Wind-tunnel tests were carried out to evaluate the performance of the Computational Fluid Dynamics (CFD)-based air-intake duct shape optimisation of the European platform tiltrotor ERICA. A 1/2.5 scale model including the nacelle, the external portion of the wing and two interchangeable internal ducts reproducing the baseline and optimised shape were manufactered to be tested in the large wind tunnel of Politecnico di Milano. Moreover, tests were carried out with the model equipped with rotating blade stubs. The comprehensive experimental campaign included tests reproducing different forward flight conditions of the aircraft including cruise and conversion phases. The evaluation of the internal duct performance was carried out by measuring total pressure losses and flow distortion by directional probes at the Aerodynamic Interface Plane (AIP). Additional pressure measurements were carried out on the internal surface of the duct to compare the pressure distributions along the air-intake. The experimental results confirmed that the optimised duct offers significantly improved performance with respect to the baseline configuration not only in cruise, representing the flight condition considered for the CFD optimisation, but also for the conversion condition. In particular, a remarkable reduction of the total pressure drop at the AIP was found with the optimised duct with the only exception for the stubs-on configuration in cruise. Indeed, the present investigation highlighted that the design of the blade stubs, particularly their length, represents a very critical aspect for air-intake performance tests due to significant disturbances that could be induced by the stubs’ wake on the internal duct flow.

Measured characteristics of compressible constant pressure adiabatic turbulent boundary layers are correlated in an incompressible frame of reference with the aid of a modification of the well known Mager compressibility transformation. Quite good data collapse is obtained although the transformation is shown to be deficient in the outer regions of the boundary layer. The results will be used to produce data sheets of constant pressure adiabatic turbulent boundary layer properties.

The feasibility of using a single effective on-line control law to regulate the dynamic response of a jet engine throughout its flight envelope is of considerable importance. In this paper, a study was made to find such a single effective control law, which was able to regulate the dynamic responses of the linear, and ultimately the non-linear, model, throughout the engine’s entire operating range. This effective control law was obtained from solving a Linear Quadratic Problem (LQP) to obtain an optimal control law, a linear state feedback control.

Ladies and Gentlemen, tonight we pay homage to Frederick William Lanchester, Doctor of Laws, Fellow of the Royal Society who, having become interested in mechanical flight at the age of 21, while studying at South Kensington in 1889, entered the field of aeronautics in 1892 and continued to aid its development until his death in 1946. His great contributions to aeronautics were the discovery of the theory of the vortex motion of the lifting wing and that the key to successful flight lay in reducing the skin friction, which was far from being the negligible quantity that others such as Langley, whose name is forever remembered through NASA Langley Field, had stated earlier. All this was in 1893 to 1894 some ten years before the first flight of the Wright brothers. When asked later how he had successfully derived his great and momentous theory Lanchester simply stated; ‘it was a matter of logical deduction helped by experiment’. He vigorously defended his work as not being empirical but was soundly based on hydrodynamic theory.

Within recent years the subject of anodic oxidation has been very fully and minutely examined, notably by Bengough, Stuart, and Dr. Sutton, who was responsible for the large-scale experiments carried out at the Royal Aircraft establishment, Farnborough, and who, with his collaborators, has presented a number of excellent papers to the Royal Aeronautical Society, the Institute of Metals, and other bodies. In addition, scientists and industrialists at home and abroad are continuously adding to knowledge of aluminium, its uses and adaptability, and are giving a growing impetus to penetrations into spheres formerly exclusive to steel, brass, copper, tin and timber, each substitution calling for special consideration, so that it is well-nigh impossible for one to broach the subject without impinging somewhere upon the work ol others.

The Chairman, in opening the meeting, said that after all the comment in the Press in the last few days concerning the noise of helicopters flying over London and in view of the possibility of further comment in the immediate future because of the existence now of a heliport in London, it was opportune that the Association should be having a lecture this evening on “Helicopter Noise Suppression” from one of its members, Mr H B Irving, who was a leading authority on the subject

The statement that with modern aircraft and jet propulsion engines it is essential to match the engine and aircraft has become a platitude, without the reasons being quite so well appreciated. It is well known that should the aircraft be operating away from its “ design point,” involving throttling back of the engine, then the loss of efficiency with either jet or turbine airscrew engines is liable to be serious, and to have a large effect on the range. There is also a firm conviction that very high altitude is necessary in order to give a jet aircraft any range worth mentioning.

