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Weight of Fire FAQ


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FryaDuck #1 Posted 31 March 2012 - 06:26 AM

    Squadron Leader Knucklehead

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One of the recurring questions about the fighter aircraft is the choice of armament. There was considerable change in fighter armament during WWII. Options ranged from rifle-calibre machine guns, with a calibre of about .30 (7.7mm) to 30mm cannon and heavier. People have endlessly defended or criticised the firepower of WWII fighters. The most controversial issue is probably the choice of the .50 machine gun as standard armament of US fighter aircraft. Quite often, the arguments used in this debate are pulled from the air.



Evolution

Generally speaking (with all dangers that are included in generalisations) one can distinguish three phases in the development of World War II fighter armament. (See Tier 1 Aircraft)

Some WWII fighters were armed with was essentially World War I armament: Two machineguns, typically installed in the upper decking of the front fuselage, and with the breeches within reach of the pilot so that he could clear stoppages.



Browning .303 MG

Posted Image


Phase 1
In the first phase the rifle-calibre machinegun was still important. Fighters either carried a homogenous armament of such guns, or they used a mixture of rifle-calibre guns with cannon or heavy machineguns. Examples of the first approach are the eight Browning .303s in the Spitfire and the four MG17s in the early Fw 190. Examples of the second approach are the MG FF and MG 17 weapons of the Bf 109E, the two .50 and four .303 Brownings of the early P-51, or the two 20mm cannon and two 7.7mm guns in the A6M2. The first phase ended when it was generally understood that the light machinegun was ineffective against modern combat aircraft.



Browning .50cal M2
http://spitfiresite....ng-model-m2.jpg




Phase 2
In the second phase there were still two options. Either a homogenous armament of heavy machineguns was used, or a mixture of more modern 20mm cannon with machineguns. The first approach was chosen almost exclusively by the USAAF, which equipped its fighters with six or eight .50 Browning guns. The second approach was far more common, and used by fighters such the Spitfire, the Bf 109, or Ki.84. The cannon were now in general belt-fed, high-velocity weapons with a satisfactory rate of fire. The disadvantage of cannon was that their weight and recoil precluded the use of more than one or two. Hence they had to be mixed with machineguns, with different ballistic characteristics, different ammunition and different maintenance requirements. The disadvantage of an armament of heavy machineguns only was that it lacked the destructive power to be effective against anything but small fighters or lightly constructed bombers.




20mm MG FF
Posted Image

Phase 3
The third phase, which lasted well beyond WWII, was characterized by a switch to a homogeneous armament of 20mm cannon. Examples of such armament are the last Spitfire models, the Typhoon and Tempest, the Soviet La-7, and the Japanese N1K-2J. Usually four 20mm cannon were carried. This was also the standard armament for most post-war fighters, except those of the USAAF. Again, there was a second option: That of heavy "bomber killer" armament. Here the German MK 108 cannon must be mentioned, as installed in the Me 262. Such cannon were either low- velocity, low-rpm weapons, or they were extremely heavy; in either case they reduced the suitability of the fighter for combat against other fighters.

The use of WWII fighter armament ended with the introduction of revolver cannon (developed in Germany during the war), Gatling-type rotary cannon, or Gast-derived dual-barrel cannon. These weapons with their much higher rate of fire revolutionized fighter armament. The introduction of guided missiles came later.



The Weapons

Rifle-calibre machine guns ranged from 7.5mm to 7.92mm. It is should be remembered that for similar calibres, there can still be a large difference in the weight of the projectile. Another important factor is the size of the cartridge case, which determines the amount of propellant and therefore is an important factor in muzzle velocity.

Heavy machineguns have a calibre of about 12.7mm (0.50 inch), in practice that ranges from 11mm to 15mm. The bullet is up to four times heavier than that of a rifle calibre machinegun, and can be fired at a high muzzle velocity. Hence the heavy machinegun usually had very good ballistic characteristics.

Cannons
It is usually considered that 20mm is the smallest practical calibre in which explosive projectiles can be used. Smaller ones have been made, but usually light and heavy machineguns were loaded with a mixture of incendiary and armour-piercing rounds. Such ammunition also existed for 20mm cannon, so the projectile was not necessarily high-explosive. Big cannon were designed for two different roles: Bomber interception and ground attack. The ground attack guns were given a high muzzle velocity for better armour penetration. Bomber killer guns could have a lower muzzle velocity, to achieve a weight reduction.


On Combat Operations (Flying Guns WWII by Williams & Gustin pge 225)

American bombers in the ETO expended 26.3 million rounds of .50 cal ammunition in 1943, and 36.2 million in 1944; the wartime total was 72.3 million rounds. (In October 1943, the ammunition consumption reached a peak of 632,773 rounds per operational day). That corresponds to nearly 12,000 rounds for every enemy aircraft claimed shot down by bombers. Because these claims were often far higher than the actual German losses a more realistic average would probably exceed 40,000 rounds for every destroyed German fighter.  A normal load for a B-17 was 12,000 rounds, but crews often could not resist the urge to take another 2,000 rounds or so in additional ammunition boxes with them. Commanders had to fight this tendency, because the bombers were already heavily loaded and the additional weight could be dangerous, especially if inexpertly stowed. 2,000 belted .50 in rounds weighed 268kg. Considerable effort was made during the war to reduce the weight of the belt links, while providing sufficient sturdiness and flexibility of the belt, which was very important for guns that moved relative to their ammunition boxes.

