A commercial aircraft programme has always been an undertaking with significant risk. Accurately estimating potential sales and production costs of these aircraft is an essential part of containing this risk. This paper addresses the cost estimating process and cost management of the latest Boeing programme — the 757.

Substantial resources are required for a new programme. The number of people involved, of course, varies with the stage of production, but Boeing will employ approximately 10,000 at peak production rates. In a typical Boeing programme, a network of over 1000 suppliers of material, parts and equipment will employ another 20 000 people at peak production so that total employment is in the 30 000 range.

This paper deals with how lasers work, their applications generally and their specific applications to aircraft.

The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation. The theory was written by Charles H. Townes and Arthur L. Schalow in 1958. The co-authors of the theory hold the basic patent on lasers.

In 1960 Theodore H. Maiman, of the Hughes Aircraft research laboratories, practically produced what was the most concentrated energy source known to man. A beam able to cut through a sheet of steel one third of a centimeter thick that does not contain enough energy to boil an egg.With this practical demonstration Maiman had made the first laser work.

Universities should be able to do two things which industry may not be able to do, and which should be valuable. We are supposed to be able to have time to think instead of continuously meeting deadlines (this is hardly true anymore) and so we can:

1. 1. Take a risk and embark on a novel idea which may not come off. If the gamble works then we publish and promote it for the general good.

2. 2. Recognise that industry has to meet deadlines, and often produce an answer to a problem which is only partially understood. We can then look at the problem in depth, and with better understanding point the way to future development.

Forward Swept Wings have a number of advantages over Aft Swept Wings which have been appreciated for a number of years. In the past, however, their use has been restricted to limited degrees of sweep because of the severe weight penalty necessary to prevent aerolastic divergence. Recently, it has been shown that the outstanding directional properties of fibrous composites could help overcome this problem by adequate selection of ply orientations and laminate thickness distribution of the wing skin.

Cabin capacity is the number of seats available. If there are too few seats too many potential passengers are turned away, potential revenue is not realised and the proper service is not provided to the travelling public. If there are too many seats a lot of them will be unused when demand is low and costs will be high in relationship to revenue.

Cabin capacity is a consideration when aircraft are being procured but at that stage it need not be calculated very precisely. Once the aircraft is in service quite small adjustments may make the difference between profit and loss, a particular problem being where to divide the cabin between the different classes.

As a preview to the main discussion, the role of the Twin Gyro Unit as a component part of the weapon's guidance system is first described. The reader will appreciate that there are as many types and configurations of gyro units as there are weapons and a full treatment of the subject would be beyond the scope of this paper. For the purposes of the discussion that follows, the gyro unit chosen is the two degree of freedom, electrically driven, Rotoraced displacement gyro, as used on the Sea Eagle, Anti Ship sea skimming missile.

The technique of geometric programming is applied to the design of optimum wing bend boxes in sheet-stringer-rib construction. The work extends the previous application in multi-spar design and the results for the different configurations are compared. Closed-form design equations are given for the case of buckling constraints whereas more complex formulations with stress constraint were solved by computer.

The role of the International Civil Aviation Organisation (ICAO) in developing standards and recommended practices for communication, navigation and surveillance systems is well known. The emphasis is on system characteristics and the definition of airborne equipment is limited to essential characteristics. For many years, the world’s airlines have collaborated in the Airline Electronic Engineering Committee of ARINC to produce engineering characteristics to ensure interchangeability and hence freedom of choice in their selection of airborne equipments. Thus ‘box’ dimensions, types and pin connection, interfaces cabling, coding etc are covered.

For the electronics industry designing equipment to meet the needs of both the aircraft constructors and their customers, the airlines and the Airworthiness Authorities responsible for the certification of equipment installed in passenger carrying aircraft more detailed specifications are essential. This problem was recognised in the USA and a solution was found in the formation of the Radio Technical Commission for Aeronautics (RTCA). With the direct support and involvement of USA Government Departments, the Electronics and Aircraft Construction Industry, the Airlines and General Aviation operating as ‘Special Committees’ of experts, RTCA developed Minimum Performance Standards. These documents are used by the FAA as the basis for equipment certification.

It has always been important for military commanders to be able to rely on their equipment being available to them during a conflict. Some recent published figures, however, showed that two modern fighter aircraft were only available for missions for 47% or 56% of the time.

A simple operation simulation model was derived to show an aircraft's sensitivity to the main availability parameters. This model can be applied to any aircraft type provided that the necessary inputs can be calculated. The simulated operations were as realistic as possible, although many assumptions had to be made.

For reasons of national security it was not possible to relate this study directly to any current service aircraft, so a design project study has been used as the baseline aircraft in the simulation model. This aircraft was the 1980 Mini-CAS, developed at Cranfield Institute of Technology. This was used because all the necessary data were available or could be estimated with reasonable confidence and also the operating conditions are comparable to a number of current service types employed in the Close-Air-Support role. Thus the simulation was kept realistic and the results and conclusions are directly applicable to real and projected designs. Subsequent work checked the validity of the model by simulating an A-10 exercise and Sea Harrier operations in the Falklands conflict.

