Pitot tube assembly

Discussion in 'General Experimental Aviation Questions' started by 4trade, Dec 6, 2012.

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  1. Dec 6, 2012 #1

    4trade

    4trade

    4trade

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    I am building Cassutt, and i want to build pitot tube under the wing. Mostly these are in a wing leading edge, but that assembly will be too vulnerable because most bystanders don´t notice it before too late.

    I want to build it close to the LE, just underneath it, and my question is: How much i need to keep clearance for wing surface to keep it out of disturbance of compressing air at LE?

    I really don´t want to hang it too low, these ones like Cessna look like dirty launder hangers...
     
  2. Dec 6, 2012 #2

    bmcj

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    Put a sharp point on it and most bystanders will only make that mistake once! :gig:

    I don't have a ready answer for you, but what about a very large, brightly colored warning cover that you can slip on the tube while on the ground?
     
  3. Dec 6, 2012 #3

    4trade

    4trade

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    I want to avoid that warning cover...
     
  4. Dec 6, 2012 #4

    Battson

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    You could use a L-pitot and not install the longer boom? Just cut it to the desired length.

    As you say, the air pressure increases around the L.E. with a pressure gradient as you move away, so you will need someone with computational software to determine what the error will be as you vary the distance. It will be a gradient of error with distance, not a good or bad turning point.
     
  5. Dec 6, 2012 #5

    Himat

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    Have you considered to place the pitot tube protruding from top of the vertical fin?
    At least it's away from bystaners there.
     
  6. Dec 6, 2012 #6

    4trade

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    I want it out of propwash, it might get some dirt/ dust inside over there. I will use that plane sometimes in unpaved airfields here. I don´t like how it looks too, it disturb aircraft fine lines.
     
  7. Dec 6, 2012 #7

    SVSUSteve

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    That is one thing I am considering for the Praetorian.

    ...or a ring of orange "snow fence" and a few Claymores?
     
  8. Dec 6, 2012 #8

    SVSUSteve

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    Wait....how is the top of the vertical stabilizer likely to accumulate dirt and dust more than one slung under the wing?
     
  9. Dec 7, 2012 #9

    4trade

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    Tip of wing pitot it is out of propwash, but this plane is low taildragger, and tip of stabilizer is low in this plane....probably there is no, or very little dust but it may happen. Airfield close by have sand road type of taxiway on a hangar area. It is easier to mount on a wing too.
     
  10. Dec 7, 2012 #10

    Battson

    Battson

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    You could put an L boom on top of the wing. Offering no advantages over the underside of the wing, other than being more visible... hah!

    I assume it's a low wing, if people are walking into the leading edge? So you wouldn't really see an L boom under the wing would you?

    You don't have a lot of other options really, given those criteria...

    If it were a pusher you could put it in the nose cone.

    Otherwise I am out of ideas.
     
  11. Dec 7, 2012 #11

    Detego

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    Pitot tube mounted under the wing of a Cessna 172

    pitot tube_Cessna 172.jpg


    Here the large pitot tube is replaced by the small
    opening on the nose of the left wheel pant.

    symmetry-pitot-0704-1a.jpg
     
  12. Dec 7, 2012 #12

    pwood66889

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    Couple thoughts, Trade.
    * Look up one of your local Ercoupes. They are low wingers with P/S mounted under the wing. Placement is critical; leading edge problems, etc.
    * Use the designed Pitot - just unscrew it upon landing. Place it in the seat so you'll notice as part of the prefilight...
    Percy in SE Bama
     
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