The authors predict that rocket engines will fall into two categories. In both, combustion pressures will approach 200 atmospheres to attain optimum vehicle performance, balancing increased pumping losses and engine mass against increased expansion efficiency and reduced dissociation. For general purposes, engines will be intrinsically convenient: storable propellants will give specific impulses around 270 lb. sec./lb., and engine specific weights will be between 0·02 and 0·03. For exacting applications, the greatest overall convenience may necessitate using unpleasant propellants so as to obtain the highest performance. Immediate research into the use and handling of these is essential if future engine development is not to be hampered.

The compressible subsonic flow about an oscillating two-dimensional aerofoil in a wind tunnel with porous walls is considered. The porous wall is assumed to exhibit the property that the ratio of the normal velocity at the wall to the pressure drop across the wall is constant. The aerodynamic derivatives are found for quasi-steady pitching motion of the aerofoil. The dependence of the derivatives on Mach number and wall porosity is displayed graphically.

A photoelastic layer was bonded to the face of aluminium alloy lugs and the strain distribution in the lugs was determined from the photoelastic fringe patterns which were recorded in a reflection-type polariscope. The semicircularly- ended lugs were loaded through neat fitting hardened steel pins. Assuming the maximum shear stress criterion of yield, the region of yielding under different loads was determined from the fringe patterns. Yield contours are shown for each of the four ratios of (hole diameter)/(lug width) tested. The greatest shear strains in the lugs were related to the applied loads. The extent of yield across the section normal to the direction of loading was measured for different loads and it was found that the progress of yield across this section is independent of the (hole diameter)/(lug width) ratio. The residual stresses on this section were also estimated. Complete yielding across the lug was related to the properties of the material and to the fracture strength of the lugs. Local yielding due to surface irregularities remained local, showing that “bedding in” does not weaken the component under static loading conditions.

On the basis of the linearised theory, the integral relationship for the incidence distribution in terms of the velocity potential is established for wings with subsonic leading edges. Some analytical problems are analysed. A simple general numerical method is given for this design problem which compares favourably with exact linear theories. In Part II, to be published, a further numerical method is developed, for calculating the loading on any specified thin wing with subsonic leading edges, which again agrees favourably with exact linear theory. Both of these numerical techniques can be easily accommodated on desk calculating machines.

Expressions are obtained for the radial and tangential bending moments in a circular plate under the combined action of (a) a lateral load concentrated on the circumference of a circle and an end tension or compression, and (b) a uniformly distributed lateral load, having a diameter less than the diameter of the plate, and an end tension or compression. For both types of loading, solutions are obtained for plates which are simply-supported and for plates with an arbitrary end rotation.

In addition, the following limiting cases are considered: (i) concentrated lateral load with end tension or compression, and (ii) an infinite plate under the simultaneous action of an end tension and a lateral load concentrated on the circumference of a circle of finite diameter.

A slender ducted body of arbitrary cross section is studied. This possesses an annular, side or “scoop” type of intake at some streamwise station. The parts of the body forward of and behind the intake are both permitted to have discontinuities of longitudinal profile slope at streamwise stations widely separated both from each other and from the intake. The external flow is taken to be entirely supersonic and it is assumed that the intake lip is sharp and that there is no “spill over” due to choking of the internal flow, which must be supersonic for a short distance inside the duct.