bluuebunny/crossref_metadata_2025 huggingface dataset:
The Arroasian Order in Medieval Ireland
Authors: Dunning P. J
Published: August 2016

The Arroasian order was one of the most important of the twelfth-century congregations of canons regular of St Augustine. The development of the institute of the canons regular may be said to have had two phases. From early christian times it was comparatively common for communities of priests, forming the staff of cathedral or large city churches, to imitate the monastic rule of life. In the general disorder which followed upon the barbarian invasions this practice disappeared. It was revived again under Charlemagne, only to suffer a similar fate on the break-up of his empire. At this stage we find secular priests performing collegiate and parochial work while living a regular life under a rule usually given them by a bishop.
Irish Seasonal Migration to Great Britain, 1800–38
Authors: Kerr Barbara M.
Published: August 2016

It is seldom possible to date accurately the beginning or end of population movements. It is doubtful whether the migration of Irish harvesters to Great Britain was very extensive before the end of the eighteenth century. At the close of the century, however, conditions were such as to render the migration desirable to the English farmers, and a necessity to the Irish peasant. By 1827 so desperate was the situation of the latter that a witness could declare before a parliamentary committee on emigration, that ‘ every decrease in the number coming to England each year would add to the probability of starvation in Ireland ’. The year 1838 has been taken as the closing date of this study since it saw the introduction of the first remedial effort (the Irish poor law act).
Nasal airflow and brain activity: is there a link?
Authors: Price A , Eccles R
Published: August 2016

Background:

Over the past few decades, evidence has emerged suggesting that nasal airflow asymmetry and brain asymmetry are linked. The nose exhibits asymmetrical airflow, with the dominant airflow alternating from one nasal passage to the other over a period of hours. Some authors have suggested a correlation between cerebral hemisphere dominance and nostril dominance. Others have proposed an association between rhythmic fluctuations in nasal airflow and corresponding fluctuations in cerebral hemisphere activity. Based on ancient yoga breathing techniques, newer evidence suggests that altering nasal airflow can influence brain activity, with reports of improved cognitive function caused by unilateral forced nostril breathing. It seems that a nasal airflow stimulus may have an activating effect on the brain, as it has also been shown to trigger seizure activity in epileptic patients.

Objectives:

This article explores these theories in detail, reviews the evidence, and presents new models linking nasal airflow and brain activity.
Intravenous Thrombolysis for Acute Ischaemic Stroke in Young Adult Patients
Authors: Poppe Alexandre Y. , Buchan Alastair M. , Hill Michael D.
Published: August 2016

Background:

Intravenous tissue plasminogen activator (IV tPA) has been studied primarily in patients over age 50. We sought to describe baseline differences in adult patients ≤50 years-old taken from a large prospective cohort of acute stroke patients treated with intravenous tPA (IV tPA) and to determine whether outcomes differed for this population.

Methods:

Data (n = 1120) prospectively collected from the Canadian Alteplase for Stroke Effectiveness Study (CASES) were reviewed and patients aged ≤50 years-old (n=99) were compared with those aged >50 years (n=1021) with regards to baseline characteristics, symptomatic intracerebral haemorrhage (sICH), functional outcome at 90 days and death.

Results:

Nine percent of patients were ≤50 years-old. Among patients aged ≤50 years, 40.4% were women and median age was 42 ± 6.1 years (range 20 to 50). They had significantly more current cigarette use but fewer other vascular risk factors than older patients (p<0.05) and their baseline median NIHSS score was lower (13 versus 15, P=0.001). Although this group was more likely to have a favourable 90-day outcome, multivariable regression confirmed that age ≤50 years, while independently associated with a decreased risk of death (RR 0.36, 95% CI 0.14 to 0.95), was not itself predictive of favourable 90-day outcome or decreased risk of sICH.

Conclusions:

Adult patients ≤50 years-old had fewer medical co-morbidities and a modestly lower baseline median NIHSS score than their older counterparts. Age ≤50 years was independently associated with a decreased risk of death but not with favourable outcome or risk of sICH.
The Determination of Turbulent Skin Friction by Means of Pitot Tubes
Authors: Preston J. H.
Published: August 2016

