bluuebunny/crossref_metadata_2025 huggingface dataset:
Mean reversion and autocorrelation in profitability of Illinois farms
Authors: Phillips Jill M. , Katchova Ani L.
Published: November 2014

Economic theory implies that firms in a competitive market will adjust to long‐run equilibrium levels of profitability, resulting in mean reversion of profitability. Partial adjustment models are applied to farm‐level data from Illinois to test for mean reversion and autocorrelation in profitability. Results show that farm businesses revert to individual levels of expected profitability at an annual rate of 0.5, while the annual rate of negative autocorrelation is 0.175.
Cognitive biases and design effects in experimental auctions
Authors: De Steur Hans , Vanhonacker Filiep , Feng Shuyi , Shi Xiaoping , Verbeke Wim , Gellynck Xavier
Published: November 2014

Purpose

– Experimental auctions are widely used as a non-hypothetical value elicitation method to examine consumer preferences for novel, controversial foods. However, despite its advantages over hypothetical methods, its practice might lead to a wide variety of biases. The purpose of this paper is to provide a list of key cognitive biases and design effects in food auction research and to deliver scientifically underpinned procedures in order to assess, control and reduce them. Its applicability and relevance is examined in auctions on willingness-to-pay for folate (GM) biofortified rice.

Design/methodology/approach

– Based on auction literature, a list of 18 biases has been developed. Experimental auctions were conducted with 252 women from Shanxi Province, China to test the occurrence of eight biases, while demonstrating measures to reduce the risk of ten biases.

Findings

– The results lend support for three information-related effects, i.e. confirmation bias, conflicting product information effects and a primacy bias, but not for a multiple-good valuation effect, a panel size effect, a trial winner effect and time-related sampling biases. Furthermore, there are no clear indications of social desirability bias, auction fever and a false consensus effect.

Research limitations/implications

– This study emphasizes the need to take into account, and measure the risk of various biases when developing, organizing and interpreting experimental auctions. Future research should further extend the list of biases and validate the study findings.

Originality/value

– By using a highly topical subject, this study is one of the first to address the potential risk of cognitive biases and design effects in experimental (food) auctions.
Fertilizer industry subsidies in China: who are the beneficiaries?
Authors: Li Sheng , Zhang Yaoqi , Nadolnyak Denis , David Wesley John , Zhang Yifei
Published: November 2014

Purpose

– Since 2004, subsidies increased by 670 percent in the Chinese fertilizer industry to reduce the farmer's burden. The purpose of this paper is to assess whether subsidies benefit the target groups, the fertilizer subsidy distribution pattern and benefit allocation pattern among fertilizer producers and other sectors were investigated.

Design/methodology/approach

– The Muth model is extended to evaluate the impacts of a subsidy on multi-stage markets.

Findings

– It is found that the total benefits from the policy are about RMB 7.7 billion yuans. The fertilizer suppliers gain about RMB 51 billion yuans from the favorable policy with mean subsidy incidence 0.8 and capturing about 70 percent of total surplus.

Social implications

– The results suggest that transferring parts of subsidies to the non-fertilizer sectors could be considered an efficient way to redistribute welfare indifferent sectors.

Originality/value

– This study first use the equilibrium displacement model to quantity the distribution of fertilizer subsidy in a vertical market in China.
Food prices and inflation dynamics in China
Authors: Zhang Chengsi , Meng Chunming , Getz Lisa
Published: November 2014

Purpose

– China has witnessed low and stable consumer price inflation in conjunction with high and volatile food price inflation over the past decade. The purpose of this paper is to examine questions about whether or not the link between consumer price inflation and food price inflation has weakened and the determinants of consumer price inflation.

Design/methodology/approach

– This paper explores these questions by estimating error correction terms for monetary and external sectors using the Johansen cointegration method.

Findings

– Empirical results suggest that the link between consumer price inflation and food prices has not been weakened, food price inflation, especially cereal price inflation, remains a significant driving force for overall consumer price inflation, and international food prices also play a significant role in determining China's inflation dynamics.

Originality/value

– The paper construct a multivariate dynamic model that features the link between consumer price inflation and its potential driving variables. It also develops error correction models for food price, non-food price and consumer price inflation, which can accommodate dynamic interactions among the underlying variables.
Creative marketing and management science
Authors: VOGEL E.H.
Published: November 2014

CREATIVE marketing involves in general terms systematically questioning the assumptions behind marketing strategy and tactics and using the best available technology in doing so. My company has been in a particularly good position to engage in such marketing because it is involved in selling to both consumers and industry. Such involvement gives us an opportunity to learn about marketing at a level of generality that is not available to many companies.
Teaching the Theory of 1st and 3rd Angle Orthographic Projection
Authors: Howarth A.D.
Published: November 2014

