Mr. Tittles

Ive given it some thought and have come to the conclusion that blast values, at least for mortars, should reflect the varying degrees of deadliness of these weapons. Its more an Apples to Apples thing. Mortars generally land a shell in a perpendicular fashion. This is because the fins align the shell. Since most mortars are smooth bore and have no shell spin, they are basically bombs with varying wall thickness/different materials and HE fillers. the game probably approximates the deadliness of shells as circular and this corresponds to mortars also. Heres a comparison of German (G) and Soviet (S) 120mm S:125 G:119 82mm/81mm S:26 G:26 50mm S:5 G:6 The blast values must come from somewhere. What is the formula? [ November 07, 2003, 07:25 PM: Message edited by: Mr. Tittles ]

Yes, my monkey was in need of refreshing, thank you.

It would seem a smoothbore weapon would naturally have a different pressure vs shell position in the tube than a rifled weapon. In a rifled weapon, there is a spikey surge in pressure when the band bites into the rifling. the projectile must be accelerated both translationally and rotationally. When the rifled weapon fires, the band makes a pretty good seal. I wonder how sealing is accomplished in a smoothbore high velocity weapon?

Thats a good question. If the game doesn't,then airbursts are even more deadly.

Heres a hypothetical example. A tank gun fires a HE shell. It is travelling at 2500 fps. It hits a tree branch in an outer tree of a woods and detonates on superquick mode. The detonation of the HE train within the shell is probably a millisecond or so. Still, this allows the shell to travel about 2.5 feet! I often wonder about these claims of airbursts and how quick it needs to be. Anyway, the shell explodes and fractures into fragments of varying sizes. The front and rear parts usually forming large scabs and the sides 'balloon' out forming a collection of different sized objects. The front piece would have an additive velocity vector. Its velocity would be the sum of the forward motion of the shell, and the additional kick it got from the explosion of the HE. Since larger fragments may get less HE kick (just like a gun trying to fire a larger bullet gives it less velocity), this would have to be taken into account. The rear piece, typically being thicker, would get a double penalty. Its forward motion would fight the HE kick. Its large and big and trying to go backwards after being thrown forward. The sides of the shell are even still more interesting. They not only get a forward velocity and a HE kick velocity but an additional rotational velocity from the spinning of the shell. This rotational velocity to translational velocity component can be somewhat helpful, especially for the larger chunks. An interesting thing is that the rotational component is independant of fragment size (as long as the fragments are coming from the sides). Lets take the case of a shell spinning at 20,000 rpm. Its a 105mm howitzer round (4.134"). The calcs give 360 fps JUST from the rotational velocity being converted to translational energy. The larger the round, the greater this component for a given rotational velocity. For the larger chunks of metal, this could be a significant boost. Also, for shells like bursting smoke shells (of any type), this makes for deadly projectiles. Note that mortars that are smooth bore do not get this velocity component. A 105mm shell weighing 33 lbs loaded has something like 28 pounds of metal. Lets take the case of a 105mm bursting smoke round that is coming in at 45 degrees and detonates up in the trees. For the sake of argument, lets assume its coming in at 500 fps. lets further assume that the bursting charge ONLY cracks open the shell and gives little to no kick velocity to these fragments. The result would be a 'rain' of large fragments with a conical shape travelling at 616 fps. These would be long slivers of metal with some weight to them. The front of the shell would just have the 500 fps! What about the back? well, in this case, it would travel forward at 500 fps also! In any case, theres 28 lbs of fragments flying with deadly velocity. But in reality, even a bursting smoke shell WOULD give SOME HE kick. The reason for this is that its design is relying on the HE to ignite/spread the smoke chemical. If its a point detonating ground burst, then the chemical would be shot into the ground if it is not dispersed quick enough. The bursting charge would need the strength (brisance) to not only crack open the shell itself but also eject the chemicals outward. My gut feeling about the relationship between shell wall thickness/material and bursting charge and effectiveness of HE shells (or any bursting shell) is that it is only part of the equation. Angle of descent, forward velocity, height of detonation, etc are all major players. Hopefully, the artillery model and direct fire model can reflect these realities. [ November 07, 2003, 10:22 AM: Message edited by: Mr. Tittles ]

Ive read that they use a plug to overstretch the barrel. They force a plug down a less than 105mm barrel and stretch it out from the inside till it becomes 105mm. This gives it incredible strength.

