bluuebunny/crossref_metadata_2025 huggingface dataset:
Pressure Calculations for Oil Engine Fuel-Injection Systems
Authors: Giffen E. , Rowe A. W.
Published: October 2007

The paper gives details of a method of calculation for use in determining the pressure variations in the normal fuel-injection system. This method, besides dealing with the transmission of pressure impulses from one end of the pipe to the other, includes those modifying conditions present in an actual system, namely the capacity effects at the pump and at the nozzle, the action of the pump delivery valve, and the varying conditions in the spring-loaded injection valve.

The results of a calculation on a typical injection system have been incorporated in the paper. A diagram of nozzle pressure, obtained experimentally from the same system, is also included for comparison with the results of the calculation. This experimental diagram agrees so well with the calculated results that the treatment described may be regarded as giving a very close approximation to the actual conditions in the injection system.
Mechanical Engineering Problems in Marine Transport
Authors: Freeman Sterry B.
Published: October 2007

This, and the following papers by Mr. Stanier, Mr. Ottaway, and Mr. Gouge, were to have been read at the Joint Meeting of the Institution with the American Society of Mechanical Engineers in New York, which was cancelled owing to the outbreak of war.

The problems of mechanical engineering in marine transport are concerned with the steam engine and, in recent years only, with the oil engine. The problems vary from one type of service to another and the relative merits and cost of the various types of machinery available are compared. It is necessary for the engineer to satisfy the requirements of the shipowners and the surveyors in the most economic manner. The drawbacks and advantages of the two fuels, oil and coal, are contrasted and their effects assessed. The problems concerned with turbines, boilers, and oil engines are summarized. Electric transmission of power and mechanical gearing are reviewed, and the paper concludes by considering large handling plant and stating the position of the mechanical engineer with respect to problems of marine transport.
Problems of the Highway User in the United States
Authors: Horner Frederick C.
Published: October 2007

The present-day highway problem is made up of many elements, namely, cost of construction, ability of highway users to pay for highways as they are built or during their life expectancy, the kind of taxes providing revenue to pay for highways, types of roads required, competition between transportation systems, and kindred matters. No single solution exists for all of these. The author analyses comprehensively each of the elements of this nation-wide problem and suggests practical approaches to their solution. Of all the factors making up this problem that of cost is probably dominant. How the costs are to be met is the crux of the situation as it now stands, with the ever-expanding highway needs pressing for action. It is the author's view that a recent report of the Federal Works Agency, Public Roads Administration on the general question of “Toll Roads and Free Roads” offers the soundest long-range plan for national highway development yet advanced. A comprehensive analysis of this report has been included in an Appendix to the paper.
The Circulation of Water and Steam in Water-Tube Boilers, and the Rational Simplification of Boiler Design
Authors: Lewis W. Yorath , Robertson Struan A.
Published: October 2007

The authors stress the need for a sound theory of circulation in water-tube boilers, to enable weight and space to be saved and efficiency and reliability to be increased. They establish, as a standard of excellence with which other boilers may be compared, a simple boiler consisting of a single drum and a single U-tube.

The paper consists of three parts. Part I describes the nature of the change from water to steam; in part II the flow in the simple U-tube boiler is calculated; and in part III the features of various departures from the standard U-tube, met with in practice, are discussed.

An improved type of tube, approaching very nearly to the standard U-tube, is evolved, allowing much simplification of boiler design, with the advantages of excellent circulation, high gas speeds, and higher heat transmission rates. Other rational simplifications and improvements are also rendered possible, which enable substantial reductions to be made in the cost of manufacturing, installing, and maintaining boilers of any pressure and capacity, for any service, ashore or afloat.

The MS. of this paper was received at the Institution on 10th November 1938. The paper was presented for discussion at an Extra General Meeting of the Institution on 1st March 1940.
A Criterion for Knock in Petrol Engines
Authors: Plumb R. C. , Egerton A. C. G.
Published: October 2007

The problem was to correlate the tendency of a fuel to knock in a petrol engine, with the physical conditions in the cylinder which cause the knock, and with its ignition qualities in a bomb. The method of approach was to find a function of the physical conditions, the attainment of a critical value of which, during the stroke, is a criterion of knock. Theories of the mechanism of knock are reviewed, and suggest a rational form for this criterion. Engine tests of fuels were made at incipient and heavier knock under a variety of engine conditions, and indicator diagrams were obtained by an oscillograph indicator. Assumptions, based on the rational form, were made for the form of the criterion; and by analysis of the diagrams, etc., a reasonably satisfactory form was selected. Substantially the same critical value was then obtained for incipient knock under all running conditions, including change of compression ratio. The possible application to fuel rating is discussed. The ignition experiments indicated that the same critical value of the same function is a criterion of auto-ignition in a bomb, and they suggested a similarity between the mechanism of knock in an engine and auto-ignition in a bomb.
Fretting Corrosion and Fatigue Strength: Brief Results of Preliminary Experiments
Authors: Warlow-Davies E. J.
Published: October 2007