In comparison, American fighters expended 26.6 million .50 cal rounds and 262,189 20mm rounds, and claimed the destruction of 5,222 enemy aircraft in the air and 4,250 on the ground. that corresponds to 2,810 rounds per enemy aircraft claimed as destroyed. Because the fighter claims were usually much closer to reality, a very rough but reasonable estimate would be that a fighter was ten times more efficient as a gunnery platform than a bomber.
Oderint, dum metuant, tunc ad infernum - Let them hate as long as they fear then go to hell
1st AlphaAce IL-2 (t)(Air)

FryaDuck #2 Posted 31 March 2012 - 06:26 AM

    Squadron Leader Knucklehead

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[size=1]I'll only post suitable data on weapons in the game with minimal info as there is no way to format it. 2.205lb = 1 kg[/size]

[u]Self testing method and formula[/u]: Single battle, fire each weapon group individually over 60 seconds, subtract remaining rounds from total then divide by the number of guns in the group. If you fire all ammunition before the minute is up then figure out how much would make up 60 seconds eg. 45 seconds = 60 rounds, 60/3=20, 45/3=15 therefore 60 seconds would equal 80rpm because you fire 20 rounds in 15 seconds.

[size=5][b]The GUTS[/b][/size]
[color=#800080]0.3.1 Patch[/color]

Normal text = Real data, [color=#0000FF]Blue = Game data[/color]
[color=#ff0000]*[/color] = over real rate
[color=#ff8c00]***[/color] = under real rate
(kg/s = kilograms per second)


[i][u]Rifle-calibre machineguns[/u][/i]

[i]US[/i]
M1919 7.7mm x 56R, 0.099kg/s, 600rpm, [color=#0000FF](600rpm), (0.099kg/s)[/color]

[i]German[/i]
MG 08/18 7.92mm x 57, 0.100kg/s, 600rpm, [color=#0000FF](600rpm)[/color], [color=#0000ff](.100kg/s)[/color]
MG 17 7.92mm x 57, 0.183kg/s, 1100rpm, [color=#0000FF](1200rpm)[/color], [color=#0000FF](.200kg/s)[/color]

[i]Soviet[/i]
DA 7.62mm x 54R, 0.096kg/s
ShKAS 7.62mm x 54R, 0.288kg/s, 1800rpm, [color=#0000ff](0.280kg/s)[/color] [color=#0000FF](1750rpm)[/color]
PV-1 7.62mm x 54R, 0.096kg/s, 600rpm, [color=#0000FF](0.120kg/s) (750rpm)[/color] [color=#ff0000]*[/color]

[center][img]http://www.gallantent.com/images/ww2aircart1.jpg[/img][/center]



[i][u]Heavy Machineguns[/u][/i]

[i]US[/i]
Browning .50cal M2 (12.7mm x 99), 0.606kg/s, 750rpm, [color=#0000FF](750rpm) [/color]
Browning .50cal M3 (12.7mm x 99), 0.970kg/s, 1200rpm, [color=#0000ff](.808kg/s) (1000rpm)[/color]
Colt .50cal MG-53-2 (12.7mm x 99), 0.606kg/s, 750rpm, [color=#0000ff](0.687kg/s), (850rpm)[/color]

[i]German[/i]
MG 131 13mm x 64B, 0.481kg/s
MG 151/15 15mm x 96, (0.490kg/s), (700rpm), [color=#0000cd](0.525kg/s), (750rpm) [/color]

[i]Soviet[/i]
BS 12.7mm UB, 0.680kg/s, 850rpm
UBT 12.7mm UB, 0.840kg/s, 1050rpm



[i][u]Cannon[/u][/i] [size=1](not including explosive potential)[/size]

[i]US[/i]
Colt Mk 12 20mm x 110, 2.166kg/s, 1000rpm, [color=#0000FF](900rpm)[/color], [color=#0000FF](1.950kg/s) [/color]
T9 (M4) 37mm x 145R, 1.416kg/s, 140rpm, [color=#0000FF](120rpm)[/color], [color=#0000FF](1.216kg/s)[/color]

[i]German[/i]
MG FF 20mm x 80RB, 0.996kg/s, 520rpm, [color=#0000FF](300rpm)[/color]
MG 151/20 20mm x 80RB, 1.418kg/s, 740rpm, [color=#0000FF](750rpm)[/color], [color=#0000FF](1.437kg/s)[/color]
MG 213/20 20mm x 80RB, 1.916kg/s, 1200rpm, [color=#0000FF](1200rpm)[/color]
Mk 103 30mm x 184B, 2.310kg/s, 420rpm, [color=#0000ff](300rpm), (1.650kg/s)[/color][color=#daa520]***[/color]
Mk 108 30mm x 90RB, 3.120kg/s, 600rpm, [color=#0000FF](750rpm)[/color], [color=#0000FF](3.900kg/s)[/color]
Mk 214 50mm, 3.850kg/s, 150rpm






[center][img]http://img542.imageshack.us/img542/8590/ammoa.jpg[/img][/center]

