Pilot-Induced Oscillation (PIO), although an old issue, still poses a significant threat to aviation safety. The introduction of new systems in modern aircraft modifies the human–machine interaction and makes it necessary for research to revisit the subject from time to time. Given the need of aircraft manufacturers to constantly perform PIO tests, this study analysed the feasibility of using three different computational pilot models (Tustin, Crossover and Precision) to simulate PIO conditions. Three aircraft models with different levels of propensity to PIO (original, low propensity and high propensity) were tested, as well as two pilot gain conditions (normal and high). Data were collected for a purely longitudinal synthetic task through simulations conducted in MATLAB®. PIO conditions were detect using a tuned PIO detection algorithm (ROVER). Data were analysed in terms of both whether the pilot models triggered a PIO condition and for how long the condition was sustained. The results indicated that the three pilot models only provoked PIO conditions when high gain inputs were applied. Additionally, Crossover was the only pilot model to trigger a PIO for the three aircraft models. There were also significant differences between the pilot models in the total PIO time, as the Tustin model typically sustained the oscillatory condition for longer.

In recent years, Performance Based Logistics (PBL) has been increasingly used to reduce the product lifecycle cost. As a result, the existing logistics analysis methods need to be reassessed due to the difference in PBL from the classical approach. This study considers the Spare Parts Allocation (SPA) and Level of Repair Analysis (LORA), which are the most commonly used problems within PBL, and are the subject of analysis. A comprehensive, multi-objective simulation-optimisation model is developed for a military aircraft operations case study, with the objectives of minimising total cost and maximising total flight hours. The Design of Experiment (DOE) method is used for determining simulation-optimisation parameters. Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method is used for the first time in order to select the best design points. Simulated Annealing (SA) was used for multi-objective optimisation with the SPA model being solved first. Then the LORA problem was added to this model as a decision variable and the effects of the integrated solution (SPA+LORA) were examined. The results show that the integrated solution yields remarkably better results in terms of flight hours and cost when compared to the SPA optimisation approach alone. Moreover, the proposed model provides a profit-centric approach and can be efficiently used as a decision support tool for both customers and suppliers for difficult and complex logistics support activities.

In this second Aeronautical Journal paper providing a technical appraisal of the Wright brothers' achievements, the authors use modelling and simulation and associated flight dynamics analysis to present the development of the first practical aeroplane. The aircraft in question, the Wright Flyer III, was deemed fit for service by the Wrights in October 1905, and had evolved significantly from the first powered aircraft of 17 December 1903. The appraisal tries to shed light on many of the flight handling problems that the Wright brothers faced during this, their third phase of aeronautical endeavour, in 1904 and 1905. They retained their unstable configuration born in the 1901 and 1902 gliders, gradually refining the performance and handling until they considered the aircraft was ready for market. Their process of refinement has been reconstructed in simulation within the Liverpool Wright project, highlighting the many important developments during a period when Wilbur and Orville's own documentation was limited. Apart from their engineering excellence, the Wright brothers are to be acknowledged for their perseverance and resolve in overcoming setbacks, for their ability to innovate and to recover and learn from their mistakes. In many ways the Wright brothers represent a model for the modern aeronautical engineer, and it is hoped that their legacy will be better preserved through the documentation of this project.

Air route networks can no longer meet operational efficiency requirements because of the rapid growth of complex traffic flows. Machine learning is employed to investigate the evolutionary mechanism of congestion in such networks in view of their high complexity and high density, and a reasonable network optimisation scheme is presented. First, deviations between nominal and actual routes are investigated with reference to radar track data, and a network reflecting actual route operations is constructed using adversarial neural networks. Second, flight time is used to characterise congestion in route networks. Actual network operations are considered, and congestion is defined from the perspective of road traffic engineering. The effects of the operational properties of traffic flows on flight times are analysed to establish various congestion indicators. A gradient boosting model is used to select indicator characteristics and analyse patterns in the variations of indicator values for each flight segment in distinct periods. The indicator–time relationship is leveraged to explore the evolutionary mechanism of congestion in the route network. Third, on the basis of this mechanism, a multiobjective optimisation model of congestion is formulated, and a particle swarm optimisation algorithm is executed to adjust the route passage structure, thereby solving the optimisation model. Finally, calculation validation is conducted using radar track data from the control sector of the Yunnan region. The average flight time in a route segment is 10% shorter in the optimised route network than in the nonoptimised route network, which confirms that the optimisation solution is practicable.

