Discussion in 'Biology & Genetics' started by Tristan, Sep 19, 2004.

  1. CANGAS Registered Senior Member

    Hang gliders represent the minimal wing capable of supporting a human. But, if you want to control your flight instead of just drop in a steady glide? Then you need to increase your overall body muscle strength by a considerable factor, so you can flap those big wings.

    No pain, no gain. It is extremely doubtful that any human could or would tolerate the painful discomfort needed to exert the amount of muscular effort to not only glide but to climb and cruise.

    A pterodactyl is a rough analogue to a human size and weight, and it apparently flew. How much muscular pain are you willing to endure? On a scale of 1 to 10, about 500?

    I am aware that human powered sustained flight has been a historical fact for decades. My response is in terms of the apparent thread point of small and convenient wings.
    Last edited: May 13, 2006
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  3. Dinosaur Rational Skeptic Valued Senior Member

    I hope that some day people will stop referring to the physics of bumble bee flight.
    Some dummy with a knowledge of aerodynamics as applied to fixed wing aircraft made a stupid statement (I wonder about the context). The statement might have been made at a time when nobody understood the dynamics of bumble bee flight. However, I am sure that even the person who made the statement was neither denying that bees could fly nor was he claiming that it was due to some supernatural phenomena.
    While I am well aware of the muscle power required to flap wings capable of allowing a human to fly, I think that flappable wings could be smaller than current hang glider wings. I am sure that there is a factor of safety in hang glider design. Even glider wings could be smaller than hang glider wings, and flappable wings even smaller that that.

    I agree with the view that a flying human would have to look more like a bird than a human.

    Some questions about Pteradactyls.
    • Could they take off from a flat plane in still air?

    • Were they gliders or did they really have powered flight? Remember that a glider taking advantage of thermal updrafts and other aerodynamic principles can gain altitude.

    • Was a Pteradactyl body comparable in weight to a human being? Even if it was approximately the same size, it could be a lot lighter due to hollow bones, extra lung capacity, lower density of various tissues.
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  5. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    I doubt that it is simple statistics for following reason:

    If each bird makes a 50/50 choice to be on right or left side of V then large V (lots of birds) would have more equally balanced V than small Vs (few birds total) by the law of large numbers (Same reason the ratio of head to tails always approaches unity as the number of coin flips increases.)

    I no longer live where I can see many Vs, but when visiting my father years ago on the Eastern Shore of Maryland, I saw many Vs, often if not usually, quite "lop-sided". Perhaps 20 birds on one side and only 7 on the other. (Try making 27 coin flips and see if a head tail difference of 13 (or more) is a common occurance. - I think not.)

    I would suggest that the Direction of Flight, DF, is rarely directly aligned with the Wind, W, and, for example, that even when the angle DF/W is only 15 degrees, then it may take significantly less energy to fly on one side of the V than the other (Energy required is not symetric as there are are TWO aerodynamic effects being added. - The Trailing Lift, TL, from mainly the bird directly in front and the wind, W. The TL is of course always alinged with the DF, and rarely with W. That is, on one side of the V you have the vector sum W+TL and the other side W-TL which would rarely be equal.)

    Birds are Bird-Brained, but I suspect they understand this better than some here. If some one lives where they can see many Vs, perhaps they will test my theory by seeing if the long side of the V is correlated with the wind direction. Clearly the case with W and DF aligned will be "purely stastical" so another correlation to check is if the bird count difference in the sides of the V increases with the angle between DF and W. Also does it violate the law of large numbers for large Vs?* Perhaps the observations should be weighted. I.e. more weight given to the cases with (1) larger differences in the bird count in sides of the V and (2) with the larger differences between DF & W.
    *That may be the easiest (and best test) as one need only count the number of birds on each side and need not know the wind direction (which may not be same as at ground level.)
    Last edited by a moderator: May 14, 2006
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  7. Naat Scientia potestas est. Registered Senior Member

    From that I suggest that it is easier to fly on one side of the "V", probably because of wind.
  8. Hapsburg Hellenistic polytheist Valued Senior Member

    Considering a basic height of 2m, a wingspan of maybe 6-8 meters would be about accurate.

