The glancing interaction of a Prandtl-Meyer expansion fan with a supersonic wake is examined. The particular supersonic wakes of interest are the combustion wake generated by a vertical strut injected scramjet, and the side wall boundary layer of a supersonic wind tunnel. A physical structure for the interaction is defined, and an approximate analysis of the downstream behaviour of the wake is presented. The phenomenon of wake over-turning by the glancing expansion fan is introduced, based on this analysis. This over-turning produces a high pressure zone on the expansion generating surface, which for the vertical strut injected scramjet, is part of the thrust nozzle. Combustion wake over-turning is suggested to be a major thrust producing mechanism in this form of scramjet.

Pressure measurements were taken on the expansion generating surface of a glancing interaction involving the side wall boundary layer of a small supersonic wind tunnel. Results from the analysis presented were found to be consistent with these measurements.

In this paper a brief account of the optimal tracking problem (O.T.P.) is given, to show that the response of the output vector of a linear observable system can be made to be close to some desired dynamic response. This optimal tracking problem has been applied to linear mathematical models of the F-100 jet engine for various operating conditions, and the results obtained prove that it is possible to achieve the desired thrust response at each operating condition without violating the engine's operational requirements. An attempt was made to establish whether a single control law, based on the solution of the optimal tracking problem at one condition, could be used with the engine throughout its operating range.

An AGARD calibration model has been tested in the subsonic cryogenic windtunnel (KKK) of DLR Köln, model support interferences are calculated in the form of corrections to the aerodynamic coefficients. Two different model support systems are investigated: the model mounted on a horizontal sting (rear sting), and the model mounted on a vertical sting (ventral sting). Since for these configurations earlier experiments already exist, the corrections obtained are applied to these measurements for further verification. Furthermore the sting influences on the longitudinal static stability of the model are investigated in more detail.

A 3D-panel method is used which allows simultaneous calculation of several displacing and lifting bodies of nearly arbitrary shapes in the flow. The aerodynamic coefficients are obtained by numerical integration of the surface pressure distribution on the model.

The improved thin aerofoil method, which features extended expressions for lift and moment coefficients, is considered for further investigation and validation. The procedure to calculate the singularity coefficients is improved by using all aerofoil coordinates as control points in a least squares scheme. The classical NACA 0012 and NACA 65012 sections, the modern aviation aerofoil LS(1)—0417 and the extremely thick Kennedy-Marsden aerofoil are validated in place of the previously cited Karman-Trefftz aerofoil. This selection covers thickness ratios of up to 27·9%, camber ratios up to 7·69% and incidence up to 16·7°. Comparisons of velocity (or pressure) distributions and aerodynamic coefficients are made with two panel methods and with exact solution or experimental results whichever is available. Results indicated that the accuracy of the extended method is much better than expected and compares well with panel methods except for the extremely thick aerofoil. Additional results in the form of a systematic investigation of a weighted global error in the pressure distribution for the Karman-Trefftz aerofoils used in the previous study, are also included. Such an error shows similar trends and in many cases comparable magnitude to the errors generated by panel methods.