Hooligan posted 06-16-99 03:43 PM            

I just sent this to IMOL.

I am writing this to explain why I think the gun effectiveness in the WB 2.7 beta is significantly off.

I ran some offline tests to check gun lethality. The tests consisted of 2 parts.

Part #1 shoot down some 109s and P-51s (only) in the "Air Attack" scenario. All shots were performed at convergence using only the HS 2x20mm on a spit IX or the 6x.50 Cal on an F6F or P-51. I shot down 9 planes with the Spitfire and 8 planes with the .50 cal armed aircraft. Further bncu ran very similar tests and posted the following on AGW:

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As part of my testing for 2.7 beta I ran tests (offline, but later cross-checked firing at online volunteers) with every weapon WB models.

Not being satisfied with "feel" I ran 24 to 30 tests on each weapon, firing at 200-300 yards with convergence at 250, against fighters only (lethality against bombers is very dependent on your precision of aim). There's still a wide variability (standard deviation) in my results due to the variety of fighters I shot at, my own variability, and other factors, but this is mediated somewhat by the number of tests. In any case I listed, and will list here, the standard deviation I obtained.

The results here are hits/kill. Remember that drones don't (didn't) auger in when they lose important parts like engines or stabilizers, so a "kill" here is a full explosion.

Only some weapons are listed here but this should give you an idea of what's up:

UK Hispano 20mm: 5.00 ave, 2.86 std

GE MG-FF 20mm: 5.33 ave, 2.48 std

IJ type 99-1 20mm: 6.33 ave, 3.47 std

IJ Ho5 20mm: 6.63 ave, 3.69 std

SV ShVAK 20mm: 6.83 ave, 4.07 std

IJ type 99-2 20mm: 7.08 ave, 3.24 std

GE MG131 13mm: 22.36 ave, 10.96 std

SV UBS 12.7mm: 23.75 ave, 12.04 std

US Browning .50: 27.17 ave, 16.81 std

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My first online session in the beta yielded 257 hits and 9 kills from .50 cal guns, which computes to 57 real rounds per kill.

All this data is consistent and seems to indicate that the number of real rounds (i.e. 2 times the number of WB rounds) to kill a single engine fighter was 10-15 20mm rounds or 50-60 .50 Cal rounds.

Part #2 The shed test: I have run the full version of this test on every version of WB since version 2.0. Full results for 2.6 are posted at http://bmof-design.com/hooligan.htm. This sight also gives a detailed explanation of the test methodology. Suffice to say that the test consists of shooting the shed at F1 from point blank range with the different weapon sets to determine how many rounds it requires to destroy it. From this and the ROF (Rate Of Fire) information a relative lethality of each gun, and thus of each aircraft can be calculated. I ran shed tests on 4 guns. It takes the following number of real rounds to kill the shed.

.50 Cal = 575 (note: no change from 2.6)

Hispano Suiza 20mm = 132

MG151/20mm = 154

IJA Ho-5 20mm = 188

The shed tests indicate that while a single good 20mm (i.e. not the early war Oerlikon models) was worth 2-3 .50 cal guns in version 2.6, they are now worth 3-4 .50 cal guns. The "Air Attack" tests confirm the shed test results.

IMO the lethality of the weapons in WB 2.7 is significantly off. First, on average it should take significantly less than 50-60 .50 cal rounds to kill a single engine fighter. I think that the relative lethality advantage of cannon vs. heavy machine guns against single engine fighters is too large. Please consider the following evidence. Note that I have annotated my sources.

For simplicity's sake in the following discussions I am generally concentrating on the U.S. .50 cal round. The armor piercing capabilities of other heavy machine gun rounds should generally be similar and the penetration of 20mm rounds at practical ranges should in almost all cases exceed those of the .50 cal rounds.

The standard WWII .50 cal AP/I round (M8 Armor Piercing/Incendiary) "can ensure a 80 to 90 percent expectation of complete penetration against 0.8in (21mm) thick armour plate at 298ft (91m)." (1)

So what does this mean? Well the source does not specify impact angle or armor quality and or type (face-hardened or homogenous). We can probably assume that the armor in question was contemporary to the round (i.e. 1943 production). The 80-90 percent expectation or complete penetration indicates to me that this means the round will be very likely to penetrate from a range of angles. Maximum penetration for a clean 90 degree hit would obviously be more. This is for a stationary shooter and target. Depending upon the geometry of an air to air engagement the impact speed of the projectile might be significantly greater or lesser than in the static case giving it potentially much more penetration.

