Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: bustr on July 01, 2010, 03:21:10 PM
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I've been looking at this test of a 30mm 108 video for awhile. Is this a real video from WW2 or doctoed by the web site at the bottom of the running video?
http://www.youtube.com/watch?v=ZoLLDi-M3fk&NR=1
History.virtualfighters.cz
http://history.virtualfighters.cz/Czech-RAF-guncamera-films.html
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I don't think it is fake, I've seen similiar footage of tests like that.
Shame the Czech site isn't translated.
ack-ack
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So the close up picture of the spit wing single 30mm impact damage from 100yd, in this games terms, is that sevier enough damage to disable the aircraft? That was only an impact with the upper trailing edge of a spit wing. How does our current damage model register the same round hitting the same spot?
The 30mm round had 85 grams of explosive while the standard stick granade had 115 grams. Watching the explosion in the film one has to consider how active and visibley destructive the explosion presents itself. There is a discrepency in the film. The 30mm tracer round did not explode on contact but had a fuse that exploded in contact with liquid.
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Text by. www.luft46.com
There were two main types of ammunition for the MK 108 to use, a 30 mm high-explosive self-destroying tracer ("M-Shell" or "Mine-Shell") and a 30 mm incendiary shell. The first type was designed to cause a maximum blast effect by combining a very thin shell casing with the maximum load of explosive. Tests carried out at Rechlin (where most of the Luftwaffe aircraft and weapons tests were done) showed that with a "M-Shell" with 85 grains of explosive, five hits could destroy a B-17 or B-24 bomber. The second type of shell, the incendiary, was meant to be targeted at the fuel tanks of the enemy plane. Since some penetrating force was still needed to overcome the armor or airframe of the target, and not have the shell break up or explode upon contact, a hydrodynamic fuse was fitted so that the shell only exploded once it came into contact with liquid.
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Tracer and incendiary are two different things. The video looks real enough and the round is probably a 3 cm Minengeschoss Leuchtspur mit Zerleger (day tracer) or 3 cm Minengeschoss Glimmspur mit Zerleger (night tracer).
http://www.xs4all.nl/~robdebie/me163/weapons15.htm#Type N
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At 0:56 into the video one can see a hole (above the 'irt' in virtual fighter). Is this caused by the 30mm round?
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Ack Ack, Google Translate doesn't do too bad of a job if you want to explore more:
http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=1&eotf=1&u=http%3A%2F%2Fhistory.virtualfighters.cz%2FCzech-RAF-guncamera-films.html&sl=auto&tl=en (http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=1&eotf=1&u=http%3A%2F%2Fhistory.virtualfighters.cz%2FCzech-RAF-guncamera-films.html&sl=auto&tl=en)
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My aplollogies you are right about the two rounds I booffhed up.
Anyone have an answer about the damage modle in relationship to the explosive damge and location we see in the film?
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So the close up picture of the spit wing single 30mm impact damage from 100yd, in this games terms, is that sevier enough damage to disable the aircraft?
Well, at the end of the film, it lists the results of the damage, showing that the rear spar, several ribs, and a large chunk of the wing surface area is destroyed. It then characterizes the damage as "probably lethal" from an aerodynamic and structural perspective and "lethal" from a loss of control perspective. So, given that the impact of a tater in game blows your wing off, I'd say that's a fairly good representation of what happens in real life. Are there hypotheticals in real life that might allow the pilot to fly after similar damage? Perhaps, but for most cases, the plane would be doomed. And, it seems to me that HTC has to have some sort of standard that doesn't allow for some of those hypothetical situations. So, you get in the wing with a tater--the wing comes off. I think that's fair, especially considering the alternative would be to randomize how damage is applied to the aircraft, and none of us really want that.
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Stoney,
Thank you.
If this seemed like a fishing expedition, I felt that way in it's implimentation But. The subject around the 30mm and its damage has been sensative in this game. I had never seen this film before so wanted to pass it by for the smell test then offer it up for question and comparison to the current damage model. I'm not a historical film analyst or subject matter expert. I was afraid it was a very good bit and splicing out of context from other films and photoshoping. The last written bit about the damage didn't read like similare things I had seen in other films from the era. More the flavor of CZ web pages I have translated with Google.
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Stoney,
Thank you.
If this seemed like a fishing expedition, I felt that way in it's implimentation But. The subject around the 30mm and its damage has been sensative in this game. I had never seen this film before so wanted to pass it by for the smell test then offer it up for question and comparison to the current damage model. I'm not a historical film analyst or subject matter expert. I was afraid it was a very good bit and splicing out of context from other films and photoshoping. The last written bit about the damage didn't read like similare things I had seen in other films from the era. More the flavor of CZ web pages I have translated with Google.
Well, personally, I've been skeptical about the relative power of cannons versus "slug" weapons in this game since I started playing. Unfortunately, I don't know enough about ballistics and the weapons, so, after making my initial ignorance public, as documented in a couple threads from 2007, I pushed the "I believe" button.
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I suppose the casing around the 85grams of explosive in 30mm is not much thicker than the canister around the 115grams of explosive of the german stick granade at the time. I would suspect since the early war version of the stick granade relyed on concusion opposed to sharpnel, then halving the effect on the surface of an aircraft structure is expected. Too bad we don't have links to accepted ordinance testing reports from WW2 along with films of testing by ordinance groups to review. This spitfire wing test is the first film of real time testing of the 30mm I've ever seen.
In the post I started about Tony Martin there is a link to the discussion he took part in. In that thread is a photo of the damage a 30mm did to the tail gun of a B17. The gun position was totaly destroyed by a round. The starbord elevator is damaged from a second round. Intersting is that the elevator span on the B17 is about the spitfires wing span but not as damaged as the spitfires wing. But then the B17 was built to with stand damage because it was expected to be repetedly attacked during business hours. You can also see blast preassure damage forward into the back of the starbord wing that has caused upward deformation of the wing structure and skin on one of the strongest wing structures in WW2. 85 grams of HE must put out some blast preassure wave.
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Just for comparison see what a Hisso HE does when it gets to build up some pressure:
http://www.youtube.com/watch?v=-p8h43TRXwk
-C+
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Legit film. I believe it was postwar testing. It's a Spitfire IIb
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The page basically says,
Never seen before czech gun footage, capturing the actions and shot down of the following pilots, Otty Smika, Miroslava Liškutína, Stanislava Hlučky, Františka Louckého, Otmara Kučery in September 1943, before you could only read about it, but now you can see it with your own eyes but the film quality is really bad. If anyone has any more videos or information he welcomes them. he might have some more videos.
Thats basically what it says, not word for word.
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I suppose the casing around the 85grams of explosive in 30mm is not much thicker than the canister around the 115grams of explosive of the german stick granade at the time. I would suspect since the early war version of the stick granade relyed on concusion opposed to sharpnel, then halving the effect on the surface of an aircraft structure is expected. Too bad we don't have links to accepted ordinance testing reports from WW2 along with films of testing by ordinance groups to review. This spitfire wing test is the first film of real time testing of the 30mm I've ever seen.
Actually the 30mm Mk108 rounds had a thicker projectile shell than the hand grenades. The hand grenade was basically a small steel can filled with explosive, to get more shrapnel effect there was an optional thin steel sleeve that could be placed over the head of the grenade.
(http://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Steilhandgranate_Schnittmodell_db.jpg/220px-Steilhandgranate_Schnittmodell_db.jpg)
(http://www.xs4all.nl/~robdebie/me163/images/large/weapon27.jpg)
You can see the difference in the amount of shrapnel material between the two.
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Looks like the thicker base on the 30mm creates a shaped charge type of controlled explosion. The picture of the B17 I referenced shows a upward pushed half round buckling of the trailing edge assembly and skin just behind the inboard starboard engine. Sort of looks like a directional blast wave several feet in diameter. In the film the explosion of the 30mm has that same shaped charge directional explosion pattern. Wonder how our spits in the game would fly with that much skin ripped up and off the upper wing surface along with the internal damage?
