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*† A study of some modular stream-traced hypersonic intakes is presented. These intakes capture a part of a known flowfield by replacing the streamlines that pass through the perimeter of a sector capture shape with solid boundary layer-corrected surfaces. Modules are combined to form an engine with circular external profile and with each intake module feeding a separate combustor. The intakes studied are derived from internally compressive, axisymmetric flowfields with either constant slope or constant pressure boundary conditions. The number of modules varies between three and six. Stream thrust averaging is used to determine equivalent one-dimensional flow for input to a scramjet engine cycle analysis. For a given contraction ratio, the full mass capture engine performance of the modular waverider intakes is comparable with the performance of isentropic spike intake designs when combustor skin friction is neglected. However the low wetted area of the modular combustor design has a significant advantage when combustor skin friction is considered. A four-module waverider intake model was built using stereo lithography and tested at Mach 7 in the University of Oxford gun tunnel, and was shown to be self-starting in QinetiQ’s High Density Tunnel at Mach 7. The stream thrust averaged properties were determined experimentally by measurement of axial force and mass capture. Schlieren photographs and surface pressure measurements are presented. Skin friction in the model isolator section was found to affect intake performance by increasing the amount of compression and reducing efficiency.

A study of re-expansion (REX) scramjet intakes is presented. REX intakes employ mixed externalinternal compression with the internal contraction fixed by starting requirements and a cowl aligned with the external flow to minimise intake drag. As a result of the starting limitation the captured flow is partially re-expanded, resulting in non-uniform flow at the intake exit. Stream thrust averaging was used to determine equivalent one-dimensional flow for input to a scramjet engine cycle analysis. Because of the very low cowl drag, engine performance increases with compression and thus optimum turning-angle appears to be at the limit for detachment of the internal cowl shock. An axisymmetric REX intake was built using stereo lithography and tested in the University of Oxford Mach 7 gun tunnel. The stream thrust averaged properties were determined experimentally from measurements of intake mass capture and axial force. The captured flowfield was verified by surface pressure measurements and Schlieren. Skin friction in the model isolator section was found to significantly affect intake performance, increasing the amount of compression and reducing efficiency. Starting characteristics were determined experimentally in QinetiQ’s High Density Tunnel.