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In order to exploit the well-known advantages of gas bearings, it is necessary to be able to optimize each individual design. The non-linearity of the basic Reynolds equation makes this difficult. The application of numerical methods is tedious and expensive. Analytical solution can be obtained by making certain basic assumptions and linearizing the equation. An interesting way to linearize the Reynolds equation is the ph solution found by Ausman on his work on plain journal bearings. An extension of this method has been done by Pitts, for tilting pad bearings. The aim of this paper is to compare the analytical solution with the experimental results, and so ascertain the validity of the hypothesis. During the experiments the influence on the shape and thickness of the gas film of the parameters (load, speed, bearing size, clearance and pivot location) has been studied. It is shown how a choice of pad may be made to fulfil a certain requirement.

Optical microscopy, scanning electron microscopy and electron probe microanalyser techniques have been used to study the pickup of abrasive particles in annealed aluminium during abrasion on silicon carbide abrasive papers. Neither optical nor scanning electron microscopy adequately characterises the surface with respect to grit pickup. However, the electron probe microanalyser can be used to give semi-quantitative assessment of abrasive pickup, despite its limitations when examining rough surfaces. The present results show that the pickup of silicon carbide particles increases with increase in track length, increase in applied load and decrease in grit size; it is also markedly influenced by lubrication.

The usual methods of testing alternating-current high-voltage paper-insulated cables are based upon the ability of the insulating material to withstand excessive potentials in order to determine its condition. Accordingly, these methods are not suitable for routine tests imposed for the purpose of determining the degree of deterioration existing in any particular cable. In an effort to develop a routine test, which will serve to detect an impending fault, use has been made of the kenotron as the source of high-potential direct-current. By means of it a large volume of data has been secured concerning the input-current, for a cable, as a function of time after complete electrification at a constant high potential. These data when plotted, as curves, show by their shape the condition of the cable insulation. Curves showing a sharp decrease in the magnitude of input-current during the first minute and a gradual but persistent rate of decay for the succeeding six or seven minutes indicate that the insulation is in an acceptable condition from the operating point of view. Curves showing little, if any, decrease or a persistent tendency to increase during the time interval of the test indicate that the insulation has deteriorated to such a point that the cable may be expected to fail at an early date if retained in service. The degree of deterioration is indicated first: by the time which has elapsed since complete electrification before the increase occurrs, and second: by the sharpness of the upward trend of the curve in any instance. The value of this method of testing has been demonstrated by its actually having detected a considerable number of impending cable faults before they became a menace in operation. Additional refinements in the methods of measuring the input-current for different classes of cables may be desirable. Further investigations are being carried on to determine this necessity. Investigations of certain theoretical features are also being carried on. These include, among other things, oscillographic studies of the input-current and voltage under test conditions.

Experimental investigation of air flow in rotating blade rows is widely regarded as desirable, but is rendered difficult in practice because of high rotational speeds and the large number of pressure tappings required. The design and operation of a system using the Scanivalve and able to transmit pressures from a rotor running at 8000 rev/min is described in this paper. Some experience in the use of the system with blade surface measurements on a small (8-in diameter) centrifugal impeller is discussed. Attention is paid to sources of error in pressure readings, including the rotating head correction to convert the transmitted pressure reading into actual pressure at the point of measurement. Theoretical relative velocities in the impeller have also been obtained with Algol computer programmes for isentropic flow in the axi-symmetric and blade-to-blade directions. A comparison is made between experimental and theoretical relative velocities in the impeller in which the flow is essentially incompressible at the test speed. It is concluded that flow separation occurs early in this particular impeller channel. On the evidence of the results obtained so far, some further uses and developments of the pressure transmission system are discussed.

(1943). The Chapman Papers: A Note on the Hansom Cab. Transactions of the Newcomen Society: Vol. 24, No. 1, pp. 65-72.

The noise produced by the circulating water pump motors at Blyth ‘B’ power station contained a pure tone and this led to complaints both from the public and from the plant attendants. It was established that the noise was principally magnetic in origin, attributable to an unfavourable combination of numbers of stator and rotor slots, and the noise level was reduced by modifying the design of the rotor to obtain a better slot ratio. The noise level was still undesirably high, however, and an experimental silencer for the cooling air inlets and outlets was designed and a mock-up constructed of timber, hardboard, and mineral wool slab. These combined measures reduced the noise inside the pumphouse to well within the ISO noise rating number 85, which has been taken as the hearing damage risk criterion, and abated the public annoyance outside the pumphouse. This paper describes the basic origin of magnetic noise in squirrel-cage motors and methods for controlling noise levels both by design of motor and silencers within the limits set by electrical and economic design parameters.