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Looks like the thicker base on the 30mm creates a shaped charge type of controlled explosion. The picture of the B17 I referenced shows a upward pushed half round buckling of the trailing edge assembly and skin just behind the inboard starboard engine. Sort of looks like a directional blast wave several feet in diameter. In the film the explosion of the 30mm has that same shaped charge directional explosion pattern. Wonder how our spits in the game would fly with that much skin ripped up and off the upper wing surface along with the internal damage?
Can't be tested. You hit a Spit in the wing with a 30mm and the wing comes off. Spits have the most fragile wings of any aircraft, so far as I can tell, in AH.
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Because gyrene was kind enough to post the pics we can see a bit of the purpose driven designs between the two German ordinance. The stick grenade explodes with a blast wave to impact a general sphere and distance of influence. The 20mm-30mm round and probably the 37mm-40mm rounds are in effect quasi shaped charges that may or may not have a hardened tip or core for penetration. Let me reference back to the damage picture of the B17 and ask a question about the games damage model.
Historic photographs show us P47's and bombers returning home with direct hits from flack and 20-30mm cannon damage. Flack damage looks like an omnidirectional blast with shrapnel smashing into the airframe. Cannon damage all looks like a shaped charge punching through the airframe in an expected cone of destruction. With the increased granularity of our damage model we should be seeing more aircraft fly away with cannon hits than with the older damage models? Admittedly not flying very well but, not turning into an exploded pile of pieces or half the airframe dropping off like they used to every time a cannon round hit them.
I'm considering that the B17 airframe having buckled and the rear gun position shattered, the explosion still was absorbed by the aircraft and nothing suddenly fell apart killing the plane. Then the demonstration of the 30mm against the spit wing. I'm assuming the orientation of the spit to the cannon was to duplicated a 6 shot which would be common. Even knowing the spitfires wing is the weakest, the explosion still didn't saw it off. Yes in flight the wing probably would have snapped off from stress. If the wing had been oriented so the round hit it 90deg to its upper surface, would we then have been looking at an explosion and a 1-2ft dia hole? Or in the fuselage rear of the pilot? Just a hole, or would the rear half of the fuselage tumble away? Even the trailing edge of the rudder? The whole vertical stab or just the moveable plane snaped off?
I'm reminded of M80's and paper bags. If you set one off in a closed paper bag, the bag will quickly rupture, yes absorbe some of the energy but the explosive gases will take the path of least resistance out the rupture. Riveted and welded aluminum structurs would perform similarly especialy considering how thin the aluminum skins on WW2 aircraft really are. If you place a stick of dynamite in the same bag yes, the bag will go poof with the explosion. Possibly like a direct hit from a Flack-88. Or then again you link up four M80's in that bag.
This direction of reasoning would venture quantity and shot placement rather than single cannon golden BB's with the new damage model. I can see a few more rounds being needed lately to bring down the red guys.
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Historic photographs show us P47's and bombers returning home with direct hits from flack and 20-30mm cannon damage. Flack damage looks like an omnidirectional blast with shrapnel smashing into the airframe. Cannon damage all looks like a shaped charge punching through the airframe in an expected cone of destruction.
Just a tidbit:
Until 1945, German heavy flack rounds did exclusively use timed fuses, they didn't explode on impact. That means almost all hits where the result of shells exploding externally, at some distance from the plane, which leads to a very different effect than being hit by a cannon shell that is impact fused.
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I'm taking a tad bit of license with imagery. The cannon rounds are effectivly cylindrical shaped charges. You can tell by looking at the directional damage pattern. Flack had concussion and shrapnel. I suspect 2-3 times the grams of explosive as the stick grenade with a thick enough casing to protect the fuse and survive the cannon barrel. The shrapnel from the AA fused round would be the primary killer kind of like modern AtoA missles packed with ball bearings or frangable wire. Very close by detonation or direct hits seemed less common than sharpnel damage.
You might equate the directional blast of the 30mm to fireing a 12g point blank into the airframe. Today there are exotic 12g rounds that act like a WW2 30mm. If you did not place the 12g point blank to the pilot compartment, engine or fuel tank the blast is mostly a blast against a hollow alluminum structure. So my statement related to our damage modle:
This direction of reasoning would venture quantity and shot placement rather than single cannon golden BB's with the new damage model. I can see a few more rounds being needed lately to bring down the red guys.
Recently in a K4 I attacked a box of Lancasters and fired 5 golden BB's diving in from the front quarter. One 30mm each must have hit pilots compartments because two of the Lancs performed the death spiral together with the third's rear gunner killing my engine while I passed behind it. A few sorties later I killed all three B26 in a box with a K4. It took 20-30mm per B26 to take them down. I'm suggesting the latter is more the nature of how the 30mm will function with the current damage model. The former was Luck.
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No "imagery licence" required; the design of the Minengeschoss rounds (both 20mm and 30mm variants) was not meant to damage the internal structure of the aircraft, but to blow off large areas of skin. In most WWII aircraft the skin was an integral structural component (so-called stressed skin) and if enough of it was removed the underlying structure would catastrophically fail. If it was flying that spit, unless extremely lucky, would lose that wing fractions of a second after being hit.
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Well it could be fake it look's more of an explosive impact rather than armour piercing and tracer fire.
But hey it could be a film from German propaganda. Hitler and Himmler where big on that stuff. :-)
EH who know's :headscratch: :headscratch: :headscratch:
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I've been looking for a pic of a Bristol Blenheim that they exploded a 30mm round inside the rear fuselage.
IIRC it's been posted on this BBS at 1 time,anyways the Blenheim had the round electrically detonated while suspended in the middle of the rear section of the fuselage several feet infront of the tail section. The explosion looks to have ruptured the airframe in all directions for about 3 or 4 feet.
I wish I could find that pic but havent been able to.
:salute
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I wish I could find that pic but havent been able to.
(http://www.airwar.ru/image/i/weapon/mk108blenheim.jpg)
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Thx Lusche!
As usual your contributions are to be commended. :aok
Now to be honest this wasnt fired persay but it shows the devistation that the 30mm round can do.
:salute
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Would it have mattered to the volume of expanding gasses from the explosion if they had punched a hole in the skin next to the round before it was detonated?
The photos of U.S. aircraft I have seen seem to indicate the U.S. design requirements were the flying tank school of thought while the 30mm in the photos exploded very near its entry hole. That Blenie looks like it was designed with low weight and rifle caliber rounds from the enemy during it's design period in the 30's. If HiTech puts the Blenie in this game I ain't riding in it after that horror picture...wonder if 20mm chewed up the Blenie frame just as bad.. :huh
Maybe a review of aircraft design philosophy versus survivability philosophy by country is in order.
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Would it have mattered to the volume of expanding gasses from the explosion if they had punched a hole in the skin next to the round before it was detonated?
Maybe a review of aircraft design philosophy versus survivability philosophy by country is in order.
I could imagine that for example a Wellington would react differently and had much better survivability against such a "hit" in the rear fuselage area, due to it's geodetic design.
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Spitfire with the MK108 exploded inside the fuselage:
(http://mccoy.nu/109/spitfire_vs_mk108_test.jpg)
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Would it have mattered to the volume of expanding gasses from the explosion if they had punched a hole in the skin next to the round before it was detonated?
This is a good question,from what I read they located the shell in the center of the fuselage,held in place by wires.
If you look at both pix,spit and Blen you'll notice an almost perfectly place explosion to obtain maximum damage.
However if the shell was traveling at any speed it's unlikely that the shell would explode dead center of the fuselage and it's unlikely that the damage would be so symmetrical.Still it gives us a good idea about the amount of damage the round is capable of inflicting.
:salute
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Is there like a Horror pictures of the WW2 Airwar with all these photos somewhere? Or are there WW2 war studies with photographs and documentation for air to air munitions that you are accessing? Does anyone have a link to a german gun camera showing a 30mm hitting an aliied fighter? I've seen the bomber ones. Bombers absorb them for awhile.
