I am stepping down as Editor-in-Chief of The Aeronautical Journal at the end of May. This was not an easy decision to make, as I have very much enjoyed being involved with the Journal over a period of some 15 years but it was time for a younger person with fresh ideas and fresh energy to take over the reins. My association with the Journal began in the early 2000s when the Editor at the time, Professor John Stollery, invited me to take over the Chair of a small editorial group that had been set up by Eric Rogers of the National Physical Laboratory to oversee the production and development of the Journal. The Group, which continues to meet monthly, consisted at the time of the Editor, the Chairman and key members of the Publications Department. In May 2005, the Group was strengthened by the arrival of Professor Mike Graham. Unfortunately personal reasons forced John Stollery to retire from the Editorship in December 2006 and he asked if I would take over the position. I agreed and Mike Graham then became the Chairman of the Editorial Group. More recently, the Group, which is now entitled the Editorial Committee of The Aeronautical Journal, was strengthened further by the appointment of Professor Chris Atkin as Deputy Chairman.

The synergistic combination of two promising engine architectures for future aero engines is presented. The first is the Composite Cycle Engine, which introduces a piston system in the high pressure part of the core engine, to utilise closed volume combustion and high temperature capability due to instationary operation. The second is the Intercooled Recuperated engine that employs recuperators to utilise waste heat from the core engine exhaust and intercooler to improve temperature levels for recuperation and to reduce compression work. Combinations of both architectures are presented and investigated for improvement potential with respect to specific fuel consumption, engine weight and fuel burn against a turbofan. The Composite Cycle alone provides a 15.6% fuel burn reduction against a turbofan. Options for adding intercooler were screened, and a benefit of up to 1.9% fuel burn could be shown for installation in front of a piston system through a significant, efficiency-neutral weight decrease. Waste heat can be utilised by means of classic recuperation to the entire core mass flow before the combustor, or alternatively on the turbine cooling bleed or a piston engine bypass flow that is mixed again with the main flow before the combustor. As further permutation, waste heat can be recovered either after the low pressure turbine – with or without sequential combustion – or between the high pressure and low pressure turbine. Waste heat recovery after the low pressure turbine was found to be not easily feasible or tied to high fuel burn penalties due to unfavourable temperature levels, even when using sequential combustion or intercooling. Feasible temperature levels could be obtained with inter-turbine waste heat recovery but always resulted in at least 0.3% higher fuel burn compared to the non-recuperated baseline under the given assumptions. Consequently, only the application of an intercooler appears to provide a considerable benefit for the examined thermodynamic conditions in the low fidelity analyses of various engine architecture combinations with the specific heat exchanger design. Since the obtained drawbacks of some waste heat utilisation concepts are small, innovative waste heat management concepts coupled with the further extension of the design space and the inclusion of higher fidelity models may achieve a benefit and motivate future investigations.

The current research paper describes the lateral-directional parameter estimation from flight data of a miniature Unmanned Aerial Vehicle (UAV) using Maximum Likelihood (ML), and Neural-Gauss-Newton (NGN) methods. An unmanned configuration with a cropped delta planform and thin rectangular cross-section has been designed, fabricated and instrumented. Exhaustive full-scale wind-tunnel tests were performed on the UAV to extract the form of aerodynamic model that has to be postulated a priori for parameter estimation. Rigorous flight tests have been performed to acquire the flight data for several prescribed manoeuvres. Four sets of compatible flight data have been used to carry out parameter estimation using classical ML and neural-network-based NGN methods. It is observed that the estimated parameters are consistent and the lower values of the Cramer-Rao bound for the corresponding estimates have shown significant confidence in the obtained parameters. Furthermore, to validate the aerodynamic model used and to enhance the confidence in the estimated parameters, a proof of match exercise has been carried out.

Vertical profile inefficiency caused by low-level flight segments during arrival and departure operations has a great impact on the financial cost of operators as well as negative environmental effects. In this regard, continuous descent and climb operations for arrival and departure phases are mostly preferred as one of the methods that reduce or eliminate vertical profile inefficiencies. In this study, focus is put on the arrival phase and the purpose is: (i) to analyse the vertical profiles of arrival traffic at Mugla Milas-Bodrum Airport (BJV), Antalya Airport (AYT) and Ankara Esenboga Airport (ESB) and to characterise the level-offs that occur in the arrival phase and (ii) to quantify the potential time, fuel and emission savings in the event of a shift of inefficient low-level flight segments to the cruise segment of equal distance. For the purpose of this paper, real-time flight data is used for the analysis of the vertical profiles of flights. Flight parameters, such as latitude, longitude, altitude, speed and so on are used to determine, visualise and characterise level-off segments. The Boeing Fuel Flow Method 2 is used to calculate emissions at any altitude. Analyses of the results show that 80%, 74% and 69% of arrival traffic at BJV, AYT and ESB, respectively. were exposed to at least one level-off lasting longer than 20 seconds and significant potential for time, fuel and emissions savings exist for three airports.

