Lateral-Directional Flying Qualities for Power Approach: Influence of Dutch Roll Frequency

摘要

The program was conducted to extend the previous lateral-directional flying qualities research at Princeton University to include the influence of Dutch roll frequency. Simulated carrier approaches were flown in a variable stability Navion airplane at a closure speed of 105 knots. An environment of moderate natural turbulence and the carrier's turbulent wake were simulated. All operations were conducted in daylight under visual flight conditions. Data in the form of pilot Cooper ratings and commentary were obtained for configurations having several combinations of Dutch roll frequency, Dutch roll damping, and dihedral effect. Some limited testing was conducted at different roll time constants. The results of the program established a range of Dutch roll frequency and dihedral effect considered to be the most acceptable for the carrier approach task in turbulence. Trends of pilot opinion rating were qualitatively established for departures of frequency and dihedral effect from their optimum levels. The factors contributing to the deterioration of pilot rating in these instances were found to be turbulence sensitivity in roll and yaw, a predominantly yawing Dutch roll mode, and heading control problems. Increased Dutch roll damping was found to improve the pilot rating of those configurations which were sensitive to turbulence in yaw and those which had a predominantly yawing Dutch roll mode. (Author)