In non-Japanese fighter aircraft, the pilot, ammunition, oil and fuel tanks are generally protected with armor or self-sealing apparatus. For example: the pilot armor (both forward and rear) on a P-47D is 3/8" (9.5mm) thick (2). In a FW-190A8 the pilot head armor is 12mm thick and his back armor is 5 mm thick (3). The armor on these aircraft will protect the intended areas from .50 AP/I hits from some angles and in some cases. Clearly there are also cases when the round will penetrate to the critical area, work as intended and critically wound the aircraft or kill it outright. I haven't ever seen any book claim that the armor in WWII fighters was proof to anything above .30 cal guns. At practical firing ranges .50 cal guns can penetrate up to TWICE the thickness of armor typically found on one of these fighters.

The aircraft structure, radio equipment etc.. are much less resistant to penetration than the face-hardened pilot armor. For example: A 7.9mm German mg round can penetrate 850mm (that's correct 850!) of pine at 100m as opposed to only 5mm of steel at 100m (4). Face-hardened armor is much more resistant to penetration than aluminum aircraft structure, etc.. A round somewhat more similar to the US .50 cal was the 14.5mm anti tank round (4). It was somewhat heavier and faster (63.4g,1000m/sec) "It penetrated 40mm of armor at 100m; 35mm at 300m; 30mm at 500m; an AT rifle with this ammunition could still penetrate a light AFV's armor of 15mm at ranges of 1.5km, if the gunner was able to hit a lightly armored target at that distance."(4) Aircraft components like the skin, radios etcare unlikely to significantly slow an AP projectile although it might divert it or cause the incendiary or explosive to detonate before the optimal time. At any practical range, .50 AP/I and larger rounds have plenty of penetration capacity required to penetrate to any critical component of a typical fighter aircraft.

Aircraft can be generally be killed in 2 fashions. #1 Structural Failure. #2 The magic bullet. #1 kills would be blowing off stabilizers, wings etc Item #2 would cover any hit in the following areas with the requirements that the hit penetrates to a "critical component" and has sufficient killing effect against the target in question. Against many of these targets the "killing effect" would be incendiary (primary incendiary for an AP/I or explosive round), or secondary incendiary for a tracer or AP round). .50 cal US guns in the early war fighters were typically belted with 1 tracer followed by 2 AP and 1 incendiary. In the later years (1943+) the tracer rounds were replaced by tracer/incendiary rounds and the AP rounds were largely replace by AP/I rounds so that almost all rounds had primary incendiary capability (see the attached photo of an AP/I round penetrating a piece of armor plate). #2 kills would include hits on the pilot, fuel, engine, ammunition, coolant jacket, oxygen system, oil tank, control cables, hydrallic+oil+fuel piping. I just did a rough measurement of the presented target area of a spitfire from a cross-sectional drawing presented from the front quarter ((3) pg. 284). The major structural components take up approximately this much of the presented area:

Forward fuselage: 19%

Cockpit: 9%

Read fuselage: 21%

Wings: 44%

Tail: 7%

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Total: 100%

The "critical targets" take up approximately this much of the presented area:

Engine/glycol/coolant jacket: 9%

Oil Tank: 1%

Pilot: 4%

Fuel: 7%

Oxygen tanks: 1%

Ammo boxes: 4%

Fuel pipes, cables etc.. : 1%

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Total: 27%

From the dead 6 the critical components should take up a larger percentage of the cross section since the biggest parts of the aircraft (wings and fuselage) are presenting their smallest cross-section while many of the critical components are not presenting small cross-sections. Approximately 1 out of every 4 hits should typically be in a critical area. Some hits of course will deflect, fail to fuse, fail to have the desired effect on the critical component etc Also some critical targets may be non-critical at the time of being damaged; an empty fuel tank or ammo box for example. Still, with an average of 1 in 4 hits impacting a critical component, it seems that a typical single engine aircraft is very unlikely to survive 15-20 .50 cal hits. With this many hits, one of them is going to cripple the aircraft except in rare cases. Effects for 20mm AP, APHE and AP/I should be more fatal. These rounds have even more excess penetration capability and are less likely to be deflected. Further if the fusing works properly, the explosion at the point of the critical component should almost invariably prove fatal. In WB 2.7 the impact of 5-10 20mm on a single engine fighter is almost invariably crippling and 10-15 20mm rounds will result in an immediate kill. These results seem consistent with the large percentage of critical targets areas in a single engine fighter and the destructive capability of a 20mm round, and IMO a very welcome improvement to the lethality model.

