An analytical evaluation of the performance enhancement due to a servo-actuated trailing edge flap was carried out using the coupled rotor-fuselage model (CRFM). The performance enhancement from a trailing edge flap is achieved by introducing effective camber around the azimuth for a nominal aerofoil. An investigation on the best combination of flap parameters, namely the span, position, chord and deflection was carried out in order to identify an optimal configuration within given design constraints. The effects on vibratory control loads over a range of speed for a flap of 10% span, 20% chord, actuated at once per rev has expanded the retreating blade envelope for a Lynx aircraft by some 20kt. The flap hinge load was also examined and it was found not to be excessive. It was also confirmed that an actuated trailing edge flap does not have adverse effect on the pilot's control inputs to trim to a particular flight condition. This paper will discuss the aerodynamic enhancements derived from the application of the trailing edge flap and present conclusions drawn from this study.

In spite of the best intentions of many national and international funding agencies, much of the research and technology development (RTD) activity undertaken in Europe over the past few years has often been duplicating the work of others and has not resulted in an increase in capability in key areas. This is not to denigrate the work that has been undertaken — but have we done the right work? The EC-funded Thematic Network ‘Targeted Research Action in Aerospace Aerodynamics’, (TRA3), has been initiated with the broad aims of improving collaboration between existing EC- supported projects and, more importantly, attempting to put in place a long-term strategy for European aerospace aerodynamics RTD. TRA3 is, amongst other things, attempting to answer three key questions:

• What are the important aerodynamic technologies?

• What is the European aerospace industry’s current capability in these areas?

• In which areas should Europe be investing to maintain a competi tive aerodynamics capability?

The major benefit and output expected from TRA3 is the creation of a co-ordinated European aerodynamics RTD programme. The TRA3 Management Board consists of seven people who represent a cross-section of the European aerospace industry and research establishments, together with a Project Officer from the European Commission. This Management Board is tasked with formulating long-term plans for nine ‘Key Technology Areas’ that encompass all of the important aerodynamic technologies. This paper outlines the progress that has been made in meeting the very ambitious initial aims of the demanding work programme.

This paper examines the dynamic stalling of three wing planforms and characterises the main features of the stalling process in each case. The particular data were obtained during a three year research programme in the Department of Aerospace Engineering, University of Glasgow to collect high-resolution unsteady pressure data on the dynamic stalling characteristics of finite wing planforms. In this study, which was motivated by the pressing need for a greater understanding of the strongly three-dimensional effects in the tip region of helicopter rotors, the three wing planforms considered were a straight rectangular wing, a rectangular wing with swept tips and a delta wing. The initial test programme was followed by a further three years of detailed analysis and interpretation of the test data. Results from this analysis are presented in the present paper for cases in which the wings were subject to ramp motions.

Avionics Specialties in partnership with Honeywell has developed an integrated air data pressure sensor known as the integrated multi-function probe (IMFP). This continuously flow-aligned pressure-sensing device was developed using a multidisciplinary design approach encompassing computational fluid dynamic, (CFD), flow analysis, and experimentation. The computational investigation was performed using the finite element code, CFDesign, by Blue Ridge Numerics and consisted of pressure distribution studies for varying flows around conical sections. The application and integration of this technology to previously developed flow alignment and pressure transducing products lead to design similarity analysis saving considerable development time. Initial experimentation used to develop and refine the design and analysis consisted of laboratory bench testing, low and high-speed wind tunnel investigations, and subsonic flight-testing. Final performance verification was accomplished through data reduction and analysis of an extensive flight test program using a Lockheed Martin F-16 Fighting Falcon. The analysis, design and performance verification of this innovative pressure-sensing device was investigated for direct comparison to conventional Pitot-static performance with particular emphasis toward military fighter aircraft applications.

The operational requirements of modern combat aircraft demand complex engine intake and exhaust systems, capable of working efficiently over a very wide range of flight conditions and throttle settings. In addition to high aerodynamic efficiency and avoidance of high distortion levels at the engine face, these systems must also meet rigorous radar and infra-red signature targets. This paper discusses the implications from the aerodynamics point of view. Examples of technical approaches which seek to balance the sometimes conflicting requirements of aerodynamics and signatures are outlined. The potential offered by in-flight thrust vectoring to enhance flight performance and/or safety is also reviewed and the aerodynamic implications considered. Overall, propulsion integration for combat aircraft presents several challenges to the aerodynamicist, not least the development and validation of improved theoretical design methods capable of analysing the highly complex flows involved.

Kite design has recently seen a revival, with sports such as kite buggying and kite surfing becoming significant businesses in some countries. Since the aerodynamics of kites has not been explored in much depth this paper sets out to explain a major behaviour of kites, predicting where they will settle during flight. The analysis is confined to a vertical plane containing the kite string. It examines the basic forces for single-line or two-line kites and shows how the line azimuth angle(s) and equilibrium settling point(s) can be derived from the aerodynamic properties of the kite, from the kite mass and from the bridle lengths. It is noted that while several equilibrium points are predicted not all are stable equilibrium points. Wind tunnel tests with a specially built rigid model are described and these are shown to confirm theoretical predictions.

The design of an advanced flight control system (FCS) is a technically challenging task for which a range of engineering disciplines have to align their skills and efforts in order to achieve a successful system design. This paper presents an overview of some of the factors which need to be considered and is intended to serve as an introduction to this stimulating subject. Specific aspects covered are: flight dynamics and handling qualities, mechanical and fly-by-wire systems, control laws and air data systems, stores carriage, actuation systems, flight control computer implementation, flexible airframe dynamics, and ground and flight testing. The flight control system challenges and expected future developments are reviewed and a comprehensive set of references is provided for further reading.

International political and socio-economic developments have led the armed forces of many countries to become more aware of how their increasingly-stringent financial budgets are spent. One major expenditure for military authorities is upon aero-engines, because in-service deterioration in any mechanical device, such as an aircraft's gas-turbine engine, is inevitable. Each deterioration has an adverse effect on the performance and shortens the reliable operational life of the engine, thereby resulting in higher life-cycle costs. For a military aircraft's mission-profiles, the consequences of an aero-engine's deterioration upon the aircraft's operational-effectiveness as well as its fuel consumption and life have been predicted in this project using validated computer-simulations. These help in making wiser management-decisions, so leading to the achievement of improved engine utilisation, lower overall life-cycle costs and optimal mission effectiveness for squadrons of aircraft.

From Lanchester to the A380; from the era of the great pioneers to the integrated engineering teams and sophisticated analyses required to develop todays airliner. The ‘art’ of Aerodynamics has progressed a long, long way in the intervening century, but even with todays computational power it is still relevant to understand the basics and the early theories as developed by Lanchester and his contemporaries. In this lecture, the relevance of some of that early work and the compromises that must be made in optimising a modern wing design will be presented. These will include optimisation of spanwise loading, including trimming effects and winglets, and high and low speed aerodynamic and structural interactions, with examples drawn from the author's career in helping to develop the wings for the HS146 (now the RJX) and the Airbus family.

With the exponentially increasing computer power available over the last 30 years, the ‘art of compromise’ has progressively become the ‘science of optimisation’ and the lecture closes with a brief reference to techniques used to optimise current wing designs for the Airbus family.