Robust sonic boom reduction in primary boom carpet

Japan Aerospace Exploration Agency has conducted a low-boom design for a small-sized (about 50 passengers) supersonic airliner. In this study, sonic boom loudness is evaluated in a primary boom carpet, while the focus boom is not considered. Two geometries having different robustness with respect to loudness distribution in a primary boom carpet are designed. One is designed considering only a cruise Mach number, and sonic boom loudness is reduced at both under-track and off-track positions. The other is designed considering both cruise and off-design Mach numbers, and the maximum sonic boom loudness in a primary boom carpet is minimized. In this paper, design examples to achieve low-boom characteristics at both under-track and off-track positions are reported. In addition, a low-boom design concept using canard is proposed to minimize the maximum sonic boom loudness in a primary boom carpet. Finally, differences of loudness distribution in a primary boom carpet between two geometries are discussed.