[i]Soviet[/i]
B-20 20mm x 99R, 1.280kg/s, 800rpm, [color=#0000ff](750rpm), (1.200kg/s) [/color]
ShKAS 20mm x 99R, 2.880kg/s, 1800rpm, [color=#0000FF](750rpm), (1.200kg/s)[/color]
ShVAK 20mm x 99R, 1.280kg/s, 800rpm, [color=#0000ff](800rpm), (1.280kg/s)[/color]
NR-23 23mm x 152B, 1.833kg/s, 550rpm, [color=#0000FF](850rpm)[/color], [color=#0000FF](2.833kg/s)[/color]
NS-23 23mm x 152B, 1.833kg/s, 550rpm, [color=#0000ff](600rpm), (2.000kg/s)[/color]
Sh-3 23mm x 152B, 2.666kg/s, 800rpm
AM-23 23mm x 152B, 4.166kg/s, 1250prm, [color=#0000FF](1250rpm)[/color]
VYa 23mm x 152B, 2.000kg/s, 600rpm [color=#0000ff]Unknown[/color]







[center][img]http://www.gallantent.com/images/ww2aircart2.jpg[/img][/center]


[b]In Game Aircraft[/b] [color=#800080]Patch 0.3.1[/color]
[color=#FF0000]*[/color]= exceeds real specs

[b][i]Tier 1[/i][/b]
[url="http://en.wikipedia.org/wiki/Arado_Ar_65"]Ar.65[/url], (0.366kg/s), [color=#0000ff](0.200kg/s), (600rpm)[/color]
[url="http://en.wikipedia.org/wiki/Focke-Wulf_Fw_56"]Fw.56[/url], (0.366kg/s), [color=#0000FF](0.400kg/s)[/color], [color=#0000ff](1200rpm)[/color][color=#ff0000]*[/color]
[url="http://en.wikipedia.org/wiki/Boeing_P-12"]P-12[/url], (0.198kg/s), [color=#0000FF](0.198kg/s)[/color], [color=#0000ff](600rpm)[/color]
[url="http://en.wikipedia.org/wiki/Polikarpov_I-5"]I-5[/url], (0.192kg/s), [color=#0000FF](0.240kg/s)[/color], [color=#0000ff](750rpm)[/color] [color=#FF0000]*[/color]

[b][i]Tier 2[/i][/b]
[url="http://en.wikipedia.org/wiki/Arado_Ar_68"]Ar.68[/url], (0.366kg/s), [color=#0000ff](0.200kg/s), (600rpm)[/color]
[url="http://histaviation.com/AGO_Ao_192.html"]AGO Ao 192[/url], (0.200kg/s), [color=#0000ff](0.200kg/s), (600rpm)[/color]
[url="http://en.wikipedia.org/wiki/Grumman_F2F"]F2F[/url], (0.164kg/s), [color=#0000ff](0.164kg/s)[/color], [color=#0000ff](600rpm)[/color]
[url="http://en.wikipedia.org/wiki/P-23_Hawk"]P-23 Hawk[/url], (0.164kg/s), [color=#0000ff](0.164kg/s), (600rpm)[/color]
[url="http://en.wikipedia.org/wiki/Polikarpov_I-15"]I-15[/url], (1.744kg/s), [color=#0000ff](0.240kg/s)[/color], [color=#0000ff](750rpm)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Polikarpov_R-5"]TSh-1[/url], (0.096kg/s)?, [color=#0000ff](0.720kg/s), (750rpm)[/color] [color=#ff8c00]***[/color]

[b][i]Tier 3[/i][/b]
[url="http://en.wikipedia.org/wiki/Focke-Wulf_Fw_57"]FW.57[/url], (1.993kg/s front guns), [color=#0000FF](0.400kg/s)[/color], [color=#0000ff](1200rpm)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Arado_Ar_80"]Ar.80[/url], (.366kg/s), [color=#0000FF](0.400kg/s)[/color], [color=#0000ff](1200rpm)[/color][color=#FF0000]*[/color]
[url="http://en.wikipedia.org/wiki/Grumman_F3F"]F3F[/url], (0.164kg/s), [color=#0000FF](0.164kg/s)[/color], [color=#0000ff](600rpm)[/color]
[url="http://en.wikipedia.org/wiki/Hawk_75"]Hawk 75[/url], (0.328kg/s), [color=#0000FF](0.328kg/s), (600rpm)[/color]
[url="http://en.wikipedia.org/wiki/Polikarpov_I-16"]I-16 type 5[/url], (0.576kg/s), [color=#0000FF](.480kg/s)[/color], [color=#0000ff](1750rpm)[/color] [color=#ff8c00]***[/color]
[url="http://ram-home.com/ram-old/tsh-3.html"]Tsh-3[/url], (0.960kg/s front guns), [color=#0000FF](1.200kg/s front guns)[/color][color=#FF0000] *[/color]

