bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Problems of the Stability and Control of Large Aircraft
Authors: Lyons D. J.
Published: August 2016

In the Realm of stability and control, we are at present travelling headlong into a region of new problems. Besides tidying up the outstanding items on the types of aircraft we are used to seeing flying about to-day, a not inconsiderable task when one considers the troubles we encounter when we undertake the design of a new so-called “conventional” aeroplane, we have to tackle two major lines of research and development. First, the peculiar problems associated with the stability and control of aircraft of large size, both military and civil, into which difficulties associated with high Mach numbers intrude themselves but little; and secondly, the even more extensive problems associated with the stability and control of aircraft, both large and small, which are to fly at very high Mach numbers, not only at their design cruising and diving speeds, but also in the extremely important slow speed conditions. Mr. M. B. Morgan of the R.A.E. has dealt with some aspects of the second series of problems, so I propose to concentrate on some of the problems involved in the first series, that is those primarily associated with the increase of aircraft size.
Aircraft Servicing
Authors: Norman J. , Wilkinson S. F.
Published: August 2016

The method of achieving efficient and economical servicing with the maximum rate of utilisation of aircraft, is a problem which always confronts the aircraft operator, either a private owner flying his modest machine or a national airline with a variety of large and expensive aircraft. From the point of view of safety, their problems are the same.

Efficient servicing is closely related to safety in so far as the airworthiness aspect is concerned and, under present servicing methods, the direct cost of providing this aspect of safety may well amount to some 20 per cent, of operating costs; to this must be added the delays inseparable from major maintenance work which can reduce earning capacity as a result of the time taken to rectify defects. Invariably the cost to the private owner is higher than he had expected and, unless his aircraft is maintained by a competent servicing organisation, it can be subjected to frequent bouts of unserviceability—usually when he needs it most.
The Design of Static and Pitot Static Tubes Jor Subsonic Speeds
Authors: Kettle D. J.
Published: August 2016

The design of the static and pitot static tubes which are still in common use—such as the National Physical Laboratory standard head or the Prandtl tube, dates back some forty years (see Ref. 1). Before these tubes can be used it is necessary to calibrate them, using a replica of the instrument which is commonly regarded as the standard. This procedure assumes a perfect replica. Furthermore, the shape of the instrument head used hitherto (conical or hemispherical) is known to be aerodynamically poor and, as a consequence, the calibration factor varies unpredictably with wind speed, stream turbulence and Mach number.
The Design and Work of the Farnborough High Speed Tunnel
Authors: Thom A. , Perring W. G. A.
Published: August 2016

The importance of the effects of compressibility on the performance and behaviour of high speed aircraft has been appreciated for a great many years, but in this country it was not until 1937 that serious attention was given to the design of a wind tunnel that would enable the study of compressibility to be undertaken by tests on models of reasonable scale. Prior to 1937 the work which had gone on had established the characteristics of a few aerofoils and simple shapes; at Farnborough the work mainly related to the testing of high tip speed propellers, while at the National Physical Laboratory tests had been made of a two-dimensional character on aerofoils, these tests being made in a small wind tunnel driven on the injector principle, by air discharged from a high pressure reservoir.
The Practical Use of Radio as a Direct Aid to the Landing Approach in Conditions of Low Visibility
Authors: Blucke R. S.
Published: August 2016

The problem of landing an aeroplane under conditions of low visibility has
been a subject for speculation for the last twenty years, but it is only within
the last ten years that it has been given any serious practical attention. This
practical attention has been forced by the necessity for aircraft to maintain
schedule regardless of weather conditions in competition with other forms of
transport.

Although certain schemes involving radio were amongst the earliest proposals
for a solution of the problem, the first practical work appears to have been
concerned with methods of a more mechanical or optical nature, including a
proposal to deposit the fog by high tension discharge.
Piloting Commercial Aircraft
Authors: Brackley H. G.
Published: August 2016

This is the first time I have been given the honour of reading a paper before the Royal Aeronautical Society, and I propose to give you a brief review of the progress made in commercial air pilotage and some of the problems the presentday captain of aircraft has to tackle on every day all-the-year-round flying in Europe and on the Empire routes to Africa, India and Australia.

It is perhaps desirable at the outset to see how commercial flying differs from military and private flying.

In the first place commercial routes are fixed and aircraft operate to schedule with many ground aids, compared with R.A.F. operations which of necessity have to be carried out without the assistance available on regular organised routes.

In commercial flying, formation and any flying involving steep turns and sudden manoeuvres must be avoided. Passengers’ comfort must be studied. Flights are of longer duration, and the commercial pilot flies many more hours during the year than does a military pilot.
Pin-Jointed Struts
Authors: Sumanadasa L. H.
Published: August 2016

Simplified method of solution of the equation,

1

where p = the permissible stress.

py = proof stress.

d = external diameter of strut.

k = radius of gyration.

l = length of strut.

