AERONAUTICS.

T? TTPOT? TiUSr <LJI11OF THE

AERONAUTICAL RESEARCHCOMMITTEE

FOR THE YEAR 1922-23

(With APPENDICES).

VOL. I.Aerodynamics (Model and Full Scale),

I v O N D O N :PUBLISHED BY HIS MAJESTY'S STATIONERY OFFICB.

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1924.Pncs {1

CONTENTS.

VOL. I.

Aerodynamics (Model and Full Scale).Page

Members of the Committee ... ... ... ... ... ... viii

Report of the Committee for the year 1922-23

APPENDICES TO THE REPORT.Aerodynamics (General) :—

(i) On the rate of transmission of heat from the walls of anairship passenger car.—By Miss-D. Marshall, B.Sc. ... 47

(i i) The singing of circular and streamline wires.—By E, F.Relf, A.R.C.Sc., and E. Ower, B.Sc., A.C.G.I. ' ... 56

Aerofoils :—(i) On the theory of rectangular and tapered aerofoils.— By

A. Page, A.R.C.Sc, ... ... ... ... ... 60(ii) A method of calculating the characteristics of a tapered

wing.—By H. Glauert, of the R.A.E. Presented bythe Director of Research ,,, ... ... ... 74

(iii) The design of tapered wings.—By W. S. Farren. M.B.E.,M.A. ... ... ... ".. . ... ... ... 81

(iv) An empirical method of predicting the aerodynamicproperties of an aerofoil.—By Alexander Thorn, B.Sc. 101

Model Experiments (Aeroplanes) :—(i) An investigation of die influence of downwash on the

Rotary Derivative Mc.—By L. F. G. Simmons, B.A.,A.R.C.Sc., and K. Ower, B.'Sc., A.C.G.T. ... ... 106

(ii) The Handley Page dotted wing.—By H. Glauert, of theR.A.E. Presented by the Director of Research ... 114

(iii) Tests of four slotted aerofoiK, supplied by Messrs.Handley Page, Ltd.- By F. B. Bradfield, of the R.A.E.Presented by the Director of Research ... ... 121

(iv) Rolling and yawing moments due to roll of model Avrowings, with standard and interplane ailerons andrudder moments for standard and special large rudder.—By F. B. Bradfield and O. E. Simmonds, of theR.A.E. Presented by the Director of Research ... 135

(v) Some suggestions for improving aeroplane control atlow speeds.—By A. Fage, A.R.C.Sc. ... ... ... 147

(vi) Some experiments on a model biplane having slottedwings, with particular reference to the improvementof lateral control at low speeds. - By H. B. Irving,B.Sc., and A. S. Bat son, B.Sc. ... "... ... ... 153

(vii) Biplane investigation with R.A.F. 15 section. Part II.—By VV. L. Cowley, A.R.C.Sc., and L. J. Jones ... 159

(B79S4) Wt.MSW—1173. 375. U «, Qp. 32.

IV

PageAirscrews :—

(i) Experiments with a family of airscrews, including theeffect of tractor and pusher bodies. Part I.—By A.Page, A.R.C.Sc., C. N. H, Lock, B.A., R. G. Howard,B.Sc., and H. Bateman, B.Sc., A.C.G.I,, D.I.C. ... 174

(ii) Experiments with a family of airscrews, including effectof tractor and pusher bodies. Part II.—By A. Fage,A.R.C.Sc., C. N. H. Lock, B.A., H. Bateman, B.Sc.,A.C.G.I., D.I.C., and D. H. Williams, B.Sc. ... ... 240

Wind Channels and Experimental Apparatus :—(i) An attachment to main balances for measuring three

forces and three moments.—By T. Lavender, T. H.Fewster and G. F. Henderson ... ... ... ... 273

(ii) Description of lift, vertical force and drag balances forthe roof of the duplex wind tunnel.—By T. H. Fewster 275

(iii) A continuous rotation balance for the measurement ofLj, at small rates of roll.—By E. F. Relf, A.R.C.Sc.,and T. Lavender ... ... ... ... ... ... 279

(iv) A direction and velocity meter for use in wind tunnelwork, &c.—By T. Lavender ... ... ... ... 281

(v) The No. 2 7-foot wind channel at the Royal AircraftEstablishment.—By The Wind Channel Staff at theR.A.E. Presented by the Director of Research ... 283

Full Scale Experiments (Aeroplanes) :—(i) The manceuvres of inverted flight.—By Squadron Leader

R. M. Hill, M.C., A.F.C., in charge of the ExperimentalFlying Department of the Royal Aircraft Establish-ment. Presented by the Director of Research ... 286

(ii) The eflect upon the control of an aeroplane of carryingload distributed along the planes.—By the Aero-dynamics Staff of the R.A.E. Presented by theDirector of Research ... ... ... ... ... 322

(iii) The comparison of the manoeuvrability of aeroplanes byuse of a cinematograph camera.—By H. A. Francis, ofthe R.A.E. Presented by the Director of Research 339

Airships :—(i) The resistance of a spheroid, with special reference to the

effect, of wires placed around the model in a plane atright angles to the axis.—By R. Jones, M.A., and A. H.Bell ... ... ... ... ... ... ... 337

VOL. II.Materials, Engines, etc.

Strength of Structures :—(i) On the determination of the stresses in braced frame-

works, Part III. The effect of axial loading, torsion,flexure and shear upon a braced tube of any uniformcross section.—By R. V. Southwell ... '... ... 347

(ii) On the determination of the stresses in braced frame-works. Part IV. The effects of axial loading, flexure,torsion and shear upon a tubular framework with taper.—By R. V, Southwell ... .., ... ... ... 362

PageStrength of Structures—continued.

