Book Description
The report presents the results of a two-phase research program consisting of (1) in-flight measurement of aerodynamic pressures and structural loads on a compound, rigid-rotor helicopter and (2) correlation of these data with theoretical results. Flight test data obtained in Phase I and recorded on an oscillograph were read on an oscillograph reading machine and were processed in an automatic data reduction program. This data processing consisted of integration of the pressure data to obtain the distribution of aerodynamic lift and pitching moments over the rotor blade, as functions of azimuth position. Airload and structural load data were harmonically analyzed. Output of the data reduction program was used in Phase II as input to the correlation program. The measured airloads were used to compute the theoretical bending and torsion responses of the blade. The measured torsion moments were used in the theoretical prediction of the airloads. The results of the applied theories are compared with the flight measurements.