At present, the lack of UAV regulations and standards precludes UAVs from being certified to operate commercially in un-segregated civilian airspace. Because of strategic, economical and security requirements, it is necessary to devise a method to operate UAVs in South African airspace within existing regulatory arrangements. This paper suggests specific UAV missions, viz; maritime patrol/boarder control, search and rescue, and cargo transport, together with design considerations and possible concepts of UAV; operations, maintenance and training, that will enable UAVs to satisfy the immediate South African strategic requirements whilst further UAV standards and regulations are being developed.

Missions envisioned for micro air vehicles may require a high degree of autonomy to operate in unknown environments. As such, vision is a critical technology for mission capability. This paper discusses an autopilot that uses vision coupled with GPS and altitude sensors for waypoint navigation. The vision processing analyses a horizon to estimate roll and pitch information. The GPS and altitude sensors then command values to roll and pitch for navigation between waypoints. A flight test of a MAV using this autopilot demonstrates the resulting closed-loop system is able to autonomously reach several waypoints. The vehicle actually uses a telemetry link to a ground station on which all vision processing and related guidance and control is performed. Several issues, such as estimating heading to account for slow updates, are investigated to increase performance.

This paper presents a comparison of linear and non-linear methods for the analysis of aeroelastic behaviour and flutter boundary prediction. The methods in question include NASTRAN and ZAERO, based on linear aerodynamics, and the non-linear coupled CFD-CSD methods RANSMB and PMB, developed at the Universities of Bristol and Glasgow respectively. The test cases used for this comparison are the MDO and AGARD 445.6 weakened wing. In general, it was found that the non-linear methods demonstrate excellent agreement with respect to pressure distributions, deflections, dynamic behaviour, and flutter boundary locations for both cases. This is in contrast to previous studies involving similar methods, where notable differences across the MDO span were found, and is taken to imply good performance of the CFD-CSD interpolation schemes employed here. While the linear methods produce similar flutter boundaries to the coupled codes for the aerodynamically simple AGARD 445.6 wing, results for the transonic ‘rooftop’ MDO wing design did not agree as well.

Experiments have been performed documenting the pressure field on the lee-side of a delta-wing at three incidence angles (5°, 10°, and 15°) and at Mach 1·8 using a PSP (Pressure Sensitive Paint) technique. The delta-wing model having a leading edge sweep of 60° was instrumented with 31 spanwise pressure ports at 68% of mean chord location. The Optrod-B1 binary paint was utilised and the PSP images were processed employing a resection based methodology. The comparisons of PSP results with those measured employing pressure taps show good agreement at different incidence angles.

The main objective of the paper is to evaluate the potential of reducing theenvironmental impact of civil subsonic aviation by using hydrogen fuel. Thepaper is divided into three parts of which this is Part II. In Part I thebackground, prospects and challenges of introducing an alternative fuel inaviation were outlined. In this paper, Part II, the aero engine design whenusing hydrogen is covered. The subjects of optimum cruising altitude and airportimplications of introducing liquid hydrogen-fuelled aircraft are raised in PartIII.

The study shows that burning hydrogen in an aero gas turbine seems to be feasiblefrom a technical point of view. If the priority is to lower the mission fuelconsumption, the results indicate that an engine employing increased combustoroutlet temperature, overall pressure ratio and by-pass ratio, seems to be themost attractive choice. The mission NOx emissions, on the other hand,seem to be reduced by using engines with a weak core and lowered by-passratio.

BAE Systems and the Engineering and Physical Sciences Research Council (EPSRC) have recently formed a partnership to invest in strategic research in aerospace and defence. The framework which has been developed as part of this new alliance places a strong emphasis on collaboration. This contrasts with the conventional approach to industry led research which is normally based on the establishment of ‘centres of excellence’ in specific subject areas. By using a collaborative approach, the funding partners aim to benefit from inter-disciplinary collaboration which will take place during the project, giving rise to a more effective use of the invested funds.