A simple method of determining local turbulent skin friction on a smooth surface has been developed which utilises a round pitot tube resting on the surface. Assuming the existence of a region near the surface in which conditions are functions only of the skin friction, the relevant physical constants of the fluid and a suitable length, a universal non-dimensional relation is obtained for the difference between the total pressure recorded by the tube and the static pressure at the wall, in terms of the skin friction. This relation, on this assumption, is independent of the pressure gradient. The truth and form of the relation were first established, to a considerable degree of accuracy, in a pipe using four geometrically similar round pitot tubes—the diameter being taken as representative length. These four pitot tubes were then used to determine the local skin friction coefficient at three stations on a wind tunnel wall, under varying conditions of pressure gradient. At each station, within the limits of experimental accuracy, the deduced skin friction coefficient was found to be the same for each pitot tube, thus confirming the basic assumption and leaving little doubt as to the correctness of the skin friction so found. Pitot traverses were then made in the pipe and in the boundary layer on the wind tunnel wall. The results were plotted in two non-dimensional forms on the basis already suggested and they fell close together in a region whose outer limit represented the breakdown of the basic assumption, but close to the wall the results spread out, due to the unknown displacement of the effective centre of a pitot tube near a wall. This again provides further evidence of the existence of a region of local dynamical similarity and of the correctness of the skin friction deduced from measurements with round pitot tubes on the wind tunnel wall. The extent of the region in which the local dynamical similarity may be expected to hold appears to vary from about 1/5 to 1/20 of the boundary-layer thickness for conditions remote from, and close to, separation respectively.
Supersonic Flow in Turbines and Compressors
Authors: Sorg K. W.
Published: August 2016

Whereas a body of theoretical research is available on the conditions of supersonic flow through Laval nozzles and around aerofoils, such is lacking for turbo-machinery in general, with the exception of some researches by Stodola, confined to axial steam turbines. The present paper investigates some important questions relating to the flow at supersonic velocity through centrifugal machines of the general type.
A Method of Rapidly Estimating Propeller Moment
Authors: Payne P. R.
Published: August 2016

Propeller moment is the name given to a dynamic phenomenon which causes considerable trouble in the design of variable pitch propellers and helicopter rotors. The development of the fundamental equation has not previously been published, to the author's knowledge, and for this reason the steps leading up to it are given. The propeller moment on any section tends to place its major axis in the plane of rotation, and the fundamental equation is equation. Its use to determine the total moment at a blade root results in lengthy calculations, with the possibilities of delays and errors.
Maintenance Difficulties in the Field
Authors: Kemper M. J.
Published: August 2016

The recent war has provided a great deal of experience in the operation of aircraft and ground equipment under a variety of conditions. This paper is an attempt to condense and correlate some of the points noted into a logical sequence. It is not based on statistics and is more in the nature of a selection of problems and impressions about them. Possibly this is an advantage, as it seems doubtful if many logical conclusions could be drawn from a set of completely comprehensive observations, even if these were available.
Heat Transfer Equations for an Air-Air Heat Exchanger
Authors: Annand W. J.
Published: August 2016

In a recently published book, The Aerodynamics of Propulsion, by Küchemann and Weber, there is included a brief discussion of heat flow in an air-air heat exchanger. The treatment given rests on an assumption which appears to be generally accepted, but which seems to the present writer to be physically unsatisfactory and to yield at least one misleading result. It is the purpose of the present note to show that a solution of the heat transfer equations can be obtained using an alternative assumption which seems physically more acceptable.
The Flight Envelope of a Helicopter
Authors: Payne P. R.
Published: August 2016

The only simple method of estimating the tip speed limitations imposed on a rotor by retreating blade stall on the one hand, and compressibility losses on the other, is that given by Hafner. It suffers from the lack of accuracy always inherent in a “standard radius” method, and for present-day use a more refined approach is obviously desirable, provided that it still enables rapid estimates to be made.
The Effect of a High Speed Dive on the Aircraft Power Plant
Authors: Baker L. J.
Published: August 2016

The introduction of German “Stukas“ has been one of the great surprises of the present war. By means of this weapon, daring men, with the true fighting spirit, have already obtained innumerable successes of the greatest importance on all fronts. These results could not have been achieved but for the conviction that German scientists, and engineers had so perfected the design of this divebomber that it could withstand the exceptional demands made on it—especially on the engine and airscrew.
Progress in Sailplane Design
Authors: Wilkinson K. G.
Published: August 2016

Compared with the general advance of aeronautics in the past decade, or indeed with sailplane development in the 20's and 30's, progress in sailplane design has recently been very leisurely. This is due in part to the fact that there is less scope and partly because little effort has been expended. The most important advances in the art have been in the understanding and use of meteorological conditions which make soaring flight possible; sailplanes good enough for the purpose have existed.

Before the Second World War the main design impetus came from Germany and Poland and in most current designs the German influence is still strongly evident. Since the war there have been outbreaks of activity in Switzerland (W.L.M.I., Moswey), Canada (where Shenstone and Czerwinski have inspired designs at Toronto) and in the United States. The total effort has not added up to that in pre-war Germany.
Pinned-Pinned Slender Solid Struts with Parabolic Taper
Authors: Turton F. J.
Published: August 2016

In 1917–19, Barling and Webb, Berry, Cowley and Levy, and Webb and Lang discussed the elastic stability of struts of various tapers, but it appears to have escaped notice that one of the few cases in which formal integration is possible is that in which the tapered profile of axial longitudinal sections is part of a parabola; this gives a “ homogeneous linear “ differential equation, i.e., a linear equation of the form f (xd/dx) y = F (x).
A Note on the Limitations of Aircraft and Aerofoils used for High Flying Aircraft
Authors: Williams J. A. C.
Published: August 2016

