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Aircraft Engineering and Aerospace Technology, vol. 75 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 October 1953

J. Lukasiewicz

Ideal and practical performance of ram‐jet units in steady flight in the stratosphere at Mach numbers from 1·5 to 4 is examined. The effects of combustion, temperature, altitude…

Abstract

Ideal and practical performance of ram‐jet units in steady flight in the stratosphere at Mach numbers from 1·5 to 4 is examined. The effects of combustion, temperature, altitude, intake and exhaust nozzle design are considered.

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Aircraft Engineering and Aerospace Technology, vol. 25 no. 10
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 November 1961

J.G. Keenan

Because of its high overall pressure ratio and good propulsive efficiency, the jet engine is very efficient for supersonic propulsion. A high thrust per unit power plant frontal…

Abstract

Because of its high overall pressure ratio and good propulsive efficiency, the jet engine is very efficient for supersonic propulsion. A high thrust per unit power plant frontal area and per unit weight are primary requirements and these imply high combustion temperatures. For a Mach 2.0 aircraft, engine design problems other than this are not outside existing experience but additional problems, such as bearing cooling, become more serious at cruise Mach Numbers approaching 3.0. A variable intake is essential and the method of geometry variation and control requirements are described. Variable propulsion nozzle design is also an area of vital importance and it is not claimed that an entirely satisfactory solution, giving good performance with low drag in the transonic phase, has yet been achieved. The ‘sonic boom’ phenomenon can have an important influence on engine design, in that it may determine the maximum altitude at which the aircraft has to fly subsonically. Should this be appreciably above the tropopause, then it will not only influence the amount of thrust installed but may also dictate the fitment of reheat for the transonic acceleration. Take‐off noise is a requirement which can influence both the installed thrust and the choice of engine type. Despite the lack of firm standards for field noise and ‘coast‐over’ noise, there is good reason to believe that the noise levels of a supersonic transport need not exceed those of the quieter long‐range subsonic transports in service at this time.

Details

Aircraft Engineering and Aerospace Technology, vol. 33 no. 11
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 December 1978

P.J. WHEELER and N.J. ESSEX

Concorde AIDS data is used by British Airways for Performance Trend Monitoring, engine control law verification and Low Cycle Fatigue life usage sampling. This paper outlines the…

Abstract

Concorde AIDS data is used by British Airways for Performance Trend Monitoring, engine control law verification and Low Cycle Fatigue life usage sampling. This paper outlines the requirements for these monitors with reference to the special needs of the Concorde powerplant, together with the content of the Rolls‐Royce computer programmes. The British Airways data acquisition, extraction and verification systems are also covered, together with the use of outputs within the airline organisation.

Details

Aircraft Engineering and Aerospace Technology, vol. 50 no. 12
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 29 June 2012

Alberto Boretti

The paper focuses on the conversion of a Diesel engine to CNG, with emphasis on the use within Australia where the refueling network is scarce, and the developments needed in the…

Abstract

The paper focuses on the conversion of a Diesel engine to CNG, with emphasis on the use within Australia where the refueling network is scarce, and the developments needed in the injection and combustion systems to further improve the fuel conversion efficiency and reduce the in-cylinder pollutant formation. For dual fuel CNG-Diesel operation, the best option is the adoption of two independent fuel injectors for the Diesel and the CNG, while for the single fuel CNG operation, the best option is the adoption of one direct CNG injector plus a jet ignition device accommodating a second CNG injector and a glow plug. With both designs, the CNG engine would operate following different modes of combustion, not only the traditional Diesel like, but also the traditional gasoline-like, a mixed gasoline/Diesel-like and finally HCCI-like depending on the injection strategy adopted for the two injectors of each cylinder. Computations of gas exchange, heat release and heat transfer processes are computed with an engineering performance simulation code with the model for the Diesel fuel validated versus extensive experimental data.

Details

World Journal of Engineering, vol. 9 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 August 1958

The background of missile costs is discussed. Missiles are new and very costly. Developments in this field have been subjected to political vicissitudes which have often upset…

