''ERING CRAFT

THE INTER. .i CUSHION VEHICLES AND HYDROFOILS

SPECIAL RUSSIA N ISSUE iber 1

KALERGHI PUBLICATIONS OCTOBER 1964 HOVERING CRAFT & HYDROFOIL FOUNDED OCTOBER 1961 An artist's impression of the Viekers VA-4 at m Jerry quay. first Hovering Craft IL Hydrofoil Monthly in the World For fitrthcr dctuils see page 4 of this issrtc

HYDROFOILS AND ACVs IN THE USSR

A stafeincnt for Hovering Craft and Hydrofoil's Special Russian issue by Engineer Vladitnir I. Kiryushin, Second Secretary of the Department of Science and Technology at the USSR Et7zbassy in London

N recent years many countries have been devoting great completed this year. intended for Sast passenger service between attention to the building of hydrofoils and air - cushion towns. Vessels of this type seem likely to prove uscful to I replace, or to supplement, the hydrol'oil vessels which are now vehicles, among these being the USSR, where scientific research running regular services on many of the great rivers of and constructional work is going on in these fields. The survey Siberia, such as the Ob', the Yenisyey, the Lyena and others, which appears in this issue of Hovering Craft K. Hydrofoil is as they would enable passenger transport services to be based on articles which have been published in various Soviet maintained throughout the year, i.e. even when the rivers newspapers and technical journals, and gives some idea of the are ice-bound. It is particularly noteworthy, moreover, that actual work on methods of calculation and construction of air-cushion vehicles are very useful as a means of transport in new types of hydrofoils and ACVs which has been carried those parts of the USSR which have only recently been out in the USSR. opened up, and where there are still few roads and railway It must be well known that the USSR has accumulated a lines. good deal of experience in the construction of hydrofoil Work on the development of air-cushion vessels is conducted vessels, which are nowadays in regular service in various parts in close collaboration with various scientific research estab- of that country. Cireat attention is now being paid there, more- lishments, and the industrial establishments concerned have over, to the development ol air-cushion vehicles, for which benefited greatly from the help of the celebrated research wide use may be found in the conditions which obtain in the workers of N. Ye. Zhukovskiy Institute of Aerodynamics. The USSR, owing to the geographical and climatic conditions oE Director of that Institute, the famous Soviet aircraft designer, certain areas, in which the use of air-cushion vehicles is pre- V. M. Myasischev, visited Britain recently, together with ferable to that of other means of transport. several other specialists of the Soviet aircraft industry, as Krasnoye Sormovo shipyard at Gorki, on the River Volga, guests ol the Society of British Aircraft Constructors, for the is building an air-cushion vehicle, the Delfirz, which will be 1964 Farnborough Air Show.

Areas for the Effective Use of Hydrofoil Vessels OCTOBER,1964 VOL 4, NO 1 and Hovercraft 3 People and Projects 4 Editor: The Latest in Soviet Hovercraft 8 JUANITA KALERGHI A New Type of Engine for Hydrofoil Vessels 10 HOVERING CRAFT AND HYDROFOIL is produced by Kalernhi Psblicarions. 53-55 Beak Street, London, 1V1. Development of Anti-Cavitation Erosion Alloys 12 T~lrphone:GERrnrd 5895. Prrfrte(1 in Great Brirain hy Vil!ie~ Puhlicarions, Londorr, NWS Anrrrral srrh- A Note Concerning Cavitation on Hydrofoil Propellers 14 scrrprron: Fi1.e Grrirtens UK and eqrrivalcnr over.7Pa.s. USA urid Ca~iacla$15. There rrre rwelve issrrcs arrnuall),. Across the Solent, 1964 16 Corrtenrs of this issrre ore rhc copyriphr of Kalerphi Pt~blicarions. Permission to rcpvoduce picrrrres and rcxr Practical Experience with cnrr be prurlred only under ~vrirrcri ngreement. Exrr(rcls the Power Unit of the Hydrofoil Motorboat "Vikhr" 18 or corrrrncnrs nay be ntnde with due rtckno~olcdpen~err~ ro Hoorrirrp Craft find Hydro Joil. The Determination of the Stability of Vessels on Shallow-Submerged Foils 20 ADVERTISING REPRESENTATIVES GREAT BRITAIN B EUROPE: Ifrrcrnatiorinl Grapliic Stability of the Terraplane on the Ground 22 Press Ltd, 2 Dyers Brrildi~rgs, Londo~i, ECI; NORTH AIMERICA: 1Y. J. Moslsr.~orr Co, 110s 298, YOII~P~SI, NPIV York. USA; JAPAN: Japnn Trnde Service LrJ, iMrrsatni Brrilding. 1;ZU Knfrda Jb~rhaclro. Chivodn-ku. COVER PICTURE : Three Russian hydrofoils of the "Rakcta" Tokyo, Japmr: HOLLAND: G. Artrolrl Tt.esirrg, A~nsrer- arld "Sputnik" class at speed on the Volga. (Photograph by dam-Z, Rrrhenssrraor 68a. Hollnrrd. corrrtesy of "Tass") Areas for the effective use of hydrofoil vessels

Figure I. Specific powers and hovercraft Hovercraft (hoverheight 8 in) • Hydrofoil vessels - - - - - Line of equal specific power for hydrofoil vcssels and hovercraft

