Technical Writing - Early Aviation

Technical Writing - Early Aviation

THE INVENTION and SOCIETAL IMPACT of AVIATION TECHNOLOGY

Background and History of the Invention:

Human beings have always fantasized about being able to fly, as is evident from ancient artwork as well as thousand year-old mythological stories and literary fables that preceded the age of aviation by millennia. Leonardo da Vinci produced detailed drawings of flying machines five hundred years ago, but the first known serious attempts at manned flight date back only to the wind-driven hot-air balloons of the late 18th century and to the experiments conducted by Otto Lilienthal a full century later, a little more than a decade before the Wright brothers demonstrated the first fully powered manned flight in their now-infamous first flight of their "Wright Flyer" in December of 1903 (SASM, 2007).

Because the strategic and tactical advantages of an aerial view of the land during wartime are so overwhelming, military theorists were quick to develop an interest in the military use of aviation. Already, manned flight had been used in battle as early as 1870, in the Franco-Prussian War (Jackson, 2003). Balloons were quickly proven ineffective in action over enemy territory because they are exceptionally vulnerable to ground fire.

However, they provided crucial vantage points for surveying large areas, especially of hostile territory (Jackson, 2003).

The first tactical use of powered aerial flight in warfare involved lighter-than air dirigibles and soon after the outbreak of World War I, Germany began hand-dropping explosive bombs on France and England from enormous hydrogen-filled Zeppelins. By that time, aircraft designers had spent the decade since the Wright brothers' first powered flight developing gasoline combustion engines to replace the bicycle gears that propelled the Wright Flyer in 1903. The major combatants all used piston and radial-powered biplanes for aerial recognizance missions, but the first offensive tactical aviation operations consisted of spotter plane pilots shooting at each other with pistols and dropping hand grenades from the air (Jackson, 2003; Yeager & Janos, 1986).

World War I pilots began rigging machine guns to their aircraft, but the spinning propeller precluded placing weapons directly in the pilot's line of sight and the various solutions such as positioning the guns above the pilot on the top wing introduced so much error in accuracy that it severely limited the effectiveness of first-generation fighter planes. Germany solved this problem with the interrupter gear that coordinated the firing of machine guns to the spin of the propeller to allow pilots to fire directly through the propeller without hitting it. By war's end in 1918, fighter aircraft had evolved into powerful machines capable of precision flying at nearly 200 miles per hour and both sides had already introduced the world to the wartime threat of strategic bombing of population centers during wartime (Jackson, 2003).

Military concerns would inspire the greatest increase in aviation development in between the First and Second World War, known in the industry as the "Golden Age" of aviation (Yeager & Janos, 1986; Jackson, 2003). Likewise, the civil and commercial aviation industries were born from the wartime equipment surplus and the availability of war-trained pilots for employment by the U.S. Postal Service and the first passenger airlines of the 1920s (O'Connor, 1995). Within barely two decades of World War II, both the United States and Soviet Union fielded supersonic jet fighters and achieved manned orbital space flight, both of which were, in no small way, still attributable directly to the wartime aviation development efforts of the Nazis. Today, civilian travel by commercial aircraft is a routine element of modern society and military aircraft technology is on the verge of becoming so complex and powerful that future generations of military aircraft may have to eliminate an on-board human pilot altogether (Leary, 2000). The fact that the entire history of modern aviation is hardly more than a century old may be the most fascinating aspect of powered flight. The Invention of Powered Flight:

Generally, aviation scientists have traditionally taught that the mechanism responsible for heavier-than-air winged flight is the Bernoulli Principle, after Daniel Bernoulli (1700-1782) who introduced the concept that describes the velocity of liquid through pipes of different size. According to the Bernoulli Principle, the lift provided by an aircraft wing is attributable to the fact that aircraft wings are shaped to curve on their top surfaces and maintain a flat surface on their lower surface. Bernoulli's Law suggests that the air molecules must travel faster over the curved wing surface, which reduces the downward force of air pressure from above. Since the upward forces of air pressure from the air passing below the wing becomes greater, the difference between those two forces is translated into lift (Garrison, 2008).

More recently, advanced analytical techniques not available to earlier generations of aviation designers have changed the formal understanding of the mechanics responsible for wing lift. Specifically, it turns out that most wing lift is actually provided by the angle of attack and that to the extent Bernoulli's Law applies to the equation, it may actually inhibit rather than assist lift (Garrison, 2008). Regardless of the underlying mechanism, nothing more than casual observation of soaring birds was necessary to demonstrate the functional efficiency of winged flight first proven experimentally by Lilienthal in 1891.

Whereas previous technological solutions to the problem of overcoming gravity for the purposes of manned flight relied on lighter-than-air gasses or gliding wings, the Wright brothers' aircraft design was the first to employ aerodynamic lift from horizontal wings and powered thrust together. Gliders like Lilienthal's employed aerodynamic lift in their wing surfaces but relied on wind gusts for power. The Wright brothers attached a propeller to their airframe that was designed to push air exactly the way naval ships of the day used propellers in the water. Their historic flight lasted only 59 seconds but flew nearly 1,000 feet at approximately 10 feet in altitude and demonstrated that, at least in principle, fully independent powered flight was possible (SASM, 2007).

The Evolution of Modern Aviation and its Impact on Society:

The unfortunate paradox that nothing promotes more rapid human technological advancement than warfare was true thousands of years before the birth of aviation and remains equally true of virtually all fields of science and technology. However, despite the unfortunate motive for the rapid evolution of aviation from the Wright Flyer to highly complex and powerful 21st century air and spacecraft in one century, the fact remains that modern aircraft have substantially transformed human life on earth in several major ways. Commercial aviation was the original mechanism of "globalization" and completely revolutionized modern business fifty years ago, long before that concept applied to the computer age. Previously, the only means of intercontinental transportation was via oceanic routes measured in days and weeks rather than hours. The strategic advantages in commercial business of rapid air travel in between geographically remote locations was almost as apparent as the strategic and tactical advantages already demonstrated in the context of military operations (O'Connor, 1995).