Wings, Flight and Feathers
INTRODUCTION: HOW DO THEY DO IT?
John R. Hutchinson (edited by Kevin Padian and Dave Smith)
Flight is an amazing accomplishment, evolved only three times in the 500 million years of vertebrate history. By contrast, the invertebrates have only evolved flight once: in the insects, which were the first animals to evolve flight. We won't discuss insect flight here, as the diversity of flight types seen in insects really deserves a set of exhibits all its own. Good sources about insect flight include "The Biomechanics of Insect Flight", by Robert Dudley, and "Solving the Mystery of Insect Flight" by Michael Dickinson (Scientific American, June 2001). However, the same rules that govern vertebrate flight also apply to insect flight, so you can also use the information given here when considering insects. The question is, how do vertebrates manage to overcome the weight of their bodies in order to take to the skies?
Let's look at how different animals move through the air, and then see what flight is all about.
https://ucmp.berkeley.edu/vertebrates/f ... intro.html
THE PHYSICS OF FLIGHT
John R. Hutchinson (edited by Dave Smith)
To understand flight, you must have a basic knowledge of the principles of physics, in this case categorized as biomechanics. Individuals at the UCMP and the Berkeley Department of Integrative Biology are leading experts in this field, which applies the laws of physics to organisms in an effort to understand how organisms function, and to perhaps answer questions such as : "How do organisms work?," "How do the laws of physics limit what organisms can do?," or "What can physics tell us about evolutionary possibilities for organisms?" and so on. If you particularly enjoy these exhibits, try our dinosaur speeds exhibit for a similar exercise in biomechanics.
https://ucmp.berkeley.edu/vertebrates/f ... ysics.html
GLIDING AND PARACHUTING
John R. Hutchinson (edited by Dave Smith)
As discussed previously, the difference between powered flight and gliding is the flight stroke, which produces thrust in true flyers. Gliders, then, do not produce thrust; they do not flap their wings. Indeed, a glider might compromise its lift production (i.e., fall) if it tried to do so — its gliding membrane would be too small to maintain enough lift to keep the animal aloft.
When looking at the structure of an animal, without knowing its behavior (whether it flies or not) we can note some common differences between typical flyers and gliders. Most importantly, flyers have an elongated distal wing, which is flapped to produce thrust. To flap the wings, they need strong shoulder muscles, so a keeled sternum (breastbone), large humerus (upper arm bone), and modified shoulder girdle are indicative of powered flight. Also, the forearms of flyers are more elongated than in gliders, although the hands exterior to the wing are usually small. Flyers need a rigid, confined power stroke to enhance stability, so motion of the arms should be limited by the joints that are involved in the flight stroke. And the wing should be stiffened by some structural elements (e.g., fibers in pterosaurs, feathers in birds, fingers in bats).
In contrast, gliders usually retain the locomotory abilities of their ancestors, most notably climbing and leaping adaptations (which include mobile joints and large hands). Some gliders have elongated ribs which support the gliding membrane (no flyers do this). Aerodynamically, gliders are less manoeuvrable (although they can still be very manoeuvrable) and have a lower aspect ratio (wing length/wing breadth) than flyers. So, if we find the remains of an animal, we can be pretty sure whether it glided or flew.
https://ucmp.berkeley.edu/vertebrates/f ... iding.html
John R. Hutchinson (edited by Dave Smith)
The most diverse group of flyers ever to evolve are the birds (the clade Aves). Birds show a marvelous diversity not only of species but of flight adaptations. Compare the hummingbird with the albatross, and you'll get a good picture of how differently animals can fly. As is discussed in our bird origins exhibit, current theory holds that birds had a common ancestor with dromaeosaurid dinosaurs during the Late Jurassic period (about 150 million years ago), if not earlier. Birds remained of relatively low diversity until the Cretaceous period.