While jasonC has been roundly spanked in this thread, I will put my neck out and declare the following: The game probably does not take into account shell velocity, angle of descent and possible fuze effects. I often wonder about fragment velocitys (well.. every now and then), and the relationship between other fragment forces. The fragments from a HE projectile/bomb typically are directed to the sides of the shell. The shell usually was travelling in a forward motion before being blasted to bits. The forward motion and the sideways motion would have a vectoring effect. If the velocity of the shell is substantial enough, and the fragment HE driven velocity is slow enough, then this has considerable effect on the target end. In the case of low angle descent, it could possibly be beneficial!

Bombs had another important advantage over artillery. A shell fired through an artillery barrel is subjected to tremendous heat and stress. And an artillery piece must be able to fire thousands of rounds without mishap. Consequently an artillery round requires a heavy casing, which lowers the amount of weight of the shell given to explosive power. This is not a problem if one wishes to pepper an area with shell fragments. However, the greater the amount of explosive, the greater the amount of shock created by the explosion. A bomb designer worked within different limits. A bomb left the aircraft with very little stress or friction. Consequently if the so designer wished it was possible to devise bombs that carried very little casing and a large amount of explosive. The result was a shock wave that often created its own fragmentation by destroying buildings, trees, and anything else in its path. The standard 500-pound GP bomb carried about half its weight in pure TNT. Some bombs had lighter casings and a higher percentage of explosive to maximize blast. Fragmentation bombs had heavier casings that were designed to break apart. Later bombs used more complex explosives like amatol, which increased blast by 25 percent. Crews in the South Pacific took whatever they could get. Because bombs were dropped from a passive position, they could be designed to kill men and damage targets in three ways. One was shock. Because the amount and type of destruction varied, choosing the right weapon for the mission was difficult. However, shock effect, for our purposes, is probably best measured by the ability of the bomb to cause damage at a certain distance. The damage itself was done by a tissue of air propelled by the explosion; it had tremendous pressure initially but dissipated rapidly. According to U.S. Army figures, an enemy in the open would suffer a ruptured eardrum from a 100-pound bomb dropping within a radius of thirty feet. If a 500-pound bomb was dropped the radius increased to forty to fifty-five feet. A 1,000-pound bomb would rupture an eardrum within an eighty- to ninety-foot radius. Killing was a different matter. A 100-pound bomb would kill 50 percent of men in the open at a radius of ten feet. A 500-pound projectile had the same effect at fifteen to eighteen feet. A 1,000-pound bomb would kill half the enemy within a radius of thirty feet. (Please note that these figures are based on radius, not diameter.) Obviously there was a law of diminishing returns here, familiar to any study of mortality and weaponry. Yet the exchange was all too clear. There were many solo bomber missions in the South Pacific, but for the most part the bombers came in units. All of these figures given for shock—and let us remember that a man with a broken eardrum was probably out of the campaign—were multiplied many times by the fact that so many bombs were dropped. Secondly, bombs killed with fragmentation. Fragments came from two different sources. One was from the casing of the bomb itself, usually a soft metal. The other was the debris blown into the air by the shock wave. Fragmentation bombs heavier than 100 pounds were almost always aimed at enemy infantry (whether attackers could see the enemy or not), aircraft on the ground, and antiaircraft installations. Officers knew that most of the men would be prepared for air attack at air bases and important positions in an infantry position. Therefore bombs were set to explode above the ground. The results were wicked and explain better than any anecdote why smart soldiers dug deep. If a 500-pound bomb exploded twenty or thirty feet above a small area, the chances for injuring a soldier who was in the open or a shallow foxhole (what the military called a 10-degree fortification) were 100 percent. A deep trench, particularly if made with angles, reduced the chances of casualties to less than 30 percent. No field fortification could prevent complete catastrophe if there was a direct hit, but digging a trench as deep as a man is tall made the victim far less vulnerable to air attack. Yet with enough bombs falling some men on the ground would die or suffer wounds—whether physical or psychological—regardless of precautions. If a bomb struck an enemy advancing to the attack above ground, the results could be catastrophic.