The formation of shock waves as a limitation in aircraft design has been considered only, as far as the author knows, in the cases of wing sections at low operating lift coefficients and of the airscrew efficiency. There is, however, a further limitation for high flying aircraft in that the small air density causes the aircraft, even at the stall, to travel at a value of Mach number (V/a) which will cause a shock stall to form on the wing. In some cases the aircraft will be able to prevent this shock stall at high CL by flying faster, but in others, due to high wing loading, the wing sections will be shock stalled at all CL values and the only remedy will be to decrease the wing loading.
Ocean Air Transport
Authors: Trippe J. T.
Published: August 2016

That this distinguished gathering has convened here to-day, amid the chaos of a war-torn world, for a lecture on civil aeronautics is indeed a singular expression of the true spirit of our profession. It is, I think, graphic proof of the fact that all of us in aviation are looking forward to the day when the aeroplane can lay aside its duties of destruction and once more assume its truly great role as a constructive force in world civilisation.

I am, therefore, particularly sensible of the privilege of delivering, at this historic meeting, the Twenty-ninth Wilbur Wright Memorial Lecture. Under any circumstances, we in America feel that an invitation to address you, the parent body of the aeronautical profession, is one of the highest honours which can be attained by an individual engaged in aviation.

My role here, of course, is hardly that of an individual. In the narrowest justifiable sense, I can but speak for what has been accomplished by the 7,000 men and women who are the Pan American Airways System.
“Buna” Synthetic Rubber
Authors: Konrad E.
Published: August 2016

Rubber is an indispensable material for the German industry. The yearly consumption is at present about 100,000 tons. For thirty years the German chemical industry has studied the problem of synthetic rubber for engineering purposes, but it has only been in the last few years that the difficulties have been successfully overcome.
Why Shear Webs?
Authors: Cox H. L.
Published: August 2016

At a section of a cantilever distant x from its tip, let the depth of section be h and the bending moment M. Then if all the resistance to bending is concentrated in the flanges the loads in the flanges are ±M/h. If the flanges are inclined at a small angle α these flange loads have a component transverse to the cantilever axis of magnitude Mα/h. Now α=dh/dx and the shear load at section x is dM/dx. Therefore the shear load on the web of the cantilever is dM/dx-(M/h)dh/dx, and, if h/M is constant, the web is not sheared at all.
A Rational Definition of Yield Strength
Authors: Osgood W. R.
Published: August 2016

Explicitly or implicitly the yield strength of a material is often used as a measure of incipient structural damage. With the yield strength determined by conventional methods, however, it cannot be said in general for two structural elements geometrically alike but of different materials that similar loads, producing maximum stresses equal to the yield strengths in the two cases, are simply related to the yield strengths. A definition of yield strength is proposed in this paper which often has the advantage that, for geometrically similar structures of different materials, loads producing maximum stresses equal to the yield strength are proportional to the yield strength.
The Focke Helicopter
Authors: Focke H.
Published: August 2016

The Focke helicopter presents the first successful solution of a problem which has occupied aeronautical science for a considerable time. Details of the record flights carried out last year caused a world sensation and with further development it is not too much to hope that this new type will open up fresh fields which up to now remained closed to orthodox aircraft.
Relaxation and Iteration
Authors: Morris J.
Published: August 2016

In recent years much attention has been devoted to what Professor Southwell has appropriately called relaxation (1) methods in the solution of structural problems. These methods are essentially physical applications of iteration processes for solving simultaneous equations. In this paper it is not intended to discuss the advantages or otherwise of physical relaxation as compared with analytical iteration. The object is to examine the mathematical basis of the relaxation methods and to investigate the conditions of their convergency.
Delays in the Flow of Air Traffic
Authors: Bowen E. G. , Pearcey T.
Published: August 2016

It is becoming recognised that before civil aircraft can operate at high density, the most important problem to be solved is that of traffic control. Methods exist by which a single aircraft can navigate from a distant point to an airport and let down to a safe landing under bad weather conditions. Difficulties arise when several aircraft are involved at once and long delays can occur in the neighbourhood of airports carrying high density traffic. In this paper an analysis is made of the traffic problem in an attempt to clarify some of the factors involved.
Gusts
Authors: Tye W.
Published: August 2016

Until recently the gust requirements laid down by the airworthiness authorities had not caused any serious difficulty in design. This was due to the fact that other loading conditions (manœuvring loads imposed by the pilot) had been more severe than the loads produced by gusts. Over the past few years, various factors have altered this position. Increase of aeroplane speeds, increase of operating altitudes, decrease of the manœuvring loads (in the case of large aeroplanes) and increase of size, have each contributed to raise the gust loads until they have become, in many cases, the main design criteria for the flight structure.
The General Theory of Cylindrical and Conical Tubes under Torsion and Bending Loads
Authors: Hadji-Argyris J. , Dunne P. C.
Published: August 2016

Part 5 continues the theory given in Parts 1–4 in the February 1947 issue of the Journal (pp. 199–269). The present paper deals with the stresses and deformations of conical and cylindrical tubes under arbitrary loading, thus completing the analysis given in Part 4 which dealt only with pure torque.

