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Radial aircraft engine survival.

Discussion in 'Aircraft' started by gtblackwell, May 22, 2010.

  1. gtblackwell

    gtblackwell Well-Known Member Patron  

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    I have read more than a few accounts of a radial losing a cylinder , off the block, and continuing to fly. Stories are sometinmes related to P-47's. I am not an engineer but is this even possible. The piston and connecting rod would try to rotate and would either jamb the block or break off themselves, then the engine would go out of balance and lose oil would it not ? I would love to here verified accounts of this happening. It is possible for it to shear off all the extraneous parts and continue to make power?

    GB
     
  2. Sentinel

    Sentinel Member

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    I've heard stories of this happening, too. If only one of the cylinder heads was shot off, the piston and oil would still be safe, though the cylinder wouldn't deliver any power. However, if an inline engine lost a chunk of cylinder head, it would soon lose all its coolant and overheat. That is one plausible explanation.
     
  3. brndirt1

    brndirt1 Saddle Tramp

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    The part one must remember is that each piston has its own "jug" inside of which it operates, and the connecting rod is VERY short. Without the "jug" itself the piston will disappear (it is aluminum), and the connecting rod will just "clatter" around inside of its short stroke.

    If a single "jug" is blown off, it isn't impossible for the engine to continue to operate (roughly) since they hold no oil in a sump like a V or inline water-cooled. The oil is contained in a tank and supplied to the parts by a pressure pump. They won't loose their cooling ability, they won't loose their lubrication ability (for a time), and they will only loose the power of that particular cylinder and piston.

    They will "spray" oil out of the lost section (but more of a mist than a stream), but they have a multiple gallon tank they draw upon. Only the loss of the scavanging portion of that single power cylinder will "loose oil", and there is no place for parts to accumulate and clog oil galleries.
     
  4. T. A. Gardner

    T. A. Gardner Genuine Chief

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    Yes, this thing is possible. Now, while not an aircraft engine, I have seen some of the old Volkswagen / Porsche air cooled engines running in absurd, nightmare (to a mechanic) condition. I have a friend that owned a 'bug' some years ago. This vehicle was driven from Phoenix AZ to Tucson and for sometime thereafter with a broken crankshaft that allowed only the two forward cylinders to operate. The rings were so deteriorated that they crumbled when taken out.
    Air cooled engines and, old piston engines are incredibly tough. They were over-engineered in terms of the materials that went in, tolerances were sloppy enough to make up for wear and tear and, the engineers that designed them left alot of slack in the design that could make up for damage and wear.
     
  5. formerjughead

    formerjughead The Cooler King

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    A radial engine is the ultimate in redundancy. Very simlpe to operate and maintain and incedibly durable.
     
  6. gtblackwell

    gtblackwell Well-Known Member Patron  

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    Thanks , fellows, if the short stroke keeps the connecting rod in the clyinder and the piston broke off it seems feasible.
    Would love to find a verified case but not a huge issue. Great place to learn.....GB
     
  7. brndirt1

    brndirt1 Saddle Tramp

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    This animation may reveal why the radial is so robust as compared to an inline water-cooled engine.

    YouTube - Autodesk Inventor - Radial Engine

    There is another one in that mix, but I liked this one best. Notice how independent each cylinder is from the others in the system.

    Here is the other:

    http://www.youtube.com/watch?v=iZqV_4A4bI8&feature=related
     
  8. mcoffee

    mcoffee Son-of-a-Gun(ner)

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    I'll have to look for the source (probably Barrett Tillman's "Hellcat: The F6F in WWII"), but I seem to remember reading an account of David McCampbell landing aboard Essex after a fight and looking back at Roy Rushing's [his wingman] a/c and seeing a piston moving in an exposed cylinder. He was surprised to see Rushing giving the plane captain a "thumbs up" indicating he thought his Hellcat was "up" for the next mission cycle. Rushing was unaware of the damaged cylinder.
     
  9. tikilal

    tikilal Ace

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    Yes this did happen, I have several stories about them this in the files, I will pull um out when I get the time.
     
  10. tikilal

    tikilal Ace

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    Well I started looking and found this. I will keep posting them as I find them.

    "Many times the Jug came home completely missing a few of its cylinders. Not making top speed, of course, but the big fan was still turning."
     
  11. mcoffee

    mcoffee Son-of-a-Gun(ner)

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    I found the source of the McCampbell account from above - it was an interview included in Bert Kinzey's "F6F Hellcat in Detail and Scale".
     

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