Last month Mr Macqueen's article dealt generally with solid geometry and industrial drawing. In the present article Mr Howarth, who is a member of the SBAC Committee on the Training of Draughtsmen, follows this with the development of 1st and 3rd angle projection in particular.
The behaviour of stainless steel in sea‐water
Authors: Maritimer
Published: November 2014

In view of the controversy in this journal on the behaviour of stainless steel in sea‐water it may be relevant to take a critical look at the problem.
Film‐forming phosphating copolymers in the corrosion protection of ferrous and non‐ferrous metals
Authors: Lowe P.
Published: November 2014

ALTHOUGH the practice of depositing crystalline phosphate coatings (iron, zinc, manganese) on ferrous metals and aluminium is well accepted, and although ‘phosphating compositions’ of the resin/phosphoric acid/polar‐rich solvent type are now in fairly widespread use, their function is merely to act as a rust inhibitive ‘bridge’ between the metal surface and the subsequent organic coating.
NUMERICAL SIMULATION OF THE THERMAL OXIDATION OF SILICON
Authors: Gadiyak G.V. , Korobitsina J.L. , Kranarenko V.I.
Published: November 2014

Computer code complex for the thermal oxidation of silicon is presented. There are one‐dimensional model and two‐ dimensional models:the model of viscoelastic oxide and the hydrodynamical models — an ideal fluid and a viscous fluid models. If nitride mask is absent, a one‐dimensional model is used.The influence of an induced stress on the diffusion and reaction is taken into account.
International Logistics Management at General Motors: Philosophy and Practice
Authors: Krapfel Robert E. , Mentzer John T. , Williams Rex R.
Published: November 2014

Corporate level examination of international logistics problems in formal fashion is a relatively recent occurrence at General Motors. International Logistics Operations (ILO) was created in June, 1977, and was made a part of Procurement, Production Control and Logistics Staff. The Director of International Logistics Operations reports to the Executive Director of Logistics and is charged with responsibility for the coordination of all international transportation activities.
Principles of Education and Training in Industry
Authors: Bellamy R.G.
Published: November 2014

The author, a member of the Industrial Training Council, analyses the essential purposes of education and training in industry and outlines the main features of a policy which would be applicable in any sizeable industrial undertaking. The photographs illustrate industrial and commercial training in the electricity supply industry.
Liberal Studies
Authors: MacLennan A.
Published: November 2014

This is more than a survey and evaluation of views on liberal studies, the author goes deeper, into the difficulties of the teachers concerned — all teachers. He examines the major subjects usually regarded as coming under this heading, and ends with some provocative thoughts on three highly important and controversial questions: how can liberal studies be fitted in? What are the implications for technical teacher training? And who provides the necessary impetus?
ASPECTS OF APPRENTICESHIP — 6
Authors: Lemoine R.
Published: November 2014

GEC's student apprentice selection procedure, which is centred on a group selection technique, has reduced wastage very substantially.
Teaching Engineering Drawing
Authors: Hansbury J.
Published: November 2014

IT IS NOW more than twenty years since the writer joined a first‐year ONC course and listened to the lecturer explaining the principles of orthographic projection. The front‐vertical and horizontal planes were the covers of the register case and the side‐vertical plane was the register itself. Even from this distance in time how simple and straightforward the exposition appeared to be. Within ten minutes of its starting this student was busy with his first drawing and never since then has he experienced any difficulty whatsoever with either first or third angle projection or with auxiliary views.
Thirty Years of Thick‐Sandwich Training
Authors: Marshall R.F. , McCracken J.G.
Published: November 2014

THE POST‐WAR PERIOD has produced some major changes in methods of training of professional engineers, one of the most significant being the widespread adoption of various forms of sandwich course aimed at closer integration of academic study and practical experience. The ‘sandwich’ idea is not, however, a post‐war development; in fact, a number of college and university courses have been run on similar lines for many years. These were the prototypes of the thin‐sandwich arrangements involving alternating periods, usually of about six months, in college and in industry which characterise the courses leading to the recently instituted Diploma in Technology.
THE TECHNICAL COLLEGE LIBRARY
Authors: Dearden J.A.
Published: November 2014

THE SPEED at which technical colleges are paying heed to the exhortations of Circular 322, issued by the Ministry of Education in April 1957, varies throughout the country according to local understanding of the need for college libraries. Fortunately for the future of technical education in Britain the importance of this aspect of training is at last being accepted — mainly through successful demonstration and thanks to the foresight of a few perceptive Principals and their Boards of Governors. Some discussion of the initial problems likely to revolve round such a library may be of assistance to others who have not yet entered the field.
Computer Training Equipment — an approach to the economic and educational problems of computer teaching
Authors: Melluish D.M.
Published: November 2014

THE STEADY increase in the number of electronic digital and analogue computers used in industry for scientific and commercial work has stimulated a demand for education in the computer field to be provided by colleges of technology.
The Machine‐Tool Laboratory — 1
Authors: Walker W.F.
Published: November 2014

