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Answers to Two Questions Posed by Rod

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  • dave santos
    Question One: Which is better, a thicker faster wing or a thinner bigger wing, of the same mass?   Answer: The choice is very open and complex, depending on
    Message 1 of 1 , Sep 30, 2011
      Question One: Which is better, a thicker faster wing or a thinner bigger wing, of the same mass?
       
      Answer: The choice is very open and complex, depending on many factors at once, including financing, safety, and reliability. A general prediction is that more effective systems will use the least airborne mass for the most power, in other words, uses structure close to max working loads, without ever exceeding strain limits. A special prediction is that an optimal AWECS will combine various kinds of wings, each operating in its own relative flight envelope, but interconnected by tethers. Battened membranes may be an advantaged middle-path between marginal rigid or soft wings.
       
      Question Two: How do many wings in close proximity best fly?
       
      Answer: Flocking bird formations are models for optimal group flight configurations. Larger flocking birds fly in a delta vee formation approximating a single swept wing, with washout reflex even. Each bird is staggered in formation so as to ride somewhat on the wingtip upwash of the bird ahead. A lagging bird pushing down on this upwash actually also helps a leading bird reduce its induced drag. Thus the oldest most experienced leader may not be handicapped in the "point" position in formation, but the easiest positions in a vee formation may be at the tips, in the accumulated upwash of the whole group. I have recently detected loose metachrony in group Canada Goose flapping, and disturbance waves traveling bidirectionally along their formations. Its easy to see shuffling in the group for probable optimal work rotation and pure social reasons (like mate pairings).
       
      Split wingtip primary feathers of soaring birds and fin arrangements of fish also inform multi-wing design. Some general principles are that each wing closely conforms to its apparent flow and that the overall flock (or school) operates as an optimized unit, forming a clean gentle well-organized wake. Staggered or in-line wings fly more closely spaced then stacked wings which lose lift closely spaced. Flock members avoid direct exposure to "dirty" wake of a member ahead.
       
      Crosslinked or close spaced wings tend to self-synch in common or opposed phases.
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