Some comparisons of turboramjet-powered hypersonic aircraft for cruise and boost missions.

Abstract

The results of a launch-vehicle mission analysis are presented and compared with those of a previous analysis of hypersonic transport missions. The launch vehicles studied consist of hypersonic aircraft first stages, which are powered by hydrogen-fueled, subsonic-burning turboramjets, and Ek-O? rocket second stages. A parametric investigation of the vehicle characteristics and the trajectory is presented and used to indicate the maximum payload capability of the launch systems. First-stage parameters that were varied include wing loading, fuselage slenderness ratio, wing thickness, and aspect ratio. Trajectory parameters that were varied include lateral-range requirement, cruise Mach number, and turn radius. Parameters examined that affect the staging maneuver include maximum normal acceleration, maximum allowable angle of attack, and dynamic pressure at staging. The parametric tradeoffs reflect the variations in fuel consumption caused by aerodynamic and propulsive efficiency changes and the variations in structural weight because of environmental heating and structural loading changes. The results indicate that launch vehicles are characterized by lower fuselage volumes and higher wing loadings than those associated with a hypersonic transport, but only small penalties result from using transport-like characteristics for the launch vehicles. Although the launch vehicle geometries and trajectories differ from those of a transport, the technology requirements are found to be similar.