This is an aspect of a college's work which offers greater possibilities for co‐operation with industry than most. The firms sending students benefit directly, but the laboratory can also become a centre for disseminating information on the efficient exploitation of existing and new machines. At the same time, with the help of the manufacturers it can become a force to be reckoned with in furthering progress in the machine tool industry
A Field Review of ‘O’‐level Chemistry Textbooks
Authors: Bassey Michael
Published: November 2014

In the first part of this field review, twenty textbooks used for teaching ‘O’‐level Chemistry were analysed in broad terms. In this article various aspects of these books are examined in greater detail
Background to '56 — Foreground to '61
Authors: MacLennan A.
Published: November 2014

Many people are not only bewildered by the complexity of technical education, but unaware of its aims and total significance. This is unfortunate — particularly if they are concerned with technical students — for such an awareness is basic to purposeful, understanding teaching. The author describes a recent study aimed at supplying this philosophical background. (Conclusion next month)
The Pattern since 1956
Authors: MacLennan A.
Published: November 2014

This continuation of the author's series of articles on the recent history of technical education in this country, deals in particular with the problems facing the colleges
English for Craft Students — 1
Authors: Lynn John
Published: November 2014

FEW people would dispute that craft students should do some written work. The trouble is, very often, that the subject matter provided by textbooks is not familiar enough for them to be able to write about it naturally. True, the subject matter they are familiar with is likely to be limited in extent, but its very familiarity helps in the surmounting of an initial obstacle, and the job of learning how to write usefully can then be tackled directly.
THE TECHNICAL SCHOOL
Authors: Brazendale A.H.
Published: November 2014

Opinions on secondary technical schools are varied and often strongly held but, as with views on comprehensive schools, it helps to have been inside one. Mr Brazendale, a Cambridge graduate in his mid‐twenties, has taught in secondary modern and grammar schools as well as the technical school he discusses here
THE LANGUAGE LABORATORY
Authors: Williams I.C.
Published: November 2014

Will it be the language laboratory that finally helps the English overcome their shyness about speaking foreign languages? Or is our linguistic laziness too deeply ingrained?
LETTERS & DISCUSSION
Authors: James A.J.
Published: November 2014

IN December 1961, an article appeared in TECHNICAL EDUCATION entitled “The New Burnham Technical Scales”. This discussion of the then new scales included the statement:
Flying and Landing in Fog
Authors: Rowe A.P.
Published: November 2014

THE need for providing means which will enable a pilot to fly and land an aeroplane in fog arises from the fact that aeroplanes depend for their sustentation on translational motion. If a satisfactory helicopter were evolved, fog would merely cause inconvenience and delay instead of constituting a grave danger, as it does to conventional types of aeroplanes.
A Course for Ground Engineers
Authors: Gilmore J.J.A.
Published: November 2014

IN the previous instalment of this article the composition, structure, and treatment of various metallic materials employed in aircraft construction were considered. It is now proposed to deal with the mechanical testing of these materials necessary to ensure that they comply with the requirements of the specification adopted by the designer.
The Use of Dimensional Relationships
Authors: Capon R.S.
Published: November 2014

IN Aeronautics as in other branches of science, applications of the “theory of dimensions” have been of great assistance, as the customary use of coefficients, which are in effect non‐dimensional variables, testified. In most text books of physics rules are given for obtaining dimensional relationships in any problem, but in practice the methods recommended are seldom used. The procedure suggested by the text books is recapitulated in Bairstow's Aerodynamics (p. 380), but the author adds, “After a little experience in the use of the method … it is possible to discard it and write down the answer without serious effort.”
Light Beacons for Night Flying
Authors: Hampton W.M.
Published: November 2014

IT is sometimes suggested with regard to aerial light beacons that when the weather is clear they are unnecessary in populous country, and when the weather is foggy the lights cannot be seen, and therefore are of little use under any conditions. This statement does not, of course, represent the true facts of the case, but it does indicate the vital importance of a study of the various questions relating to the transmission of light to great distances.
The Corrosion of Metals
Authors: Sutton H.
Published: November 2014

WHEN the use of metals in the construction of the more important parts of aircraft of the heavier‐than‐air type superseded the use of timber, a large number of practical problems were encountered, as might reasonably be expected. The reasons for the popularity of metal structures are readily appreciated by those who have had experience of wooden structures. An important property in any material employed in aircraft construction is that of permanence. So far as materials employed in marine aircraft are concerned, the task of supplying alloys to give the desired degree of permanence, together with the necessary mechanical properties, is not by any means an easy one. The corrosion‐resistance, in particular, is a property vitally affecting the suitability of a particular metal or alloy for use in marine aircraft. Most industrial metals corrode—i.e., enter into chemical reactions, the result of which is in effect the conversion of some of their mass into non‐metallic matter—on exposure to a normal inland atmosphere, and as a rule the rate of corrosion is much greater in marine atmospheres or in contact with sea water.
The Practice of Research
Authors: Alcock J.F. , Glyde H.S.
Published: November 2014