(lii) On Castighano's theorem of least work, and the principleof St. Venant.—By R. V. Southwell ... ... ... 371

(iv) The reduction of the etiectivc value of Young's modulusin flexible compression members.—By A. J. SuttonPippard, M.B.E., D.Sc., Assoc.M.Inst.C.E. ... ... 391

(v) Stresses in a stirt jointed polygonal frame under a systemof parallel loads.— By A. J. Sutton Pippard, M.B.E.,D.Sc., Assoc.M.Inst.C.E. ... ... ... ... 397

(vi) On a method for the direct design of framed structureshaving redundant bracing.—By A. J. Sutton Pippard,M.B.E., D.Sc., Assoc.M.Inst.C.E. ... ... ... 404

Strength of Materials :—(i) Preliminary report on the properties of commercially

pure nickel as a standard material for fatigue investiga-tions.—By G. A. Hankins, A.R.C.Sc. ... ... ... 414

(ii) The mechanics of the Wohlcr rotating bar fatigue test.—By Professor VV. Mason, D.Sc. ... ... ... ... 421

(lii) Report on the influence of calcium and of calcium plussilicon on aluminium.—By J. D. Grogan, B.A., of theMetallurgy Department, National Physical Laboratory 428

(iv) The constitution and age-hardening of alloys of alumin-ium with copper and magnesium and silicon in thesolid state.—By Marie L. V. Gayler, M.Sc., of theMetallurgy Department, N.P.L. ... ... ... 433

(v) The constitution and age-hardening of the ternary alloysof aluminium with magnesium and copper.—By MarieL. V. Gayler, M.Sc,, of the Metallurgy Department,N.P.L. ... ... ... ... ... ... ... 461

(vi) The heat-treatment and mechanical properties of alloysof aluminium with small percentages of copper.—ByI). Hanson, D.Sc., and Marie L. V. Gayler, M.Sc., ofthe Metallurgy Department, N.P.L. ... ... ... 478

(vii) The production and heat treatment of chill castings inan aluminium alloy (" Y ").—Bv \V. Rosenhain, D.Sc.,F.Inst.P., F.R.S./S. L. Archbutt, F.I.C., and S. A. E.Wells, from the National Physical Laboratory ... 490

(viii) The constitution of some alloys of aluminium with copperand nickel.—By Kathleen E. Bingham, M.Sc.,A.Inst.P., and John L. Haughton, D.Sc., F.Inst.P., ofthe Metallurgy Department, N.P.L. ... ... ... 506

(ix) Report on further investigations ot the effect ol sunlighton aeroplane fabric.—By the Chemical Department,R.A.E. Presented by the Director ol Research. Withappendix by Guy Barr, D.Sc. ... ... ... ... 542

Engines :—(i) Air consumption and B.H.P. of Aero engines.—By H.

Moss, M.Sc., A.R.C.Se., D.I.C., Air Ministry Labora-tory ... ... ... ... ... ... ... 551

(ii) On a new means of ascertaining the mean pressure in aheat engine.—By H. E. Wimperis, M.A., F.R.Ae.S.,M.I.E.E., Superintendent, Air Ministry Laboratory ... 568

VI

PageEngines— continued.

(iii) R.A.E. electrical indicator tor high speed internalcombustion engines, also pressure gauge tor maximumpressures.—By H. Wood, A.M.I.M.E., of the R.A.E,Presented by tlie director of Research ... ... 376

Fire Prevention :—(i) Note on temperature measurements.—By F. M. Green,

M.Inst.C.E., and W. Renwick ... ... ... ... 586Aerial Navigation :—

(i) The accuracy of bextant observations taken troinaircraft.—By B, M. Jones, M.A.. A.F.C., Francis Moncl,Professor of Aeronautics, University of Cambridge ... 589

Til

INDEX TO SERIAL NUMBERS OF THE TECHNICAL REPORTS.

Report No. R. & M. 789789

791

792

793

797

798

803

806

807

810818

820

821

822

823

824

825

826

828

829

830

832

Page... 414

... 347

... 391

... 404

... 47

... 551

... 568

... 60

... 576

... 589

... 362

... 397

... 371

... 273

... 275

... 74

56

... 106

... 279

... 174

... 240

... 428

Report No. R. & M. 833„ „ 8&4

835,. » 836

837,, ,, 838

839

840

841

842

843

844

„ „ 845

847

848

„ 849

851

853855856857

858

Page... 81

... 114

... 121

... 286

... 101

... 421

... 433

... 461

... 478

... 490

... 506

... 281

... 542

... 283

... 135

... 322

... 329

... 586

... 147

... 153

... 159

... 337

Till

MEMBERS OF THE COMMITTEE,MARCH, 1923.

Professor SIR RICHARD GLAZEBROOK, K.C.B.. F.R.S. (Chairman).SIR JOSEPH PBTAVEL, K.B.E., J).Sc., F.R.S.J (Vice-Chairman).Brigadier-General R. K. BAGNALL-WILD. C.B.E., C.M.G.Professor L. BAIHSTOW, C.B.E., F.R.S.Major-General Sir W. SEFTO:N BRANCKER, K.C.B.. A.F.C.Professor J. D. CORMACK, C.M.G., C.B.E.. D.Se., M.Inst.C.E.Professor W. E, DALBY, M.A., B.Sc., F.R.S.Lieut.-Colonel E. GOLD, D.S.O., F.R.S.Professor B. M. JONES, M.A.Dr. H. LAMB. M.A., F.R.S.Lieut.-Colonel M. O'GORMAN, C.~B.Mr. A. OGILVIE, C.B.E., M.I.Mcch.E.*Air Vice-Marshal Sir WILLIAM H. G. SALMOKD, K.C.M.G., C.B.,

D.S.O.Mr. J. D. SIDDELEY, C.B.E.fSir HENRY WHITE SMITH C.B.E.fMr. G. I. TAYLOR, M.A., F.R.S.Mr. H. T. TIZARD. M.A.J

Secretary, Mr. J. L. NAYLER.

Assistant Secretary, Mr. H. B.National Physical Laboratory,

Teddington.

* Representing the Royal Aeronautical Society.f Representing the Society of Bntish Aircraft Constructors.J Representing the Department of Scientific and Industrial Research,

REPORT FOR THE YEAR 1922-23

April, 1923,

To Lieut.-Colonel tke Right Hou. Sir S. J. G. Hoaro.Bart.. C.M.G.,M.P., Secretary of State for Air.