δ = eccentricity.

E = Young's modulus of elasticity.

This method is mainly developed in order to reduce the time taken to work out a series of curves of permissible stress against (l/k). The graphical methods have so far been elaborate and no definite accuracy can be maintained.
Some Sailplane Design Data and Information from German Sources
Authors: Shenstone B. S.
Published: August 2016

Squadron Leader Buxton has pointed out the lack of basic design data for sailplanes available in English. To alleviate this condition to a certain extent, the following data are presented. All the data arc from German sources and the Society is indebted to Alexander Lippisch, A.F.R.Ae.S., and to the Deutsche Forschungsanstalt fuer Segelflug for much of the information.
Cooling Problems, with Particular Reference to the Work of the 24ft. R.A.E. Tunnel
Authors: Douglas G. P.
Published: August 2016

Cooling problems have recently been occupying a considerable portion of the time of the Aerodynamics Department at the Royal Aircraft Establishment. The work had hitherto been of a theoretical nature combined with tests in the small tunnels. The new 24ft. tunnel has provided us with a very valuable piece of apparatus to deal with the problem. The work is proceeding and is still incomplete, but we are beginning to have a clear idea of the principles involved. In this lecture I propose to describe briefly the tunnel and its working and the work we have been doing in it. The lecture is given by permission of the Director of Scientific Research, Air Ministry, but the views expressed represent only my own opinions.
The Prevention of Ice Accretion
Authors: Lockspeiser B.
Published: August 2016

Flying, in common with all means of transport, is affected by adverse weather conditions, but the necessity of aeroplanes to maintain flying speed introduces a major difficulty of its own. The older forms of transport are able, in the last resort, to evade their difficulties by coming to a dead stop. An aeroplane must, literally, fly in the face of its difficulties. It must fly blind in clouds and perhaps land in fog. Over and above this, flight under certain meteorological conditions introduces a danger unique to aircraft. Ice may deposit at all leading edges and grow to windward, at critical regions of the relative airflow, in shapes which increase drag and seriously decrease lift. The accumulated ice adds to the weight. Unsymmetrical ice deposits on the airscrew blades cause dangerous engine vibrations which can only be kept in check, if at all, by throttling back at the expense of thrust. Venturis and pressure head orifices become blocked with ice, rendering the instruments they serve useless. External controls may become jammed. In short, many adverse factors to prevent flight may be brought into play simultaneously by the mere fact that particular meteorological conditions have been encountered.
The Domain of the Helicopter
Authors: Hafner Raoul
Published: August 2016

When accepting the invitation to present the Seventh Louis Blèriot Memorial lecture, the author was deeply conscious not only of the honour which was bestowed upon him by this invitation but, in an equal measure, of the responsibility which attached to it.

For the first time one of the eminent memorial lectures is devoted to the rotating wing; the helicopter has been raised to the level of discussion of the great aeronautical papers.

The natural impulse of the gentler sex when faced with a great occasion is invariably: “how shall one dress?” To the author, a somewhat similar problem became manifest: how can the helicopter, this new-comer, best be “ dressed?” How should it be presented, so as to make not only a good impression but also a full and, above all, a true impression?
Henson's “Aerial Steam Carriage,” 1843
Authors: Hodgson J. E.
Published: August 2016

It is just one hundred years ago, towards the end of March, 1843, that the invention or design of the first power-driven aeroplane, Henson's so-called “Aerial Steam Carriage,” was made public to the world at large. The centenary marks an important step in the history of heavier-than-air flight, and in view of the development arrived at in the aeroplane of to-day—its great size, immense power, long range, and astonishing speed—the event assumes, in retrospect, a greater interest and significance than has been hitherto accorded to it. It is fitting, therefore—the more so in that the ‘inventor’ was an Englishman—that this notable occasion should not be allowed to pass unnoticed in the pages of the Royal Aeronautical Society's Journal. There is, moreover, the additional reason that the Society can claim an indirect connection with Henson's project, in as much as John Stringfellow, who was closely associated with Henson in their joint struggles to produce a model flying-machine, was one of the Society's most active and enthusiastic members in its early years.
A Method for the Photographic Recording of Take-off and Landing Performanc
Authors: Douglas J. B. , Mills J. B.
Published: August 2016

This method has been designed to give all necessary performance data, concerned with the take-off and landing of aircraft, in a cheap and efficient manner. The complete path of the machine from the start of the take-off run to beyond the screen is recorded on a single photograph and from it the reduction of the data is done readily and simply. In the case of a take-off the data obtainable is as follows :

(a)

Take-off run.

(b)

Nature and length of the transition.

(c)

Height at any screen.

(d)

Distance, velocity and acceleration at any point from the start.