Engineer V. M. Pashin

INCE the range of speeds attainable by hydrofoil vessels and S hovercraft, respectively, overlap each other, the deter- mination ol' the point at which, lrom a power point of view, one or the other of these two types of vessel becomes the more efficient for normal use, must be arrived at by com- parison of the power per unit weight required for each of the types for various dimensions and at various speeds. So Car as hydrofoil vessels are concerned, the specific power was worked out and shown in a Paper on "Hydrofoil Vessels", presented by M. V. Shaybo of the Academy of Sciences, to the Academy of Sciences of the Ukrainian Soviet Socialist Republic in 1962, and published in Interavia IV, Vol 16, No 4, 1961, pp 479-484. It was assumed in that Paper that foils working in sub-cavitating conditions would be used at speeds ol up to 60 knots, after which these would be replaced by foils working in super-cavitating conditions. The results arrived at were as follows: at 50 knots. 55 hp/ton; at 70 knots, Figure 2. Areas of effective use, from a dy~zamicpoitlt of 110 hp/ton; and 90 knots, 200 hp/ ton. Changes dependent on view, of hydrofoil vcssels and side-wall hovercraft tit variorrs the dimensions of the vessel were too insignificant to be taken hover heights into account (Transactions of the Society of Naval Architects ----- Curves of constant power of 50,000 hp and Engineers, Vol 67, 1959, pp 686-714). The specific power for hovercraft of the air-cushion type were calculated by applying the exponential theory to a two- dimensional plan (lolrr~icilof the Aerospace Scietlces, VII, Vol 29, No 7, 1962). and it will be seen from Fig. 1 that it changes with the increase of the dimensions of the hovercraft. Similar changes are observed with a side-wall hovercraft also. Fig. 1 shows the curve for a constant power of 50,000 hp (which may be obtained either with a nuclear power installation (Trans- trctions oJ the Socicty of Ntival Architects trrzd Engineers, Vol 67, 1959. pp 686-714) or with a gas turbine installation (Hover- ing Crrift tu~dHydrofoil, Vol I, No 7, 1962). By using graphical representation similar to that used in Fig. 1. it is possible to determine the speed and weight of hydrofoil vessels and hovercraft, respectively, at which the specific power will be the same (Figs 2 & 3). Comparison of the dynamic characteristics of hydrofoil vessels makes it possible to arrive at the following conclusion: 1. At speeds of 70-80 knots with vessels of small dimen- sions, corresponding with displacements of 50-100 tons, hydro- foil vessels are the more eflicient, so far as power consurnp- tion is concerned. With larger vessels, however, hovercraft are a preferable. 2. Proportionally as the speed is reduced and the hover- height is increased, the range over which hovercraft may be Figure 3. Arcas of etfective usc, from a dynamic poitit oJ used economically becomes smaller. vic~,.,of hydrofoil vessels and air cushion vehicles Adapi~dtranslotion from Rirssian of an article in "Sudoslroyeniye", No .5, 1964 M. A. Yrrr~li,v,Dircccor of the Krusr~oyrSorr~ro~~o Slripycrrd, trr~rlH. E. Alc.rcyr~,,Lct~itl Prizc I.trrrrctr/c ntld Clric.1 Desigrrer of /Ire Shipyard, sc~rt ~virh111e modcl of tr IICIV ,c~trtrr-jc/propcll(,d hydrofoil People and Projects Thc world's largest hydrofoil-a 112 million virtually all- Viekers-Armqlrongs Itd havc now finalized the dcsign of aluminium experimental craft ior the US Navy -is being thcir new hovercraft, the VA-4. Initially schemed to carry built in Scattle by Puget Sound Bridge and Dry Dock Com- twenty-four cars and 200 passengers, the 150 ton craft will be pany, a subsidiary of Lockhecd Aircraft Corporation, for capable of a top speed of ovcr XOmph. with an endurance delivcry in autumn 1965. of thrcc-and-a-half hours providing an elfcctivc operating Designated thc AG(EH) Hydrofoil Research ship, the craft rangc. The incorporation of the Vickers flcxible skirt system will be 220 it 5 in long and 40 ft 5 in in beam, with a dis- will enable the craft to operate at spccds of 50mph in 6 ft placement of 300 tons. It will be more than twice the size of wave cond~tions. any hydrofoil in existence. Lectdirzg particrtlnrs : The ship will be of all-welded aluminium construction All up weight: I50 tons csccpt for foils and struts, which will be of steel. Of the more Disposable load : 65 tons than 250.000 1b of aluminium that will go into the hydro- Length overall: 133 I't foil, at least 200,000 Ib will be in the form of large extrusions, Width overall: 71 11 sorne as long as 40 1'1. Kaiser Aluminium and Chemical Cor- LiCi Cans cenlrifugal : Three 114 Tt diameter poration is supplying these extrusions of alloy 5456 H113, and - Propulsion propellers : Three 20 ft diameter the plate of alloy 5456 H321. - Engines : Three Bristol Siddeley Marine Pmteus * * * Power (continuous cruise raling) : Three 3,400 shp On September 9th the New Zectlmld Herald reported that Fuel (normal load) : 2,800 gallons thc Waiheke Shipping would definitely buy a new and Co Ltd, Endurance: 3) hours largcr hydrofoil after the "Manu Wai" had proved itself and Crew (driver, navigator, three stewards) : Five thc Company had more expericncc of running it. No order has yct becn made but thc new hydrofoil the Company had Typical loads C'(rr.s Pcrssetrgcrs in mind was thc 130 ton PTSO which can carry 130 passengers at 33 knots cruising speed. It was further stated that the craft High density Economy class - 600 has a rangc of 377 miles, and it is believed that Sir Robert Low density First class - - 450 Kerridge plans cruises far beyond the Auckland harbour. Low density seating 16 220 In addition to the present service to Waiheke Island, the Tourist class I6 320 "Manu Wai" will scrve the Pakatoa Island Tourist and Holi- Tourist class 24 196 - day resort, now under construction, which should be open by the cnd of the year.* * * The "Rrirc~vestr~ik",cluit?~c,d to hc on ridvcincr or1 cir~y hydrofoil vc,sscl it1 c~xistrrrce,~vc1.7 lo~rr~ched irr April 1%4 6). !Ire Krost~oye Sormovo Shipyard. It curries I50 pctsserlgers nnd will operate on large ;nlcrnd scjus ot~drivcrs rvitl~~r~iilc rrnclrcs which urc, csiremely shrrllo)~.It is fitted ~vithshallon. droriglrt sribmerged foils urzd curl operclic, it1 wuves of 1.2 rn. The croft is propcjlled hy t~vowater- jets, irrstc~crd of propellers, thc power for thcse being provided by two mtiriiliscd uircrcifi-type gus-trrrbines, crrch rlcvclopir~gan orciput of 2,000 hp. The two etzgines have cr consumption of bout 300 galloru per hour. Tcn tons of fitel run />a curried, and this enables 500 km of tlotl-stop operation. The water-jets help monoerrvrability, provide grcjtiter mecl~nnicnlefficiency, orrd very substut~ticil reductiotz of draught. The hrill is cor~structed of all welded crlumir~irim-mrigt~esi~fmalloy, citzd the foils nre mudc of titnnirrm alloy. The foils arc secured to the hull by columns and brackets, and the angle of incidence con thrrs be changed when docking. Therc, is o crew of four, ur~dsaloons are air-cotzditiot~ed. Length 43.3 m; width 6.7 rn; height 3.7 m; cruising speed ubout IIO kmlhr; static draught 1.8 m; at speed 0.4 rn: displaccmcnt at frill lond 61 tons.

