CoA. Memoranda
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Item Open Access Resistance network simulation of semiconductor systems(College of Aeronautics, 1964-09) Loeb, H. W.1. Introduction A basic problem in the design theory of semiconductor systems such as p-n junction devices relates to the determination of the spatial variation of electrostatic potential, 4, of electric field intensity, and of mobile carrier (hole, electron) concentrations, p and n ... [cont.].Item Open Access Design project 1968/9: report of assembly process committee(College of Aeronautics, 19) College of Aeronautics, (Cranfield)This report describes the approach to the design of an automatic versatile assembly machine of modular construction. Details of the design of the conveyor module, the platen upon which the assembly is mounted and the platen motivation mechanisms are included. It also includes the assembly system that has been applied to the assembly of an electrical contact block. This entailed a machine layout, the re-design of a component and the design and specification of appropriate fixing heads.Item Open Access Automatic assembly design project 1968/9: report of assembly analysis and coordination committee(College of Aeronautics, 1969) Shaw, C. R.The present assembly method and component parts of a chosen product are analysed. The design of components is investigated, and a workstation sequence is proposed based upon the modified components. A pick-and-place head is designed, versatility being the main design criterion. A functional check mechanism is designed.Item Open Access Design project 1967/8: the design of a numerically controlled precision turning / milling machine(College of Aeronautics, 1968) Powell, N.This report outlines the design of a precision turning machine with a limited milling facility which incorporates a fluidic numerical control system. It contains an introduction to the project together with summaries of the reports of the Technical Survey, Concept and Configuration, Design, and Control committees.Item Open Access First interim report on fluid diodes(College of Aeronautics, 1969-10) Taylor, A. F.A description of the various forms of fluid diode and report of tests done on a breadboard unit leading to the manufacture and testing of a prototype 1 14u vortex diode. This work was carried out under contract for Flight Refuelling Ltd. (ref. order no.D.15795 of 2.5.69) and is the first of a series to cover a preliminary study of fluidic and allied devices in aircraft low pressure fuel systems.Item Open Access Application of inflated structures to hovercraft annual survey 1968-69: inflated structures report C1206/3(College of Aeronautics, 1969-09) Richards, D. M.1.0 Introduction This report surveys work carried out in the Department of Aircraft Design at the College of Aeronautics, Cranfield, in accordance with the terms of Ministry of Technology contract reference PD/28/045/ADM, College of Aeronautics reference 0.1206. The period covered by this report extends from 1st October 1968 to 1st October 1969, which constitutes the first complete year of operation under the contract terms. The reporting procedure agreed with Mintech is that individual research topics shall be separately reported in the form of technical memoranda, and that comprehensive surveys of a descriptive nature shall be submitted at regular intervals.Item Open Access Some preliminary suggestions on the standardisation of data collection procedures from U.K. commercial hovercraft operators and an initial study into the derivation of a standard method for estimating the operating costs of hovercraft(College of Aeronautics, 1968-08) College of Aeronautics, (Cranfield)INTRODUCTION This report is a summary of the ground covered during a 6 month pilot study encompassing a number of aspects of hovercraft operations. It is hoped that the experience gained. during this period of study will enable more specific tasks involving much more detailed analysis of particular aspects of operations to be carried out. a) the nature of data available on past operations; b) expected future data; c) topics expected to yield the greatest benefits to all parties concerned (i.e. Cranfiela, Mintech., the Operators and the Manufacturers, present and prospective) both in the short and long term: and a) manpower available. Unfortunately the latter restriction proved more severe than had been initially envisaged. Fields of study considered were as follows: (i) A study of the Problems involved in the derivation of a Standard Method for Estimating the Operating Costs of Hovercraft. (ii) An attempt to Standardise the data collection proceedures from the various current U.K. Operators. iii) An analysis of all currently available data. iv) An investigation into the possible use of Automatic Data Processing techniques