A remarkable unification of the theory of bending and torsion is achieved. It is shown that the axial constraint stresses, i.e. the corrections to the engineers' stresses, may in general be calculated as if caused by torque about axes different in each mode. The analysis proves that it is in no circumstances correct to calculate the axial constraint stresses from the torque about the flexural axis.

Functions giving the cross-wise distribution of stress are fully worked out for the n-boom tube of arbitrary cross-section and for the singly symmetrical trapezoidal tube with continuous direct stress-carrying covers. The analysis is a considerable extension of the results given for the four-boom tube in Part 4.
The Elastic Stability of a Curved Plate Under Axial Thrusts
Authors: Redshaw S. C.
Published: August 2016

Theoretical critical stresses have been obtained for four cases in each of which a curved panel has been subjected to a compressive stress, parallel in direction to a generator and uniformly distributed around its top and bottom circumferential edges.
On the Art of Dynamometry with Particular Reference to the Measurement of Engine Power in Flight
Authors: Muir N. S.
Published: August 2016

It is safe to say that in no branch of applied science have the difficulties been greater or the process of development more rapid than in aeronautics. By far. the largest factor in the triumph of the aeroplane has been the improved internal combustion engine, a class of prime mover which, generating a maximum of power for a minimum of weight from concentrated fuel, is to-day such an outstanding engineering achievement as to arouse one's curiosity regarding its origin and development.

I cannot find better words, adequately to express my meaning, than those of John Farey (I) in his remarkable book, “On the Steam Engine,” published in 1827. Applying Farey's statement also to internal combustion as we know it, we might well say that in common with the steam engine, “It is an invention highly creditable to human genius and industry for it exhibits the most valuable application of philosophical principles to the arts of life and has produced greater and more general changes in the practice of mechanics than has ever been effected by any one invention in history.”
Rigorous Performance Prediction Without Drudgery.
Authors: Reid Elliott G.
Published: August 2016

A new graphical method of predicting aeroplane performance has been evolved by utilising the unique properties of Eiffel's logarithmic propeller chart. Its substitution for rigorous numerical methods results in the saving of labour without sacrifice of accuracy. Particularly convenient when constant speed propellers are involved, this method yields performance characteristics for altitudes below, as well as above, the critical ones for supercharged engines.

Although coupling of the word “ rigorous ” with any method of aeroplane performance prediction may be somewhat of a misnomer, the title of this paper is intended to identify a method which falls short of complete rigour only to the extent dictated by acceptance of the following simplifying assumptions :—

(1)

That the propeller thrust acts along the direction of the flight path, and

(2)

That lift is equal to weight in steady rectilinear flight.

The amount of labour involved in predicting the performance of a modern aeroplane with even this degree of rigour is so great that methods which incorporate additional simplifying assumptions have come into common use—despite their sacrifice of accuracy to convenience—and the more laborious methods are now rarely employed except in studies of very painstaking character. The desirability of minimising the drudgery of rigorous prediction has long impressed the writer and it is the purpose of this paper to describe a graphical method of attaining that objective.

The principal departure which characterises the new method is the adaptation of Eiffel's logarithmic propeller chart to the construction of available power curves. The use of “ indicated airspeed ” (σ1/2V) and the analogous quantity “ indicated power ” (σ1/2 h.p.) as co-ordinates causes a single curve to represent the power requirements for level flight at all altitudes. Other simplifications arising from the recognition of certain engine characteristics, utilisation of the unique properties of the Eiffel chart and development of a convenient method for evaluating the excess available power (from logarithmic curves) make it possible to eliminate a large portion of the labour previously required for rigorous performance prediction. The method is not only applicable to, but especially convenient in, the case of the constant speed propeller; moreover, it yields complete level flight and climb characteristics for altitudes below, as well as above, the critical altitudes of supercharged engines.
Elastically Encastred Struts.
Authors: Hoff N. J.
Published: August 2016

During the last fifty years much experimental and theoretical work has been carried out on the subject of the failure of struts, i.e., rods under axial compression. Most of this work has been devoted to the case of struts pin-jointed at both ends and only a small part examined the behaviour of rigidly encastred struts. From these investigations we know that in case of very slender struts the critical load for rigid encastrement is the fourfold of that for pin-jointed ends. This difference becomes less with decreasing slenderness of the strut, but even for slenderness ratios usually attained in aircraft framework it is considerable, if high tensile steel is used. In actual framework, compression members being more or less rigidly joined to nodes which may twist elastically, they represent a case between both forementioned extremes and may best be regarded as elastically encastred. Since according to above statements the load which may be sustained by a strut obviously depends a great deal upon end constraint, it is of great importance for design purposes to determine exactly the effect of elastic encastrement.
The Economics of Air Line Operation
Authors: Greig L. T. H.
Published: August 2016