On September 29th Bell Aerosystems Company began dem- A lecturc entitled "Hovcrcraft" was delivered by Ci. T. - onstrations for the first time in the United States of a West- Thomson, of Westland Aircraft Ltd. at a meeting organiscd by land SR.N5 air cushion vehicle. The demonstrations were the British Association for the Advancement of Science held launched in Houston in support of the "British in Texas" in the Nuffield Theatre of Southampton University on Sep- festival, and the craft will also be demonstrated in Morgan tember 1st. A film shown at the conclusion or the lecture City, New Orleans, Louisiana. and other Gulf Coast cities later admirably demonstrated the cnormous potential of the hovcr- in October and in early Novcmber. craft as a vehicle for usc in environments impenetrable by any The purposc of the demonstration programmes is to intro- other form of land or sea vehicle so far developed. duce the craft to potential users and to evaluate its perform- Mr Silverleaf, of the National Physical Laboratory. Feltham, ancc. Its applications include speedy transportation of personnel delivered a lecture on hydrofoils on this same occasion. He and cargo to ofr-shore oil facilities; harbour patrol and attempted with considerable success to give both a broad maintenance missions, such as those performed by the Coast explanation of the basic principles of hydrofoil flight and Guard; as an cmcrgency vchicle for fire-fighting, search and stability, and an "up to date" state of the art summary. rescue work at airports bounded by marshes and/or water; military missions such as reconnaissance and amphibious war- The Orkney Island Shipping Company has chartercd the fare; public transportation. forty passengcr Aquavion hydrofoil "Shadowfax" for passenger service in the Orkney Islands. A Ministry OF Transport pas- senger certificate has been granted. following a period of trials in the area, an unusually Grbulent corner of thc British Islcs. A syndicate of Australian and Japanese businessmen is She will be operated by a crew trained by the Aquavion tech- reported to bc planning to purchase a Japanese hydrofoil nical demonstration team. The craft was recently called out ferry :o carry passengers on Sydney Harbour. It is hoped at night to carry Mr David C~oat,a postman on the island that thc hydrofoil will be operating by the end of the year. of Papa Westray. to Kirkwall for urgent hospital treatment. Two types of hydrofoil arc reported to be under consideration The round trip was fifty miles. No other vcssel could have for use on the service. Both are made by the Hitachi Com- undertaken the rescue operation in the time available and pany of Japan. One model, the PT35 costs f125,OOO and aircraft were unable to take off owing to lack of night-flying carrics 100 passcngcrs, while the other designated PT50 costs facilities. f200.000 and has a capacity of 140 passengers. * * * An order for two hydrofoil ferries has been placed by the Wood's Hole, Martha's Vineyard and Nantucket Steamship Co, Massachusetts, with Atlantic HydroFoils Jnc, of Stony UNIVERSITY OF SOUTHAMPTON - Brook, NY. Research Fellowship The two hydrofoils will carry seventy passengers each at a speed of SOmph. The owners are planning a hydrofoil ferry Applications are i~lvited for a Research Fellowship for mainly cxperi~~ienlalwork in the Hovercraft field. Tlis value of the service during the summer of 1965. Fellowsliip will bc in the region of f1.200 per annum according The two ferries will be 60 ft long and will have submerged to experience. Applications. in duplicate. should be sent lo the hydrofoils manufactured by the Aluminium Co of America, Secretary and Registrar, Room 9. the University, Highfield, South and will have twin Cummins oil engines for main propulsion. ampton, giving the names of two referees by November 20th. 1964 * * * Some 200 gucsts. many from ovcrscas, attended a display of Hovercraft at HMS Aricl, Lee-on-Solcnt. on Wednesday, Mr Sidtrc,y C. Snrirh- Cox, September 16th, 1964. The occasion provided a spectacle ~vho\crrorc tlrc crrticlr unique in the history of HovercraTt. Westland demonstrated 1t~lric11crppcars orz pagc I6 the superb all-wcathcr perforrni~ncc of the SK.N3 and SK.NS of !Iris issrtc, is rn(tn(rgit~g by going out to sea in a 60 knot wind with waves 5 to 6 rt 4 director of P. & A. high. To the amazement and delight of all spectators, these Cnmpl~c~llLrd, who operate craft proved beyond any measure of doubt that Westland s~cclt?lc,rsc~rl~icc~s it1 tl7c Hovercrart are capable of successCully operating in appalling Llrisrol Cl~ur~trclut~d otz !Ire weather conditions. A Naval representative confirmed that no North Wolcs Coast. He is a conventional ship of equivalent size could have taken to sea clrtrrrcrcd ctccololrcrrrr ottd on this occasion. a Fc~llowof rllc Horels cttld The many Hovercraft on static display included exhibits Corcritrg It1s/i1ittc.He is (I from \Tickers HDL, Britten-Norman, and Westland. Guests r~rccgisrrctreof rlrc, Corrt~cy were able to inspect these craft under the experienced guidance of .Yomersc,~ctnd is ct of Company representatives, and British Petroleum provided clrcrirtnatr of rhc West of an indoor display of Hovercral't models. Etrglat~dTrrisr Lrd Of particular interest was the demonstration oC a radio controlled lj50th scale model of the Wcstland SR.N4. The Westlands have received an order for a 7 ton SR.NS from model capable of speeds up to 40 knots performed in wind Japan. The craft is scheduled for delivcry in early December conditions equivalent to 200 knots for a full-scale vehicle. and is being importcd by Marubeni Iida Co Ltd on behalf of Among tlie many distinguished guests present on this occa- Mitsubishi Heavy Industries Ltd, of Tokyo. It will be used sion were the Prime Minister of Tonga, and Sir Vivian Fuchs. for passcngcr carrying operations in the Kyushu area. Sir Vivian expressed considerable interest in the possible This latcst ordcr brings up to four the number of ovcrscas application of Hovercraft in anlarctic conditions. At a Press countries taking delivcry of the SR.NS, and sales negotiations Conference hcld after thc demonstration Mr Julian Amcry with other possible civil and military customers in several confirmed that the Government were considering the develop- parts of the world arc well under way. ment of a Hovercralt ship which would be required to furiction in tlie displacement mode as a conventional ship. and it was The SR.NS is a 7 ton hovercraft capablc oi carrying up to proposed at this stage to consider a vehicle having a retract- twcnty passengers or 2 tons of freight at a cruising speed of able keel. He said that industry would be invited to submit 70 knots. The craft is 38 ft long. has a beam of 22.5 ft, and is design proposals in duc coursc. Mr Amcry. who was accom- 15 ft high. It is powcrcd by a 900 hp turbine engine. Thc same panied for much of the demonstration, by Mr Shaw, or the engine is used to supply the power to operate the centrifugal ministry ol Aviation, a personality well known and respected lift fan which is 7 ft in diamctcr, and the four-blade, 73 ft ill the Hovercraft industry, went on to co~~gralulatethose rcvcrsi: pitch propeller. Control of the craft is achicvcd by responsible lor the development of HovercraCt. In the rela- rudders and elevators mounted on the twin-fin. tailplane unit, tively small period of eight-and-a-half years, Hovercraft have which opcratcs in thc slipstream of the propcllcrs. developed from the embryo stage to the sophisticated, reli- * * * able, wcll-engineered vehiclc. This. Mr Amery concluded, Derlr~y Hovercraft Ild have bcen studying thc long-term together with the demonstration was, indeed, :I tribute to the possibility of a fast 140 ton craft -- the D-3 - which would British Hovercraft Industry. be capablc of operating at 40 knots. Progress has bccn made in modifying the D-2 to ovcrcomc the problem or Iloating driftwood which tended to damage the vehicle's waterscrews when it was used during an cxperi- mcntal scrvicc on thc Thamcs last year. Thc vehicle's propul- sion units havc now been redesigned and sea trials of the modified craft will take placc imrncdiatcly the modifications havc bccn completed. So Tar Dcnny's espenditure has been nearly f400.000. Two additional glass-fibre hulls havc bccn built, and thcsc arc espcctcd to bc completely littcd out and commissioned as soon as the sca-trials of the D-2 arc over. On a cost-per-seat basis it is believed that thcsc three hovercraft will represent all attractive proposition to transport companies operating on inland and coastal waters.

Former Minister of Aviation, Mr Amcry. has informed thc Society or British Aerospace Companics that Britain will proceed with plans to develop an ocean-going "hovcrship". Speaking at the Society's annual flying display dinncr. Mr Amcry outlined the important part which the Government had played in Hovercraft dcvclopmcnt by ordering them for rc- search and cvaluatio~ipurposes, and said that thcy had now orderctl some for transport purposes as well. He said that they were consitlcri~igthe use of tlie cushion technique on larger ocean-going vessels ant1 were proposing. in conjunction with the Ministry of Del'encc. to invite industry to undertakc prc- lirninar!; studies aimed at thc pcssiblc construction of a hovcr- ship-a craft capablc of operating wit11 the flcct either as a displacement vessel using convcntional waterscrcw propulsion, or as a Hovercraft. A craft of this nature might well makc Tkc Pritnc Mitrisrer- of Totrgrt rrrrd Mr Jttlitrrr Attrcpry cstm~itli~rg a significant contribution to naval warfare. rr rctdio-cotrtrollcd ttrodrl of rhc Wesrlotrd SH.N4 cr/ the * * * Lee-on-Solent Hovrrcrafr displtry Mr Chris~opkcrC'ockcrcll sectz (11 ~Irc,Etigitrc,c,ritr,q /trd~ts/rics Associoriotr E.rhibiriorr ~vhiclz wc~slzeld it1 Lot~dot~from Ocrohcr 20 - 23. Hc is poitltitig tit a rnodcl of rlrc /r~clicd Hovrrccrr