Fretting corrosion, the conditions under which it occurs, and the possibility of its effect on fatigue strength, are discussed. Fretting corrosion always appears in regions of unknown stress concentration, so that an accurate estimate of the weakening effect due to it cannot be made from combined fretting and fatigue tests. It is suggested that fatigue tests of previously fretted test pieces, analogous to determinations of the percentage loss of fatigue strength by prior stressless chemical corrosion, would be useful. Apparatus for making such tests is described, and preliminary results for a medium-carbon steel and for a nickel-chromium-molybdenum alloy stéel are given. The losses of fatigue strength after fairly severe fretting were 13 per cent and 18 per cent respectively. Although these are not necessarily maximum values, reductions of this order are regarded as justifying further investigation, and the suitability of the apparatus and methods used is considered.
III. Report on Martensitic Cast Irons
Authors: Pearce J. G.
Published: October 2007

The resistance to wear, erosion, and abrasion which is characteristic of martensitic cast irons has brought about their employment in a number of engineering applications. Martensitic cast irons may be produced by heat treatment of an ordinary engineering pearlitic iron; or they may be specially produced and so treated that either of two varieties can be obtained. In one such variety the eutectic filling surrounding the primary grains is allowed to solidify white (cementitic), and in the other it is allowed to solidify grey (graphitic). There are thus two main classes of the martensitic cast irons which are specially made as such; they may be respectively described as “white” and “grey” in character, the former being the harder of the two. The “grey” variety can be made martensitic in the condition as cast, or alternatively a martensitic structure can be produced in it by suitable heat treatment.
Some Problems Connected with Steam Turbine Governing
Authors: Higgs-Walker G. W.
Published: October 2007

The recent growth in the size of steam turbines has made desirable the use of governing systems using two or more relays working in series to operate the governor valves. The rise in initial steam pressures and the increase in the number of turbine cylinders which has accompanied this growth has increased the relative energy of the steam entrained in the steam chests, cylinders, and interconnecting piping so that this entrained steam has become a most important factor in problems concerned with the stability of governing and with the maximum temporary speed rise when load is suddenly removed.

The present investigation has been made to determine the effect of the number of relays and of the entrained steam energy on governing stability and on temporary speed rise. The problems have had, to some extent, to be treated separately as the inclusion of governor inertia, multiple relays, and entrained steam lead to stability criteria of too great complexity to be generally useful.
Proneness to Damage of Plant through Enemy Action
Authors: Gutteridge Hal
Published: October 2007

The aim of the paper is to draw attention to the facts which underlie the rapid approximate estimation of damage to plant through enemy action.

Different items of plant will be affected to a greater or lesser extent depending upon their type and the conditions to which they have been exposed. Thus, a smith's anvil, at the one extreme, would be but slightly damaged by blast, fire, collapse of the building, falling debris, or flooding, if a direct hit or persistent fire was excluded. At the other extreme, delicate electrical apparatus would suffer severely if exposed to any of these conditions. In the case of the anvil the “damage proneness number” (d.p.n.) is likely to be between the limits of 0 and 5, whilst that of the latter may be between 80 and 100 in “average” cases where a direct hit or persistent fire did not take place.

Thus all plant can be classified and given probable limits beforehand of the extent of damage, and it would remain for the trained observer to fix the damage proneness number which in exceptional cases might be outside the average limits.

Expressed as a percentage of the value of the item, the damage proneness number would indicate the amount of the loss involved; the sum of the amounts of the individual losses would give the total approximate loss.

The extent of the damage is affected also by the protection given by the building, the position of the item within the building, and by the type of bomb and its point of impact in relation to the item.
A Review of Recent Progress in Heat Transfer
Authors: Lander C. H.
Published: October 2007

The state of knowledge of heat transfer in relation to mechanical engineering problems was summarized by Professor Dalby in a paper before the Institution in 1909. The present paper discusses the growth of knowledge during the past thirty years, and the ever-expanding fields of application. Complete rationalization is still not possible, but dimensional methods similar to those used in ship and aircraft design are being applied more and more generally to heat transfer problems. By their aid the practical range of any set of data may be greatly widened. For example, experiments made under pressure on surfaces only a few inches high may be used to deduce the heat transfer for surfaces several feet high at atmospheric pressure; or experiments made in gases may be used to predict the heat transfer in liquids. Selected cases dealt with in the paper are: forced convection for banks of tubes and beds of broken solids, and the relation between heat transfer and friction; natural convection from vertical and horizontal surfaces and across fluid layers; heat transfer in the drop and film condensation of steam, and in film and nucleate boiling; evaporation and its relation to convection; emissive powers of surfaces for radiation; and radiation from non-luminous gases.
Caustic Embrittlement
Authors: Colbeck E. W. , Powell L. , Smith S. H.
Published: October 2007

The paper contains the results of experimental work on caustic embrittlement. The type of apparatus chosen was based on one used in recent American work carried out by Straub and Bradbury (1938). In this, the solution to be tested is contained in a hollow sealed tubular specimen, heated to any desired temperature in the steam boiler range, and subjected to a tensile load by means of a spring.

