From the first, let me nail my colours firmly to the mast by quoting Beethoven’s eventual dedication of the “Eroica” Symphony. For this particular Lanchester Lecture we are “to celebrate the memory of a great man”. My meaning here, I hasten to add, has none of that bitter intention of the Republican Beethoven who, so the story goes, having ripped out his earlier dedication to Bonaparte then substituted those words to commemorate the man once revered but who had recently proclaimed himself Emperor of the French. My intention is that we celebrate the memory of a man whose thinking remains as alive, as vital, as the day he set pen to paper. Each day of our lives we see his vision made manifest reality in the vapour trails of the Big Jets high overhead. And to borrow such a dedication seems appropriate since, not only was Lanchester a great admirer of Beethoven’s music, but also Lanchester’s largeness of spirit, his grandness of vision, his capacity for unremitting sheer hard labour put him in the heroic mould.

A general-purpose low turbulence wind tunnel was constructed using the design method of Bradshaw. Sound absorbent material was used in every four corners to decrease sound intensity produced by a fan. The longitudinal component of turbulence intensity at the centre of the closed working section is less than 0.02% of the mean velocity in the speed range between 18 m/s arid 53 m/s. The mean velocity variations across the working section are within ±0.1% of the mean velocity.

Performance measurements have been done at representative tunnel cross sections to clarify the behaviour of flow in the tunnel. This work differs from previous studies in the sense that emphasis is placed not only on velocity distributions, but also on turbulence intensity distributions at several cross sections of the tunnel.

The critical Reynolds number for a flat plate at zero incidence, Rec = 3.5 x 106, measured in a stream of the very low turbulence intensity of 0.016%, is larger than that reported by Schubauer and Skramstad.

The prime need to know Mach number in flight is likely to be for the efficient operation and control of air-breathing propulsion units. The errors incurred by the use of the analytical expressions, which have been developed for supersonic flight, are quantified and shown to be increasingly serious for speeds in excess of M = 5.5 approximately. Systems for calculating this parameter in flight are reviewed and compared. It is shown that three out of the four systems identified are capable, potentially, of registering Mach number to a good precision. In each case, to achieve optimum precision requires a good knowledge of ambient air temperature. Such knowledge is likely to be available from meteorological satellites.

A semi-inverse viscous/inviscid coupling technique for the calculation of compressible flows is presented. Euler equations in integral form are solved for the inviscid part and integral compressible boundary-layer equations in direct and inverse form are solved for the viscous one. Interaction is realised using the equivalent sources approach.

The technique has been applied to the calculation of the aerodynamic characteristics of aerofoils both in cruise and take-off or landing configurations. To treat the complex geometries involved in the latter case, a multi-block approach, based on structured ‘H’ grid topology, has been developed and validated for different configurations.