A system using the air cushion principle for transferring Mr Christopher Cockerell, technical director of Hovercraft heavy loads from one level surface to another will soon be Development Ltd, a subsidiary of the State-owned National A introduced in Britain by Crorie Fruehauf Trailers Ltd. The Research Development Corporation. has announced that he system was introduced in the USA in April. ant1 rail. shipping hopes British Railways will lease about five miles of disused and air frcight operators have been investigating the low level track lor use in Hovercar experiments. A rnodcl ol' thc Hovcr- of costs the company claims for it both in terms of its own car is on display at the Engineering Industries Association opcration and in the saving of other expensive equipment. Exhibition. The principle of the "Freight Flyer" system is that air The Hovercar uses the hovercral't air cushion principle to cushions of a size proportional to the weight of the load to elevate itself about half-an-inch above a prepared track (which be transported arc fixed on the underneath of the container would probably be a shallow inverted V-form in concrete). or pallet. A modest volume of low pressure air supplied by Having no direct contact with the surface beneath it, a vehicle either a centrifugal or positive displacement blower feeds the of this type could be propelled at 200 - 300 mph by electric centre oC each air cushion, inflating the cushion to effect the linear motor or propeller. seal. The air supply can be mobile or fixed depending upon the A small vehicle carrying two people and test equipment distance that loads are to be transferred or transported. will be propelled along the five mile track at speeds of up to Power can be supplied by a small internal combustion engine 80 mph for the initial experiments. but in commercial opcra- or by an elcctric motor energiscd by either alternating tion a car weighing 100 tons and carrying about 600 people current or by self-contained batteries. might be used. Mr Cockerell has estimated that a track betwecn Lnnclon and Glasgow would cost about flOOm at current prices, using Westlalid Aircraft Ltd have concluded an agreement with prefabricated concrete sections. Autair Helicopter Services Ltd for the delivery of an SR.N5 to Canada in October. The craft will be used for a varietv of tasks including Arctic operations in collaboration with the A noteworthy feature listed among the shipbuilding loans Canadian Government. in Spain for I965 is that granted to Hyclrofoil Espaiiola, S.A., Another SR.NS has been ordered by Scandinavian Hover- Barcelona, for the first hydrofoil to be built in Spain. The craft Promotion Ltd who plan to eventually have ACVs for amount oE the loan is 9,593,472 pesetas. The repayment pcriod hire in Norway. Sweden and Denmark. is ten years at an interest of 5:; per annum. The loan covers 80% of the cost of the vessel less the amount corresponding The US Peace Corps has ordered a number of Dobson Air to the Government tax rebate to shipyards, understood to be Dart It's from Aircars Inc of Los Angeles. The Air Dart I1 996 of cost. is a fibreglass ACV with combined lift-propulsion power of The company intends to own three units initially and they 15 hp, and is an improved version of the plywood and vinyl will be given the names of Pitrlcr, Nitlo, and S~itlruMuria. The Air Dart which won the ACV races at Canberra in March. Pirita will have the following characteristics : length 18.25 m: Mr Harry Laufman, the president of Aircars Inc, was breadth 5m; draught in raised position 1.5 m; seating lor A recently interviewed in London where he stated that he had seventy-six persons; displacement 22 tons; speed of elevation concludcd agreements with a go-kart company in Britain to 22 knots, maximum speed 36 knots (65 kilometres per hour. manufacture the Air Dart I1 under licence. He has arranged Power: 720 hp gas turbine. Propulsion speed : 1,342 rpm. similar liccnce agreements in South Africa and Australia. Hull : aluminium alloy. Plan drawing of general layorrt of the "Deljin": I. Wheelhorrse; 2. Saloon for fifty passerrgers; 3. Cloakroom; 4. Buffet; 5. Compmlion way; 6. Storeroom; 7. Toilet comprtrtment; 8. Luggage store; 9. Engirleroom

DEVELOPMENTS IN-

HE June number of Ryechr~ogTransport, monthly journal type, was correct, and that she can be used throughout the T oC the Ministry of River Transport of the RSFSR (Russian year, i.e. when hydrofoil vessels are unusable on account of Union of Federated Socialist Republics) gives details of a new the ice. It may be noted here in the latter connection, more- hovercraft passenger vessel, tht: Dclfin (Dolphir~),to carry over, that a novel feature or the Delfin is that she is provided fifty passengers at a maximum speed of 140 km/hr (about 87 with wheels, which are normally lolded into the bottom oC knots), now being built at the Krasnoye Sormovo shipyard at the hull, but which can be lowered when required, e.g. when Gorki, on the River Volga. She is to be launched at the end running over unusually bumpy ice or terrain, to save the of this year, and should be ready for service by next summer. hull from being damaged. These are sprung in such a way Designed by the Soviet naval architect Valeriy Schoenberg, that they yield gently when some extra hard obstacle is en- chieC constructor of the Krasnoye Sormovo shipyard, in con- countered, returning into position when that obstacle has sultation with experts at the "N. Ye. Zhukovskiy" Central In- heen negotiated. This fitting will come in useful where the stitute of Aerodynamics, this vessel is of the air-cushion type, vessel is used in places such as abound in Siberia, to which and embodies experience gained during 1962-63 with a very access by river is made dificult, 01 impossible, by the shallow- similar vessel oC smaller dimensions, the Radrcgu, also designed ness of the water, and roads are non-existent, a fact which and built at Gorki, which gave every satisfaction in service on might usefully be noted in. for instance, Canada. the Volga last summer, and with a smaller vessel ol the side- As will be seen rrom the accompanying plan drawing, the wall type, the Nerrr, designed and built at Leningrad. She is general layout ol the Delfirr has been conceived with the designed primarily for inter-urban services on inland waters, object of providing for the comfort oC the passengers in respect over distances of the order of 400 km (250 miles), and the of noise from the engine, which is considerable. The engine decision to proceed with her development is based on the and propeller unit are situated right aft, well separated from - fact that experience with the Radrlgu proved that the esti- the passenger saloon, forward. by two soundprool bulkheads, mated reduction of transport-cost per passenger of about 30"A, enclosing a cloakroom, a buffet, a toilet-compartment, a first- as compared with that of a hydrofoil vessel of the Ruketa aid post and a baggage-store. Forward of the passenger saloon, The Soviet Hovercroft "Rodrrgc~"secPrz or1 rhc Volga SOVIET HOVERCRAFT Commander Edgar P. Young R.N. Retired

This is an aircralt-type jet unit, Type AI-24, designed by A. G. Ivchenko, developing 1,800 hp coupled through a distributing and separated from it, is the wheelhouse, with excellent all- gear to the reducing gears ol the compressor for the lifting jets round vision, lrom which the main engine, and its ancillaries, and the t\vo airscrews. mounted abafL it, both oC 'ivhich have are remote-controlled, and the rudders are hydraulically oper- adjustable rotating blades, to provide for alterations of the ated, and which is equipped with such a wealth of naviga- disLribution oi: po\ver between them. When the hovercrnlt is tional aids that the vessel can be operated with complete running over smooth water, or any other very smooth surl'ace, sal'cty at night or during thc dark periods of the year which and the minimum hover height is required, maximum power occur in the Arctic. is diverted to the air screw, with consequent achievement of Tlrc, prirlciptrl por~icrrlc~rs{ire rrs follows : maximum speed. When the surlace is :I rough one, however, Weight (l'ully loaded) : 11.75 tons greater hover height is required, with consequent greater Length overzlll : 26.5 metres (about 87 It) diversion or power to its maintenance and, ipso foclo, the Breadth moulded : 10 metres (about 33 ft) speed is reduced. This engine, though occupying relatively Draught when watcr-borne: 32 cm (about 1 ft) little space and being relatively light, is about ten times as Height: 6 metres (about 20 ft) powerful as the piston engines used in earlier Sovict hover- Hover height: 20-30 cm (8-12 in) craft. The vessel is steered by four aerial rudders, mounted SurCacc area of bottom: 165 sq metres (1,778 sq ft) abaCt the two airscrews, which are hydraulically controlled Pressure of air cushion: 200 kg/sq metres (4 Ib/sq Et) from the wheelhouse. Speed (maximum) : 140 km/hr (87 knots) In order to reduce weight to a minimum, the hull and super- Speed over rough surfaces: 60-80 km/hr (37-50 knots) structure are made of light alloy, the latter being designed on Passengers : Firty the lines oC the fuselage of an aeroplane, to reduce air- Crew: Two resistance. Ballast-lanks are fitted, for trimming purposes, and The Dclfirz differs from most hovercraft in the USSR or in there are the usual systems ior pumping, sanitation and fire- other countries in having only one engine to provide power fighting. Fire-resistant synthetic materials are used for the both for main propulsion and for creating the air cushion. furnishing and decoration. A NEW TYPE OF ENGINE FOR HYDROFOIL VESSELS

