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WW2 Plane with most Firepower?

Discussion in 'Aircraft' started by Pride_of_Lenin, Mar 7, 2015.

  1. Poppy

    Poppy grasshopper

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    Weren't the F's and G's kinda heavy, more of bomber destroyer than fighter. They needed a buch of add ons in order to reach bomber streams.
    The 109 was past its' prime, and the FW took its place as the leading edge.
    Maybe.
     
  2. mac_bolan00

    mac_bolan00 Member

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    the brits at the time of BoB still had a humungus stock of .303 ammo left over from the great war. so mounting 12 303 mg's in a plane wasn't so ridiculous.
     
  3. Carronade

    Carronade Ace

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    They weren't intended to be, but the Gs in particular came to be loaded down with underwing cannons and even rocket tubes, which hurt their performance - and they'd no sooner beefed up their armament against bombers when the Americans started deploying long-range fighters.

    The basic 109F, G, or K remained a capable fighter, and some attempts were made to use them against Allied fighters while more heavily armed types or FW-190s concentrated on the bombers, but it didn't always work out so neatlly in combat.
     
  4. Sheldrake

    Sheldrake Member

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    The British started WW2 with 8 x 303 as a standard fighter armament,based on trials which showed a burst would shred a 1935 aircraft. By 1940 aircraft were tougher and the 8 x 303 was demonstrably inadequate against German bombers, many of which survived despite being riddled with 303.

    Even in 1940 there were trials of 2 x 20mm cannon.in Spitfires of No 19 sqn. This did not work well and there were problems with ammunition feed. I think in order to fit the cannon in a spitfire wing it had to be rotated and operate on its side. Cannons were initially seen as unreliable and No 19 Sqn ended the Battle of Britain with machine gun armed spitfires. The 12 x 303 mounting for the Hurricane II B was another way to increase fire-power. The result was a heavy Hurricane with less firepower than a 2 cannon spit VB or a 4 cannon Huirricane IIC.

    The Me109F was introduced in 1940 and mounted a single 20mm and 2 x 7.7 mm machine guns. This looked like a reduction in firepower compared to the Me109E which had 2 x 20mm and 2 x 7.7mm MGs. However the single cannon was mounted on the centre line and had a higher MV than the 20mm mounted in the wings of the 109E. The 1942 Me109G had a more powerful engine than the 109F and mounted 2 x 12.5 mm machine guns in the cowling in place of the rifle calibre in the 109F. By this time the Germans faced heavily armed and armoured US four engined bombers and they needed a lot more firepower. Hence the under slung 20mm cannon that could be added to the 109G.

    The likely targets will influence how much firepower is enough and what constitutes extra weight. The USN facing light ly constructed Japanese aircraft considered 4 x 50 cal adequate. The RAF and FAA faced more heavily constructed German bombers with self sealing tanks and armour thought the extra two were worth while. The RAF also preferred 6 x 50 cal for their P40 and P51 aircraft. The Germans had the problem of facing a mix of light high performance fighters and very heavy bombers. A single hit from a well aimed single centre mounted 20mm would be good enough to knock down a single engined fighter, but utterly inadequate to bring down a B17 or B24 which needed around twenty(?) 20mm cannon hits or three from a 30mm cannon. . .

    .
     
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  5. Carronade

    Carronade Ace

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    The Me109F originally had a 15mm cannon, the MG151, along with the two 7.92mm MGs. The MG151 was a good weapon, but the shell was considered too light, so it was redesigned as a 20mm, designated MG151/20. Since it used a necked cartridge this was a relatively easy redesign. The MG151/20 in the nose or Motorkanone installation had 200 rounds whereas the FFs in the wings only had 60/gun, so the loss of firepower was more apparent than real. Having all three guns in the nose avoided the need to harmonize wing guns at a particular range.

    These guns used electrical firing, so synchronizing for the MGs was just a matter of interrupting the electical circuit rather than having a mechanical interrupter system. This kept the reduction in rate of fire down to about 10%, whereas mechanical systems could lose as much as 40%.

    The later 109Gs had 13mm MG131 machine guns, so by the rule lwd stated in #51 above their effective firepower was not much less than six .50s in the wings. Also some of the later Gs and Ks had 30mm nose cannons.
     
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  6. USS Washington

    USS Washington Active Member

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    I appreciate the replies and commentary you both gave, very informative, I know this ain't much of a reply and doesn't really continue the discussion but sometimes I'm just not sure how to add to these conversations.
     
  7. Slipdigit

    Slipdigit Good Ol' Boy Staff Member WW2|ORG Editor

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    One thing to consider when adding up diameters of weapons is that three 3in guns in not the same as one 9in gun in terms of the total weight of the projectiles and thus in the amount explosive carried. A circle 1in in diameter does not have half the area of a 2in circle (3.14 square inches vs 12.57).
     
  8. lwd

    lwd Ace

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    If you double all the linear dimensions of an object then you multiply the volume by 8. If you are talking solid KE rounds that means doubling the diameter and keeping the volume constant results in a round with 8 times the KE. However the wall thickness doesn't necessarily scale with HE rounds so that doubling the dimensions may result in carrying more than 8 times the filler and since the energy in the HE is significantly greater than the KE even in fairly small rounds this can be very telling.
     