The evidence that I have read indicates that critical hit kills (fires, explosions, pilot kills etc..) were the primary cause of kills on fighters. I have not found this to be the case in WB where stabilizer/wing/fuselage kills play a large part. Although their damage model is better than anything else I have experienced I believe that "critical areas and penetration effects" are very poorly represented. With weapon lethality based on kinetic and explosive energy and penetration effects ignored, cannons are given a large lethality advantage against single-engine fighters that I do not believe that they should enjoy.

Compared to APHE and AP/I rounds, HE rounds should not provide particularly more killing power against fighters due to their higher explosive content. In fact, HE rounds should probably be less effective against single engine fighters than APHE or AP/I rounds. According to Gustin's data (5), MG151/20mm were typically belted with 2 HE (High Explosive). 2 HE/I/Tracer and 1 AP/I. The first 2 rounds (the pure HE) are Mine rounds with the unusually large explosive content. According to Gustin, the HE and HE/I rounds have no armor piercing capability so component armor would tend to provide fairly complete protection from these over the covered angles. The explosion itself of a 20mm round would be fully defeated by the armor in these aircraft. Just for comparison a US hand grenade had 113g of explosives (as opposed to 18.6g for the 20mm mine rounds) and I can't recall anybody every alleging that hand grenades had armor defeating capability against armored cars and halftracks (i.e. vehicles with armor in the 10mm thickness range). Of course, MG151s were also belted with combination of APHE, AP/I, etc rounds. Once a Hispano or MG151 round penetrates to a critical component (cockpit or ammo box for example), if it fuses correctly the target aircraft is very likely to be dead. The important thing is that the round does penetrate. On 26 April 99 Tomb posted the following on AGW concerning a single 20mm Hispano hit on a 109:

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"from a recovered Me109 fighter which had been shot by an AP 20mm cannon shell from a hispano suiza cannon

This shell had penetrated through the rudder ,sternpost, through various members of the fuselage ,the wireless set, two thicknesses of armour plate , both sides of the fuel tank, the back of the pilots seat, through the pilots chest removing the ribcage, through the dashboard, and out the front of the airplane, a most effective demonstration of the power of penetration of the cannon shell.."

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It is not clear if this was an APHE round or a solid round. If this was an APHE round the fuse did not work. If the fuse had worked the round might have exploded in the rear fuselage and demolished the radio, but it wouldn't have killed the pilot and the plane might have made it home.

IMO it is probably inaccurate to assume that the lethality of a round against an enemy fighter is close to being proportional to a simple sum of the average kinetic and explosive energy of the standard belted ammunition. To some extent the WB damage model does do exactly this since single-engine aircraft die far too frequently from "structural failure" and far too little from "critical hits".

I think the major combatants were pretty rational about their choice of armament for their aircraft. US aircraft were armed with .50s because their expected targets were single engine fighters and unarmored Japanese bombers. The theory was that the high volume of fire would result in a higher probability of some hits and that a small number of hits with heavy MG bullets was likely to cripple a single engine fighter since one of those bullets was likely to hit a critical component (pilot, engine, fuel, ammunition, etc..). As the war progressed, the Germans loaded their fighters with more and heavier cannon because they had to shoot down fairly durable 4 engine bombers. Since these bombers had a proportionally much smaller cross section of critical components, redundancy of critical components in the form of multiple pilots and engines, better fire retardant systems than fighters, etc.. they are not very likely to go down with a single critical hit. Therefore it was a safer bet to cause structural failure with HE cannon rounds. The HE mine rounds were not designed in response to any perceived weakness in the ability of 20mm guns to down fighters, but to meet the need of downing bombers.

Here is a quote from an earlier AGW post by ­sick- on this same topic:

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"Contrary to popular belief, bombers were largely unarmored. Fighters, on the other hand, were heavily armored, comparable to modern IFV's in some cases (FW190 for example). This meant that penetrating a bomber was easy, penetrating a fighter was difficult.