Sin,The Aeronautical .Research Committee submit their report for

the year 1922-23.Progress in aeronautical research has, throughout the year,

been continuous but slow ; clue in part to the financial stringencynecessitated by economy and in part to the nature of many ofthe problems that await solution. The Committee are satisfiedthat there is a dibtiiict improvement in the outlook for research,but wish again to draw attention to two points on which theylaid stress in their previous report.

In the first instance, the money devoted to fundamentalresearch is a small percentage of the total vote for Supply andResearch. In view of the smallnesb of the Royal Air Force, theimportance of research in the comparatively new technique ofaeronautical science cannot at the present time be over-estimated.To obtain what may be termed quality to make up for lack ofquantity it is necessary to allot larger sums for research purposes.

In the second instance, the advance indicated by research inany year cannot, in many cases, appear in production until someyears later. Thus, inadequate provision now. affects greatly theposition for future years. Further, the best results arc obtainable,,in the Committee's opinion, by the retention of the bervices of ahighly trained technical staff in the various research establishments,combined with adequate provision of mechanical staffs andmaterial. Funds devoted to research by these staffs will give abetter return to the State than the offer of large sums as prizemoney for limited lines of attack on the problems of flight.

Closely connected with the above is the question of .specificexperiment by the Ministry. The Committee are kept in touchwith the investigations from time to time put in hand as toparticular aeroplanes and their parts, but owing to the fact thatthe information does not always reach them before an experimentis commenced or money committed for definite purposes, itsometimes happens that expenditure is incurred on a specificexperiment when a more general scientific view could show howboth time and money might more economically have been ex-pended. The Committee realise that it is difficult to maintaina correct balance between pure research and its applications,since it is easier to meet the needs of the moment than to await

tlie completion of a lengthy research. Slops have, however, beentaken to meet this need, and the various organisations connectedwith aeronautical research are working in close and friendlyco-operation with one another, so that it is hoped that it will bepossible in the future for the claims of pure research to receivefull recognition.

Personnel.—The personnel of the Committee has remainedunchanged during the past year, with one exception. Lieut.-Colonel Mervyn (VQonnan. now Chairman of three of the Sub-Committees, was in July, 1922, nominated by the Air Ministryas an extra member for the period of one year. The threeindependent members due to retire by rota at the end of theprevious year were re-appointed for a further term of three years.

Finance.—The finance arrangements for the carrying out of\\ork co-ordinated by the Committee remains the same as in thepast year, i.e., part is financed by the Air Ministry and theremainder, having a more general application, is financed by theDepartment of Scientific and Industrial Research.

During the past year the pressure of business on some of theHub-Committees, due to the restriction of the number of meetings,was unduly heavy and resulted in some decrease in efficiencyand co-ordination. In this connection,, the Committee welcomethe expansion in the maximum number of meetings that can beheld during the coming year. In other respects, the steps forensuring economy forecast in the previous annual report havebeen adhered to and will remain in force for the coming year.

Air Transport.—-At the request of the Air Council, a Sub-Committee* has been set up to discuss certain problemsassociated with Air Mail Routes. The terms of reference of theSub-Committee, as laid down by the Air Council, are :—

" To consider the scientific and technical aspects of CivilAviation problems connected with the establishment of anImperial Air Mail Service, and to advise as to the experi-mental work and construction (including both model andfull scale) required for the purpose, with particular attentionto such matters as are set out in paragraph 12 of the report(1922) of the Civil Aviation Advisory Board."

This Sub-Committee will act as a co-ordinating body betweenthe Civil Aviation Department and the Aeronautical ResearchCommittee with its technical Sub-Committees. An officer of theDirectorate of Research has been nominated as a member of tlieSub-Committee to act in a liaison capacity in two connections,(a) to obtain the data which would form the basis for investigations,and (6) to see to the carrying through of experiments recommendedby the Sub-Committee.

* The membership of this Sub-Committee and other Sub-Committeesis appended, (page 15.)

Co-ordination of Research.—An important step towardsincreased co-ordination of research, has been initiated during thepast year. The Secretary of the Committee, who is* a member olthe staff of the National Physical Laboratory, now attends theAir Ministry two days a week and in in direct touch with AirVice-Marshal Sir Geoffrey Salmond. the Air Member for Supplyand Research. He lias. also, free access to papers in the AirMinistry dealing "with experimental work, and a pass to thevarious experimental establishments controlled by the AirMinistry. These facilities assist the Committee in its function asthe co-ordinating board on aeronautical research.

The most important \ \ork of the Committee's organisation isthat dealing with the research programmes in hand at the R.A.E.and N.P.L. Help in also obtained on special problems from the.experimental stations at Martle&ham Heath and Grain. Theprogress of research is often of necessity slow, particularly in thecase of what may be termed fundamental research. It is alsonot easy on many occasions to forecast the final method ofapplication of results arising during research work, but theCommittee wish to lay stress on the point that it is on the basibof thorough investigation in the past and coming years1 that thebest attainments, whether of reliability, performance or manoeuvr-ability, of the aircraft of the next fey, years must nocessariiydepend. The subjects included in these programmes, and othermatters relating thereto, may be conveniently divided into theirappropriate sub-headings, as below.

Equipment for Experimental Work ut the, National PhysicalLaboratory and Royal Aircraft Establishment.— Fall use has beenmade of the experimental equipment at the N.P.L. during thepast year. Steady progress has resulted from the model workin the wind channels, from the research into the elastic andfatigue properties of various metals and from the detonationresearch in the Engineering Department, from the researches onlight alloys and on fabrics and dopes in the Metallurgy andChemistry Department, and from the facilities available in theWilliam Fronde Tank for the testing of seaplane models. Itshould here be noted that the various departments of the N.P.L.have sufficient lengthy and important programmes to ktep themfully occupied for some years.

At the R.A.E. the curtailment in numbers of staff for riunungthe wind channels which could, if funds permitted, be employedcontinuously on useful research work, has retarded the progressof some of the investigations, and it is a matter for considerationwhether the restoration of such staff to these valuable activitiesmight not usefully be made.