(e)

Angle of climb.

(f)

Rate of climb.

(g)

Any irregularities in the flight path.

Similar data can be obtained in the case of a landing. Any information may be extracted independently and the photographic negative filed for future reference.

The camera used is simple and inexpensive, both in construction and subsequent use. Four persons at present form the total ground staff and with an improved camera now under construction one of these is eliminated.

The accuracy obtainable with the present apparatus is sufficient to fix the position of the aircraft to within ± 2 feet. Once the initial work has been carried out on any aerodrome, future use of this method has been found to be simple, quick and sufficiently accurate for all normal requirements.
Limiting Factors in Single Stage Centrifugal Superchargers for Aero Engines
Authors: Kollman K.
Published: August 2016

To-day all altitudes up to, and including, the stratosphere are within the scope of aviation. The engines must therefore be provided with highly developed superchargers so as to obtain high performance even at these altitudes. The single or multi-stage superchargers necessary to accomplish this become an integral part of the engine and exercise a distinct influence on its general construction.

In many types of engine the supercharger is built on to the accessory drive end, that is the rear of the engine, so that the supercharger shaft lies co-axially or parallel with the crankshaft.
Delays in Landing of Air Traffic
Authors: Pearcey T.
Published: August 2016

A recent paper gave an elementary analysis of the effect of control procedures on the flow of air traffic. It was shown that the average delay experienced by aircraft landing at an airport increases rapidly as the arrival rate approaches the maximum handling capacity of the airport. It is the object of the present paper to give a more rigorous treatment of the problem and to derive the distribution of delays under different traffic conditions.

The maximum handling capacity of an airport is the greatest rate at which aircraft can enter the airport with absolute safety. It is determined by the safe minimum separation between successive landings. An aircraft arriving in the central zone with less than the safe minimum separation is withheld from landing until the minimum interval has elapsed.

In the following it is generally assumed that aircraft cross the boundaries of the control zone from random directions with random separations, the mean arrival rate being constant. Aircraft which follow their predecessors too closely are assumed to be delayed for a minimum period so that none lands with an interval less than the safe minimum. As a simplification it is assumed that no aircraft takes off from the airport.
Wireless and its Application to Commercial Aviation
Authors: Furnival J. M.
Published: August 2016

Already wireless is playing an extremely important part in connection with the smooth and safe operation of the commercial aviation services of to-day and it is evident that the present-day trend is to place more and more reliance upon wireless aids for the achievements of that regularity of service in all weathers, which is looked upon as necessary for the ultimate success of truly commercial aviation.

It seems therefore desirable to review at the present juncture the functioning of wireless communication and direction finding systems as used by the commercial air services; to consider some of the problems with which designers and operators are faced, and to bring to light the limitations and possibilities of this medium of communication and direction finding, both in respect to present and future requirements.
Surface Films and Lubrication
Authors: Pye D. R.
Published: August 2016

When the Council of the Society did me the honour to invite me to deliver the Wilbur Wright Lecture I found myself in a dilemma. Many of those whose lives are concerned with engineering or with scientific research must feel, as I do, that after a certain stage they cease to be quite the real thing. The realities of the workshop give place to a daily round of files, reports and estimates, and the laboratory knows one only as a visitor.

When a man has entered upon this ink-stained path and is invited to give a public lecture, there are only two things he can do, except refuse. He must either plagiarise or generalise. Of the two, on grounds of morality, I prefer the latter; but it has the disadvantage common to most moral alternatives, it is much the more difficult. For myself, too, there is a further complication, because the field in which I might feel qualified to generalise would be on some subject relating to engines and their development.
Mixture Strength in Petrol Engines Continuously Controlled by Electric Exhaust Gas Analysers
Authors: Boerlage G. D. , Peletier L. A.
Published: August 2016

During the last few years continuous indicating electric exhaust gas analysers have been coming into use more and more for controlling the strength of the fuel/air mixture which the carburettor feeds into the engine.

These instruments have already been described in a publication (vide List of References (i)), but since they are of growing interest, especially for aviation, some further research as to their merits and shortcomings seems to be indicated.