Engineer Yu. A. Bordovitsyn

HE effect of rolling and pitching on passengers and crew It is obviously doubtful whether a gas turbine with reduc- T of a hydrofoil vessel is minimum when the wave-height is tion gear, mounted in a hydrodynamic pod can be used for less than the clearance of the hull. In such conditions, a high speed vessels with super-cavitating foils, because, as has vessel fitted with controllable foils can develop her full speed been remarked earlier in this article, the resistance ol pro- with minimum acceleration of her centre of gravity. It is not truding parts constitutes an important part of the total resist- possible to fit smaller types of hydrofoil vessel with very large ance. The propulsion unit of this type proposed by V. Yu. struts Cor the loils, as this would reduce their stability too Tikhoplava is therefore suitable only for medium-speed vessels much, so it is obvious that only vessels of larger tonnage of large displacement with deeply-submerged, automatically can have the requisite sea-keeping qualities. controlled roils, working in sub-cavitating conditions. This is At the time when a hydrofoil vessel is becoming foilborne, the opinion arrived at by Engineer A. N. Vashedchenko also she is subjected to what is called the "hump of resistance", in his article on "The New Type of Engine and Sea-Going which is practically equal to the resistance at full-speed (not- Hydrofoil Vessels", in Sltdosrroyeniye No 9, 1962. It must be withstanding that the latter is two to three times greater than borne in mind that the great length of the fuel pipes and the d the speed at which this "hump" is encountered). The propul- considerable wastage of working gases must inevitably cause sion plant must, thererore, provide sufficiently large thrust in an increase in the loss of pressure in both the leed and the both cases. It is particularly important that the thrust shall be exhaust pipes, and that this affects the power and the fuel capable of increase to ensure the quick emergence of the vessel consumption of the proposed unit or calls for an increase in on to her Coils when there is a high sea, so that the shock the diameter of the pipes which would increase the total or the waves on the hull at that time shall last for as short resistance of the vessel. a time as possible. Hydroloil vessels may be classified accord- The power required for larger and faster hydroroil vessels ing to their loils, either as those with non-cavitating foils, or can be obtained only by the use of a gas turbine unit of as those with foils working in fully cavitating conditions. For which two types have been developed for this purpose: a gas vessels of the rormer type, with speeds of up to about 60 knots, turbine with bevel transmission, driving a super-cavitating the resistance encountered is mainly that due to the foils (that propeller, and a gas turbine driving an airscrew. The hydro- due to the struts and other projecting parts accounting for dynamic qualities of a hydroloil vessel with propellers work- only 15-20", ol the total). At the speeds at which they go, ing in sub-cavitational conditions are practically the same as the resistance ol the loils varies only slightly, remaining steady those of one with an airscrew. In the former case, however, at about lo";, ol the displacement, but that of the struts in- transition into a condition of greater cavitation with the creases in proportion with the square of the speed. increase of speed causes more rapid deterioration ol the hydro- The use ol super-cavitating foils permits ol the development dynamic qualities than that which occurs in the latter case, or greater speeds with only moderate increase of foil-resistance, caused by the resistance of the airscrew. but the resistance of the struts and other project parts repre- The use of super-cavitating propellers is made more difficult sents about 5"(, ol the total resistance, and may reach as much by the fact that at low speeds the propulsive power of a as about 205 of the displacement. super-cavitating propeller is extremely low, which means that The most promising types ol sea-going hydrofoil vessels, the propeller cannot develop the high thrust required to raise and those which make full use ol all the advantages of the the vessel onto the foils. It considerably increases, rnorcover, hydroroil, are high-speed vessels of large displacement with the complication and the weight of the propulsion unit. their loils working in fully cavitating conditions. In an article by V. Yu. Tikhoplava, published in Sudo- The airscrew, on the other hand, being directly connected stroyoniyc No 1 I, 1961, the essential requirements of the pro- to the engine, requires no cumbersome shafting, or bevel trans- pulsion installation of a hydrofoil vessel were specified as mission gear, and so on. The diameter of the propeller used follows: low specific weight, great efficiency, high propulsive must be very large, however. That required for a twin-screw horsepower, simplicity, and reliability. To these should now be installation must add up to little less than the breadth of the added that it must develop increased thrust at low speeds, so vessel, and this in itself makes airscrews unsuitable for use in as to lift the vessel on to the foils quickly. hydrofoil vessels, quite apart from their susceptibility to the When it comes to the actual choosing of the type of power effects of spray and wash. unit and the system of power transmission, many factors must There is reason to believe, however, that in certain condi- - be taken into consideration. such as the type of vessel and tions aircraft-type turbo-reactor units, and especially those the service for which it is intended, the region in which it is with a double-chamber, could be used in high-speed hydro- to operate, and, of course, the displacement and speed. foil vessels. Aircraft engine building has now become very successful. sp.d.. The double-ch;~mberturbo-jet unit TKDD, Typc ITZD-I, lor \4$4- ,c'. instance, ;IS used in the Boeing 707-1208 passenger liner, is oliicially reported to have a specilic fuel consumption at full- - power of 0.68 kg,'Lg thrust per hour and a spccilic ucight of 0.27 kg,'kg thrust. The rclative air consumption through the ,F4,,. Jpe,ld sccond chamber is 1.4. With an incl-case of this value thc flow from the exhaust nozzle of the sccond chamber decreases w continuously. which leads, as can be seen from the attached 0.9 graph (I) to a reduction of thc specific fuel consumption. The incrcasc of horsepower combincd with the rcduction of the spccd of outflow in thc sccond chambcr leads to a retluction 0.8 20 in the spccifc fuel consumption (2). It would be possible to design for a hydrofoil vcssel a double chambcr turbo-jet unit 0.7 of this typc which would bc compctitivc, so far as spccific fuel consumption is conccmed, with a gas-turbine unit driving an 0,6 airscrcw or a marinc propeller. Elfective steps could be taken to minimise the amount of sea water which passes into the air-intake, and to reduce '?5 noise, with the result that such an engine could satisfy all the requirements lor a propulsion unit for high-speed hydro- 0.4 0 7 2 roil vessels. (1) Parameters of the working process: Cheflicient of increase ol pressure in the compressor Deperlde~tce of the specific thrust artd specific frrel co/zsrtrnp/io/~ of the 1st chamber. p = 6.0 ort the dis/ribu/io~~of air bc/rvecri 11le first a~ldscco~id cl~arnbcrs Coeficient of heating ol the air in the first chamber. D = 4.0 Fraction 01' the work transferred to the 2nd chamber for 1 cycle. x = 0.5 Ratio ol compression to expansion of the 1st and 2nd

chamher q -: q = q = 51 = 0.85 SI r1 SL I'? (2) B. S. Stechkin. P. K. Kazandzha, and others, Tlze theory of jc.1 c,rzgir~csworkirtg proccPss und cl~urr~cturistics.pub- lished by Oborongiz, 1958.