Air traffic controller training is highly regulated but lacks prescribed common assessment criteria and methods to evaluate trainees at the level of basic training and consideration of how trainees in fluence flight efficiency. We investigated whether there is a correlation between two parameters, viz. the trainees’ assessment score and fuel consumption, obtained and calculated after real-time human-in-the-loop radar simulations within the ATCOSIMA project. Although basic training assessment standards emphasise safety indicators, it was expected that trainees with higher assessment scores would achieve better flight efficiency, i.e. less fuel consumption. However, the results showed that trainees’ assessment scores and fuel consumption did not correlate in the expected way, leading to several conclusions.

In the development process of high-speed aircraft, the head of the aircraft is subject to high temperatures and high speed flows, supporting the maximum heat flow and thus requiring a reliable cooling system. A new type of head cooling system is proposed herein. An internal flow channel model of the heat transfer in a ball head made from high-temperature alloy steel is constructed, then an experimental platform is built to carry out relevant experiments on the performance of this cooling system. Firstly, the influence of different experimental conditions on the cooling efficiency of the ball head is studied. For given liquid-nitrogen supply pressure, a higher heating heat flux density on the outer surface of the ball head corresponds to higher cooling efficiency. Then, the vaporisation effect under different experimental conditions is evaluated using temperature sensors at the inlet and outlet of the ball head heat exchange channel in combination with images of the visualised glass tube. It is found that liquid nitrogen can vaporise completely when flowing through the heat exchange channel. The characteristics of the heating effect and liquid nitrogen injection for the ball head were evaluated using an infrared camera. Finally, under different experimental conditions of liquid-nitrogen supply pressure, it is found that liquid nitrogen can vaporise completely in each case, and the total temperature of the vaporised nitrogen is about 300K. It can thus be collected as a secondary gas source.

The objective of the present work is to estimate the performance of a turbojet engine during Fluidic Thrust Vectoring (FTV) employed by injecting the secondary-jet at the throat of a convergent nozzle. The nozzle performance maps and effective nozzle throat area obtained from experiments are coupled with the performance of a conventional engine (without FTV) using an iterative algorithm developed as a part of this work. The performance is estimated for different flow rates of secondary-jet sourced either from a separate compressor or the engine’s compressor. During FTV, the operating point shifted towards the surge line with increased turbine entry temperature. The desired and obtained vector angles and thrust magnitudes are different. At high secondary-jet flow rates, the turbine operation moved out of its performance map. These aspects should be incorporated while integrating the FTV at the system level, thus, asserting the importance of FTV studies coupled with engine performance.

The paper describes an “explicit” method of predicting the flow properties of a turbulent boundary layer; particular attention is paid to the region in which the growth of the layer is characterised by the decay of a velocity maximum. The validity of the method is tested against the data of Wieghardt and against new data of the present authors; it is shown to be satisfactory. The integral flow properties predicted by the method are used, together with a further assumption, to predict velocity profiles; these closely resemble the measured ones.

A methodology has been developed to integrate the vulnerability discipline into the conceptual/preliminary design process of combat aircraft. An interactive and programmable solid modelling Computer Aided Design (CAD) system is used to generate a CAD solid model of the aircraft’s critical components. The aircraft’s components’ sizes and shapes are pre-defined by a conceptual/preliminary design synthesis computer model. A systematic Child-Parent assembly process is used to model the aircraft vulnerability, by defining the criticality degree of each component in the aircraft assembly. Solid Modelling CAD techniques have been modified to develop techniques to perform the two main standard vulnerability assessments, namely the shotline and vulnerable area methods.

The design of guided missile systems presents a wide spectrum of problems to engineers in numerous disciplines which range through aerodynamics, electronics and signal processing. Of all the tasks involved in the design process, perhaps the most difficult is the integration of the various technologies into a complete, harmonised system. IMPACT is a computer program which was developed to address the system design aspects of homing guidance missile systems. The aim of this paper is to describe the engineering philosophy and theoretical background to the IMPACT program.

The equations of motion of many mechanical systems reduce to ordinary differential equations with time dependent parameters. A single degree of freedom system, with the damping and restoring forces varying with time according to the law … m (t+k)nhas been studied using the WKBJ approximation. The general solution of the differential equation can be used to arrive at the response of such time dependent systems, subjected to excitations which are specified to be of either deterministic or stochastic nature.

Seven years ago a paper on this same subject was read before the Main Society. This has been used as a basis from which to start.