Abstract

The background of missile costs is discussed. Missiles are new and very costly. Developments in this field have been subjected to political vicissitudes which have often upset long‐term developments. Missile technology is on the frontier of science and there is no background of knowledge to draw on; much basic and expensive research is required. Missile engineering models are complex in detail and assembly, and therefore costly, and constant change occurs while making and testing the model. The complexity and functional requirements of missile parts are running a parallel race with the machines and processes being developed to fabricate the materials required. The usually small runs required in missile production again add to costs. Imposed on all these activities is the requirement that reliability of near 100 per cent is needed and in no case can reliability be allowed to be secondary to cost. The inflight life and shelf conditions for a missile are usually fairly well established and 100 per cent reliability for a short operating life with a long shelf life are the real requirements. There is a considerable tendency to overdesign for reliability. Some costly features of design such as finest finish, closest tolerances and highest strength are carried over by habit from aircraft design and are not always required in missiles. Having examined some causes of high costs, a programme for cost reduction is set out. Costs can be reduced by: (i) earlier freezing of designs making changes only in groups of several changes at wider intervals, (ii) making a more realistic approach to reliability designs, (iii) selecting tolerances in a more analytical manner according to individual needs, (iv) selecting materials on the basis of actual design requirements instead of using the very best materials available even when the short life makes them unnecessary, (v) avoiding tool‐room methods in production engineering, (vi) setting work standards on as many operations as possible and enforcing them to the greatest degree possible, (vii) selecting the best type of workers to make the transition from development models to production missiles as smooth as possible, and (viii) setting up rigid systems and parts designation procedures for handling production parts. Finally, methods of organizing research and development and production for bridging the gap between engineering design and production are proposed.

Details

Aircraft Engineering and Aerospace Technology, vol. 30 no. 8
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 January 1948

THE Rainbow is the commercial adaptation of the XF‐12 photographic aeroplane the Republic Aviation Corporation completed for the Army Air Forces. In 1943, the Photographic Section…

Abstract

THE Rainbow is the commercial adaptation of the XF‐12 photographic aeroplane the Republic Aviation Corporation completed for the Army Air Forces. In 1943, the Photographic Section of the A.A.F. issued specifications for a new multi‐engined, long‐range, high‐speed, reconnaissance aeroplane to fly at very high altitudes. The required performance was so much beyond anything in existence at the time that it posed a real problem to designers of high performance aeroplanes. Republic engineers, who for years had specialized in high‐altitude, high‐speed pursuit planes, eagerly accepted the challenge. After exhaustive studies it was found that the performance required by the specification could only be met with a four‐engined machine using Pratt and Whitney R‐4360 engines, supercharged to carry full military power to 40,000 ft. Other combinations would either fail in speed, or in range, or in desired rate of climb or ceiling. A proposal based on four 4360 engines was submitted to the A.A.F., and in March 1944, the Company was awarded a contract for two XF‐12 aircraft. The first prototype was completed in December, 1945, and made its first flight on February 4, 1946.

Details

Aircraft Engineering and Aerospace Technology, vol. 20 no. 1
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 August 1998

Jaroslav Mackerle

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder…

4528

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

Details

Engineering Computations, vol. 15 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 21 September 2010

Chun‐Hsiang Yang, Di‐Han Wu and Chiun‐Hsun Chen

Utilizing renewable energy and developing new energy sources are practical responses to the shortage of fossil fuels and environmental regulations for carbon dioxide emissions…

Abstract

Purpose

Utilizing renewable energy and developing new energy sources are practical responses to the shortage of fossil fuels and environmental regulations for carbon dioxide emissions. The purpose of this paper is to assess the practicability of using low heating value (LHV) fuel on an annular miniature gas turbine (MGT) via numerical simulations.

Design/methodology/approach

The MGT used in this study is MW‐44 Mark I, whose original fuel is liquid (Jet A1). Its fuel supply system is re‐designed to use biogas fuel with LHV. The simulations, aided by the commercial code CFD‐ACE+, were carried out to investigate the cooling effect in a perforated combustion chamber and combustion behavior in an annular MGT when using LHV gas. In this study, four parameters of rotational speeds are considered. At each specific speed, various mixture ratios of methane (CH4) to carbon dioxide (CO2) including 90, 80, 70, and 60 percent were taken into consideration as simulated LHV fuels.

Findings

The simulation results show the chamber design can create a proper recirculation zone to concentrate the flame at the center of the chamber, and prevent the flame from expanding to cause hot spot. Furthermore, the hot gas exhausted from combustor outlet is cooled down effectively by jet flow discharged from dilution holes, which prevent turbine blade from heat damage.

Originality/value

Simulation results demonstrate that CFD‐ACE+ can simulate flow field performance and combustion behavior in an annular MGT precisely. The results of these CFD analyses confirm that the methane fuel can be used in such small volume of MGT and still have high performance. With the aid of the constructed combustor model, the performance of a methane‐used MGT can be realized before the experiment procedure starts.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 20 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 May 1949

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Notes of the United States National…

Abstract

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Notes of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

Details

Aircraft Engineering and Aerospace Technology, vol. 21 no. 5
Type: Research Article
ISSN: 0002-2667

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