Inertial navigation is a completely new approach to the navigational problem initiated to a very large extent by the military requirement for a blind navigational system which could not be jammed by, nor give actual assistance to, any potential enemy. It relies for its operation on principles which were understood by Newton, but the practical realisation of a working system has become possible only by the intensive development in both the design and manufacturing techniques of gyroscopes and accelerometers. This development work has, to a considerable extent, been stimulated by Dr. Draper of the Massachusetts Institute of Technology and, although he may not be the inventor of inertial navigation as such, there is little doubt that but for the work carried out under his direction, inertial navigation would still be little more than a dream.

Inertial navigation depends basically on the simple fact that if we can measure the acceleration vector of a body in any convenient axis system, then by carrying out the suitable integration processes we can determine its path in space, its position and its distance from its initial position.

The circular cross-sectional Royal Aerospace Establishment (RAE) 2129 S-shaped intake diffusing duct series, shown in Fig. 1, which has an offset of the inlet and exit centerline of 0·3 and 0·45 of the axial length of the duct, was designed at the RAE (Bedford) and tested at British Aerospace Filton, at low forward speeds (freestream Mach no. range from 0 – 0·2 but a range of duct inlet Mach numbers up to choking speeds) in the last two decades to fulfil the objectives of collecting systematic experimental data on engine face pressure recovery, total pressure flow distortion and wall static pressures for computational fluid dynamics validation. Some of the measurements have been presented, as for example, by Willmer, Brown & Goldsmith. The measurements from one version of Model 2129 (the 0·3 length offset S-duct geometry) have been used to compare with calculated results from a number of CFD programs, as for example, by Anderson, Horton and by the AGARD Working Group 13. The series of comparison also highlight the need for measurements other than the engine face total pressure and wall static pressure which have already been made.

Wing Commander BRIE said that Mr BRISTOW had been connected with many aspects of helicopter development for a number of years He first learned to fly helicopters in 1944 at Floyd Bennett Field, U S A, and in 1946 was a helicopter test pilot with Westland Aircraft Ltd In 1948 he received the Royal Aero Club Silver Medal for the relief of the Wolf Rock Lighthouse, and in 1949 the Croix de Guerre for jungle rescue in Indo China whilst he was Technical Manager and Chief Pilot with Hehcop-Air, Pans In 1950 he formed his own company, Air Whaling Ltd and pioneered the use of the helicopter for whaling m the Antarctic In 1955 he formed Bnstow Helicopters Ltd , and tonight we are to hear an account of the work being done by this Company in the Persian Gulf and the large part the helicopter plays in transporting men and materials from the mainland to the drilling rig fifty miles out in the Gulf

For centuries, scientists and engineers dreamed of going to the moon or the planets, but the more they learned about the problems involved, the more improbable space flight appeared.

While there were many difficult questions, the principal problem overshadowing all others was how to propel the vehicle free of the earth's gravitation.

When serious attention finally was devoted to the magnitude of the thrust required and the means for obtaining it, space flight became a real possibility. This assurance of adequate propulsion marked the true beginning of the space age, and continues to be the prerequisite for the more ambitious space flights planned for the future.

This paper deals with the study of the power matching of the propulsion system and on-board systems changing the on-board systems’ electrification level. In particular, four system architectures have been studied, each one with a different level of electrification starting from the More Electric Aircraft (MEA) to the All Electric Aircraft (AEA) systems. The mass and the power requirement of each system architectures have been analysed together with the change in engine specific fuel consumption. Then, these results have been used to quantify the influences of engine and systems power matching to the entire aircraft. In particular, the beneficial effect of system electrification has been evaluated as an increment of aircraft range. Moreover, two reference aircraft – a regional jet and a short/medium range liner – have been selected to understand the variance of the power matching changing aircraft dimensions and mission range. The study is carried out using a distributed and collaborative Multi-Disciplinary Design Analysis and Optimization (MDAO) environment. The results show a beneficial effect of systems electrification on systems mass and engine specific fuel consumption. At aircraft level, the results point out an increment of aircraft range up to 7.7% with a different trend for the two studied cases.

The momentum equation is used to calculate the drag that acts near the tip of a semi-infinite swept-forward wing of constant chord that is at zero incidence to a uniform stream of incompressible, inviscid fluid. The drag is given as a function of wing section and angle of sweep and is shown to be unaffected by shaping the tip. The results may be used to calculate the drag that acts near die centre and the thrusts that act near the tips of a swept-back wing, provided that its aspect ratio is sufficiently great for the regions where the different forces act to be separated. Some results due to Neumark and to Küchemann and Weber suggest that this will be so provided that the aspect ratio is greater than about two. The results are combined with some due to these authors to estimate the spanwise extent of the forces. It is found that this extent decreases as the angle of sweep is increased and that it depends quite markedly on the wing section.

The mathematical model of aerodynamic forces and moments is described, based on results from various wind-tunnel experiments with the RAE High Incidence Research Model (HIRM). Simulations of the responses due to longitudinal and lateral control inputs at high angles of attack are compared with the responses measured on free-flight models of the configuration. It is shown that the main features of the flight behaviour are reproduced, in particular such phenomena as roll-off, wing rock and nose slice.