Thermal soaring flight of birds and UAVs
Zsuzsa Ákos, Máté Nagy, Severin Leven and Tamás Vicsek
Abstract. Thermal soaring saves much energy, but flying large distances in this form represents a great challenge for birds, people and Unmanned Aerial Vehicles (UAVs). The solution is to make use of so-called thermals, which are localized, warmer regions in the atmosphere moving upwards with a speed exceeding the descent rate of birds and planes. Saving energy by exploiting the environment more efficiently is an important possibility for autonomous UAVs as well. Successful control strategies have been developed recently for UAVs in simulations and in real applications. This paper first presents an overview of our knowledge of the soaring flight and strategy of birds, followed by a discussion of control strategies that have been developed for soaring UAVs both in simulations and applications on real platforms. To improve the accuracy of simulation of thermal exploitation strategies we propose a method to take into account the effect of turbulence. Finally, we propose a new GPS independent control strategy for exploiting thermal updraft.
Lift is a meteorological phenomenon used as an energy source by soaring aircraft and soaring birds. The most common human application of lift is in sport and recreation. The three air sports that use soaring flight are: gliding, hang gliding and paragliding.
Energy can be gained by using rising air from four sources:
• Thermals (where air rises due to heat),
• Ridge lift, where air is forced upwards by a slope,
• Wave lift, where a mountain produces a standing wave,
• Convergence, where two air masses meet
Posted by Solo: viewtopic.php?p=616308#p616308
The reasons why bird wings are so amazing
By Christina Holvey
Why does an albatross soar on slender, motionless wings while a little house sparrow flaps small, stubby ones nineteen to the dozen? The shape and size of a bird’s wings are defined in no small part by their owner’s travel requirements, as well as by their lifestyle. Here’s your guide to the wonderfully revealing world of bird wings. ...
Thermals are created when the sun warms the ground, which in turn warms the air directly above it. The warmer air close to the surface expands to become less dense than the surrounding air and rises, taking even large and heavy birds such as eagles, hawks and storks along for the ride. Using these invisible elevators, golden eagles can climb several hundred metres without expending any energy. Once high in the skies, they are able to soar effortlessly around at an unhurried speed of 30mph, which is perfect for surveying their territories and spotting prey.
Storks use passive soaring wings for a different reason – to navigate long migration routes. White storks (Ciconia ciconia) journey annually between Europe and Sub-Saharan Africa and, for many, the shortest route would take them over a large stretch of the Mediterranean Sea. As air thermals don’t form over water, however, the storks would have to employ energetic wing-flapping to use such a route, a technique that burns 23 times more body fat than soaring over land. Instead, they cross over at the Strait of Gibraltar, where Europe and Africa are separated by a mere 7.7 nautical miles of ocean.
The storks rise as high as they can over the southern tip of Spain, after which they “surf” above the sea at height before once again picking up the thermals over land in north Africa. ...
http://www.bbc.com/earth/story/20160321 ... bird-wings
The biophysics of bird flight: functional relationships integrate aerodynamics, morphology, kinematics, muscles, and sensors
Douglas L. Altshuler, Joseph W. Bahlman, Roslyn Dakin, Andrea H. Gaede, Benjamin Goller, David Lentink, Paolo S. Segre, and Dimitri A. Skandalis
Abstract: Bird flight is a remarkable adaptation that has allowed the approximately 10 000 extant species to colonize all terrestrial habitats on earth including high elevations, polar regions, distant islands, arid deserts, and many others. Birds exhibit numerous physiological and biomechanical adaptations for flight. Although bird flight is often studied at the level of aerodynamics, morphology, wingbeat kinematics, muscle activity, or sensory guidance independently, in reality these systems are naturally integrated. There has been an abundance of new studies in these mechanistic aspects of avian biology but comparatively less recent work on the physiological ecology of avian flight. Here we review research at the interface of the systems used in flight control and discuss several common themes. Modulation of aerodynamic forces to respond to different challenges is driven by three primary mechanisms: wing velocity about the shoulder, shape within the wing, and angle of attack. For birds that flap, the distinction between velocity and shape modulation synthesizes diverse studies in morphology, wing motion, and motor control. Recently developed tools for studying bird flight are influencing multiple areas of investigation, and in particular the role of sensory systems in flight control. How sensory information is transformed into motor commands in the avian brain remains, however, a largely unexplored frontier.
