CH-54A Design and Operational Flight Loads Study
UNITED TECHNOLOGIES CORP STRATFORD CT SIKORSKY AIRCRAFT DIV
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An analytical and correlation study of predicted fatigue design data and operational flight loads data for crane-type helicopters was conducted to compare operational mission profiles with a design mission profile and to provide data for use in establishing structural design criteria for future Army helicopters. Flight loads and usage data for CH-54A helicopters operating in Southeast Asia were compared with CH-54A design data. The effects of gross weight and altitude on true airspeed were determined. Fatigue spectra were developed for six dynamic components, and fatigue lives were calculated for these components. These fatigue lives were compared with lives predicted during CH-54A design. Service histories for these components were reviewed, and it was found that none of the changes made in these components resulted from load conditions. Peak operational load parameters were compared with limit static design values. Recommendations were then developed to assist in establishing future crane helicopter fatigue design criteria.