It has not been possible to reproduce the results claimed by Straub, but a number of examples of intergranular cracking have been produced. Some of these have been obtained when using dilute solutions containing amounts of NaOH and silicate such as would be found in boiler waters. There is evidence that embrittlement occurs more readily in poor-quality steel and under conditions of non-uniform stress distribution, but it has not been possible to reproduce results with any degree of certainty.

A few experiments with an entirely different type of specimen have been carried out; and in these, intergranular failures have also been produced.

The paper also contains a survey of the more important literature on caustic embrittlement published between 1935 and 1941.
The Soot Blower, with Special Reference to the Present Position of Power and Automatic Operation of Mechanical Blowers
Authors: Glinn R. J.
Published: October 2007

The nature and extent of the deposits which occur on the heating surface of a boiler unit are variable in the extreme. The method of firing and the rate of combustion are open to choice. The completeness of combustion can be controlled to some degree, but the quantity and chemical constituents of the ash can seldom be forecast, and may vary widely.

The form of fouling, and the effect on the different portions of the heating surface of the boiler unit, are examined.

Development of the application of soot blowers from 1919 is discussed, particularly the use of the single-nozzle blower. The design of the boiler to permit full use of the different types of soot blowers available is referred to, and mention is made of the effect on furnace walls, boiler tubes, and superheaters, economizer, and air heater surfaces. The future design and rating of boilers depend to a great extent on the development of the means of cleaning the heating surface. Reference is made to cleaning by water lancing and other means for special cases.

The importance of the availability of plant is emphasized, and essential features of power-operated mechanical soot blowers, with special reference to automatic operation, are outlined. The scope of use of the three main types of soot blowers is set out, as well as the essential features of their design. Points for consideration in the periods between individual soot blowing operations and the extent of each blowing, are enumerated, and in section (3) of Appendix I (p. 96) the types of automatic soot blowers on the market are briefly described; a general indication of the trend of modern design of blowers, both electrically and hydraulically operated, is also given.
Third Report of the Research Committee on High-Duty Cast Irons for General Engineering Purposes
Authors: Pearce J. G.
Published: October 2007

The Third Report was originally projected as the Second Report,† but the necessity of making use, under war conditions, of the most readily available indigenous ores, caused the Committee to concentrate immediate work on the influence of phosphorus upon mechanical properties. The Second Report has already dealt with the influence of this element on the properties of the plain cast irons, whilst the Addendum to the Second Report‡ covers the alloyed cast irons.

The Third Report contains in Part 1 further results on commercially made high-duty cast iron, i.e. those equivalent in properties to, or better than, grade 2 of British Standard Specification No. 786 (1938), and in Part 2 the results of the remainder of the experimental programme concerning alloy cast irons, showing the influence of additions of nickel, copper, chromium, and molybdenum, both severally and in various combinations, on certain selected compositions. Both parts of this Report refer to the machinable engineering cast irons, having a pearlitic structure with normal flake graphite, covered by class 11 of the classification§ given in the Reports on Special-Duty Cast Irons. The more recently developed so-called acicular cast irons, showing excellent mechanical properties, do not fall within this category, and are being made the subject of experimental work.
A Survey of Modern Centrifugal Pump Practice for Oilfield and Oil Refinery Services
Authors: Tetlow N.
Published: October 2007

During the last thirty years there has been a manifold increase in the demand for centrifugal pumps for oilfield and oil refinery service, an increase in which British engineers have played a worthy part. With traditional British reticence little has been said of the achievements of British oil companies and British pump manufacturers in this field of activity, and the author has written this paper with the object of correcting the omission. In the field of oil transportation over long distances, for instance, the influence of British practice is to be seen in many oilfields throughout the world.

Within the refinery considerable strides have been made, particularly in solving the difficult problem of handling unstable hydrocarbon liquids under high suction pressures. Hot oil pump practice is now more or less established, and in this development the greater share of credit is due to American pump manufacturers. These developments are dealt with at some length in the appropriate section of the paper.

