Rotor Systems Research Aircraft Risk-Reduction Shake Test
Abstract
The NASA/Army RSRA is a flying test bed for in-flight investigation and verification of new helicopter rotor system concepts and technologies. A shake test and an extensive analysis of results were performed to evalute the possibility of and the method for dynamically calibrating the RSRA. The RSRA airframe was subjected to known vibratory loads in several degrees of freedom and the responses of many aircraft transducers were recorded. Analysis of the transducer responses using the technique of dynamic force determination showed that the RSRA, when used as a dynamic measurement system, could predict, a posteriori, an excitation force in a single axis to an accuracy of about 5% and sometimes better. As the analysis was broadened to include multiple degrees of freedom for the excitation force, the predictive ability of the measurement degraded to about 20%, with the error occasionally reaching 100%. The poor performance of the measurement system is explained by the nonlinear response of the RSRA to vibratory forces and the inadequacy of the particular method used in accounting for this nonlinearity. The RSRA shake test have revealed areas of concern for an RSRA dynamic calibration, and has pointed out weaknesses in the force-determination method.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1990
- Accession Number
- ADA226498
Entities
People
- J. B. Wellman
Organizations
- National Aeronautics and Space Administration