Many lubricated machine contacts can be represented by cylindrical surfaces, and some of these contacts such as gears and rolling contact bearings have been studied extensively in recent years within the developing subject of elastohydrodynamic lubrication. When high loads are carried by the contact, side leakage is of little importance, but there is little evidence to indicate the quantitative importance of side leakage when the loads are light. This question has assumed greater importance with the recent recognition that many nominally parallel surface thrust bearings rely upon thermal distortion for their effective load-carrying capacity, since the deformed shape can be approximated by a pad of cylindrical form. In this paper solutions of the Reynolds equation are presented for the geometry of a cylinder near a plane lubricated by an isoviscous fluid. The resulting pressure distribution has been integrated to yield normal and tangential surface force components and the results are presented in the form of side-leakage factors to be used with the Martin solution for an infinite cylinder. The approximate ‘short-cylinder’ theory is presented and compared with the full computer solutions. The results are applied to two lubricated contact situations.

This paper describes an attempt to measure the elastohydrodynamic film thickness generated within the rolling contacts of a conventional taper roller thrust bearing. The technique used is simple and unambiguous and should be capable of application irrespective of the surface finish or geometry of the rolling elements.

This paper covers the design history of an engine family which originally spanned a capacity range of 1000–1390 cm3 but has lately been extended to 1500 cm3. The requirements which governed the basic engine design are dealt with from two angles—the vehicle requirements, which determined the cylinder capacity and arrangement and led to the adoption of a water-cooled four-stroke design; and the production requirements, which dictated the need for a ‘family’ concept to give the maximum range of engine capacity from a single tooling set up. Performance, package and durability targets were established and it was essential to meet these while maintaining minimum cost and weight. The layout of the basic engine provides for changes of capacity by variation of the stroke only; the advantage of this method over varying the bore or both bore and stroke is discussed from both product and manufacturing viewpoints. The engines are considerably ‘oversquare’ (large bores, short strokes) and the effect of this and the importance of connecting rod length to crank throw ratio is discussed. The detail design of the cylinder block was influenced by the short stroke and resulted in equally spaced cylinder centres and main bearings of ample capacity being incorporated. A unique treatment of the push rod ‘chamber’ was adopted to eliminate coring. The cylinder head has individual ports and fully machined combustion chambers with vertical valves and this layout made possible a single piece water jacket core. For the crankshaft, a hollow nodular iron casting was chosen and the very short strokes enabled balance weights to be omitted without bearing loads exceeding the limits of modem materials. In laying out the ancillary components an unusual arrangement for the oil pump and filter was chosen with advantages of easy assembly and servicing. After production of the engine family had commenced in 1000 cm3 and 1340 cm3 versions, the need for a 1500 cm3 version arose. This was achieved within the basic framework of the original design by a further increase of stroke, but required some increase of cylinder block height to maintain a reasonable connecting rod length. Production tooling was fortunately able to accommodate this change and because of the equal bore and bearing spacing in the original design, it was possible to incorporate five main bearings.

This paper describes investigations that were undertaken to identify the reasons for fatigue failures in cast iron and aluminium pistons of large diesel engines. The work involved experimental and theoretical stress analyses, and fatigue tests were made on specimens cut from actual pistons. It was found that four pistons which suffered fatigue failures had safety factors of 0·60, 0·68, 0·94, and 0·96, while three modified designs which performed satisfactorily were assessed to have safety factors of 1·1, 1·24, and 1·57. Special attention is drawn to the method of fatigue testing in which features typical of the piston are retained. While it is considered prudent to design for safety factors substantially in excess of unity, the results presented should promote confidence that this approach to the design of components is valid not only in this case but more generally.

In this paper some recent development work on a high output air-cooled two-stroke cycle compression ignition engine designed for a military tank is given. This engine develops a maximum gross output 870 PS (858 hp) from 21·5 litres (131 in3) of cylinder volume at a speed of 2200 rev/min. Exhaustive development was necessary for this new engine to ensure satisfactory performance and excellent durability.

