The design of a thrust chamber for a rocket propulsion system is a challenging task. The thrust chamber has to be designed for minimum structural weight with an adequate factor of safety. This calls for a thorough knowledge of various structural loads, both internal and external, and the behaviour of the structure in flight. This paper presents the design and structural analysis of a pressure vessel used as thrust chamber for a rocket propulsion unit. The effects of kinetic heating, thermal stress, spinning and various aerodynamic loads and their mutual interactions are accounted for in this analysis. Based on a detailed stress analysis of the components and a modal/structural dynamic analysis of the flight vehicle as a whole, in which the thrust chamber is the main load bearing member, the required mechanical properties of the thrust chamber are obtained.

The long-running debate between the US and the EU over government supports for large commercial aircraft has recently boiled over into a major dispute involving the World Trade Organisation (WTO). While the two sides have currently backed off from what could be a very damaging WTO outcome, there are still wide differences over the legitimacy of government supports (direct or indirect) for Airbus and Boeing airliners. This paper:

1. • Describes the background to the current dispute.

2. • Analyses the 1992 US–EU Agreement on Large Aircraft Subsidies.

3. • Outlines the WTO Agreement on Subsidies and Countervailing Measures and the decision by the US to mount an action under the WTO complaints procedures against launch investment for Airbus and the EU’s counter claim against Boeing.

4. • Considers the precedents set by the WTO rulings on the Brazilian–Canadian dispute over regional jet supports.

5. • Summarises the US–EU complaints to the WTO.

6. • Considers potential outcomes and the implications for the civil aerospace industry on both sides of the Atlantic.

7. • Analyses the wider issues surrounding government intervention in the aerospace sector.

The paper views the dispute as a reflection of fundamental differences, based primarily on divergent economic doctrines and values, between the US and the EU states. There could be especially damaging consequences for the EU should the WTO rule against the systems of repayable launch investment used by the Airbus governments. But both sides could lose heavily from the affair and there is a good case for maintaining some form of direct government intervention in civil aerospace technology acquisition, even near market research, in support of environmental sustainability objectives.

Thermopile sensors detect electromagnetic radiation as a function of the object’s temperature. Because there is a temperature difference between the cold ground and the warm sky, these sensors could be used to detect the horizon and thus be used as a reference to stabilise a small aircraft, such as an unmanned aerial vehicle (UAV) in visual meteorological conditions (VMC). To verify this hypothesis, a system has been developed providing horizon detection using thermopile sensors to stabilise an R/C model aircraft. The aircraft has gone through a number of flight trials using remote control to enable and disable the stabilisation system. During the flight trials the aircraft was set at various attitudes when the system was enabled. The stabilisation system was able to assume wing level under various bank angles and weather conditions with minimum overshoot and oscillation.

Although the system shows good performance during flight trials, most of the original design was done using trial and error. A design tool was needed to implement further improvements to the system and to efficiently implement it on other aircraft. This required a good understanding of the physical behaviour of the system and the interaction between the sensors, aircraft and the environment. A mathematical model of the overall system was developed using the MATLAB/Simulink environment to simulate the behaviour of the system under various conditions. The simulation results were then compared with actual flight experiments. This paper describes the modelling techniques used for the different system components and the results of the simulation compared to actual flight trials.

An experimental investigation was performed to study the effects of surface roughness on the Mach 8·2 hypersonic turbulent shockwave–boundary-layer interaction characteristics of a deflected control flap configuration. In particular, the surface pressure and heat transfer distribution along a quasi-2D ramp compression corner model was measured for flap angles between 0° and 38°, along with a Schlieren flow visualisation study. It was found that surface roughness, of scale 10% of the hinge-line boundary layer thickness, significantly increased the extent of the interaction, while increasing the magnitude of the peak pressure and heat flux just aft of reattachment. The incipient separation angle for a fully turbulent, Mach 8·2 boundary layer with a hinge line Reynolds number of 1·44 × 106, was estimated at 28-29°, reducing to between 19-22° with the introduction of laminar sub-layer scale surface roughness.

Avoiding collisions with other aircraft is an absolutely fundamental capability for semi-autonomous UAVs. However, an aircraft avoiding moving obstacles requires an evasive tactic that is simultaneously very quick to compute, compatible with the platform’s flight dynamics, and deals with the subtle spatio-temporal features of the threat.

We will give an overview of a novel prototype method of rapidly generating smooth flight-paths constrained to avoid moving obstacles, using an efficient trajectory-optimisation technique. Obstacles are described in terms of simple geometrical shapes, such as ellipsoids, whose centres and shapes can vary with time. The technique generates a spatio-temporal trajectory which offers a high likelihood of avoiding the volume in space-time excluded by the predicted motion of each of the known obstacles. Such a flight-path could then be passed to the aircraft’s flight-control systems to negotiate the threat posed by the obstacles. Results from a demonstration implementation of the collision-avoidance technique will be discussed, including non-trivial scenarios handled well within 100ms on a 300MHz processor.