[b][i]Tier 4[/i][/b]
[url="http://en.wikipedia.org/wiki/Bf110"]Bf 110B[/url], (2.724kg/s), [color=#0000ff](0.800kg/s), (1200rpm)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Bf_109_variants#Bf_109_A.2FB.2FC.2FD"]Bf 109C[/url] , (0.732kg/s), [color=#0000ff](0.400kg/s), (1200rpm)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/F2A"]F2A Brewster Buffalo[/url], (2.424kg/s), [color=#0000ff](0.705kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Curtiss_P-36_Hawk"]P-36 Hawk[/url], (.705kg/s), [color=#0000ff](0.164kg/s), (600RPM)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Polikarpov_I-16"]I-16 type 24[/url], (1.856kg/s), [color=#0000ff](1.120kg/s), (1750rpm)[/color] [color=#ff8c00]***[/color]
[url="http://www.ctrl-c.liu.se/misc/ram/lbsh.html"]LBSh[/url], (3.120kg/s), [color=#0000ff](0.460kg/s), (1750rpm)[/color] [color=#ff8c00]***[/color]

[b][i]Tier 5[/i][/b]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Bf_110"]Bf 110E[/url], (3.568kg/s), [color=#0000ff](3.568kg/s)[/color]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Bf_109_variants#Bf_109E_.22Emil.22"]Bf 109E[/url], (2.358kg/s), [color=#0000ff](2.358kg/s)[/color]
[url="http://en.wikipedia.org/wiki/F4F"]F4F Wildcat[/url], (2.424kg/s), [color=#0000ff](2.182kg/s), (Nose 600rpm, Wing 750rpm)[sup]1 [/sup][/color][color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/P-40_Warhawk"]P-40 Warhawk[/url], (1.608kg/s), [color=#0000ff](1.540kg/s)[/color][color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Ilyushin_Il-2"]IL-2[/url], (6.336kg/s), [color=#0000ff](3.136kg/s), [/color][color=#0000ff](1800rpm, 800rpm)[/color][color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/LaGG-3"]LAGG-3[/url], (2.640kg/s), [color=#0000ff](2.640kg/s)[/color]

[b][i]Tier 6[/i][/b]
[url="http://en.wikipedia.org/wiki/La-5"]La-5[/url], (5.760kg/s), [color=#0000FF](2.560kg/s)[/color][color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Ilyushin_Il-2"]IL-2 (t)[/url], (6.176kg/s), [color=#0000FF](3.020kg/s)[/color][color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Bf_109_variants"]Bf 109G[/url], (1.784kg/s) [color=#0000FF](.925kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Me_410"]Me.410[/url], (6.038kg/s front guns), [color=#0000FF](2.270kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/F4U"]F4U Corsair[/url], (3.636kg/s), [color=#0000FF](3.636kg/s)[/color]
[url="http://en.wikipedia.org/wiki/P-51"]P-51A Mustang[/url], (2.424kg/s), [color=#0000FF](2.820kg/s)[/color][color=#ff0000]*[/color]
[url="http://en.wikipedia.org/wiki/P-39"]P-39 Airacobra[/url], (2.628kg/s), [color=#0000FF](2.428kg/s)[/color] [color=#ff8c00]***[/color]

[b][i]Tier 7[/i][/b]
[url="http://en.wikipedia.org/wiki/Goodyear_F2G"]F2G Corsair[/url], (2.424kg/s), [color=#0000ff](2.424kg/s), (750rpm)[/color]
[url="http://en.wikipedia.org/wiki/P-51A_Mustang"]P-51B Mustang[/url], (2.424kg/s), [color=#0000ff](2.424kg/s), (750rpm)[/color]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Me_209-II"]Bf 209A1[/url], (4.082kg/s), [color=#0000ff](1.135kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Bf_109_variants#Bf_109Z_.22Zwilling.22"]Bf 109Z[/url], (6.240kg/s), [color=#0000ff](2.269kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Ilyushin_Il-8"]IL-8[/url], (6.176kg/s), [color=#0000ff](4.126kgs/)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Lavochkin_La-9"]La-9[/url], (7.332kg/s), [color=#0000ff](4.800kg/s), (750rpm)[/color] [color=#ff8c00]***[/color]

[b][i]Tier 8[/i][/b]
[url="http://en.wikipedia.org/wiki/XF5U"]F5U Flying Flapjack[/url], (3.636kg/s), [color=#0000ff](4.122kg/s), (850rpm) [/color][color=#ff0000]*[/color]
P-51 Jet, ????, [color=#0000ff](4.122kg/s), (850rpm) [/color]
[url="http://en.wikipedia.org/wiki/Me_609"]Me 609[/url], (10.860kg/s), [color=#0000ff](7.800kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Me_262"]Me 262[/url], (12.480kg/s), [color=#0000ff](7.800kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Lavochkin_La-150"]La-150[/url], (2.560kg/s), [color=#0000ff](2.400kg/s), (750rpm)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Ilyushin_Il-10"]IL-10[/url], (4.226kg/s), [color=#0000ff](4.126kgs/)[/color] [color=#ff8c00]***[/color]

[b][i]Tier 9[/i][/b]
[url="http://en.wikipedia.org/wiki/FJ-1_Fury"]FJ-1 Fury[/url], (3.636kg/s), [color=#0000ff](3.636kg/s), (750rpm)[/color]
[url="http://en.wikipedia.org/wiki/F6U"]F6U Pirate[/url], (8.664kg/s), [color=#0000ff](7.800kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Me_109TL"]Me 109TL[/url], (13.516kg/s), [color=#0000ff](10.674kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://www.luft46.com/mess/mep1099b.html"]Me P.1099B[/url], (3.850kg/s), [color=#0000ff](15.600kg/s)[/color] ???
[url="http://en.wikipedia.org/wiki/Ilyushin_Il-20_%281948%29"]IL-20[/url], (10.664kg/s), [color=#0000ff](8.000kg/s)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/Lavochkin_La-160"]La-160[/url], (3.666kg/s), [color=#0000ff](4.000kg/s), (600rpm)[/color][color=#ff0000] *[/color]