It seems worth while to examine in a simple way on what qualities of the engine the range depends. The object of this simplified attack on the problem is two-fold; first of all it enables the factors to be readily appreciated, and second it provides rapid methods of comparing the qualities of two different engine types for range.

Ward’s slender-body theory is extended to derive first approximations to the external forces on slender bodies of general cross section with discontinuous profile slope. Two classes of body are considered: bodies whose profile (typified by the local radius) is continuous between the nose and base, and certain bodies whose profile is discontinuous, such as bodies with annular or side air intakes and wing-bodies on which the wing has an unswept leading edge. (Where air intakes are concerned, it is assumed that they are sharp-edged and that there is no “ spillage ” of the internal flow).

The following conclusions apply to the former class of bodies. The variation of drag with Mach number is found to depend only on the discontinuities in the longitudinal rate of change of the cross-sectional area, and is thus independent of cross-sectional shape. The drag itself is unchanged if the direction of the flow is reversed. The expressions for lift and moment assume the same forms as for smooth pointed bodies, the lift depending only on conditions at the base of the body.

The general theory is applied to winged bodies of revolution with an unswept wing leading edge: the results bear a marked resemblance to those obtained by Ward. The results for wings alone are seen to be applicable, with one modification, to subsonic as well as to supersonic speeds.

An experimental investigation of cone cavity flow at M = 8·2 with injection of air and helium has been performed in the Cranfield University gun tunnel. The cone used had a 10° semi-angle and incorporated an annular cavity. The boundary layer ahead of the cavity was laminar. The study concentrated on the effects of increasing the mass injected into the cavity.

With no injection the external flow bridged the cavity. A shock wave and a pressure peak occurred at the rear face corner. By injecting gas, this pressure peak was decreased in intensity and a shock wave was formed at the front face corner. As the mass injected was increased, the shocks initially formed at the front and rear face corners were shifted upstream from their initial positions and boundary layer separation occurred ahead of the cavity. For the highest mass flow rate injected, the pressure peak at the rear face corner was very small. The cavity flow was never more than mildly unsteady.

Internet applications have been extended to various aspects of everyday life and offer services of high reliability and security at relatively low cost. This project presents the design of a reliable, safe and secure software system for real-time remote operation and monitoring of an aero gas turbine with utilisation of existing internet technology, whilst the gas turbine is installed in a remote test facility

This project introduces a capability that allows remote and flexible operation of an aero gas turbine throughout the whole operational envelope, as required by the user at low cost, by exploiting the available Internet technology. Remote operation of the gas turbine can be combined with other remote Internet applications to provide very powerful gas-turbine performance-simulation experimental platforms and real-time performance monitoring tools, whilst keeping the implementation cost at low levels.

The gas turbine used in this experiment is an AMT Netherlands Olympus micro gas turbine and a spiral model approach was applied for the software. The whole process was driven by risk mitigation.

The outcome is a fully functional software application that enables remote operation of the micro gas turbine whilst constantly monitors the performance of the engine according to basic gas turbine control theory. The application is very flexible, as it runs with no local installation requirements and includes provisions for expansion and collaboration with other online performance simulation and diagnostic tools.

The problem of the stress analysis of circular fuselage frames has been investigated by a number of authors; the analyses are, necessarily, rather mathematical in nature although in some cases the final results have been presented in extremely practical form. The present paper offers, in non-mathematical language, a short account of the fundamentals of the problem and a brief guide to the more important published literature. It also develops an approximate method for the analysis of frames using Lagrange's method for minimising a function of several inter-dependent variables. This method is shown to be particularly suitable for the analysis of frames with large cut-outs, about which little has previously been published. In addition, the underlying parameters which determine the stress distribution are deduced from the theory, and the deductions are compared with previously published work. In general, agreement is good. The paper is written throughout with a view to being of practical use in the actual stressing of frames. Numerical examples and explanations of mathematical methods are included in Appendices.