Unlike conventional ballistic parachutes, gliding parachutes have been extensively used as guided precision aerial delivery system (GPADS) platforms in recent years. The reasoning may be found in gliding and manoeuvering capabilities, which make this kind of ram-air parachutes superior for precision aerial delivery application. In contrast, wing-shaped configuration along with more design variables create a cumbersome design procedure for this type of parachute. Especially, when an affordable configuration is demanded, the design procedure will be a more important problem. In this respect, an innovative integrated design framework is proposed in which significant design aspects are considered so that the gliding parachute configuration can be optimiseoptimised through a bi-objective optimisation problem to find optimum cost for achievable gliding ranges. To do so, the configuration is defined with minimum required parameters and design space is constrained by performance and stability as significant design requirements to guarantee the feasibility of the solutions in practice. The objective functions are defined in terms of gliding characteristics and amount of materials for fabrication which are representative for maximum reachable stand-off distance and unit cost, respectively. As an effective numerical optimisation method, a niched multi-objective genetic algorithm (MOGA) is used to generate a pareto-optimal set for a specific payload mass whereas constraints are handled through a tournament selection process. Based on results, the provided pareto front can aid the designers in decision-making and trade-off between demanded objectives for a payload weight. The underlying design problem is solved using an all-at-once (AAO) approach and the design loop converges to favourable results in a reasonable time. Finally, as a comparative study, an optimiseoptimised affordable cargo parachute is proposed for the GPADS application in which the material cost is reduced by at least 25% with respect to an available low-cost gliding parachute with the same glide ratio.

Over the past decade, NASA, under a succession of rotary-wing programs, has been moving towards coupling multiple discipline analyses to evaluate rotorcraft conceptual designs. Handling qualities is one of the component analyses to be included in such a future Multidisciplinary Analysis and Optimization framework for conceptual design of Vertical Take-Off and Landing (VTOL) aircraft. Similarly, the future vision for the capability of the Concept Design and Assessment Technology Area of the U.S Army Aviation Development Directorate also includes a handling qualities component. SIMPLI-FLYD is a tool jointly developed by NASA and the U.S. Army to perform modelling and analysis for the assessment of the handling qualities of rotorcraft conceptual designs. Illustrative scenarios of a tiltrotor in forward flight and a single-main rotor helicopter at hover are analysed using a combined process of SIMPLI-FLYD integrated with the conceptual design sizing tool NDARC. The effects of variations of input parameters such as horizontal tail and tail rotor geometry were evaluated in the form of margins to fixed- and rotary-wing handling qualities metrics and the computed vehicle empty weight. The handling qualities Design Margins are shown to vary across the flight envelope due to both changing flight dynamics and control characteristics and changing handling qualities specification requirements. The current SIMPLI-FLYD capability, lessons learned from its use and future developments are discussed.

An intelligent decision-making method was proposed for airport bird-repelling based on a Support Vector Machine (SVM) and bird-strike risk assessment. The bird-strike risk assessment model is established with two exponential functions to separate the risk levels, while the SVM method includes two steps of training and testing. After the risk assessment, the Bird-Repelling Strategy Classification Model (BRSCM) was trained based on the expert knowledge and large amount of historical bird information collected by the airport linkage system for bird detection, surveillance and repelling. Then, in the testing step, the BRSCM was continuously optimised according to the real-time intelligent bird-repelling strategy results. Through several bird-repelling examples of a certain airport, it is demonstrated that the decision accuracy of BRSCM is relatively high, and it could solve new problems by self-correction. The proposed method achieved the optimised operation of multiple bird-repelling devices against real-time bird information with great improvement of bird-repelling effects, overcoming the tolerance of birds to the bird-repelling devices due to their long-term repeated operation.

The aim of this work is to investigate and quantify the latency on a Stewart Platform caused exclusively by a Classic washout filter. This washout filter is intended to recreate the sensations of motion caused by changes of translational and rotational acceleration that an aircraft can provide, due to changes in attitudes caused by external factors, and those caused by the pilot’s command. The input signal was generated by a FlightGear Simulator in order to obtain the specific forces and angular velocities of a Boeing 747 during a take-off procedure. These signals are then filtered by a washout filter and sent to the inverse kinematics of the movable platform, which will transform the aircraft motion sensations in platforms actuator position, thereby causing a certain signal delay. Experiments were performed in a Stewart Platform to obtain the latency caused by the mathematical modelling of the entire washout filter system. This latency are then compared to the latency caused by the control and dynamics of the platform’s actuators. Results indicate that the washout filter is the most responsible for the latency of the specific force signals to be reproduced by the platform in this experiment, and that the natural frequency and damping coefficient values must be properly estimated in order to optimise the total latency.