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This would be a good place to start.
http://www.quarry.nildram.co.uk/
but I just use a search for weapons testing and see where it leads me.
Tony Williams used to contribute to the forum and his site covers just about any weapon/gun thats been used.
He has a great article on what would be the ultimate WW2 aircraft weapon,his conclussions or quite interesting.
:salute
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See Rule #6
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See Rule #6
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Alto if i use a bit of brain power. A lot of these pictures are of damage that happened on the ground with the aircraft standing still. Now if you think about it the damage to the aircraft in the air can be reduced due to a certain factors.
1) both air craft are moving at high speed so the cannon and bullet rounds ( projectile's ) have the force of oncoming wind and air resistance to fight. I.E the wake of air left behind by the aircraft in front, the gforce's of the aircraft that is firing the rounds. these are some of the force's that the projectile rounds have to deal with to get to the target. Thus they may affect the speed of the oncoming round by a small fraction.
2) The fact that the lead aircraft that you will be firing at wont be stationary it's moving trying to keep you from hitting it. thus you may only get around 20% of the burst of fire from your gun's impacting on the target.
3) If the target is on the ground and stationary we all know that a 3 second burst from a 30mm or a 20mm cannon will cause the damage that we see in these pictures. As logically around 85% of a 3 second burst will impact on target. Thus the damage is more concentrated to one spot.
4) The film in the first post also could be the invention of the explosive cannon round. Its really a small version of a high explosive shell used by tank's and artillery gun's. And was invented by the British and American's for armament to our ground attack aircraft ( after D-Day ) i.e the Typhoon , Tempest and to be developed for the P-47 as a backup for once the pilot had used all his rocket's for tank busting attacking an airfield he can still do some pretty good damage.
Now i know there is probally some people out there in the forum's who will disagree with me but hey before you say anything let's research it more because if high explosive cannon shell's where part of WW2 armament then we may be-able to Get them implemented in the game as another choice of weapon :)
Thanks BulletVI
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See Rule #6
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Did you look at the pic of the Blenheim or spit? those were the result of 1 30mm round from a Mk108 that was placed in the fuselage then electrically ignited.
So while you may be correct that the effects may be different if fired from an actual weapon,the results of these "tests" are pretty obvious.
BTW we already have these type of weapons and effects ingame,just try a K4 or 110G with the 30mm and see for ourself.
:salute
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1) both air craft are moving at high speed so the cannon and bullet rounds ( projectile's ) have the force of oncoming wind and air resistance to fight. I.E the wake of air left behind by the aircraft in front, the gforce's of the aircraft that is firing the rounds. these are some of the force's that the projectile rounds have to deal with to get to the target. Thus they may affect the speed of the oncoming round by a small fraction.
Velocity of the shell has little effect on the destructive power of a HE shell.
2) The fact that the lead aircraft that you will be firing at wont be stationary it's moving trying to keep you from hitting it. thus you may only get around 20% of the burst of fire from your gun's impacting on the target.
3) If the target is on the ground and stationary we all know that a 3 second burst from a 30mm or a 20mm cannon will cause the damage that we see in these pictures. As logically around 85% of a 3 second burst will impact on target. Thus the damage is more concentrated to one spot.
In the original poster’s film the MK 108 30mm cannon fires a single round. A single round did that damage, not a burst.
4) The film in the first post also could be the invention of the explosive cannon round. Its really a small version of a high explosive shell used by tank's and artillery gun's. And was invented by the British and American's for armament to our ground attack aircraft ( after D-Day ) i.e the Typhoon , Tempest and to be developed for the P-47 as a backup for once the pilot had used all his rocket's for tank busting attacking an airfield he can still do some pretty good damage.
The weapon is a MK 108 30mm cannon used by the Germans in WWII. It was part of the armament of many Luftwaffe aircraft in 1944-45, including the Bf 109, Bf 110, Fw 190, Me 262, Me 163, Me 410, and several others.
Now i know there is probally some people out there in the forum's who will disagree with me but hey before you say anything let's research it more because if high explosive cannon shell's where part of WW2 armament then we may be-able to Get them implemented in the game as another choice of weapon :)
No research necessary; explosive shells are modeled for all cannon armed planes in the game except the tank-killers which used AP.
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Did you look at the pic of the Blenheim or spit? those were the result of 1 30mm round from a Mk108 that was placed in the fuselage then electrically ignited.
So while you may be correct that the effects may be different if fired from an actual weapon,the results of these "tests" are pretty obvious.
BTW we already have these type of weapons and effects in game,just try a K4 or 110G with the 30mm and see for ourself.
:salute
Oh yes i know we already have the best weapon damage effect's that computer's can give today. But if you read closely i was saying and i should have went into a bit more detail. These where probably tests to see what the damage from an exploding 30mm or 20mm round can do to effect more damage on ground targets i.e static aircraft. As with most cases if you strafe a static aircraft the only way of purely destroying it is to aim for the fuel tank's. now that can be quite hard to do as is not moving and your moving at around 350mph. So they probably picture's of tests to see if an exploding cannon shell Doe's more damage to static target's. And it doe's.
And in North Africa it was proved very effective with the Hurricane IIB with the 2 30mm cannons under the wing. They fired an early form of explosive cannon shells that would detonate on impact. Later Typhoons And other ground attack Aircraft where equip ed with Explosive cannon shell's that where time delayed by means of a double tip on the cannon round simple an effective. Once the cannon round pierced the skin of an aircraft the first layer would crumble thus exploding the actual cannon shell so when that would hit the other side or a strut on the frame Boom Big explosion.
The Germans in some case's after D-Day actually thought they were being shelled as well as attacked from the air. :)
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Velocity of the shell has little effect on the destructive power of a HE shell.
In the original poster’s film the MK 108 30mm cannon fires a single round. A single round did that damage, not a burst.
The weapon is a MK 108 30mm cannon used by the Germans in WWII. It was part of the armament of many Luftwaffe aircraft in 1944-45, including the Bf 109, Bf 110, Fw 190, Me 262, Me 163, Me 410, and several others.
No research necessary; explosive shells are modeled for all cannon armed planes in the game except the tank-killers which used AP.
OK :salute :salute
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OK :salute :salute
Everything Die Hard said was true,however the same cant be said for you.The Hurricane IIB never was equipped with 30mm cannon,maybe 40mm but never 30mm.
:salute
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Everything Die Hard said was true,however the same cant be said for you.The Hurricane IIB never was equipped with 30mm cannon,maybe 40mm but never 30mm.
:salute
OK so the Hurricane was a guess on the cannon size.
But also in relation to the picture's these could also be tests of Germany's 30mm cannon from captured or downed Me 109's that where forced down over the UK. As a test bead to design much more destructive cannons than Germany. Remember we would have had an abundance of German Me 109 F's and earlier model's even probally later model's of the Me 109. From a few daylight sneak raid's and so forth.
And the germans in their own rights's where probally testing their weapon's on captured or downed aircraft from the UK .
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Yes both sides did extensive tests to see weapon effectiveness.
IIRC the germans concluded 3 to 5 hits from a 30mm cannon would down a 4 engine heavy,whereas it took 20 or more 20mm to do the same.
The US concluded that the hisp.20mm was equal to roughly 3 50cals so a typhoon would have twice the firepower of a P51.
Most the pix shown were done after hostilities ceased and there was an abundance of weapons to test.
:salute
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General reading at the Army Office of Medical History Wound Ballistics report. A true horror show.
http://history.amedd.army.mil/booksdocs/wwii/woundblstcs/default.htm
Interesting is the german MG151/20 He round has aprox 18grams of HE opposed to the Mk108 30mm round's aprox 72- 85grams of HE. From what I can find the 20mm took 4-5 rounds to kill a single engine fighter while I cannot find any statement to the fact; I suspect one round of 30mm HE would sufice on most fighters. As for bombers here is a line from a Tony Williams discussion:
Tests carried out at Rechlin (where most of the Luftwaffe aircraft and weapons tests were done) showed that with a "M-Shell" with 85 grains of explosive, five hits COULD destroy a B-17 or B-24 bomber.