In addition, bombers are awful spread out; lots of empty space in there. penetrating a bomber would, very likely, not result in a vital systems hit. fighters, on the other hand, are incredibly compact, with hardly a wasted cubic inch. penetrating a fighter is much more likely to damage a critical system.

This is why German rounds were designed around explosive power. penetrating the bomber was easy; the hard part was delivering enough structural damage to tear it apart. this resulted in the decision to use very high explosive densities and larger and larger rounds, neglecting muzzle velocity, rate of fire and penetrating ability.

Allied rounds (British Hispano-Suiza cannon, American Browning M2) were guns whose design favored penetration. in the case of the M2, this is because its genesis was the 1917 infantry machinegun, where penetration is all important. The Hispano-Suiza was the result of important design tradeoffs, knowing the Germans fielded only light bombers, and knowing that the weapon would have to be multi-purpose.

Also important in this equation is performance against ground targets. ground targets require both penetration and structural damage. they are the most difficult targets, because they are often highly armored, and they don't have that nice 10-20k foot fall to do your dirty work for you. German cannon were not very useful against armored ground targets (although useful enough against trucks and such). the M2 was even, in some cases (like locomotives, where a single penetration can cause a massive steam explosion), more effective. The Hispano-Suiza was highly effective (and thus its use in the typhoon and tempest). the most effective of all, of course, was the Soviet VYa 23mm used on the Il-2. too heavy for air to air work, that gun was a monster tank killer."

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A quick note about Light machine guns: Unlike heavy machineguns, these weapons lack the penetration ability to defeat protective armor in a typical fighter at almost all ranges and angles. This is why they were almost universally abandoned after the early war. These weapons should be very effective indeed against unarmored Japanese aircraft as the high rate of fire should make putting a single incendiary bullet into an unarmored critical component rather easy.

Given that we are not going to get our new damage model anytime soon, what I would like to see is the lethality adjusted so that a single-engine fighter typically goes down with the same number of hits that typically took down a single-engine fighter in real life. Also lethality should not go down as dramatically as it does with range since as I've stated before, heavy machine guns and cannon have sufficient penetration to do the job at any practical range. Given the current damage model, for any particular gun it would probably best to model an ammunition belting which is optimized to kill fighters. If gun lethality against single engine fighters for light machine guns, heavy machine guns and cannon is about right, this probably means that machine guns are somewhat too lethal against buffs, cannon are insufficiently lethal against buffs, and that light machine guns are insufficiently lethal against zeros and the like. However since most engagements are between fighters, this seems to me to be a much better compromise than having heavy machine guns being drastically underpowered against fighters.

(1) "The Browning M2 heavy machinegun", Terry J. Gandler, 1999 PRC Publishing LTD

(2) "America's Hundred Thousand, U.S. Production Fighters of World War Two", Francis H. Dean, 1997 Schifer Publishing Ltd.

(3) "The Great Book of World War II Airplanes", various Authors, 1984 Zokeisha Publications, Ltd.

(4) http://www.geocities.com/Augusta/8172/panzerfaust5.htm.

(5) http://www.geocities.com/CapeCanaveral/Hangar/8217

Hooligan

Luckie Member posted 06-16-99 04:48 PM            

very good Hooligan!

i agree 100% . assigning "hit-points" to aircraft subsystems and assigning "damage-points" based on kinetic energy + explosive energy of the round does not accurately model how things worked. It seriously underestimates the effectiveness of the 50's at long range ( relative to close range at very least ).

i think the best short term solution ( until we get a good damage model ) would be to simply make the damage from a round independant of KE. Killing at long range is still unlikely, since your "bullet density" is reduced due to dispersion ( and the difficulty of putting the rounds on target ). but if the rounds DO hit, they should still do pretty close to the same damage. A Single 50cal should have a chance ( though small ) of killing a plane a mile away.

-luckie

-doing my best to kick ass DESPITE weak guns

Ibex posted 06-16-99 04:51 PM            

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Good work there Hooligan! Glad to see someone on my side. The US did not use 50 cal MG's because they were stupid or because they had no other options.

The US 50 Cal armed planes were very lethal, much more than is showed in the current version of WB.

They came close to having it right in version 2.5, but somehow, when they gave in to the "1000 yard kill naysayers" they went way too far in the other direction.