Therefore tests have been run with an aircraft type of instrument (the “ Cambridge (N.Y.) Aero Mixture Indicator ”) and an automobile type of instrument (the “ Lantz Phelps Motor Fuel Combustion Tester ” ).
Engineering Problems in Aircraft Operation at High Altitudes
Authors: Johnson R. E. , Gagg R. F.
Published: August 2016

The authors review the capabilities of the typical modern airplane for high-altitude operation and present the restrictions of the power plant of the modern airplane which prevent it from delivering its normal output at high altitudes. The paper also discusses the improvements in the aerodynamic characteristics of the airplane as well as changes in the power-plant design and the progress achieved in cruising operation at high altitudes within the limitations imposed by passenger comfort and safety. The authors evaluate further possible gains which may result from an extension of this trend, and examine the engineering problems involved in both the airplane and the engine.
Some Considerations on the Reaction of Wind Upon Sails
Authors: Moore-Brabazon J. T. C.
Published: August 2016

The study of the problems connected with a successful racing sailing boat, like Gaul, can be divided into three parts. There is first of all the general configuration of the hull upon which lately much study has been directed. Anybody interested in this should look up the article, “Model Tests of Sailing Yachts,” by Kenneth S. M. Davidson, Director, Experimental Towing Tank, Stevens Institute of Technology, New Jersey, appearing in the August issue of “The Rudder,” in which it will be noted model hulls are pulled through the tank at an angle of heel, and with an angle of drift.
Profile Drag
Authors: Melvill Jones B.
Published: August 2016

Thanks to the pioneer work of Lanchester and Prandtl everyone seriously interested in aeronautics has nowadays sufficiently clear ideas about the power and the associated drag which are essential for the support of an aeroplane in flight. This induced drag, as it is now called, can be calculated with an accuracy which is ample for most practical purposes, and even with the very clean aeroplanes of the present time it contributes, at and above cruising speed, a minor part only to the total drag. We are equally familiar with the idea that the remainder of the drag—the drag involved in getting the aeroplane through the air as opposed to holding it up—can be reduced, by careful design, nearly to the mere skin-friction of the air rubbing over exposed surfaces; the reason being, of course, that the pressures on the surface of a well streamlined aeroplane are so distributed that their horizontal components form an almost completely balanced system.
Magnesium Alloys
Authors: Desch C. H.
Published: August 2016

An account is given of developments during the last three years in the production of light magnesium alloys suitable for aircraft construction. The heat-treatment of castings and the hardening by ageing of forged alloys are considered as well as the copditions affecting forging at various temperatures. The connection between these properties and the crystalline structure of magnesium is discussed.
An Analysis of the Flight of an Aeroplane, when directed by means of a Radio Beacon, for all possible values of Wind Velocity
Authors: Greatrex F. B.
Published: August 2016

In these days of long distance flights across large stretches of ocean aeroplanes will make considerable use of radio direction-finding apparatus, enabling them to keep their course on to a transmitting station at their goal. Over the Atlantic, for example, a series of beacons all the way across would be quite impracticable. The following is an analysis of the course flown by an aeroplane under these circumstances, showing also the increase in flying time over that on a compass course, and also the maximum deviation from the compass course.
Aeroplane Stability and the Automatic Pilot
Authors: Meredith F. W. , Cooke P. A.
Published: August 2016

Automatic pilots are gradually coming into general use all over the world. Their usefulness has now been proved over a period of about ten years in this country and over a somewhat shorter period in other countries, notably the U.S.A., where the Sperry Automatic Pilot has been evolved after many years of pioneering work. Early pioneering work had also been done in this country by Mr. T. W. K. Clarke before the war.

The world's patent literature shows that inventors have been interested in the problem for at least a quarter of a century. Indeed, this was inevitable since the automatic helmsman or “Iron Mike” for marine craft was a proved success and the vagaries of their younger sisters of the air clearly indicated the need for firmer handling in their case also.
Protection of Aircraft Against Ice
Authors: Hardy J. K.
Published: August 2016

A meeting of the Royal Aeronautical Society was held in the lecture hall of the Institution of Civil Engineers at Great George Street, Westminster, London, S.W.1, on Thursday 5th December 1946, at which a paper by Mr. J. K. Hardy on “ The Protection of Aircraft Against Ice,” was presented and discussed. In the Chair, the President, Sir Frederick Handley Page, C.B.E.
On the Nature and Conditioning of Least Work Equations in Structures
Authors: Morris J.
Published: August 2016

In this paper an explanation is furnished as to why linear simultaneous equations arising in structural problems are, in certain circumstances, sensitive or “ill-conditioned,” and an indication is given concerning the physical significance of this sensitivity. Means are also discussed whereby difficulties of this kind may be overcome.
Design for Maintenance
Authors: Bowden T. E. G.
Published: August 2016

The title of this paper is the result of practical experience in the maintenance of aircraft, combined with a view to trying to improve the design standard in future aircraft. In the past, engineers, especially aircraft engineers, have put up with a considerable amount of poor maintenance design and have gone on improvising time and time again as the only solution to their problems. As a result of this improvisation it is probable that those concerned with the actual design do not realise many of the difficulties experienced in the maintenance of their aerodynamically efficient aircraft.
Airscrew Blade Vibration
Authors: Carter B.C.
Published: August 2016