Loads have been measured on wedges placed symmetrically in supersonic jets of air. The jets were created by a nozzle with a radially divergent exit section having a lip Mach number of 2.2. The underexpansion ratio was varied from 1 to 2.2 and the distance between the nozzle exit section and the wedge apex was varied from 0 to 2 nozzle exit diameters. All wedges had a base width equal to the nozzle exit diameter: their total included apex angles covered the range 30° to 180°. Pressures were measured on the front faces and the bases for three of the wedges, hence enabling individual contributions to the overall force to be evaluated. Overall loads were measured by means of strain-gauged supports for all six wedges. It was found that the overall load coefficient is only weakly dependent on underexpansion ratio and wedge location but depends strongly on wedge angle. The maximum load coefficient recorded corresponded to 73% of the jet momentum. The base pressures contribute up to 59% of the overall load on a 45° wedge but rather less for larger wedge angles.

In an effort to quantify the feasibility of candidate space architectures for astronauts servicing Geosynchronous Earth Orbit (GEO) satellites, a conceptual assessment of architecture-concept and operations-technology combinations has been performed. The focus has been the development of a system with the capability to transfer payload to and from geostationary orbit. Two primary concepts of operations have been selected: (a) Direct insertion/re-entry (Concept of Operations 1 – CONOP 1); (b) Launch to low-earth orbit at Kennedy Space Center inclination angle with an orbital transfer to/from geostationary orbit (Concept of Operations 2 – CONOP 2). The study concludes that a capsule and de-orbit propulsion module system sized for the geostationary satellite servicing mission is feasible for a direct insertion/re-entry concept of operation CONOP 1. Vehicles sized for CONOP 2 show overall total mass savings when utilising the aero-assisted orbital transfer vehicle de-orbit propulsion module options compared to the pure propulsive baseline cases. Overall, the consideration of technical, operational and cost factors determine if either the aero-assisted orbital transfer vehicle concepts or the re-usable/expendable ascent/de-orbit propulsion modules is the preferred option.

Many complex machines and mechanical systems have an ideal and abstract form which has been evolved from fundamental theory without reference to those engineering principles that are so essential in practice. Thus the heat engine has its Carnot cycle and the propeller its actuator disc. With these, and numerous other examples, the object is to provide a standard of reference, to give an ideal which can be approached but never reached and, most important, to indicate the fundamental limitations imposed by theory and prevent profitless investigations.

In using the method of stage stacking to compute the off-design performance of multi-stage axial compressors, it has been observed that the limitation on performance at speeds above the design speed has been set by the stall and the choke points of the rear stages(1). Thus if the rear stages can absorb a wide range of mass flows between stalled conditions and choked conditions, a better performance could be obtained.

Compressor stages using low stagger blades will absorb a large range of mass flow between stalled and choked condition; but because of the high axial velocity involved in their use, they tend to be unsuitable for low pressure stages because of the high Mach number obtained. In the higher pressure stages the increased gas temperature will lower the Mach number for the same velocity and give more efficient operation.

The design of structures for operation at increasingly higher temperatures and under exposure to severe heating requires more detailed and more exact analysis to determine the most severe conditions under which a given structure is operationally effective. To meet this need, the following analysis has been devised, with the determination of stresses and deflections in plates due to non-uniform heating as its purpose. The analysis results also in the determination of the maximum loads which may be imposed on the supporting members by the plate due to its thermal deformations.

Experimental results are presented of the measurement of the ratio of the wall shear stresses at the inner and outer surfaces of concentric annuli. Five radius ratios were investigated with Reynolds numbers in the range 2000-89 000 with air. The Reynolds number is defined as where ū is the bulk velocity.

It is concluded that the ratio of the shear stresses is very different from the corresponding laminar flow value and is a function of both radius ratio and Reynolds number.

The design of the damped tuned vibration absorber, which has previously been treated algebraically, is studied by the use of a three-dimensional admittance diagram. The advantages of this method are that the basic principles can be more easily understood and that it is not necessary to simplify the vibrating system so much. The results obtained by the use of the method show that under some conditions the algebraic treatment does not give the optimum tuning, but that the differences in performance of dampers which have been designed by the two methods will not be large. It is shown how the method may be extended to more complex problems.

The paper presents a method for the prediction of mean flow data (i.e. skin friction, velocity profile and shape parameter) for adiabatic two-dimensional compressible turbulent boundary layers at zero pressure gradient. The transformed law of the wall, law of the wake, the van Driest model for the complete inner region and a correlation between the Reynolds number based on the boundary layer integral length scale (ReΔ*.) and the Reynolds number based on the boundary layer momentum thickness (Reθw) were used to predict the mean flow quantities. The results for skin friction coefficient show good agreement with a number of existing theories including the van Driest II and the Huang et al. Comparison with a large number of experimental data suggests that at least for transonic and supersonic flows, the velocity profile as described by van Driest and Coles is Reynolds number dependent and should not be presumed universal. Extra information or perhaps a better physical approach to the formulation of the mean structure of compressible turbulent boundary layers even in zero pressure gradient and adiabatic condition, is required in order to achieve complete (physical and mathematical) convergence when it is applied in any prediction methods.