Professor Buyniak's careful survey is the most complete history to date of Slavic Studies in Canada. A commentator will hardly improve on his thoroughness, but he can voice a few hopes and add a few critical observations which would normally not have a place in a factual study of this kind. The first observation to be made is that Slavic studies, like other area studies, have gone through a period of growing pains, marked not merely by lack of funds and foresight on the part of university administrations, but also by difficulties inherent in venturing into unfamiliar grounds. The profession should perhaps face the fact that the distrust on the part of university administrations in the early years was not only due to short-sightedness and a built-in conservatism, but in part to the absence of qualified Slavic scholars. During the first post-war years many appointments were made, even senior appointments, that were the result of a hasty and improper appraisal of candidates for academic positions. Indeed, there were no precedents for evaluating the credentials of Europeans eager to teach in Slavic Studies, and brandishing unfamiliar certificates of proficiencyor sometimes with no certificates at alland demanding academic positions on the strength of them. The consequences of appointments made on the basis of such credentials were sometimes painful and caused administrators for years to look askance at the whole profession, withholding their trust and their funds from the doubtful and the deserving candidates alike. It is gratifying to be able to say that this period is now definitely over; new appointments are being made on the basis of the same criteria as in other fields and the growing output of scholarly works bespeaks the growing strength and quality of the profession. In this connection, it may be pointed out that students of "purely" Anglo-Saxon origin are beginning to take interest in Slavic Studies and this augurs well for the future: only they can furnish a durable basis for the development of Slavic Studies. Another observation is in the nature of a caveat: there is dangerand that danger is not lesseningthat Slavic specialists will be drawn into the duels of the Cold War and will, in fact, become its instruments.

Although the complete fuel injection system is a critical feature for the reliable operation of all diesel engines, various applications place a different emphasis on service requirements; particularly with respect to nozzle and injector life. This paper deals with a number of rail traction problems which have arisen in the field where improvements in nozzle/injector life have been needed for both technical and economic requirements. One specific problem—that of injector spring failure—is covered in more detail. A study of spring dynamic behaviour has been made which shows that normal spring ‘surge’ theory does not adequately explain spring failure. A simple expression is derived indicating that injector spring dynamic stresses are independent of spring design parameters and are a function of nozzle needle velocity only.

The paper presents the results of intrascope observations and instrument traverses in the final stages of three large steam turbines and describes the processes controlling the distribution of erosion on the moving blades. Concentrations of eroding water are shown to be produced by complex steam flows in the final stage which redistribute the water depositing on the surfaces of fixed blades. Of the three turbines considered, each has a different redistribution process, two leading to concentrated erosion, the third to a more uniform distribution of damage. In the former two turbines, it was found that the concentrations of water could be dispersed by small fences fitted to the fixed blade trailing edge, this simple modification promising to extend significantly the operating life of the moving blades.

This paper outlines a new approximate theory for liquid lubricated plain journal bearings with elastic liners. This is a modified form of Ocvirk's theory and includes the effect of circumferential flow. The results of a series of tests on short plastic bearings are presented to compare with the theoretical predictions of the new theory. The authors conclude that for short bearings the theory gives reasonably good predictions of performance, but the elasticity assumptions cause major errors for length/diameter ratios greater than 0·5 due to the decrease in oil film thickness that occurs near the ends of the bearing. The approximate solution adopted for the hydrodynamic problem may be of use for considering dynamic conditions taking the Reynolds conditions for cavitation.

(1923). Thirtieth Annual Convention, American Physical Education Association-Papers Continued. American Physical Education Review: Vol. 28, No. 8, pp. 355-361.

Abrasion is generally defined as wear caused by fine solid particles. In this paper the term abrasion will refer only to wear caused by hard particles introduced into and entrained by a fluid flowing between two solid surfaces, the particles possibly becoming embedded in one of these surfaces. For the study of this type of wear a plain journal bearing was considered suitable. Arguments for this choice and a description of the apparatus are given. The use of an aerostatic bearing for the application of load to the plain journal bearing has made friction torque measurement feasible. The abrasives used were silicon carbide particles of very narrow size distributions; the carrier fluid was a mixture of a straight mineral oil and n-hexadecane. The wear of the shaft was determined by measuring its surface profile, the wear of the bush by measuring its deviation from roundness. Various combinations of materials were investigated. In most cases hardened steel shafts and soft bronze bushes were used. In addition, some plastic materials served for the bushes; steel, bronze, and aluminium were applied both as bush and as shaft material. Embedding of particles was observed at various places in the bushes, which were usually softer than the shaft. Additional information on the wear processes was obtained by microscopical inspection of the worn surfaces. Results of the experiments are discussed.