During development of solid metal airscrews in the U.S.A. many vibration failures occurred and various investigations have been made there and elsewhere with a view to overcoming such troubles. The problem is to avoid airscrew failures while keeping weight as low as possible; its solution involves mathematical analysis, further development of experimental methods, and investigations in relation to particular combinations of engine and airscrew.
The Lotz Method for Calculating the Aerodynamic Characteristics of Wings
Authors: Shenstone B. S.
Published: August 2016

The method generally used in England for calculating the aerodynamic characteristics of wings is that suggested by Glauert (1), in which the circulation across the span of the wing is represented by a Fourier series. On account of the form of the series, certain difficulties arise which make the calculation very tedious when more than about four points along the semi-span are considered.
Control Surface and Wing Stability Problems
Authors: Pugsley A. G.
Published: August 2016

This paper seeks to draw from current research work on flutter and related problems results of general design significance; and, avoiding mathematics, endeavours to set these results out in relation to past and present problems.

A preliminary section of the paper indicates the main stability and allied troubles concerned and draws attention to the general similarity between wings and tailplanes in relation to these troubles. The remainder of the paper is then devoted to a discussion of the problems involved in terms of wings and ailerons.

For this purpose a “ stiffness diagram ” is constructed for a typical wing, indicating the relative stiffnesses, etc., required to prevent wing-aileron flutter, wing flutter, aileron reversal, and wing divergence. By means of this diagram the course of recent history in relation to wing-aileron flutter and aileron reversal is illustrated, and attention is then given to present and future tendencies and problems. The current tendency to employ wings of high density—arisingly largely from high wing loadings—is making wing flutter the problem of immediate importance, and ways of avoiding the provision of increased stiffness as usually adopted to prevent this trouble, as well as to prevent aileron reversal and wing divergence, are discussed.

Appendices are given commenting on the variation of wing flutter speed with altitude and on the modern tendency to usa wings of low flexural stiffness.
Power Plant Trends
Authors: Mead George J.
Published: August 2016

Transport aviation is expanding rapidly in America both because of improved business conditions and the excellent record of the transport companies. The new aeroplanes being laid down, both land transports and boats are, on the average, twice the size of their immediate predecessors measured in terms of gross weight. Never before in the history of our industry has there been such a large increase in size in such a short period (Fig. 1). Coupled with the demand for larger aeroplanes is the requirement for decidedly higher cruising speeds. To meet these demands the total thrust horse-power per aeroplane has been materially increased. Operating costs are becoming more and more important due to the competition among air lines, as well as between them and other forms of transportation. The engineer is consequently forced to give serious consideration to utilising the power available in the most efficient manner, as well as to reducing maintenance costs.
High-Speed Flying
Authors: Wimperis H. E.
Published: August 2016

The attainment of the mighty speed of 379 miles an hour by an officer of the Royal Air Force (Flight Lieutenant Stainforth) is fresh in our minds and we honour the pilots, the aircraft builders and the engine constructors who made this possible. We remember also, I hope, the scientific workers, whose investigations afforded the basis on which so much else was built. When one contemplates motion at such speeds as this, one cannot help speculating where such enterprise will lead. The power to move is not new; railways and roadways give abundant evidence of high speed, but motion along them is almost entirely in two dimensions. It is only when the freedom of the air makes three-dimensional motion possible that the problem appears in its greatest and most interesting aspect. In the air there is combined the greatest possible freedom with the highest possible speed, and it is this combination which makes the study of such intense scientific interest. Moreover, the flight path may be greatly curved and that curvature may be in any plane. Great forces may then arise and act upon the aircraft from any side. It is not for nothing that the pilot is strapped into his seat.
Power Installations
Authors: Owner F. M.
Published: August 2016

Never, at any time since the Wright Brothers made their first flight have the means of propulsion exercised a more dominant influence over the shape of aircraft or the shape of things to come, nor can it have been so difficult to forecast the form resulting from that influence. It has been a platitude for some time past to say that aircraft and engine design are mutually interdependent: now it is more than a platitude, it is a fact, and one to which we have not yet grown accustomed.

That power installations can no longer be procured “off the peg” is to-day an article of faith which is generally professed: what is rarer is an appreciation of the implications of this state of affairs. Pursued to its logical conclusion, the implication is that a new aircraft and its means of propulsion should originate in the same brain, and be designed, developed and manufactured under the guidance of that brain.
Flight in Nature and in Science
Authors: Giacomelli R.
Published: August 2016

Due proportions being established, it can be said that the present time, as regards what has been called the “conquest of the air,” is comparable to that extremely remote epoch in which Nature for her part also solved the problem of flight.

Man arrived late in the history of his life at the realisation of locomotion in the air, but Nature also reached the same realisation only in a second stage of the evolution of living forms. The early animal species were all wingless, the development of the wings being the effect of a successive adaptation.

At present the number of fliers is very large.