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General 30mm information:
The resulting low muzzle velocity was the MK 108's main shortcoming, with the result that its projectile trajectory was seriously affected by bullet drop after a comparatively short range—41 m (135 ft) of drop in the first 1,000 m (3,300 ft) of range. The long time of flight and curved trajectory strongly reduced the usefulness of the MK 108 against maneuvering targets like fighters; it was designed for use against bombers. Even against these, attacks had to be pressed home to close range, which was particularly challenging for fast fighters like the Me 262, which risked colliding with the target if their approach speed was too high.
Personal Note:
Guess collisions to get gun solutions were a real problem in WW2 and should be expected as a reality in the Aces High simulator environment.
Even against these, attacks had to be pressed home to close range, which was particularly challenging for fast fighters like the Me 262, which risked colliding with the target if their approach speed was too high.
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Yes both sides did extensive tests to see weapon effectiveness.
IIRC the germans concluded 3 to 5 hits from a 30mm cannon would down a 4 engine heavy,whereas it took 20 or more 20mm to do the same.
The US concluded that the hisp.20mm was equal to roughly 3 50cals so a typhoon would have twice the firepower of a P51.
Most the pix shown were done after hostilities ceased and there was an abundance of weapons to test.
:salute
Ah yes i read about that but we also have to remember that due to all the testing that was achieved and from it the development of the armor piercing explosive cannon shell led to the development of the vicker's cannon and the need for less ammo to store on today's fighter's.
That's why the like's of the Su27 and MiG 29 only carry inefect of 150 rounds its due to the destructive power of each cannon shell. The same was found to be with western aircraft as-well they carry only 300 -900 cannon rounds depending on type of aircraft. Aircraft with the cannon version of the mini gun i have no idea about ???
:salute :rock
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:headscratch:
What?
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:headscratch:
What?
OOOPPPSSSS my reply has put it self in with the quote lol :lol :rofl
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No, not that.
The reason modern aircraft only carry a couple hundred rounds of ammo is because the primary weapon of every fighter aircraft is a missile.
And because of the disaster of the dogfighting is dead theorum, they put guns on fighters in case they get into a knife fight situation.
And because of the high speeds of jet dogfighting and the high rate of fire of the vulcan cannons, they only need a very, very short burst of rounds to inflict lethal damage to an aircraft.
950 rounds 20mm cannon. Gatling gun 6,000 rounds per minute. 100 rounds per second. 9 seconds of total firing.
That's enough to get some work done. And 100 rounds per second with 20mm cannon. :O Think of what that can do to a plane.
The rounds hit a bit harder but are not signifigantly better. Well, some rounds hit much harder but you catch my drift.
And if you really think about it, we carry alot more cannon then WWII planes.
Tempest = 600 rounds 20mm cannon, Hurri 2C = 180 rounds cannon, F-15C = 950 rounds cannon.
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No, not that.
The reason modern aircraft only carry a couple hundred rounds of ammo is because the primary weapon of every fighter aircraft is a missile.
And because of the disaster of the dogfighting is dead theorum, they put guns on fighters in case they get into a knife fight situation.
And because of the high speeds of jet dogfighting and the high rate of fire of the vulcan cannons, they only need a very, very short burst of rounds to inflict lethal damage to an aircraft.
950 rounds 20mm cannon. Gatling gun 6,000 rounds per minute. 100 rounds per second. 9 seconds of total firing.
That's enough to get some work done. And 100 rounds per second with 20mm cannon. :O Think of what that can do to a plane.
The rounds hit a bit harder but are not signifigantly better. Well, some rounds hit much harder but you catch my drift.
And if you really think about it, we carry alot more cannon then WWII planes.
Tempest = 600 rounds 20mm cannon, Hurri 2C = 180 rounds cannon, F-15C = 950 rounds cannon.
Ah so it's true you do learn somit new every day
:salute
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Ah so it's true you do learn somit new every day
:salute
In your case, something new in 53 minutes... lol :neener:
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Tempest = 600 rounds 20mm cannon, Hurri 2C = 180 rounds cannon, F-15C = 950 rounds cannon.
N1K2-J = 900 rounds 20mm cannon, F4U-1C = 932 rounds 20mm cannon, Beaufighter = 1200 rounds 20mm cannon. :P
All joking aside, modern aircraft are vastly more capable.
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In your case, something new in 53 minutes... lol :neener:
In your case every 2 years :lol :neener: :neener: :neener: :neener: :neener:
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N1K2-J = 900 rounds 20mm cannon, F4U-1C = 932 rounds 20mm cannon, Beaufighter = 1200 rounds 20mm cannon. :P
All joking aside, modern aircraft are vastly more capable.
Oh damn, I forgot about those planes.
The majority of the cannon armed planes have less cannon than modern planes.
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From some other thread:
Here is a photo of that Mosquito PR.Mk XVI that was hit by 2-4 30mm rounds from an Me262.
(http://members.arstechnica.com/x/karnak/MossMk108Dam.jpg)
...That subsequently Returned To Base.
wrongway
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Alto if i use a bit of brain power. A lot of these pictures are of damage that happened on the ground with the aircraft standing still. Now if you think about it the damage to the aircraft in the air can be reduced due to a certain factors.
As much, if there are certain factors in the air that are not present in ground testings which may work against the potential of the round, the opposite also applies: there are factors which may increase the damage, were it in mid-air. Usually, the two adequately offset each other so a theoretical conjecture on the difference between a ground testing and in-flight testing is largely pointless.
1) both air craft are moving at high speed so the cannon and bullet rounds ( projectile's ) have the force of oncoming wind and air resistance to fight. I.E the wake of air left behind by the aircraft in front, the gforce's of the aircraft that is firing the rounds. these are some of the force's that the projectile rounds have to deal with to get to the target. Thus they may affect the speed of the oncoming round by a small fraction.
This factor is more or less offset by the fact that the speed of the plane on which the gun is mounted, actually adds that much more kinetic energy to the round being fired in the form of speed. Unless the plane is already travelling at speeds close to the terminal velocity of the round fired (which is impossible), its largely non-issue.
2) The fact that the lead aircraft that you will be firing at wont be stationary it's moving trying to keep you from hitting it. thus you may only get around 20% of the burst of fire from your gun's impacting on the target.
On the other hand, maneuvering often exposes a larger/broader surface profile which makes it easier to land shots on, and makes shots that landed more effective. So again, this factor is also offset.
3) If the target is on the ground and stationary we all know that a 3 second burst from a 30mm or a 20mm cannon will cause the damage that we see in these pictures. As logically around 85% of a 3 second burst will impact on target. Thus the damage is more concentrated to one spot.
Considering the fact that the rounds fired are HE, and not AP or API, this also makes the assumption pointless. If the shots land more spread out, it simply means a wider area of the skin is torn apart, and thus makes it equally likely to cause immediate structural failures.
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As much, if there are certain factors in the air that are not present in ground testings which may work against the potential of the round, the opposite also applies: there are factors which may increase the damage, were it in mid-air. Usually, the two adequately offset each other so a theoretical conjecture on the difference between a ground testing and in-flight testing is largely pointless.
This factor is more or less offset by the fact that the speed of the plane on which the gun is mounted, actually adds that much more kinetic energy to the round being fired in the form of speed. Unless the plane is already travelling at speeds close to the terminal velocity of the round fired (which is impossible), its largely non-issue.
On the other hand, maneuvering often exposes a larger/broader surface profile which makes it easier to land shots on, and makes shots that landed more effective. So again, this factor is also offset.
Considering the fact that the rounds fired are HE, and not AP or API, this also makes the assumption pointless. If the shots land more spread out, it simply means a wider area of the skin is torn apart, and thus makes it equally likely to cause immediate structural failures.