IT is the painful experience of all who engage in experimental work of a type to which they are not accustomed, that they may easily spend more time in rectifying faults in their equipment or technique than in producing useful data. Information on these points has, therefore, considerable value to the investigator, but the supply of such information has hitherto been scanty. One reason for this, as regards research on internal combustion engines, is that, except for Government Establishments, which are naturally uncommunicative, and Universities, whose work is mainly educational rather than experimental, there are few organisations which carry out research on a scale wide enough to amass a large body of experience. One such firm is Messrs. Ricardo & Co., Ltd., who have been engaged on work of this kind for the last fifteen years. The description in these pages of their Shoreham Laboratory, and of their experimental methods, should, therefore, be of use to many. The writers (who are on the staff or Messrs. Ricardo & Co.) realise that the requirements of experimental work vary enormously, and that methods which suit their needs may not suit the needs of others. They have endeavoured, therefore, to explain not only how things are done, but why they are done in that particular way, and thus to give their readers an insight into the factors governing the choice of method, which they can apply to their own particular problems.
Tunnel Tests on High‐Speed Seaplanes
Authors: Cowley W.L.
Published: November 2014

IN the early part of 1926, tests were carried out in the N. P. L. wind tunnels upon models of high‐speed seaplanes for the Schneider Trophy‐Competition in America. Owing to lack of time it was decided not to enter British machines for that contest, but the wind tunnel work was continued, as the Air Ministry wished to further the development of high‐speed craft. After the 1926 contest the Air Ministry decided to allow R.A.F. seaplanes to be entered by the Royal Aero Club, and to assist the Club in the competition in the following year. The high‐speed seaplane work was, therefore, again applied to machines for the Schneider Trophy Contest.
Compression‐Ignition Engines
Authors: Pye D.R.
Published: November 2014

The high‐speed engine cannot compete with these fuel consumptions on a b.h.p. basis, but on a basis of indicated power there is little to choose, under optimum conditions, as is seen by comparison of the data in Figs. 7 and 8.
Monospar Aeroplane Production
Authors: Martin Brian
Published: November 2014

THE following is a brief account of how Monospar machines are being made, rather than a description of a completely worked‐out production system, and also of the considerations which were borne in mind while the machine was being designed. These considerations can be grouped under three headings: Design, Production and Maintenance, and will be dealt with after a brief description of the whole machine, which may be of assistance in visualising how the components to be described are combined.
Torsional Instability in Struts
Authors: Pugsley A.G.
Published: November 2014

CERTAIN types of strut, when tested in compression, fail by twisting. In such cases the twisting occurs suddenly at some critical compressive load corresponding to the incidence of torsional instability. This kind of failure is found in tests of “thin” section struts, of angle or channel section, for example, and sometimes in tests of “open” section struts with lattice or other light bracing, and is ascribed to the low torsional stiffness of such struts. The failure is often accompanied by a distortion of the sectional shape of the strut due to some secondary instability of section, but attention is here directed to the primary torsional instability involved.
Self‐Straining in Aeroplane Structures
Authors: Fox James
Published: November 2014

THERE are many instances in aeroplane design where the structures contain tension cables. If the structure is a “pure frame,” any error in the “truing up” will not occasion any additional forces in the various members; the only effect will be a slight distortion from its correct configuration. If, however, the structure is redundant, it is necessary that these cables be cut (or adjusted as the case may be) to their exact length; if not, the two joints to be connected will have to be distorted, thus causing the structure to become strained before any external loading has been applied. Such a structure is said to be “self‐strained.” The forces in the various members, of course, depend upon the extent of the straining between the two joints concerned.
The Aluminium Bronzes
Authors: Marsh E.C.J. , Mills E.
Published: November 2014

Fig. 6 depicts the structural effects of tempering by heating for thirty minutes at 630 cleg. C., followed by cooling off in the furnace subsequent to the hardening treatment shown in No. 4. The reduced hardness is 190 V.P.N. This tempering treatment permits the transformation of the beta into alpha plus delta in such a manner that the hard delta constituent is evenly distributed throughout the mass. Thus a hard constituent is embedded in a soft matrix and this offers an excellent abrasion‐resisting material, together with considerable toughness. Higher magnification would show that the delta has commenced to spherodise, thereby preventing the growth of a lamellar structure, and reducing the possibility of fragility along the delta planes.
Boundary Layer Theory
Authors: Lyon H.M.
Published: November 2014