In this paper, the engineer is introduced to the problem of noise, its measurement, and its control in hydraulic systems. The causes of noise are outlined, and an examination is made of the design of circuits, including consideration of the suction and delivery lines, valves and components, pumps and motors and the development of acoustic filters. The development of a pump designed for quiet running is described.

Single-service paper containers for milk are being used more widely each year. The effect of sunlight on the flavor of milk stored in such containers has not, however, been studied extensively; and few data are available in the literature on this subject.

A survey has been carried out in 72 lecture rooms to investigate the effect of ventilation system noise. In many cases the systems have to operate at reduced speeds to permit tolerable noise levels and the reduced air volume results in the rooms becoming overheated. A lack of knowledge among architects and consultants, a misapprehension about the cost of providing sound control and the non-specification of acoustic standards appear to be the main reasons for this trend. This paper presents details of the characteristics of ventilation system noise and also suggests proposals for future work which will cover the acoustics of high-velocity air conditioning systems.

This report deals with an investigation of eddy-current losses in multi-core circular-conductor and shaped-conductor paper-insulated wire-armoured cables, and the development of formulae by means of which the losses can be computed. The experimental work covers tests with balanced three-phase currents at frequencies from 25 to 300 cycles per second. The eddy-current losses are divided into four parts, namely, skin effect, proximity effect, lead-sheath effect, and armouring effect. The ratio of a.c. to d.c. resistance of the conductors, calculated by the appropriate formula, is, with one exception, within 5% of the measured value under all the conditions covered by the investigation, the average difference between calculation and measurement being only 1%.

A. E. Kennelly: Turning to the paper by Dawes and Hoover, it seems to me that the great force of that contribution lies in the fact that a bridge has been developed which employs a vibration galvanometer, with all the delicacy and precision that the vibration galvanometer affords, so that instead of having to employ a relatively great length of cable dielectric for test, it is sufficient to have only, say, a couple of meters, provided that the particular couple of meters shall represent fairly well, the whole length of a cable under consideration.

The purpose of this short paper is to give an exact theory of quarter-wave coupled circulators with Chebyshev characteristics. The synthesis starts by replacing the lumped-element equivalent shunt resonator of the circulator by a distributed one that has the same susceptance slope parameter as the original circuit. In this way the overall network involves commensurate transmission lines only. The bandwidth over which the assumed form of the equivalent circuit applies is carefully discussed in terms of the two split frequencies of the magnetized junction. Tables for the required circulator parameters and transformer admittances for one and two transformer sections as a function of VSWR and bandwidth are included. The realizable solution for the latter arrangement is severely restricted by the equivalent circuit of the basic junction. Experimental results on an octave-band stripline circulator, with a two-section transformer, are also included.

This paper presents a theoretical and experimental assessment of the eight coefficients which describe the stiffness and damping properties of journal bearing oil films, together with their subsequent use in predicting the performance of a real rotor. The performance is checked experimentally.

Summary To conclude this paper, the most important points may be summarized as follows. Firstly, pollution by dairy effluents will have to be stopped, not only for reasons of good public relations, but also because of impending trouble for future offenders when recent legislation begins to take effect. Secondly, the best and cheapest way of reducing the size of the problem is to reduce losses in the dairy of milk solids of all sorts, especially by-products of low cash value but high polluting power. Thirdly, direct disposal of the remaining effluent is always best, where possible, but the only method of doing this which can be unreservedly recommended is by a pipe-line to the sea or to the sewer of a willing Local Authority. Direct disposal on land may be a tempting method financially, but is only satisfactory in exceptional places, and is always a potential source of complaints from neighbours. Fourthly, for most dairies some kind of effluent purification treatment is unavoidable. At small non-manufacturing dairies, where sludge disposal is not too difficult, the chemical precipitation process followed by irrigation has the advantage of simplicity and low capital cost. If space is limited, single biological filtration can be used for the final stage instead of irrigation. Scarlett's process of aerobic fermentation followed by biological filtration seems more suitable for larger dairies. The activated sludge process is relatively compact and cheap, but is unsuitable for manufacturing dairies with fluctuating load. Of the various biological filtration systems, in our experience the method of choice, when the load is heavy and where a high quality effluent is essential, is undoubtedly the double-alternating system. It is unfortunately also very expensive. The cost of filter beds, which is the largest item, can be reduced by using one of the high-rate systems, but these usually involve a bigger sludge disposal problem and an inferior effluent. Finally, I would like to repeat a plea often made before. An effluent plant should be regarded as part of the normal dairy equipment, and should be cared for like the rest of the factory. It should not be thought of as a mere nuisance, or something to be fitted and forgotten. In our experience, the effluent plant that is best looked after gives the least trouble and the best results. This is not achieved by putting it in charge of the most incompetent odd-job man in the factory, who is thought fit for nothing better than sewage.

