Recent advances in aeronautical technology arereviewed, with particular reference to work in theUnited Kingdom, and the process is outlined wherebythese have progressed from fundamental researchthrough to exploitation in marketable products.Aerodynamic, materials, propulsion and avionicaspects are discussed and successful applicationsdescribed in commercial and combat aircraft andhelicopters. Current and anticipated advances intechnology are considered in the context of possiblefuture applications, including brief considerationof the possibility of a new generation of supersonictransport aircraft. Lessons are drawn from pastexperience on actions necessary now if theseadvances are to be exploited successfully inimproving the performance, or reducing theacquisition or operating cost, of the nextgeneration of aircraft, without introducing anunacceptable level of risk.

The results of a blade-vortex interaction (BVI) studyincorporating particle image velocimetry (PIV) arepresented. Test cases encompass a variety ofintersection geometries, including head-on parallelinteractions. Results provide quantified flowvisualisation images of the flows generated near theblade tip and inboard during interactions. PIVresults are examined in the light of understandinggained from previous pressure measurements made fromthe same BVI facility. Both the difficulties and theadvantages of utilising the PIV technique in thisapplication are discussed.

Effective control of combat aircraft at high angles ofattack requires the flight control system to operateto higher frequencies and gains. This increases thepossibility of excitation of the structural modes byaltering the aeroservoelastic stability of thecomplete system. This paper details the results oftests carried out on a rigid, 55° leading edge sweepdelta wing, half model fitted with a half spanelevon operated through a closed loop controlsystem. The effects of steady elevon deflections upto 40° angle of attack are described. The unsteadypressures resulting from elevon oscillations atfrequency parameters up to a value equivalent to thefirst wing bending mode of a typical combat aircrafthave been measured. The effect of the elevonoscillation on the elevon itself and on the bendingmode have been estimated by calculating the unsteadyhinge and root bending moments about the wing root.The lower surface, unsteady elevon effects werefound to be independent of incidence and frequencyparameter. The amplitude of response of the weakvortex on the upper surface of the wing reducedrapidly with frequency parameter. Above an incidenceof 10°, the vortex breakdown was above the wing andled to a further reduction in the vortex response.The vortex response lagged the elevon motion.

A number of modern “aerodynamic” bicycle wheels weretested at full scale speeds in a windtunnel. Theeffects of wheel geometry, rotational speed andcross winds on drag force, side force and yawingmoment were investigated.

Compared with a conventional spoked wheel, all the“aerodynamic” wheels were found to give similarimprovements in drag of approximately 25%. In crosswind conditions, aerodynamic characteristics werestrongly dependent on wheel geometry, butessentially independent of wheel rotationalspeed.