RESULTS OF STRUCTURAL DYNAMIC TESTING OF THE XV-15 TILT ROTOR RESEARCH AIRCRAFT

The XV-15 tilt rotor research aircraft was designed, built, and tested by Bell Helicopter Textron (BHT) under a joint NASA/Army/Navy proof-of-concept program. The XV-15 tilt rotor research aircraft completed its initial development and flight envelope expansion flights on August 23, 1980, at the BHT Flight Research Center, Arlington, Texas. The concept evaluation flights are now underway at NASA Ames and Dryden Flight Research Centers, California. Aircraft Number 1 has accumulated 37 flights for a total of 18 flight hours. Aircraft Number 2 has completed 167 flights, 72 flight hours, and has been tested up to a maximum true airspeed of 301 knots (346 mph). The results of the structural characteristics obtained up to date will be presented. Discussion includes rotor and airframe loads, natural frequency placement, airframe control system interaction, wing-rotor-pylon aeroelastic stability , and dynamic modeling techniques used in analyses.