Another point which calls for comment here is the introduction of a new term, for the characteristic of flow into the impeller eye, which is used in section 3 of the paper. When dealing with hydrocarbon liquids under saturation pressure and temperature conditions, the so-called “suction performance” of a centrifugal pump becomes extremely important. As a description of this most important characteristic of a pump the use of the phrase “suction performance” is misleading, and it has led to much confusion of thought. An attempt has been made to reduce the possibility of further confusion by coining a new phrase based on the analogy of similar characteristics encountered in electrical engineering. Throughout the paper, therefore, the pump characteristic relating to flow into the impeller eye has been described as the characteristic of “flow inductance”.

The paper would not be complete without an attempt to assess the future trend. There will probably be a much greater tendency towards electrification of main-line pumping plant. A further increase in operating temperatures and pressures will, no doubt, lead to many fundamental changes in the design of pumping plant for use inside the refinery. As an example, it is suggested that for some difficult duties it may be necessary to adopt pump designs in which stuffing boxes are avoided altogether. Finally, it is probable that refinery technologists will tend more and more to adopt chemical processes and chemical engineering practice, so introducing new problems for the pump designer.
The Calculation of Roll Pressure in Hot and Cold Flat Rolling
Authors: Orowan E.
Published: October 2007

A numerical or graphical method is given for computing, in strip or plate rolling, the distribution of roll pressure over the arc of contact and the quantities derived from this (e.g. the vertical roll force, the torque, and the power consumption). The method avoids all mathematical approximations previously used in the theoretical treatment of rolling, and permits any given variation of the yield stress and of the coefficient of friction along the arc of contact to be taken into account. It can be used, therefore, in both hot and cold rolling, provided that the basic physical quantities (yield stress and coefficient of friction) are known.

The usual assumption that the deformation could be regarded as a locally homogeneous compression has not been made, and the inhomogeneity of stress distribution has been taken into account approximately by using results derived by Prandtl and Nádai from the Hencky treatment of two-dimensional plastic deformation.

It is found that the discrepancy between the roll pressure distribution curves calculated from the Kármán theory and those measured by Siebel and Lueg is due to the assumption in the theory that the frictional drag between the rolls and the rolled stock is equal to the product of the roll pressure and the coefficient of friction. If frictional effects are dominant, as in hot rolling, this product may easily exceed the yield stress in shear which is the natural upper limit to the frictional drag, and then static friction, instead of slipping, occurs. This has been taken into account in the present method, and the calculated curves of roll pressure distribution show good agreement with the curves measured by Siebel and Lueg.
Creep Properties of Steels Utilized in High-Pressure and High-Temperature Superheater and Steam Pipe Practice. Part I: Carbon Steels
Authors: Tapsell H. J.
Published: October 2007

This report deals with the creep properties of carbon steels used in superheater headers, superheater tubes, and steam pipes for service at temperatures up to about 480 deg. C. The object of the investigation was to obtain data for the estimation of the stress-temperature relationships for specific creep strains of 0·1–0·5 per cent to occur in 100,000 hours, and these have been obtained with sufficient precision to warrant their acceptance for practical purposes. Similar components in molybdenum steel are under investigation.
The Hydraulic Operation of Lathes for the Production of Shells
Authors: Philip W. Littlejohn
Published: October 2007

The paper is limited to the application of hydraulic power to lathes designed for shell making although, in the author's opinion, there is an immense field for the application of the same principles in other directions. Self-contained hydraulic machine tools have been dealt with by Mr. H. C. Town,† but in the system to be described all the machines are operated from a central hydraulic plant. Three complete installations on this principle have been established by the author, and the present paper contains an account of this work from the first experiments in 1915 until about four years ago.

The first plant was constructed in 1915 for the production of 3·29-inch shells, known as “18-pounders”, from the solid bar. The output was 2,000 shells per week of 135 hours, with girl operators working on three shifts. The second plant was put down in 1916–17 for an output of 500 9·2-inch howitzer shells per week of 135 hours, also with girls working on three shifts. The third plant is of recent design. It was started in 1938 for the production of 3·45-inch shells, known as “25-pounders”; and was laid out for an output of 1,000 shells per week of 47 hours. This plant included four types of hydraulic lathes which the author was engaged to design for the War Office.

Soon after the commencement of the last war in 1914 it became evident that shell production would have to be greatly increased, and engineering firms were pressed to take up shell manufacture. The author, on behalf of his firm, undertook to help in the movement, and he at once set about the construction of some simple machines for the job. These conformed on general lines to the practice of the period as regards design and operation. He soon realized, however, that drastic changes would have to be made if production was to reach the high level that circumstances demanded. Although quite familiar with hydraulic machinery of various types and of many applications in presses and certain types of heavy tools, he was not aware of any instance in which hydraulic power had been applied to the movements of a lathe. It appeared to him, nevertheless, that it would be possible to construct a very useful machine on these lines, and he accordingly started immediately to carry out experiments and to prepare designs.