Characteristics of US Explosives. The table below lists the characteristics and principal uses of US explosives. Explosive Principal Uses Velocity of Detonation Relative Effectiveness as a Breaching Charge (TNT – 100) Intensity of Poisonous Fumes Water Resistance (m/sec) (ft/sec) Black powder Time blasting fuse 400 1,300 0.55 Dangerous Poor Ammonium nitrate Demolition charge (cratering) 2,700 8,900 0.42 Dangerous Poor Amatol 80/20 Bursting charge 4,900 16,000 1.17 Dangerous Poor Military dynamite, M1 Demolition charge (quarrying, stumping, and ditching) 6,100 20,000 0.92 Dangerous Fair Detonating cord Priming 6,100 to 7,300 20,000 to 24,000 Excellent TNT  Demolition charge (breaching)  Composition explosives 6,900 22,600 Dangerous Excellent Tetrytol 75/25 Demolition charge (breaching) 7,000 1.2 Dangerous Excellent Tetryl  Booster charge  Composition explosives 7,100 1.2 Dangerous Excellent Sheet explosive M118 and M186 Demolition charge (cutting) 7,300 2,400 1.14 Dangerous Excellent Pentolite 50/50  Booster charge  Bursting charge 7,450 24,400 Dangerous Excellent Nitroglycerine Commercial dynamites 7,700 25,200 1.5 Dangerous Good Bangalore torpedo, M1A2 Demolition charge (wire and minefield breaching) 7,800 25,600 1.17 Dangerous Excellent Shaped charges M2A3, M2A4, and M3A1 Demolition charge (cutting holes) 7,800 25,600 1.17 Dangerous Excellent Composition B Bursting charge 7,800 25,600 1.35 Dangerous Excellent Composition C4 and M112 Demolition charge (cut and breach) 8,040 26,400 1.34 Slight Excellent Composition A3  Booster charge  Bursting charge 8,100 26,500 Dangerous Good PETN  Detonating cord  Blasting caps  Demolition charges 8,300 27,200 1.66 Slight Excellent RDX  Blasting caps  Composition explosives 8,360 27,400 1.6 Dangerous Excellent This website claims 80/20 Amatol to be as 1.17 factor to TNT. UNITED STATES MARINE CORPS THE BASIC SCHOOL TRAINING COMMAND 24164 BELLEAU AVENUE QUANTICO, VIRGINIA 22134-5019

M48,75mm high-explosive shell,standard (for M3 and M4) :super normal,normal,or reduced charges —with 1.93 lbs.super charge,14,000 yds. range;with normal 1.05 lbs.charge,11,400 yds. range,and with 0.38 lbs.reduced charge,7200 yds. range;M4 propelling charge was 1.93 lbs.of super charge,range of 14,000 yds.;shell contained 1.47 lbs.of TNT (or 0.11 lbs.of cast TNT and 1.36 lbs.of Amatol as an alternate);propelling charge was 0.92 lbs.FNH powder (Drawing in 1944 Catalogue,p. 515) 81mm mortar Firing;mortars Range 13C Fins on shell stabilize it in flight;the fins also cause nose to strike first.A point-detonating impact type of fuze is fitted to the nose of the shell.The propelling charge attached to the base end of the projectile consists of an ignition cartridge and propellant increment.The increments of the charge are removable to provide for zone firing.Ammunition was an H.E.shell,M43A1 (6.87 lbs.)(range 100 to 3290 yds.);M36 (10.62 lbs.)(range 300 to 2558 yds.); and a chemical shell,M57,10.75 lbs.(range 300 to 2470 lbs.)(Photo of mortar in 1944 Catalogue,p. 152). M43 H.E.shell also used in 81mm mortar:range is 3,300 yds.(1944 AIG,p.280)(according to this manual,range of M43A1 is approximately the same as the M43) Shell,H.E.,M44 also used in 81mm (1944 AIG,p. 285) M43A1 —81mm,H.E.shell,6.92 lbs.,TNT bursting charge of 1.22 lbs.or 0.98 pound of 50/50 Amatol and 0.19 pound cast TNT,or 1.28 pounds trimonite (Drawing in 1944 Catalogue,p.529). Here is data for the US 75mm M48 and US 81mm mortar rounds. They refer to 1944. Notice the Amatol AND TNT mix in the shells. Trimonite also used in 81mm. Trimonite High explosive used as a substitute for trinitrotoluene as a bursting charge. Trimonite is a mixture of picric acid and mononitronaphthalene. Trinitrophenol Picric Acid. Trinitrotoluene (TNT) High explosive widely used as explosive filler in projectiles and by engineers; trinitrotoluol. [ November 05, 2003, 05:35 PM: Message edited by: Mr. Tittles ]

The howitzer was probably firing supercharge at a low angle and the shell was coming strait at the group of officers. You absolutely sure it was not supersonic? Hearing shells whistle before impact depends on where they impact. If they fly over you, you will hear them. If they are to your sides, likewise, you will hear them. When they come strait at you, they better be moving mighty slow if you are to hear them. The basic advantage is when a ranging round falls beyond a lethal distance from a unit. They can elect to quickly move away or to dive into/under cover. Mortars are notorious for giving little warning. High velocity guns are nicknamed crash-booms because the explosion preceded the report of the firing weapon.

http://users.skynet.be/jeeper/page57.html

I believe every nation went to some amatol mixture as the war progrossed. The sherman 75mm may have started out with all TNT but went to a mixture of TNT and some amatol also. It was just too good a way to extend explosives for a small setback in bang probably.

