Before 1939, Canada's shipbuilding industry had been moribund for nearly two decades - no steel-hulled, ocean-going vessel had been built since 1921. During the Second World War, however, Canada's shipbuilding program became a major part of the nation's industrial effort. Shipyards were expanded and more than a thousand warships and cargo ships were constructed as well as many more thousands of auxiliary vessels, small boats, and other craft. A large ship-repair program also began.
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From the 1920s to the early1940s, the American Society of Mammalogists and the Ecological Society of America became involved in efforts to preserve natural conditions on protected land areas, and to conserve predatory and other wildlife. Members vigorously disputed how active a scientific society should be in advocating for conservation. Charles C. Adams and Victor E. Shelford served as leaders in two major efforts aiming to shape federal policy, notably the preservation of natural landscapes and the protection of predatory animals. Their unique argument for conservation highlighted preserved landscapes with their original compliments of wildlife, emphasizing the outstanding scientific value and potential for future scientific study of protected places. Through their work on committees of their professional societies and the National Research Council, Adams, Shelford, and many of their colleagues illustrate the various avenues utilized by scientists in efforts to preserve the very essence of their research. Scientific societies took risks as members and the organizations themselves played critical roles in conservation advocacy, while the politics of science became intermixed with the politics of nature preservation.
The Global War on Terror with specific emphasis on the recent military operation in Afghanistan has shown the invaluable contribution that heavy lift helicopters bring to the combatant commander. However, the flight range, altitudes and lift capability required to operate effectively in such an austere environment are pushing the limits of these helicopters. In an attempt to increase the operational capability of the CH-53E, this study will investigate methods for maximizing tail rotor effectiveness at high gross weights and high altitudes. This thesis records an analytical study designed to investigate the intricacies of tail rotor design and, by the computational simulation afforded through the Rotorcraft Comprehensive Analysis System (RCAS), define a tail rotor at high altitude that will reduce the tail rotor power required in hover by 10%. The versatility required of the tail rotor is seen due to the nature of the flow regime, which requires the tail rotor to effectively operate with inflow velocity from any direction, with a spanwise distribution of flow that produces Reynolds numbers up to 5.6e7 and with pilot commanded pitch changes from -10 to 24 degrees. With little to no assistance from the vertical fin, the tail rotor is most heavily relied on for antitorque response in hover; therefore, focus will be placed on hovering efficiencies tempered by solid forward flight and hover slide performance.
