Search results

The air data system of an aircraft includes, amongst other items, the airspeed indicator, altimeter and machmeter all of which derive their readings from measurement of air pressures. The instruments are designed on the assumption that they will be fed with pressures from the undisturbed free‐stream in which the aircraft is flying; this is not generally the case. In flight the aircraft disturbs the air mass and in doing so causes a pressure field around itself which produces the forces necessary for lift and control. The pressure sensors which detect the airstream pressures may be located within the aircraft pressure field and the pressures transmitted to the instruments may not correspond to the free‐stream pressures; if this is so then the instrument indications will be in error.

THE development of aircraft penumatic equipment has progressed so satisfactorily in recent years that actuation of vital services by means of compressed air is becoming increasingly popular. In this brief review of developments to date an attempt will be made to show how the air which has been made available as a result of compressor improvements is utilized and by way of introduction it may be of interest to recall some of the bold experiments which were made in earlier years.

THE COMPLEXITY of modern pressurisation and air conditioning systems for jet aircraft have led increasingly to the practice of selecting a single contractor to design and integrate all of the components into a compatible system tailored to the mission requirements of the aircraft.

THE airframe systems division of Lucas Aerospace are involved in producing the high lift and wing sweep control unit for which the design rights are shared with Microtecnica SpA who hold the contract.

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 purpose of this paper is to investigate the autoclave-pump pressured water distribution system. Pressured water is used in many manufacturing processes, as a raw material or as a service fluid for different applications.

The performances and the total installation costs of such systems are strongly related to its design and to its decision variables definition. The authors first identify the independent variables (i.e. the decision variables) and the dependent variables of the system and, second, propose a techno-economic mathematical method able to determine its minimum installation cost with an integrated approach.

The trade-off between the autoclave installation costs versus the pump installation costs is demonstrated. A sensitive analysis of the cost of the system as function of its decision variables has been performed to propose a practical graphical analysis tools to proper design the integrated pump-autoclave pressured water distribution system.

Many previous researches focus only on the pump system optimization or in the tank system optimization without an integrated approach. The wide utilization in industry of the autoclave-pump pressured water distribution system together with the lack of similar contributions in this area enforces the value of this research.

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.

The purpose of this paper is to study the pressure response characteristics of the cartridge electromagnetic relief valve, which offers the problems caused by low pressure response and low efficiency in hydraulic plate shearing machines.

First of all the mathematical model of the cartridge electromagnetic relief valve is deduced to analyze the influence of the relevant parameters on the system pressure response. Then experiments are conducted to research the dynamic characteristics on building and relieving pressure. Through comparison of theoretical and experimental research, the results are found.

The results show that the input flow, working pressure, diameter of adjacent damping hole, and spring stiffness of the main valve have great influence on building pressure of the system, and have no influence on relieving pressure, while diameter of damping hole of control cover plate has influence on the building and relieving pressure of the system.

The research results provide powerful theoretical support for the parametric design of the cartridge electromagnetic relief valve in the hydraulic system of plate shearing machine.

The paper aims to develop a system and measuring method for investigating the dynamic pressure behavior of compression garments.

The dynamic pressure behavior measurement, realized by use of the self‐designed system, is a direct measuring method, which is based on a rigid hemisphere with five pressure sensors distributed on its surface. The dynamic pressure is measured over time under the process of fabric 3D deformation. The pressure distributions at the basic five sites are accepted as the measuring results. The dynamic stiffness index can be calculated from dynamic pressure profile and 3D deformation of compression garments.

The measuring system records the pressure‐time curve and pressure‐deformation curve. The dynamic pressure stiffness index expresses the change in pressure owing to the change in elongation of compression fabrics. The pressure measuring system and the index provide much information in the field of compression garment assessment.

Another characteristic that was not mentioned but important is pressure hysteresis, which can give the information about pressure decay when fabrics undergoing repeated stretch and relaxation. The influence factors of hysteresis and its role in compression garments also requires further research.

To determine and characterize the dynamic pressure behavior of compression garment under 3D deformation, this study develops a measuring system and defines a new index. The measuring system can be used in scientific research institutes and factories, contribute to optimize process parameters and quality control of compression garment.

The non‐destructive inspection of large concrete walls (e.g. dams, bridge pylons) with autonomous systems is still an unsolved problem. One of the main difficulties is to develop a very flexible platform, which is able to move and inspect horizontal and vertical surfaces safely, and which is fast and cost‐efficient. The purpose of this paper is to present a climbing robot designed with these attributes in mind.

This paper presents the Climbing RObot with Multiple Sucking Chambers for Inspection, which is designed for inspection of concrete walls. The propulsion system consists of three omnidirectional‐driven wheels for high maneuverability. The adhesion is performed by a vacuum system of seven controllable vacuum chambers and one large reservoir chamber. Pressure sensors and valves are integrated for controlling, which allows fast reaction on changing conditions.

The comparison of simulated results and a simple prototype indicates that the developed physical model is exact enough to estimate the efficiency of the proposed adhesion mechanism. The propulsion system has been tested extensively and allows high maneuverability on reasonably flat ground.

This paper introduces a climbing robot which will allow higher objectivity and reproducibility of inspections as well as safe working conditions for technicians. With such a machine one can check the building via remote control or semi‐autonomously.