THE capital investment in the underground cable system of any large metropolitan utility is so great that any means of increasing its usefulness is of great and immediate interest. The operation of paper-insulated cables at higher copper temperatures than are accepted as normal, offers one obvious means of increasing the usefulness of the cable system where voltage regulation does not limit load.

Direct-current capacitors of the impregnated-paper type play an important role in electronic equipment required by the Armed Services. In some of these applications good performance is required over very wide temperature ranges. A new chlorinated-hydrocarbon composition which maintains reasonable capacitance constancy over a wide temperature range is described. The properties of this liquid are compared with conventional chlorinated impregnants. Since some alternating voltages usually accompany the direct voltages applied to capacitors, the alternating-current behavior over wide temperature and frequency ranges is described for capacitors impregnated with three different liquids. The effect of voltage and temperature on the resistance of capacitors is discussed. Considerable attention is devoted to the life behavior of capacitors impregnated with chlorinated liquids under direct-current stresses at high temperatures. A life-testing procedure is described which has yielded very satisfactory results on capacitors of varying sizes and ratings. A means for prolonging the life of capacitors impregnated with chlorinated impregnants involving the addition of stabilizers is discussed. Data showing effect of a number of stabilizers are presented. Finally, some data are presented showing the effect of voltage on the life of direct-current capacitors.

This paper (which is a continuation from Parts I and II) shows that by the application of a suitable negative grid bias through a swamping resistor, any type of triode may be employed in the Chromatograph circuit of Blake's electrostatic zone locator. By the inclusion of a relay (which operates an electromagnetic marking device) in the anode circuit of the valve, the zone locator works automatically as the Chromatograph is pulled across the electrodes by means of a small motor. Each zone or spot is underlined automatically and leaves the locator ready for excision and analysis by solution comparison. It is shown by a resistance-anode current graph that the resistance at the extreme edges of a spot of CuCl2 is of the order of 1400 megohms which as the electrodes are bridged operates the relay satisfactorily.

It is generally accepted that the performance of compensated externally pressurized journal bearings is superior to ordinary journal bearings. This paper presents the experimental results of performance studies of compensated and uncompensated journal bearings under static and alternating loading with an operating frequency of 327 c/min. The length/diameter ratio of the test bearings was 1/3 and both bearings had 10 closed-end grooves machined in the bearing surfaces. Film pressure surveys reveal considerable differences in the film pressure distribution in the two bearings, and explain the difference in the performance characteristics of these bearings. Comparisons are made in terms of measured load capacity, stiffness, and lubricant flow rates. The relative costs of manufacture and the operating costs of these bearings are also discussed.

The fluid film bearing designer is encountering situations of turbulent lubrication with ever-increasing regularity. This paper is not concerned with the fundamentals of turbulent lubrication but more with an assessment of the methods available to the bearing designer for the examination of turbulent flow conditions and with the effect of turbulence. The two main ‘engineering’ approaches to turbulence are delineated and their quantitative predictions compared for the case of a finite width plane inclined slider thrust bearing hydrodynamically lubricated with an isoviscous incompressible fluid.

The paper deals with large slow-speed marine engines with a section on crankshaft stresses, including dynamic torque calculation; static bending moments owing to firing pressure, inertia, and misalignment; combined torque and bending stress; and experimental determination of stress concentration factors in the fillet radii. Other sections deal with top end bearing loading including cyclic variation, piston head stresses, deflection of bearing housings, prestressing of main bolts, frame stiffness, and stress in combustion chamber studs as a result of pressure and thermal loading.

This paper gives an outline of the design and development of the 750-b.h.p. prototype glandless boiler circulating pump to be commissioned at Kingsnorth Power Station. Suction conditions of 2650 lb/in2 (gauge) and 650°F demanded special techniques for the maintenance of safe motor winding temperature levels under all types of operation. Constructional details of the high-pressure casings and the rotor system, employing water-lubricated bearings, are discussed, together with those of the auxiliary cooling system. Comprehensive prototype tests were carried out to prove the principal design features. Particulars of the test rigs used and the results obtained from them are given.