I will have to dig it up but I remember two studies that showed that men in trenches, with light overhead cover/small dugouts into the walls of trenches are fairly well protected against 81mm/60mm mortar fire. The main danger is 81mm delay fuze mortar fire which can necessitate a hefty roof. The steep angle of descent and lack of ricochet burys the HE and makes it much more effective. Even larger weapons, 120mm mortar and 105mm arty need fairly close hits to defeat a defensive system like this. Proofing against these direct hits from these weapons requires major construction.

Heres an interesting passage from a German FO... (13) On October 13, the Canadians were pounding us in preparations for their attack. Our observation house (10) was shot into rubble, leaving only the chimney. However, we stuck it out in the cellar. At dusk it was my turn to go up on watch. With a field telephone and binoculars, I climbed up the chimney and saw what seemed to be several officers looking over this bunker with binoculars and having maps before them. I called (whispered) for a single high velocity artillery round. (A straight shot that gives nobody time to duck). It was right on target and I saw a steel helmet flying like a Frisbee. A few minutes later a van came and men ran towards the bunker. It was getting dark and I couldn’t tell who they were, but I assumed they were medics and thus I refrained from further shelling of the area. - In the book 'Semper Paratus, The History of the Royal Hamilton Light Infantry', page 278, the author writes "On Friday the 13th, the Black Watch of the 5th Brigade went in, east of Woensdrecht, against the center of the isthmus. Joe Pigott watching through his binoculars from the RHLI positions near Hoogerheide, saw them cut to pieces by machine-gun fire (all four of their company commanders were killed) and their attack, too, failed." - I believe that my one 105-mm howitzer round killed these four officers. Notice that the velocity of the 105mm shell, giving no warning, led to its effectiveness This is similar to direct fire from many weapons. http://members.shaw.ca/calgaryhighlanders/knolle.htm [ November 05, 2003, 12:52 PM: Message edited by: Mr. Tittles ]

Would the following be true? 1. As shells get bigger, they rely upon HE blast more than fragmentation to have a target effect? 2. As HE blast increases, fragmentation size decreases? Smaller fragmenst scrub velocity quickly? 3. HE blast falls off quickly, like an inverse cube? 4. Fragmentation falls off like an inverse square? 5. Shells made of harder material can be made thinner?

American shell Total wt (lbs) Filling (lbs) Equiv wt (lbs) 75mm M3 shell HE M48 14.6 1.7 25 76mm shell HE M4281 12.9 0.9 20 If I read this correctly, the sherman 75mm is about the same as a 25 #r? The much maligned 76mm sherman shell is about 4/5 of a 25#r? Both shells have roughly the same unfilled weight? the 76mm would have to be smaller in length but thicker in shell casing? [ November 05, 2003, 10:15 AM: Message edited by: Mr. Tittles ]

The artillery modeling in CM is pretty simple. I can't imagine that the end effects of artillery is ground breaking either. Casualty effects of guns can be traced to angle of descent, velocity, shell casing thickness, HE payload, distribution errors of aiming. Further factors are fuzing, ricochet, etc. Direct fire, with high velocity weapons, reduces errors but has its own uniqueness. [ November 12, 2003, 12:09 AM: Message edited by: Mr. Tittles ]

The one difference of note, which isn't really a change to the Arty model per se, is that arty barrages (and in fact any HE explosions) will kick up a fair amount of dust under the right conditions. The result is that under an HE barrage can have the same effects as a smoke screen in addition to the casualty/supression effects. Cheers, YD </font>

Heavy machine gun fire from enemy strongpoints, which consisted of mutually supporting, dug-in, logged emplacements, manned by eight to ten men, continued to impede the advance southeast of Vossenack. Mortar fire fell almost continually in this area, and small quantities of white phosphorus artillery were used by the enemy. Southeast of Kleinhau, satisfactory progress was made by the 1st Battalion, 13th Infantry. Farther south, in the 121st Infantry sector, the 2nd Battalion was still unable to advance. Note: I have come across sporadic reports that the Germans did use WP infrequently.