In speaking to you to-night on the Economics of Air Line Operation, I propose to speak primarily from the viewpoint of the operator of an internal air line. I do not mean, by that, that I shall confine my remarks strictly to the various problems encountered by my own particular company, nor do I mean that any opinions which I may express will, of necessity, be of interest only to operators of internal services. On the other hand, I do not intend to venture into the realms of very long distance air routes, such as Empire routes, many of the problems connected with which have already been dealt with in considerable detail by Mr. Woods Humphrey in his interesting series of articles in The Times in May of this year. Such small experience as I have had so far with international flying has convinced me that the political difficulties, which are undoubtedly encountered by many of the national air transport companies, must force upon them policies other than those dictated by strictly economic requirements, and in consequence, must render a true comparison between their operation and purely European flying almost impossible.
The Level of Safety Achieved by Periodic Inspection for Fatigue Cracks
Authors: Shaw R. R.
Published: August 2016

It is currently believed in some parts of the world that the problem of structural fatigue in the case of aircraft having a modern multiple spar wing structure can be safely dealt with by allowing fatigue cracks to develop in service. The typical multiple spar wing has its bending tension area distributed between the “ caps “ of two or more spars and a large number of independent heavy stringers. It is believed in some quarters that complete failure in flight of any one spar boom or stringer due to fatigue will leave the wing with sufficient strength for the aircraft to land safely. This note does not discuss the validity of this belief, nor the level of safety so achieved, but attempts an objective assessment of a problem that arises as a consequence of this belief.
Definition of Specific Impulse
Authors: Greenwood S. W.
Published: August 2016

Regarding the recent Technical Note of Mr. RAsquith and Mr. Whitaker (May 1954 journal):

1. The dependence of the weight of a given mass on location is a sufficient reason for the abolition of the ” weight” definition of specific impulse. This is likely to become increasingly apparent as rockets penetrate further into interplanetary space.

2. It is convenient that the “weight” definition gives values of specific impulse which are independent of the units employed, provided that the units of thrust and weight are the same, for the unit of time employed in the definitions under discussion is the second. This raises the question of whether the unit of time should have been specified in the definitions. It seems to me that an improvement on fundamental grounds would be to define (S.I.)m as thrust per unit mass of propellants consumed per unit time and (S.I.)ω as thrust per unit weight of propellants consumed per unit time.
The Flexural Centre or Centre of Shear
Authors: Jacobs J. A.
Published: August 2016

Professor koiter, in his note (January 1954 Journal) states that I (April 1953 Journal) was “ apparently unaware” of Weber's two papers on the subject, published in 1924 and 1926. I was aware of the papers, having cited them in the bulletin by Seely, Putnam and Schwalbe on “The Torsional Effect of Transverse Bending Loads on Channel Beams.“

Some references in addition to those already cited may be of interest. The unorthodox behaviour of a channel beam in bending was observed and reported by C. Bach in 1909–1910. A. and L. Foppl wrote a section on the “Schubmittelpunkt” in their book “Drang und Zwang.“
Plastics and their Application to Aircraft Construction
Authors: Zhibitsky J. T.
Published: August 2016

Economical organisation and practically inexhaustible supplies of raw material in our country create exceptionally favourable conditions for the rapid development of the plastics industry. The raw material is drawn from the by-products of various branches of the chemical and agricultural industries.

By their technical properties, plastics present many advantages over many other materials. Some of them are as strong as metal, as transparent as glass, and as light as wood. Plastics are endowed with high dielectric properties, great thermo-stability, and low conductibility for sound and heat; they can be machined, pressed, moulded, and have a pleasing exterior.
The Part Played by Skin Friction in Aeronautics
Authors: Lanchester F. W.
Published: August 2016

In Part V of my recent paper, when discussing and tabulating the conditions that obtain at low Reynolds numbers (more especially as concerns the dynamics of flight of the model depicted in Fig. 14), the data shown in Table IX and plotted in Fig. 15 need correction. It appears that in the tabulation an incorrect constant was taken. Furthermore, the distinction which exists at low Reynolds numbers between data secured in the wind channel, in which, generally speaking, wind velocity is constant, and the data relating to a glider in free flight in which W is constant, was not sufficiently explained.
On the Calculation of the Boundary Layer
Authors: Gottingen L. Prandtl
Published: August 2016

The field of viscosity forces in fluid currents of low viscosity—i.e., high Reynolds number—is frequently confined to a narrow zone in the vicinity of the surface; consequently, calculation can be simplified by the following assumptions :—