Nice to see a second / Different opinion there haveing read it i believe we are both correct on some fact's and other's we can have a good old debate aboot :) :salute
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Later Typhoons And other ground attack Aircraft where equip ed with Explosive cannon shell's that where time delayed by means of a double tip on the cannon round simple an effective. Once the cannon round pierced the skin of an aircraft the first layer would crumble thus exploding the actual cannon shell so when that would hit the other side or a strut on the frame Boom Big explosion.
The Germans in some case's after D-Day actually thought they were being shelled as well as attacked from the air. :)
The RAF and USAAF armorers manuals for the Hispano contain no reference to ANY specific delayed action fuses.
There were two basic fuse types for Hispano ammunition, Mk I and Mk II. Both were 'Superquick' instantaneous percussion fuses, although the various sub-types of fuses did vary slightly in the sensitivity and speed. The US manual notes the MK II fuse is more sensitive than the Mk I.
US/RAF HE, HE-I shell types had instantaneous fuses. When you look at pictures of the rounds its obvious, as they have truncated, squared off nose sections.
AP and ball rounds had no fuses
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Nice to see a second / Different opinion there haveing read it i believe we are both correct on some fact's and other's we can have a good old debate aboot :) :salute
You have yet to be correct on anything in this thread, and your knowledge of aircraft, weapons, ballistics and history is atrociously poor to say the very least.
There is going to be some difference in the resulting damage between an explosive shell placed inside an enclosed space then detonated and one that has been fired from a weapon 300 yards away. With an impact fuse, and a shaped charge the damage created upon impact is going to be closer to the surface area. The damage shown in those photos of the Blenheim and Spitfire would be more like the damage cause by a delayed fuse round which would penetrate the surface and explode inside the cavity. It is possible that a Mk-108 round would do that if it passed through an opening and hit something internally or failed to explode until it hit an internal structure.
Reported 20mm damage on B-17s
(http://www.daveswarbirds.com/b-17/photos/body/side2.gif)
(http://www.daveswarbirds.com/b-17/photos/tail/tailgun1.gif)
(http://www.daveswarbirds.com/b-17/photos/body/balltur.jpg)
Unknown caliber but reported damage from unspecified models of FW-190s
(http://www.daveswarbirds.com/b-17/photos/tail/tail3.jpg)
(http://www.daveswarbirds.com/b-17/photos/tail/rudder3.gif)
Reported damage from a German "Jet"
(http://www.daveswarbirds.com/b-17/photos/wings/aileron120.jpg)
I don't think the damage effects of the 20 and 30 mm HE rounds are modelled in AH as well as some think. They act more like large caliber bullets than explosives.
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[...]
I don't think the damage effects of the 20 and 30 mm HE rounds are modelled in AH as well as some think. They act more like large caliber bullets than explosives.
But somehow you can destroy airplanes sitting on the runway/ground without a single direct hit from 20 or 30mm HE rounds.
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You have yet to be correct on anything in this thread, and your knowledge of aircraft, weapons, ballistics and history is atrociously poor to say the very least.
That is your opinion we all have different history you may know some things i dont and vice versa. Piece of advice stop trying to put other people down on your posts and work with them to better the game remember i have been reading from wikipedia and a few other sight's after googling the topic of destructive power of the 30mm and 20mm canon so i am sorry if in trying to click from one tab back to the other has coused me not to put in some bits and bob's of info from these page's but hey when you try to give a short explination of your answer from a page of info that contains over 6000 word's its bound to not sound totally correct.
And for your info i have studied WW1 And WW2 history for year's but never been intrested in the damage aspect of the armament of the Gun's on the aircraft. More of what they did and took part in. But as i have said in the above paragraph and in previous post's has been correct to some degree. So maybe its you thats 90% wrong and 10% right. And maybe you cant handle being wrong so you decied to put other people down to cover up for you'r inadiquicie's as a human being. And oh by the way picture's of damge to aircraft after the raid's is flawed in my opinion. As you do not Know if or around the same area as the damage shown has been previously patched by ground crew. thus resulting in a drop of srtuctual strength in that area by a small amount/margine. thus resulting in possible more damage the next time that area get's hit by cannon fire or anti aircraft fire.
Now i know you will have something to say about this. But i'd advise you to stay quiet :) :aok
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That is your opinion we all have different history you may know some things i dont and vice versa. Piece of advice stop trying to put other people down on your posts and work with them to better the game remember i have been reading from wikipedia and a few other sight's after googling the topic of destructive power of the 30mm and 20mm canon so i am sorry if in trying to click from one tab back to the other has coused me not to put in some bits and bob's of info from these page's but hey when you try to give a short explination of your answer from a page of info that contains over 6000 word's its bound to not sound totally correct.
And for your info i have studied WW1 And WW2 history for year's but never been intrested in the damage aspect of the armament of the Gun's on the aircraft. More of what they did and took part in. But as i have said in the above paragraph and in previous post's has been correct to some degree. So maybe its you thats 90% wrong and 10% right. And maybe you cant handle being wrong so you decied to put other people down to cover up for you'r inadiquicie's as a human being. And oh by the way picture's of damge to aircraft after the raid's is flawed in my opinion. As you do not Know if or around the same area as the damage shown has been previously patched by ground crew. thus resulting in a drop of srtuctual strength in that area by a small amount/margine. thus resulting in possible more damage the next time that area get's hit by cannon fire or anti aircraft fire.
Now i know you will have something to say about this. But i'd advise you to stay quiet :) :aok
Actually Bullet, it's not an "opinion", it's a fact. As in everything you have tried to state as fact has been false, and I'm not the only one who has pointed that out to you regardless of your selective memory, it's in black and white on this thread. Not even Wikipedia has that much false information in it.
Ah yes i read about that but we also have to remember that due to all the testing that was achieved and from it the development of the armor piercing explosive cannon shell led to the development of the vicker's cannon and the need for less ammo to store on today's fighter's.
That's why the like's of the Su27 and MiG 29 only carry inefect of 150 rounds its due to the destructive power of each cannon shell. The same was found to be with western aircraft as-well they carry only 300 -900 cannon rounds depending on type of aircraft.
Not even close to reality. Testing and development of armor piercing ammuntion was started in the 1850s, and years before WWI, armor piercing high explosive ammuntion was introduced for nearly all cannons, especially naval guns. And your Vickers cannon was developed as an anti-aircraft weapon long before those WWII tests you supposedly read about. None of it has anything to do with the number of cannon rounds found in modern jet fighters, it was supersonic flight and the invention of heat seeking missiles.
But also in relation to the picture's these could also be tests of Germany's 30mm cannon from captured or downed Me 109's that where forced down over the UK. As a test bead to design much more destructive cannons than Germany. Remember we would have had an abundance of German Me 109 F's and earlier model's even probally later model's of the Me 109. From a few daylight sneak raid's and so forth.
And the germans in their own rights's where probally testing their weapon's on captured or downed aircraft from the UK.
Again, waaaay out in left field. The only thing you got partially right was the testing of the Mk-108, but it wasn't from downed or captured 109s. There was no "abundance" of intact 109s found in England during WWII. The 109F did not use the Mk-108 30mm or any other 30mm, ever. It had the MG151/20 which was an upgrade from the earlier MG FF or MG FF/M 20mm found in the earlier 109s. Lastly, the Germans and every other country tested the effectiveness of their weapons on objects other than captured or destroyed enemy equipment long before they were put into production.
Shall I continue, or would you like to thrill me with more of your vast knowledge? FYI for future reference, wikipedia should be the very last place you use for reference material.
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Actually Bullet, it's not an "opinion", it's a fact. As in everything you have tried to state as fact has been false, and I'm not the only one who has pointed that out to you regardless of your selective memory, it's in black and white on this thread. Not even Wikipedia has that much false information in it.
