Preliminary Evaluation of RSRA Data Comparing Pure Helicopter, Auxiliary Propulsion and Compound Helicopter Flight Characteristics

Up to this point, technical reports on the RSRA have focused on the concept itself and the development program. However, in the course of the development program, a large body of technical data has been acquired of general value to the rotorcraft technical community. Because of the unique features of the RSRA, much of this data represents the first of its kind to become available. In addition, the very extensive wind tunnel tests run on the RSRA during its design phase, combined with the available flight test data, provides perhaps the most comprehensive package of model and full scale data for correlation purposes available on any helicopter design. While these data will become significantly more interesting after the full calibration of the rotor load measurement systems is complete, the available data are of value in confirming the general capability of the RSRA aircraft to provide data of interest to the analyst/designer. It is the purpose of this paper to report on some of the more interesting data reduced to date and to stimulate industry interest in suggesting specific problems which can be studied on the RSRA. This is done in the context of comparisons of the three aircraft configurations flown in the qualification program - Helicopter, Aux Propulsion Helicopter and Compound Helicopter. A limited correlation of measured full scale data with wind tunnel model results and analysis is also presented. In general, it is shown that reducing main rotor lift and propulsive force requirements at high speeds is beneficial from performance, vibration and rotor dynamic loads points of view. The RSRA is shown to be fully capable of measuring component loads and thus of providing data useful to the designer for confirming his understanding of the system interactions present. Finally, correlation of model, analysis and full scale results appears reasonable.