What is the biggest cannon that would fit in a P39 nose?

Discussion in 'Weapons Systems Tech.' started by pinsog, Dec 11, 2011.

  1. pinsog

    pinsog Member

    Joined:
    Jan 20, 2008
    Messages:
    658
    Likes Received:
    15
    Trophy Points:
    18
    If you stripped all the armament out of a P39's nose, what is the biggest, highest velocity cannon that could fit? Country of origin for cannon doesn't matter. The 37mm Oldsmobile cannon was very low velocity, so, I am wondering about a high velocity weapon. I am guessing it would be some sort of German cannon.
     
  2. Aaron Brooks Wolters

    Aaron Brooks Wolters Well-Known Member

    Joined:
    Jul 28, 2007
    Messages:
    15,719
    Likes Received:
    339
    Trophy Points:
    83
    Gender:
    Male
    Occupation:
    Auto Restoration
    Location:
    Abingdon, VA.
    Just going off what I think I remember reading so I could be wrong but I think they started out with a 23mm cannon and then went to the 20mm. I don't think you could get to much bigger without running into problems.
     
  3. pinsog

    pinsog Member

    Joined:
    Jan 20, 2008
    Messages:
    658
    Likes Received:
    15
    Trophy Points:
    18
    So, in your opinion, a German 30mm cannon wouldn't fit? We already had a low velicity 37 mm cannon installed.
     
  4. Aaron Brooks Wolters

    Aaron Brooks Wolters Well-Known Member

    Joined:
    Jul 28, 2007
    Messages:
    15,719
    Likes Received:
    339
    Trophy Points:
    83
    Gender:
    Male
    Occupation:
    Auto Restoration
    Location:
    Abingdon, VA.
    It may be that the cyclic rate was to slow for aerial combat. I would tend to think that the 20 or 23mm would give a better CG than the 37 though, plus with the smaller cannons you could carry more ammo, but I am a little out of my league here and am probably wasting your time. There are guys here who know volumes more than I do about it.
     
  5. vanir

    vanir Banned

    Joined:
    Jul 22, 2005
    Messages:
    705
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Melbourne
    #5 vanir, Dec 11, 2011
    Last edited: Dec 11, 2011
    They were designed for the Oldsmobile gun. It's a gigantic gun. You could get something like a 5cm FlaK in the space of that gun, shortened and lightened of course. That'll do most tanks.
    P-38 is the same here, also meant to receive the Oldsmobile but early in production license made Hispano were standardised.

    Neither would be very stable firing such a monster. You want a light bomber for it really.

    For Soviet operators an NS-37 or dump all the nose guns for twin 23mm and a ton of ammo would be good.
     
  6. pinsog

    pinsog Member

    Joined:
    Jan 20, 2008
    Messages:
    658
    Likes Received:
    15
    Trophy Points:
    18
    What is the performance of the NS-37? I guess you mean syncronise 2 23mm cannon and fire through the prop arc?
     
  7. riacrato

    riacrato Member

    Joined:
    Oct 17, 2009
    Messages:
    669
    Likes Received:
    4
    Trophy Points:
    18
    Occupation:
    Project Manager in FADEC industrialization
    #7 riacrato, Dec 12, 2011
    Last edited: Dec 12, 2011
    I think there was a drawing showing the various WW2-era cannons on Tony Williams site. It would help for size comparison. My personal opinion::
    - MK108 should fit easily, with lots of ammo, too.
    - MK103 should fit and would probably be the most powerful of the German mainstream guns. Maybe even the MG213 or one of the experimental German 50mm cannons could be fitted but they're too late to qualify. Maybe even the BK 37 would fit, but probably not.
    - NS37 should fit as well, nominally this would probably be the most powerful cannon available mid-war.
     
  8. vanir

    vanir Banned

    Joined:
    Jul 22, 2005
    Messages:
    705
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Melbourne
    The Bofors and BK.5cm fit inside that nose bay of an Me-210/410, they just had to run the breech under the cockpit floor, but provided a panel for the gunner to reload clips iirc. Have a look at the cutaway of that installation, I think it would replace the oldsmobile gun just fine. Heavier but not really bigger, and that'll help recoil anyway. You'll want some sort of suspension system with that heavy a gun though in a small fighter, plane's too light. NS45 was too heavy for a Yak despite being capable of being mounted physically no problem. Now that's some gun. Yaks aren't very big.

