The Army Preliminary Evaluation of the YCH-47B helicopter was conducted by the US Army Aviation Systems Test Activity at Philadelphia, Pennsylvania in three phases during the period 1 March 1967 to 31 August 1967. The improvements in hover and level flight performance were defined and the change in flying qualities from those of the CH-47A helicopter were evaluated. An objectionable level of noise and vibration was encountered during testing; however, a significant reduction in vibration was achieved by the reduction of recommended rotor rpm from 230 to 225. An expansion of the 16,000 pound external load flight envelope to that of the helicopter with internal loads was substantiated with the exception of bank angle limitations. As a result of stress checks performed in turn maneuvers, the bank angle envelope was reduced to avoid excessive fatigue damage on aft rotor head control components. (Author)
Engineering Flight Test of the YCH-47B Helicopter Army Preliminary Evaluation I, II and III
1969
166 pages
Report
No indication
English