On the full scale side of the work, owing to the transfer of theflying previously carried out at the Biggin Hill experimentalestablishment, conditions have been somewhat abnormal this

4

year. It is understood that the existing staff will suffice for nextj^ear's work under normal conditions. Increased fdcilitie& andpersonnel may, however, be needed in connection both with theprovision of certain aeroplanes built bolely for research purposes,the design of which is now well in hand, and with the specialexperimental programme on performance and on control whichis being carried out by Captain G. T. R. Hill under the directionof Professor L. Bairstow.

Aerodynamics.—Hafety has been a first consideration, and inthis connection, much full scale and model work has been completedand projected, both on the stability of aeroplanes and on varioustypes of control.

The general research on complete models at the N.P.L. to{ind their stability derivatives has been continued during thepast year. Data have now been accumulated for the longitudinaland lateral stability of several machines and have been published.iSuoh data are of considerable value and can only be readilyobtained by model work. From this and other model work,the full scale researches on control above the stalling angle havebeen made posbible. In addition, work has been commenced onthe large scale Bristol Model in the Duplex channel for comparativetests with the full scale experiments at the R.A.E. on performanceand stability. This last is the fu'bt instance in this country of\viiid channel tests on a complete aeroplane model with theairtcrcw running.

The results of the model work on control have been publishedand a preliminary report on the full scale flying tests will bepublished later. For further research the Committee haverecommended the construction of three two-seater biplanes solelyfor experimental purposes ; of these, two have already beenordered. The design of the type of machine considered to be themost convenient is now well in hand. The number (3) was clsosenas the minimum which will enable experiments to be carried outcontinuously on one aeroplane while modifications, repairs, &c.,are in hand on the other two. The machines would be used inthe first instance for experimental flying in attitudes of flight atand above the stalling angle ; they will later be available forother experiments and will fill a need, long felt, for a machinespecially designed and adaptable for research work.

In connection with these experimental machines, a furtherproposal has been made for the design and construction of anundercarriage capable of absorbing a specially large amount ofshock. Such a design would not in the first instance be greatlyrestricted by considerations of weight or head resistance andwould be tested in the appropriate experimental department atthe R.A.E.

The results already achieved at the R.A.E. in the abovedirection are distinctly encouraging, particularly as regards the

full scale experiments on stalled flight, and the Committee wishto pay a tribute to the skill shown by the pilots in this pioneerwork.

The present position is, however, that although maintainedstalled flight is definitely possible, neither the stability nor thecontrol of the aeroplane is such that flight near the groundmay yet be regarded as safe. Since there is no doubt as to theadvantages to be gained by making it safe, and since there do notappear to be any insuperable difficulties in the way, there is avery strong case for pushing forward in the large field ofexperimentation now opened up as one of the most promising linesof development of aviation.

Mention was made in last year's report of an internationalscheme under which standard models of an aerofoil and, anairship should be tested in the various aeronautical laboratoriesof the world. On the completion of the British tests, the aerofoilmodel was sent to France and the airship model to U.S.A. TheFrench authorities have now forwarded the results of their tests,made at St. Cyr and Auteuil (Eiffel), on the international R.A.F.15aerofoil. The Committee await with interest the results fromother aerodynamic laboratories.

Much work has been completed in connection with theinvestigation of scale effect, i.e., the corrections that have to bemade to the results of model tests to make them applicable tothe full scale aeroplane. Work on a Bristol Fighter shows a smallconstant difference in the value of the drag coefficient for thesame lift coefficient, the full scale value being less than the valueobtained from the model. There is excellent agreement betweenmodel and full scale as to the relative merits of the three aspectratios tested. The Committee will shortly be able to review theposition and bring up to date the report previously issued onthis matter five years ago.

Amongst other matters under discussion the Committee haveexpressed a wish that some work on gliders might be commencedby the Air Ministry, and facilities provided for co-operationbetween glider clubs and the research establishments. At thesame time the Committee have replied to an enquiry from theAir Ministry that they do not at present see their way to layingdown a direct programme of experimental research with gliders,although they do not wish to neglect this new avenue of explorationinto the problems associated with flight. In particular, advanceis resulting from experiments on gliders with small engines,corresponding with lightly loaded aeroplanes of about 2 Ibs. persquare foot, a suggestion first commended by the Committee in1920.

Many other matters are receiving attention and are describedin detail in the supplement. They include experiments on soundsfrom airscrews, the application of the Prandtl vortex theory ofthe flow over aerofoils as applicable to aeroplane wings and to

6

airscrews, the development of instruments for full scale research,the improvement of wind channel technique, the discussion ofthe results of the now completed tests on the family of airscrewsand a general research on thick and high lift wing sections.

<Smp/«?)f.9. — All the above relate solely to the aeroplane.Research on seaplane problems has also received attention, andthe William Fronde Tank at the X.P.L. has completed during theyear a number of tests on (lying boats for the Air Ministry.During the coming year the following programme will becommenced : («) Investigation of the stresses experienced onhulls when alighting and travelling on the surface oi the water,(6) Investigation into methods of construction and structuraldesign, and (c) Investigation into the effect of steps and load onstability. These items comprise the more important outstandingproblems awaiting solution.

v.s. — Reference was made in the previous annual reportto the formation, on the authority of the Air Council, of a specialPanel to examine the validity oj the methods in use for calculatingthe ^tresses in airship stinctures and to consider any othermethods enabling a closer basis of design to be obtained. Duringthe present year the Panel have reported, giving the outline ofa new general theory fur the calculation of the stresses in thistype of structure. In addition, the outstanding results of certainfull scale experiments on airships made some time since havebeen \\ritten up for publication. They show the inadequacy ofour present knowledge and the necessity, if progress in design isto result, for further full scale experiments with airships, wheneverthey are again constructed in this country.