A STUDY of the flow in the immediate neighbourhood of the surface of a wing or body has often provided an explanation of apparent inconsistencies in the evidence obtained from tests in different wind tunnels or from model and full scale experiments. It is of the highest importance in investigations of critical changes in aerodynamic forces such as occur when a wing stalls, of interference effects and of oscillatory motions caused wholly or partially by aerodynamic forces.
Ferrous Metallurgy in Aeronautics
Authors: Hatfield W.H.
Published: November 2014

NEARLY twenty years have passed since the author had the pleasure of giving a paper on the same subject to this Society. Progress in the meantime as regards the means and art of flying has been not only sustained, but rapid, as is brought out by the simple facts contained in Table I. The amazing technology is well represented by the De Havilland Comet, which develops 460 h.p. with a weight ratio of 12 lb. per h.p. It therefore becomes interesting and perhaps useful to determine the extent to which metallurgy has contributed and is contributing.
Elevator Trimming Tabs
Authors: Lachmann G.V. , Stafford R.S.
Published: November 2014

MR. SERBY'S article on trimming and balance tabs gives a very concise theoretical explanation of the working of trimmer and balance tabs, and explains certain characteristics which have baffled most designers.
Aeronautical Progress 1930–1936
Authors: Relf E.F.
Published: November 2014

MUCH has been said earlier concerning the scale effect on drag. A few words must be added on the scale effect on lift near the stall, for it is here that ordinary small‐scale wind tunnel tests may be very misleading. The curves of Fig. 9 show the maximum lift coefficient of two wing sections plotted against Reynolds number, and the difference of behaviour is at once apparent.
Ducted Radiators
Authors: Meredith F.W.
Published: November 2014

THE drag of a cooling system may conveniently be divided into three categories:
A Classic Textbook
Authors: Southwell R.V.
Published: November 2014

WITHIN the limits set by practical considerations, stresses in engineering materials entail almost exactly proportionate strains. But in bodies of elongated shape, such as rods or thin sheets, displacements are not necessarily proportionate to the strains of which they are the integrated result, and hence, for such bodies, Hooke's law may hold in respect of some types of displacement but not of others. Applying end thrust to a long straight rod (or strut), and measuring the consequent approach of the ends, we find that this increases faster than in proportion to the thrust; under a load which would have been quite safe applied as tension, the strut bows largely and ceases to have value as a compression member.
Thin Sections in Torsion
Authors: Goodey W.J.
Published: November 2014

WHEN a thin‐walled hollow cylinder is subjected to torsion, it is generally assumed that, if the length is great compared with the linear dimensions of the section, direct stresses—in the direction of the axis of the cylinder—are absent, and that the shear stress is everywhere proportional to the thickness. The shear stress q is then calculated from the familiar Batho formula:
Training Radio Operators
Authors: Crook W.E.
Published: November 2014

A PASSENGER or freight‐carrying aeroplane without wireless will come to be regarded in much the same light as a ship without steering gear, and that time is probably not far distant. Wireless is to‐day accepted as being equally essential in air and marine navigation.
The Art of Dynamometry
Authors: Muir N.S.
Published: November 2014

IT is sale to say that in no branch of applied science have the difficulties been greater or the process of development more rapid than in aeronautics. By far the largest factor in the triumph of the aeroplane has been the improved internal combustion engine, a class of prime mover which, generating a maximum of power for a minimum of weight from concentrated fuel, is to‐day such an outstanding engineering achievement as to arouse one's curiosity regarding its origin and development.
The Art of Dynamometry
Authors: Muir N.S.
Published: November 2014

ONE of the main problems of pressing importance in aeronautics concerns the variation of engine power with height. For many years now attempts have been made analytically to arrive at a reasonable law for this variation but disagreement between calculated and observed performances of aircraft based on the supposed power factors has still kept critical attention focussed on any possible solution of this important matter.
Micro‐Photographical Methods
Authors: Kufferath A.
Published: November 2014

THE old and time‐tried chemical methods of determination of the technological properties of materials have, during the last 15 or 20 years, been accompanied and perfected by physical methods, such as the X‐ray or Gamma‐ray methods (i.e. the so‐called macroscopic and microscopic methods of material testing). These new methods have been developed to such an extent that the modern manufacture of sensitive and complicated apparatuses, such as aeroplanes, seems practically impossible without these ingenious methods of “ physical analysis.” The microscopic methods of determination particularly have been developed to a high degree of perfection, due to an equally rapid development of microscopic apparatus and auxiliary materials which had become necessary when from being an exclusively scientific apparatus the microscope was transplanted into the industrial laboratories. Microscopic testing of materials in vertical and oblique illumination is an absolutely indispensable aid of all industrial laboratories of to‐day.
The Langley Field Conference
Authors: Klemin Alexander
Published: November 2014