Take note IMOL.

wulf posted 06-16-99 05:02 PM            

Nice work Hoolign.

One note.

Sick is not entirely correct.

The Germans did not forgo (sp?) velocity, or rate of fire, or penetration with their cannon rounds.

They loaded whatever ammunition type was needed for the mission at hand.

Check out the data posted by vulton sent to him via mail by Mauser (as in the company).

Of special interest...

Effects of various types of cannon rounds.

The apparent overstressed importance of KE when talking about cannon effectiveness.

Why the USN thought the MG 151/20 to be superior to the Hispano.

The apparent ballistic superiority of German cannon rounds *over* Hispano rounds until 1944 or so (exactly the opposite of what was modeled in WB).

...once again, good research. It's not your fault that sources are never 100% correct.

I don't think any gun lethality and airfraft toughness issues can be solved until we have a newer, better damage modeling system.

I don't think it should take 60 .50 MG rounds to kill a fighter everytime.

Mike (wulf)

Cyrano Member posted 06-17-99 01:32 AM            

I guess we are remember what we all said when 2.6 came out. In "Luftwaffe Fighter Aces" of Mike Spick, it's mentionned that pilots often shot at ramming range, close or below 100 meters. I would be happy to keep seeing only close range dogfights and not again long range HO kills. If 20 shots of german 20 mm shot down a b17, then I guess much fewer should be needed to take down a fighter.

Kats posted 06-17-99 02:23 AM            

I think the major combatants were pretty rational about their choice of armament for their aircraft.

OK, I totally agree with this. My comparative lethality is different than yours between the MG151/20 and the 50cal(not incindiary), but the result is the same. Lets take a look.

According to my calculations at max muzzel velocity of concentrated hits:

It should take 5.25 rounds of 20mm to bring down a spitfire or 22.53 rounds of 50cal to do the same. (average, not including magic bullets)

So you say the 50cal should be more lethal, the designers were not stupid? Well, I don't think they were stupid and this is why.

An FwDora with 2 20mm @ 11.85 rps will need .22 of a second burst to land the 5.25 hits.

A P51 with 6x50cal at 12 rps which comes to a .31 of a second burst to land the 22.53 hits.

That IS parity and makes sense to me since the P51 was a long range escort that needed to carry alot of ammo and were not expected to do much buff hunting.

Most pilots liked the .50 gun, but it lacked the power to do structural damage to enemy aircraft. Postwar research demonstrated that only armour-piercing incendiary rounds were really effective, by setting fire to ammunition or fuel. This armament was sufficient for the Mustang, because it was an escort fighter, that had to fight mostly against enemy fighters. The guns were usually set to converge at 300 yards, and 2 degrees above the normal flight attitude. The ammunition supply was relatively large, and that was also beneficial for an escort fighter.

The problem is that the close range lethality is so low, that this slight difference in performance is magnified to the point where you notice a large difference between the two types of rounds.

So just because the 20mm outperforms the 50 cal 4:1, does not make the 50cal a poor descision against a fighter, especially when your mounting 6 to 8 of them! All it means is that a Fwa8 with 4 20mms is overkill against a fighter and the disparity would not be that noticable if the lethality were up to par. The drag and dispersion effects should limit the long range ez kills as well.

That is my opinion, and even though we argue from opposite ends, I believe we agree on the final results.

Maj. Kats

Kats Member posted 06-17-99 02:50 AM            

Just a PS on the Type of 151's we should use in WB.

To destroy armor plates, the LW combined these M-Geschosse with AP/HE and AP/HE/burn rounds, where the AP/HE rounds went through 13mm armor (150kg/mm2) at an angle of 60 degrees.

Since the MA doesn't recreate an Allied/Axis war with 1000's of B17's flying over for the Axis to kill, I think it's unreasonalbe to penalize German a/c because they had a Pure HE shell mixed into their gun belt for anti bomber use. If they were doing fighter sweeps, I doubt they loaded the belts with HE rounds, they would most definalty have used AP-HE rounds.

Maj. Kats

wulf posted 06-17-99 03:04 AM            

kats,

For fighter versus fighter combat (i.e. Bf 109s and Fw 190Ds covering bomber killer Fw 190As in a late war setting...this is only 1 example of several) the loadout was usually along the lines of 3-4 APHE then 1 API.