The paper deals with the problems of turbocharging the two-stroke cycle engine. Obtaining a sufficiently rapid drop in the pressure of the cylinder contents after exhaust port opening is chiefly dependent on obtaining a high turbocharger efficiency. However, exhaust-pipe design can be very important in this process, and a system is described which permitted the use of simple turbocharging from light load to 200 lb/in2 b.m.e.p. Good starting and acceleration demanded that energy be fed into the charging system and so the normal engine-driven Roots blower was then fitted as a second stage. This spoiled the good natural match of the turbocharger and engine but it was discovered that by control of air recirculation through the Roots blower a good match could be obtained. The work showed that the best match leads towards a constant horsepower type of engine torque curve, and this fact should be recognized for future vehicle design. The use of two turbochargers in series offers very high outputs with good efficiency but will require a new generation of engines to withstand the high pressures and thermal loading.

This paper describes some of the results obtained from a series of experiments on internally air-cooled turbine nozzle and rotor blades. These were formed by an extrusion process and had, respectively, sixteen and thirteen cooling passages of approximately elliptical cross-section. The cooling characteristics of both types of blade were measured in an experimental high-temperature turbine and further experiments were conducted in cascade tunnels. Some of the cascade experiments on the rotor blade were conducted at comparatively high Reynolds numbers and showed, in accordance with predictions, the extent to which chordwise non-uniformities in blade temperature become larger as Reynolds number is increased. Other experiments were conducted with the turbine to determine the effects on aerodynamic performance of discharging spent cooling air into the main gas stream. The results showed good agreement with predictions based on a simple flow model, and in particular indicated that flow separation, with its associated losses, did not occur. Finally the results of an endurance test are presented, together with a brief description of the way in which thermal plus centrifugal stress patterns can be redistributed by creep in non-uniformly cooled blades. Brief mention is made of those fields of research which require further attention, namely an investigation of the factors governing the local values of heat-transfer coefficient on the external surface of turbine blades and the testing of the assumptions used in calculating stresses in cooled blades.

The investigations described in the present paper deal principally with the phenomena of annealing. They form a continuation of the research described in the Bakerian Lecture for 1899 (‘Phil. Trans.,’A, vol. 193, 1900, pp. 353-377). In iron, steel, and brass these phenomena have been studied with the aid of the microscope by various workers, among whom Arnold, Charpy, Stead, and Roberts-Austen should be particularly mentioned. As a result of their labours it is well known that annealing is accompanied by a re-arrangement of the crystalline grains of the metal. Thus, when a piece of iron is strained in tension its crystalline grains become elongated in the direction of tension ; but when the specimen has been subsequently annealed by being heated to a bright red, all signs of such elongation disappear from the crystalline pattern revealed by the microscope. In fact it is not generally possible to find any definite connection between the crystalline pattern seen in the same specimen before and after annealing. In general, the pattern seen after annealing resembles that found in a similar specimen before it has been strained, but the scale and character of the pattern produced depend very much on the details of the annealing process, particularly upon the temperature applied, the time of its application, and the rate of cooling. Arnold and Stead have shown that prolonged annealing tends to produce large crystals in iron and steel. But even short exposure to a suitable temperature is well known to produce complete re­crystallisation, and it has been suggested that these changes occur at critical points corresponding to the “arrest-points” in the cooling of the metal. These arrest-points indicate evolutions of heat, and it is natural to suppose that they are evi­dences of re-arrangement of the structure of the metal.

The paper covers the constructional considerations, design and development of the engine to be installed in a rear-engined vehicle. The need for minimum weight and size coupled with adequate power output resulted in the decision to use light alloy diecastings wherever possible. The various methods of diecasting are considered and the methods used for the various components are discussed with the reasons for their use. Problems with cast-in cylinder liners, machining considerations and the implications of laying the engine at an angle in the car are covered. With regard to performance, several factors are discussed: the reasons for adopting the four-stroke cycle, four cylinders, water cooling; determination of capacity from power required data; the use of a single overhead camshaft; combustion chamber shape and compression ratio; port shapes and determination from air flow research. Then follow the various stages of development work and endurance testing.