[b][i]Tier 10[/i][/b]
[url="http://en.wikipedia.org/wiki/La-15"]La-15[/url], (5.500kg/s), [color=#0000FF](8.499kg/s)[/color] [color=#FF0000]*[/color]
[url="http://en.wikipedia.org/wiki/Ilyushin_Il-40"]IL-40[/url], (16.664kg/s front guns), [color=#0000FF](16.664kg/s)[/color]
[url="http://en.wikipedia.org/wiki/Messerschmitt_Me_262"]Me.262HG III[/url], (7.664kg/s), [color=#0000FF](7.664kg/s)[/color]
[url="http://www.luft46.com/mess/mep1102.html"]Me.P.1102[/url], (9.240kg/s), [color=#0000ff](6.600kg/s) (300rpm)[/color] [color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/F-86A_Sabre"]F-86A Sabre[/url], (5.820kg/s), [color=#0000FF](4.850kg/s) [/color][color=#ff8c00]***[/color]
[url="http://en.wikipedia.org/wiki/F7U_Cutlass"]F7U Cutlass[/url], (8.664kg/s), [color=#0000FF](7.800kg/s)[/color] [color=#ff8c00]***[/color]

[sup][color=#0000ff]1[/color] [/sup]Guns and cannon firing through the propellor arc have a lower rate of fire than guns/cannon that do not due to syncronisation. There are two basic types, mechanical and electrical, generally mechanical are a slower rate and electrical are higher because the rounds are electrically fired. Syncronised guns never fire at the max cyclic rate of fire. Historically, the 7.62mm ShKAS fired at 1800rpm when mounted in the wing and 1625rpm when mounted in the cowling.


Now that you have all of this data the discussion can begin.

[u]Update[/u]
[i]Some things to note[/i]

A bullet when fired will exert a kinetic energy (KE) impact on the object it hits, [img]http://upload.wikimedia.org/wikipedia/en/math/2/3/1/231cfd9416f4736f5ee8d102ee84cb22.png[/img] being the classic calculation. A bullet passing an observer has kinetic energy in the reference frame of this observer. The same bullet is stationary from the point of view of an observer moving with the same velocity as the bullet, and so has zero kinetic energy. Most muzzle velocity of LMG/HMG ammuntion is between 700-900m/s or 2013mph. 500kph airspeed = 138.888m/s so you're never going to go faster than a bullet with aircraft in this game. It would reduce the kinetic energy of the hit and damage caused.

A cannon shell on the other hand has not only the above KE effect but also a chemical energy (CE) effect from the explosion of the shell (as well as fragmentation). I won't throw Gibbs–Duhem equations at you because that would be too much like going to school.

[i]How this may translate to you[/i]. A phillips head screw driver is about the same size as a bullet, an adult male could easily punch a hole in cloth even if it were stiffened with aircraft dope. Aluminium skin of an aircraft (in this game) is not much thicker than a can of soft drink, most teenagers can punch holes in a can of coke, pepsi, dr pepper or whatever they drink nowdays. The aluminium skin is a method of streamlining and construction stiffness not protection.

[i]What about armour plate?[/i] A general rule for the game in this era is "If the round has a diameter greater than the thickness of the plate it will penetrate". So 20mm will penetrate 12mm (1/2 inch) armour plate. You should note too that the German high explosive mine shell had a delay fuse so it would explode once it got through the armour plate. Of course if the cannon shell was fired into a Tier 1 aircraft it may not explode because it does need to hit something solid like the engine, fuel tank, oh and the pilot.


[b]Why the USAAF, USN and USMC didn't use Cannon[/b]

It isn't true that all US aircraft during WWII only used .50 machine guns. The P-38 Lightning, P-39 Airacobra, P-63 Kingcobra, and P-61 Black Widow all mounted various types of cannon. It is also not true that the .50 cal was standardised early on. In fact, when the US entered the war it had fallen way behind in the development of armament for combat aircraft, because very limited resources had been available between the wars. They did have a very reliable .50 cal machine gun, the M2, which became "standard". There were many attempts by manufacturers to get a 20mm cannon as reliable as the .50 cal, nearly every US fighter at an early stage of development had 20mm cannon fitted. Because of failures in the weapons (design and manufacturing) and limited ammunition amounts, as compared to the .50 cal, that the .50 cal became by default standard.