Why isn't there white phosphorus in CM? "WP was, so far as our research shows, rare on the battlefield. Very few weapons could fire it, so right there we question if we should bother with it in the first place. And when used HE or Smoke could have done just a good of a job at CM's level." -Steve

Half of the men who survived the river crossing lost their rifles and helmets. All mortars and three of the four machine gun sections were also lost. Grenades were redistributed and rifles were taken from the German prisoners. Major Regan lead his men south of Niederau to a road fork at the edge of a patch of woods. The men of Companies K and L went all the way preceded by a rolling barrage of white phosphorus artillery shells, reaching the edge of the woods at 0430. Here they waited for Company I to join them.

6. When tanks are advancing, they must use their guns for what is known as reconnaissance by fire; that is, they must shoot at any terrestrial objective behind which an anti-tank gun might be concealed and take these targets under fire at a range greater than that at which an anti-tank gun is effective; in other words, at a range greater than 2,000 yards. They should fire at these targets with high explosive or with white phosphorus, because if the enemy receives such fire, he will consider himself discovered and reply at a range so great as to render him ineffective. 7. When tanks are passing or approaching hedges or walls, they should comb them with machine guns so as to remove the danger from close defense anti-tank grenades and sticky bombs. 8. When tanks use smoke or white phosphorus against infantry, tanks, or anti-tank guns, they should continue to fire into the smoke with high explosive or with machine guns if they are within range in order to prevent enemy movement. 13. Tanks should remember that anti-tank guns are not armored and are therefore susceptible to effective results from high explosive and white phosphorus. If, therefore, they are unable to get their artillery up to remove the anti-tank guns, they should engage these guns with high explosive at a range in excess of 2,500 yards and from defilade, or if they have good observation, by indirect fire methods, because under these circumstances the high explosive will get the guns, and the guns will not have lethal effect against the tanks. 14. When tanks are taken under surprise fire by anti-tank guns or by other tanks, they should immediately fire several rounds of white phosphorus short of the target and then maneuver to get a telling shot when the smoke clears, or when the enemy emerges from it. 15. In tank versus tank duels, the first round should be armor piercing. If this fails, the second round must be white phosphorus and short so as to give our tank a chance to maneuver, because by keeping it's gun laid on the smoke, it has a better chance of getting in the second telling shot than has the enemy, who when he emerges from the smoke does not know the location of our vehicle. g. Tank attacks can be stopped by artillery concentrations of white phosphorus and high explosives. Patton 3 April 1944 SUBJECT: Letter of Instruction No. 2 TO: Corps, Division, and Separate Unit Commanders [ November 03, 2003, 12:52 PM: Message edited by: Mr. Tittles ]

A little later on we heard the steel treads of a German tank coming down the road. As it got closer we could see it was one of Germany's largest tanks – a Tiger Royal. As it got close to the roadblock, our 57MM opened up on it. It was like shooting peas at it – those shells just bounced right off of it. It continued to rumble toward us. When it got alongside where I was dug in, I fired my bazooka at it. I hit the tank on its turret and that shell didn't penetrate it either. I think it just made them mad. The tank stopped and began to rotate its 88MM gun toward me. Fortunately, I had cut the wire of a barb wire fence behind me, so I left the area. The tank fire a couple of shells in my direction and then moved forward. As it approached the "T" intersection, our Sherman tanks with the 75MM guns opened up on the Tiger – their shells didn't fare much better than my bazooka or the 57MM shells. The 75's bounced off the tank. The Tiger opened up on our Shermans and knocked them both out. In fact, one of the 88s went in one side of a Sherman and out of the other side. When the Tiger got up to the "T" intersection it was too large to fit around the corner and as it was trying to maneuver around, we called in our artillery from our 105MM self propelled guns and their shelling with white phosphorus set the German tank on fire. As the German tankers bailed out, we captured them. The bitter cold weather stayed with us – cold and snow, so no air cover. As we moved down the roads or fields attacking the Germans, we would stay by the rear of a tank and get a little heat from the exhaust pipe. The only bad feature of that, however, was the Germans would zero in on the tanks with anti-tank artillery and machineguns. Our light tanks were equipped with a short barrel 75MM and machine guns, so they were no match for armor. They were used against infantry and ground troops. The Shermans were a match for the German Mark Series tanks but not the Tigers. In one sector we surrounded a large number of German troops. They were mainly Wehrmacht (draftees) but they had "SS" officers commanding them, so they didn't give up until they were almost demolished.

I saw another figure by a doorway. I called out to him. "What outfit is in this town?" He yelled "Americaners – Americaners" and he ran down the street. We got out of the town and radioed back for artillery. Our 105MM showered the town with white phosphorus shells and set most of the buildings on fire. We then attacked with the help of our tanks which had pulled up behind us. After we took the town, the German artillery battered us very heavily.