THE National Advisory Committee for Aeronautics received this year so many requests for attendance at its Langley Field Conference that the visitors were divided into two groups and two demonstrations were given with a day intervening. It is a sign of general prosperity in American aviation that so many representatives of the industry, the universities and government departments were able to attend. Besides presenting in outline the results of much solid research work, the Committee was able to show two new and original pieces of research equipment, in the form of a free‐flight tunnel and a gust investigation tunnel. So much material was (as usual) presented to the visitors that considerations of space will only allow the most concise presentation in the present article.
The I.Ae.S. Annual Meeting
Authors: Klemin Alexander
Published: November 2014

SINCE its inception, but a few years ago, the Institute of the Aeronautical Sciences has grown remarkably in the size and distinction of its membership, and the technical value of the papers appearing in its journal is now thoroughly well established. Thanks in a large measure to the organizing ability of its Secretary, Lester D. Gardner, the annual meeting was a great success. For the first time in its brief history simultaneous sessions were held, a method which works out quite well in the specialized atmosphere of modern aeronautics. The great difficulty with the annual meetings of American societies is that they are so huge as to render intellectual assimilation problematical. But the geographic conditions of the United States make it impossible for members from different parts of the country to attend frequent meetings such as those of the Royal Aeronautical Society.
Wood as a Homogeneous Material
Authors: Kraemer Ing. O.
Published: November 2014

IN treating of the glueing of wood one must distinguish between the mere carpentering operation of glueing, in order to produce a strong and watertight joint with the greatest economy of material and weight, and glueing undertaken to improve and enhance the qualities of the wood. For the latter one employs the most modern technical equipment and methods.
Synthetic Rubber‐Substitutes
Authors: Garner T.L.
Published: November 2014

SOME time ago a series of tests were described in these columns on synthetic rubber‐like materials in certain oils, including one to DTD.44B specification. Since that time there has been much further development of these new materials and, in particular, a Buna type of synthetic rubber has become available in this country. These German products were not available for export until the latter part of 1937, and, in fact, prior to that time severe penalties were imposed to prevent even samples being surreptitiously taken out of the country. Only one type is available up to the present, a modified Buna N, called in this country Perbunan, but this is the type most suitable for use in oil and solvent resisting rubbers.
Mechanical Tuning of Carburettors
Authors: Twelvetrees W.W.
Published: November 2014

THE problem of tuning and adjusting carburettors can well be remembered as a legacy from the earliest internal combustion engines and one which has hardly become simplified with the rapid development and improvement that aero‐engines have undergone in recent years. Although, to‐day, it is necessary to make but few individual adjustments in carburettors to suit the characteristics of particular engines, it is still essential in many instances to check every detail of carburettor functioning during engine bench tests. This creates difficulties, particularly when it is required to replace a carburettor on an otherwise serviceable engine. To subject the engine to complicated tests is obviously undesirable if satisfactory alternative means are available for checking the functioning of the carburettor as an interchangeable unit.
The Swelling of Wood
Authors: de Bruyne N.A.
Published: November 2014

WOOD though in many ways an attractive structural material has the disadvantage of being water absorbent. In itself this characteristic would be of minor significance were it not for the fact that it is accompanied by considerable swelling at right angles to the axes of the wood fibres. Great interest is being shown at the present time in the possibility of reducing this swelling by the use of synthetic resins. In this article the possibility of preventing swelling by such means is discussed and it is concluded that complete immunity from swelling could only be attained at the expense of the strength of the wood. The article gives an original analysis which enables the magnitude of swelling to be predicted and the expression derived is shown to be in agreement with experiment.
The Development of Liquid Cooling
Authors: Twelvetrees W.N.
Published: November 2014

FOR many years the basic design and construction of aircraft has been closely linked with the cooling system employed for the power plant which it is desired to utilise and as a general rule machines have been produced specifically for either liquid‐ or air‐cooled engines. Conversions of liquid‐cooled engined machines to suit an air‐cooled installation and vice versa have been successfully carried out in the past and to‐day there is a tendency for twin‐engined military aircraft to be constructed so that alternative installations may be employed, but the complications necessitated by such a practice provide good reason for producing the airframe to suit one particular engine. The general recognition of this policy has served to emphasise the importance of deciding the type of engine most suitable for the purpose for which the machine is required and has possibly lent weight to the claims submitted by various engine manufacturers. The merits of one variety of engine as opposed to the other is a subject which has from time to time received much attention, but, as the object of this article is to trace the development of liquid‐cooling systems, a brief outline of what is considered parallel advancement in air‐cooled practice may be of interest.
An Elementary Study of the Spin
Authors: Crowe J.H.
Published: November 2014

The rolling inertia moment can be obtained by substitution of liquation (1) in liquation (9). Thus:
The Design of Aeroplane Ducts
Authors: Patterson G.N.
Published: November 2014