https://www.researchgate.net/profile/Ro ... 6735fa.pdf
Physiological, aerodynamic and geometric constraints of flapping account for bird gaits, and bounding and flap-gliding flight strategies
Aerodynamically economical flight is steady and level. The high-amplitude flapping and bounding flight style of many small birds departs considerably from any aerodynamic or purely mechanical optimum. Further, many large birds adopt a flap-glide flight style in cruising flight which is not consistent with purely aerodynamic economy. Here, an account is made for such strategies by noting a well-described, general, physiological cost parameter of muscle: the cost of activation. Small birds, with brief downstrokes, experience disproportionately high costs due to muscle activation for power during contraction as opposed to work. Bounding flight may be an adaptation to modulate mean aerodynamic force production in response to (1) physiological pressure to extend the duration of downstroke to reduce power demands during contraction; (2) the prevention of a low-speed downstroke due to the geometric constraints of producing thrust; (3) an aerodynamic cost to flapping with very low lift coefficients. In contrast, flap-gliding birds, which tend to be larger, adopt a strategy that reduces the physiological cost of work due both to activation and contraction efficiency. Flap-gliding allows, despite constraints to modulation of aerodynamic force lever-arm, (1) adoption of moderately large wing-stroke amplitudes to achieve suitable muscle strains, thereby reducing the activation costs for work; (2) reasonably quick downstrokes, enabling muscle contraction at efficient velocities, while being (3) prevented from very slow weight-supporting upstrokes due to the cost of performing ‘negative’ muscle work.
Bird flight is the primary mode of locomotion used by most bird species in which birds take off and fly. Flight assists birds with feeding, breeding, avoiding predators, and migrating.
Bird flight is one of the most complex forms of locomotion in the animal kingdom. Each facet of this type of motion, including hovering, taking off, and landing, involves many complex movements. As different bird species adapted over millions of years through evolution for specific environments, prey, predators, and other needs, they developed specializations in their wings, and acquired different forms of flight.
Various theories exist about how bird flight evolved, including flight from falling or gliding (the trees down hypothesis), from running or leaping (the ground up hypothesis), from wing-assisted incline running or from proavis (pouncing) behavior.
Contributed by Biker
Feathers and flight
Science Learning Hub
A bird is designed for flight. The combination of light weight, strength and shape, as well as precision control, is largely responsible for giving birds their special ability for sustained flight. Every part gives maximum power with a minimum of weight. The heavier the animal, the bigger its wings need to be. The bigger the wings, the more muscle is needed to move them. ...
https://www.sciencelearn.org.nz/resourc ... and-flight
Contributed by Biker
Pepper W. Trail
Senior Forensic Scientist / Ornithologist National Fish & Wildlife Forensics Laboratory Ashland, OR 97520
PURPOSE: Providing an introduction to the topography of the avian wing, to the form and function of wing flight feathers, and to the use of flight feathers for determining the minimum number of individuals (mni)
Everything You Need To Know About Feathers
Feather Anatomy: How Do Feathers Work?
Mya Thompson, Bird Academy. Illustrations: Andrew Leach, Jeff Szuc
Although feathers come in an incredible diversity of forms, they are all composed of the protein beta-keratin and made up of the same basic parts, arranged in a branching structure. In the most complex feathers, the calamus extends into a central rachis which branches into barbs, and then into barbules with small hooks that interlock with nearby barbules. The diversity in feathers comes from the evolution of small modifications in this basic branching structure to serve different functions.
Downy feathers look fluffy because they have a loosely arranged plumulaceous microstructure with flexible barbs and relatively long barbules that trap air close to the bird’s warm body. Pennaceous feathers are stiff and mostly flat, a big difference that comes from a small alteration in structure; microscopic hooks on the barbules that interlock to form a wind and waterproof barrier that allows birds to fly and stay dry. Many feathers have both fluffy plumulaceous regions and more structured pennaceous regions.