Over the last 15 years the synchronous drive belt has become an established part of the power transmission scene. It is not a direct substitute for any of the more traditional transmission media; the unique properties of the belt make it complementary to them. This paper describes the current state of the art mainly from an industrial application point of view. This approach necessarily includes certain production information and the background to the power rating table.

This paper describes the problems encountered in the design, operation, and calibration of a small momentum balance fitted within an isokinetic sampling probe located in the test section of a wet steam ‘wind’ tunnel. The probe is suitable for use in air, dry steam, or wet steam. It has an opening of ½ in diameter, a maximum diameter of 1¼ in, and a length of 4½ in, and will detect momentum forces greater than 0·001 lbf. The signal is transmitted by causing the impulse cage to compress a bellows. Turpentine enclosed therein raises the level of its meniscus in a capillary tube and the change in level is observed with a micrometer microscope. An electrical superheating calorimeter is employed in series with the impulse-measuring probe to determine the stagnation enthalpy of the sample. Results are reported for air and steam. For steam the ranges of the respective variables are: pressure, 20–25 inHg vacuum; velocity, 200–500 ft/s; and wetness, 0–10 per cent by weight. Owing to the small size of the momentum cage it was not possible to isolate the contribution to the total momentum made by the entrained liquid.

To prevent or minimize the erosion of the last row rotor blades in large high-speed steam turbines it has been proposed to remove the film of water on the surfaces of the last row stator blades before it reaches the trailing edges and is swept off by the steam drag into the path of the rotor blades. The paper describes experiments with a cascade of hollow stator blades with various dispositions of slots providing communication from the blade surfaces to the hollow cavity. The same cascade was used in turn with three different wet air tunnels, the experiments thus covering a wide range of Mach number and Reynolds number. With suitably disposed slots, and bleeding a very small proportion of the working fluid, about 90 per cent of the deleterious water can be removed, thus preventing it from striking the moving blades.

As the size of steam turbo-alternators has so rapidly increased, the diameter and surface speed of the journal bearings are such as to cause the oil film to become at least partially turbulent. Little information is available on the performance of large bearings operating in the transition and turbulent regimes and it became necessary to undertake a research programme on a full-size test rig. The apparatus was designed so that bearings of various geometries could be tested under both static and dynamic loads. This paper describes some of the static load tests on a 24-in diameter by 18-in long bearing and is confined to describing the factors influencing the transition from laminar to turbulent flow in the film. An analysis of the results indicates that even at low speeds there is a dependence on the Reynolds number and it is suggested that the inertia of the oil film has a pronounced influence. The transition to turbulence is delayed by axial flow and shaft eccentricity, but is ultimately precipitated by the effect of eddies in the oil supply channels and in the grooving.

The researches detailed in the present paper were commenced in May 1871. The results arrived at were largely obtained from using the microscope. Similar but less brilliant and more scanty appearances can be obtained with the telescope; but the very high power and ready adaptability of the former confers some advantages not offered by the latter. In both, however, the same principles are illustrated. A cone of rays of small angular aperture having the object-glass for its base in each case engages the eyepiece and emerges parallel, and the eyepieces are similar in each.

Pressure–volume diagrams, usually associated with reciprocating machines, are valuable both as a means of investigating performance and in providing information for further design work. This paper describes the main features of a method for compiling rotor cell pressure–volume diagrams for sliding vane rotary compressors. Diagrams obtained for various compressor operating conditions are given and discussed.

This paper reviews some of the problems associated with lubricants for bearings and gears in aero gas turbines operating under severe conditions. The physical limitations imposed on oils by the requirement for high thermal stability are discussed in relation to the necessity for adequate gear lubrication at elevated temperatures. An outline is given of the effects which lubricant additives can have on oil performance in bearing and gear tests. Some adverse side effects of otherwise beneficial additives are pointed out and finally a brief account is given of the methods employed to improve the resistance of oils towards oxidation at high temperatures.

The paper deals with a computer program that has been developed to study the dynamic behaviour of poppet valve mechanisms. A theoretical analysis is performed on a single mass, single degree of freedom system subjected to internal and external viscous damping and Coulomb friction, representing a valve mechanism with flexible overhead linkage. Measurements have been made on engines so that computed and experimental results could be compared in order to test the program. The effect on performance of varying the dynamic parameters of valve mechanisms is investigated with the computer program.

