Contrails?

Discussion in 'Hangar Talk' started by Arnold, Jul 11, 2019.

  1. Arnold

    Arnold Pre-takeoff checklist

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    I am attaching a pic from Luscombe. It was taken 3 years ago but I just noticed there are, what appear to be contrails, coming off the prop. Contrails in that that moisture condensing through aerodynamic effect while aviating. The high speed aircraft involved is a 1946 Luscombe 8A. I just thought it was cool.

    L8A Contrail.jpg
     
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  2. cgrab

    cgrab Pattern Altitude

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    Low pressure causing moisture in the air to condense. Add carb heat just in case.
     
  3. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

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    Probably too late for that :)

    But, yea.
     
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  4. Arnold

    Arnold Pre-takeoff checklist

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    It was May in NC. Obviously humid, not sure of the temp. The condensation was not visible in flight which is why I just discovered them going through old photos this AM. That said, carb heat is a good idea and I would have used it if I had indications of carb ice.
     
  5. Arnold

    Arnold Pre-takeoff checklist

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    No indications of carb ice. Condensation off prop not visible outside aircraft. Since the engine kept running with no indications of carb ice I'm pretty sure it was unnecessary. Are you suggesting I should have used carb heat profilacticly at cruise power? BTW I posted this because I thought it was a neat photo but if you guys think it is a good jumping off point for a carb heat discussion that works too.

     
  6. bflynn

    bflynn En-Route

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    Was this an experimental delivery system? Through the prop tips? I heard about one group in the 50s that tried this and...it did not end well. Seems awfully complex for the plumbing to get from the chem tanks out into the prop.

    Joking...of course. Yes, cool picture and a reminder of what 100% humidity is.
     
  7. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

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    No problems, then no problems. Cool picture.

    (I did encounter what I believe was carb ice during cruise in a '46 Cessna 120 - dunno for sure, but the application of carb heat resumed the noise...)
     
  8. Arnold

    Arnold Pre-takeoff checklist

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    That explains it, chem trails. It is a 1946 airplane so right era and the fixed pitch prop provides fewer complexities. I bet I could gain some useful load if I remove that system. Thanks.
     
  9. GRG55

    GRG55 Final Approach

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    Very cool pic.

    But judging by the visual evidence in the picture I would say he needed to turn the injection rate down quite a bit. It's more effective as a fine, even distribution into the atmosphere, rather than the excessively lumpy, high volume shots shown here. Kids these days, they're all in a hurry to get back to their phones...
     
  10. Arnold

    Arnold Pre-takeoff checklist

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    Interesting. I think 120's had a C-85 engine. The Luscombe has an A-65 and a different carb. I don't have a mixture control.
     
  11. jsstevens

    jsstevens En-Route PoA Supporter

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    Yeah the plumbing is a bit heavy but you're swapping a hollow prop for a solid one so you lose there...
     
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  12. Arnold

    Arnold Pre-takeoff checklist

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    I wonder if I can use the venturi (lower left corner of pic) for distribution. I'm concerned it would mess up my paint.
     
  13. Pilawt

    Pilawt Final Approach PoA Supporter

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  14. Tantalum

    Tantalum En-Route

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    Contrails like this are really cool, there are some epic photos online of C130, Airbus A400, helicopters, etc. with this

    Mind you, the 1946 vintage for the early delivery system makes sense, this is contemporary with the first attempts by Bernard Vonnegut to seed clouds with silver iodide as a nucleating agent to alter the weather

    I don't think the venturi would work as well, you get a better overall mix rate injecting the stuff straight into the blade thrust at the tips where dispersion velocity is greatest

    PS... many WW2 aviators suffered from diarrhea as castor oil was used in the engine lubricants, and flying through that exhaust in big bomber formations would bring about some serious intestinal issues... there were accounts of folks landing behind enemy lines to relieve themselves
     
  15. Arnold

    Arnold Pre-takeoff checklist

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  16. Arnold

    Arnold Pre-takeoff checklist

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    Lovely thought.


     
  17. jsstevens

    jsstevens En-Route PoA Supporter

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    FTFY. Many of the rotary engines (yes, rotary, not radial) from early WW1 used castor oil and it was consumed with the fuel and blown out the exhaust. Right into the face of the pilot.

    John
     
  18. IK04

    IK04 Line Up and Wait

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  19. KRyan

    KRyan Pre-takeoff checklist

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    The venturi reminded me of a story.
    Our airport mechanic had a Globe Swift that had one. He was out somewhere and someone asked him what it was. He told them it was a horn to scare the deer off the runway so you could land.
     
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