Not even close to reality. Testing and development of armor piercing ammuntion was started in the 1850s, and years before WWI, armor piercing high explosive ammuntion was introduced for nearly all cannons, especially naval guns. And your Vickers cannon was developed as an anti-aircraft weapon long before those WWII tests you supposedly read about. None of it has anything to do with the number of cannon rounds found in modern jet fighters, it was supersonic flight and the invention of heat seeking missiles.
Again, waaaay out in left field. The only thing you got partially right was the testing of the Mk-108, but it wasn't from downed or captured 109s. There was no "abundance" of intact 109s found in England during WWII. The 109F did not use the Mk-108 30mm or any other 30mm, ever. It had the MG151/20 which was an upgrade from the earlier MG FF or MG FF/M 20mm found in the earlier 109s. Lastly, the Germans and every other country tested the effectiveness of their weapons on objects other than captured or destroyed enemy equipment long before they were put into production.
Shall I continue, or would you like to thrill me with more of your vast knowledge? FYI for future reference, wikipedia should be the very last place you use for reference material.
Talk to the HAND you obviously are a person who thinks he is right from the start
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Talk to the HAND you obviously are a person who thinks he is right from the start
LMAO, again false but nice try.
Let me know when you find something you do know something about.
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LMAO, again false but nice try.
Let me know when you find something you do know something about.
But he is an aircraft engineer... ;)
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(http://www.xs4all.nl/~robdebie/me163/images/large/weapon27.jpg)
There is not shape charged effect from this round at all, that is just reinforcing for the driving band.
There can be no shaped charge effect without fusing the round to ignite at the base of the round.
Bullet, asking instead of declaring is a better bet when you are new to a subject. Just ask Gyrene, he knows.
We are all interested in this stuff, and we are all learning about it. But declaring things what are off base just leads to arguments, asking things that are off base just leads to discussion.
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(http://www.xs4all.nl/~robdebie/me163/images/large/weapon27.jpg)
There is not shape charged effect from this round at all, that is just reinforcing for the driving band.
There can be no shaped charge effect without fusing the round to ignite at the base of the round.
Bullet, asking instead of declaring is a better bet when you are new to a subject. Just ask Gyrene, he knows.
We are all interested in this stuff, and we are all learning about it. But declaring things what are off base just leads to arguments, asking things that are off base just leads to discussion.
Wasnt declareing i just couldnt find a lot of info on it so i was happy for any correction's on the subject
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(http://www.xs4all.nl/~robdebie/me163/images/large/weapon27.jpg)
There is not shape charged effect from this round at all, that is just reinforcing for the driving band.
There can be no shaped charge effect without fusing the round to ignite at the base of the round.
Bullet, asking instead of declaring is a better bet when you are new to a subject. Just ask Gyrene, he knows.
We are all interested in this stuff, and we are all learning about it. But declaring things what are off base just leads to arguments, asking things that are off base just leads to discussion.
The germans made the projectile by a drawing method so a thin but strong steel shell was created. You will notice in the cross section a gradual taper of a darker material from the base towards the meplat. That material has a metal plug screwed into it. The thinest section of the round is in the first third down from the fuse which is acting as the meplat. Just below the fuse in the first sixth of the drawn casing the steel is very thick for a single purpose. If it were as thin there as below in the first third you run into a real danger of a dud because the fuse would simply be pused down into the softer body of explosive. Or, excelleration leaving the barrel could cause premeture detonation. With the thinest section of the casing in the first third at the top of the explosive column, the casing will ruptur there intitialy creating a shaped blast forward and outward.
You can look at the projectile as a pipe bomb. A cap was screwed on one end with lead poured in to a quarter of the pipes volume. The rest is flilled with an explosive mixture and the second cap screwed on. When it detonates which end is the path of least resistance for the hot gasses to expand? Remember, the micro air gaps at the end poured with lead are completly sealed. Granted the explosion is in a nano second and shrapnel will eventualy be thrown everywhere but, where will the intial bursting force of the hot gasses concentrate and vector the blast along?
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Then please explain the spherical blast patterns of the British static tests posted in this thread?
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How were the rounds detonated in the static British tests?
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How were the rounds detonated in the static British tests?
(http://www.airwar.ru/image/i/weapon/mk108blenheim.jpg)
This one was suspended inside the airframe then detonated I think.
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And what type of detination was it???
Was it detonated by fuse ?
By time pencil detonator's ?
How as i think that certain forms of detonation also have some small force dehind them but hey who know's.
anyone know of an explosive's expert ???? :D :salute
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(http://www.airwar.ru/image/i/weapon/mk108blenheim.jpg)
This one was suspended inside the airframe then detonated I think.
Yeah, I understand that, but how did they detonate them? Electrical, blasting cap, etc.? TW probably knows.
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No more educated speculation.
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It's from "Flying Guns of World War II; Development of Aircraft guns, ammunition, and installations 1933-1945" by Anthony G. Williams and Emmanuel Gustin.
Weapons
"The German approach represented a completely different philosophy from that of the USAAF. Instead of using the kinetic energy of large numbers of high-velocity AP bullets to destroy the target, the Luftwaffe relied on the blast effect of large quantities of HE detonating within the structure. Both approaches seemed to work well, but of course the USAAF generally only had to attack enemy fighters (for which HMGs were usually powerful enough), not bombers. By the end of the war, the M-Geschoss had become the standard German type of aircraft cannon projectile, and it was widely adopted by other air forces post-war. Hollow-charge projectiles were developed for the 30mm guns, but it appears that they did not see service; in fact, only in recent years have the problems of using such technology in small-calibre cannon ammunition been solved.
As we have seen, the British were systematic in testing whatever German guns and ammunition they could get hold of against realistic aircraft targets, and they concentrated hard on the 20mm guns, particularly with HE ammunition. They discovered the following:
* In firing trials against bullet-proof Triplex glass at a range of 46m and a striking angle of 45 degrees, an MG-FF firing HE/T projectiles could penetrate 3.8 cm glass but not 6.35 cm.
* HEI with instant-action fuse fired from an MG-151/20 at 183m would detonate on a Perspex canopy, with the fragments making little impression on the armour behind.
* The same ammunition set light to a self-sealing wing fuel tank of a Blenheim light bomber with three shots out of eight.
* The same ammunition could be protected against by 12mm face-hardened armour, or just 6.6mm homogeneous armour (which was less brittle.)
* For comparison purposes a few rounds of 20mm Hispano HEI were fired at the same target as above. The test report commented that although the German HEI (M-Geschoss) contained more explosive, the powerful Hispano stood more chances of doing serious damage - such as the breaking of spar flanges - or of reaching the fuel tanks.
* A test of German 20mm incendiary/tracer ammunition showed that it was remarkably effective, with 17 out of 22 rounds hitting the usual Blenheim wing tank causing fires; but 14 rounds ignited prematurely and flashed at the muzzle, and these proved ineffective. The ammunition was judged to be faulty.
The 30mm 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. The Germans discovered that a wing hit on a B-17 resulted in a hole of 100 x 175 cm. It was noted that the ammunition did not have much effect on heavy bomber fuselages (presumably because of the large volume for th 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 on the construction of the aircraft. Stressed-skin alloy monococque structures were most vulnerable to being blown apart. Steel structures clad with thin aluminum were less affected as the cladding quickly split, releasing the pressure before it had much time to damage the structure, and fabric-covered structures, such as the Wellington bomber, 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. Protective measures could be taken against blast effects, and it was discovered that a 20mm thick strong rubber foam mat lining compartments significantly reduced the effect.
The British and American 20mm Hispano HE/HEI shells were conventional thick-walled designs with more limited HE capacity but considerable kinetic energy. They also produced larger and heavier fragments than the M-Geschoss when they burst, which would have carried further and penetrated more deeply. The British Mk 1.z HE shell was expected to a blow a hole between 75mm and 200mm in diameter in 12mm armour plate, while scattering shell fragments up to 5 meters. British tests of the HEI revealed that coolant, lubricant and fuel systems would be holed by fragments resulting from hits on engine cowlings, and detonation some 75mm from a self-sealing tank would result in a hole over 50mm in diameter, causing leakage of 1,900 litres per hour. Whether a Hispano HEI or a 20mm M-Geschoss would do most damage depended on the aircraft being attacked, and exactly where the shell detonated.
