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Is thrust linearly related to propeller-pitch?

  1. Dec 5, 2015 #1
    Simple question, Given a constant speed, is the thrust of a propeller linearly related to it's pitch?
     
  2. jcsd
  3. Dec 6, 2015 #2

    rbelli1

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    Gold Member

    No.

    Think about the thrust at 0 and 90 degrees.

    BoB
     
  4. Dec 6, 2015 #3
    What exactly is the relationship then?
     
  5. Dec 6, 2015 #4

    CWatters

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    First of all what do you mean by "constant speed"? On a plane flying at a constant speed drag and thrust are usually constant and equal to each other. If you vary the pitch and as a result you change thrust then speed will usually change.

    A prop blade is essentially a wing. Thrust from a prop is roughly equivalent to lift from a wing. Perhaps take a look at graphs of lift vs angle of attack. The shape of the curve depends on the wing section. It might be reasonably linear over a narrow range of angles...

    Just the first one I could google. I think it's a model aircraft wing section...

    fig1a.jpg
     
  6. Dec 8, 2015 #5

    rcgldr

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    If you search online for "static thrust calculator", most of them don't have an input parameter for pitch, stating that pitch (within reason) doesn't make much difference in a static situation, due to limitations of the induced flow in a static situation.

    The pitch comes into play when the prop is moving forwards. As air speed increase, a greater amount of pitch can be used on aircraft with adjustable pitch.
     
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