It was considered essential that machines for the duty which the author had in mind should be much heavier and more rigid than the ordinary machines of the time, so that they should be free from vibration and “chatter” or spring with the heaviest possible cutting. The standard of rigidity aimed at was that which would permit a half-crown coin to remain balanced on edge on the moving saddle or turret while the tools were making the heaviest cuts. This object was achieved, and the demonstration was frequently made in the presence of those who came to see the lathes at work.
The Abnormality of Flame Gases
Authors: David W. T.
Published: October 2007

Hot gases formed as a result of combustion behave differently from normal hot gases of similar composition, and it is believed that a full appreciation of this fact would lead to the opening up of a wide field of profitable research.

Experiments are described in the paper which show that flame gases hold within them a long-lived latent energy. It has been found that the latent energy may amount to as much as, or even more than, 15 per cent of the heat of combustion; but it varies greatly with the conditions under which combustion takes place. These conditions have been investigated by means of explosion pressure and heat loss measurements, flame gas temperature measurements, and flame photography.

Experiments are also described which show that in virtue of the latent energy an abnormally large amount of dissociation may obtain in flame gases. On account of this, a platinum wire immersed in flame gases may attain a far higher temperature (some hundreds of degrees Centigrade higher) than a similar wire coated with quartz, and this cannot be accounted for in terms of the different emissivities of the surfaces. There seems little doubt that this phenomenon may have an important bearing upon such problems as the transmission of heat from flame gases and the selection of gas fire radiants.

Flame gases resulting from the combustion of weak hydrogen-air mixtures behave in a quite exceptional manner and a short account of some experiments with these gases is given in Appendix I, p. 243.
Static and Clinging Friction of Pivot Bearings
Authors: Hunter M. C.
Published: October 2007

The author points out the clear distinction which has to be drawn between kinetic and static friction, and describes the special apparatus used in the investigation carried out to determine the static friction of various combinations of metals, including stainless steel and duralumin, under several conditions of dry and viscous lubrication.

The paper stresses the effect of time, and gives data showing the rapid growth of the coefficient of friction during the first twenty-four hours at rest, and the subsequent increases over a period of five days.

A series of long-term tests of thirty, sixty, and ninety days, on a selected number of specimens, provides a direct comparison from which the relative merits of the various combinations of materials is drawn.

Evidence is provided suggesting advantages to be derived from the use of graphite as a preventative of clinging friction.

In conclusion, an explanation is put forward as to the possible causes responsible for the building up of friction with the passage of time.
Marking Methods and War Production
Authors: Throp Arnold
Published: October 2007

The paper begins with a citation of the regrettable lack of appreciation, amongst engineers generally, of marking as a production operation necessitating careful planning and tooling.

It continues with an appeal to conserve the sadly overstrained capacity of the marking device industry by observing the following points. First, different classes of marking should be separated according to their respective purposes, and unnecessary classes should be eliminated. Second, the design of marking devices should be left to those who have made it their especial study; and thus, by avoiding the many pitfalls of a technical nature which few draughtsmen have had an opportunity of considering, the inefficient utilization of highly skilled labour, the unduly heavy consumption of marking tools due to premature failures, and the production of poor quality work will be prevented. Third, the attention of designers of aircraft, ammunition, and the other components should be directed to a consideration of marking processes before specifying the positions and surfaces on which marking is to appear and the form it is to take. Finally, the paper illustrates the possibilities of marking awkwardly shaped components, the production of accurate scales, the endurance of marking dies, and the rates of output that can be achieved. Numerous photographs and diagrams of representative methods and equipment are included.
The Thermal Rating of Worm Gearboxes
Authors: Walker Harry
Published: October 2007

The paper deals with the factors affecting the temperature rise of totally enclosed self-lubricated gearboxes, with particular reference to worm gearboxes, and is based on observations obtained from a power circulating apparatus through worm gears which has provision for the accurate measurement of efficiency and temperature rise under variable load and speed.

The theory underlying the heating and cooling of gearboxes is discussed, for gears running under continuous load and also under a repeated cycle of intermittent load.

Temperature rise depends on the heat-dissipating capacity of the gearbox and the power losses within the box; heat-dissipating capacity is dealt with in relation to surface area of the box, speed of the gears, and artificial cooling by air fan; power losses are discussed under the headings of efficiency and oil drag losses. It is shown that gear speed and turbulence in the lubricant contribute considerably to heat-dissipating capacity, and that oil drag losses play an important part, particularly on large gears running at moderate or high speed. Cooling by air or other means is shown to result in an increase in power capacity (for a given allowable temperature rise) much more than in proportion to the increase in heat-dissipating capacity of the box, owing to a higher overall efficiency when transmitting heavier loads.

