1. Elven Candy

    Elven Candy Pay no attention to the foot in my mouth Contributor

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    How high would a dragon have to fly to not be seen by humans?

    Discussion in 'Research' started by Elven Candy, Jan 9, 2017.

    I'm working on writing a book about a dragon and this one question keeps popping in my head: How high must he fly to be out of sight of humans? The answer isn't super important to my story, as I don't get that specific in it and I just assume he can do that, but the question still bugs me. I couldn't find anything in google, so I thought I'd ask here and hope someone has at least a rough suggestion.

    He's about twenty feet tall with a wingspan I haven't specified (I'm not scientific enough to figure that kind of thing out). His body frame is about like a typical dog, not too long or short and not too thick or thin.

    If anyone can give me a rough estimate, I'd really appreciate it.
     
  2. Shadowfax

    Shadowfax Contributor Contributor

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    It's not too difficult to see an airliner at 30,000 feet - on a clear day!

    A Boeing 777 has a wingspan of 61m = c. 180feet.

    Your guy is about 1/10 that size at 20 feet tall, so I'd expect to be able to see him, albeit as a bit of a dot in the sky, at 3,000 feet. Give or take a bit.
     
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  3. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    Yeah, but you have to have very sharp vision and be specifically looking for it to see it, and even then, you only know what it is because you've seen one before. I doubt you'd be able to detect a 777 in the sky if it weren't for those engine trails. Hell, ISS is visible with the naked eye if you know exactly where to look.

    ElvenCandy, do an experiment. Draw out a small dragon and go further and further away from it until you can safely say that you wouldn't notice it at a quick glance (remember that the sky has glare too.)

    If you know how far away from your little drawing you have to be and the width of your drawing, you can scale up to your value.

    If you want theoretical: W / tan(0.02 deg) where width is the size of the dragon. (0.02 degrees is the minimum resolution of our eyes.) That's assuming perfectly clear skies, 20/20 vision, and someone actually looking for it.

    Small, flying objects, are quite difficult to spot. The luftwaffe's planes were heard before they were seen and were probably bigger than a dragon. Finding them was why we invented radar.
     
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  4. Cave Troll

    Cave Troll It's Coffee O'clock everywhere. Contributor

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    Well just have them be able to fly at about 5000 feet, and then there really is no
    way you would see a 20-40 foot long dragon flying around. :p
    Besides you wouldn't even hear them coming at that altitude, because wings don't
    produce enough noise to be heard unlike a plane does with engines.
    Now don't go making dragon that can bomb castles. :p
     
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  5. Shadowfax

    Shadowfax Contributor Contributor

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    Heinkel 111 wingspan 21m = c. 66 feet = 3 times your dragon...but they flew at 16,000 feet...
     
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  6. Iain Sparrow

    Iain Sparrow Banned Contributor

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    Treat the dragon like a bird. Its wings would have to be shaped like that of high soaring birds... and also, like some birds the underside of the wings and body might be lighter in color than the top half of the body, which would help disguise it during daylight hours from possible onlookers below.
    Large birds, such as eagles, have a ceiling of about 16,000ft... a dragon's ceiling would be much the same as that of the Pterosaur... listen to the NPR link below, quite amazing that this dinosaur was very similar to some mythical dragons.

     
    Last edited: Jan 9, 2017
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  7. Elven Candy

    Elven Candy Pay no attention to the foot in my mouth Contributor

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    Thank you so much guys! I was a little worried the idea was totally unrealistic.
     
  8. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    asin(40/5000) = 0.5 degrees. That's about the size of the moon from our perspective.

    Don't forget that the higher you go, the faster you have to go due to air pressure. Evolution would produce a near-perfect air-foil, but even a perfect one has limitations in low atmospheric density, especially when considering the mass of your dragon.
     
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  9. Cave Troll

    Cave Troll It's Coffee O'clock everywhere. Contributor

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    Yes well it is Fantasy where mythological creatures can do what you want.
    If this was Sci-fi then there would need to be an explanation as to a dragon flying
    in low pressure/high altitude. Maybe these dragons have an air intake/exhaust
    system that would allow them to fly at higher altitudes.:p
     
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  10. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    Probably, I always assume dragons have some sort of magical ability that allows them to fly. Most writers ignore the area squared vs volume cubed law.

    Still would have to be higher than 5000 ft though, a 40 foot dragon would be easily visible assuming it's not camouflaged and you're specifically looking for it. If it's the apex predator and always has been, there would be no evolutionary pressure to cause it to hide.

    It should be noted though, that to primitive man, there's really not much reason to look up. Our species is too large to be picked up by a bird of prey nor could we really hunt flying animals, so we evolved to basically ignore the sky.
     
  11. Elven Candy

    Elven Candy Pay no attention to the foot in my mouth Contributor

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    I have to admit I don't understand the 0.5 degree stuff (math was my worst subject), but I do plan on making him be able to fly at least as high as a bird, so he can definitely fly higher than 5,000 feet.

    The humans in my story are preyed upon by griffins, too, so unfortunately they do have a reason to look for predators in the sky.
     
  12. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    I'll explain a little. You don't really need the math, I could do that for you, you just need to know the concept.

    So you know you can't see all the way around you right? If you could, you'd have 360 degree vision (360 degrees in a circle.)

    [​IMG]

    We can actually see about 120 degrees in total. So everything you see, fits in that field, so that's how we measure how much of our view something takes up.

