Vulnerability of liquid cooled engines

Discussion in 'Aviation' started by Jenisch, Apr 2, 2013.

  1. Jenisch

    Jenisch Active Member

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    #1 Jenisch, Apr 2, 2013
    Last edited: Apr 2, 2013
    Hello,

    Liquid cooled engines have a popular fame of being vulnerable. In the case of the P-51, this is well know. However it's practically not mentioned in the case of other acft like the Spit, 109 and Yak. And perhaps what is most curious: the IL-2 used a liquid cooled engine.

    I'm wondering at which point such "vulnerability" is a myth or not...
     
  2. tyrodtom

    tyrodtom Well-Known Member

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    Look at a cutaway of a IL-2, and you'll see lots of armor of various thickness covering all the important points.
    A good example is the coolant radiator, it has a air intake in front of the cockpit, that then goes down to below the floor to the radiator itself buried in the middle of the fuselage, protected on all sides by armor.
     
  3. CobberKane

    CobberKane Banned

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    there was a pretty comprehensive thread on this forum a while back concerning the relative durability of radial v inline engines. One body of thought held that the difference between was overstated, the other was that the weight of anecdotal evidence and pilot opinion was right and the radial engines were much more battle resistant. Personally I'm in the latter camp. There are just too many accounts of radial engine fighters returning with massive engine damage, and as many of inline engines stopped by minor hits to the cooling system
     
  4. Shortround6

    Shortround6 Well-Known Member

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    Comparing a protected engine/radiator like an IL-2 to a naked engine installation isn't quite fair unless you count the the weight of the protection (armor) as part of the powerplant.

    Some radials had partially armored cowling and or armored oil coolers. We start arguing about the amount of protection each engine had instead of the engines themselves.
     
  5. Balljoint

    Balljoint Member

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    While not statistically sound, the film of the navy fighter –probably a Hellcat- still on the arresting cable with white hot metal gushing from the engine cowling makes a strong case.
     
  6. Ainene

    Ainene New Member

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    P-51 is obviously getting compared with other American fighters.
    But comparing with lighter European fighters... 3 fighters you mentioned(spit, bf-109, yak) - all were among easier ones to shoot down(damage-absorbing ability wise).
    And Il-2 is very good example: how heavily armoured craft's survivability may be lowered thanks to water-cooled engine, with radiator(underbelly) damage among the most stable loss reasons.
    example:
    from soviet Il-2 pilot interview:
    Google translation(fixed it a bit)
     
  7. dobbie

    dobbie Member

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    Unless there is armor applied, the liquid cooled engine is going to be more vulnerable than an air cooled engine simply because of the fact that the radiator and the piping present more area. And with an air cooled engine, less armor would be needed to protect it because you have less mass to cover.
     
  8. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Thanks for posting the excerpt.
    The radiator at underbelly was oil cooler, the water-glycol cooler being well protected in the tunnel shaped like shallow S letter. The experienced LW fighter pilot would try to sneak under and give it a burst or more; the experienced Stormovik pilot will of course try to deny that opportunity. Those less experienced being majority, however.
     
  9. davebender

    davebender Well-Known Member

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    Liquid cooled engine block is probably tougher then an air cooled engine.

    Wing mounted radiators and associated piping are the real problem. An easy way to place the heavy cooling system over aircraft center of gravity but fatal if aircraft gets shot in the wing.
     
  10. davebender

    davebender Well-Known Member

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    Why go to that trouble if you have 20mm cannon with decent HE shells? Just rip big holes in the unarmored wings.
     
  11. drgondog

    drgondog Well-Known Member

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    A challenge for the statistics hounds is to narrow the data to relevant 'packages'

    What was the threat envirionment?

    What was the probabilty of a fatal hit at the altitude, speed and time acquired as a target?

    How many times was the subject aircraft/powerplant exposed to a high threat environment?

    What is the % of defined and verifiable losses?

    Any set of data that anybody is aware of that address these discrimants?
     
  12. Ainene

    Ainene New Member

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    Another hint:
    (soviet statistics)
    More then 20% damaged craft had damage to wings, but only 3% to oil cooler. Of aircraft that made it back(i.e. landed safely/crash-landed on field),not shoot down.
    Il-2 was quite resistant to simple holes, and control wires in the wings were reserved. It is possible, but for this kind of kill better shoot tail(here control can be denied by single lucky shell,and tail control surfaces much simpler to rip off anyway).
     
  13. davebender

    davebender Well-Known Member

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    MG151/20 fired 750rpm and 20mm mine shells contained 18 grams of HE. Why wouldn't you hit IL2 wing with several shells, each of which punches a 1 foot or larger hole? Single hit might not be fatal but 5 probably will be.
     
  14. GregP

    GregP Well-Known Member

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    Regarding post # 11 Drgondog, as an engineer, it has always been my contention that if you don’t save the data, there is virtually no chance of using it to discover how to best improve the process. I have always wanted to save the data once avionics became good, and use it to analyze missions for potential improvement. For instance, with today’s avionics, it should be possible to know how many bullets/missiles. Etc. were shot, at what speed, at what power level, at what attitude and rate of climb or descent, at what angle, the g-load, and the relative coordination of the turn and bank indicator.

    Even in WWII, it should have been possible to install bullet counters and have gun cameras on most WWII fighters. The fact that we didn’t pay attention to these data mean the sum total of the biggest aerial war in history is difficult or impossible to analyze correctly since the available data are so inconsistent in their availability and are largely totally missing.

    There is almost no excuse in modern warfare. The measn to record such things are light, relatively inexpensive relative to the rest of the aircraft, and would simplify analysis in all encounters.
     
  15. tyrodtom

    tyrodtom Well-Known Member

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    I remember in Hartmanns book he mentioned aiming for the oil cooler, as being his favorite way of bring down the IL-2.
    The wings from behind are not a very big target, and if the other aircraft is manuvering, they're always changing position relative to you, while the fuselage will be in a more constant position as you mannuver with the other aircraft.
     
  16. Ascent

    Ascent Member

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    The Mosquito and Beaufighter were both used in the anti shipping role, often on the same missions. Both are twin engined ,one is liquid cooled, the other air.

    Do we have any direct comparison about engine survivability between the two?
     
  17. davebender

    davebender Well-Known Member

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    Experts such as Hartmann can aim for the relatively small oil cooler. Normal pilots aim for center of mass and are lucky to land a burst on target.
     
  18. R Pope

    R Pope Member

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    A bullet in the rad would be much more serious in a Mustang over Berlin than say a Spitfire over
    London.......
     
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  19. Jenisch

    Jenisch Active Member

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    Dont know if started in specific model, but the 109 could fly with a radiator out.
     
  20. Shortround6

    Shortround6 Well-Known Member

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    Only specifically equipped aircraft of certain models.
     
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