  9. Poppy

    Poppy grasshopper

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    There was an informative thread where we discussed the engine hub mounted 109 connon.
    Was it the cannon firing through hub, causing overheating - or was there ever cannon mounted above the engine, firing through propeller arc?
    Thinking the reason they put 20mm gun underwing is because hub firing cannon was an issue...i dunno.

    Also wonder about a slower firing, lower velocity cannon round. It'd seem like one would have to kind of lob the round, where the heavy machinegun round would fly flatter/faster. Just curious.

    "I think the equation was usually 3 .30 cal were the equivalant of 1 .50 cal and 3 or 4 .50 cals the equivalant of a 20mm that's as far as impact damage goes."...great info, tks. ...12- .30's equals 1 -20mm. wow.
     
  10. Carronade

    Carronade Ace

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    IIRC one of the Me-109K models had 15mm cannons in place of the synchronized machine guns.

    Many FW-190 models had MG151/20 cannons in the wing roots, synchronized for firing through the propellor arc. The original 190s had 7.92mm MG there.

    The Soviet La-5, 7, 9, 11 had 2-4 20/23mm cannons in the nose, firing through the propellor. These used radial engines which cannot accommodate a hub gun.

    As I recall the Germans had experimented with a Motorkanone in the 109E but it proved impractical, but they were able to mount two 20mm FFs in the wings. The 109F was a major redesign which apparently resolved the issues with the hub mounting, but it also had thinner wings and could not accommodate internal cannons. One cannon and two MGs were considered adequate for engaging fighters, especially when they upgraded to 20mm and 13mm, but there was no internal space for additional weapons for anti-bomber work, hence the underwing gondolas.

    Adolf Galland flew a specially modified F for a time which did have internal wing cannons, but apparently this was not something that could be generally adopted.
     
  11. lwd

    lwd Ace

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    Normally I see anything under 20mm considered a machinegun rather than a cannon. Did the 15mm have explosive shells?
     
  12. Carronade

    Carronade Ace

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    It did, but the 15mm shell was felt to be too light, so the weapon was redesigned as the MG151/20.
     
  13. lwd

    lwd Ace

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    Interesting wiki refers to it as a cannon as well but the MG would indicate machinegun rather than cannon. Makes me wonder what's going on.
     
  14. Carronade

    Carronade Ace

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    Apparently that was just German practice, the 20mm Oerlikon derivative was also designated MG FF. I suppose the theory was that it was the same basic mechanism regardless of size or type of ammuntion. AFAIK they only started using MK for the 30mm types, not sure why they made the switch at that point.
     
  15. lwd

    lwd Ace

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    They may have defined cannon as starting at 30mm. The US practice was 20mm I belive. The 151 started as a 15mm weapon which would have meant it was a machinegun under US and it looks like under German defintions. When it was upgraded to 20mm it would have become a cannon by US defintion but since the mechanism was essentially the same the Germans kept their terminology (if the Germans did define cannon as starting at 30mm it was still a mg for that reason as well). The question becomes why the insistence of some sources in calling it a cannon. Looking around some make the point of whether or not they could fire explosive ammo. I think there were some fairly early trials of explosvie ammo for the 12.7mm but up through WWII 20mm was taken to be the dividing point where it became worth while. All relativly arbitrary so why the insistence (not you but from some sources) that the German 15mm was a cannon? Especially given that the Germans used an abreviation indicating it was a mg? Might be similar to the argument as to whether or not the twins were battleships or battlecruisers.
     
  16. Carronade

    Carronade Ace

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    The guns in underwing pods were 37mm, on the Ju-87G.

    The Ju-87D-5 had two MG151/20 cannons (20mm), one internal in each wing, replacing the earlier 7.92mm machine guns. The Ju-187 would also have had two MG151/20s in the wings.

    The old Squad Leader/Cross of Iron game included a Stuka which could attack with both 20mm and 37mm guns, but I have not seem any other reference to this. Ju-87Gs were often converted from Ds, but I have not seen specifically whether they were D-5s or earlier models.
     
  17. Dave55

    Dave55 Member

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    The various IL-2s had 20mm, 37mm, rockets and bombs, depending on the variant, so they packed a punch.
     
  18. Sheldrake

    Sheldrake Member

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    I wonder if the Germans defined their 20mm cannon as "Machine Guns" so they could be classed as "heavy machine guns" under the Versailles treaty. The arms control clauses listed the numbers and types arms that Germany was allowed to have. http://net.lib.byu.edu/~rdh7/wwi/versa/versa4.html
    Note that there is no allowance for Germany to possess a smaller calibre cannon than 7.7 cm. Defining a 20mm cannon as a "heavy machine gun" would allow the Reichswehr to possess anti tank weapons.
     
  19. FalkeEins

    FalkeEins Member

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    Zerstörergeschwader 26 Me 410 toting 50 mm Bordkanone BK 5 cannon ( with 21 rounds)

    Bf 110 equipped with a 37mm Flak 18 gun and twin W.Gr. mortars under the wings!
     
  20. lwd

    lwd Ace

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    The problem with that at least for the mg151 is that according to wiki: https://en.wikipedia.org/wiki/MG_151_cannon
    At that point I don't think the Germans really cared what the Versailles treaty said. And for the 151 there is the fact that it started out as a 15mm weapon. On the otherhand looking at:
    https://en.wikipedia.org/wiki/MK_101_cannon
    Which indicates that even a 30mm was oritinally classed as an MG. Whether or not this was due to a change in terminology or an attempt to evade Versailles is a good question.
     

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