The purpose of this paper is to describe an approachwhich performs data fusion on the output ofmultiple, spatially separate, sensors engaged in thereal time tracking of obstacles in a helicopter'senvironment. The generated information can be usedeither as a flight director aid or as feedbackrequired by an automatic collision avoidance system.Obstacle track estimation has been commonly carriedout using the Kalman filter (KF) for linearestimation, or the extended Kalman filter (EKF) foruse on nonlinear problems. However, certainassumptions made in the derivation of the EKFalgorithms render it sub-optimal for aerial obstacletrack estimation. Additionally, the EKF has problemswith initialisation and divergence (stability) formany non-linear processes.

Research at the University of Southampton hashighlighted a link between fuzzy networks andassociative memory neural networks. This link isimportant as it allows new learning rules to bedeveloped for training fuzzy rules, and learningconvergence to be proved. This paper exploresmethods of fusion of estimates using neuro-fuzzymodels, and addresses some of the weakness of theKalman filter approximation introduced by theassumptions made in its derivation.

This paper proposes a correlation which attempts torelate an aerofoil's low speed dynamic stall onsetincidence to particular parameters describing itsstall behaviour in steady conditions. Theseparameters, which can be derived from experiment orpredictive algorithm, are the incidence of steadystall and a term related to trailing-edge separationcharacteristics. The correlation is based on a largeamount of data obtained from a number of aerofoilsbroadly classified into two families: the NACA fourdigit series of symmetrical sections and a family offour profiles with the NACA 23012 as the genericshape.

The correlation has been extended to low pitch ratesoutside the “deep” dynamic stall range and, whilstit pertains to stalling under ramp motions, a linkhas been established with oscillatory motions. Thepotential of the correlation is demonstrated by itsapplication to the design of a symmetric aerofoilfor use on wind turbines.

This paper reviews the status of aerospace materialscurrently under development or moving to applicationand assesses the difficulties inherent in theirtransition from research to commercial use. Theauthor then speculates upon future trends inaerospace structures and on the consequences foradvanced materials.

A theoretical study was undertaken to determine theeffect of taper ratio on the trailing vortexstructure of a high aspect ratio unswept wing. Thewing was modelled using lifting line theory, and thevortex was assumed to have a Rankine distribution ofcirculation. The results show that reducing thetaper ratio of the wing, decreases the maximumtangential velocity of the vortex as well as thevortex span while the core's diameter increases.Data is also presented showing the sensitivity ofinduced drag to wake vortex parameters.

ACT embodying FBW and digital computing is nowimplemented routinely in almost all classes ofaircraft, and is often essential in achievingperformance requirements. However, careful design,thorough understanding, and attention to detail arenecessary if the benefits of ACT are to be realisedand attention must be focused appropriately amongthe issues to be resolved to ensure that developmentproceeds efficiently and overall costs areminimised. This paper introduces structural couplingas one of the important “details” of FCS design, andshows how the “state-of-the-art” has developed atBAe Warton in order to help achieve the performancespecification for a modern weapons system, whilemaintaining a balanced and efficient FCS designeffort.