    Yeah I meant synchronise the 23mm, shouldn't be any harder than a 2cm the case is small and it's good for bombers and soft targets. The NS37 was claimed by the Soviets to be good against Panzer III and IV upper and rear armour, it was designed to take them out. Pilots often used them in air to air but it's an anti-armour high velocity gun with a very big bang.
     
  9. michaelmaltby

    michaelmaltby Well-Known Member

    Joined:
    Jan 22, 2009
    Messages:
    3,874
    Likes Received:
    576
    Trophy Points:
    113
    Gender:
    Male
    Location:
    Toronto
    [Wikipedia]

    "..... This happened because H.M. Poyer, designer for project leader Robert Woods, was impressed by the power of this weapon and he pressed for its incorporation though the original concept had been a 20–25 mm (.79–98 in) cannon mounted conventionally in the nose. "
     

    Attached Files:

  10. Shortround6

    Shortround6 Well-Known Member

    Joined:
    Jun 29, 2009
    Messages:
    9,761
    Likes Received:
    793
    Trophy Points:
    113
    Occupation:
    retired Firefighter
    Location:
    Central Florida Highlands
    Is there a time frame on this?

    Or a reason for wanting a different gun?

    Most of the really big stuff didn't cycle any fast than the 37mm M4 and so weren't much better for air to air.

    By the end of the war the US had the M9 cannon using a much more powerful cartridge (same one as the 37mm tank/AT guns).
     
  11. vanir

    vanir Banned

    Joined:
    Jul 22, 2005
    Messages:
    705
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Melbourne
    You're good at this Shortround6, given an open cheque and no time worries (your lab is in an interdimensional space), what would you use?
     
  12. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,988
    Likes Received:
    432
    Trophy Points:
    83
    M4/M10 were really small guns for 37mm calibre, being at the lower end of MV an RoF for that category. A comparison vs. 5 cm flak leads to nowhere - M4 was just a tad longer than 2m, while even the Flak 3,7cm was already at 3m.

    Yep, NS-37 seem like a winner for this thread.

    250-350 rds per minute, 735 g shell weight fired at 900 ms.

    All fine choices; the experimental 5cm were quite bulky though.

    The 5cm was big brute, about a meter high at the rear end; it's receiver, recoil loading mechanism was 1,5 metre long. I doubt that it would've fitted inside.
    As for what NS-37 was suposed to do, that depends on a plane it was mounted to. In IL-2s, it was to kill tanks. In Yak-9T/UT, it was to kill other planes - as stated in 'Soviet combat aircraft' book by Gordon Khazanov.
     
  13. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,988
    Likes Received:
    432
    Trophy Points:
    83
    Hmm, too bad they didn't pushed for 28mm. But, being a 'Navy round', guess that would've been considered as blasphemy ;)
     
  14. vanir

    vanir Banned

    Joined:
    Jul 22, 2005
    Messages:
    705
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Melbourne
    I believe it is on record that pilots wound up using them mostly in air to air, but the T designation, Yak-9T, look it up. Same with K (NS45). Antitank version according to TsAGI. Aero gun according to pilots well fair enough, but that wasn't its intended specification. IL2 escorts were attached to ShAP directly, they weren't part of the IAP. They were supposed to escort with primary support tasking (if no fighters encountered, engage ground targets alongside sturmoviks). Instead the pilots would run off and look for German fighters if none were present. The test in Ukraine of the Yak-9K is recorded somewhere, someone at an IL2 game site posted it once so there's a whole writeup on how both the Yak-9T and K were supposed to be used in wartime docs. Game designers mention it in passing too, in the game itself, they've got more direct access to scant soviet records than me.

    Problem with soviet wartimes records is they are scant indeed, many were destroyed for political censorship and the surviving ones are often extremely general and sweeping in nature, for example specific records only down to the battalion level at best. German records go into detail down to the squad level. Hard building accurate pictures of the soviet situation.

    You could be right tomo, in other words.