1. In the friction zone, customarily called the “ boundary layer,” only the most effective components of the viscosity force μΔω, are considered—e.g., for the x component of this force, μΔu (calling the direction of main flow parallel to the surface, the x direction, and that perpendicular thereto the y direction) the expressions μ (∂2u/∂x2) and μ (∂2u/∂z2) can be neglected for μ (∂2u/∂y2).
On a New Theory of free Turbulence
Authors: Reichardt H.
Published: August 2016

Measurements of momentum in regions of turbulent mixing show that an analogy exists between the processes of turbulent and molecular balance which enables a rational application of the differential equation of thermal conduction to the propagation of turbulent momentum to be made. This fact forms the basis of a new phenomenological theory of free turbulent flows.
R. J. Mitchell — Aircraft Designer
Authors: Smith J.
Published: August 2016

I am very conscious of the privilege and honour of being asked to deliver the first R. J. Mitchell Memorial Lecture. The presence of such a distinguished audience, and the fact that I feel the subject is one to which it is difficult to do full justice, are factors which do not tend to fill me with confidence, and I hope you will forgive any inadequacies. From a mass of recollections arising as the result of fourteen years of contact with Mitchell, I hope to give you my impressions of the life and career of that great designer.
The Comparison of a “Wake Brake” and a Parachute for the Landing of Aeroplanes
Authors: Jackson S. B.
Published: August 2016

It would seem that Mr. Heughan (Journal, March 1954) has missed the basic design criterion of drag exerted for a given weight (and bulk) penalty. No mention is made of this fundamental point in the choice of a device for the reduction of the landing run of an aircraft. The choice of comparison of the “Wake brake” with a 7 ft. brake parachute has therefore been made somewhat arbitrarily. Brown does not state that “the usual size of a parachute used for braking an aeroplane is 7 ft.”; on page 271 of the reference concerned (“Parachutes,” Sir Isaac Pitman, 1951), a case for “a particular aircraft” was quoted as “ using a 7 ft. parachute.”
Some Notes on Aircraft Possibilities
Authors: Barnwell F. S.
Published: August 2016

These notes are an attempt to examine what may be achieved in the way of performance, with existing materials and knowledge of aerodynamic engineering.

No claim is made for novelty, either in the data used or in the methods of working from such data to obtain the results arrived at.

Only the simplest engineering mathematics are employed so these results cannot claim academic accuracy, in fact they are most probably considerably inaccurate. But though inaccurate absolutely, the results should be accurate enough relatively for comparative purposes.

Full details of the methods employed are given in the various Appendices. This appears advisable, as it should make quite clear how the results are obtained and leaves it open for anyone to work out further examples by the same methods or to modify the methods themselves.
Formulæ and Methods of Calculation of the Strength of Plate and Shell Structures in Aeroplane Construction
Authors: Heck O. S. , Ebner H.
Published: August 2016

The object of the present report is to make a general survey of the simple formulas and methods of calculation for the determination of the strength of thin-walled structures (plate and shell structures) which are increasing in importance in aeroplane construction, and to facilitate the study of original papers by adding a detailed list of relevant literature. an essential characteristic of the sheet metal covered structures in question is, that the metal skin in addition to the stiffening elements participates in the transmission of force. structures in which the metal sheet serves merely as a covering but which is not loaded in accordance with its strength, do not come within the scope of the present considerations. non-stiffened and stiffened plates and shells, mostly of very small wall-thickness (about 0.5 to 1.2 mm.) may be regarded as structural elements in plate and shell structures (especially shell fuselages, “ monocoques ” and wings).
Notes on the Strength of Stressed Skin Fuselages
Authors: Wallace G. F.
Published: August 2016

With the growing popularity of the stressed skin or monocoque fuselage it is thought that the following notes may be of interest. There are many advantages in using stressed skin construction, but one reason against it in the past has been the difficulty in accurately calculating the strength of such structures. Sufficient information has now been accumulated, however, mainly from American sources, to enable the designer to obtain a fair idea of the strength of stressed skin structures, although the stresses occurring under any system of loads cannot be calculated at present with the same certainty as for the conventional braced structure. In the braced frame fuselage the loads are taken by struts and tie rods in tension and compression, but in the stressed skin fuselage they are taken as bending and shear loads in the skin. Once the ultimate tension and compression stresses are known for the material used, the strength of the struts and tie-rods for any system of braced structures is easily calculated. In the stressed skin structure, however, the ultimate stresses for the material are never realised over the whole structure, as failure invariably occurs through local buckling of the skin. The question is further complicated by the fact that the stress at which local failure will occur in sections built of thin plate varies with the design of the section, and two sections having the same area and same moment of inertia would not necessarily develop the same stress in bending.
Monocoque Construction
Authors: Gerard I. J.
Published: August 2016

The general idea of making aircraft of single-shell or monocoque construction is not new. In the middle ages, the great English philosopher and man of science, Roger Bacon, “conceived of a large hollow globe made of very thin metal and filled with ethereal air or liquid fire, which would float on the atmosphere like a ship on water,” and ever since the inception of the aeroplane, suggestions have been made to construct aircraft wings and fuselages in the form of shells like those of crabs, lobsters or other popular crustacea.

