A number of theoretical investigations have been conducted in the development of the design and analysis of advanced propeller configurations. Lock and Theodorsen as described by Davidson have been utilized to study counterrotating propeller systems. A different numerical method known as “SSTAGE”, which is an Euler solver for the Unducted Fan (UDF) concept, was used to predict the acoustic near field that compared well with experimental data. The NASPROP-E numerical analysis also consisting of an Euler solver has been used to theoretically study the near acoustic fields for the SR series propfan configurations. A counterrotating propeller test rig (CRPTR) was designed and built to obtain an experimental performance/acoustic data base for various propeller configurations for means of comparison with theoretical predictions.