The rapid increase in blade-tip diameters and peripheral speeds of low pressure turbines in large 3000 rev/min turbo-generators has presented the designer with many difficult mechanical and aerodynamic problems. To assist in the aerodynamic development of such blading, design studies on an experimental low pressure (l.p.) turbine were started early in 1959. Economic and technical considerations limited the choice to a one-third scale model steam turbine capable of running at three times the normal rotational speed to preserve full-scale working Mach numbers on the blading. Overall output and steam consumption were measured on a hydraulic dynamometer and by volumetric tanking respectively. The inlet steam temperature was controlled by a direct injection desuperheater so that the expansion could be kept dry for traversing or reduced to design inlet temperatures for normal wet running. Three multi-stage sets with last row blade diameters corresponding to 90-in, 120-in, and 136-in full-scale turbines have now been tested in the experimental turbine and the wet performance of the largest forms the subject of this paper. The overall wetness losses on the model 136-in diameter turbine have been assessed from a series of seven tests in which the inlet superheat and rotational speed were varied whilst maintaining fixed inlet and outlet pressure levels. To isolate the stage moisture correction factor (α), however, where a stage-by-stage approach was adopted, in which the dry stage efficiencies were initially established from interstage traverses under dry steam conditions. Two wet steam analyses were made, the first assuming equilibrium and the second supersaturated expansion, but the choice seemed immaterial since the moisture correction factor was almost the same for both. In the case of the supersaturated expansion calculation, it was necessary to establish the point of reversion from supersaturated to near equilibrium expansion (the Wilson point) and supplementary water extraction results were used to establish the maximum supersaturation ratio. These suggest that the maximum level is nearer to 3 in the model turbine than to the value of 4–6 quoted for convergent-divergent nozzles.

In this paper the author presents the historical development of Polish scientific research work in the field of surface metrology and especially the recent work of the following Research Centres: Cracow: working in the field of methods and accuracy of surface roughness measurements, and particularly an investigation to determine the optimal sampling length, interdependence of Ra and Rz values after machining, indication accuracy of surface analyser, and the so-called ‘purposeful accuracy’ of measurements resulting from the heterogeneity of roughness. Wroclaw: working in the field of accuracy of interference roughness measurements and construction of micro-interferometers. Warsaw: working in the field of surface topography and its bearing properties under variable loads.

Experiments have been undertaken at selected electrical loads on a self-contained turbo-alternator set comprising a 350-kW 60-c/s alternator driven by means of double helical parallel shaft gearing by a high-speed (15 000 rev/min) steam turbine. The turbo-alternator was erected on flexible mountings with all steam, water, and other service connections arranged in such a manner that they placed no constraint on the machine. In addition to the turbine and alternator rotors several auxiliary drives each contribute to the total noise output. These include the d.c. exciter, pilot exciter, and metadyne unit which are driven directly, or by belts, from the alternator shaft and the oil pumps, governor, etc., which are driven from the turbine shaft by way of spur and bevel gears. The paper describes the manner in which the separate effects of each of the major sources of structural vibration and airborne noise were isolated and measured. In-place balancing techniques were employed to aid an investigation of the variation of vibration level with rotor out-of-balance. In the process experimental information was obtained about the damping effects of journal bearing oil films, vibration amplitudes of the bearing housing being as much as 25 dB below the equivalent shaft amplitudes.

Several procedures for designing externally pressurized journal bearings have been presented. These vary from simple approximate solutions based on the bearing stiffness in the concentric position to full relaxation programs. In this paper the authors compare the predicted performance of bearings with experimental results. In addition to the static results obtained by the authors on a typical four-pocket grinding spindle bearing, the dynamic results of Patrick and Chen are also treated.

This paper discusses alternative approaches to the use of the laser as a metrological tool, and considers the particular qualities required of it when the laser beam is to be used as the reference. Ways in which its usefulness can be extended by associating it with other optical equipment in order to measure parameters other than straightness are referred to. In conclusion some consideration is given to the limitations imposed by the atmosphere upon instrument performance and the ways in which, in part, they can be countered.

About four years ago Cummins Engine Company embarked on developing a family of new turbochargers, employing similar design principles which emphasize a minimization of size, weight, number of parts, and manufacturing costs, concomitant with good aerodynamic performance and outstanding reliability. The resulting series of turbochargers is characterized by an extended vaneless diffuser, asymmetrical compressor volute, a simple V-clamp tying the compressor to the turbine, as well as novel features in the bearing and bushing design of these units. This paper describes the analytical studies, design features, and some performance aspects of this new family of turbochargers.