Hofstetter WINGS #5

3. What role did the helicopter play in the development of aviation technology?

The helicopter was a technology that emerged after the war. Unlike with the airplane, the helicopter was invented by several different people over a period of time, making it impossible to credit one person or date with the invention. Juan de la Cierva created the autogiro that operated with slow speed and a lack of airflow. Before and during World War II, the first practical helicopters ended the era of the autogiros. Igor Ivan Sikorsky of the United States set out to build a usable helicopter. By the end of 1941, the VS-300 was a success and Sikorsky flew his helicopter from Stratford to Wright Field in five days. America was immediately captivated by the invention of vertical flight. People thought of the helicopter as the personal transport of tomorrow. The fact that the helicopter could rise straight into the air and hover in one spot created opportunities for advancement in aviation technology. The helicopter could be used in the military and in urban and regional transportation. Charles Kaman brought the helicopter into the jet age. It was suggested that jet propulsion could solve some problems retarding the growth of vertical flight. Kaman used a turboshaft engine that drove the rotors through a transmission, setting the stage for light and powerful turboshaft engines. The appearance of the turboshaft-propelled helicopter was a revolutionary jump in performance and the most important turning point in the history of rotary-wing flight. The jet-powered helicopters had a huge impact on military operations, being used for search-and-rescue and medical duties. Helicopters were used to drop soldiers into battle. Rotary-wing flight now represents a significant portion of the international aerospace industry (pg. 464-476).

6. What was the status of general aviation following WWII in the U.S.?

Following World War II, many industry leaders felt they could tap a market for private aircraft and recapture the international market for airliners. Between 1937 and 1945 journals and magazines featured stories that suggested airplanes, autogiros, helicopters, and roadable flying machines might rival the automobile as the method of family transportation in the near future. A Department of Commerce official thought that private plane sales were the most logical field for postwar expansion of the aeronautical industry. Magazine articles had titles like, “Wings for the Average Man,” and “Planes for All.” The number of licensed pilots in the United States went from 31,000 in 1940 to 400,000 in 1947. The CAA offered commercial licenses to returning military aviators. Many major aeronautical firms entered the market of light aircraft.  The sale of light aircraft went form 7,700 in 1941 to 33,254 in 1946. It was in 1947, however, that the postwar boom collapsed. The market hit rock bottom in 1951 with only 2,302 general-aviation aircraft sold. Piper, Beech, and Cessna where left after the collapse. The leaders of aviation industry no longer dreamed of a mass market. Small airplanes cost a significant amount more than the average automobile. By 1980s, the treat of liability suits forced manufacturers to increase prices of airplanes, causing large-scale manufacture of light aircraft to almost cease in the United States. Private flying turned to home-built aircraft after 1945. Business aviation, however, flourished after the war. General-aviation sales doubled between 1959 and 1963 because of business and corporate flying (pg. 499-505).

7. What effect did the invention of the computer have on aviation technology?

During the 1930s faster aircraft encountered unpredictable problems. An aerodynamically induced vibration in the wing or tail could break an airplane apart. Theory was developed to calculate factors that would reduce the potential for this flutter, but the equations were so complex that a large number of people were hired to act as ‘computers’. A German aviation research organization looked into using an experimental computer in 1941. Aircraft manufacturers purchased ten of the first nineteen IBM general-purpose computers. The computer gave birth to computational fluid dynamics. Computers could be used to transform complex mathematical equations into accurate visual representations of fluid flow. Airplane design was transformed by computers to avoid the old method of using conceptual drawings, hundreds of sheets of blueprints, and hiring dozens of employees to produce drawings. Lofting previously did not allow such precision that would allow the factory to build a modern aircraft. In 1961, a MIT doctoral student started to work on a software program that would be capable of advanced graphics processing. Two years later, computer terminals replaced drafting boards. In the 1980s, CAD/CAM was developed to offer design that was precise enough to be used in the aerospace industry. Computers changed the way airplanes were manufactured. The desire to automate the production of elements required new tools. Controlled technology gave way to computer numerically controlled machine tools to control the cutting and shaping processes. Electrical discharge machining was developed to revolutionize the business of shaping metal. Lightweight, onboard computers were eventually developed to operate guidance and navigation. Eventually computers were applied to simulated reality and protect the nation from nuclear attack (pg. 511-522).