    Maybe, depending if you want them to be wings like a bird/bat or wings like an insect. Both structures are differently built.
    But...why the hell would you want to do this in the first place? :bugeye:

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    Last edited: Jul 2, 2006
  9. spuriousmonkey Banned Banned


    California Condors can reach wingspans of 2.8 m (over 9 ft) and can weigh up to 8.5 kg

    An 8.5 kilo bird needs a wingspan of almost 3 meters. Do you think 1 meter more will lift a 70kg human?

    Argentavis magnificens, sometimes called the Giant Teratorn, is an extinct bird from the late Miocene (5 - 23 million years before present) of South America. It is the largest flying bird ever discovered.

    Physical characteristics
    Wingspan: 7 to 8 m
    Wing load: 1E2 Pa (estimated)
    Length: 3.5 m
    Height: 2 m
    Weight: 80-100 kg (estimated)

    So we would need something like 7-8 meter wings

    Sources Wikipedia
    Last edited: May 15, 2006
  10. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    I agree. see my post just prior to yours, but do not follow why you would conclude from your reference that one side of V would be better than the other. To do this, you need to make the argument I have already given.
  11. Naat Scientia potestas est. Registered Senior Member

    I donĀ“t know how I missed your explanation.

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    Well, then lets just say that I support you theory.
  12. valich Registered Senior Member

    No matter the wing size, but as was stated above, we'll never evolve the muscles needed to articulate the flapping of wings. Why should we? There's no environmental nitche to support mutations needed for flight adaptation in humans. Any change in our environment that would necessitate this would occur with such a sudden time-frame that it would not allow for the gradual evolution of flight, or the evolution of wings, to occur.
  13. Ophiolite Valued Senior Member

    It had long been understood that aerodynamically there were advantages to slipstream the lead goose, whilst avoiding the turbulence in its immediate wake. However, this understanding had always been based upon equal applications of common sense and FEA aerodynamic models. Recently, in 2001, a French team demonstrated a genuine advantage to formation flying.

    Weimerskirch et alNature 413, 697-698 (18 October 2001)
    Many species of large bird fly together in formation, perhaps because flight power demands and energy expenditure can be reduced when the birds fly at an optimal spacing, or because orientation is improved by communication within groups4. We have measured heart rates as an estimate of energy expenditure in imprinted great white pelicans (Pelecanus onocrotalus) trained to fly in 'V' formation, and show that these birds save a significant amount of energy by flying in formation. This advantage is probably a principal reason for the evolution of flight formation in large birds that migrate in groups.


    One observes that the lead bird in any formation is constantly changing, so that the head of the V-moves left or right, down or up, the V over time. This is responsible for the assymetric character of the V.

    On the topic of humans with wings, it would be quite straightforward on a low gravity planet. The size would be completely manageable. [The problems would emerge when the winged human returned to his home planet. One can imagine a 23rd century bio-engineered Martian inadvertently stepping off the Empire State Building, flapping his wings ineffectually and wearing a startled expression.]
  14. CANGAS Registered Senior Member

    Any poster who has ever exerted their muscles to their apparent limit, if there are any such in this thread, has the painful memory of how using muscles beyond a very lazy limit is not fun.

    Chimpanzees, to use only one example, have the strength of several humans, pound for pound. It is not because of a profound difference in muscle composition, but, because humans have a neurological pain cut off point far below that of chimps. Chimps continue stressing their muscles beyond the level of pain that humans cannot tolerate.