From calculations of the zoologist Dödering, mentioned by the zoologist Zschokke, together with a large number of interesting data and information about animal flight in a very important book, we know that among 420,000 animal species at present existing at least 260,000 are able to move through air. As is seen, flight is a faculty widespread in Nature; from the figures some 62 per cent, of the species living to-day is adapted to aerial locomotion. If from these calculations we exclude water creatures, which give a small contribution of fliers (and moreover of a very poor quality), the ratio of the flying to the nonflying species rises to 75 per cent.
Air Flow
Authors: Farren W. S.
Published: August 2016

Aircraft engineering has been described as “ordinary engineering made more difficult.” Probably most of you will agree that our difficulties are often greater than those that confront other branches of the engineering profession, and that the chief source of them is our inability to forecast with entire confidence what air will do under any given circumstances. Our position in this matter is much better than it was, for instance, at the end of the war. During the last thirteen years we have seen the theories associated with the name of Professor Prandtl receive general acceptance, with a profound effect upon our attitude towards some of the most important practical problems of air-flow with which we have to deal, namely, those associated with the production of lift. The boundary layer, then little more than a scientific curiosity, has become a matter of common concern. It achieved a striking practical success in the rationalisation of the international tests of airship models, which led to a marked advance in our attitude towards the whole problem of scale effect. But in many respects we are still greatly hampered. In so far as there has been any advance in the pure hydrodynamical theory of the flow of viscous fluids, it is hardly too much to say that its practical effect has been negligible. What then are we to do?
The Method of “Least Work” and the Stressing of Aeroplane Structures
Authors: Evans F. G.
Published: August 2016

In aeronautical engineering the strength-weight ratio is so important, apart from the fact that the consequences of structural failure are generally more disastrous, that it becomes essential to investigate the loads and stresses in the various parts of the structures far more accurately and in much greater detail in order that smaller factors of safety may be used.

It is often possible, in the case of structures of a low order of redundancy which have to be designed to meet several different systems of loading, to select by inspection those members which may be considered to be the redundant ones, the elimination of which would result in an increase of the design loads in most of the remaining members. If the members are designed to such increased loads many members of the structure will be overstrong and unnecessarily heavy. The excess of strength of the various members of the complete redundant structure will almost certainly differ, so that the weight of the whole will be increased above the essential in a greater proportion than the strength.
The Behaviour of Fluids in Turbulent Motion
Authors: Fage A.
Published: August 2016

The internal motjon of a fluid assumes one or other of two distinct forms; either the elements follow one another in a direct and simple manner, or else they wander about in erratic paths as they progress downstream. In the first kind of motion, called “ regular ” or “ streamline,” the components of the velocity at any selected point are either constant, or vary in a definite manner directly related to the boundary motions. In the second, known as “ turbulent,” these components continually change in an irregular way, which cannot apparently be connected with the regular boundary motions.
Sir George Cayley the Founder of British Aeronautical Science
Authors: Hodgson J. E.
Published: August 2016

It is, I suppose, known to most of those present in this lecture hall that the Royal Aeronautical Society was founded in 1866–to be exact the first preliminary meeting was held, under the chairmanship of the Duke of Argyll, on January 12th, though the first meeting of members did not take place until the 27th of June following. It is, therefore, within a few days of 70 years ago that the Society came into being. That is a full and honourable age, and with it goes the distinction–in which we are entitled to take some pride–of being the oldest Aeronautical Society in the world. The anniversary may not arouse the enthusiasm usually associated with the more youthful glamour of a silver or a diamond jubilee. On the other hand it denotes another decade of progress in the growth of aeronautical science, and of even more marked developments in the application of that science, on which grounds alone it deserves passing notice.
Some Factors Affecting the Range of Aircraft with Special Reference to Height
Authors: Woodward Nutt A. E. , Scroggs A. F.
Published: August 2016

From that memorable day in December, 1903, when Orville Wright made the first power driven flight, aeronautical engineers have directed continuous efforts towards improving the range of aircraft. The distance covered on that first flight was about 120 yards. At the present time the record for distance flown in a straight line stands at 5,012 miles, and as for duration, some unfortunate Americans recently succeeded in staying in the air for nearly 27 days and nights without landing. This latter record has little value beyond that of an endurance test of the engine, and possibly the physiological effects on the occupants of the aircraft. The long distance record, however, has a direct influence upon the design of both military and commercial aircraft.
Wing Construction
Authors: Stieger H. J.
Published: August 2016

“Weight” is the key to everything that matters in aircraft construction. It is of paramount importance to performance, comfort and safety. Incidentally, it is also many a designer's excuse for any shortcoming on his machine.

Analysing the weight figures for an aircraft, one can classify them into three groups:—

1.

Weights over which the designer has no influence.—Namely, engines and accessories, airscrews, instruments, wheels and brakes, etc. This group represents about 35 per cent. of the empty weight of a normal commercial machine.