There is at present, a marked trend in aeroplane construction towards the increasing use of metal covering both for wings and fuselages. The water loads on the hulls and floats of various aircraft have always necessitated the use of a robust skin, and although at first wood was commonly used, this was at an early stage of development, replaced by metal.
Trend of Air-Cooled Aero Engines–The Next Five Years
Authors: Fedden A.H.R.
Published: August 2016

In July, 1935, I had the honour of reading a paper before a joint conference of the Royal Aeronautical Society and the Society of British Aircraft Constructors, entitled, “ Future Research on Air-Cooled Aero Engines.” Much water has flowed under the bridges since that date, and we have entered on a period of intensive activity and development in aeronautical matters not fully envisaged 18 months ago.

A number of the suggestions put forward in my previous paper, as being suitable subject matter for research or investigation, have been, or are in course of being, investigated by various Government departments, or interested firms in this country, so that, when I received an invitation from the Royal Aeronautical Society to read another paper during the present Session, I thought it might prove useful to endeavour to write an addendum to the original paper, and try to outline the trend of a future air-cooled power plant for aircraft which would be built during the next five years, it being presumed that these engines would be designed as a result of the experimental work which had already been completed, or is being carried out at the present time, and with the object of meeting the more searching requirements demanded by this increased activity.
Some Notes on Vibration Analysis
Authors: Manley R. J.
Published: August 2016

The general recognition of the importance of vibration study, as a specialised branch of engineering science, is clearly reflected in the fact that each year sees the publication of a great number of papers on all aspects of vibration theory and practice. The theoretical papers most commonly describe new methods of analysis and calculation, and it is becoming increasingly difficult for the general engineer, who has neither the time nor the inclination to follow in great detail the development of all the specialised subjects, of which vibration study is only one, to retain in his mind a clear picture of the general strategy applicable to the attack on vibration problems, and to fit into this strategical scheme the tactical operations represented by the new methods.
The Gyroplane
Authors: Breguet Louis
Published: August 2016

I ought first of all to define what a gyroplane is.

A gyroplane belongs to the helicopter family, aircraft which, as their name indicates, have wings in the form of airscrews.

In effect a helicopter consists of large airscrews, with axes nearly vertical and set in rotation by the action of a motor; the reaction of the air on the blades provides the necessary lift to enable the machine to rise vertically, without forward speed.

I will recall that in order to obtain sustentation without forward speed many suggestions have been made for giving to wings a movement which would produce lift.
Ethyl
Authors: Banks F. R.
Published: August 2016

This paper is an endeavour to present, to the members of this Society and others, as complete information as possible on the subject of a much discussed anti-knock material and to try and dispel any misconceptions which some may still have regarding the use and behaviour of ethyl.

The development of the modern aviation engine has made rapid strides during the last two or three years. The very rapidity of this development, however, has brought an exceedingly important fact home to the engine manufacturers; this is, the influence of the fuel in governing engine performance and reliability.
An Echo of the 1868 Exhibition
Authors: Manning W. O.
Published: August 2016

An occasional glance into the past is often of interest. The following notes refer to an event which was one of the principal landmarks in the history of aeronautics, and which attracted much interest abroad, especially in France. It is hardly necessary to remind the reader that the Aeronautical Society of Great Britain subsequently referred to, is now the Royal Aeronautical Society.

The year 1868 was a year of mark in aeronautics, for it was then that the Aeronautical Society of Great Britain held the first Aero Exhibition in the Crystal Palace.
Ice Formation in Carburettors
Authors: Clothier W.C.
Published: August 2016

From time to time w.e hear of mysterious engine failures, sometimes resulting in forced landings, in which the engine is reported to have gradually lost power until it was ticking over or had cut out completely. This may have been accompanied by sticking of the throttle, so that the pilot was unable to control his engine, and by rough running. Full power is usually recovered at lower altitudes or after landing, and when the engine is run up no defects can be discovered. At certain times of the year similar symptoms have been observed in the case of engines running on the test bed.
Speed and the Economics of Air Transport
Authors: Green F. M.
Published: August 2016

No one denies that speed is an essential to air travel. It seemed curious to me that air liners were operating at speeds varying from 100 to 150 miles an hour, and some months ago I set out to find a logical basis for determining the most economical speed of flight. I did not expect to arrive at an exact solution; but, rather to my surprise, I satisfied myself that I could give a general answer to most of the problems that interested me. I ventured to submit my calculations in a short memorandum to the Aeronautical Research Committee, and I had the privilege of meeting a sub-committee with whom I discussed my ideas. It was suggested that some further calculations on the same lines would be of interest, and it was proposed by Mr. Tizard, the Chairman of the main committee, that I should send a communication on the subject to the Aeronautical Society. The paper that I am reading to-night is the result of this suggestion.
Causes of Detonation in Petrol and Diesel Engines
Authors: Boerlage G. D. , Van Dyck W. J. D.
Published: August 2016

