The unsteady load response in the frequency domain for a general two-dimensional body has been determined. Systems with one degree of freedom have been considered. The theory is based on the potential incompressible flow, and resolves around a mathematical treatment that starts from the theory of Drischler and Diederich. Admittance for the lift force and pitching moment (or side force and yawing moment for non lifting systems) has been calculated in closed form or numerically for aerofoils, swept back and swept forward wings, delta wings, and some ground vehicles (various car shapes) using sinusoidal and square gusts. Simulations have been performed for a wide range of gust speed ratios. The general features of the admittance function are discussed. It is proved that for some geometries there is an large number of frequencies that yield critical damping. These frequencies are generally very high. Comparisons with existing experimental data are good in the whole range of practical frequencies.

Unmanned aerial vehicles (UAV) have seen a rapid growth in utilisation for reconnaissance, mostly using single UAVs. However, future utilisation of UAVs for applications such as bistatic synthetic aperture radar and stereoscopic imaging, will require the use of multiple UAVs acting cooperatively to achieve mission goals. In addition, to de-skill the operation of UAVs for certain applications will require the migration of path-planning functions from the ground to the UAV. This paper details a computationally efficient algorithm to enable path-planning for single UAVs and to form and re-form UAV formations with active collision avoidance. The algorithm presented extends classical potential field methods used in other domains for the UAV path-planning problem. It is demonstrated that a range of tasks can be executed autonomously, allowing high level tasking of single and multiple UAVs in formation, with the formation commanded as a single entity.

The results of an investigation into the effect of both the number of orifices and the geometry of these orifices on the fluid structures exiting from a synthetic jet actuator are presented. The experiments have used smoke and laser visualisation and single hotwire measurement techniques to establish the flow field exiting the various orifices and the fluid velocities in the exit plane of the orifice. The results indicate that the use of two small orifices can perhaps produce two coherent vortex rings with a total circulation greater than that found in the ring produced by a large, single orifice of equivalent area. However, they have also shown that there are three different types of interaction between two adjacent orifices, related to the spacing between them and the level of excitation applied to the diaphragm. In addition, these interactions may affect the overall level of circulation in different ways. Finally the results have shown that a rectangular orifice of a given exit plane area is more likely to produce a turbulent ring than the equivalent circular orifice due to a ‘smoothing’ process which endeavours to create an axisymmetric ring from a non-axisymmetric slug of fluid. This work has shown that when using synthetic jet actuators in flow control applications, care should be taken in selecting the spacing and geometry of the orifices used, as certain set-ups may be more suited to certain applications than others.

Heat transfer levels have been investigated behind a rearward-facing step in a superorbital expansion tube. The heat transfer was measured along a flat plate and behind 2 and 3mm steps with the same length to step height ratio. Results were obtained with air as the test gas at speeds of 6·76kms-1 and 9·60kms-1 corresponding to stagnation enthalpies of 26MJ/kg and 48MJ/kg respectively. A laminar boundary layer was established on the flat plate and measured heat transfer levels were consistent with classical empirical correlations. In the case of flow behind a step, the measurements showed a gradual rise in heat transfer from the rear of the step to a plateau several step heights downstream for both flow conditions. Reattachment distance was estimated to be approximately 1·6 step heights downstream of the 2mm step at the low enthalpy condition through the use of flow visualisation.

Work has been carried out by Kutschera on how to assess, at the conceptual design stage, the performance of fighter aircraft. As part of this work, Kutschera reviewed a number of existing and proposed metrics for assessing aircraft performance. Reference 4 also describes how the performance of an aircraft can be quantified by three types of metric. The first type are steady state or point performance metrics, such as turn rate plots and energy manoeuvrability diagrams. The second type are manoeuvrability metrics and the last are agility metrics.

At 14h42 UTC (3.42pm BST), on Tuesday, 25 July 2000, Concorde F-BTSC, operated by Air France, started its take-off roll on runway 26 Right at Paris Charles de Gaulle, to undertake a charter flight to New York with nine crew and 100 passengers on board. Shortly before rotation, the front right tyre of the left main landing gear ran over a strip of metal, which had fallen from another aircraft, and was damaged. Debris was thrown against the bottom wing surface leading to a rupture of tank five. A major fire, fuelled by the massive leak, broke out almost immediately under the left wing. Problems appeared shortly afterwards on engine two and for a brief period on engine one. The aircraft took off. The crew shut down engine two following an engine fire alarm. The landing gear would not retract. The aircraft flew for about one minute at a speed of 200kt and an altitude of 200ft, but was unable to gain height or speed. Engine one then lost thrust, the aircraft’s angle of attack and bank increased sharply. The thrust on engines three and four fell suddenly. The aircraft crashed onto a hotel at Gonnesse. Everyone on board and four people in the hotel were killed.