    A human might have the essential muscle strength to sustain flight by flapping a set of artificial wings, on Earth, but it would require a pain tolerance that would be unusual, to make an understatement.
  15. Fraggle Rocker Staff Member

    Don't forget that you have to have a breastbone to anchor those wings to. Many years ago in a sci-fi story the author made a very careful and realistic calculation of the wings a horse would need in order to actually fly and fulfill some rich person's fantasy of having a real Pegasus. It turned out that the horse would need something like a fifty-foot wingspan in Earth gravity. But far worse for the project: He would need a breastbone that extends down about twice as far as his legs.
  16. Dinosaur Rational Skeptic Valued Senior Member

    I find the following hard to believe.
    I would like to see a source for this. While the average human being might be limited by a pain threshold, serious athletes are not so limited.

    The following is flat out absurd.
    A human running a bicycle-like device is likely to be able to apply the most muscle power to any given task. We could not come close to designing a flying device powered by human muscles flapping wings. A hang glider is the best we can hope for without redesign of the human body.

    I doubt that we could develop enough muscle power via a bicycle-like mechanism to run either a fixed wing airfoil using a propeller or a helicopter-like device. Either of these devices would probably be more efficient than attempting to flap wings.
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Glad to see this alternative to my explaination for the asymmetry as experimental data should be able to tell which is correct. In my theory the longer side will be correlated with the direction of the cross wind and in yours it will not be. Both your theory and Valich's basically claim that it is stastically random choices that develop one arm of the V longer than the other and very large difference in the length of the two arms of the V should be rare just by the law of large numbers. (same reason long runs of all heads are rare in coin flips.) My theory predict that in realtively stong cross winds, one side will often be significantly longer than the other and always correlated with the side the wind is coming from. Now all we need is the data.

    You quoted me as stating: "I wonder why birds fly in a V?" I am very surprized that I stated that as I have long thouhgt I knew the answer. - it takes less effort and I even spoke of the lift the wake of the bird ahead gives to the trailing bird. I looked back at my recent posts and did not find that statement by me. If I made it where is it? I want to see the context.
  18. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    I agree competely with you, but I want to add that the statement is very likely without foundation because pain is a very subjective thing. - Almost impossible to compare between two humans, surely impossible to compare the pain of a human with that of a chimp. For example, if a lighted cigarette is pressed hard against my heel for 1 second is my pain twice, half or same as yours would be in the same circumstance - not possible to know. The statement that chimp feels only fraction of the pain a human does in a strenusous work out is much more difficult to argue.
  19. CANGAS Registered Senior Member

    How many of the posters who write so knowingly of the importance of the pain threshold as a limit to the practical strength that a human can exert have actually used their own body musculature to a point where they cannot go beyond the pain?

    I have.

    It is a well established fact that, pound for pound, many, many animals have exhibited far greater useful strength than humans.

    Regardless of whether it is because of a pain threshold or another factor, the fact is that even an unusually strong human is very unlikely to be able to exert enough sustained effort to be able to flap artificial wings and fly at will. On Earth.

    Sorry, Charlie.
  20. valich Registered Senior Member

    Pain or not, we do not have the muscular ability to flap wings of proportionate size to get us aloft. But you are right that normally we would not exert enough sustained effort in what we do have. But if you work out with weights, you know that you have to pump iron till it hurts. No pain; no gain. Any coach will tell you that you have to workout till it hurts to get the max benefit.
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    As I have frequently placed 20 pound rehesus monkeys in restraining chairs, I can confirm this. It is difficult and dangerous as they do not like it and are very strong. (In adition to the possibility that they may bite you, they may carry the Simian B virus, which for them is just a cold, but often fatal to humans, so even if they only scratch you, it can be fatal.)
  22. draqon Banned Banned

    Personally I believe that the only way humans can fly is to have both huge wings, strong muscles, and most importantly very strong legs...that will allow humans to take advantage of the lift by running.
  23. Mit Registered Member

    to be able to fly wherever and whenever you want would be great. many people say this might happen in the future but how for (more specific) long till that time comes for us humans to get our wings

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