Brief History of Aircraft Design As an additional aid in establishing the context for your study of aircraft design, consider briefly its history. This section will acquaint you with the most significant personalities, aircraft, and events in the history of aviation and aircraft design. As you read, note how aircraft designs were equally influenced by customer needs and available technology.Also note the profound influence aircraft designs have had on the recent history of the world. 1.1 Early Years Man’s early thinking about flying was undoubtedly inspired by watching and seeking to imitate birds. The first men to fly were probably Chinese, flying in large manned kites perhaps as much as two millennia ago. Kites are aircraft which generate lift from pressure changes as air flows pastthem, but which are tethered to the ground and rely on the wind to provide the necessary air flow. They were probably developed originally as toys, but some inspired ancient engineer recognized their military potential. Manned kites were developed to meet military needs for elevated platforms from which to observe their enemies. Kites may also have been used to drop soldiers or spies behind enemylines. In Europe, small kites were developed in the thirteenth and fourteenth centuries, but practical man-carrying kites were not used militarily until the early 1900s. Most Europeans who thought about manned flight imagined flapping-wing vehicles called ornithopters with human muscle providing the motive power. In the late fifteenth century, the famous artist Leonardo da Vinci made manysketches of such vehicles and the mechanisms needed to translate human arm and leg motions into the flapping of wings. Unfortunately, all of these dreamers and experimenters did not have sufficient knowledge of aerodynamics to do analysis to determine if a man could generate the power those vehicles would require to sustain flight. They also failed to understand the requirements for stability andcontrol. Though many man-powered ornithopters were built, none were successful. The first Europeans to fly were Francois Pilatere de Rozier and the Marquis d’Arlandes, who became airborne in a hot air balloon built by Etienne and Joseph Mongolfier in 1783 (Fig. 1.1). In the same year, Professor Jacques Charles and Marie-Noel Robert were the first to fly in a hydrogen-filled balloon. Balloons of bothtypes quickly became attractions at fairs and other public displays. Like kites, they were also adopted for military observation duties. When the advent of long-range artillery established the requirement for lofty vantage points from which observers could evaluate and correct the artillery’s aim, hydrogen-filled balloons were most commonly chosen. Balloons served in many nineteenth-century wars,including the FrancoPrussian War and the US Civil War. They were still used extensively as observation platforms in World War I and as obstacles to low-flying aircraft in World War II. Balloons were acceptable as fair attractions or tethered observation platforms, but potential customers who would use lighter-than-air vehicles for transportation required the ability to move in any desireddirection, even against the wind, at a reasonable speed. A vehicle with these capabilities was achieved by adding to a balloon or group of balloons a steering mechanism and a steam engine with a propeller. Such a vehicle is called an airship or dirigible. A French engineer, Henri Giffard, was the first to fly such a vehicle in 1852. Development of internal combustion engines soon provided airships withlighter, more powerful propulsion. Airships were used for passenger transportation and also as bombers in World War I. The German airship Graf Zeppelin flew around the world in 1929. It and the Hindenburg (Fig. 1.1)
made regular passenger flights between Europe and the United States until 1937, when the Hindenburg was destroyed by a hydrogen explosion.
Fig. 1.1 Mongolfiers’ first...
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