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Wing during a sandstorm

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  • Wing during a sandstorm

    Hi guys

    I'm designing a wing for one of my courses in uni and I need some specific info.

    How would the loads acting on an airplane wing change during a sandstorm? How would the lift and drag coefficients change? How would the mass of the wing change? Is there anything else I need to know about in terms of wing structural design?

    If you don't know, then could you point me in the right direction?

    I'm sorry if this is not the right place to post this, I'm new here.

  • #2
    Interesting question.

    Form a theoretical point of view, yes, sand hitting on the wing would cause more drag. But then also would water hitting on the wing.
    From a practical point of view, I don't think that this would be significant at all.
    Sand (or water) hitting on the wing and bouncing would also have to create some modifications of the airflow that would also affect lift.
    Again, I don't think that this will be significant at all.
    And the mass of the wing itself would not change. Why would it?

    Keep in mind that even in the worst sandstorms (or rainfalls) the actual proportion of sand (or liquid water) content is EXTREMELY small.
    A sandstorm may contain 90 thousands microgram of sand per cubic meter of air. That is about 0.000075 kg of sand per kg of air (75 parts per million by mass/mass).

    Planes fly through sandstorms (and rainfalls) not all the time but with some frequency, for sure it is many many times per year globally.
    And there are lots of issues associated with that (visibility, paint sanding, engine issues, radio issues, turbulence) but I've never heard of lift or drag issues.

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

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    • #3
      Originally posted by Gabriel View Post
      Interesting question.

      Form a theoretical point of view, yes, sand hitting on the wing would cause more drag. But then also would water hitting on the wing.
      From a practical point of view, I don't think that this would be significant at all.
      Sand (or water) hitting on the wing and bouncing would also have to create some modifications of the airflow that would also affect lift.
      Again, I don't think that this will be significant at all.
      And the mass of the wing itself would not change. Why would it?

      Keep in mind that even in the worst sandstorms (or rainfalls) the actual proportion of sand (or liquid water) content is EXTREMELY small.
      A sandstorm may contain 90 thousands microgram of sand per cubic meter of air. That is about 0.000075 kg of sand per kg of air (75 parts per million by mass/mass).

      Planes fly through sandstorms (and rainfalls) not all the time but with some frequency, for sure it is many many times per year globally.
      And there are lots of issues associated with that (visibility, paint sanding, engine issues, radio issues, turbulence) but I've never heard of lift or drag issues.
      Hi Gabe. We always appreciate shiny new members, don't we.

      1 forum post. Oh man. Gabe, did you know how you felt during your very first forum post, more than 13 years ago? Sometimes, I try to remember how I felt. December 2008. That was the time when a man from Honolulu HI started his worldwide career. And by that time, he was .. still 47 years old, he might correct me. Only in 2009, he became 48 .
      Gabe, you know what that means, don't you.

      The both of us are theoretically old enough to be it. But the better question in my eyes is, would you like to be it. I mean, a 747 in your backyard can never be wrong, who would deny that. But according to the man from Honolulu HI, a private jet in form of a 747 could also be a form of addiction. I almost quote him when he answered something like, the 747, when he was asked 'What would you miss most when you leave the Oval Office?'.

      Back on topic. A simulator would be perfect to try something like that. But I just wonder if a simulator could perfectly depict the abrasion which sand would cause in a 747 engine. Due to a very similar reason until today nobody has tried to land a 747 in the Bonneville Salt Flats. Where a 5 or 9 or 19 km long "runway" is not the problem. But somebody has perceived that the salt is quite soft. Too soft for a 747. Don't ask me how that man has found that out..
      That same man must have found out that salt and a 747 engine do not harmonize very well, because one 747 engine basically works like a giant vacuum cleaner. Which would suck salt or sand, in case of a doubt. And you have 4 such giant vacuum cleaners in a 744 cockpit. Again, do not ask me how he ..

      I know that the 747-400 freighter until the year 2017 was also used in the desert,
      with temperatures of +48C - i.e. 118,4F - or more. I mean the EK-B744ERF freighter, UAE. Not necessarily the material is a problem in my eyes, I know cases where engines (on the ground) have sucked material or even smaller devices like luggage trailers etc.

      With my new friend Evan I have just discussed how big such a B744 engine is. In case of my avatar we talk about the GE CF6-80C2 engine, Evan might correct me.
      One GE CF6 engine in a 747-400 has a diameter of 93 inches, i.e. 2.36 meter. And such a 747-400 has four GE CF6 engines.

      We don't have to imagine everything that fits into such a giant vacuum cleaner. Sand, salt, animals, luggage trailers, ... So the material is not necessarily the problem,
      but rather the temperature.

      I don't know if I have ever used Randazzo's LH-B744 simulator during a take off procedure with +48C i.e. almost 119F. Probably not.

      There is one airport on this beautiful planet where the people always have played (!) in the sandstorm which was caused during a 747 t/o procedure.. Here it is.
      Probably my favorite jetphoto of all times, and still online, more than 30 years old (April 1991):

      https://www.jetphotos.com/photo/162743

      Now we could ask the photographer who made this brilliant jetphoto. How do the wings of a 747 behave on a beach, on a sandy runway. I'd say, quite perfect, because AF did not only operate their B741 on that beach but later also the AF-B744.

      PS: Nowadays, that beach is afaik no longer visited by a 747, because Air France does no longer own one 747. Today on that beach you might see Airbus A330, not quite a 747, but big enough for a sandstorm.
      I do not know all the a/c types of today for Princess Juliana. An update would be appreciated. Who knows more?
      The German long haul is alive, since more than 60 years.
      The Gold Member in the 747 club, 50 years since the first LH 747.
      And constantly advanced, 744 and 748 /w upper and lower EICAS.
      Aviation enthusiast, since more than 35 years with home airport EDDL.

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