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Solutions of the twin plane jets HF chemical laser flow based on a turbulent kinetic theory, due to a modified Green’s function method, are presented. The calculated results of probability density function (PDF) of various chemical species in velocity space, and mass fraction concentration distributions of various reactants and products in the flow field, are revealed and discussed in this analysis. The transport phenomena of different pumping rate, collisional deactivation rate, and radiative deactivation rate in the interaction between the twin plane jets HF chemical laser show that the properties of species mass fraction concentrations, collisional reaction rate, and radiative incident intensity are the dominant factors. The present study provides the fundamentals for theoretical understanding of twin plane jets HF chemical laser and further application to multiple‐jet HF chemical laser analysis.

A turbulent kinetic theory due to Chung and a Green’s function method by Hong were employed to solve a reacting turbulent plane jet problem. An instantaneous mixing concept was used to simulate the steady state of turbulent plane jet with combustion. The probability density function description of the fluid elements in a turbulent reacting flow could properly explain the turbulent flame zone structure and the turbulent transport of heat, momentum and chemical species even under the infinitely fast reaction rate assumption. The calculated distributions of the various moments of the turbulent combustion field were found in good agreement with the available experimental data. The dynamic behaviour of combustion in the turbulent field could be better understood via the probability density function description of the present turbulent kinetic theory approach.

Donald Willis Douglas, American aviation pioneer has died in California, after a long period of declining health.

EACH September the eyes of the aeronautical World turn towards the S.B.A.C. Air Display and Exhibition with interest unequalled by any other event. It is fitting that the Display is now held each year at the airfield of the Royal Aircraft Establishment, one of the world's most prominent aeronautical research centres. This interest becomes increasingly keen too, as the preview day comes closer, because new prototypes of unorthodox designs often appear a short time before the Show to illustrate the results of years of careful planning, development and research of the particular company. These designs often mould the path of progress for smaller countries without the economic resources to forge the way ahead alone. Most British citizens are very proud of their country's place in aviation today, both in the military and civil fields. This is understood by most foreigners because it is clear that Britain has won a place in aeronautical development second to none.

The purpose of air-intake duct used in combat aircrafts is to decelerate the inlet flow and concurrently raise the static pressure recovery at the compressor inlet. Because of side-slip movement during sharp maneuvers of the aircrafts, the airflows ingested into twin air-intake ducts are not same and symmetric at its two inlets but are asymmetric in nature. The asymmetric inlet flow conditions at the twin air-intakes thus caused instabilities and deteriorated aerodynamic performance of aircraft components such as compressors and other downstream components. This study aims to investigate the flow control in a twin air-intake with asymmetric inflows.

The continuity and momentum equations are solved with second-order upwind scheme for computing finite-volume method-based unsteady computational fluid dynamics simulation.

Performance parameters are deteriorated with the increase of inflow asymmetry in the twin air-intake duct. Slotted synthetic jets are used to manage flow separation, thereby increasing aerodynamic performance of the air-intake. A variety of vortical structures are generated from the rectangular slots, convected downstream of the twin air-intake. The use of slotted synthetic jets increases static pressure recovery by 64 per cent whereas reducing total pressure loss coefficient by 63 per cent, distortion coefficient by 58 per cent and swirl coefficient by 55 per cent which is an indicative of better aerodynamic performance of twin air-intake.

The study stresses the need of robust flow control technique to improve the performance of combat air-intake system under extreme maneuvering conditions. The results can be useful in designing air-intake satisfying the stealth features for modern combat aircrafts.

At the dawn of the twenty-first century, Boeing and Airbus, the leading manufacturers of large aircraft, were locked in a battle for market share that drove down prices for their new planes. At about the same time, the two industry heavyweights began developing new aircraft families to address the future market needs they each projected.

Aircraft take many years to develop, so by the time the new planes made their inaugural flights, significant changes had occurred in the global environment. First, emerging economies in the Asia-Pacific region and elsewhere were growing rapidly, spawning immediate and long-term demand for more aircraft. At the same time, changes to the market for air travel had created opportunities for new products. These opportunities had not gone unnoticed by potential new entrants, which were positioning themselves to compete against the market leaders.

In October 2007, the Airbus superjumbo A380 made its first flight. The A380 carried more passengers than any other plane in history and had been touted as a solution to increased congestion at global mega-hub airports. Four years later the Boeing 787, a smaller long-range aircraft, was launched to service secondary cities in a point-to-point network.

The case provides students with an opportunity to analyze the profit potential of the global aircraft manufacturing industry in 2002 and in 2011. Students can also identify the actions of participants that weakened or intensified the pressure on profits within the industry.

Audio format (.mp3 file) available with purchase of PDF. Contact cases@kellogg.northwestern.edu for access.

The purpose of this paper is to compare twin engine civil turboprop aircraft with their jet engine counterparts; to simplify the preliminary design process and the initial evaluation of twin civil turboprop aircraft; to include noise level consideration in the preliminary design; and to form a current database of design parameters for representative civil turboprop aircraft.

The paper finds linear correlations between key design parameters. It compares the corresponding correlations for turboprop and jet engine aircraft.

The paper finds direct linear relationships between design parameters including noise levels; simplified preliminary design process; and differences in the sensitivity of design parameters between turboprop and jet aircraft.

The turboprop aircraft database needs to be expanded. Also, investigation of non‐linear relations between design parameters is a next step.

Quick assessment and comparisons of existing designs is an outcome. Also, the preliminary design process is simplified and expedited. Lastly, noise regulations can affect the design right from the beginning and not at a later stage.

New correlations which simplify the current procedures for preliminary design of twin civil turboprop aircraft. In addition, the noise is included right from the beginning of the design. Direct comparison between turboprop and jet aircraft afforded via their correlated preliminary design parameters. Finally, a database of twin turboprops is formed with specially selected aircraft that are current and cover a wide spectrum of sizes.

AT the present time, it is depressing to write an article on the French Aircraft Industry. At the end of World War I, it was the first in the world and the famous names of the illustrious air pioneers were still to the fore. Now, on the contrary, it is far behind the American, British and Soviet industries.

SYSTEMATIC experiments carried out by the Dornier‐Werke for several years (for the purpose of investigating flight properties and the quantities of importance for flight performance) included, during 1935, point‐to‐point measurement of the downwash field in front of the tail unit of the Do 17, using twin tube pressure recorders. These flight measurements showed that the stability components of the two halves of the tail plane are not the same on account of the different downwash components produced by rotation of the slipstream. The conclusion that the stability of the aeroplane could be raised by symmetrical arrangement of the airscrews, in accordance with the more favourable starboard side, was well founded, and it was soon recognized that this precaution, in conjunction with the other well‐known advantages of symmetrical direction of rotation of the engine units, is one of the most effective methods for improving the flying properties of two‐ and four‐engined aircraft. This knowledge, which in the meanwhile had been confirmed in various places by wind tunnel tests induced the Dornier‐Werke to generally introduce counterrotating power plants for twin‐engined aircraft.

THE purpose of this article is to indicate the developments in aircraft that have appeared since the first post‐war S.B.A.C. Display of 1946. Now is perhaps the time to pause and consider progress in British aviation, particularly as the first turbo‐jet air liner, the Comet, has entered service, the first turbo‐propeller aircraft, the Viscount 700, is being manufactured in quantity, and production orders have been placed for the Hawker Hunter swept‐wing fighter and the Gloster G.A.5 Delta. These aircraft represent a few of the British types evolved in the post‐war period and demonstrate aeronautical advancement.