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Despite being high-school drop-outs, the Wright brothers, Wilbur (1867–1912) and Orville (1871–1948), had sharp minds and mechanical aptitude, which they first displayed in the design of a printing press in the late 1880s and later as bicycle shop owners in the early 1890s. Their knowledge of mechanics grew, not from a formal education in engineering, but from self-study and practical, hands-on experience. This, combined with their fascination with flying, set the stage for the world to change on December 17, 1903. On the easternmost shores of North Carolina, on the sands of Kitty Hawk, the two brothers displayed and flew the first human-controlled and motorized airplane.
Man's Perennial Fascination with Flight
Bygone generations would have envied their achievement. From ancient times, man has had the desire to fly. Naturally, the first experimenters in aviation looked to birds for instruction and ideas. In the fifth century b.c., the Greek Archytas is thought to have made a "flying" bird-shaped device that was propelled by steam or a puff of air. Other bird-like artifacts, which may be the results of efforts to produce apparatuses with some sort of flying capability, have been unearthed in such diverse places as Egypt and South America. In the sixteenth century, Leonardo da Vinci wrote a Codex on the Flight of Birds, in which he recorded his observations of bird-wing design and his ideas for copying this design in the construction of a flying machine. He was, however, never able to do so successfully.
When the Industrial Revolution took off in the 1870s, great strides were made in the development of sophisticated engines, mechanical devices, and machines. The airfoil wing was engineered in the early nineteenth century, but it took another century for the availability of lightweight materials to converge with the foresight and creativity of the Wright brothers, culminating in their day of historic triumph.
Nowadays, engineers study aerospace design for years. Aircraft are designed and manufactured for a multiplicity of purposes, and vary greatly with respect to their shape, speed, size, and range. Yet in the development of all our different kinds of modern aircraft, we still take inspiration from birds, as well as from flying and gliding mammals, reptiles, and insects.
Inspiration Derived from Birds & Animals
The earliest aircraft wings, just like modern ones, use a wing design based on the airfoil-shaped wings of many birds. Such a wing's leading edge is thick and rounded, and it tapers down to a thin trailing edge. Upward-flowing air is cut over the leading edge, following the curved top surface. The air on top of the wing travels farther and faster than the air on the flat or indented lower surface. An upward force is generated by the greater air speed on top, creating a lower air pressure. On the lower surface, the pressure is greater, while the air speed is slower. Thus a fast gliding bird or aircraft is buoyed upward.
Engineers copy other features of bird-wings as well. Some birds have an outcropping feather group on their wings' leading edge, which is called the "alula." This alula helps minimize turbulence and stabilizes the flight of low-speed gliding birds. Aircraft have been engineered with a similar structure called the "Handley Page slot" or the "leading edge slot" to help prevent stalls.
Moths are also contributing to modern aircraft technology. For example, when searching for a mate, the male gypsy moth tracks the female by navigating along her pheromone plume. Researchers are using this concept to design drones that can follow artificial signature odors.1 Another moth, the hawk moth, is be-ing studied for its methods of regaining flight control in windy and whirlwind conditions.2
The flight of birds in flocks is also inspiring design, with engineers developing algorithms to guide the flight of teams of drones so they can participate together in search and rescue operations.
Vertebrates like flying squirrels, flying fish, and flying snakes are also making their contributions to aircraft design. Their ability to use their aerodynamic bodies to extend their jumping range has inspired the creation of the "jumpglider," a craft with an aerodynamic shape and a spring-based mechanical foot that propels it into the air. This capability allows the "jumpglider" to navigate around obstacles and over rough terrain. It can also operate in low-power situations.3
Pondering the Source of Biological Design
It is natural to ponder the source of these exquisite biological designs. Shape defines function in many respects; the wrong shape leads to the wrong function―or even worse, to no function at all. We all know that one poorly designed part on a gadget can cause the failure of the entire device. Engineers understand that successful function depends upon highly specified shapes and sizes for all the components of a mechanism—whether it's a mousetrap or an airplane.
However, here is the puzzle. It took human beings centuries' worth of accumulated effort, learning, creativity, and ingenuity—not to mention trial and error—to produce a functional, manned aircraft. Yet, according to Darwinian evolution, the original designs in nature that were mankind's inspiration for the design and construction of aircraft came into existence by a mindless process over eons of time. In other words, there was no intelligence or ingenuity behind the design of a bird's wing, but it required considerable intelligence and ingenuity to produce a mechanical version of it.
Many scientists, of course, continue to hold to Darwinian evolution because they have a prior commitment to philosophical materialism. For them, enough genetic mutations occurring over a long enough period of time can account for the diversity of designs and functions that we observe in the creatures in the natural world.
Others, however, are becoming skeptical of Darwinism. They note, for instance, that the mechanism of natural selection only favors the best-working among already existing creatures to fill a particular biological niche. Though adaptive changes have been observed in such characteristics as coloring, beak size, and antibiotic resistance, these changes can generally be attributed to internal genetic switches and genetic diversity within a given population.
Moreover, most genetic mutations are degenerative or harmful to a biological system, and such beneficial changes as do occur tend to be small and peripheral relative to the overall design. They would not affect the core structures that govern a complex function, like a creature's ability to fly. Hence, a more adequate explanation for complex biological design is needed.
While controversial, it is not arbitrary to see biological design as coming from intelligence. In our common human experience, even simple machines only come into existence when an engineer, scientist, or other individual uses his mind to conceive, develop, and execute a design. It stretches credulity to assume that the efficient and amazing biological designs that inspired man-made aircraft, and offered solutions for such complex functions as take-off, obstacle avoidance, stabilization, and landing optimization, came about merely by chance. For the origin of these superior biological designs, it is reasonable to posit a superior designer. •
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