A study was conducted to evaluate the 300,000-byte version of the C- 81 AGAJ74 helicopter simulation program's capability for prediction of performance, rotor dynamic loads, and stability for soft-in-plane hingeless rotor helicopters. Available test data were compiled for the BO-105 single-rotor helicopter to provide a basis for evaluation of computer program analytical results. Results indicated good correlation for trim and performance, and reasonable correlation for main rotor alternating flap bending moments. Poorer correlation was obtained for main rotor chord and shaft bending moments. Poor agreement was obtained for response to control inputs in hover and at 100 knots; this may have been due to selection of too large a numerical integration interval. Approximately the same damping was indicated by test and analysis for aeroelastic stability. Attempts to compare C-81 results for control power and stability derivatives with analytical results from Boeing Vertol's Y-92 computer program were not sucessful. Significant differences were attributed to restraint of blade flapping in C-81 during these computations.