20mm rear/tail gun: did it made any difference?

Discussion in 'Aviation' started by tomo pauk, Mar 28, 2012.

  1. tomo pauk

    tomo pauk Creator of Interesting Threads

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    ... compared with 1-2 HMGs, or 2-4 LMGs? Some French bombers have had it installed; maybe German? Please, post your findings/data :)
     
  2. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    I was told by an old neighbor who was a B-17 F/E (Top Turret) that the tail gunner had the best chances of shooting down an opponent, but also had a bad survival rate (obvious reasons). I don't think it would be the size of the gun but rather the effectiveness and reliability of it at the tail position.
     
  3. model299

    model299 Member

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    #3 model299, Mar 28, 2012
    Last edited: Mar 28, 2012
  4. model299

    model299 Member

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    The original B-17 tail turret was a cramped affair, with limited gun travel and smallish windows. The later Cheyenne turret offered more room, greater visibility, and much improved gun travel. A (Since deceased. RIP Gail!) neighbor of mine from my old neighborhood who served as radioman told me that the gunner in their plane preferred to ride in the waist during takeoff and formation. The pilot would lower the tail wheel when asked so he could crawl back to his station when they approached the channel. He said the guy didn't like riding back there during takeoff and climb out as the bouncy ride made him nauseous. Their pilot eventually became group leader, (With about 10 missions left in their tour, IIRC.) and the tail gunner was forced to get in the turret before takeoff to keep the pilot informed as to the group's disposition during formation. He was forced to keep a bucket with him, and used it often. He would also line the floor of his station with flak jackets in an effort to ward off flak bursts and bullets from below. He “nicked” a few German fighters, and claimed one probable.
     
  5. Juha

    Juha Well-Known Member

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    #5 Juha, Mar 28, 2012
    Last edited: Mar 28, 2012
    Now what I recall
    the rear 20mm gun in H6K Mavis and in G4M Betty was effective against US fighters attacking directly behind, like when USS Lexington tried to raid Rabaul in Feb 42. Or during the first combat between Bettys and Lightnings over Aleutians. But the firing sectors of those Japanese guns were narrow and by using deflection shooting Japanese bombers like Betty and Ki-49 Helen and Mavis became fairly easy targets to Allied fighters. So 20mm tail gun alone didn't give good protection but made the easiest attack line, from dead astern, risky. Was they markedly more effective than mgs, now other gun positions in Mavis, early Bettys and Ki-49s were armed with single lmgs and Allied fighter pilots found them fairly ineffective but on the other hand the F4F shot down by a Mavis during the Lex operation in Feb 42 was hit into the unarmoured windscreen so even lmg bullet(s) might well have done the job. The junior USN pilot simply used wrong attack tactic even if instructed against using it.

    Juha
     
  6. tyrodtom

    tyrodtom Well-Known Member

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    Most 20mm guns i've seen have pretty massive breeches on them, if they're installed in a turret like most tail turrets, you're gonna up up with very little traverse, because you've got very little room in the tail to swing that breech around in.

    Unless it had a tail turret like a Landcaster, or B-24, then it would have to be a very large diameter, and sturdy turret to fit a 20mm . I think some varients of the He177 had a 20mm dorsal turret.
     
  7. davebender

    davebender Well-Known Member

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    Primary purpose of a tail gunner is to force enemy fighter aircraft to break off or at least screw up their aim. That allows the bomber to survive and (maybe) continue its mission. Shooting the enemy down is not necessary. It's just a bonus.

    A fighter pilot would need nerves of steel to ignore rounds pelting his aircraft. So IMO the best way to deter an enemy fighter aircraft is to land some hits on his aircraft even if they aren't fatal. High rate of fire and high velocity (in that order) provide the best chance to score hits.

    By 1941 most aircraft were relatively well protected against .30cal projectiles. .50cal / 13mm is probably the minimum effective size. So any fast firing weapon at least .50cal in size should work for a bomber defensive gun.
     
  8. Jerry W. Loper

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    Hits from a 20-mm. tail gun would've been devastating to a fighter approaching from the bomber's 6 o'clock. Trouble is, since the rate of closure from the rear was slower than any other aspect, smart fighter pilots preferred headon or beam attacks.
     
  9. Tante Ju

    Tante Ju Banned

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    Pilots I read often did not even notice the hits until the engine started to act funny. On the other hand, the hail of tracers did large pschylogie effect.
     
  10. davebender

    davebender Well-Known Member

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    #10 davebender, Mar 29, 2012
    Last edited: Mar 29, 2012
    IMO the Me-210 got this about perfect. A pair of remote control barbettes. Each contained a 13mm MG firing @ 900 rpm. 1,800 rpm for both weapons. The gunner sits in the armored cockpit section.
    04-barbette1.JPG
     
  11. razor1uk

    razor1uk Well-Known Member

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    #11 razor1uk, Mar 29, 2012
    Last edited: Mar 29, 2012
    I hazzard to think that if the fire is coming towards you, it'd be most improbable that you'd see the tracers glowing... even if the muzzle-flash was negligable.
     
  12. tyrodtom

    tyrodtom Well-Known Member

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    How many aircraft did these perfect guns shoot down ?
     
  13. razor1uk

    razor1uk Well-Known Member

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    #13 razor1uk, Mar 29, 2012
    Last edited: Mar 29, 2012
    Certainly not as many as they wounded/damaged - I'd guesstimate the RHAF could/would-'ve had better statistics for this (assuming the info survived the Soviet era) since they liked it more than the 'Waffe.
     
  14. davebender

    davebender Well-Known Member

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    Exactly what a tail gun is supposed to do. Force the enemy fighter to break off his attack.
     
  15. beaupower32

    beaupower32 Well-Known Member

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    Thats what she said.....:D

    Intresting thread, thanks for posting....
     
  16. Capt. Vick

    Capt. Vick Well-Known Member

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    I think you maybe thinking of the Ju 188.
     
  17. drgondog

    drgondog Well-Known Member

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    I'm pretty sure Tyrodtom is correct.

    Two of the obvious reasons a tail gun position Should be more effective... one, the rate of closure/relative airspeeds between the gunner and the closing fighter is at the minimum, and two, the deflection angles are also at a minimum - taking deflection out of the equation. For a B-17 the Cheyenne turret also added some incremental rigidity as a gun platform and the computing gunsight also increased its capability - ditto B-29.
     
  18. Juha

    Juha Well-Known Member

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    Vick is correct
    188 had 20mm cannon in its dorsal turret, He 177 had it in its rear position, its dorsal turret(s) had 13mm MG 131s, both 188 and 177 had also a forward firing 20mm cannon.

    Juha
     
  19. drgondog

    drgondog Well-Known Member

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    Juha/Vick - I stand corrected.
     
  20. tyrodtom

    tyrodtom Well-Known Member

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    I don't think most pilots, i'm talking in particular the Luftwaffe pilots, were overly worried about the individual turrets in any one bomber. Once they had a straggler separated from the rest of the formation, it was usually not long for this world.

    But when formations were tight, they had to content with a gauntlet of fire, gunners shooting at them from all directions.
    Once a fighter would concentrate on one bomber, and was heading for one gunners position, that fire would be just as potentially distracting for that gunner as the fighter pilot. But the fighter has a lot more guns, and usually better armor too.
     
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