In-Vulnerable Fortresses?

Discussion in 'Aviation' started by muskeg13, Nov 25, 2014.

  1. muskeg13

    muskeg13 Member

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    How vulnerable were early model B-17s (C-Fs) in the Pacific when flying at 20-30K feet? While they may not be able to hit anything, when flying at top speed at altitude, couldn't they outrun Zeros? If so, they could be useful for reconnaissance and harassment.
     
  2. GrauGeist

    GrauGeist Well-Known Member

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    There was a recon version of the B-17: the F-9, F-9A/B/C and the top speed of the B-17 was 287mph (462kph). The A6M2 had a top speed of 332mph (534.3kph) and would be able to catch it easily.

    Also, the ceiling of the B-17 was about 35,000 feet and the Zero's was about 33,000 feet.
     
  3. muskeg13

    muskeg13 Member

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    #3 muskeg13, Nov 25, 2014
    Last edited: Nov 25, 2014
    The C-F model B-17s were considerably faster, and they had higher service ceilings. You're quoting G Model specs. Plus the Zero's max speed was at 14,930'
    B-17C 323mph at 25,000', ceiling 37,000'
    B-17D 323mph at 25,000', ceiling 37,000'
    B-17E 317mph at 25,000', ceiling 36,000'
    B-17F 325mph at 25,000', ceiling 37,500'

    I think the early model B-17s may have been better performers than the Zero above 20,000'
     
  4. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    I show a Model 21 Zero with a top speed of just over 330 mph at almost 15,000 feet and a service ceiling of 33,000 feet. I doubt you'll see 330 mph in this mark of Zero above 30,000 feet and more than likely an early model B-17 at altitude would be just as fast if not faster than a Zero.
     
  5. Glider

    Glider Well-Known Member

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    I think its worth remembering that the RAF B17C had a very difficult time in Europe and they had a lot of performance problems at very high altitude. IIRC it was the USAAF advisors in Britain recommending that the RAF should not use them in action as they were not ready.
    So the headline performance numbers for the B17C may be one thing but in the real world they were very different.
     
  6. oldcrowcv63

    oldcrowcv63 Well-Known Member

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    #6 oldcrowcv63, Nov 25, 2014
    Last edited: Nov 25, 2014
    Factsheets : Boeing B-17C

    provides a maximum speed of 323 mph at 25k' for the 'C' model.

    Without knowing the details, I'd expect the raw performance of the B-17C wasn't so much of an issue as an evident need to make other combat-readiness modifications.

    Wikipedia entry does seem to be generally consistent with your post:

    List of Boeing B-17 Flying Fortress variants - Wikipedia, the free encyclopedia

    "With the passage of the Lend-lease Act in 1941, the Royal Air Force began clamoring[citation needed] for use of the B-17. At that time, the Army Air Corps was suffering from shortages of the B-17, but [hesitantly] agreed to provide 20 planes to the RAF. Though the Army Air Corps did not consider the B-17C ready for combat, it was desperately needed in Britain. They were modified Boeing production B-17C, given the company designation Model 299T. The modifications were the addition of self-sealing tanks and replacement of the single nose gun with 0.5 inch Brownings.[1]

    The twenty planes were placed immediately into frontline service as the Fortress Mk I.

    In Britain, the plane performed unremarkably. By 1941 September, 39 sorties had made up 22 missions. Nearly half of the sorties were aborted due to mechanical problems. Eight of the twenty were destroyed by September, half to accidents. Their guns tended to freeze at high altitude and were generally unable to effectively protect the Fortresses. Their success as a bomber was also limited, largely because they were unable to hit anything from the altitudes at which they flew.

    The first "C" series flew in July 1940; 38 were built. The eighteen remaining after twenty were transferred to the RAF were modified to the configuration used in the B-17D. However, one of these, B-17C 40-2047, crashed while being ferried from Salt Lake City, UT, to Mather Army Air Base, CA, on November 2, 1941.
    "

    I'd expect the D model might have been able to outrun the zeke at hi-altitude but lessons learned in RAF European service suggests (as above) may have meant they would fly operationally only at Zero accessible altitude. There are references in the literature citing successful IJN attacks on B-17D (and the more modified E's, although I have none at hand at the moment).
     
  7. davebender

    davebender Well-Known Member

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    That suggests no bomb load and minimal fuel load. Hardly typical combat conditions.

    Economical cruise speed with typical bomb load is what counts.
     
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  8. oldcrowcv63

    oldcrowcv63 Well-Known Member

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    #8 oldcrowcv63, Nov 25, 2014
    Last edited: Nov 25, 2014
    Yep. Good point.
     
  9. GrauGeist

    GrauGeist Well-Known Member

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    My figures I put up were for quick comparison, but perhaps I should have expanded on that more.

    No matter what you do, the B-17 is not going to be well suited to a "high speed" recon role. It was used in the recon role under the F-9 series, as I mentioned before. There were both armed and unarmed versions. It can go without saying that the unarmed versions would be typically faster, but even still, not immune to interception. Also keep in mind that the Japanese weren't just flying A6M series aircraft, they had much faster and higher climbing aircraft in their inventory toward the latter stages of the war.

    Even the fastest of the fast recon aircraft (Ar234, F-5 Lightning, Mosquito, etc) were liable to interception.
     
  10. GregP

    GregP Well-Known Member

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    #10 GregP, Nov 26, 2014
    Last edited: Nov 26, 2014
    The question was about C's and F's. These were early models and were probably very GOOD candidates for photo-recon at high altitudes and high speeds in the Pacific. Perhaps not so much if not ina photo-recon mode since it would THEN have a bomb load and maybe be lower and slower.

