Experimental and analytical techniques are presented for the determination of the response characteristics of a scale-model aircraft wheel to changes in runway friction. Results obtained from tests using these techniques are given. The wheel spin-up acceleration is shown to be proportional to wheel load and to the magnitude of the surface friction coefficient after surface change. It is also found to be inversely proportional to brake torque, but is largely independent of speed. An increase of speed is shown to increase the distance required for spin-up of a locked wheel as it encounters surfaces of higher friction coefficient. Good correlation of these trends is obtained analytically.

The effects of tyre flexibility are indicated by the results of both the experimental tests and the analytical simulations. These effects may degrade the performance of aircraft antiskid braking systems. It is recommended, therefore, that simulations used in the development of such systems take proper account of tyre flexibility when modelling the dynamics of the wheel and tyre.

An investigation of the generic vibration of prestressed thick orthotropic cylindrical shells was carried out. A set of Flügge type equations. of motion for orthotropic shells has been reduced to an equivalent set of equations containing only non-dimensionalised geometrical parameters, loadings and generalised global constants of orthotropic materials. The influence and importance of the global constants on the vibration of cylindrical shells are studied. Based on the results, the figures shown in this paper are applicable for a large group of materials, making the understanding of the correlation between composite material properties and vibrational behaviour of the shells very easy. The results of this paper show that an increase in vibrating frequency is brought about by (1) increasing generalised rigidity ratio, (2) increasing transverse shear modular ratios, (3) decreasing generalised Poisson's ratio and (4) decreasing principal rigidity ratio. The key parameters to the problems are generalised rigidity ratio and principal rigidity ratio only.

Experiments were conducted to study the types of flow that occur on the lee surface of delta wings at supersonic speeds. Two sets of flat topped delta wings of different thickness (wedges with 10° and 25° normal angle respectively), each with leading edge sweep angles of 45°, 50°, 60° and 70°, were tested. The measurements, carried out at Mach numbers of 1·4, 1·6, 1·8, 2·0, 2·5 and 3·0, included oil flow visualisations (on both sets of wings) and static pressure distributions (on the thicker wing only). In addition, a 60° sweptback delta wing with a normal angle of 40° was also tested. The tests on this wing included both oil flow visualisations and static pressure measurements. From these and other existing measurements, the leeside flows have been classified into nine distinct types, namely (i) leading edge separated flow with secondary separation, (ii) leading edge separated flow with secondary and tertiary separation, (iii) leading edge separated flow with a shock wave beneath the primary vortex, (iv) leading edge separated flow with shock-induced secondary separation, (v) fully attached flow, (vi) flow attached at the leading edge with inboard shock-induced separation, (vii) mixed type of flow, (viii) flow with a leading edge separation bubble and (ix) leading edge separated flow with a shock wave lying on the lee surface in between the leading edge vortices. These types of flow have been displayed in a plane of Mach number and angle of attack normal to the leading edge. The experimental results indicate that increasing wing thickness has no qualitative effect on the types of flow observed but does shift the boundaries between some of the types of flow.