/?/?(?!'« c. 9. — With a view to increasing our knowledge of enginereliability and in accordance with a recommendation of theReliability Panel that tests should be undertaken, the authoritiesat Farnborough have subjected certain foreign engines to thestandard Air Ministry type tests. These tests have recently beencompleted and the results reported to the Reliability Panel.One of the engines tested was remarkable for its fuel economy.and this is being investigated. In general, the examination ofthese engines shows that the weight per hor.se power is greaterthan that of the average British engine, and so far as these enginesare an index the Reliability Panel have come to the conclusionthat they are not superior to British designs of the sameperiod.

The general programme for research into detonation is beingpursued on the lines laid down and referred to in the previousannual report. The influence of internal pockets and passageson this phenomenon has now been investigated and a considerableamount of work on air-petrol mixtures has been done.

Some interesting experiments on a single cylinder direct-injection heavy-oil engine have been made at the R.A.E., and

are still proceeding. If it be found possible to build a successfulaeroplane engine of thib type, some of the more complicateddetails of power plants of to-day will be eliminated, e.g., thecarburetter and magneto.

A magneto suitable for any aeroplane engine is under con-sideration in connection with the industry, with a view to makinguse of the results of the large amount of work already completedon ignition problems at the R.A.E. A number of special difficultiesarise in connection with the aircraft magneto due to the necessityof screening it to prevent interference with wirele,-,s operationsand to its use at heights. Progress in this subject has been slowduring the past year, but there is a prospect that additional staffmay become available during the coming year.

Co-operation with various universities on engine research hasbeen initiated. A single cylinder unit suitable for research purposeshas been designed by Mr. Ricardo, and the Air Ministry haveprovided two of these at the Universities of Cambridge andDurham and also a universal test bed for Manchester University,to carry out research work in co-operation with the Committee.These units will be used for researches under the general directionof the Engine Sub-Committee. It may be mentioned that theCity and Guilds (Engineering) College possesses a Ricardo setand will co-operate in any general plan of research.

A number of other matters bearing on aircraft engines havebeen under discussion. The apparatus for testing big end bearingswill shortly be traiibfr-rred from the makers to the N.P.L., whenresearch on this subject and on allied problems in lubrication willbe commenced. The Air Ministry Laboratory have tested out,with the assistance of the R.A.E. staff, the Callendar Airflowmeter in flight, and the instrument has given very satisfactoryresults (a report of the experiments has been issued). The R.A.E.have developed an excellent pressure indicator which gives recordsof pressures on diagrams remote from an engine when runningat 2,500 r.p.m. ; some samples of this instrument are now underconstruction and will be used for engine research at variousestablishments. In connection with this last instrument a pressuregauge to record maximum pressures has been evolved ; bothinstruments have been described in published reports.

Accidents Investigation Sub-Committee.—Reliability of all partsof an aeroplane is essential not only for achieving the objectivesof flying, but also for the elimination of accidents. Erom time totime in the past it has been to the successful investigation ofaccidents that development of aircraft has been due. Thealternative of systematic research directed simultaneously to eachand every element of the design is a counsel of perfection whichcan only be followed as rapidly as may be permitted by the con-ditions under which the research can be carried out. The studyof certain elements is indicated, by the incidence of accidents, as

8

being more urgent than others. The Accidents InvestigationSub-Committee have, during the past year, gone forward onestep further in this direction by attacking the general question offailure wluch normally precedes accident, and this has led themin the first instance to consider the possibilities of elimination ofpower plant stoppages.

From their experience in investigating accidents which havebeen referred to them from time to time, and from much otherincidental information, this Hub-Committee have l)een broughtto the conclusion that the stoppage of the power plant is one ofthe most frequent initial elements in an accident. The minimisa-tion of such stoppages is, therefore, imperative.

Data have been provided direct by all the home squadronsby permission of the Chief of the Air Staff and by the AerialTransport Firms, and it appears certain that the stoppages of thepower plant are of sufficient frequency and significance to warrantthe most serious attention both of the Royal Air Force and of thefirms. Pending the attainment of a higher standard of technicalknowledge amongst some at least of the officers of each squadronof the Royal Air Force, a matter requiring some years ofdevelopment, it has tieen recommended that the Air Ministryappoint a group of technicians to spend their whole time ininvestigating the various power plant stoppages which occurfrom time to time at the different stations. The general economywhich it is estimated would, within one year, be effected by such8 scheme, justifies its adoption. Not only would the number ofaeroplanes and engines written off l»e appreciably reduced, but itwould direct attention to the more urgent problems, assist intheir solution, help to disseminate among all stations knowledgeacquired in any one locality and add to the reputation of theRoyal Air Force as well as to the safety of general flying. Preva-lent causes of stoppage are referred to in the Supplement to thisReport.

. — The question of fire prevention, an importantfactor in the reliability of aircraft, is a matter which has receivedmuch attention in the past and has resulted in the recommendationof certain precautions in the construction and installation of thepower plant. These recommendations need embodiment in theregulations governing the specifications of new types of aircraftso as to reduce still further the existing risk of fire.

The arrangement of petrol systems has been the subject of aspecial report to the Air Ministry. Fire risks both in the air andon the ground can be reduced by simplification of certain fuelsystems in common use. Many are unnecessarily complicatedand thLs is in part a heritage from the regulations laid down inthe first instance to meet war risks. The question of location ofthe tanks and petrol pipes, and of the ignition cables, is also ofimportance and seems at that time to have received little or no

attention. Simplification will lead not only to less fire risk, butalso to less risk of accident from power plant stoppage, and in thisrespect considerable improvement has already been made in civilaircraft. The following are examples of the suggestions approvedby the Committee.

In general it is preferable that petrol tanks be placed awayfrom the engines. In the case of single-engined aircraft it isdesirable when possible to place them on the wings, and thoughin some installations difficulties occur, these can be met by carefuldesign. A gravity feed for the petrol is considered preferable toany form of pressure feed. The introduction of safety valves(or bursting discs) in all petrol tanks, and in certain cases extralarge air vent pipes, is desirable and the additional weight requiredmay be justified. All-metal pipe lines have been tried out bothin this country and in the East, and are preferable to any otherform of piping with which the Committee are acquainted. Thefire risks and chances of stoppage from Petrol Resisting rubbertubing and soldered joints is high, and to a lesser extent there isa risk from the use of the more recent substitute, viz., Petroflextubing, which embodies gold-beater skin.