    Later models would have been slightly slower or not if the guns were reduced. The Allison-powered XB-38 weas faster than the radial version, but not much so. Basically it was hovering slightly above or slightly below 300 mph. Maybe 285 for the bombers and maybe 315 for a photo-recce version.

    That's maximum speed. It would have been quite possible to extract a bit more speed, but not enough to outrun the faster fightersm so remoiving armament was not something the military service would have wanted. After all, the B-17 DID have 10 guys in there that were trained rather expensively.

    As we saw in service, the B-29 coming in at 350 mph was fairly immune to interception if at higher altitudes. If they came in lower, which they DID to gain accuracy, they were more vulnerable to interception. I did a spreadhseet in the past on a 380 mph Japanese fighter trying to make a head-on pass and then turn around and re-attack a 350 mph B-29. It was not possible or barely possible depinding on the fuel situation, and the rate of closure would have made the pursuing fighter very vulnerable to the tail gunner. If the enemy is closing at 20 - 30 mph, he is relative "meat on the table" to any decent gunner. If the B-29 was goiong 350 mph and nosed over ina shallow dive, which they DID, to gain more mspeed, it was going 370 - 380 mph and interception was impossible after the first head-on pass, assuming the Japanese fighter could get as high as the B-29 in time to shoot at it.

    All that assumed the fighter could pull about 2.5 - 3.0 g in a reltively level turn at high altitude and not loose too much speed, and that may or may not have been the case. At 25,000+ feet, maybe the figher could only pull 1.5 g or so before losing too much speed or getting close to stall.

    This thread has possibilities, but not really for the B-17 except maybe as a photo-recce early in the war, when flown fast, high and light.
     
  11. GrauGeist

    GrauGeist Well-Known Member

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    In response to:
    I referred to the F-9 and F-9A/F-9B

    The F-9, F-9A, F-9B and F-9C were B-17 aircraft converted to recon/photo-recon configurations. All the F-9s were converted from early type B-17, except for the F-9C, which was based on the B-17G.

    Other comparable types would be:
    F-2 series: C-45
    F-3 series: A-20
    F-7 series: B-24
    F-10 series: B-25
    F-13 series: B-29
     
  12. Glider

    Glider Well-Known Member

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    I am in the process of moving house so everything is in box's but the book I had in mind had a complete chapter on the early B17 in RAF service and the list of problems IIRC was a lot longer than outlined in Wiki
     
  13. oldcrowcv63

    oldcrowcv63 Well-Known Member

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    Given that "nearly half of the sorties were aborted due to [unspecified] mechanical problems." I wouldn't be at all surprised.
     
  14. Graeme

    Graeme Well-Known Member

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    I remember reading as a kid the "ventral bath" was a death trap. However it was in a Commando Comic so I'm not sure if it was a reliable source. :)

    However this is probably a little more reliable, a 1943 aircraft recognition manual that suggests if the C model couldn't outrun the fighters, they were "dealt hardly with."

    [​IMG]
     
  15. GregP

    GregP Well-Known Member

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    The questiuon was about early model B-17's (C-F's), not conversions to other designations.

    I wasn't referring to any C's or F's other than the B-17C and B-17F as the poster asked about.
     
  16. GrauGeist

    GrauGeist Well-Known Member

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    Greg, muskeg13 asked if the B-17 would make a good recon platform...and I said it had been done: the F-9

    The B-17G recon version was the F-9C, the F-9, F-9A/B were the earlier types.

    So instead of them wondering if a B-17 would make a good recon platform, my reference to the F-9 informs muskeg13 that it had been done.
     
  17. muskeg13

    muskeg13 Member

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    No, my question was... "How vulnerable were early model B-17s (C-Fs) in the Pacific when flying at 20-30K feet?" I believe the correct answer is: fairly invunerable, particularly with the E and F models. Japanese fighters/interceptors struggled at that altitude to keep up and defeat well defended and relatively fast heavy bombers. My intent, is to dispell the myth of early war Japanese aircraft invincibility and postulate that the Philippine-based USFAF B-17s could have dealt a decisive blow if they were not allowed to be destroyed on the ground.
     
  18. GrauGeist

    GrauGeist Well-Known Member

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    But the Japanese aircraft were very capable of intercepting the B-17 at operating altitudes early on the war...and they did.

    It wasn't just the A6M that the B-17 crews (and others) had to worry about, there was the KI-43, KI-45, KI-46, J2M and others.
     
  19. Milosh

    Milosh Well-Known Member

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    Don't think the 2 12.7mm mgs of the Ki-43 would be that effective in shooting down recon B-17s.
     
  20. oldcrowcv63

    oldcrowcv63 Well-Known Member

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    #20 oldcrowcv63, Nov 29, 2014
    Last edited: Nov 29, 2014
    The oft quoted complete destruction of the USAAF grounded air force in the PI is a (perhaps face-saving?) overstatement. Half survived the initial assault and made little to no difference in the outcome. Had the full complement of 30+ B-17s been preserved, events suggest they wouldn't have made a significant difference. B-17 was the wrong airplane for defense of the PI and was according to much recent literature, a paper tiger to deter war in the Pacific. Some analysis suggests its presence in the PI prematurely precipitated the Pacific war.

    Flying lots of recon missions where the B-17 may be least vulnerable will do little to diminish or forestall the IJN IJA's assaulting forces. As has been pointed out, Loaded with bombs and defensive ammo will considerably reduce the A/C's performance putting it within easy reach of the high-flying A6M which was dominant in the Pacific to a degree not seen in Europe. In other words. IJN air control was no myth. Allied aircraft were too few in numbers, applied tactically incorrectly and largely outclassed with few exceptions. (primarily Chennault's crew in mainland and Indo- China vs the IJA's Ki-43 and other non-A6M types)
     
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