Handling Qualities of Large Rotorcraft in Hover and Low Speed
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER
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This Technical Publication presents results that attempt to establish the fundamental relationships between rotorcraft size and handling qualities in the critical hover and low-speed flight regime. This research was conducted through a series of piloted handling qualities experiments on the NASA Ames Vertical Motion Simulator VMS and supported by other simulation analyses. Attitude Command-Attitude Hold ACAH and Translational Rate Command TRC control response types are systematically appraised using methodologies derived from the ADS-33 military rotorcraft handling qualities specification. ADS-33 provides a framework that exceeds any civilian requirements in terms of its ability to precisely quantify handling qualities and provide guidelines for good design. A rotorcraft of the scale and complexity of the LCTR2 concept will certainly need to incorporate such methodologies right from the beginning of its design lifecycle. In addition to assessing the impact of vehicle size on handling qualities, this document presents analysis of a piloted simulation study that investigates techniques for ameliorating the size-related issues. These include the use of a TRC control law that uses the additional degrees of control available in a tiltrotor such as the nacelles and twin rotors to enable maneuvering in translation with minimal fuselage attitude perturbations. There are technical feasibility questions pertaining to this approach, and the analysis also considers aspects of the control design that maintain the necessary handling qualities levels while minimizing the actuator demands, especially for the large nacelles.
- Military Aircraft Operations
- Commercial and General Aviation