Black Hawk Helicopter Vibration Analysis Due to Main Rotor Damage, Directional Constituents of the Resultant Vibrations

Report No. ARL-TR-2442
Authors: Joseph C. Fries
Date/Pages: March 2001; 27 pages
Abstract: Black Hawk helicopter cockpit vibrations due to main rotor damage are presented based upon an analysis and computer code originally developed in-house in the Air Systems Branch (ASB) of the U.S. Army Research Laboratory (ARL). Ballistic damage is simulated by removing various amounts of the outer radius of one blade of the rotor set of four blades. This simulated blade damage causes the rotor to be unbalanced allowing undesirable vibrations to be transmitted into the fixed-system airframe. This work considers the longitudinal, lateral, and vertical cockpit amplitude and phase components of the vibrations that make up the total vector vibrations that a cockpit occupant would feel. If the vibrations are severe enough, they could lead to attrition of the aircraft. This vibration data can be used in conjunction with historical human-vibration-tolerance data for later work toward determining a pilot's capability to function in the helicopter cockpit vibration environment.
Distribution: Approved for public release
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Last Update / Reviewed: March 1, 2001