Shortround6
Major General
The Squash head round is a special projectile, it may have a DP use as a substitute HE round but normal HE ammo cannot act like Squash head ammunition against armor.
MK108 impact on ground targets?
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The Squash head round is a special projectile, it may have a DP use as a substitute HE round but normal HE ammo cannot act like Squash head ammunition against armor.
- Thread starter
- #22
wiking85
Staff Sergeant
How about the impact on unarmored or lightly armored targets, like halftracks?
Kryten
Senior Airman
That would make a right mess if you dropped a couple in the top of a half track! 20mm firing ap-he at a far higher rate and velocity would be a more effective weapon though, 4 x MG151's for instance!
The problem with the 30mm is it has a trajectory like a rainbow, that makes range estimation far more critical, higher velocity rounds flying flatter would score more hits!
The problem with the 30mm is it has a trajectory like a rainbow, that makes range estimation far more critical, higher velocity rounds flying flatter would score more hits!
- Thread starter
- #24
wiking85
Staff Sergeant
Would it in terms of destructive HE effect over twin 30mms?
Kryten
Senior Airman
He frag would be effective against infantry, but anything armoured, even lightly and you have a problem, little he rounds are not effective against armour, and the chances of a hit are lower with these weapons, and it's hard enough as it is!
- Thread starter
- #26
wiking85
Staff Sergeant
Well, looking at the HE contents the Mg151/20 had 18.6g HE and the 30mm Mk108 had 72g HE. As 20mm rounds could rip open a half track the much greater explosive content would destroy it.
IDEAL WW2 FIGHTER ARMAMENT
- Thread starter
- #27
wiking85
Staff Sergeant
The Mk108 rounds had 72 grams per round of HE. Several hits of that on engine deck armor should have an effect.
Some rounds had 85 grams:
Komet weapons: MK 108 cannon
https://en.wikipedia.org/wiki/Pentaerythritol_tetranitrate
with this explosive
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Kryten
Senior Airman
I think you grossly overate the effect small amounts of HE has on armour, the whole point of armour is to prevent penetration by blast and fragments, and the whole point of AP rounds is to defeat armour plate.
They fired AP at armoured vehicles for a very good reason, as I mentioned above, I witnessed 30mm RARDEN fire hitting the side of an Fv432 and the sum total of the damage was a few scoops in the surface, the side of an Fv432 is less than half an inch thick, which was considered sufficient to stop small arms, HMG and shell fragments up to 122mm calibre, and a RARDEN has a much higher muzzle velocity than a Mk108!
72 grammes is not a lot of explosive, it's not going to worry an armoured vehicle much unless you get lucky as cause a fire!
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- Thread starter
- #29
wiking85
Staff Sergeant
72-85 grams of the most powerful explosive possible concentrated again a weak spot of armor in a round designed to cause not just armor penetration, but widespread structural failure in an aircraft. The whole point is to not use kinetic energy to breech armor, its using chemical energy to achieve armor breech:
View: https://www.youtube.com/watch?v=ZoLLDi-M3fk
Kryten
Senior Airman
I had a funny feeling that film would crop up!
Your comparing a thin aluminium wing skin, hollow inside the structure and no protective plate to an armoured vehicle designed to keep blast and fragments out, it's not remotely comparable!
Your arguing blowing up a bean tin is the same as punching through an anvil!
PETN is not the most explosive substance either, it's just one of a family of fillers!
Your comparing a thin aluminium wing skin, hollow inside the structure and no protective plate to an armoured vehicle designed to keep blast and fragments out, it's not remotely comparable!
Your arguing blowing up a bean tin is the same as punching through an anvil!
PETN is not the most explosive substance either, it's just one of a family of fillers!
- Thread starter
- #31
wiking85
Staff Sergeant
Its also the tracer version of the HE round, not the most explosive of rounds. I take your point, but against 15-20mm of armor 85 grams of concentrated aimed/focused Hexagon (not a grenade layout where it disperses the blast effect) should be enough to breech it. The issue you are right about is getting hits with 2 vs. 4 guns, lower velocity, and lower rate of fire.
Kryten
Senior Airman
15mm-20mm of armour would only be breached by a shaped charge of that size, blast is a weird force, it always follows the easiest path unless you aim it, if they had developed a 30mm AP round there's no doubt that would be capable if disabling armoured vehicles, but plain old HE simply won't cut it.
- Thread starter
- #33
wiking85
Staff Sergeant
What are you basing that on?
Shortround6
Major General
What "aimed/focused" effect are you talking about? The German mine shell was no more aimed/focused than a Hand grenade was.
The idea behind the German bundle charge was that ALL the grenade heads would go off at the same time ( or darn close) creating one big blast, not 2-10 little blasts spread out over time and distance. When dealing with explosives timing can be critical. PETN "burns" at 7-8,000 meters per second. TNT "burns" at 5,800m/s. A 1/2 dozen cannon shell hits, even in one second, are still 6 little distinct explosions and in no way comparable to the same amount of explosive going off "all at once".
You can use Chemical energy to breech armor, you just need to use specialized shells/projectiles and not general purpose or simple high capacity HE rounds. Of course these specialized shells/projectiles don't work as well against non-armor targets.