Everything You Need To Know About Feathers
Feather Function: What do feathers do?
Each feather on a bird’s body is a finely tuned structure that serves an important role in the bird’s activities. Feathers allow birds to fly, but they also help them show off, blend in, stay warm, and keep dry. Some feathers evolved as specialized airfoil for efficient flight. Others have been shaped into extreme ornamental forms that create impressive displays but may even hinder mobility. Often we can readily tell how a feather functions, but sometimes the role of a feather is mysterious and we need a scientific study to fill in the picture.
Everything You Need To Know About Feathers
Feather Growth: How do feathers develop?
Feathers are dead structures that cannot repair themselves when damaged. Because a healthy and functional coat is critical to survival, each year birds shed their old feathers and then grow a whole new set. This molting process is a carefully timed affair in which feathers are shed and regenerate in turn over a period of weeks so the bird can maintain its protective outer layer and ability to fly. Once the new set of feathers has matured, molt is complete and new growth only occurs before the next molt cycle when feathers are accidentally lost.
The growth process:
Cross sectional geometry of the forelimb (wing) skeleton and flight mode in pelecaniform birds.
Erin L. R. Simons, Tobin L Hieronymus, Patrick M. O'Connor;
Published in Journal of morphology 2011
Avian wing elements have been shown to experience both dorsoventral bending and torsional loads during flapping flight. However, not all birds use continuous flapping as a primary flight strategy. The pelecaniforms exhibit extraordinary diversity in flight mode, utilizing flapping, flap-gliding, and soaring. Here we (1) characterize the cross-sectional geometry of the three main wing bone (humerus, ulna, carpometacarpus), (2) use elements of beam theory to estimate resistance to loading, and (3) examine patterns of variation in hypothesized loading resistance relative to flight and diving mode in 16 species of pelecaniform birds. Patterns emerge that are common to all species, as well as some characteristics that are flight- and diving-mode specific. In all birds examined, the distal most wing segment (carpometacarpus) is the most elliptical (relatively high I(max) /I(min) ) at mid-shaft, suggesting a shape optimized to resist bending loads in a dorsoventral direction. As primary flight feathers attach at an oblique angle relative to the long axis of the carpometacarpus, they are likely responsible for inducing bending of this element during flight. Moreover, among flight modes examined the flapping group (cormorants) exhibits more elliptical humeri and carpometacarpi than other flight modes, perhaps pertaining to the higher frequency of bending loads in these elements. The soaring birds (pelicans and gannets) exhibit wing elements with near-circular cross-sections and higher polar moments of area than in the flap and flap-gliding birds, suggesting shapes optimized to offer increased resistance to torsional loads. This analysis of cross-sectional geometry has enhanced our interpretation of how the wing elements are being loaded and ultimately how they are being used during normal activities.
Fig. 7. Illustration of wing anatomy of (A) Morus bassanus (OUVC 10587) (the northern gannet), and (B) Pelecanus occidentalis (OUVC 10586) in ventral view. (C) Schematic of the distal forelimb skeleton and proximal feather attachments. The secondary flight feathers (shaded light gray in A and B) are oriented perpendicular to the axis of the ulna. The primary flight feathers are oriented obliquely to the axis of the carpometacarpus. Note also difference in mean chord length (width of wing) between species. Abbreviations: CMCmaj, major metacarpal; CMCmin, minor metacarpal.
https://www.semanticscholar.org/paper/C ... a15aaad3cc
Posted here: viewtopic.php?p=635938#p635938
The six degrees of freedom
(Translational motion is the motion by which a body shifts from one point in space to another.)
Moving forward and backward on the X-axis. (Surge)
Moving left and right on the Y-axis. (Sway)
Moving up and down on the Z-axis. (Heave)
Tilting side to side on the X-axis. (Roll)
Tilting forward and backward on the Y-axis. (Pitch)
Turning left and right on the Z-axis. (Yaw)
This very helpful video animation is about Roll - Pitch - Yaw
© Mark Wood
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