AN interesting feature of modern aeroplane design is the growing use of duct systems. The low drag and heat regeneration obtainable from a cooling duct is now an accomplished fact. Ventilation systems for cabin aircraft have been introduced. In the future we may see duct systems used in connexion with the control of the boundary layer. As aeroplane design is improved, new applications of duct systems continue to appear.
Rotary‐Wing Aircraft
Authors: Bennett J.A.J.
Published: November 2014

THE conception of the rotating wing for the sustentation of aircraft has been known for the past few centuries (ref. 1), but not until recently has practical success been achieved. Modern developments are due principally to Juan do la Cierva (1895–1936), whose rotaplane, or “autogiro,” was the first successful aircraft with rotating wings. Although the patent literature on the subject is extensive, relatively little attention has been devoted to the underlying physical principles, a discussion of which will be given in the following pages.
Rotary‐Wing‐Aircraft Conference
Authors: Klemin Alexander
Published: November 2014

THE second annual Rotating‐Wing Aircraft Meeting was again held under the auspices of the Philadelphia Chapter of the Institute of the Aeronautical Sciences. The sessions were of considerable interest and were well attended. Many of the leading American aeroplane designers were present, including Grover Loening, Igor Sikorsky, and T. P. Wright.
Longitudinal Stability and Control
Authors: Gates S.B.
Published: November 2014

IN these notes I have attempted to describe the main features of longitudinal stability and control in the simplest possible terms, omitting the mathematical apparatus which makes this subject so formidable to those who are not constantly using it. Designers are certainly justified in complaining that most analyses of this subject contain, so to speak, so much XYZ that the ABC of the matter (if indeed there is one) is successfully hidden from them. In making a drastic attempt to return to ABC it must be realised that such a statement can be neither strictly accurate nor complete. Something will be gained, however, if it helps some designers to be clearer about what they are supposed to be doing in this part of their task, and why. The XYZ of the subject is, of course, indispensable to the working out of any particular problem of design A classified list of some useful recent British reports will be found in the Appendix.
Choosing a Carburettor
Authors: Ramsay D.
Published: November 2014

THE choice of a carburettor to suit a particular aero engine lies firstly in the choice of a make and type, then in the determination of the correct size. The choice of make (assuming a suitable type and range of sizes is available) is governed by a purely qualitative consideration of the properties of each type available and by consideration of the production facilities. The decision can, therefore, only be made after careful study and full understanding of the functional principles of each type, and weighing these up with the advantages claimed by the maker in each case. Points to be considered in the decision as to make and type are these:
Pressure Cabins and Temperature
Authors: Kittelsen H.M.J.
Published: November 2014

THE following article is intended us a discussion of the methods by which the cabin and wall temperatures can be investigated and the consequent deductions made for any pressure cabin aircraft generally.
Dynamic Balancing of Airscrews
Authors: Beebe Murray C.
Published: November 2014

The necessity for refinement of airscrew balance in order to eliminate destructive vibration from this source is due largely to the continuously improving standards of passenger comfort of modern aeroplanes and to the operator's desire to extend the normal service life of the power plant and its accessories as well as that of the aeroplane structure. Power plant vibration already has been reduced to a degree where, in standard aeroplanes, there is no longer danger of major structural failure due to vibration originating from this source. Efforts to refine further the balance of engines and airscrews are directed mainly at increasing passenger comfort and extending the service life of aeroplane equipment.
Torsion in Box Beams
Authors: Payne J.H.
Published: November 2014

THE effect of axial constraint on box beams of approximately rectangular section, subject to torsion, is of interest to the aircraft designer in connexion with the stressing of two‐spar skin‐covered wings. The stresses due to torsion in a uniform box with one end built‐in have been investigated by D. Williams, both by rigid methods and using the ordinary “engineer's” theory of bending. Three simple types of loading are considered:—
Minimum Induced Drag
Authors: Lockwood Taylor J.
Published: November 2014

IT is fairly well known that for any given wing arrangement—monoplane, biplane, monoplane with end‐plates corresponding with an increasingly popular type of tail unit, etc.—there is a definite lift distribution associated with the minimum value of induced drag of which a particular span is capable. The theory giving the appropriate lift distribution and, what is perhaps of more general practical interest, the resulting induced drag coefficient, is perhaps not so well known and while numerical results for arrangements in common use have been published, novel arrangements require a knowledge of the underlying theory for their evaluation, and this is in any case useful as giving a clear grasp and understanding of the problem.
Air‐line Engineering Management
Authors: Lusty Ivor
Published: November 2014

THE section whose efficiency should be least affected by the requirements of over‐suitability is the well‐established factory for the repair and overhaul of replaceable units, and this consideration adds much weight to arguments expressing the desirability of such unit parts for aircraft. The losses due to over‐suitability in this work can be considerably reduced by budgetary control, good planning and adequate spares, and at the same time the losses in other departments due to over‐suitability within themselves may be reduced by the reduction of the work required from them, and by far the most productive efforts to this end are those directed to the pursuance of the practices of absolute interchangeability of units. There is at the present time a movement towards this ideal, but the movement is slow and much remains to be done. In specifications and aircraft designs this ideal should be sought, and it will not be reached until every unit subject to wear and tear is a quickly detachable, easily replaceable unit, and absolute interchangeability is not achieved until the carrying out of such a replacement entails no more work on the aircraft than is required by the simple detachment and replacement of the unit.
The Lateral Stability of Aeroplanes
Authors: Price H.L.
Published: November 2014