As far as using shaped charge projectiles from the MK 108 goes, Kyten has made a pretty good guess. Shaped charge penetration was advancing quite a bit during WW II so early performance was quickly improved but that advancement continued for quite a while after the war if not right up to today. What modern 30mm rounds can do bears no relation to what WW II rounds would do. Early (1940) shaped charges would not even penetrate a thickness of armor equal to their own diameter (and that is for an unspun projectile, spinning the projectile seriously degraded performance) while penetrations of 4 times the diameter were achieved in the 1950s in service ammunition and some rounds/war heads were heading for 7 diameters by 1960. Again, unspun. The spinning was such a problem that the French AMX 30 tank used a special double wall shell in it's 105mm cannon. The inner shell held the shaped charge and was separated from the outer shell by ball bearings, The outer shell revolved at high speed, the inner war head revolved much slower. The smaller diameter war head was traded off against the slower spin.
- Thread starter
- #35
wiking85
Staff Sergeant
Can you demonstrate that 75 grams of Hexagon explosive couldn't penetrate 15-20mm of armor?
Shortround6
Major General
Can you demonstrate it can? and 15-20mm is a 33% increase in thickness.
MK 108 mineshells have nose fuses. Shell will detonate after a very short delay ( for use against aircraft you want the fuse to initiate on the skin but detonate after several feet of travel so it explodes inside the aircraft instead of as it goes through the skin) not so good for armor penetration as shell may be splitting open when it detonates. Or instantaneous fuse detonates the explosive while it is pretty much still in the form of a cylinder that is end on to the armor (or angled) but then most of the blast goes sideways along the face of the armor.
The 75 grams of Hexagon explosive will penetrate 20mm of armor if was arranged in a shaped charge and detonated at the right distance. in fact you need much less.
27 grams of HE but then you don't get the blast effect against aircraft. See: http://www.ordnance.com/images/30mmHEDP1/30mmHEDP1 (4).JPG
And look at chart on the right hand side. The PEI-T round is not very effective against "heavy" armor but is more effective against everything else than the HEDP round.
If HE shells alone would blow holes in moderately thick armor then people sure wasted a lot of time and effort designing/building AT rounds for a variety of cannon.
Early HE ammo had 570 grams of explosive and later versions had 670 grams yet they designed and issued two different hollow charge rounds for this gun. The first would penetrate 45mm of armor at a 30 degree impact angle. (30 degrees from perpendicular).
The 2nd of four different Hollow charge projectiles for the German 10.5cm howitzer used 2.12kg of cyclonite/TNT/Wax to penetrate 100mm at normal impact or 70mm at 30 degrees. The 3rd design penetrated about the same but used less explosive.
An awful lot depends on the arrangement of the explosive, the liner shape and material and the the fuse.
kool kitty89
Senior Master Sergeant
Were there any attempts at shaped charge 30 mm mine shell developments during the war?
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Keep in mind that not all Mk108 shells were minengeschoss (M-shell), there was also the hydro-dynamic fused incendiary shell, too.
Shortround6
Major General
There were a few other types too. However at the time (WW II) a shaped charge 30mm shell was pretty much a waste of time. State of the art for shaped charges from rifled guns for service ammo in WW II was a penetration of about 1 diameter of the cone or just a bit better. Complicating this was that you need to detonate the charge at an appropriate distance. Too close and performance/penetration suffers. Many guns firing shaped charges did so at reduced velocities to limit the impact velocity and give the jet time to form/work with the stand off that the hollow nose cone provided. US 105 howitzer for example fired the HEAT projectile at 1250fpm instead of the 1550fpm the gun was capable of with full charge HE ammo. German Pak 75 could fire a Heat round at 450m/s compared to around 550M/S for HE and 790m/s for AP, both of which were heavier than the HEAT shell. Please note that they were trading the ability to hit (higher velocity means flatter trajectory and less lead on a moving target) for better penetration.
Shaped charge ammo also needs a fair amount of over penetration in order to achieve a good level of "lethalality".
tank killing can be crudely expressed by the formula PK=PH x PP X PL or Probabilty of Kill = Probabilty of Hit X Probabilty of Penetration X Probabilty of Lethal damage.
Penetration by 75-105mm shot automatically gives a high PL due to the size, weight and speed of the "stuff" flying through the tank interior. Smaller AP rounds can have diminishing results. 7.9-14.5mm AT rifles can require multiple hits/penetrations in order to cause enough damage/casualties inside the tank to "kill" it. Shaped charges need a big enough "jet" to get through the armor to cause damage/casualties behind the armor.
A picture showing a few variations.
Shaped charge ammo also needs a fair amount of over penetration in order to achieve a good level of "lethalality".
tank killing can be crudely expressed by the formula PK=PH x PP X PL or Probabilty of Kill = Probabilty of Hit X Probabilty of Penetration X Probabilty of Lethal damage.
Penetration by 75-105mm shot automatically gives a high PL due to the size, weight and speed of the "stuff" flying through the tank interior. Smaller AP rounds can have diminishing results. 7.9-14.5mm AT rifles can require multiple hits/penetrations in order to cause enough damage/casualties inside the tank to "kill" it. Shaped charges need a big enough "jet" to get through the armor to cause damage/casualties behind the armor.
A picture showing a few variations.
