A large deflection theory is established for the bending and stretching of aeolotropic plates with elastic moduli that vary in the x, y, z directions. The theory is formulated in terms of two simultaneous non-linear differential equations, with variable coefficients, for the transverse deflection w and an Airy stress function F. Small deflection heterogeneous plate theory and some other sub-classes of plate problems are formulated by specialising the general non-linear plate equations. Effects of initial irregularities and of a variable elastic foundation are considered.

The concept of an idealised “unique” stage characteristic is employed to analyse and understand the performance of axial compressors. It is shown that there exists a “matching” line across the compressor characteristics at any point of which all the stages are operating at the same point of their “unique” stage characteristic, and that this matching line is readily obtainable, almost from inspection. Simple calculations lead to a derivation of both this “unique” characteristic and the effective area ratio of the compressor. The behaviour of the stages at other points than the matching line is readily understandable and presents a simpler picture of compressor performance than is often obtainable from actually measured stage characteristics.

The elastic stress concentration factors for the torsion of solid and hollow shouldered shafts have been determined by means of a pure resistance electrical analogue. Fillet radii ranged from 0.05 to 1.0 times the diameter of the smaller shaft, and the shoulder diameter increased from 1.0 to 8.10 times the diameter of the smaller shaft. A comparison is made with the results of other techniques. A study has also been made of the formation of a plastic region in the neighbourhood of the fillet.

The paper presents the results of an experimental study of the buckling of transversely stiffened shear webs when the stiffeners have a thickness less than that of the web-plate.

It is shown that the effectiveness of such stiffeners is greatly influenced by two factors, the ratio of the thickness of the attached leg to that of the web-plate and the position of the connecting rivet. An empirical design rule relating these two factors is presented.

The possibility of obtaining two-dimensional turbulent jet flow from a series of closely-spaced uniform holes in line has been investigated both theoretically and experimentally. The case studied was that of a jet discharging into still fluid of similar density at incompressible speeds. Such a quasi-two-dimensional jet is a particular example of a multiple-interfering jet group.

This paper covers an investigation into a new way of assisting the pilot to hover an unstabilised jet-lift aircraft. In a normal control system the aircraft is controlled by a moment which varies linearly with stick position. In this paper control systems were considered in which the controlling moment was a linear function of the position and rate of change of position of the stick. The investigation was primarily limited to optimising such a system with freedom restricted to rolling motion and the associated lateral displacement. Effects of limited control power and engine failure were considered. With the optimum control the mean errors in position recorded when hovering were under half those achieved with a normal manual control and the results were almost as good as for an ideal rate-stabilised aircraft. Extending the investigation to both pitch and roll planes led to an even greater improvement, even when the effects of gyroscopic coupling between the two planes were taken into account. The precise engineering of a “mixed” control system of the type discussed needs much thought and it will require considerable development, but the results achieved indicate that it may prove an attractive alternative to an autostabiliser

The paper presents a solution for the buckling under shear of a rectangular plate which is clamped along one edge and simply-supported along the other edges. The authors have also re-examined the case of one pair of opposite edges clamped and the other pair simply-supported.

A study has been made of the effects of inlet coolant injection upon axial compressor performance, using the results of tests on turboshaft engines. It is shown that evaporation of the coolant changes the stage work distribution as well as the ideal compression work and that these effects may be estimated by elementary thermodynamic methods. Simplified prediction procedures are suggested and compared with experimental results.

A solution is presented for the stresses in a half plane compactly reinforced along its straight edge and pierced by a reinforced circular hole in the vicinity of the edge. Numerical results are given for two cases of uniform applied tractions at infinity. In the special case of both boundaries unreinforced, the results obtained are in agreement with an existing solution by Mindlin.

The concept of the manoeuvre margin is discussed, and definitions are suggested which are applicable to all types of configurations. Calculations are presented for the manoeuvre characteristics of simplified flexible models representing conventional and slender integrated aircraft. Linear aerodynamics only are assumed.

A method of deriving a dynamic stiffness matrix for any non-uniform beam is presented. In particular, the case of a linearly tapered cantilever beam is considered, and excellent results are found with the use of only a few elements.

The complete analytical solution is presented to a problem formulated in an earlier issue of this publication.

The vorticity shed behind a finite wing has been studied and a condition found for steady circulation. This condition is then combined with three-dimensional boundary layer theory to find the lift of a finite wing. An example shows that on a thin ellipsoid of aspect ratio 6·37 the lift as found by the present method is 2 per cent lower than the lift obtained using a sectional boundary layer approach.

An investigation of the effect of a root gap is extended to the oscillatory pitching motion of a slender wing. Potential theory is used and the unsteady forces are shown to be reduced by the gap as drastically as the steady. These results cast doubt on measurements made by the technique of half-model testing. Viscous flow in the gap is discussed with reference to the possible types of model mount. The effect of viscosity may be to reduce the gap loss, but the extent of the improvement is uncertain.

An investigation has been made into the errors involved in using certain lumped parameter methods for the solution of beam frequencies. It is found that existing methods are not consistent for all boundary conditions. A new dynamic stiffness matrix has been formulated, which gives consistently good results for even a few elements. The error in the solution is always inversely proportional to the fourth power of the number of elements used.