    You should really check out the Hungarian bofors in the little Me-210 weapons bay though. Bofors is big. Germans put BK5 in them. Russians put NS45 in Yaks. You're really going to tell me they won't physically go into the airacobra? I think they will, I think you just won't be able to fly the plane well or fire them accurately.
     
  15. tomo pauk

    tomo pauk Creator of Interesting Threads

    Joined:
    Apr 3, 2008
    Messages:
    7,988
    Likes Received:
    432
    Trophy Points:
    83
    The 'T' from Yak-9T comes from 'tyazhelo vooruzheny' - 'heavily armed'.
    The 'K' comes from 'krupnoy kalibrovy' - 'of big calibre'. The NS-45 was to NS-37 what MG-151/20 was to MG-151. The cartridge case was necked out shortened, featuring a shell from ground-based 45mm guns. It was notably smaller than Flak 3,7, or about as big as Vickers Class 's' gun from Hurri IID (but with slightly longer barrel - not an issue here). That also means it's smaller than Bofors 40mm.

    A initial usage of the NS-37 was in fighter units, in LaGG-3-37 planes. The Gordon Khazanov book mentions 42nd Air Fighter regiment (or IAP) as the 1st unit to use them, then 291th IAP, near Stalingrad. The commander of a Air Fighter Division, that 291th was part of, claims that such planes were powerfull and effective vs. enemy bombers. The 240th IAP is mentioned in the Yak-9T article. During the Kursk battle, it was noted that it took 32 expanded rounds per enemy A/C killed.

    But I can see that VVS would use Yak-9Ts in an 'oportunistic' way - attacking what ever target is in sight, even if that target is a plane and they had, for the sortie, only AP ammo on board.
     
  16. Shortround6

    Shortround6 Well-Known Member

    Joined:
    Jun 29, 2009
    Messages:
    9,761
    Likes Received:
    793
    Trophy Points:
    113
    Occupation:
    retired Firefighter
    Location:
    Central Florida Highlands
    I like to keep thing simple, just use the American M9 cannon, while weighed almost double what the M4 did it had the same rate of fire and use some of the same projectiles. The bigger cartridge case meant that the velocity for the HE shell went from 610m/sec to 800m/sec and the AP shot went from 556m/sec to 930m/sec?
    I am not sure how much more power is needed? This is the same power "class" as the 37mm guns slung under the wings of the JU-87 and is more powerful than the Russian N-37 even if slower firing.
    The M9 weighed 181kg vs the 400-500kg of the German or Hungarian 50mm and 40mm guns.
     
  17. vikingBerserker

    vikingBerserker Well-Known Member

    Joined:
    Apr 10, 2009
    Messages:
    24,064
    Likes Received:
    655
    Trophy Points:
    113
    Occupation:
    Korporate Kontrolleur
    Location:
    South Carolina
    That would leave a mark!
     
  18. davebender

    davebender Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    6,418
    Likes Received:
    64
    Trophy Points:
    48
    Location:
    Michigan, USA
    What are you planning to shoot at? For ground attack vs tanks you need armor penetration. For attacks against aircraft and soft ground targets you want HE filler. For all around performance I would pick the German 3cm Mk103 cannon. Highly effective against both ground and aerial targets.
     
  19. Aaron Brooks Wolters

    Aaron Brooks Wolters Well-Known Member

    Joined:
    Jul 28, 2007
    Messages:
    15,719
    Likes Received:
    339
    Trophy Points:
    83
    Gender:
    Male
    Occupation:
    Auto Restoration
    Location:
    Abingdon, VA.
    That's putting it mildly.
     
  20. vanir

    vanir Banned

    Joined:
    Jul 22, 2005
    Messages:
    705
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Melbourne
    Well that's good enough for me. M9 it is. I didn't really know there was a difference like that between the M4 (or T9 was it also called?) and the later M9. I just assumed ROF probably went up like with the BMG fifties.
    Well that's a lot of punch for not bad weight. That's about the same weight as an MK103 too isn't it? So either one of those two then I'd say, or the NS37. Given the M9 was adopted, once again it appears that history happened its way as best it could've.
     
Loading...

Share This Page