[center][img]http://www.ozatwar.com/ozatwar/os01a.jpg[/img][/center]

In the Pacific, fighter tactics were developed and confirmed against Japanese aircraft captured or recovered then tested by the [url="http://www.ozatwar.com/usaaf/atiu.htm"]ATIU[/url] at Hangar No 7 Eagle Farm airport, Brisbane QUEENSLAND Australia. This made life much easier for Allied pilots as they had accurate knowledge of how to engage the enemy. It was ATIU who gave the code names for Japanese aircraft;


[quote][font=Arial][size=2]Technical Sergeant Francis Williams suggested that using people's nicknames would make it easy for service personnel to relate an aircraft type to a profile. Fighters and float planes were given male names, and bombers, reconnaissance aircraft and flying boats were assigned female names. At a later stage transport aircraft were named with a "T" name, training aircraft were named after trees and gliders were named after birds. The Japanese aircraft naming system was apparently know as the MacArthur Southwest Pacific Code Name System. Capt Frank T. McCoy's Tennessee hill-country background showed up in some of the names that were chosen such as "Rufe", "Luke", "Nate" and "Zeke". The list became extensive with eventually of 50 names on the list. Frank McCoy said that "Sally" was named after his Group Commander's wife , "Claude" was named after an Australian friend, and "Joyce" was named after a WAAAF who worked in his section. Many were named by Technical Sergeant Francis Williams. Williams name "Betty" after a well-endowed nurse that he knew.[/size][/font][/quote]





[b]The Debate - Volume of Fire vs Weight of Fire[/b]

Most people who fly sims etc are on one side of the fence or the other. The US pundits say that volume with extra weight of the HMGs is better than weight plus explosive potential. Yet we see that the F4U Corsair fires the same weight as the F-86A Sabre but today you'd never see a .50cal as main armament in a Class A fighter. Which side are you on and why?

[u][b]The Debate - Conclusion[/b][/u] why Weight of Fire will always be greater than Volume of Fire (for WWII aircraft)

With four Hispano Mk.V cannon, the [url="http://en.wikipedia.org/wiki/Hawker_Tempest"]Hawker Tempest Mk V[/url] could be considered the best-armed fighter of WWII. For combat against other fighters, or ground attack against soft or lightly armoured targets, this was the best combination of the time. It combined a high rate of fire (four x 750rpm) with an adequate muzzle velocity (840m/s) a heavy projectile (130g) with good armour penetration and an effective incendiary or explosive load. The 6.5kg/s throw weight of this installation was only exceeded (and greatly so) by fighters that had multiple low-velocity 30mm cannon, such as the four Mk 108s of the Me 262. Thes low velocity weapons were suited exclusively for bomber interception. The four cannon of the Tempest Mk V had a combined muzzle power of nearly 2300kW. For comparison, the four MK 108 cannon of the Me 262 delivered 1,680kW, and the six .50cal Brownings installed in most American fighters 1375kW.

The muzzle power in kilowatts (SI units) is the kinetic energy (in thousands of joules) of the projectile multiplied by the total rate of fire. For the Hispano Mk V and MK 108 the kinetic energies of the individual projectiles are not far apart: 46900 joule for the 130g HE round of the Hispano, and 42100 joule for the Mk 108s [i]330g [/i][i]Minengeschoss[/i] projectile. The advantage in muzzle power of the Hispano derives from its 25% higher rate of fire. There is a vast difference in the chemical energy stored in the rounds because the Hispano HE round contains only 10g of explosive, and the MK 108 round between 72 and 85g. As TNT releases 4200 joule per gram and PETN 6400 joule per gram, the chemical energy stored in the [i]Minengeschoss[/i] projectile is at least seven times larger than its kinetic energy. The .50 cal round has no chemical energy.


[u][i]So why did the USAAF etc do so well?[/i][/u]

15:1 US:German fighter aircraft ratio
Adequately trained pilots as opposed to basically trained pilots (mostly)
Firing nearly three aircraft loads of ammunition per kill

[i]How does this translate in the game?[/i]

Start a training battle with only you in a Bf109G vs 15 others in P-51s or Corsairs. See if you win.

[u][b][color=#FF8C00]NOTAM[/color][/b][/u]

[color=#696969]as at 0.3.1 Patch[/color]
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__Traxxas__ #3 Posted 31 March 2012 - 07:34 AM

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Nice read, +1


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SlavGun #4 Posted 31 March 2012 - 09:47 AM

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thx

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Reschke #5 Posted 03 April 2012 - 01:48 PM

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Do you mean the weight of the weapon or the rate of fire of the weapon? Two completely different things there. On some aircraft they had a lever that would allow a pilot to clear a jam but most times the jams were unable to be cleared from the weapon at all due to factors like G loading, etc...
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von_Krimm #6 Posted 04 April 2012 - 06:23 PM

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Frya, are you using the RoF for the M2/AN version of the M1919 or the RoF for an infantry-support model?  Reason I ask is the the AN had a RoF around 1200-1500 rounds, which is comparable/slightly superior to the MG 17 and comprable/slightly inferior to the ShKAS.  The Army-Navy version for aircraft used a lightend bolt/reciever/barrel assembly that allowed it to have a RoF 2.5-3 times that of the ground version.
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FryaDuck #7 Posted 05 April 2012 - 12:35 AM

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View PostvonKrimm, on 04 April 2012 - 06:23 PM, said:

Frya, are you using the RoF for the M2/AN version of the M1919 or the RoF for an infantry-support model?  Reason I ask is the the AN had a RoF around 1200-1500 rounds, which is comparable/slightly superior to the MG 17 and comprable/slightly inferior to the ShKAS.  The Army-Navy version for aircraft used a lightend bolt/reciever/barrel assembly that allowed it to have a RoF 2.5-3 times that of the ground version.