Many types of detonation may be distinguished, and the causes are to be found in the engines as well as in the fuels. Obviously one single cause would not be expected to be found, but, on the contrary, quite a number of properties which will be more or less of influence under different engine conditions. These may differ widely, yet there is more unity in the multitude of causes of detonation than might be expected, and this the authors will endeavour to illustrate. They must apologise for mentioning many well-known, in addition to new, views, but it is necessary to do this for the general exposition of the material.

Two principal types of engines should be considered to-day :–

(1)

That in which the fuel is added to the air at the end of compression (in air compressing or Diesel engines), and

(2)

That in which the fuel is added to the air before compression (mixture compressing, e.g., petrol engines).

Most methods of increasing the output of petrol engines seem to attract the “ demon of knocking ” ; the reverse is true for Diesel engines, which is hopeful for their future development.
Comparison of Aircraft
Authors: Moffett R. J.
Published: August 2016

Many “figures of merit” for the comparison of aircraft have been advanced at various times, but in those cases where the basis of comparison has been logical no consideration has been given to first cost, while in those cases where money cost is included, serious objections can be raised to the value of the comparison made.
The Design of Multispar Wings
Authors: Billewicz Witold
Published: August 2016

Before the publication of the results of my original work connected with experimental researches in the Laboratory of the Polytechnical Institute of Warsaw (where I had the help of Prof. Huber and the collaboration of Mr. Kurowski and Mr. Maksymowicz), I want to give here some reproduction of the paper of Mr. W. F. Kisielew in “ Technica Vozdushnogo Flota,” No. 1, 1936, on the design of multispar wings. The results obtained here are very different from those obtained in the above article.

The methods of calculation of the stresses are well-known for monospar and two-spar cantilever wings (compare series of articles in the Reports of I.B.T.L.— Institute of Research for Aeronautics in Warsaw), but present-day methods of construction require more and more attention to be paid to multispar wings as described in this paper.
Wing-Beats – II
Authors: Batten J. D.
Published: August 2016

In my article Wing-Beats, which appeared in this Journal, in the issue of October, 1930, I recorded a series of experiments demonstrating the strength and lightness of a spring formed by twisting skeins of natural silk.

My hope is that silk torses of this kind will fulfil, in human flight, the postural function of a bird's pectoral muscles, leaving to human effort the phasic function of these muscles, that is to say, the activity induced by rapid nerve impulses from the brain.

The ratio that may subsist between these two functions cannot, I think, be determined otherwise than by full-scale flight experiments, but the experiments already recorded give reasonable ground for the belief that the requisite human phasic output will be small in relation to the total weight movement.
The Thurston Rotor Cowl for Air-Cooled Engines
Authors: Thurston A. P.
Published: August 2016

One of the main problems in connection with the development of air-cooled engines appears to consist in securing adequate cooling without increasing the head resistance above that of corresponding water-cooled engines.

This problem particularly applies to large air-cooled engines which are limited in size by cooling difficulties. Air-cooled engines for windmill planes and helicopters for alternate slow and fast flying present a further problem, because such aircraft engines will be required to develop maximum horse-power when the speed of translation is lowest.

The airflow over the nose of a bulky body, such as that of an aeroplane, diverges radially in every direction from its axis. Such radial flow tends to overshoot laterally, at its core, the periphery of the engine or other obstruction and so depart from the contour thereof, with the result that a considerable turbulence is set up. Such turbulence has also the undesirable effect of causing a reversal of the pressure gradients, and a corresponding reversed or forward flow of air, in the boundary layer behind the engine, thereby creating a ” dead “ area or areas and so considerably reducing the cooling effect of the general air flow and increasing the turbulence.
Safety Devices in Wings of Birds
Authors: Graham R. R.
Published: August 2016

A noticeable peculiarity in the flight of a certain number of birds is the way their wing-tip feathers separate, both in flapping and in gliding flight. So wide do the gaps between the feathers become, at times, that the outer parts of the wings take on the appearance of hands with their fingers spread out. One's first thought about the matter is that there is probably nothing in it; that the feathers separate simply because they are feathers, and, as such, cannot help themselves; but, on investigation, this turns out to be one of the most interesting of the many aspects of the flight of birds; interesting, not only because it brings to light the infinite care and cunning that have been bestowed on the construction of their wings, but also because it demonstrates the possibility of applying some of the lessons that birds can teach us, to the design of flying machines—gliders in particular. When considering such questions we should always humbly remember that birds are the outcome of the law of the survival of the fittest through countless ages of flying, while we have been at it only for about thirty years.