2.

Weights over which the designer has a limited influence.—Namely, fuel tanks and pipes, cowlings, engine controls, cabin equipment, upholstery and windows, heating, etc., which represents some 20 per cent. of the empty weight.

3.

Weights within the designer's influence.—Namely, wings, fuselage structure, tail unit, chassis, flying controls, etc., which represent about 45 per cent. of the empty weight.
Transversely Loaded Framework Members
Authors: Hoff N. J.
Published: August 2016

The standard method of strength calculation of a framework is based on the assumption that members are freely pinned together and external forces are applied only at nodes. Actually aircraft fuselage members are stiffly joined and transverse forces are often acting on them at considerable distances from nodes, e.g., weights of crew, instruments and oil, reactions of controls, stabiliser adjusting gear, etc.

The safest method of computing stress in such members is to assume both ends pin—jointed. As they actually are stiffly connected to adjacent members, they are not allowed to twist freely, i.e., the truss exerts moments on the loaded member. The effect of these end moments consists in diminishing deflection andfield moments. The decrease of maximum bending moment may attain nearly 50 per cent.

Since framework members are designed to withstand axial forces only, viz., tension or compression, they are comparatively weak against bending and have to be strengthened appreciably if transverse forces are present.
The Development and Progress of the Aero Engine
Authors: Ricardo H. R.
Published: August 2016

The possibility of sustained flight by heavier-than-air-machiaes was fully recognised during the last century by those who had studied the aerodynamic problems involved and it was realised that its accomplishment awaited only the development of a prime mover of sufficiently light weight.

Of all the known forms of prime mover, the internal combustion engine alone held out any promise of fulfilling the conditions necessary .for sustained flight, namely, light weight not only of the engine itself but also of the fuel it consumes. Early attempts had, however, been made to fly with steam, propulsion and it is of interest to note that the very remarkable and cleverly-designed steam plant employed by Sir Hiram Maxim in 1894 was actually very considerably lighter per h.p., even including the boiler and condenser, than the petrol engine used successfully some nine years later by the Wright Brothers.
The Aerodynamics of Leonardo Da Vinci
Authors: Giacomelli R.
Published: August 2016

Many books on aerodynamics are prefaced by a short historical introduction, in which, after having quoted Aristotle for his ideas on the motion of bodies through the air, and Newton, from whom aerodynamics is admitted to start, the name of Leonardo da Vinci is recorded, pointing out that he was the first to attribute to the resistance of the air the cause of the lift and flight of birds, recognising in the same resistance the possibility of solving the problem of flight.
Wheel Brakes and Undercarriages
Authors: Scott-Hall S.
Published: August 2016

Until recently an aeroplane undercarriage has generally been called upon to serve two purposes only :—

To absorb the energy due to the vertical velocity of the aircraft when landing;

To enable the aircraft to be flown off from, and manoeuvred over, ground which may be very rough or very soft.

To these requirements are now added a third :—

To absorb the energy due to the horizontal velocity of the aircraft by means of wheel brakes.

These three duties must be carried out with the minimum possible weight and head resistance, for the undercarriage must be as self-effacing in flight as it is all-important on the ground.

The problems connected with wheel brakes are very specialised in themselves and have a particular interest at the present time. For this reason it was decided to deal with them first, and later to turn to the more general aspects of undercarriage development.
Range of Aircraft
Authors: Fairey C. R.
Published: August 2016

Range in any given vehicle of transport is generally understood to be the distance that it could travel without requiring to stop for any supplies necessary to maintain its normal performance.

It is, moreover, at least one quality in the aeroplane to which the designer may set a limit to his ambitions. With regard to speed, load carried, and so forth, he faces an endless task, but when range has reached a distance of just over 12,000 miles, equivalent to the greatest distance between any two points on the planet, his task in this respect is presumably at an end and in practice probably much earlier as the distance between which aeroplanes will need to operate will certainly be less than this.
Some Technical Notes on Canadian Aviation
Authors: Hume D. C. M.
Published: August 2016

Before opening my subject let me explicitly impress upon you that any opinions I may be found to have expressed in these notes are purely my own, and not necessarily shared by the Service to which I have the honour to belong, much as I owe them to its inspiration.
Water-Cooled Aero Engines (Six Years' Progress)
Authors: Rowledge A. J.
Published: August 2016

After some thought I have chosen the subject of this paper to enable me to include information gleaned in the last six years of intensive development work at the firm where I am employed, and I think that by this choice I shall be making the most useful contribution towards the production of the ideal engine, safe and efficient, which we all desire.
Slots and the Wings of Birds
Authors: Lachmann G. V.
Published: August 2016