It will be seen that great strides have been made in performance, and the projects in the Design Office and on the drawing boards particularly, would even satisfy parliamentary critics. In Derby, however, where jet lift was conceived, such things are well known. From the fuel system standpoint in general the changes in requirements have been routine, merely much greater fuel demands, greater altitudes and air speeds and hence, a greater range of fuel flow, and it is this which gives the fuel system engineer his greatest worries. Beyond this there is always the need for smaller and lighter units in fancy shapes.

Sir Henry Tizard’s work and–above all–his part in our survival in 1940–have been the subject of many memoirs since his death in 1959. The biography written by Ronald Clark at the invitation of Professor J. P. M. Tizard, Sir Henry’s eldest son, will shortly appear. This first Memorial Lecture of the Royal Aeronautical Society thus occurs when a full record of Tizard’s life is about to be made available, and there is therefore little point in the plain re-iteration of a condensed biography. Future Memorial Lecturers, as they inevitably grow more remote from personal contact with Tizard, may well choose to describe the advances of the future in those fields to which Tizard himself so notably contributed: science, defence, education and government. My purpose in this first Memorial Lecture is, therefore, to build a bridge between biography and those future fields in which Tizard’s example, although unlikely to be excelled, will be emulated and extended.

The paper presents a solution of the non-linear problem of the deformation of slender rectangular plates which are stiffened along their edges by elastically compressible stiffeners flexible in the plane of the plate. The webplate is assumed to be simply-supported along its contour. Numerical results showing the effect of flexural and normal rigidity of stiffeners are given for a square webplate loaded by shear and compression.

A few of the outstanding problems connected with the design of tailless aircraft are discussed. The paper does not set out to be in any way a comprehensive dissertation of the whole field of tailless design, as it was considered that it would be more useful to concentrate on some of the recent problems which are exercising the minds of designers at the present moment.

Since the problems discussed are those which are currently causing some degree of speculation, it follows that in the majority of cases only possible means of solution may be suggested and only tentative conclusions drawn.

If a plane oblique shock wave, inclined to the free stream at the angle ε, is produced in two-dimensional supersonic flow of Mach number M by (for example) a wedge which deflects the flow through an angle δ, the equation connecting these quantities may be written

In this form, δ is given explicitly when M, ε are fixed. Similarly, we may obtain M explicitly when ε, δ are fixed; equation (1) may be written (see, for example, Liepmann and Puckett, Equation 4.27)

A theoretical study is presented for the investigation of a potential-flow model for enhancing lift over a flat-plate aerofoil experiencing thin aerofoil stall. Rather than suppressing the leading-edge separation, flow is assumed to separate tangentially at the leading edge and made to reattach smoothly at the tip of a forward-facing fence joining the plate tangentially on its upper surface to avoid any unnecessary stagnated flow. The length of the fence and its location from the leading edge form two geometrical parameters. At any positive angle of attack, the resulting bounding streamline emanating from the leading edge and terminating at the tip of the fence is simulated by using suitable mathematical singularities subject to boundary conditions such as attaining a finite velocity at each critical point of the conformal mapping involved, and the condition of finite pressure gradient at reattachment, when applicable. Computational results from varying these two geometrical parameters indicate that the lift from each model is enhanced, as compared with the attached flow model around a simple flat plate and the original separated flow model by Kirchhoff.

For many space applications, such as communication, weather, military, and scientific experiment satellites scanning precise regions, it is necessary to maintain a satellite in a fixed orientation relative to the earth. Unfortunately, a correctly positioned satellite deviates with time from this preferred orientation due to perturbing environmental forces. This explains considerable interest in libra-tional stability study in recent times.

Among the numerous methods developed for librational control, a passive technique depending on the gradient of the gravitational field has gained attention. Depending on the orbital distance, environmental effects, such as, aerodynamic, radiation, and magnetic torques, become significant compared to the gravity-gradient restoring moment. A need to determine the influence of these disturbing forces is thus evident.

I was delighted and honoured to have been invited to give this lecture on the technical aspects of the Schneider Trophy and the world speed record attempts. Great Britain and Italy were the main contenders in the final and most exciting phase of the contest. As the Macchi aircraft were the most successful defenders of the Italian colours and, being myself the successor to Dr. Mario Castoldi, designer of the famous Macchi racers for the Schneider Trophy, I was very pleased to accept the kind invitation of the Society to give this lecture, especially in consideration of the fact that, as far as Macchi contribution is concerned, it was possible for me to collect first hand information directly from the people who actively collaborated with the racing effort.