APHEI was a late war round from what I've read, and generally replaced API rounds from time to time.

The ideal thing(s)...

A new damage model that takes into account blow thru/penetration/overpenetration of rounds (a la the Bf 109 Hispano anecdote) which would really make out APHE rounds to be the killers that they were. A damage model that would model proximity damage, etc., etc., etc.

The ability to choose your own ammunition loadout. Guys who like to fly .50 MG armed aircraft should be able to set up their ammunition based on what they are fighting as well (i.e. nothing but HE and HEI versus most IJA and IJN aircraft, etc.).

A new damage model.

A new damage model.

A newer gunnery model designed to compliment the new damage model - model every round, model the physics of rounds better (bullets and shells fired under the stress of 5 Gs tumble almost the moment they leave the barrel and have a vastly reduced effective range), etc.

Someday we'll see all this. Hopefully we won't see it over the shoulders of our Grandchildren. 8)

Mike (wulf)

DocDoom posted 06-17-99 03:06 AM            

Top job Hooligan.

To echo Wulf, we should not force players flying MG151/20 equipped planes to accept limitations in their ammo just because the Germans had to make this choice to attempt stopping the oblivion of 4 engined bombers.

I also point out that several other issues of balance are also evident.

Hispano/H0-5/SHvak 20mm are MORE effective against bombers in WB, and clearly this was the reverse of reality. When you understand the data Hooligan and Vulton are presenting ... it is obvious that currently an Fw190A-8 is disadvantaged against fighters (fair call with current HE/mine ammo loaded) and is ALSO disadvantaged against bombers. The whole reason history notes the Germans as favouring HE/mine ammo was BECAUSE it performed better against 4 engined bombers than AP did.

In WarBirds, this is a moot feature. HOOF went and did what history told him, but this does not apply to WarBirds as a game of people fighting each other in fighter versus fighter (which is 95% of what we do in WB).

If history had been like WarBirds is, the Germans would easily have elected to load the MG151/20 with AP and we would have less of a problem today in the game, because HOOF would have seen v2.6 coded to reflect this choice

Do not believe for a second this was a choice they could not have made. AP or HE was completely to do with the real world situation of being bombed into oblivion by 4 engined bombers, had roles been reversed you might be surprised how poor the Hispano ballistics were if they had to load flat nosed HE/mine shells. Everything is relative.

What we can do about AP being more effective against bombers than HE is, will take more work than we can expect in the short term. Clearly this double advantage the other 20mm cannons (Hispano/H0-5/SHvak) enjoy does not refect well on the balance that WB might offer in gameplay to its players.

Until you can corrct this ... and when you see what this is telling you ... it is clearly very wrong (as a model) and the best solution for now would be to load the MG151/20 with AP, thus restoring a parity with the model. Individual differences WRT Rof/Mv would of course still be observed.

Somewhere down the track ... we would hope to see the damage model reflect that HE works better against bombers than AP does (not the case currently) and THEN, we can offer players the choice which ammo to load, for their anticipated mission. That is exactly what happened in the real war, and that is WHY history shows the MG151/20 using predominantly inferior ammo against fighters.

We don't get that choice, it is forced upon us. The irony is, should our anticipated mission be shooting down B-17s ... and we take up an Fw190A-8 to do it, complete with its bomber killer ammo load, we would discover a Spitfire does the job better with inferior bomber killing ammo

Clearly ... we have to give the MG151/20 AP ammo as the majority of it's belt loadout ... (just like the others have) until such time as we can EFFECTIVELY model the effects of HE/mine ammo ... and also offer players the choice between the two loadouts.

Until then, you are giving players the choice of using a gun with ammo that does everything better, or everything worse. If you like German planes, then you get the "everything worse" ammo because we like it that way.

This is too transparent

Doc.

wulf posted 06-17-99 03:12 AM            

kats and hoolgn,

One thing to remember about penetration at range and air to air combat (you may know this, probably do, but I wanted to mention it anyway) - the range a round travels in air to air combat is always greater than the range to the target when it was fired.

This tends to explain how in Hades Robert Johnson lived and the numerous reports by LW pilots of the bullet resistant glass of a fighter's windscreen deflecting .50 MG fire from massed bomber formations (for the record, they didn't mention it out of amazement...they mentioned how terrifying it was to have these .50 MG rounds impacting on their aircraft as they were lining up for gun passes).