Simplification of certain existing petrol systems on multi-engined craft will result (1) from the use of gravity feed, (2) bythe use of a common collector box, and (3) by the location, insome cases, of petrol pumps in the tanks.

At the request of the Fire Prevention Sub-Committee, experi-mental work at the R.A.E. is being directed to reduce a mostimportant cause of fire on crash, viz., the high temperature ofthe exhaust pipes. In one experimental machine this has beenreduced well below the limit, shown by laboratory experiments to besafe, of a maximum temperature of 400° C. Other experimentsare in progress to determine the size of the safety vent pipes forcertain sizes of petrol tank, and the results of these experimentsare awaited with interest.

The drawback of weight which is one of the objections citedagainst the fireproof bulkhead has been minimized by the light-weight design produced and tested out at the R.A.E., and shouldbe fitted to all single engine aircraft to separate the engine fromthe rest of the aeroplane. This will facilitate the adoption andenforcement of this and other precautions already recommended,but not yet made compulsory. Concurrently, the R.A.E. arecontinuing their research to find a more satisfactory light-weightfire-extinguishing material than is at present available.

Meteorology.—Discussion on meteorological questions has beenlimited to problems which affect jointly the sciences of aviationand meteorology. A new method of computation of windvelocities at heights has been put forward by Mr. L. I1. Richardson,and copies of the method have on the Committee's recommenda-tion been circulated to various observers by the Director of the

(B7984) B

10

Meteorological Office. The question of turbulence in the atmo-sphere has been made the subject of an experimental programmeat the B.A.E. A paper has been communicated on the size ofdroplets in fog and haze, and will be published. Attention liasbeen drawn to the possibility of air from the N.W. quadrant(Polar Air) being instrumental in increasing the risk of accident,and data on this matter from the meteorological point of vieware being collected. A large scale camera for the measurementof the height and motion of clouds has been projected and atrial is being made.

Navigation.—The Committee have been kept informed ofprogress in various directions with instruments for aerial naviga-tion. Several types of turn indicator have been tried out in flight.A form of leader cable has been designed and a successful modelconstructed : half scale tests will shortly be made. The methodsof measurement of wind direction and velocity from an aeroplanehave been discussed. The Committee have also been keptinformed of the excellent work on survey nights carried out underthe direction of Professor Jones, at Cambridge University.

Materials.—A gre^it deal of experimental work on fatigue inmetals has been carried out during the year at the Governmentestablishments and at the Universities. Most of the work hasbeen directed to the elucidation of the nature and mechanism offatigue failure, but several important practical results have beenreached. The 1ST.P.L. have determined the effect of the B.E.S.A.standard Keyways in weakening shafts under torsional fatiguestresses. Mr. Norman Thomas, working under Professor Jenkinat Oxford, has determined the effect of scratches and grooves,such as result from many types of machine shop finish, inweakening shafts : this weakening effect is not so great as wassupposed. Dr. Aitchison has shown that certain variations ofheat-treatments occurring sometimes in practice do not lower thefatigue strengths of the steel.

Several theories of fatigue have been proposed, but thecomplete explanation has not yet been found.

Work on the electro-deposition of various metals on aluminiumwith a view to the prevention of corrosion has been carried outat Sheffield University in co-operation with the Committee.Satisfactory adhesion of various metals, including cadmium, hasbeen obtained on curved surfaces, but the use of cadmium as acovering for aluminium carburettors to prevent corrosion doesnot show great promise owing to the complexity of their con-struction. In the case of aluminium crank cases, &c., corrosioncan most satisfactorily be prevented by the use of a suitablepaint. Further work on this matter is limited to the constructionand trying out of a number of aluminium pistons coated first withoadmium and then with nickel. The results of all the work on

11electro-deposition will be published. It is understood that theResearch Department, Woolwich, has made considerable progressin this subject.

A number of reports have been published on the researchesinto the properties of light alloys as investigated at the N.P.L.The methods of producing and heat-treating chill castings ofthe '• Y " alloy (containing 4 per cent, copper, 2 per cent, nickel,1| per cent, magnesium, and the remainder aluminium) havebeen caref ully investigated on a laboratory scale and will later betried at the R.A.E. in larger units. If proper heat treatment begiven, good castings of high tensile strength and a satisfactoryelongation can be obtained. The constitution of the group ofalloys containing " Y " has been investigated, the range of thegroup including up to 12 per cent, copper and 10 per cent, nickel.A paper is to be published dealing with the ternary alloys ofaluminium with magnesium and copper, and their age hardeningproperties. The heat treatment and mechanical properties ofalloys of aluminium with small percentages of copper have alsobeen investigated.

Questions relating to fabrics and dopes have received someconsideration, but the programme of work on this subject hasbeen appreciably reduced. Steps are being taken to pursueduring the coming year some of the more important problems,including experiments directed towards the maintenance oftautness of fabric under all conditions, experiments on theinflammability of fabrics and on materials for impregnating thefabric on the portion of the wings around the engine to makeit fireproof, the development of methods of obtaining cellulosefrom wood, and an investigation of the failure of the attachmentof fabric to ribs in the region of the slipstream.

Publications.—Appended is a list of papers approved forpublication during the past year.

Signed on behalf of the Committee,

E. T. GLAZEBROOK,Chairman,

12

The following reports have been approved for publicationduring the year and can be obtained from H.M. StationeryOffice :—

R.&-M.No. Title. Author.

AERODYNAMICS.MODEL EXPERIMENTS (AEROPLANES).

826 An investigation of the influence of down-wash on the rotary derivative M,.

829 Experiments with a family of airscrews :including the effect of tractor andpusher bodies. Part I.

830 Experiments with a family of airscrews :including effect of tractor and pusherbodies. Part II.

831 On the effect of sideslip on the aerodynamicforces and moments (including those dueto the controls) for a model S.E.Saaeroplane

834 The Handley Page slotted wing835 Test of four slotted aerofoils supplied by

Messrs. Handley Page Ltd.848 Rolling and yawing moments due to roll

of model Avro wings, with standardand interplane ailerons and ruddermoments for standard and special largerudder.

855 Some suggestions for improving aeroplanecontrol at low speeds.

856 | Experiments on slot control857 Biplane investigation with R.A.F.15 sec-

i tion.

FULL SCALE EXPERIMENTS (AEROPLANES).836 The manoeuvres of inverted flight849 The effect upon the control of an aeroplane

of carrying load distributed along theplanes.

851 The comparison of the manoeuvrability ofaeroplanes by the use of a cinematographcamera.

GENERAL.797 On the rate of tiansmission of heat from

the walls of an airship passenger car.806 j On the theory of rectangular and tapered

| aerofoils.824 A method of calculating the characteristics

of a tapered wing.825 The singing of circular and streamline wires833 The design of tapered wings837 An empirical method of predicting the

aerodynamic properties of an aerofoil.

Simmons and Ower.

Fage, Lock, How-ard and Bateman,

Fage, Lock, Bate-man and Wil-liams.

Irving and Batson.

Glauert (R.A.E.).Bradfield (R.A.E.).

Bradfield and Sim-monds (R.A.E.).

Fage.

Irving.Cowley and L. J.

Jones.

Hill (R.A.E.).R.A.E.

Francis (R.A.E.).

Miss Marshall.

Fage.

Glauert (R.A.E.).

Relf and Ower.Farren.Thorn.

13

R. &-M.No.

822

823

828

844

847

854

814

827

858

791

792

793

819

820

821

Title.

AERODYNAMICS—continued.EXPERIMENTAL APPARATUS.

An attachment to main balances formeasuring three forces and three mo-ments.

Description of lift, vertical force and drag-balances for the roof of the Duplex WindTunnel.

A continuous rotation balance for themeasurement of LP at small rates ofroll.

A direction and velocity meter for use inwind tunnel work, &c.

The No. 2 7-ft. wind channel at the RoyalAircraft Establishment.

The measurement of aeroplane speed withspecial reference to the use of a sus-pended static head.

AIRSHIPS.Experiments on Rigid Airship R.32, Part

IV. Note on measurement of airscrewthrust.

The prediction of the resistance of rigidairship R.33.

The resistance of a spheroid, with specialreference to the effect of wires placedaround the model in a plane at rightangles to the axis.

STRUCTURES.On the determination of the stresses in

braced frameworks. Part III. The effectof axial loading, torsion, flexure and shearupon a braced tube of any uniform crosssection.

The reduction of the effective value ofYoung's modulus in flexible compressionmembers.

On a method for the direct design of framedstructures having redundant bracing.

On the determination of the stresses inbraced frameworks. Part IV. Theeffects of axial loading, flexure, torsionand shear upon a tubular frameworkwith taper.

Stresses in a stiff jointed polygonal frameunder a system of parallel loads.

On Castigliano's Theorem of least workand the principle of St. Venant.

Author.

Lavender, Fewsterand Henderson.

Fewster.

Relf and Lavender.

Lavender.

R.A.E.

Stevens (R.A.E.).

Frazer and Bate-man.

Frazer and Gadd.

R. Jones and Bell.

Southwell.

Sutton Pippard.

Button Pippard.

Southwell.

Sutton Pippard,

Southwell.

14

R.&M.No.

789

832

838

845

839

840

841

842

843

798

803

807

853

810

Title.i

MATERIALS.Preliminary Report on the properties of

commercially pure nickel as a standardmaterial for fatigue investigations.

Report on the influence of calcium and ofcalcium phis silicon on aluminium.

The mechanics of the Wohler rotating barfatigue test.

Report on further investigations of theeffect of sunlight on aeroplane fabric,with appendix by Guy Barr, D.Sc.

The constitution and age hardening ofalloys of aluminium with copper, mag-nesium and silicon in the solid state.

The constitution and age hardening of theternary alloys of aluminium with mag-nesium and copper.

The heat treatment and mechanical pro-perties of alloys of aluminium with smallpercentages of copper.

The production and heat treatment of chillcastings in an aluminium alloy (" Y ").

The constitution of some alloys of alumi-nium with copper and nickel.

ENGINES.Air consumption and B.H.P. of Aero

engines.On a new means of ascertaining the mean

pressure in a heat engine.R.A.E. Electrical Indicator for high speed

internal combustion engines ; also pres-sure gauge for maximum pressures.

FIRE PREVENTION.Note on temperature measurements

METEOROLOGY.The accuracy of sextant observations taken

Author.

Hankins.

Grogan.

Prof. W. Mason.

R.A.E. and Dr.Barr.

Miss Gayler.

Miss Gayler.

Hanson and MissGayler.

Rosenhain, Arch-butt and Wells.

Haughton and MissBingham.

Moss.

Wimperis.

Wood.

Green and Renwick

Prof. Jones.from aircraft. j

[

15

MEMBERSHIP OF SUB-COMMITTEES.

At May 1st, 1922, the membership of these Sub-Committeeswas composed as follows :—

Aerodynamics Sub-Committee,—Sir J. E. Petavel, K.B.E.,D.So., F.R.S. (Chairman) ; Professor L. Bairstow, C.B.E., F.R.S. ;Professor B. M. Jones, M.A. ; Dr. H. Lamb, M.A., F.R.S. ;Mr. A. Ogilvie, C.B.E., M.I.Mech.E. ; Mr. G. I. Taylor, M.A.,F.R.S. ; Sir H. White Smith, C.B.E. ; Mr. R. J. Goodman-Crouchand Mr. R. McKinnon Wood (representing Director of Research) ;Mr. E. F. Relf, A.R.C.Sc., and Mr. R. V. Southwell, M.A.(representing National Physical Laboratory) ; Mr. W. S. Farren,M.B.E. ; Mr. F. Handley Page and Mr. J. D. North (representingthe Society of British Aircraft Constructors) ; Lieut.-ColonelM. O'Gorman, C.B. ; Professor A. J. Sutton Pipparcl, D.Sc.,M.B.E. ; Dr. H. C. Watts ; with the Chairman of the AeronauticalResearch Committee (ex officio).

Engine Sub-Committee.—Professor W. E. Dalby, M.A., B.Sc.,F.R.S. (Chairman) ; Mr. A. Ogilvie, C.B.E., M.I.Mech.E. ; SirJ. E. Petavel, K.B.E., D.Sc., F.R.S. ; Mr. J. D. Siddeley, A.B.E. ;Mr. H. T. Tizard, M.A. ; Lieut.-Colonel L. F. R. Fell, D.S.O.,O.B.E., Wing Commander G. B. Hynes, D.S.O., and Major H. E,Wimperis, O.B.E. (representing Director of Research) ; AirCommodore F. C. Halahan, C.M.G., D.S.O., M.V.O. (Directorof Aeronautical Inspection) ; Dr. T. E. Stanton, C.B.E., F.R.S.(representing Department of Scientific and Industrial Research) ;Professor H. L. Callendar, F.R.S. ; Professor A. H. Gibsou,D.Sc. ; Lieut.-Colonel M. O'Gorman, C.B. ; Mr. H. R. Ricardo ;Mr. T. B. Barrington and Mr. A. H. R. Feddeu (representing theSociety of British Aircraft Constructors) ; with the Chairman ofthe Aeronautical Research Committee (ex officio).

Materials and Chemistry Sub-Committee.—Professor C. F.Jenkin, C.B.E., M.A., M.Inst.C.E. (Chairman) ; Professor L.Baii-stow, C.B.E., F.R.S. ; Professor W. E. Dalby, M.A., B.Sc.,F.R.S. ; Sir J. E. Petavel, K.B.E., D.So., F.R.S. ; Mr. J. D.Siddeley, C.B.E. ; Sir H. White Smith, C.B.E. ; Mr. G. I. Taylor,M.A. F.R.S. ; Mr. H. T. Tizard M.A. ; Dr. L. Aitchison and Mr.A. Young (representing Director of Research) ; Air CommodoreF. C. Halahan, C.M.G., D.S.O., M.V.O. (Director of AeronauticalInspection) ; Dr. W. Rosenhain, F.R.S., Mr. R. V. Southwell,M.A., and Dr. T. E. Stanton. C.B.E., F.R.S. (representing NationalPhysical Laboratory) ; Professor F. C. Lea ; Sir R. Robertson,F.R.S. ; Mr. J. D. North and Captain G. S. Willdnsou (representingthe Society of British Aircraft Constructors) ; with the Chairmanof the Aeronautical Research Committee (ex officio).

Meteorology Sub-Committee.—Sir Napier Shaw, F.R.S. (Chair-man) ; Professor B. M. Jones, M.A. ; Mi-. G. I. Taylor M.A.,F.R.S. ; Wing Commander J. B. Bowen andMajor H. E. Wimperis,

16

O.B.E. (representing Director of Research) ; Colonel L. F. Blandy,D.S.O., Lieut.-Colonel E. Gold, D.S.O., F.R.S., and Dr. G. C.Simpson (representing Air Ministry) ; Mr. F. A. Gould, M.A.(representing National Physical Laboratory) ; Mr. G. M. B.Dobson, Mr. W. H. Dines, F.R.S. ; Professor F. A. Lindemann,Mi-. F. E. Smith, C.B.E., F.R.S. , Mr. C. T. R. Wilson, F.R.S. ;with the Chairman of the Aeronautical Research Committee(ex officio).

Accidents Investigation Sub-Committee.—Lieut.-Colonel M.O'Gorman, C.B. (Chairman) ; Professor L. Bairstow, C.B.E.,F.R.S. ; Lieut.-Colonel E. Gold, D.S.O., F.R.S. ; Sir J. E. Petavel,K.B.E., D.Sc.. F.R.S. ; Major J P. C. Cooper (representing AirMinistry) ; Wing Commander T. R. Cave-Browne-Cave, C.B.E.,and Squadron Leader R. M. Hill (representing Director of Re-search) ; Mr. G. B. Cockburn, O.B.E. ; Professor A. J. SuttonPippard, D.Sc., M.B.E. ; with the Chairman of the AeronauticalResearch Committee (ex officio).

Fire Prevention Sub-Committee.—Lieut.-Colonel M. O'Gorman,C.B. (Chairman) ; Mr. G. B. Cockburn, O.B.E. ; Sir J. E. Petavel,K.B.E., D.Sc., F.R.S. ; Wing Commander T. R. Cavc-Browne-Cave, C.B.E., and Lieut.-Colonel L. F. R. Fell, D.S.O., O.B.E.(representing Director of Research ; Flight Lieutenant F. E. J.Coates (representing Directorate of Equipment) ; Mr. F. M. Green,M.Inst.C.E., and Mr. R. K. Pierson (representing Society ofBritish Aircraft Constructors) ; with the Chairman of the Aero-nautical Research Committee (ex officio).

Air Transport Sub-Committee.—Lieut.-Colonel M. O'Gorman,C.B. (Chairman) ; Professoi L. Bairstow, C.B.E., F.R.S. ; Major-General Sir W. Sefton Brancker, K.C.B., A.F.C. ; Wing Com-mander H. M. Cave-Browne-Cave, D.S.O. (representing theDirectorate of Research) ; Sir J E. Petavel, K.B.E., D.Sc.,F.R.S. ; Mr. H. T. Tizard. M.A. • with the Chairman of theAeronautical Research Committee (ex officio).

Air Inventions Sub-Committee.—Sir R. T. Glazebrook, K.C.B.,F.R.S. (Chairman) ; Professor L. Bairstow, C.B.E., F.R.S. ;Professor B. M. Jones, M.A. ; Sir J. E. Petavel. K.B.E., D.Sc.,F.R.S. ; Mr. G. I. Taylor, M.A., F.R.S. ; Major H. E. Wimperis,O.B.E. (representing Director of Research).