for the collection and analysis of operating data. (v) An analysis of the causes and effects of delays and cancellations in current scheduled operations. (vi) A study of the traffic carried on and the demand for current scheduled services, and the effect of varying fare structures on this.Item Open Access Design project 1968/9: management report(College of Aeronautics, 1969) College of Aeronautics, (Cranfield)1. INTRODUCTION The design of an automatic assembly machine with versatility in application was undertaken as a group project by post-graduate students attending a course in production technology. This report summarises the work clone and conclusions reached during the project. In addition there are available five other reports which describe the designing of different areas of the machine in full detail (refs. 1 to 6). There is also the report of a technical survey which was carried out to investigate industrial requirements for automatic assembly. In order that this report may serve as a guide, a summary of the content of each of the other reports is included.Item Open Access Automatic assembly design project 1968/9 : Report of economic planning committee(College of Aeronautics, 1969) Jones, P. V.; Pettitt, M. E.; Kaloo, U.Investigations into automatic assembly systems have been carried out. The conclusions show the major features to be considered by a company operating the machine to assemble the contact block with regard to machine output and financial aspects. The machine system has been shown to be economically viable for use under suitable conditions, but the contact block is considered to be unsuitable for automatic assembly. Data for machine specification, reliability and maintenance has been provided.Item Open Access The effect of grain size on workhardening and superplasticity in Zn/0.4% Al Alloy(College of Aeronautics, 1969-06) Naziri, H.; Pearce, R.Superplasticity*requires, amongst other things, a metal with a grain-size in the range 0.5-5μ. Theories of SP invoking dynamic recovery require that the cell-Size of the substructure for the alloy in question is larger than the SP grain-size, so that gliding dislocations are always annihilated in the grain boundaries and workhardening cannot occur (1,2). .Thus the grain-size is critical, and for a given set of conditions, there must be a grain-size greater than which SP cannot be achieved.Item Open Access Anisotropic superplasticity(College of Aeronautics, 1969-06) Naziri, H.; Pearce, R.Anisotropy has already been mentioned in connexion with SP. Johnson et al (1) have shown that specimens of circular cross-section, machined from hot-rolled SP Zn/Al eutectic and eutectoid plate, become elliptical on straining in the rolling direction, while the fine-grain Zn/Al eutectoid produced by the quench-4 spinoidal decomposition method did not.Item Open Access Optimum stiffness inflated mattress beams(College of Aeronautics, 1969-09) Webb, J.This report considers primarily the relatively short cantilever type of inflated matresss beam, currently being employed as sidebody structure on some hovercraft. The rib pitch for optimum stiffness/weight of such beams is determined, and it is shown that thin ribs, closely pitched, with relatively thick skins provide the most efficient structures.Item Open Access The time-dependent mechanical properties of fibre reinforced polymers(College of Aeronautics, 1969-09) Dootson, M.1. General Progress The six months from April to September 1969 have been spent mainly in consolidating the work of the previous eighteen months. Firstly, due to major servicing problems, it became necessary to redesign the resin impregnating head of the filament winding machine. By the removal of all moving parts from the vicinity. of the resin, these servicing problems have been completely overcome. Using the redesigned machine many sheets of high quality glass reinforced epoxy resin have been produced. A sophisticated version of the spring mounted lateral extensometer described in Progress Report No. 3 has been designed and tested. Six of these have now been produced and are now in service yielding satisfactory results. The majority of the period has been spent in setting up the tensile creep testing machines. This has been necessitated by the discovery that errors of up to 10% in creep compliance have been obtained through misalignments of the loading linkages of the order of .01 inch. All the apparatus is now functioning correctly and more creep results for uni- and bi-directionally reinforced specimens are being obtained. Included in these current creep results are not only values for creep compliances but also for the creep contraction of these specimens.Item Open Access The measurement of biaxial strains in coated fabric materials using the disc-replica method(College of Aeronautics, 1969-09) Webb, J.; Richards, D. M.A method of measuring biaxial strains in coated fabric type materials is presented whereby the strain is deduced from the distortion of a circular impression made on the material. The impression is placed on the material when loaded, enabling all measurements to be made with the material in its relaxed, unloaded, state.Item Open Access Project report on Milton Keynes(College of Aeronautics, 1969) College of Aeronautics, Transport Short CourseIntroduction 1.1.1 This is a project report written by the members of the College of Aeronautics short course held between 24th February and 7th March, 1969. 