The Operations Simulation Model proved to be a satisfactory means of assessing the effectiveness of a force of aircraft under war-time conditions. It was far more flexible than the Availability and Mission Readiness equations commonly used to compare the in-service performance of aircraft and highlighted areas where resources could best be concentrated to improve availability. Further improvements are necessary however, to take account of spares shortages and the effect of adverse weather.

Complex electronic systems are structured into functional units, printed circuit boards and components. During the manufacturing process testing starts at the component level and is carried out progressively at PCB, functional test and finally total system level.

When the equipment is in service, the reverse process is followed. That is, at the system level the suspect unit is diagnosed and replaced. This unit is then tested and if faulty diagnosed to the faulty board. This in turn is tested to find the faulty component. The testing of functional units, boards and complex components (referred to here as the ‘box’) is carried out on Automatic Test Equipment both at the factory and field level. In each case the test problem needs to be addressed during design to ensure that adequate access is given to the internal function of the item.

It was recognised over 40 years ago that sweeping the wing of an aircraft could be used to offset the effects of compressibility. However, by no means all of the earlier swept-back wing aircraft used sweep for performance reasons. Some, such as the Horten tailless gliders built in Germany, had swept back wings to ensure necessary longitudinal stability. Likewise the Messerschmitt Me163 rocket interceptor employed a swept back wing as an essential feature of its layout but it operated at a sufficiently high Mach number for the beneficial aerodynamic effects of sweep to be of value. From the compressibility point of view, the wing may be either swept back or swept forward, and the idea of forward sweep was incorporated in the Junkers Ju287 jet propelled bomber (Fig. 1). The 18 degrees forward sweep enabled the wing-fuselage intersection to be positioned behind the deep bomb-bay and thus avoided a difficult structural cut-out problem. A more elegant solution to the same difficulty was the ‘crescent’ swept-back wing layout for the Handley-Page Victor bomber.

My brief is to talk about flight mechanics. But flight mechanics covers all aspects of flight, including aircraft performance, operation and integrity. To limit this talk, flight mechanics is restricted to those aspects of flight dynamics which are concerned with the controllability of aircraft. Even so, it is a wide topic essentially interdisciplinary, embracing inertia, aerodynamics, structural dynamics, engines, hydraulic and electrical systems, instrumentation and avionics. Furthermore, the term ‘aircraft’ needs to be interpreted in the broader sense of referring to aeroplanes, missiles and spacecraft. In the spirit of this meeting, we are looking at contributions from universities in the past and identifying current centres of activity.

The arguments for the trend from tail-wheel to nose-wheel undercarriage configurations, which appear to be completely pervasive so far as current aircraft designs are concerned, are examined in the light of modern technological developments.

It appears that many of the problems that have led to the demise of the tail-wheel undercarriage configuration are surmountable in an actively controlled, undercarriage management system. There seems some prospect of performance gains from a system of this kind but a more detailed study than is attempted here is necessary to determine if these performance gains can offset the added complexity of the undercarriage management system to result in more cost effective designs.

The RAE Boundary Layer Tunnel is an open return facility driven by a 100 hp ventilating fan. It is provided with interchangeable working sections of cross-section either 1·2m × 0·3 m or 0·6 m × 0·6 m. There is no diffuser downstream of the working section which exhausts directly into the test room. The tunnel was arranged in this way to avoid restrictions on the design of the working sections and also in order to enable control of the pressure in the working section by means of a screen over the exit. This control made it possible to bleed flow from the working section, to avoid unwanted separations, for example, or to provide some special flow characteristic.

More than ten years of development have gone into the Rolls-Royce wide-chord fan, which will provide a 2½ per cent fuel saving when it enters service in 1984. This new and highly efficient fan is one of the advanced features of the 535E4 engine, which will have a fuel consumption 10 per cent better than that of the initial Rolls-Royce engine for the Boeing 757, the 535C.

How has this advanced fan been developed and what are its advantages? This article surveys the reasons for its development and the factors involved in this technical advance pioneered by Rolls-Royce.

The TiltRotor concept combines the wing of an aircraft with the rotors of a helicopter. The result is a VTOL aircraft which is fuel-efficient in both cruise and hover. It can be thought of as a turboprop aircraft which can take off and land vertically, but it is also an advanced rotorcraft which has twice the speed and range of present-day helicopters.

When presented with yet another VTOL aircraft proposition, many people are quick to look for its shortcomings. The most obvious is the empty weight penalty. As an aircraft, the TiltRotor is burdened with a helicopter’s transmission, rotor, and controls. As a helicopter, the TiltRotor carries along an aircraft wing and controls, with a small hover efficiency penalty imposed by the high disc loading.

The exact solution to the stability of a simply supported rectangular plate loaded along two opposite edges by several equidistant point loads is presented. Criteria are derived which, if met, permit the true stress state throughout the plate to be radically simplified.