mk 103, coming in at less than half the wieght.One round took the tail clean off a f4u1a last night.:aok
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Originally posted by Reynolds
In ALL of the time I have fired 30mm I have never seen ANY plane smaller than a B-24 survive the impact of even ONE 30mm. From all I have seen, one shot + one hit = one kill. Even P-47s fall apart. This is a BIG round, with a BIG boom. Its kinda like smashing a hole open with a baseball bat and tossing a grenade inside. It goes BOOM in a big way. I dont know who this Tony Williams guy is, I have never heard of him, but I have yet to see a single word typed by him that didnt sound like it came from the maker of the shell himself. He knows his guns. There is virtually NO way a fighter takes less damage from a 30mm. The ONLY situation in which I can fathom a fighter taking less damage is on a fabric plane where the shell doesnt decelerate from the impact enough to detonate and goes out the other end. Anything with stressed metal, aluminum, and probably wood is TOAST. Even Mosquitoes fall apart when I shoot them. The 30mm is teh ub3r 1337 when it comes to guns! :D
I've flown 109K4s, come in on a bomber seen multiple hits and the bomber (B17) survive the pass. Was that MG fire and not multiple cannon hits? Who knows, but the bomber kept on going.
Fighters that get hit with a 30mm round in AH are basically toast, and rightly so. I've gotten single hits on P47s and it brought them down, and the P47 is probably the toughest fighter in the game. I've also gotten hits on fighters that I would've swore was a cannon hit and they survived.
IRL I do remember reading an account of a Jug pilot who took a cannon shell to the engine which actually blew cylinders off, yet he was able to get his plane home. It is pretty amazing sometimes to see pictures of planes that took severe hits yet still made it back to base - wingtips, engines, stabilizers shot completely off and still flying.
I agree that a 30mm hit is devastating, but I do hesitate to say that it is 100% instantly fatal to a fighter. That said, I sure don't want to be on the receiving end ;)
EagleDNY
$.02
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I've had two surprising experiences against Ki61's, one with a LW 30mm and the other with a VVS 37mm where they took the hit as they crossed vertically across my sights, so nigh on perpendicular, in roughly the same place - just inboard of the aileron, and they've carried on flying with no visible damage.
I've also blown my own arse off, given myself pilot wounds, oil and radiator leaks, broken my guns, by shooting too close with said weapons.
edit. Eagle I think I've read something similar about a P47 losing huge chunks of engine yet still the pilot had the confidence to do some light strafing of railroads and ships, on his way back to base. Pretty amazing.
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"I have yet to see a single word typed by him that didnt sound like it came from the maker of the shell himself"
Emmanuel Gustin, the co-writer of the quoted book, gives a thorough overview of historical aircraft armament here. (http://users.skynet.be/Emmanuel.Gustin/fgun/fgun-in.html) I am sure that this has been posted many times before. But not by me. Him, Tony Williams, Greg Goebel, and Mark Prindle are the only people I trust on the internet. And also the Russian chap, you know. Maxim Popenker. And also Greg Starostin. NB My interests run to more than just guns, planes, and the Ramones.
There are some charts of weapon performance on Emmanuel's site. They strongly suggest that the ultimate aircraft gun is the Russian GSh-6-23, a six-barrel rotary cannon fitted in the Mig 31. It weighs about the same as me, and fires at 8-10,000rpm. A single GSh-6-23 has over twice the weight of fire as four 30mm Mk108s, and is one of the hardest cannons to type. I have no idea why the Russians put a cannon in the Mig 31. I can understand why this particular cannon might have been fitted into a Mig 31. But for what purpose?
There is also a chronological list of fighter armaments, which reveals that the Me262's 4x30mm weight of fire - which is of course just one attribute - was roughly equivalent to twenty-two yankee 12.7mms. I did not know that the Bf109K6 existed and could be fitted with 3x30mm. I bet it's on someone's wishlist.
I find it hard to write about Emmanuel Gustin's website without thinking of a naked Sylvia Kristel swimming in a pool. But is that such a bad thing?
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The GSh-6-23 was fitted to the MiG-31 primarily to deal with easy or low-value targets not worth one of its big AAMs, such as cruise missiles (and nowadays UAVs, no doubt).
However, the gun (which is also fitted to the Su-24) has run into problems with premature shell detonations causing damage to the aircraft, so these days they don't use them (the planes keep the gun, but it's never loaded).
As a matter of interest, my specialities are ammunition and guns, Emmanual's aircraft and gun installations. I helped him with his website initially, then we decided to co-operate on the Flying Guns series. You will find various other articles on aircraft guns (ancient and modern) on my website.
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
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Originally posted by Keiler
snip
Then there was a video where some guys fired a 30cal, 50 cal and 20mm AP and HE on a wing dummy made of sheet alu, but I cannot find it to save my life.
Anyone has a link?
Pretty impressive when you compare 20mm HE with 50cal ball.
I have the said vid on my HD, but no upload space. Any directions to do this?
Matt
Found it:
http://video.google.de/videoplay?docid=-9101895862044064019&q=20mm
Testfire with different calibres on a wingdummy.
Enjoy!
Matt