The Soviets selected a relatively light projectile weight of 91 - 99 grams for the ShVAK's 20 x 99R cartridge, although they did not have the benefit of M-Geschoss technology. Heaviest was the API Type BZ, which had a sub-calibre hard steel penetrator, the jacket tip being filled with incendiary material. The HEI Type OZ had a very small HE capacity, representing only around six percent of the weight. The 23mm projectiles used in the Vya and the NS-23 went to the other extreme, weighing an impressive 200 grams. The type BZ API was still steel-cored, with 6.6 grams of incendiary compound in the tip, while the Type OZT HEI/T, and the 37mm HE shell, again had only a small percentage of their weight devoted to HE. They were clearly expected to inflict most damage by fragmentation rather than blast effect; British tests of the Vya HEI revealed that blast effects were similar to those of hte 20mm Hispano HEI.
Japanese cannon projectiles varied between the heavy (IJN 20mm Type 99 projectiles weighed around 128 grams, the IJA's Ho-1 and Ho-3 up to around 127-136 grams) to the very light (IJA 20mm Ho-5 as little as 79 grams). AP projectiles were of the cannon type (I.E. Solid steel) rather than using sub-calibre cores. HE shells generally had a modest filling ratio, although the little 79 grams Ma 202 HEI used in the Ho-5 managed an impressive - for a non-M-Geschoss - fifteen percent change/weight figure by virtue of its fuseless design: where a fuse would normally be was a PETN HE exploder (the equivalent of the more powerful Ho-1 and Ho-3 being the 109 gram HEI). Larger cannon shells such as the IJN 30mm Type 2 HE and the 37mm shell used in the Ho-203 and Ho-204 also varied in their change/weight ratios.
The frequent use of unprotected PETN exploders in Japanese ammunition must have represented a significant handling risk, and does not appear to have been copied by other countries."
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Armour penetration
"Comparisons between the penetration achieved by different armour-piercing cartridges are problematic for several reasons. First, penetration figures are often quoted at different distances and striking angles (incidentally, striking angles in this work are all quoted using the convention that the most favourable angle for penetration, perpendicular (or 'normal') to the armour, is measured as 90 degrees; some other conventions have described this as 0 degrees). Much less obviously, different qualities of armour are sometimes assumed. There have also been various national definitions of 'penetration'; some (e.g. the US) specified that 50 percent of the shots fired have to pass through the target, others required signficantly higher percentages, or did not require the shot to pass completely through the target. Finally, AP performance was usually measured on the ground. When fired from an aircraft, the actual figure would be slightly reduced in a tail chase due to increased air resistance (less of an effect at high altitude), but would be increased when firing at ground targets because the speed of the aircraft was added to the muzzle velocity, and considerably increased in a head-on attack.
In addition to these problems, the actual performance of AP projectiles in battle can vary considerably from that achieved on test. In particular, passing through the thin aluminium aircraft skin can induce yaw, i.e. disturb the straight flight of the projectile away from travelling point-first, so that it fails to hit the armour head-on, thereby significantly reducing its penetrative abilities. In fact the degree of obstruction caused by aircraft structures is such that armour much thinner than theory indicated would be necessary was often found to give satisfactory results.
The most exhaustive tests during the Second World War seem to have been carried out in Germany. Official penetration curves for 7.92mm AP rounds tested in 1942 are worth examining in detail because they reveal the variations wihch can occur. The SmK-v (Spitzgeschoss mit Stahlkern verbessert, improved pointed bullet with steel core) achived the following:
At 100 meters:- 12mm/90 degrees - 8mm/60 degrees - 3.5mm/30 degrees
At 300 meters:- 9mm/90 degrees - 6mm/60 degrees - 3mm/30 degrees
At 600 meters:- 6mm/90 degrees - 3.5mm/60 degrees - 1.5mm/30 degrees
However, if the bullet first penetrated at 3mm dural (light alloy) aircraft skin angled at 70 degrees, armour penetration at 100 meters dropped to 4mm/90 degrees, 3mm/60 degrees and 2.5mm/30 degrees.
These results are supported by tests carried out by the British in January 1941 to compare British and German rifle-calibre steel-cored AP ammunition. The performance of the .303 (11.28 grams at 735 meters/second) and the 7.92mm (of unspecified type, but measured at 11.53 grams at 788 meters/second) was first tested against 'homogeneous hard armour'. The thickness necessary to achieve immunity from this ammunition at 183 meters (200 yards) was 12.0 mm for the .303 in, 12.5mm for the 7.92mm, when striking 'at normal' to the armour (i.e. at 90 degrees). The British ammunition was significantly worse when the striking angle changed to 70 degrees; only 6.6mm was needed for immunity in comparion with 8.9mm to protect against the German round.
The test then changed to shooting at the rear of the long-suffering Bristol Blenheim at the same distance, involving penetrating the rear fuselage before reaching the 4 mm armour plate protecting the rear gunner, which was angled at 60 degrees to the line of fire. The results in this case were reversed: 33 percent of the .303 in rounds reached the armour and 6 percent penetrated it. In contrast, only 23 percent of the 7.92mm bullets reached the armour, and just 1 percent penetrated. The British speculated that the degree of stability of the bullets (determined by bullet design and the gun's rifling) might have accounted for these differences.
Continuing with the German ammunition (for which more detailed records seem to survive than any other nation's during the period), it is instructive to compare some of the standard AP types in different calibres. The little 13 x 64B Pzgr for the MG-131 was capable of penetrating 17mm/100 meters/90 degrees, but this dropped to just 10mm/60 degrees and 4mm/30 degrees (equivalent figures at 300 meters being 11mm/90 degrees and 7mm/60 degrees). On the other hand, the consequences of hitting the dural plate were negligible, only reducing penetration by 1 or 2 mm.
Before turning to the 20 mm cannon it is worth mentioning the performance of the .50 in Browning. The official requirement for the M2 AP way to penetrate 22mm steel at 183 meters (200 yards) (the M8 API was expected to match this figured at 92 meters). The striking angle is not specified but assumed to be 90 degrees. Official US tables for the M2 show penetration at 300 meters as follows: 21mm/90 degrees, 13mm/60 degrees, 5mm/30 degrees.
These measurements were to the USN criterion which called for 50 percent of shots to penetrate. British tests at 183m determined that the M2 would penetrate 21mm at 0 degrees angle of yaw (i.e. the bullet was flying perfectly straight), but this dropped to 15mm with only 10 degrees of yaw (such as might be caused by passing through an aircraft's skin before hitting the armour). Further tests at 90 meters firing through a heavy bomber fuselage demonstrated an ability to penetrate between 14 and 20 mm when firing at angles of between 57 and 77 degrees. German tests credited the M2 with a penetration of 25mm/100 meters/90 degrees, falling to only 10mm after passing through the dural skin (the 12.7mm Berezin API was even worse affected, falling from 25mm to 8.5mm). Taking the effects of typical ranges, striking angles and fuselage structures into account, it seems likely that the practical penetration of either the M2 or M8 was in the region of 10-15 mm in normal circumstances. This was generally adaquate for dealing with aircraft armour, although it should be noted that Finnish pilots using Brewster Buffalos armed with .50 in Brownings reported considerable difficulty in shooting down Soviet fighters from directly behind, and recommended attacking from a slight angle in order to fire past the rear armour plate.