    So thing of the following image
    [​IMG]
    Here you see something 108 inches away that has a viewing angle of 10 degrees. You know that you your total viewfield is 120 degrees, it takes up about 1/12th your view (put your hand up at arms length, that seems like about 1/12th of my vision.)

    Now you know if you brought your hand closer to your face, it would take up almost your entire vision, and if you moved it much further away, it appears smaller because it's a smaller and smaller part of your overall 120 degree vision.

    When dealing with the sky, it's nice to just know that the moon is about a half a degree of your field of view. You can cover the moon with your thumb at arms length, so it's small, but certainly not unnoticeable.

    How you determine angles from lengths and vise versa is with the thing you probably learned about in school SOH CAH TOA
    [​IMG]


    For comparison, Jupiter appears about 1/100th of a degree in the sky, but without binoculars, you can't identify it as anything other than a point.
     
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  13. big soft moose

    big soft moose An Admoostrator Staff Supporter Contributor Community Volunteer

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    Maybe it only hunts when its cloudy - in that case he only has to fly high enough to get into the cloud deck.

    Or may be there's often morning or evening fogs cause by river valleys, wetlands whatever and he hunts under the cover of these (so he could be practically at ground level)

    Or hell he's a dragon, may be he can make himself invisible while flying , or may be he's like a shape shifter and takes the form of something humans don't usually fear like an eagle when hunting.
     
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  14. Cave Troll

    Cave Troll It's Coffee O'clock everywhere. Contributor

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    Damn it! Now we have to fear the stealth dragon?

    Actually the cloud cover thing actually works.:p
     
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  15. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    I'm also wondering how important it is for stealth. A fox can see an eagle coming from a pretty good distance. If it runs, the eagle is perfectly capable of tracking it, and is flying much much faster than the fox can run. Birds of prey rarely rely on stealth, it's about the ambush and speed.

    Like I said, very few thinks look up. Most birds of prey attack by dive bombing. Being able to see a raptor coming down on you at 100mph doesn't really help you much when you can run at a measly 20.
     
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  16. Elven Candy

    Elven Candy Pay no attention to the foot in my mouth Contributor

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    Thanks newjerseyrunner! That makes a lot more sense now.

    I debated on giving him some kind of color-changing/camouflaging ability, but decided not to. He really doesn't hide from humans all that often--he's not afraid of them as they're usually not a threat. But when he does need to be out of sight and flying, I need to know how he can hide, y'know?

    Funny how I always forget about clouds . . .

    :superlaugh:

    Dive-bombing is his favorite method of hunting. Most dragons in my story don't actively hunt humans, or don't hunt them for long, as they know humans will band together and kill them. They also prefer fewer bones and more meat than we provide. Really, it's only when he's passing over human territories and doesn't want to cause a ruckus that he has a need to hide from them. I've just reached a part of the story where he's doing this a lot, so it's started to really bug me.
     
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  17. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    I don't think he'd make much ruckus unless he got really close. A far away dragon would be indistinguishable from a nearby smaller bird.
     
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  18. Dnaiel

    Dnaiel Senior Member

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    Curious, if this is a fantasy setting, are you going to use foot as a measurement? And would people even be able to estimate such huge distances?
     
  19. JLT

    JLT Contributor Contributor

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    I'd say about a thousand feet, unless you already know where to look.

    Why do I say that? Well, I spent twenty years hang gliding, much of which was spent in the landing area, looking for fellow pilots who were still aloft. Our gliders typically had about a thirty-foot wingspan. If the launch was a thousand feet over us, we could usually (but not always) see them take off. If there's any thermal activity in the air, the gliders are harder to see due to the turbulence of the air. If they gained a lot of altitude, we'd lose them against the glare of the sky, and only see them again once they'd descended to about a thousand feet over us. They became considerably easier to spot once they were about six or seven hundred feet over us, and by the time they got down to five hundred feet, we could usually tell whose glider it was from the colors of the wing.

    Like dragons, hang gliders flew silently, so you couldn't use your ears to locate them like you can with airplanes.

    (Interesting side note: the German slang term for a hang glider is a "dragon." And in homage to that, my publishing company is called Dragonwing.)
     
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  20. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    Great answer JLT, one question though: 500 feet from the glider including horizontal distance, or when the glider is 500 in the air?

    If the dragon became fairly obvious at 500 feet up, you have about 30 seconds before it'd be on you. It would take 77 seconds to simply drop from 500 feet and Id assume by 500, it'd already be in its dive bomb.
     
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  21. Elven Candy

    Elven Candy Pay no attention to the foot in my mouth Contributor

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    So far I've managed to avoid measuring by distances except to say "dragon-lengths" one time. He's a dragon, and doesn't measure like that so I'm trying to avoid it unless necessary for the reader.
     
  22. Dnaiel

    Dnaiel Senior Member

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    Did you figure that as the terminal velocity? Because I would bet a dragon could exceed that with enough strength and experience.
     
  23. Cave Troll

    Cave Troll It's Coffee O'clock everywhere. Contributor

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    What about in Cubits?
     
  24. newjerseyrunner

    newjerseyrunner Contributor Contributor

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    No, I simply assumed a dragon falling in a vacuum. I cancelled out the air resistance with powered flight. I cut the time in half to compensate for the fact that it'd likely already be diving and not starting at a velocity of zero.
     
  25. Homer Potvin

    Homer Potvin Get off my Balzac... Staff Contributor

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    This dragon is going to do some serious damage if it ever gets off the ground...
     

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