1.1.2 An Interim Report was presented by the Planning Consultants to the Milton Keynes Development Corporation in December 1968„ The report is not a definitive plan for building the City, but it has been prepared through a process of consultations between the Consultants, the Corporation members and staff, and many of the authorities and departments in central and local government who will be responsible for various aspects of the City. The report can be taken as representing the strategic approach of the Corporation towards the now City at this stage of the planning process, but it is not intended to submit proposals for approval by central and local governments until the complete plan is produced at the end of 1969. 1.1.3 The Interim Report has been published at this stage partly to enable limited development work to be started in advance of the Plan, and partly to encourage discussion by the public and organisations and authorities concerned. It is recognised that new views and further examination may make practicable changes desirable and necessary.Item Open Access Automatic assembly design project 1968/9: Report of component supply and separation committee(College of Aeronautics, 1969) Gray, A. F.; Hayes, D. A.; Jones, P. V.; Scarr, A. J.This report outlines the techniques for automatically feeding the components of an electrical contact block and describes the design of a feeding system for each component. All components of the contact block were initially analysed for automatic feeding and redesigned where necessary. Existing feeding methods were examined and consideration was given to their versatility. Decisions were then made as to the feeding system for each component.Item Open Access Automatic assembly design project 1968/9: report of technical survey committee(College of Aeronautics, 19) LeHunte, G. G.; Stout, K. J.; Charnley, C. J.; Powell, E. A.An Industrial survey has been carried out to determine the desired features of an automatic as machine. A questionnaire was circulated to industry and the results of the 38% response obtained were analysed and plotted. From these, conclusions were drawn as to the industrial requirements of an assembly machine.Item Open Access Vibrations of the propeller shaft and the rear axle of a passenger car(College of Aeronautics, 19) Egbuson, A. K.; Hodgetts, D.; Hodgson, R.Digital analysis of the free-free bending vibrations of a propeller shaft and a beam-type rear axle are compared, for different theoretical models, with the results of rig tests. The relative importance of distributed mass, the coupling between the bending and torsional modes and the half shafts of the rear axle are discussed. The relation between the work completed and the programme of work in progress is given briefly at the end of the report.Item Open Access Some aspects of electro-chemical grid-marking(College of Aeronautics, 1969-04) Pearce, Roger; Drinkwater, Ian C.Introduction The value of fine grids, electromarked (1) on to metal sheets before pressing, so that the type and magnitude of the strain developed in the critical region of the pressing can be assessed, is undisputed. Keeler (2), Meyer and Newby (3), and Goodwin (4), have all discussed practical applications of this technique and Palmer (5) has reviewed the field and introduced the concept of a relative safety factor (MSF). However it may be useful to see what this 'mark' consists of, how the marking affects the subsequent metal performance, what the limitations of the process are and other peripherical issues. It is these aspects of the process which is the concern of this paper.Item Open Access The pyrolytic degradation of epoxy resins in nitrogen at 400 to 700 degrees C(College of Aeronautics, 1969-03) Bishop, D. P.; Smith, D. A.The thermal degradation of a bisphenol-A based epoxy resin (EP 274) cured with 4,4’ -diaminodiphenyl methane (DDM) and with phthalic anhydride (PA) was studied using pyrolysis gas chromatography. Conclusive evidence for some of the degradation mechanisms of these resins was obtained by pyrolysing samples containing various 14C labelled groups and analysing the products using a combined gas chromatography and radiochemical technique.