Mike (wulf)

Kats posted 06-17-99 03:21 AM            

Yes wulf. My opinions are based on ideal firing solutions at MAX muzzle velocity. When my figures show 5.25 rounds of 20mm, in arena combat terms the figure could double or even triple.

Maj. Kats

wulf posted 06-17-99 03:23 AM            

DrDoom,

Straight 2cm AP was only commonly used by the LW (i.e. more than 1 per 5 rounds) for ground attack work against expected armored targets (read: on the Eastern front).

The most common anti fighter rounds were (by far) APHE (rotational deceleration fused), API, and past mid 1944 APHEI.

My best guesses as to why they included AP rounds for anti bomber work are...

1. A little extra oomph in case you wound up shooting at some escorts, but a 'large' HE or HEI round would mess up anything except a P-47 (P-51s and Spitfires weren't rigid designed aircraft and weren't big into armor, unlike the F4U and F6F).

2. Holing fuel tanks to give the HEI and HE rounds something to ignite.

...if anyone has an explanation, it would be cool to know.

Mike (wulf)

DocDoom posted 06-17-99 04:11 AM            

Mike (Wulf)

I am aware of that. I merely point out that in the game called WarBirds, you are forced (when choosing the MG151/20) to use make the same choice when there were other options.

Currently, even if you accept that, you are also forced to accept that the reasons for that choice (better damage ability vs bombers) are not modeled, and that, ironically, the Hispano/H0-5/SHvak with better ammo for fighter combat is also superior for bomber killing duty.

Clearly, WHY we have HE/mine ammo for the MG151/20 is not able to be modeled, and as such, they should dump the idea of using it in WB for the time being. All its doing is causing a bunch of divisive issues while failing miserably to reflect any reality of consequence.

But yes, I understand completely that AP/HEI was not favoured in MG151/20 loadouts in the real war ... I just feel it is stupid to reflect that in WarBirds (currently) because it isn't working like it should, is unbalanced ... and is simulating something real (the need to load according to your mission) when no other factor (of mission) is being simulated in a like manner.

Unless WB suddemly forces all MG151/20 players to attack hundreds of 4 engined bombers, this will not change.

Ironically, even if it did simulate this, the AP/HEI in WB (Hispano/H0-5/SHvak) would do a better job than an Fw190A-8 with twice to four times as many barrels spewing out HE/mine shells would.

THAT ... remains my point.

Sincerly,

Doc.

LawnDart posted 06-17-99 09:46 AM            

Um, I believe that modeling the HE rounds in WB would make them MORE effective against fighters. Primary reason: WB does not model penetration. 100% of the available energy is imparted at point of impact. An AP round would only be round mass x velocity (KE), the HE rounds include a fudge factor which is the explosive component. So granted, the AP is heavier, and may have slightly more energy at short range, at longer range, the KE drops substantially, but the HE fudge factor is a constant.

Result: AP round compared to HE round -- in WB is stronger up close, weaker out far. Make up ur minds. At about 2-300 yds, it's pretty even in most of the discussions and calculations we milled over in the beta.

BTW - HE in a round < 20mm is not a big boom...it's more akin to an expansion enhancer. There generally isn't room for a fuse, so mostly it is just a jacketed round that contains a compound that is volatile when exposed to the air -- or it is a double compartmentized structure whr the compartments blend either at a rotation quotient, or impact (sodium/water, phosphorous -- some explosive, mostly incendiary). With cannon rounds, the larger size allows for a more typicial explosive/fuse combination. Most of the M2 HE rounds i've seen look a lot like some of the handgun rounds out -- hollowed out, something in there...and a wax or other type of seal over the end. Occasionally they are fully jacketed w/ a painted tip to let you know something is inside. AP is jacketed, with a dense core (steel, depleted uranium 8P, tunsten [current, DU isn't used other than some larger cannon rounds now]).

jedi posted 06-17-99 02:22 PM            

Well, right now we have pretty realistic calculations that, sadly, don't yield a very realistic result.

The ideal case, of course, would be a realistic model yielding a realistic result. The big question is: "Would you accept LESS realistic modeling that yielded a MORE realistic result?" Before you knee-jerk to a "no" answer to that, you need to consider...