Results of worm gear efficiency tests carried out in the past on the Daimler-Lanchester testing machine at the National Physical Laboratory on the author's design of worm gear, which gave the highest efficiency of any published tests carried out on this machine, are reconsidered in the light of recent work and it is contended that the National Physical Laboratory machine gives efficiency figures which are in general higher than the true efficiency.
Temperature-Indicating Paints
Authors: Tyte L. C.
Published: October 2007

The requirements to be satisfied by temperature-indicating pigments are stated and the development of pigments to meet this specification is described. The extension to multiple transition paints and the development of binding materials and the composition of the paints are then discussed. Methods of application of the paints and the recording of results are considered. Factors influencing the temperature—colour change relations are then examined; they include ( a) the time effect, ( b) the effect of liquid films and gases, ( c) the effect of heat transfer by conduction and radiation, and ( d) redistribution of temperatures during cooling of the body. Consideration is given to the estimated accuracy of the temperature indicated. A review of uses in (i) Mechanical Engineering, (ii) Electrical Engineering, (iii) Chemical Engineering and Metallurgy, and (iv) Teaching, is made.
The First James Clayton Lecture: The Early History of the Whittle Jet Propulsion Gas Turbine
Authors: Whittle F.
Published: October 2007

“I do not endeavour either by triumphs of confutation or pleadings of antiquity, or assumption of authority, or even by the veil of obscurity, to invest these inventions of mine with any majesty …”. Francis Bacon.
Some Practical Applications of Rubber Dampers for the Suppression of Torsional Vibrations in Engine Systems
Authors: Zdanowich R. W. , Moyal J. E.
Published: October 2007

The method of rubber damper design outlined in this paper has been developed owing to the breakdown on a number of occasions of the two-mass system method hitherto widely used.

This new method, which is based on the study of the behaviour of the engine as a whole in conjunction with the damper, splits up the functioning of a damper into two parts, one conveniently called the detuning effect, and the other, the absorption effect. The first relies on the powerful tuning curve method, already described in the Proceedings, and the other is based on numerous painstaking trials and physical tests on rubber samples and on full-scale dampers.

The method outlined shows that there is no rigid relationship between the frequencies of the engine and damper, and that the free end of the engine crankshaft is not the only place where a successful damper can be fitted.

In addition to giving some particulars about physical and other properties of rubber, it also shows how to calculate the heat dissipated by dampers.

Practical support for the theory is provided by accounts of vibration trials on three widely different types of engines with dampers fitted to them. In all cases, comparison of calculated and experimental amplitudes is given. The good agreement between the two cannot escape attention and shows that the method outlined can be used with confidence.
Recent Research in Metal Machining
Authors: Galloway D. F.
Published: October 2007

Despite the introduction of comparatively new manufacturing processes such as powder metallurgy and plastics which are gradually assuming their true functions in industry, manipulation of metals by machining still occupies a place of major importance among methods of production and the efficiency with which machining operations are carried out continues to influence greatly the overall industrial efficiency of the country.

Research provides a means of greatly accelerating progress toward the goal of efficient metal machining, and recent developments in other fields of science and industry now present opportunities of research and development in metal machining, incomparably greater than have hitherto been known. The progress recently made in the field of surface finish measurement which, for the first time, makes possible a rational investigation of finish machining operations, is just one example of newly acquired knowledge which can now be applied in solving the complex problems of metal machining.
On the Resistance Coefficient–Reynolds Number Relationship for Fluid Flow through a Bed of Granular Material
Authors: Rose H. E.
Published: October 2007

The resistance coefficient–Reynolds number relationship for a bed of spherical particles, closely graded about a mean size, is considered and it is shown that this relationship correlates with that for a bed of non-spherical particles, provided a suitable allowance for particle shape is made.

It is shown that for very large or very small values of the Reynolds number the co-ordinates of the resistance coefficient–Reynolds number curve fall closely about a mean line but for the transition-range the points suffer considerable scatter—probably due to the indeterminate nature of the flow in the pore channels for this range of the Reynolds number.

Curves are given showing the frequency of occurrence of variations in the resistance coefficient, and an example of the practical application of these curves to a design problem is fully worked out.