The objective of the research programme is to develop technologies which would support the design of low cost (both to acquire and operate) flapless unmanned aerial vehicles (UAVs). This work includes fundamental aerodynamic research to provide control forces without the use of conventional flaps, coupled with developments in the areas of control systems, manufacturing engineering, structural engineering, the electromagnetic behaviour of these structures and design optimisation. The output from the research has been extended to include the design, manufacture, assembly and flight of a demonstrator vehicle, which will provide the research teams with a platform on which to evaluate the performance of their technology in a realistic flight environment. A total of fourteen research groups at ten universities are involved in the five year programme, which has a total value of £6·5M (€9·75M).

In this paper, a mechanism of compressive fracture for elastic and elastic-plastic composite materials with interfacial adhesion defects is investigated. A classification of different approaches in modelling compressive response of layered materials is given. The analysis finds the upper and the lower bounds for the critical load. In order to achieve this, the problem of the internal fibre (layer) instability is considered within the scope of the exact statement based on the application of the model of a piecewise-homogeneous medium and the equations of the three-dimensional (3D) stability theory. The solution of the 3D problem is found for the most general case accounting for the bi-axiality of compressive loads. The characteristic determinants are derived for the first four fibre instability (microbuckling) modes, which are more commonly observed. Special attention is given to the calculation of critical loads for practical elastic and elastic-plastic layered materials.

Some in-service deterioration in any mechanical device, such as an aero-engine, is inevitable. As a result of experiencing a deterioration of efficiency and/or mass flow, an aero-engine will automatically adjust to a different set of operating characteristics; thereby frequently resulting in changes of rpm and/or turbine entry temperature in order to provide the same thrust. Rises in the turbine entry-temperatures and the high-pressure turbine’s rotational speed result in greater rates of creep and fatigue damage being incurred by the hot-end components and thereby higher engine’s life cycle costs. Possessing a better knowledge of the effects of engine deterioration upon the aircraft’s performance, as well as fuel and life usages, helps the users to take wiser management decisions and hence achieve improved engine utilisation. For a military aircraft, using a computer performance simulation, the consequences of low-pressure (LP) compressor’s deterioration upon an aero-engine high-pressure (HP) turbine blade’s life-consumption have been predicted.

PIV measurements in the near-field region of a jet flow emanating from a round synthetic jet actuator into quiescent air were conducted over a range of operating conditions. The primary purpose of this work was to investigate the nature of synthetic jets at different operating conditions and to examine the jet flow parameters that dictate the behaviour of synthetic jet actuators. The effects of varying diaphragm displacement and oscillatory frequency for fixed actuator geometry were studied. It was observed that the characteristics of synthetic jets are largely determined by the Reynolds number and stroke length. An increase in the former is observed to increase the strength of consecutive vortex rings that compose a synthetic jet, whereas an increase in the latter results in an increase in relative vortex ring spacing and for further increases in stroke length, shedding of secondary vortices. Correlations were also made between the operating parameters and the performance parameters most effective for flow control and which therefore determine the impact of a synthetic jet on an external flow. Relations of time-averaged dimensionless mass flux, momentum flux and circulation with the jet flow conditions were established and found to widely support an analytical performance prediction model described in this paper. It is anticipated that the experimental data obtained in this study will also contribute towards providing a PIV database for macro-scale synthetic jet actuators.

This work presents a method for selecting the gain parameters of a C* control law for an aircraft’s longitudinal motion. The design incorporates various handling quality requirements involving modal, time- and frequency-domain criteria that were fixed by the aircraft manufacturer. After necessary model order-reductions, the design proceeds in essentially two-steps: stability augmentation system (SAS) loop design and control augmentation system (CAS) loop design. The approach partly relies on the use of guardian maps to characterise, in each case, the set of gain parameters for which desired handling quality requirements are satisfied. The approach is applied throughout the full flight envelope of a business jet aircraft and yields satisfactory results.

The exits which passengers select in evacuation situations and the exits which are available post-crash is of great interest to aviation safety regulators who make rulings defining exit separation and aircraft evacuation certification, aircraft designers who develop the interior layout of aircraft cabins and position exits within the fuselage, cabin safety specialists who develop procedures for managing aircraft evacuation and cabin crew who must control aircraft evacuations. In this paper we examine issues associated with passenger exit selection behaviour and exit configurations frequently experienced during survivable crashes. This work makes use of the latest version of the Aircraft Accident Statistics and Knowledge database AASK V4.0, which contains information from 105 survivable crashes and over 2,000 survivors.