If the blade is set at the proper angle and made to move fast enough, the airflow will support the weight of the blade. The blade is designed so that the flow of air will be smooth and will conform to the shape of the moving blade. When a blade (airfoil) is moved through the air, a stream of air flows over and under it. When computing the chord line of this type of blade, an average or mean aerodynamic chord (MAC) becomes apparent as shown above. Since the curvature changes constantly in the CH-47 rotor blade, the result is that the chord of the blade also changes.
If the blade were symmetrical, then the chord line would be a straight line from the leading to the trailing edges. The rotary wing blade in a CH-47 is asymmetrical, that is it has a curvature that changes along the entire length of the chord. The distance between the leading edge and the trailing edge is known as the chord of the airfoil. The small tapering end is the trailing edge. As the diagram indicates, the thick end of the section is known as the leading edge. The term airfoil, as applied to the CH-47, refers to the rotary wing, and more specifically means the curvature, or camber, of the blade.Īs illustrated below, an airfoil section may be defined as the cross section of any surface producing lift. In a Chinook helicopter, the structure making flight possible is the airfoil - a surfaced body that responds to relative motion between itself and the air with a useful, dynamic reaction known as lift.
Click-N-Go Here to view a larger version. There are actually two whirl towers at this location, one is hidden behind the tree on the left. Rotor Blades are mounted on a head and then spun at normal operating speed (225 RPM) where data could then be collected and adjustments made to enhance their flying characteristics. August 2015: The Whirl Tower at the Boeing Factory in Ridley Park, Pennsylvania.
0 kommentar(er)