In a recent paper, Yates has shown that it is convenient to distinguish between two main types of stimulus which induce torsional vibration in geared-shaft systems. The first, which is dealt with in detail in the literature, is “force excitation” by which periodic torques act upon the system and throw it into oscillation; for the purpose of this note, it will be convenient to refer to a previous article as dealing with this problem.

The second type of excitation to which Yates refers is “displacement excitation.” It may be thought of as arising from errors in the cutting of gears which cause periodic variations in the velocity ratio of mating components. A Hooke's joint which couples two rotating systems which are capable of torsional oscillation would give rise to this form of stimulus.

The engine parameters which most obviously must improve to contribute to the continued lowering of aircraft Direct Operating Costs are those of prices, weight, volume and fuel consumption. These affect the base-line performance characteristics of the aircraft and in any formula for estimating Direct Operating Costs they will appear in the general cost of flying a load of passengers or freight from A to B.

A meeting of the Royal Aeronautical Society was held in the lecture hall of the Institution of Civil Engineers at Great George Street, Westminster, London, S.W.1, on Thursday 5th December 1946, at which a paper by Mr. J. K. Hardy on “ The Protection of Aircraft Against Ice,” was presented and discussed. In the Chair, the President, Sir Frederick Handley Page, C.B.E.

In this paper the emphasis is on safety problems connected with the use of light fixed-wing aircraft for agricultural purposes. Most of the aircraft concerned are between 2000 and 6000 lb all-up weight and are single piston-engined types. About 97 per cent of all hours flown in agricultural aviation all over the world are by such small fixed-wing aircraft, the remainder by larger aircraft such as the DC-3 and helicopters.

The mass of statistics available on this type of flying is therefore confined to the small fixed-wing aircraft and since this type is obviously the most important with respect to this activity, then it is appropriate to concentrate on this type.

As The strength of aluminium alloys is increased, other desirable properties are increasingly sacrificed and, as with other metallic materials, a major difficulty in developing better strong alloys is to assess these other properties in terms which are satisfactory indices of service performance. This difficulty becomes more acute as strength is increased and further progress demands that supplier and user are in the closest possible agreement on methods of assessing the properties involved and on where the line must be drawn between acceptable and unacceptable material behaviour. Discussion of this aspect of strong light alloy development is always opportune and much of what is said in this paper is intended to provoke constructive discussion between supplier and user on this subject.

The equations of motion of many mechanical systems reduce to ordinary differential equations with time dependent parameters. A single degree of freedom system, with the damping and restoring forces varying with time according to the law … m (t+k)nhas been studied using the WKBJ approximation. The general solution of the differential equation can be used to arrive at the response of such time dependent systems, subjected to excitations which are specified to be of either deterministic or stochastic nature.

The design of guided missile systems presents a wide spectrum of problems to engineers in numerous disciplines which range through aerodynamics, electronics and signal processing. Of all the tasks involved in the design process, perhaps the most difficult is the integration of the various technologies into a complete, harmonised system. IMPACT is a computer program which was developed to address the system design aspects of homing guidance missile systems. The aim of this paper is to describe the engineering philosophy and theoretical background to the IMPACT program.

Sir Henry Tizard’s work and–above all–his part in our survival in 1940–have been the subject of many memoirs since his death in 1959. The biography written by Ronald Clark at the invitation of Professor J. P. M. Tizard, Sir Henry’s eldest son, will shortly appear. This first Memorial Lecture of the Royal Aeronautical Society thus occurs when a full record of Tizard’s life is about to be made available, and there is therefore little point in the plain re-iteration of a condensed biography. Future Memorial Lecturers, as they inevitably grow more remote from personal contact with Tizard, may well choose to describe the advances of the future in those fields to which Tizard himself so notably contributed: science, defence, education and government. My purpose in this first Memorial Lecture is, therefore, to build a bridge between biography and those future fields in which Tizard’s example, although unlikely to be excelled, will be emulated and extended.