The Pearl Harbor Attack(called Hawaii Operation or Operation AI by the Japanese Imperial General Headquarters – Operation Z in planning – and the Battle of Pearl Harbor) happened on Sunday December 7, 1941 ie 70 years ago. Here is a video of remembrance of the infamous day which dragged the United States of America into World War II:
The main rotor or rotary wing on the H-3 has five identical wing blades. Other helicopters may have two, three, or four blades. A typical wing blade is shown in figure 1-17. The rotary-wing blade is made of aluminum alloy, except the steel cuff by which the blade attaches to the rotor hub. The main supporting member of the blade is a hollow, aluminum alloy extruded spar, which forms the leading edge. The steel cuff is bolted to the root end of the spar. Twenty-three individual pockets constructed of aluminum ribs, aluminum channels, and aluminum skin covering are bonded to the aft edge of the spar.