Curves relating the resistance coefficient to the Reynolds number for beds of particles of various degrees of angularity are put forward tentatively, these relationships being, as yet, not completely established.
Creep Properties of Steels Utilized in High-pressure and High-temperature Superheater and Steam Pipe Practice. Part II: 0·5 per cent Molybdenum Steels
Authors: Tapsell H. J. , Ridley R. W.
Published: October 2007

This report deals with the creep properties of carbon-molybdenum steels in the form of a superheater header, superheater tube, and steam pipe manufactured for service at temperatures above about 450 deg. C. (842 deg. F.). The investigation was carried out in a similar manner to that described in Part I (Proceedings, 1944, vol. 151, p. 54) which dealt with carbon steels and, as in the former case, the object was to obtain data for the estimation of the stress-temperature relationships for from 0·1 to 0·5 per cent creep in various periods up to 100,000 hours. It is considered that the data provide a satisfactory basis for design.
Induction Ramming Effects in Single-Cylinder Four-Stroke Engines
Authors: Kastner L. J.
Published: October 2007

The paper describes a series of experiments carried out to determine how the fluctuations of pressure, which occur in the induction pipes of four-stroke engines, may be best employed to improve the charging of the engine cylinder. Two single-cylinder engines were used during the tests, the first being a medium-sized water-cooled unit running at speeds between 1,000 and 2,000 r.p.m., the second a smaller air-cooled engine capable of higher rotational speeds. The effects of changes in diameter and length of induction pipe were explored with both engines, the valve timing remaining fixed; and, using the water-cooled unit, extensive trials were carried out at three standard engine speeds to find what valve timing gave maximum air consumption for each of a number of induction pipe lengths. Finally, the influence of several sizes of carburettor Venturi tubes in damping out the pressure fluctuations and reducing the ramming effect was investigated. Information is given, based on the results of the experiments, enabling a suitable length and diameter of induction ramming pipe to be chosen for engines running at any constant speed, as well as for those covering a wide range of speeds.
Quantitative Analysis of Single- and Multiple-Capacity Plants
Authors: Kaufmann Paul G.
Published: October 2007

In order to predict the performance of an automatic regulator, it is necessary to know the characteristic of the plant to which the regulator will be applied. A plant may consist of one or more capacities separated by resistances, and is characterized by its plant constants.

The behaviour of an uncontrolled plant can be described by a non-homogeneous differential equation of the same order as the number of capacities forming the plant. The independent variable in this equation is the time; the dependent variable is the deviation of the plant from equilibrium; and the disturbance function is a function of the disturbance applied to the plant. This disturbance function and the resulting deviation will, in general, be different for disturbances created at the supply and discharge side of the plant.

The use of hydraulic plants as models demonstrates clearly the physical meaning of the terms involved which can easily be translated into terms of thermal, flow, electrical, or other problems. Assuming a viscous medium with linear resistance to flow, linear differential equations are obtained and the deviations from equilibrium due to different forms of disturbances are examined for single- and multiple-capacity plants. Inversely, it is demonstrated how the plant constants can be determined from observed deviations when definite disturbances are applied to the plant.

It is also shown why, for the control of multiple-capacity plants, it may be of advantage to use regulators that respond not only to the deviation from equilibrium but also to the speed and the higher derivatives of the deviation. The relative merits of placing the regulator at the discharge or supply end of the plant are also discussed.

Finally, it is indicated how the equations of a regulator and of the plant can be combined to describe the behaviour of the regulating system and the interaction of regulator and plant, and how its stability criteria can be established.
Boiler Draught Production by Means of the Jet Air-Pump
Authors: Benson S. F.
Published: October 2007

One of the most extensive applications of the jet air-pump in industry is its employment for the production of draught for the furnaces of Lancashire type boilers.

The purpose of the work described in the paper was to investigate the conditions under which the requisite quantity of air can be supplied to the furnace of a boiler with minimum consumption of steam, and to examine the performance of a number of well-known and widely used furnace bars designed for this purpose.

Two well-defined stages can be discerned in the process: (1) the induction of air by the jet; and (2) the transfer and distribution of the air to the furnace grids and the fuel bed. These two stages, which to some extent are interdependent, nevertheless lend themselves to individual treatment, a method which was followed in this work.

With the induction process, guidance can be obtained from a theoretical analysis of the problem; and such an analysis was in fact used. For the transfer and distribution of the air to the grids and fuel bed, experiment alone can provide the required information.

The question of the “efficiency” of the system in the normally accepted sense of the term is discussed, and is shown to be irrelevant to this method of operation. Some such term as “coefficient of performance” is more useful, and better suited for the purpose.
Industrial Fans: Their Practical Evaluated Rating, Performance, and Control
Authors: Kice M. S.
Published: October 2007

The purpose of the paper is to draw attention to the situation which obtains when fan equipment forms part of the plant used to manufacture a product.

Considerable detail is given in support of the points advanced, which deal mainly with the economics of production and include fan development, rating, design, application and control. Particular attention is devoted to the practical side in order to show how to obtain maximum financial profit from investment in fan equipment.