HYD ROTOIL PAJSENGER SHIP "KOMETA" Length - 35.12 m Mo~tldedhr~adth - 9 6 rn Servrt c horse-powc,t of mairl engines - 2 X 9.50 hp

Sc,/ vrc (. sp~ed- 34 krzots ~Vut)zb~rof yac \engcJrA - 1 IS HYDROFOIL --r -- r '#. " PASSENGER SHIPS

'E - AND RUNABOUTS ARE EXPORTED BY VSESOJUZNOJE OBJEDINENIJE

MOSCOW, G-200 US S R Development of

Anti-Cavitation Erosion Alloys 1

Chemical Composition (%) Cu Zn Mn Fe A1 Ni Sn Be I Mn-Bronze ...... 56.83 38.68 0.76 0.89 0.98 0.35 0.47 - Al-Bronze ...... 80.90 - 1.41 4.82 9.68 4.86 - - Cu-Al-Be Alloy ...... 90.72 - - - 8.33 - - 0.93

Table I. Chemical Cornposiliorts of MIZ-Bronze,Al-Bronze and Newly-Developed Cu-A/-Be Alloy

s materials for the marine propeller, Ni-A1 bronze or the alloys conventionally used as marine propellers (man- A Mn-A1 brome have lalely come to be used extensively. ganese bronze, aluminium brom), particularly in respect to These alloys, as compared with manganese bronze hitherto their mpedive rnechauid propadk~ and anti-cavitation- used, provide greater resistance to erosion and greater strength. erosion reatance, lows tho fdowing result: These aluminium bronze alloys, however, are more or less Table 1 rhows tho chemical cmpmifion, respectivdy, of a easily affected by cavitatlon-erosion if used on a hydrofoil spechen of the newly-deveIoped Cu-Al-Be alloy, and the boat, the propellers of which have greater numbers of revolu- conventional maaganese bronze and ahnnlniura bronze hitherto tions, or large-size ships, the propellers of which similarly have used far marine propellens. a greater rotational speed. In recent years there is an evident Figure 1 indicata the mechanical properties, respectively, tendency for the size of ships to become larger and larger of the three alloys listed in Tabie 1. and the speed greater. In view of the circumstances, it is inevitably desired that a material provided with a better resis- Figure 2 refers to the results of a test conducted on these tance to cavitation-erosion than aluminium bronze be made three alloys in respect to their respective resistance to cavita- available. tion-erosion, on a magnetostriction vibration system cavitation- In order to satisfy the aforementioned requirement a series erosion testing apparatus having an oscillation frequency of of search of adding beryllium to copper alloy, giving a higher 6,000 cycles, output 100 w, and amplitude 1%. property of precipitation hardening, has been conducted, and The newly developed Cu-Al-Be alloy as shown in Figure I through these experiments a new propeller material, equipped is provided with these properties: tensile strength 70 kg/mmp, with a hiaer rigidity and an improved resistance against elongation : 16%, impact vahm : 5 lqgn/cma, hardness : 180H; cavitation-erosion, has been developed. and thus it is proved to have better mechanical properties than This new material is an alloy which contains in the base manganese bronze or aluminium bronze, metal of copper, 4.0 - 9.8% of aluminium and 0.04 - 2.5% of At the present moment, experiments arc being carried out beryllium, and, besides, its chemical composition is such that on a hydrofoil boat equipped with actuaI propellers made the ratio in weight of aluminium and beryllium content is respectively, of the three alloys listad in Table 1. The experi- more ban 4.0. ments so far undertaken amply attest to the superior properties A comparison between the above-rnenfioned Cu-AI-Be and possessed by the 0-Al-Be alloy. It may be added that a patent application is now pending for the Cu-Ai-Be alloy.

. . - ---- .. .- --- .- - ~ .- - . ---A- ...... - >

80 230 L~

70 210 so- 1 -- -- :! . rn 190 -" -g .byl 110 z l :: B L*:3-E rn IW -E 1-a - E!f an IN.!I, . 2zt 110 rl (2.54) I0 w

0- 0- 70 I Mn-Brome A CBroms New IyDe~eloped ~rr~lmm ~mmlm ~t,-Dcunl~ CtrAl-Be Alloy 7- ,I- Clc-llPy - d dY Figure I. Comparison ort Mechanical Properties of MI+ Figure 2. Coinparism on Cavftarfbn Bosion of Mn-Bronze, Rro~lzc,A/-Brortze arzd Newly-Developed Cn-Al-Be Alloy. Al-Bmze and Newly-Developed Cu-A]-Be Alloy LEOPOLDO RODRlQUEZ SHIPYARD MESSINA - ITALY

Licensed by Supramar A.G. Zug-Switzerland The Greatest Experience in Figure 3. Micro Slrirclure of Newly-Developed Cu-Al-Be Hydrofoil Boat Building Alloy (X200)

RODRIQUEZ Hydrofoil Boats Across The World's Seas in 15 Countries

4 \

Mrrgr~c~/o.s/ric/io~~T'ihrtrtiorz S~stemCavilariorr Erosior~ Tesl- irlg Apptirlrlrr~,showirrg, from left 10 right, sttrAilirrr, nr~iplifier (rrtd plrose corrlrol circrril, nlrrgr~clostrictior~vibrator

Cc~vilcrtiorrI:ro.siorz Tcstcd .Ypccinrrr~s: ANY KIND A. Ncwly-dcvc,lopcJ CII-Al-Be Alloy n 13. Alrrt~rirrictm 1jroni.e of C. Morlgtrrlcse Brorlze SHIP REPAIRS A Note Concerning Cavitation on Hydrofoil Propellers by I. Eggestad Scientific Officer at the Norwegian Ship Model Experiment Tank Figure I I

I covrJLe ol years ago, the Norwegian Ship Model Experi- Relative air content in the tunnel watcr during the tcsrs. A ment Tank (SIMT) was asked to seek the reason For severe a I measurcd with van Slykcs apparatirs was - = 0,15. blade root cavitation on a hydrocoil boat propeller, shown a; in Fig. I. l'he hydrofoil boat concerned has a displacement of sixty tons fully loaded, and is equipped with two propellers Torque and thrust properties werc checkcd in the usual way I each driven by 900shp at senrice speed of 34 knots. The by plotting K and K versus speed of advance J, and these Q T propellers very often had to be replaced arter only 300 hours \ service. characteristics show normal trends for the degree of cavitatio~i which appear at Lhis condition, Fig. 3. The propeller elliciency The propeller rala are: q = 0,64 a1 servicc speed = 34 knots was also found satis- Diameter D = 770 rnrn factory. Face pitch at 0.7 D = 1,013 mrn The extension oC caviation at various angular positions ol Pitch ratio (P/D) = 1,315 the blades lo the Coil was thoroughly investigated. Besides the 0.7 rather pronounced tip vortex cavitation and partly sheet Blade area Ae/A = 1,OO cavitation, fluctuating cavities appeared at the base oF the Number of blades Z=3 blades. Any steady blade root cavitation was not observed. A model set-up was made, including half the aft foil with However, there was a marked tendency to cavitation at 4 shaft bearing and rudder (Fig. 2). The propeller was mounted the bearing sleeve on the foil, which undoubtedly influenced on a shaft with inclination cqual to that on the full-scale the fluctuating bubbles mentioned above. Furthermore, cavi- craft. This shaft was attached to the driving shaft in the tation was evidently formed also in the clearance between ! watcr tunnel, by a ruddcr tubc "urlivcrsal" coupling of propeller hub and bearing, that, like the cavities travelling sullicient strength to withstand thc torque and thrust of the from the upstream end of the bearing sleeve, also created a propeller model. The cavitation number, based on the relative sort or blade root cavitation. P-P,, After these statements it was decided, firstly, to elongate. speed or propeller blade section at 0.7 D is OR = f~ VRP and make it much more streamlined. Finally, the space between slzeve and propeller hub was closed with a thir~walled tube. for the condition which should be investigated. but still allowing the propeller to move somea~liatin asial Reynolds number for model propcllcr. based on water speed direction. at section length a1 0.7 D was on an average RI~= 1.27.10(;. These alterations enected the ca\litatic~n appearance in a

