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The purpose of this paper is to analyze the effects of the PRD geometric parameters, including the area and aspect ratio, on the discharge and force characteristics of pressure relief process under various plenum compartment pressures and Mach numbers.

Under various plenum compartment pressures and Mach numbers, the effect of the area and aspect ratio on the discharge and force characteristics of the PRD are numerically investigated via a three-dimensional steady Reynolds-averaged Navier–Stokes equations solver based on structured grid technology.

When the aspect ratio remains constant, the discharge coefficient C_D, thrust coefficient C_T and moment coefficient C_M are not affected by the PRD. When the area is constant, the aspect ratio dramatically impacts the discharge and force characteristics because the aspect ratio increases, the discharge coefficient C_D of the PRD decreases, and the thrust coefficient C_T and the moment coefficient C_M both increase. When the aspect ratio is 2, the discharge coefficient C_D decreases by 14.7 per cent, the thrust coefficient C_T increases by 10-15 per cent, and the moment coefficient C_M increases by 10-23 per cent compared with when the aspect ratio is 1.

This study provides detailed data and conclusions for nacelle PRD researchers and actual engineering applications.

On the basis of considering the influence of operating conditions on the discharge and force characteristics of the nacelle PRD, the impact of geometric parameters, including the area and aspect ratio on the discharge and force characteristics is comprehensively considered.

Smiths Industries is to supply the head‐up display system for the Sea Harrier. The company will design, develop and make the electronic head‐up display and weapon aiming computer system for the latest version of the HS Harrier which will operate from Royal Navy ships.

FOR a number of years now it has been evident that a successor to the well‐tried Vickers Viscount and Convoir 240/340/440 series was required. However, the big problem was to design an aircraft such that its economics and passengerappealweresub‐stantially better than the machines it would ultimately replace. Other important factors which had to be con‐sidered were improved reliability, easier and cheaper maintenance, higher standards of safety and means of reducing ramp times. Furthermore, the difficult choice of passenger capacity and cruising speed had to be made. Probably the easiest decision was to employ the twin‐engine configuration with the power plants placed in the now familiar rear position, one on cither side of the fuselage.

The Equal Pay Act 1970 (which came into operation on 29 December 1975) provides for an “equality clause” to be written into all contracts of employment. S.1(2) (a) of the 1970 Act (which has been amended by the Sex Discrimination Act 1975) provides:

This paper aims to study and assess a new approach for prediction of changes of pressure during gas discharge inside the room protected by fixed gaseous extinguishing system by computational fluid dynamics (CFD) simulations.

The research program consisted of two stages. The first stage was dedicated to the experimental measurements of pressure changes during extinguishing gas discharge into the test chamber in a real scale (70 m³), for two relief openings that differ in their area. The next step was about performing CFD simulations forecasting pressure changes during gas discharge into the numerically represented test chamber. Estimation of the correctness and usefulness of the CFD model was based on a comparison of the CFD results with standard calculations and experimental measurements.

Numerical modelling of pressure changes during the carbon dioxide discharge was very close to the experiment. The obtained results had sufficient accuracy (in most cases relative error <15%), while the standard approach predicted pressure changes with an average relative error over 36% and did not estimate the decrease of pressure at all.

Conducted research confirms the viability of the new approach in modelling the pressure changes and indicates additional benefits of the numerical analyses in the determination of the fire safety of protected premises.

THE Trident IE fuel system, designed to operate on cither kerosene or JP.4, has a straightforward layout with few controls. Five integral tanks (FIG. 1), comprising four in the wings and one in the centre section, give a total of 5,880 Imp. gall, of which 2,000 Imp. gall, are contained in the centre tank. (Total fuel capacity of the Trident 1C is 4,960 Imp. gall, with 1,160 Imp. gall, in the centre tank.) Each wing inner tank has slightly more than twice the capacity of the outer.

FUEL SYSTEM GENERALTHE standard version or the F.28 has a conventional two‐tank fuel system with an integral tank in each outer wing section contained by the wing torsion box with a total capacity of 2,170 Imp. gal. or 17,200 lb. of fuel. The centre wing torsion‐box pro‐vides space for additional bladder type tanks with a capacity varying from 312 to 700 Imp. gal. or 2,460 to 5,500 lb. as desired.

Two interesting papers on crakcase explosions in diesel engines were presented at the recent Oil and Gas Power Conference, of the American Society of Mechanical Engineers at Dallas, Texas. In the first paper “Diesel Engine Crankcase Explosion Investigation”, given by G. W. Ferguson of the Texas Company, the author drew attention to the conflicting opinions as to the composition and state of the crankcase atmosphere in a normally operated Diesel engine and the mechanism of ignition and subsequent propagation of flame throughout the crankcase atmosphere.

Brief Details of Some of the Components and Equipment Produced by a Number of Companies in Support of the Hawker Siddeley Argosy Programme. EARLIER articles have dealt at length with the evolution, basic design philosopfhy and development, structural design and testing, aerodynamic design and performance, crew compartment and aircraft systems, as well as maintenance of the Argosy. It is the object of this final article to provide some additional information of a back‐up nature concerning the products supplied by specific firms for the Hawker Siddeley Argosy programme.