It was a great revelation to me to read Lieut.-Comdr. Graham's study of the “Safety Devices on Wings of Birds,” reprinted in the Journal of the Aeronautical Society of January, 1932. I had always believed that the gaps formed by the tip feathers on a bird's wing were not strictly comparable to slots, because from a superficial observation of birds’ wings, it appeared that the slots were running in the wrong direction, namely, from the top to the lower surface of the wing. Lieut.-Comdr. Graham's outstanding contribution is his discovery of the reason for the emargination of the web of the slot forming wing tip feathers. There can be no doubt that this arrangement is aerodynamically equivalent to a multi-slotted wing.
Some Aspects of the Design of Sea—Going Aircraft
Authors: Gouge A.
Published: August 2016

The subject I have to talk about this evening is one on which many previous papers have been read before this Society, so I am afraid I must ask you not to expect much original material from me. Practically the whole of the material I have gathered together is the result of practical experience, and from this point of view I hope it will prove interesting.

During recent years considerable development has been done and good progress made with both the design and operation of big flying boats.Also, the Schneider Cup races have caused a considerable amount of research work to be done on the development of twin float seaplanes, particularly with regard to taking off the water at very high speeds and also to the air resistance of the floats.

In the last year we have seen the advent of the Dornier Do.X the largest flying boat yet constructed, whose total flying weight approximates to 50 tons.
The Drag Effects of Roughness at High Sub-Critical Speeds
Authors: Young A. D.
Published: August 2016

Measurements were made in the Royal Aircraft Establishment High Speed Tunnel of the drag of a wing with various grades of surface roughness in the form of camouflage paint. The measurements were made for a range, of Reynolds number from about 4.5 × 106 to about 15 × 106 at a constant Mach number of 0.2, and for a range of Mach numbers from 0.2 to about 0.7 at a constant Reynolds number of 4.5 × 106 and to about 0.6 at a constant Reynolds number of 6.0 × 106. It was found that for the range of Mach numbers tested compressibility had no appreciable effect on the drag increase due to roughness (Figs. 2 and 3). Further, the drag effect of each roughness tested was such that an equivalent size of sand roughness Ke, of the type tested by Nikuradse, could be readily associated with it. For each finish tested a number of roughness records were taken by means of a roughness gauge developed by Dr. Tomlinson, of the National Physical Laboratory (Fig. 5).
Siting of Landing Strips for International Aircraft Movements in Great Britain
Authors: Courtenay William
Published: August 2016

Air travel at 600 m.p.h. to 650 m.p.h. in the next decade and the use of multi-seat twin rotor helicopters on internal air routes to help to solve terminal delay problems, bring in their train growing problems of Air Traffic Control. Full use of high speed civil transports and helicopters does not seem practicable within the British Isles unless the problem of the siting of landing strips is reviewed and unless ideas on this subject are recast in the light of growing experience.

To the commercial airline pilot Great Britain is indeed a “tight little island.” It will appear smaller yet when the de Havilland Comet jet air liner operates to time-tables of approximately double the speed of most of the existing schedules of today.
The design and Development of the Helicopter Rotor Testing Tower
Authors: Tayler R. F.
Published: August 2016

From the start of the development of helicopters at the Bristol Aeroplane Company the necessity was appreciated of providing means of testing, independently of the aircraft, rotor hubs and blades. The usual method of testing on the helicopter suffers from several disadvantages, the most important being that proximity of the ground beneath the rotor greatly affects the flow through it and makes such performance figures as can be obtained unrepresentative. Others are the probable inconvenience of having to wait for the completion of the aircraft before rotor-testing can start, the comparative difficulty of instrumentation, and the risk of damage to the aircraft by failure or misbehaviour of the rotor.
Directionality of Wrought Light Alloy Materials
Authors: Baillie I. L. G.
Published: August 2016

The principal materials employed in modern aircraft structures are aluminium-rich alloys which the aircraft manufacturer will normally buy in the semi-finished (cast or wrought) state. Wrought materials fall into the four main classes of tubes, sheets, extrusions, and forgings; eacri of these forms inherently exhibits distinctive mechanical strength characteristics. In this paper the relation of the mechanical properties of medium and high strength wrought light alloy materials to the grain direction, and the implications of this relation in aircraft design, will be discussed.
The Effect of Mean Stress on the Fatigue Strength of Magnesium Alloy ZW2
Authors: Low A. C.
Published: August 2016

The work reported in this Note originally formed part of a comprehensive investigation into the fatigue strength of magnesium alloy ZW2 (2 per cent. zinc, 0·65 per cent. zirconium) in sheet form. The major portion of the programme was eventually cancelled but the tests herein described are sufficiently self-contained to be repotted by themselves. Direct stress fatigue determinations were made on small round test pieces machined from ¾ in. thick plate, at mean stresses of 0, 4,000, 8,000 and 13,000 lb./in.2. Static and rotating bar fatigue tests were also made.