SYMMETRIC AND ANTI‐SYMMETRIC WING LOADING DISTRIBUTIONS IT is proposed to work out the span loading distribution and lift and drag coefficients of an unstalled wing in symmetric flight, together with the wing rolling and yawing derivatives for rolling and yawing flight. The only data assumed are a knowledge of the geometry of the wing and of the slope of the lift‐incidence curve of any section of the wing when referred to infinite aspect ratio.
Vibrations in Aircraft
Authors: Manley R.G.
Published: November 2014

THE practical importance of preventing large vibrations in aircraft results from the two main effects of vibration, discomfort and danger. The discomfort aspect should not be disregarded, or dismissed as unimportant in comparison with the danger aspect. Both in military and in civil machines, discomfort from any cause is to be avoided if at all possible, as it can very seriously impair the operational efficiency of the air‐crew and lessen the attractiveness of flying as a means of transport. The provision of an adequate margin of safety is, however, essential, and this aspect is therefore of more immediate interest and importance to the engineer.
A Master Thrust‐Curve for Airscrews
Authors: Naylor V.D.
Published: November 2014

THOSE engaged on airscrew work are constantly making use of the tables of experimental values of kT and kQ for different values of J given in R.M. 1673. In using these tables it is usually necessary to extrapolate. It is the object of this article to show that, where we have strict grounds for comparison, we can construct a single thrust curve, which covers a wide range of pitch and conditions of working, and so obviate the need for extrapolation. The curve found covers the range of pitch p/p=0 to 1 and the working range below stall.
Administrative Engineering in the U.S.A.
Authors: Tiranti D. , Whipple G.A.
Published: November 2014

FOR some time past there has been in current use in the United States, the term “Industrial Engineering”; a term which in England is used but seldom, and with many varying interpretations.
Wind‐Tunnel Wall Interference
Authors: Tidbury G.H.
Published: November 2014

AN attempt is made here to summarize the present state of the theory of wind tunnel wall interference in a form that will be of some value to those using wind tunnels. The type of wind tunnel work frequently carried out without a complete knowledge of the corrections is also mentioned as it is of interest to those asking for, and using, wind tunnel results. A list of the most useful published reports on the subject is given at the end of the article, it is, however, by no means a complete guide to the literature of the subject, much of which is contained in academic volumes not usually available to the engineer using a wind tunnel.
Pressure Air Cooling Technique
Authors: Lind Walker G.E.
Published: November 2014

THERE is already in existence a vast amount of detailed data appertaining to cooling systems, but there appears to be a serious lack of general works on the whole subject. This paper is an attempt to formulate a general picture of the whole operation of engine cooling, and to provide a complete skeleton on which the various detail works can be hung together.
The Standard Wiring System for Aircraft
Authors: Emsley F.
Published: November 2014

THE use of electricity on aircraft commenced with the essential need of an electric spark to ignite the fuel charge in engine cylinders just as in the case of other mechanically propelled vehicles. Where a coil was used and not a magneto, or a number of navigation or other lights were — required, it was necessary to provide a secondary storage battery for the purpose of supplying current for a limited duration. Fortunately for the “power supply” of those days, the duration was often curtailed by some other factor such as engine failure or low fuel load, if nothing worse happened to reduce the flying time.
Methods of Strength‐Testing Aeroplane Wings
Authors: Hotson A.W.
Published: November 2014

THE testing of an increasing number of wings of greatly varying size, design and construction has emphasized the need for careful consideration of the object of the test in relation to the design of the wing structure to ensure that the most suitable type of specimen is provided for test.
Bending Moments in a Circular Ring by the Column Analogy
Authors: Gittleman W.
Published: November 2014

THE purpose of this paper is to present a method of determining the bending moments in a circular ring which is both speedy and accurate, and is particularly useful when dealing with a complex loading system. A general method which can also be modified for application to rings of any shape and of varying section is first dealt with. The particular case of a circular ring of constant section is then considered, the method being such that the work may be done entirely by substitution in formula or by obtaining values from curves which are readily plotted.
Warming Aircraft Accumulators in Sub‐Zero Temperatures
Authors: Woodfield Flight‐Lieutenant P.R.
Published: November 2014

ENGINE starting at low temperatures is difficult for the following reasons: (a) A cold engine requires higher torque to start it and thus imposes a greater load on the accumulator. This is not so marked with ball or roller bearings.