Governments support research and development (R&D) largely because there is a national need to support certain fields and types of research and there is a need for government to have their own sources of technical information and advice. In the UK, the fulfilment of these needs is met by several establishments. The First World War taught the Defence Services that if they were to keep ahead, or even abreast, of the fighting forces of other countries, they must maintain in peace time special organisations of a scientific or technical nature. As a result, each of the three Services set up experimental establishments staffed largely by professional scientists and engineers on full time permanent appointments. These establishments worked under severe disadvantages during the 1920s and 1930s because of economic crises (and therefore threat of severe reductions) and anti-defence opinion in academic circles.

The study of powerplant control systems is often carried out in isolation from the requirements of the aircraft. In this collaborative study a Systems approach has been adopted to ensure that the results obtained for an integrated control system are truly applicable to the combined system: airframe, avionics and powerplant with particular regard to the next generation of aircraft employing high technology in methods of data transmission, system integration and crew-system interfaces.

Ventilated wall jets have recently received the attention of some investigators, motivated by its important applications in aircraft industry. In practice, the boundaries of the flow are more apt to be rough than smooth. The purpose of the present work is to study the effect of surface roughness on the mean and turbulence characteristics of ventilated wall jets. Experiments were performed with a two-dimensional turbulent jet flow over a smooth surface and over rough surfaces at different grades of sand roughness.

The aerodynamic pitching moment, lift and drag forces acting on a ski-jumper during the free flight and landing phases were measured using scaled models in a wind tunnel. Comparisons are made between those meaurements and observations of actual ski-jumps.

It is shown that the high angles of incidence (typically α varies from 35° to 55°) adopted by ski-jumpers during free flight is determined by the need to prevent tumbling. Over this range of incidence angles, the opposing moments due to weight distribution and aerodynamic pressure distribution are approximately in equilibrium, and small out-of-balance moments can be accommodated by arm movements. The maximum lift/drag ratio on a ski-jumper in free flight occurs at α ≃ 25°. If it were possible to avoid tumbling at low incidence angles, maximum jump lengths would be achieved at α ≃ 8°.