, PROPELLER SHAFI 1 I BEARIAIG SLEEVE 1 1

I AFT FOIL \/ RUBBER TUBE 1 -$----- Figure 3 Figure 4

rather remarkable way, Fig. 4. Fluctuating cavities no longer IC the simple alterations reported here improve the lull exist near to the blade root, and also tip vortex cavitation scale cavitation condition to such an extent as should be seems to be less pronounced, probably due to a more steady expected from the test results, one cannot be too carelul in Ilow around the bearing sleeve and consequently an improved designing upstream constructions to the propellers lor high wake distribution behind the foil. speed craCt.

Licensed Shipyards : Cantieri Navali Leopoldo Westermoen Hydrofoil A/S Wykeham Supramar Hitachi Shipbuilding & Rodriquez. Messina/ltaly Mandal/Norway Hydrofoil Ltd, London, England Engineering Co Ltd, Osaka/Japan by S. C. Smith-Cox C.B.E. Chairman. Hovertransport Ltd

or 30,000 if you include the chimpanzee. lime as a relief or standhy niachine, operated 011 all or part 29,999, From June 17th until September 1st. Hover- of thirty-six days. Both machines operated together on nine- transport Ltd. operated a Hovercraft service teen days. The service was suspended lor weather reasons across the Solent between Eastney Beach at Southsea and for two-and-a-half days only and lor mechanical reasons on Appley Tower at Ryde. During the period 28,800 passengers two complete days and six separate half days. These figures were carried on the crossing, but including those who journeyed show a very considerable improvement on those obtained in between Cowes and Southsea, and in reverse, when the craft the Bristol Channel in 1963 and have certainly confirmed, so started and finished ~tsday's run, Lhe total number was far as I personally am concerned, my faith in the future of 29,999. In addition, one ch~mpanzeefrom a local Zoo was this type of craft. carried and thus the 30,000 was reached. Statistics can be boring, or they can be thrilling. Those The service was planned to give nine crossings each way operating the service viewed the latter alord as the right one each day with the SR.N2. In practice these were augmented, when on five days during the period over a tllousand passengers \vhcn occasion demanded, and on days when the SR.NS was were carried. Top day was Thursday, August 27th, when 1,431 u. in operation as many as twenty crossings in each direction people crossed the Solent on this Corm of transport. On this were made. day, N2 made twenty-three crossings and N5 twenty-sis. P. &: A. Campbell Ltd (a subsidiary company of George Second best was Thursday, August 20th, when 1,353 passengers Nott Industries Ltd) had operated a service with the SK.N2 were carried; the N2 making twenty-two crossings and the in the Bristol Channel in 1963 and being one of the companies N5 twenty-seven. interested in Hoverlransport Ltd, it can be said that the 1964 A feature of SR.NS1s participation was its continuous opera- venture was a logical cont~nuationof the one operated in 1963. tion on several occasions lor as much as nine hours in a day, During the scheduled period, the service in fact operated without the engine being stopped. This reliability in a craft on fifty days, either during the whole or some part of the which is the first of its type and which had been launched day, and in almost every case during the whole day. Of those only two montlls previously, indicates the technical strides fifty days, the SR.N2 operated on all or part of thirty-three since 1963. days and the SR.NS, which was used for a good deal of the To facilitate the handling of passengers, barriers were erected on both beaches, together, in the case of Southsea, publicity and help given by the newspapers was phenomenal. with not only an enquiry office, but a Curther sma[l kiosk for Reactions to new foms of transport are always interesting, the sale of souvenirs. Passengers on arrival were told by which as indeed are reactions to almost anything new in life. Con- journey number they could travel; issued with tickets accord- versations with passengers on the crafts and leaving them, ingly and returned to take their places on the cralt some ten showed a complete satisfaction with this new Form of trans- minutes prior to departure. Enclosures into which passengers port and indeed a great deal of enthusiasm for it. The fare Tor each service were moved were erected on the beach, and was 101- in each direction, but this proved no deterrent and a number of chairs for pelsons who wished to watch the during all except the last two services oC the day, the crafts operation were provided. Similar arrangements, on a slightly ran full to capacity. By the end of the service, numbers of smaller scale, were in operation at Ryde and except for the business people were using it between the Island and the main- fact that a string of buoys were. laid to indicate the approach land, and the experiment as a whole proved a major success. line oT the cralt on the Ryde side, no further work on the Experiments are one thing: planned transport, services another, ground had to be done in connection with the service. and these crossings of the Solent were the second in the series The issue oC tickets, control of crowds and general hand- of operations designed to get the necessary data to provide the ling of passengers was done by a slalT ol' live on either side. craft necessary for commercial operation. The information One cashier, three beach staff who were Tor the most part gained during 1964 has encouraged those who are concerned students on vacation, and one beachmaster. In addition, a full with the operation of Hovercraft, and every effort is being time Manager Tor the service was seconded from P. & A. made to speed the time when cralt carrying both cars and Campbell Ltd in respect of the Southsea side and a similar passengers in large numbers will be in operation across the oficial I'rom Britten-Norman Aircraft, from the Isle of Wight. Solent. A total expenditure of approximately fSOO was incurred in OC 1965 it is as yet dificult to speak. Sullice it to say that, advertising the service, by means of handbills and posters if possible, the service will once again be in operation across throughoul the Isle of Wight and in particular in the Ryde the Solent, thus ensuring that the goodwill built up in 1964 area and also on the Portsmouth side of the Solent. News- may be increased until finally a planned full scale service paper advertisements opened the service and the amount of comes to fruition. PRACTICAL EXPERIENCE WITH THE POWER UNIT OF THE HYDROFOIL MOTORBOAT ccVIKHR" A Ale kseyen ko Chief Engineer "Vikhr"

The "Vikhr" is n hydrofoil built at the Krasnoye Sorrlzovo Shipyard, Gorki, on the River Volgu, and can clcconlrno- (late 200 - 300 passengers. She hcrs cl cruising speed of about 50 knots, ~tldN range, at that speed, of about 500 r?riles. She as cor~iplote~Iit1 the late surnt77er of 1962. ltltended prirnarily for use at sea, rcither than on rivers, she has been running regulur services in the Black Sea, and is reported to ha1.e provecl very srrtisfnctory, even in rorrgh weather