I never post data unverified and not checked in game. Something you could have done in game yourself rather than questioning the veracity of my thread. Suffice to say neither are in the game.

I can confirm that both AN versions did have a cyclic rate of fire of 1200rpm. This would give the .30cal M1919 AN/M2 (0.198kg/s) and the .50cal M3 (0.970kg/s).

Note: I will update my post on the M3 as it's fitted to the F-86A Sabre but not in game which will need to be corrected by the devs.
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Ltngstrike #8 Posted 05 April 2012 - 03:09 AM

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Hey Frya, good stuff here.  I fixed a neg rep for ya on your last post.   :Smile_sceptic: Someone's finger musta slipped.  :Smile-_tongue:

Something that would help me to evaluate firepower better would be listing the rate of fire along with the weight of fire.  I notice many of the lower tier aircraft have a rather slow RoF even though they seem to have comparable WoF.  The difference can be huge at times.


FryaDuck #9 Posted 05 April 2012 - 04:45 AM

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View PostLtngstrike, on 05 April 2012 - 03:09 AM, said:

Hey Frya, good stuff here.  I fixed a neg rep for ya on your last post.   :Smile_sceptic: Someone's finger musta slipped.  :Smile-_tongue:

Something that would help me to evaluate firepower better would be listing the rate of fire along with the weight of fire.  I notice many of the lower tier aircraft have a rather slow RoF even though they seem to have comparable WoF.  The difference can be huge at times.

Well the easiest way to figure out the rate of fire (over 1 minute), do it in single battle, is;

ammo start - ammo finish / number of guns = rate of fire

eg P.12: 4000 - 2800 / 2 = 600rpm which is the cyclic rate for the M1919 7.62mm

Now there can be a margin for error because I'm not perfect in my own verification (+/-50rpm roughly), and compared with my own written data from 30 different sources which I've researched over 40 years. Also the devs can change the rpm or weight or explosive information in the game for balancing purposes. The thread does not need to die an unnatural death because of disinterest. Therefore, if you wish to test independently of my data then please do, and post it. I'll add the info to the weapons independently confirmed.

BTW thanks for the +1 but don't worry about it, I probably got that because of the tone of that post rather than content.


Everyone: What is your tested rate of fire for the FW.57 front guns?


M1919, .50cal M2 & M3 updated.
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Ltngstrike #10 Posted 05 April 2012 - 10:33 AM

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I talked to FryaDuck in game last night and have conducted some tests on gun rate of fire in Single Battles.  I used a stopwatch and flew around the map firing continuously until I ran out of ammo or the guns quit firing.  Yeah, I know Crash, Fry, Aces, battle as usual for me eh?   :Smile_trollface:    :Smile_teethhappy:

To keep things organized I have copied and pasted FryaDuck's list of aircraft and I will add my resulting rate of fire to his list using a different color.

*NOTE* On almost all aircraft my guns quit firing before the ammo indicator showed that I was out of ammo.  Repeated tests showed the guns quit firing after the exact same time period but remaining ammo varied between 0 and 1200 in one case.  This may be due to ping, fps, etc... or it may be a glitch in the ammo indicator.  The "x 2", "x 4", etc... indicates how many guns are on each aircraft but the rpm is for each individual gun.  Edited to add total sustained burst time in seconds inside these brackets "{ }"

In Game Aircraft

Tier 1
FW.56 (0.200kg/s)  600 rpm x 2 {200 sec.}
P-12 (0.198kg/s)  600 rpm x 2  {200 sec.}
I-5 (0.192kg/s)   750 rpm x 2  {160 sec.}

Tier 3
FW.57 (1.993kg/s front guns) 300 rpm x 2 [I only tested the front guns]  {180 sec.}, (1.150kg/s)
Ar.80 (.366kg/s)  1200 rpm x 2  {100 sec.}
F3F (0.164kg/s)  600 rpm x 2  {200 sec.}
Hawk 75 (0.328kg/s)  600 rpm x 4  {200 sec.}
I-16 type 5 (0.576kg/s)  2000 rpm x 2 {90 sec.}, (.640kg/s)
Tsh-3 (0.960kg/s front guns)  750 rpm x 10  {160 sec.}

Tier 6
La-5 (5.760kg/s)  738.461 rpm x 2  {65 sec.}
IL-2 (6.336kg/s)  738.461 rpm x 2, 20mm{65 sec.}, 2000 rpm x 2, 7.62 {90 sec.}
Bf109G (1.784kg/s)  750 rpm x 1, 20mm {72 sec.}, 1200 rpm x 2, 7.92  {100 sec.}
Me.410 (6.038kg/s front guns)  3000 rpm x 1, 20mm {72 sec.}, 2400 rpm x 2, 7.92mm {100 sec.}
F4U (3.636kg/s)  750 rpm x 2  {100 sec.}
P-51A (2.424kg/s)  750 rpm x 4  {100 sec.}
P-39 (2.628kg/s)  120 rpm x 1, 37mm {30 sec.}, 750 rpm x 2, .50 cal.{80 sec.} The only aircraft tested that continued to fire after the ammo counter indicated zero.  4 additional shots after the counter shows zero.