As the theory of fan characteristics has, mainly, been evident in the literature on the subject, such theory has been avoided, excepting in connexion with the classic argument about the parallel operation of forward-curved bladed fans, concerning which, four premises have been cited in an attempt to inspire a mathematically qualified reader to develop a theory agreeing with observed phenomena—a theory which has not yet been produced.

In the section of the paper dealing with the control of fans, the economic aspect is again stressed, particularly in connexion with the relationship between overall boiler efficiency and the method of controlling boiler house fans, the problem being resolved into terms of control of the carbon dioxide content of the flue gases.
Cutting Tools Research: Report of Subcommittee on Carbide Tools: The Mechanism of Tool Vibration in the Cutting of Steel
Authors: Arnold R. N.
Published: October 2007

The report deals with some fundamental investigations of vibration in cutting tools. It is shown that this phenomenon may be the result of both self-induced and forced vibration. The former is a function of the cutting properties of the metal and the sharpness of the tool, while the latter depends on the interference of the tool with the surface cut during previous revolutions. Certain limitations of speed, tool frequency, and tool sharpness exist, vibration being rarely observed at low cutting speeds, at high tool frequencies, or with a freshly lapped tool. The amplitude of vibration appears to be independent of the depth of cut and seems to be limited to a value slightly in excess of that which makes the maximum vibrational velocity at the tool point equal to the speed of the work. It is governed to some extent, however, by the internal damping characteristics of the tool shank.

The self-inductive influence originates from the decrease in the cutting force which occurs as speed is increased, and becomes more powerful as the wear of the tool progresses. Failure of carbide tools under vibratory cutting conditions occurs in the form of a fatigue crack which spreads inwards parallel to the top face of the tool. Photographs and profile records are given of surfaces cut under various conditions of vibration, together with a theoretical analysis of the manner in which the surfaces are formed. With small feeds, forced vibration occurs and phasing normally results. This is demonstrated by the resulting patterns on the surface, which show an orderly arrangement of the waves. A few practical examples are described.
Some Notes on the “Merchant Navy” Class Locomotives of the Southern Railway
Authors: Bulleid O. V. S.
Published: October 2007

The operating requirements in respect of weights of trains and speeds determined the main dimensions of these new locomotives, and the paper refers to the limitations on the development of powerful locomotives imposed by the loading gauge and weight restrictions.

The Merchant Navy class locomotives embody many innovations in British locomotive practice, and the reasons for these changes from orthodox practice are fully explained, and the way in which the changes were carried out described.

Some difficulties were naturally experienced in service as a result of these departures, and they are fully related, together with the modifications which successfully overcame them. Some of the improved results obtained as a result of the innovations are reported.
The Loop Scavenge Diesel Engine
Authors: Carter H. Desmond
Published: October 2007

The main theme of this paper concerns loop scavenge two-cycle engines as a type, but most of the examples refer to trunk-piston engines of powers up to 2,000 b.h.p. The characteristics of such engines are enumerated and a comparison is made with other established types of engines—both two-cycle and four-cycle—in marine, stationary and locomotive applications. Details of performance are given.

Exhausting, scavenging and charging processes of loop scavenge two-cycle engines are dealt with and in particular a new method of filling the engine cylinder (“exhaust pulse pressure charging”) is described. There then follow data regarding scavenge efficiency and design of ports.
The Evolution of a Tank Transmission
Authors: Merritt H. E.
Published: October 2007

This paper describes, substantially in chronological order, the stages of an investigation into the theory and design of steering mechanisms for armoured fighting vehicles.

The first step was an inquiry, partly by simple experiment and partly by analysis, into the mechanics of a skidding track; the application of the conclusions to a complete vehicle led to unexpected results in regard to the forces and powers involved, and explained the unsatisfactory behaviour of earlier transmissions designed on a purely empirical basis. This was followed by review and analysis (although not necessarily in the classified order given in the paper) of existing or known types of mechanisms applicable to tank steering. An experimental mechanism of the coupled-differential type was then constructed in order to verify the conclusions drawn. Before it could be completed, the necessity arose for a rapid increase in the production of tanks beyond the limit of size and weight at which existing steering mechanisms could be expected to be satisfactory, at a time when limited production resources put a premium upon economical design.

There were grounds for believing that the triple-differential mechanism, devised at that time, would combine the desired technical performance with comparative economy in production; this expectation was confirmed, although only after a period (outside that covered by the paper) of development of detail reliability. The problem of testing tank transmissions was also studied and the plant finally devised and constructed for this purpose has a number of interesting technical features. The technical elaboration of the internal mechanics of tank transmissions, accumulated in the course of the study, has been omitted from the paper as lacking in general interest. It reached its maximum of complexity in the case of the test plant and is left as an exercise for the student. The problem of the effect of centrifugal force still awaits a complete solution.