German 20mm ammunition did not have sufficient velocity to justify the use of Hartkernmunition, so the AP types were plain steel with some incendiary content, the 117 gram Pzbr containing a capsule with 3.6 grams of phopshorous. The low velocity (under 600 m/sec) MG-FFM, usually derided for its lack of penetration, was actually quite satisfactory when loaded with one of the various Pzgr projectiles which seem to have become available from 1941. Maximum penetration (100 m/90 degrees) varied between 18 and 24 mm depending on type, with the more realistic 300m/60 degree giving figures of 9-10 mm. The effect of prior penetration of the usual angled 3mm dural skin varied hugely, from about 5 percent to around 40 percent reduction, depending on the projectile type and the striking angle. As one would expect, the results for the higher velocity MG-151/20 firing the same projectiles was slightly better, at 12-13mm/300m/60 degrees. The British considered what thickness of armour was required to protect against this ammunition, and determined that for a bomber around 15-18mm would be adaquate, although for protecting the rear of the existing Spitfire and Tempest fighters the best solution within the weight limits would be two plates of 7mm and 4mm, 150mm apart.
The Allied 20mm Hispano was significantly more powerful than the MG-151/20, but little attempt seems to have been made to exploit this in terms of armour penetration. As already described, the RAF settled on a mixture of HEI and a SAPI projectile which was specified to penetrate 20mm/200 meters/90 degrees and ignite petrol in cans behind the plate. This was regarded, with some justification, as entirely adequate to deal with enemy aircraft. The US M75 AP shot for this cartridge was claimed to penetrate 18mm homogeneous plate or 16.5mm face-hardened armour at 457 meters/70 degrees. Another US official source gives penetration at 300m as follows: 31-39 mm/90 degrees (depending on the armour hardness), 19mm / 60 degrees and 10mm/30 degrees (presumably for average armour hardness). The Germans surprisingly credited this loading with only 25 mm/100m/90 degrees, although noted that passing through the usual dural skin only reduced this to 21mm. The British did experiment with a tungsten-cored type, similar to Hartkernmunition (the AP Mark III.z) designed by Janecek of 'squeezebore' gun fame, which was intended to penetrate up to 60 mm/200 m/70 degrees, but it seems that it was ballistically unsatisfactory and was not adopted.
The Soviet 20mm ShVak API, which like their 12.7mm had a hard steel core with the incendiary mixture in the tip of the jacket, preformed erratically in the german tests, achieving 24mm/100m/90 degrees, but only 7mm after passing through the dural skin. In the same test, the figures for the 23mm Vya (taken at 300m instead of 100m) were 30mm and 16mm respectively.
One curious aspect of AP performance is that the maximum damage to the aircraft to the aircraft structure was caused when the projectile had only just enough power to penetrate; higher velocities than this merely punched neater holes."
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Ammunition Belt Make-Up
"The pros and cons of the different types of projectiles were such that virtually all air forces loaded a mix of different types in each ammunition belt, although the exact make-up depended on the nationality, the gun and the circumstances, and varied over time. Unfortunately, comprehensive records do not seem to have survived, but in any case they would be of doubtful value because this was one choice which individual pilots or gunners often made for themselves (with or without official approval) as the ammunition belts were generally filled by ground crew at each station. What follows is therefore only indicative.
It should incidentally be noted that while disintegrating link steel belts were standard issue in the Second World War, some of the German ones could be changed between disintegrating and non-disintegrating modes as required. For a while in 1943 fabric belts were issued for some American .50 in Browning guns due to a production shortfall in metal belts (although there is some doubt about whether these were used in aircraft, which had priority for steel belts). Some guns (e.g. the US 37mm M4 and IJA 37mm Ho-203 and 57mm Ho-401) used 'closed-loop' belts which were built into the magazine and non-disintegrating.
The RAF fighters armed with eight .303 in guns differed from the usual practice by loading each gun with only one type of ammunition. During the Battle of Britain in 1940, the reported use was three guns loaded with ball, two with AP, two with Mk IV incendiary tracer (the incendiary material ignoted on firing and burned throughout the flight, giving a tracer effect) and one with Mk VI incendiary (the 'De Wilde'). It is not clear why the Mk VI was used so little or why ball was used at all, possibly there was a shortage of the more effective loadings.
RAF Bomber Command principally used .303 in guns for defensive fire. In 1942 the approved ratios for loading the belts in four-gun turrets were 65 percent AP, 25 percent incendiary and 10 percent tracer (two-gun turrets had 20 percent tracer with the others reduced accordingly.) Between 1942 and 1944 the approved sequence was 70 percent AP, 20 percent incendiary and 10 percent tracer. This was modified in May 1944 to increase the proportion of incendiary to 20-30 percent, and changed again just before the end of the war to 100 percent incendiary, on the grounds that the German fighters were too heavily armoured for rifle-calibre AP to have any effect, whereas incendiaries at least stood a chance of setting light to something. Fixed .303 in guns for air fighting were loaded 50 percent AP and 50 percent Incendiary; for attacking ground targets the figures changed to 75 percent AP, 25 percent Incendiary. The .303 in Mosquito FB nose guns were loaded with unmixed belts of AP and incendiary rounds; i.e. two guns fired only AP, two only incendiaries (this also appeared to be standard practice with Spitfire .303s). The few .50 in Brownings used in Bomber Command (initially only in American-made aircraft) also saw changes in the loading sequence, from 40 percent AP, 40 percent Incendiary and 20 percent tracer in 1942, to 60 percent AP, 20 percent incendiary and 20 percent tracer in early 1944. Spitfires equipped with the .50 in used 50 percent each of AP and incendiary rounds until the M8 API became available, when that was used exclusively.
The Luftwaffe saw considerable variations in belt loading, as follows:
The 7.92mm MG-17 used in fighters were loaded with 50 percent AP, 40 percent API and 10 percent HEI (a Beobachtungsgeschoss, or observation round, which exploded on impact to show the pilot he was on target). For ground attack and for the MG-15 and MG-81 felxible guns, the sequence typically changed to equal proportions of AP, AP-T and API; v-munition loadings were only used in the MG-17. The 13mm MG-131 was loaded with one or two HEI for every AP/T. Official loadings for the 20mm belts and magazines varied at different times and places. Three types of projectiles were usually mixed in the belts: HEI (M-Geschoss), HE/T and AP/API or APHE. Ratios quoted include 1:1:1, 3:1:1, and 2:2:1 respectively.
Generally speaking, the more powerful weapons were able to provide sufficient destructive power with only one or two projectile types, so belts were less varied. As we have seen, an equal mix of HEI and SAPI became standard in the RAF's 20mm Hispanos, whereas the 30mm MK-108 principally relied on the M-Geschoss HEI it was designed for. The .50 in Browning fighter belts in US service started the war loaded with 40 percent AP, 40 percent Incendiary and 20 percent tracer. The tracer fell out of favour when it was realised that it was providing more help to the enemy. By the end of the war, fighters were primarily loaded with the M8 API (which appeared in service in spring 1944), as this proved to be a good general-purpose projectile, although the M23 incendiary also saw some use.
Some fighter pilots loaded the last section of their belts with tracer, to give them a warning that they were close to running out of ammunition (round counters not being commonly used, or at least looked at during combat). However, the enemy soon realised this and could turn it to their tactical advantage."
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Yeah, I understand that, but how did they detonate them? Electrical, blasting cap, etc.? TW probably knows.
From what I read they were exploded by electrical ignition.Atleast this was the case with the Blenhiem.
:salute
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Then please explain the spherical blast patterns of the British static tests posted in this thread?
Your going to have to post the one you mean.
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If you place that round in sealed 50gal drum hanging staticly in the center and detonate it, the drum will act similar in response to the belni's rear section because both are for intensive purposed sealed compartments. When it detonates on contact to the outside of say the sealed 50gal drum it will detonate out and forward with a contact fuse. If it is the version of the round to ignite fuel tanks with a dealyed explosion it will be the general explosion you are speaking about.
Here, this is an excellent reference.
http://rapiddigger.com/download/aviation-luftwaffe-ww2-ammunition-manual-1936-1945-german-pdf-9273588/
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The HE(M) shell had a time-delay fuse so it would detonate inside the wing/fuselage structure.