What destroyed aircraft in real life? We've had posts on this before, but it was mostly pilot kills and critical systems failures and fire. What kills planes in WB? Structural failure (and, since 2.6, pilot kills). Now, the aspects of the structural failure are geared to the "hitting power" of the various rounds, but it's still all just "bullet points" vs "allowable damage points." What this does is emphasize concentration of "impact power" on a specific aircraft part, but almost totally neglects the effect the rounds do on the critical parts of the plane, unless you hit the pilot or engine. Hitting a plane's fuel tank with API rounds means a fire or explosion, either immediately or "soon," not simply a fuel leak. If I hit that same fuel tank with a burst of WB cannon, I probably saw off the wing and get the kill (unless it's a LW 20 or 30mm, in which case there is no damage)

The point is, if the WB model is incapable of reflecting the REAL damage that would be done, then maybe ALL the guns need a boost that allows them to "simulate" the final result. For example, if the fuel tanks in the B-17 are in the wing, and you put a good burst of 20mm into it, it's probably going to catch fire. That fire is eventually going to cause the wing to fail. In WB, all you've done is get close to the max damage points for the wing, and maybe he gets away, or maybe somebody else comes along and finishes him. Wouldn't it be better, more fun, and just as "real" if your burst that would have killed the real B-17 killed the one in WB too?

I'm not saying it would be easy to figure out the correct lethality against each aircraft's systems, and then translate that into increased gunnery punch, but right now there is simply too much emphasis put simply on "impact power," and not enough on "real" damage potential.

I'm just not sure I want to wait for version 3.x to see the guns doing what they should do.

Hooligan posted 06-17-99 02:55 PM            

Kats:

Accepting your following figures:

5.25 20mm rounds to down a fighter (not including magic bullets)

22.53 .50 cals rounds to down a fighter (not including magic bullets)

Given your caveat of very close concentrated fire, 5-6 closely grouped 20mm seems very likely to cause structural failure and WB doesn't seem very far off with an average of 10-12 20mm hits causing complete destruction given that this is an average and the hits are not necessarily closely spaced or at very close range etc. etc.

Now suppose that 1 in 1-4 AP-type rounds has the potential to be a magic bullet. Since there are penetration and fusing issues, I'm going to estimate that 1 in 8 MG151 rounds both penetrates and fuses correctly, neither exploding before it reaches the critical element or failing to explode etc. This means that if 5 MG151 rounds hit, the %chance of a magic bullet kill is (1-(1-1/8) raised to the 5th power) or about 50%. In other words between structural failure and magic bullets, 4 20mm rounds should be very likely to do the trick one way or the other (with structural failures and magic bullets both providing about half of the kills).

Assuming that 1 in 12 .50 cal rounds penetrates and works. Running the math would indicate that 8 .50 cal rounds would give you a 50% chance of a magic bullet. In this case about 12 .50 cal rounds should do the trick (with magic bullets providing the bulk of the kills).

These figures are very rough estimates, but probably the scaling between them (i.e. against a single engine fighter an average of about 3 times the number of .50 cal rounds as 20mm should be required to kill it one way or the other).

The 20mms on the Dora have a rate of fire of 10 rounds/sec in WB (these are synchronized to fire through the propeller). So assuming each round hits this gives us .2 seconds of fire with cannon only or about .15 seconds including the 13mm machineguns. Assuming a more reasonable hit percentage of 10% hits this yields a 1.5 second burst.

The .50 Cals in the mustang have a rate of fire of 12.5 rounds/sec in WB. Assuming each round hits we get .16 seconds. Or with 10% hits a 1.6 second burst.

This means that against fighters a good 20mm should be worth 2-3 .50 cals. All of this seems pretty reasonable to me.

Hooligan

Fletchman posted 06-17-99 06:21 PM            

As I have stated in other threads, Ogre's tests showed the MK108 2.5 times too weak, and the 37mm was 3.5 times too weak. This info is being passed to Hotseat. Up to him to whether he acts on it. IMOL of course knew this all along, but never acted on it. (God knows I told them about it every beta test I did!) I guess Imagic were using the IMOL figures for these guns.

Ogre also tested other guns. Some tested out 10-15% off, which is (considering) probably with the margin of error for this kind of testing.

The "Gunnery Police" (self appointed) will continue to monitor the situation closely. (: