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Aviation History
1928
1928 - 0280.PDF
APRIL 12, 1928 H.M. AIRSHIP R.10I iJA PAPER entitled "Some Modern Developments in Rigid Airship Construc-tion," was read by Lieut.-Col. V. C. Richmond, O.B.E., B.Sc, A.R.C.S., ; -:A.F.R.Ae.S., before the Institution of Naval Architects on March 30, 1928.•I in the hall of the Royal Society of Arts. '•\ Col. Richmond said that interest must necessarily be vary critical in• f\the departures from Zeppelin pattern which had been made in the design : ?jof R.101. Some of the changes in design were necessitated by the increase: foi size ; but not all. What were the reasons,.advantages, and risks ? Col. Richmond paid a tribute to the ability of the late Mr. C. I. R. Camp-'bell, some of whose original ideas had been copied by the Zeppelin Co. in the Los Angeles. In the past seven years research had been carried out,and this country was now probably ahead of Germany in that respect. The author then dealt with the question of fineness ratio. A reductionin aerodynamic bending moments would follow a reduction in the length of the ship. The bare hull resistance coefficient of R.33 in the wind tunnelwas 0-010, while that of R.101 was 0-007. Stability and controllability were only a matter of sufficient fin and rudder areas. The wind tunnelShowed that these need not be excessive, as the flow of air over the tail was very smooth. These low resistance forms were more seriously affectedthan the cruder forme as regards drag: not stability) by excrescences, and , R.101 Dad an estimated overall resistance coefficient lower than that ofR.33. Col. Richmond traced the history of the low fineness ratio forms, whichwere first used in the little " Bodensee." He showed that at first it was over- controlled, which gave an impression of instability. When the controlsurfaces were reduced, at the same time the ship was lengthened. Herr Paul Jaray, the designer, attributed the improved stability to the reduc-tion of these surfaces, while Dr. Eckener attributed the improvement to the lengthening. Col. Richmond concluded that the result did not dis-' count the results of the wind tunnel experiments, which showed the low fineness ratio forms to be the more stable. A series of slides was then shown which illustrated details of the hull ofR.101. The ship has no keel, and there are 15 main girders and 15 inter- mediate girders, the latter reducing the stresses on the fabric cover. Notransverse members will touch the cover, and thus there will be no trans- verse ridges to reduce speed. It was also explained that a system of netshad been designed for containing the gas bags, which would prevent them from imposing lateral loads on the longitudinal girders. The design of the transverse frames was described as one of the mostrevolutionary features in the structure of R.101. The single members of the conventional frame were replaced by deep triangular braced structuresmade strong enough to resist all transverse forces without any transverse bracing. The system of wiring was also illustrated. By means of it allend pressures arising from gas pressure were transmitted into the longi- tudinals only and did not stress the transverse frames. The author ex-plained the advantages of this system in the case of a gas bag being partly or wholly deflated. The change from the Zeppelin girder of open channel section to the tubulargirder developed by Messrs. Boulton and Paul, Ltd., was next described. The author emphasised that stainless steel was employed in place of dura-lumin only where weight would obviously be saved. About one-quarter of the weight of the complete structure would be accounted for by steel. The tubular construction, the ends of the tubes being closed, was a pro-tection against corrosion. The outer surface of the steel tubes was lac- quered and the duralumin was treated by the anodic process. Col. Rich-mond prophesied freedom from corrosion for from seven to ten years. Where steel booms were used in the girders, the webs were made of dura-lumin. Dealing with the different rates of expansion of the two metals, figures were given to show that, while the maximum difference of tempera-ture likely to be experienced even in the tropics from the temperature con- ditions under which the girders were manufactured was of the order of30° C, the stresses induced would be:— For steel .. .. .. .. .. 0-98 tons /square inch. For duralumin .. .. .. .. 1 • 14 tons/square inch,which Col. Richmond said represented an almost negligible proportion of the failing stresses of the materials.The tests on the new types of girder and on a complete bay were also described in detail. The results of the tests proved extremely satisfactory. The DiscussionGroup-Captain P. F. M. Fellowes, D.S.O., Director of Airship Development, spoke about the policy embodied in the two new ships. Before airships couldbecome commercial, they must be proved to be robust and able to withstand all stresses in flight and at the mooring tower. A great part of the presentprogramme was to prove that a rigid hull could be made strong enough. They had not hurried but had proceeded cautiously ; and the Air Ministry's policyhad been " Safety first." This programme was the seed, and the fruit would be future developments. The next airships might be made lighter, but theycould not say that definitely until after the trials of R 100 and R 101. Mr Williams said that he had been out of airships for eight or nineyears ; but he had been in the trials of R 23 and others. There had been intemperate criticism of the present airships, and there was always a dangerthat opinion might go with the volume of sound. Col. Richmond's paper had shown ample justification of the present policy. The criticism, when boileddown was that airships Were big, difficult to handle, frail as compared with such structures as cathedrals and marine ships, and subject to aerodynamicforces which were imperfectly understood. He admitted that they were still experimental but not to the same extent as formerly. The slides had shownthe improvement made, and he congratulated Col. Richmond on " getting rid of the infernal Zeppelin joint." But in Zeppelins it was quite sound to accepta lower factor of safety than in marine ships. Mr. E. F. Spanner commenced his remarks by apologising to Col. Richmondfor having assumed that he did not respect Mr. R. I. C. Campbell. He con- gratulated the Air Ministry for coming into the open at last. He said thatthe shape of airships had been "plumped up" (1) to increase strength, (2) to reduce drag, and (3) to make them commercial. He said that comparisonwith the performances of non-rigids was useless, because the non-rigids would flex, which he seemed to claim would make them more stable. As for theBodensee, he thought that Col. Richmond had confused the disease with the remedy. If she were over-controlled, why was not this corrected ? Heconsidered that she must have been unstable on account of the fineness ratio. He displayed a diagram to explain that a rigid rarely travelled on a horizon-tal axis but was nearly always nose up or nose down, which he said would be very uncomfortable for passengers. He quoted Fraser on full scale experi-mental nights, and mentioned an angle of 12" inclination. Mr. Spanner was proceeding to other points when the Chairman pointedout that time was limited, and said that if he would send in any further remarks in writing they wouid be published in the Journal of the Institution.Col. the Master of Sempill wished that he could hear of complete collabora- tion between the design staffs at Howden and Cardington, and also hoped thattouch was maintained with the design staff of the Zeppelin Co. Major G. H. Scott, C.B.E., A.F.C., said that he was more interested inR 101 than anybody else because he hoped to have the honour of flying her. He had watched the methods of design and construction, and was confidentthat she was a strong, sound airship. He was perfectly satisfied that she would be safe. He said that short ships were easier to control than long ones. It waswrong to say that they would fly at an angle of 12°. Mr. Spanner had quoted a trial flight when a ship was deliberately flown at that angle for the purposeof pressure plotting. Mr. R. V. Southwell asked why Mr. Spanner had criticised the design of theship when he did not know what the design was. He had spoken of undue stresses on the fabric, assuming that there would be no intermediate girders—which there would be. Col. Richmond had explained the parachute system of suspension of the gas bags, which he considered the most beautiful feature ofthe design, As for control, he thought it useless to argue with a man who believed non-rigids to be more stable than rigids. He said that after the R 38 disaster they were obliged to make a fresh startwith new men. Were the new men right in attempting new methods ? Ought they to have tried to make improvements by research, or to have clung toZeppelin methods, of which they had really but little experience ? WingCommander T. R. Cave-Browne-Cave, C.B.E., spoke of the strainmeters on the test bay of R 101, and said that they would also be used on the trial flights.Col. Richmond, replying to the debate, said that he could not follow the argument that a rigid was less stable than a non-rigid. As for fineness ratio,if the argument were followed to its conclusion, a sphere would be more stable than a long ship. Mr. Spanner evidently did not know the history of theBodensee, for the control surfaces were cut down when they were found to be too large. She made a very satisfactory ship. Dr. Eckener was not a designer.He was once a bitter opponent of airships but was converted by Count Zeppelin. He (the speaker) hoped similarly to convert Mr. Spanner in duecourse. As for official secrecy, he thought that there was no use in talking while they were dealing with problems and making up their minds. He wantedall possible co-operation and help, and he was glad to say that Cardington was in close touch with the Zeppelin design staff. IN PARLIAMENT All-Metal AircraftLIEUT.-COMMANDER KENWORTHV, on March 29, asked the Secretary of State for Air what firms in this country are manufacturing all-metal aero-planes ; if his attention has been called to the intention to use Junker three- engined all-metal monoplanes on the Cape Town-Johannesburg route on thegrounds that no suitable British machine is available at the same price ; and what information he ha's on this subject T Sir S. Hoare : As regards the first part of the question, most of the Britishaircraft manufacturers have made experimental aircraft of all-metal structure during the past few years, six have brought such aircraft to the productionstage, and two have constructed aeroplanes of which the covering as well as the structure was of metal. As regards the remaining parts of the question,I understand that there is at present no British commercial machine in exist- ence or under design which is strictly comparable to the Junker in so far as thelatter machine is of all-metal construction and entirely covered in metal, but that the price is no cheaper than that of British-built aeroplanes which willcarry the same load. The service in question is not, of course, to be sub- sidised from the Exchequer, and it is entirely for the South African authori-ties to decide the type and origin of the aircraft to be employed upon it. Aviation JurisprudenceSIR SAMUEL HOARE, on April 4, in answer to Mr. Malone, said the Air Ministry will not be represented at the international congress on jurisprudencen regard to aviation, which is being held at Madrid on May 28. PERSONALS Married DONALD BULAY-WATSON, A.F.C., only son of Sir Francis Watson, M.P., andLady Watson of Torracks Hill, Poole in'Wharfdale, was married on March 26, at the Chapel of the Savoy, to GWENDOLYN MAUD MYCOCK, youngest daughterof the late Mr. W. Pritchard Davies, of Woodlands, Chorlton-cum-Hardy, and Mrs. Davies, Boverton, Hampton Wick. To be Married THE engagement is announced, and the marriage will take place in Bombay,India, on May 18, between Flight-Lieut. CYRIL FERDINAND BRIGGS, R.A.F.O., youngest son of the late Mr. Henry Briggs and Mrs. Briggs, of LeightonBuzzard, and BERNICE ZOE, only child of the late Mr. Ernest Mansfield and Mrs. Mansfield, of 3, Hyde Park Mansions, W. Items PRINCESS ANNE of LOWENSTEIN WERTHEIM FREUDENBERG, of UpperBelgrave Street, S.W., who started on a cross-Atlantic flight with Colonel Minchin and Captain Leslie Hamilton on August 31, 1927, and has not sincebeen heard of, has by an order of the Court dated February 6 been presumed to be dead. The Princess left £28,265. THE will of the late Mr. WILLIAM HENRY DINES (aged 72), of Benson, Oxon,an Hon. Fellow of the Royal Aeronautical Society, has been proved at £20,865. London-Lyons-Marseilles Air MailTHE Postmaster-General announces that the despatch daily (except Sundays) of letter mails has been resumed onthe London-Lyons-Marseilles route (Routes 1 and 2, Air Mail Leaflet), but not to Geneva at present. The latest time ofposting at the General Post Office, London, will be 5 a.m. The special fee has been reduced to 2d. per ounce, as for the rest of France. . This route will normally give advantage for letters for the South of France, and on Fridays an opportunity of overtaking at Marseilles (or Toulon) the mails despatched from London by ordinary service the previous evening for Egypt, India, Iraq, Australia, East Africa, etc. 252
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