Radial too hot

Discussion in 'Engines' started by Daddio, Oct 15, 2007.

  1. Daddio

    Daddio New Member

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    How can I cool this ol' girl down?
    I operate a Pratt Whitney R-2800 CB-3 as a wind generator at our test lab. She runs very well, but gets a little warm in the Fresno summer sun. The test runs are usually between 15 and 25 minutes long, including a warm-up to operating temperature before the test. I'm using 100LL in the tank and Aeroshell W120 in the reservoir.
    Running stationary, obviously I don't have the kind of airflow across the cylinders or the oil cooler she was designed for. I am told removal of the cowling results in warmer running temperatures. The cowl flaps were remvoed long ago. Would replacing them and running with the flaps open result in better air cooling of the cylinders? I thought with those flaps sticking out into the wind it might draw air through the cowling better.
    Any other stationary cool-running tips?
    Thank you!
     
  2. Micdrow

    Micdrow “Archive”
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    Interesting use of a Pratt Whitney. Im not sure there is a cure. Maybe some one else will have more info.
     
  3. comiso90

    comiso90 Active Member

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    If I may ask, what test lab is that?... I'm Fresno too..

    .
     
  4. mad_max

    mad_max Member

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    Does the prop have blade-cuffs? Thinking maybe the prop was rebuilt and the blade-cuffs
    weren't replaced. Radials like these cuffs as they push air into the cowling better.

    Don't really know if replacing the cowl flaps and having them full open would make much
    if any difference. Maybe google up an engine rebuilder that specializes in radials and
    ask them how they keep them cool while testing and breaking them in before shipping.

    FWIW
     
  5. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    You need to get baffling around the engine. Put the cowling back on and try to install the original baffling. Keeping the cowl flaps open won't help unless the cowl and baffling is properly installed. Also run as rich as possible. You'll burn more gas but it will also keep your engine cooler.
     
  6. mad_max

    mad_max Member

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    Here's a link with names and websites of rebuilders. I'm sure one of them may be
    of help if you'd email them a nice letter.

    de_links_33
     
  7. Daddio

    Daddio New Member

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    (huh? I thought I posted a reply already. Theme to Twilight Zone...)
    Great tips - thanks all around!
    mad max: Do you know where I can get blade cuffs? I pictured that a year ago, but didn't know they existed.
    flyboyj: To clarify - this engine does have the cowling installed, but I don't know if all the "baffling" is installed. (I heard this came from the #2 spot on a "C-6", but I think it must have been a "DC-6". This was years ago.) What baffling are you talking about?
     
  8. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    There should be some shrouds or plates between the cylinders, especially at the first bank of cylinder heads. Sometimes the spark plug wires will be going through them. I found this on line and circled some examples.
     

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  9. mad_max

    mad_max Member

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  10. GADGET

    GADGET Member

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    Try to enrich mixture a little bit.
     
  11. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    And not to burst Mad Max's bubble, but those blade cuffs are STC'd. They are going to be pretty expensive and personally i don't think they are going to help much. Make your own if you want to try that...
     
  12. mad_max

    mad_max Member

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    Not bursting my bubble. I'm no AP..just trying to give suggestions. :lol: No pain
    here flyboy.

    Running it rich is a good idea. Maybe even run it with water injection from an unlimited
    supply of water like the stationary test when they pulled 3000+ HP from it.
     
  13. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    All good Mad Max! Now the water injection sounds like an idea....
     
  14. Daddio

    Daddio New Member

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    It dawned on me that actual numbers really should be used here. Whoever set up this instrument panel marked an acceptable CHT range with green lines, but based on what - not sure. Furthermore, it was set up for running in the northeastern US.
    What really is "too hot" for her?

    I'm also wondering how to find out what sort of bird she used to pull.
    There are now some shot in my album.
    (Does that link work? e-greenhorn here)
     
  15. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    An R-2800 CB3 is a civilian engine. That looks like a DC-6 QEC without cowl flaps. Check this out...

    [​IMG]
     
  16. wilbur1

    wilbur1 Active Member

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    Could you possibly run it on alcohol or methanol? thats what we do with our air cooled drag cars.
     
  17. Daddio

    Daddio New Member

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    This summer is as hot as ever in Fresno, but after a good bath (long overdue), the ol' girl runs much cooler. I used kerosene in a pneumatic sprayer for hours going over the engine. Some cylinders have such heavy buildup, I may have to get more aggressive. Some cylinders have a thin but persistent varnish coating. About half of them came completely clean though, and - imagine that - cooling improved dramatically. After giving the same healthy treatment to the oil cooler, I'm expecting great things in the Fresno heat.
     
  18. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    Amazing what a little engine cleaning could do!
     
  19. r2800doublewasp

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    Great engine choice! :)
     
  20. Daddio

    Daddio New Member

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    Nice picture! :)
     
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