Tier 10
La-15 (8.499kg/s)  833.33 rpm x 2  {72 sec.}
IL-40 (16.664kg/s front guns)  1200 rpm x 4  {50 sec.}
Me.262HG III (7.664kg/s)  1500 rpm x 4  {36 sec.}
Me.P.1102 (12.48kg/s)  750 rpm x 4  {60 sec.}
F-86A (5.820kg/s), (3.636kg/s) 1200 rpm x 6  {55 sec.} - in game gun incorrect should be M3 version but M2 version is modelled.(vonKrimm)
F7U (8.664kg/s)  981.81 rpm x 4  {55 sec.}

:Smile_honoring:

Edited 5/4/12 to include sustained burst times
          Edited 5/8/12 to complete data



GeorgePatton #11 Posted 05 April 2012 - 03:28 PM

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Nice read, +1... but I want ALL the equations... I'm taking AP physics, so I like this stuff. lol


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g0rr3w #12 Posted 05 April 2012 - 07:14 PM

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so that kg/s is the amount of lead the planes spit out? because the numbers feel about right damage output wise
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FryaDuck #13 Posted 05 April 2012 - 10:24 PM

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View PostGeorgePatton, on 05 April 2012 - 03:28 PM, said:

Nice read, +1... but I want ALL the equations... I'm taking AP physics, so I like this stuff. lol


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View Postg0rr3w, on 05 April 2012 - 07:14 PM, said:

so that kg/s is the amount of lead the planes spit out? because the numbers feel about right damage output wise

Per second yes. I don't know if they feel right but we need a point of reference so putting up the faq and updating it will give an idea.
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GeorgePatton #14 Posted 05 April 2012 - 11:33 PM

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View PostFryaDuck, on 05 April 2012 - 10:24 PM, said:

No freebees here, I had the learn them the hard way so can you :)


So you mean you don't know them yet? :P


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FryaDuck #15 Posted 05 April 2012 - 11:35 PM

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View PostGeorgePatton, on 05 April 2012 - 11:33 PM, said:

So you mean you don't know them yet? :P


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Oh I know them...and the interwebs helps me remember too!!! :P
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GeorgePatton #16 Posted 06 April 2012 - 01:22 AM

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Haha, can't wait to get that far in my course. :) I hope it'll be in there...


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drkorf #17 Posted 06 April 2012 - 05:14 AM

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The definitive reference for aircraft guns is "Flying Guns of World War II" by Anthony Williams and Emmanuel Gustin. Appendix 6 is particularly useful for game development as it rates the effectiveness of each weapon system with a combination of KE and CE. Looking at tables 1 and 2, you get the idea that the US .50 was not a very efficient weapon. On a pound per pound basis, it was about half as effective as a 20 mm cannon. But since the US was generally shooting down fighters and not bombers, the lack of power was not so important. The M2 trajectory was pretty flat too, which is good for aerial combat. In contrast, the Mk108 cannon was devastating against bombers, needing only a few hits to take down a heavy. But at 500 m/s, you need to be an expert to hit in a dog fight. I hope WoWP models the guns correctly. I've seen some massive errors in other games.

FryaDuck #18 Posted 06 April 2012 - 12:18 PM

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Yes drkorf that is one of my research references but I wouldn't call it definitive, much like the mandatory Chamberlain, Doyle and Jenz for WWII German Armour. Certainly a must have for historians also having unrestricted access to, in my case, the AWM and RAAF Museum archives helps. Notwithstanding, of course, the other 40 years or so of time invested.

You may be disappointed that the trajectory of the Mk108 doesn't drop off as much as it could. That is mainly because of the restricted range of the guns in the game and 600m is negligible after a 1 second of flight.
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drkorf #19 Posted 06 April 2012 - 01:55 PM

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When pulling Gs, the Mk108 will look a lot different than M2 though. In that respect, a flatter trajectory makes the M2 easier to use. I am a huge fan of the Mk108 though.

eug_dirtbag #20 Posted 08 April 2012 - 06:32 AM

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A couple of thoughts, still downloading so no in game reference so far.

Type of ammo as some effect, as noted above MG's in particular tended to have a mix.  I don't have my materials handy but I believe beyond the standard tracers.  Ball, basically your standard bullet, AP and incendiary could be mixed.

Also convergence, the point where all a the rounds for all the guns hit the same point, this varied somewhat from aircraft to aircraft within a type but was generally the same across a type.
So all ME 109 G's guns would be set at a common point of convergence.  I believe in general between 200 and 400yds was common, at ranges out side those the guns are less effective. particuylarly against smaller fighter sized targets.

Lastly the amount of ammo carried, and MG armed fighter generally carried more ammo than a cannon armed fighter, often a lot more.  So although a single hit by a cannon armed fighter is more devastating it takes a better pilot and more care to effect a hit.  An MG armed fighter with more rounds per gun would get more chances to effect enough damage to take out an enemy aircraft.

Possibly the best comparison being a Me 262 with 100 / 80 rnds per gun vs a P51 with 400/ 270 rnds per gun.  In time of fire (always a little iffy) that works out to 10 seconds for the 262 vs 32 for the P51  Call it 3 bursts to 10 so the P51 pilots has 7 more attempts to make a succesfull hit.




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