HE llydroloil motorboat Vikhr, an experimental proto- Fig. 3 shows the outer and limiting characteristics. To T type vessel for carrying 260 passengers, has been in facilitate analysis, these are related to the propeller character- regular service in the Black Sea, in various sea conditions on istics obtained in practice in various conditions and constructed the lines between Odessa and Kherson and Odessa and Niko- in the manner described. layev during the autumn of 1962 and the summer and autumn Let us consider now the more usual working conditions in of 1963. which the power unit of the Vikhr may operate. Her power unit consists of four diesel motors Type 150-F-4, each developing a maximum of 1,200 bhp at 1,850 rev/min, Case 1 : and a nominal 900 bhp at 1,600 rev/min. She has four pro- Hull and Coils in clean condition; propellers not cavitating; pellers. 260 passengers aboard; no waves. The rollowing is a survey of the working of this power unit The normal propeller characteristic corresponding with these in various sea conditions, and with various conditions for the conditions is as shown in Fig. 3. The vessel becomes foil- hull and foils. borne in Section B of this characteristic with some transler For purposes of analysis, it is assumed that the regular according to the limiting curve. characteristics of the engines are all the same, and that this The character of this section depends entirely on the rapidity - applies also to all the propellers. In such conditions it would of the build-up of the number of revolutions. Point A corres- be correct to assume that the relative torques of all the engines ponds with the nominal condition of 900 bhp at 1,600 rev/min, are equal with maximum power in reserve. This is the condition in which river hydrofoil vessels with similar engines and propellers normally work. Case 2 : Two hundred and sixty passengers aboard; propellers not where M is the torque of engine i in the assumed conditions cavitating; no waves; deposits on the foils of 1-2 mm of salt; , and on the hull. of 8-10 mm of barnacles and weed. where M' is the torque of the same engine in nominal condi- Deposits of this nature occur during June, July and Acgust n if the vessel is running for eight hours in twenty-four, or lies tions. at anchor for a fortnight. Equality ol these relative torques is fundamentally essential The effect or these conditions on the normal working ol lor the working of the engines in parallel, since it provides for the power unit can be discovered by adding the propeller equal distribution of the load among them. characteristic for a foul condition to the normal characteristic. The following method has been adopted for expressing the Fig. 3 shows that the propeller characteristic is considerably working characteristics of the propellers. steeper than usual and that at 1,60Orev/min it reaches the If it is assumed that hourly consumption of fuel is directly outer characteristic. The point 0, at which the propeller proportional to the travel of the shaft of the fuel pump, one characteristic intersects the limiting characteristic, lies to the can arrive at a relationship between the hourly consumption left of the point 0, which means that overloading occurs of Cue1 and the travel of the shaft of the fuel pump at every earlier, and at a smaller number of revolutions per minute, number or revolutions per minute lrom slow speed to full than it does in the conditions described in Case 1. The power speed (see Fig. 1). overloading in this case is When constructing the graph shown in Fig. 1, the maximum hourly consumptions of fuel with the fuel pump shaft in the N ---- N "limiting" position have been taken from the outer factory D A qo/, = - 100% = 25.6% characteristic shown in Fig. 3, and the minimum hourly con- N sumptions for the same number of revolutions per minute, A from their relationship to the travel of the shaft. where N is the limiting power in foul conditions, and N is Fig. 2 shows the curve of the change of the relative con- D A sumption of fuel according to the number of revolutions per the nominal power. minute, as recorded on the test bed. If the position of the Working in such conditions is not permissible. fuel pump shaft and the number of revolutions per minute at Bearing in mind the high degree of lorcing of the type of - a given time are known, the hourly consumption of fuel can engine with which we are here concerned (its specific weight be taken from Fig. 1, and the power developed can be deter- g 1.7 kg/hp), it is essential to be particularly careful to avoid mined from the relative consumption of fuel. any overloading. Figlire I. Graph show it^^ the relurionship be- Figure 2. Graph showitlg the relationship twcol thc horirly cot~srtmptionof fuel trnd the between the relative con sump riot^ of fuel and trcrvcl of the frtcl primp shaft the number of revoluriot~sper mitzrrtc

roo l I I I I I I I I I/

No. OF REW~MIN. If the effect of the wave is more prolonged, the engine will begin to lose revolutions along the outer chracteristic until the vessel becomes a displacement vessel. The overload due to the shock of a force 5 wave is N ---N

A I - 1850; 2 - 1700; 3 - 1600; 4 - 1500; 5 - 1400; 6 - 1000; where N is the maximum power under the shock of the 7 - 1200; X - 1100. Thc figrires I - X relutc to rcvolrrliorzs c wave, and N is the nominal power. pcr rnitlrrte A Such conditions very seriously reduce the reserve of power. since the overloading is of a cyclic character. The foregoing analysis affords a fairly clear picture of the regimes of the power unit of the motorhoat Vikhr and makes it possible to The method indicated of determining the load by the posi- arrive at the conclusion that sea-going hydrofoil vessels must tion of the shaft of the fuel pump makes it possible to choose have a power unit of sufficient power to be able to work at a working regime which does not overload the engine. It is a regimes below the limiting characteristic. particularly good thing to determine the weighting of the propeller characteristic on account of fouling of the foils. Fig. I shows the point at which nominal working - the posi- tion of the fuel pump shaft and the number of revolutions per minute - is regained after cleaning (with no waves). ('omparison should be made, with the engines running at the same number of revolutions per minute, between the positions of the fuel pump shaft before and after the foils have been cleaned, and if any overload is ohserved, the power unit qhould not be run until the periodical cleaning of the foils has been carried out.

Ctrsr 3 Hull and foils clean; 260 passengers aboard; propellers not cavitating; waves force 5, with 3"" security. In these conditions, the propeller characteristic will be heavier than usual. It will be impossible, however, to con- struct this on account of constant changes in the position of the fuel pump shaft. The analysis must therefore be done by comparison. Let us assume that the vessel has risen on her foils inside the harbour and is proceeding to sea. The regime of the power u.lit is shown by point A on the normal propeller characteristic. Draw through this point the regular character- istic CE (see Fig. 3). Suppose now that the vessel has experi- enced a momentary shock from a wave of force 5 (while running, such shocks were of a more or less periodical character. according to the character ol the waves). In such circumstances since the position of the organ for tuning the corrector remains unaltered, point A on the propeller charac- teristic nroi,es along the correcting curve to point C on the ~cMP outer ch.lr:~cteristic. TRAVEL OF FUEL UFI- m.m.

Adapted tmnrlolion from the Russian of an article in the Soviet Jo~rrnal"Morskoy Flot", No 9, 1964 The Determination of the Stability of Vessels on Shallow-Su bmerged Foils Engineer B. A. Tsarev

The hydrodynamic rightinp: mompnts on suhmrged hydrofoils result frm The Lift Coefficient at a giver, relative depth of immersiorl of. the the increase of the lifting power of the foil subject to the following foil C+,j is linked up with that of the same foil at an infirilte conditions: - depth by the following formula

( 1) If the rtlative depth of imersion is increased, H = H/h where ti is the immersion, and h is the chord of the foil (Fig.la). (2) In practice, this concerns only shallow-immersed foils, with tl ( 1 (Fig.2); 'he magnitude of the coefficient lii found by experiment, is shorn (2) If the submerged area of the foil, S, is increased on the side in Fig.2. The actual formulae (1) and (2) lead to a somewhat cumhersome to which it heels, and is reduced on the opposite side (Fig. lh) solution, for which the following, more simple, alternative is recommnded. in vessels whose foils cut the surface of the water (this relates principally to V-shaped and "stepped" foils, though in the 0.5 latter case the relative depth plays an essential role); (3)

(3) If the angle of attack (a) of different parts of the foil or the flaps is altered (Figs. lc and d). The proposed formula (3) is convenient for making calculations and alterations and requires no supplementary materials other than the two From a theoretical point of view, the most interesting problem to he lower scales of an ordinary logarithmic slide-rule (the bottom sc_ale studied is that of the righting moments on shallow-immersed foils. showing the values of R and the second from the hottm, those of 1W). Since the absolute value of these is less than those on foils which cut the surface, the methods of calculating them must he more accurate. 'he Research mrk in relation to the transverse stability of shallow- practical importance of having reliable methods of calculation arises suherged foils has been done hy G.A. Goshev (3) who has proposed the from the fact that all our (Soviet) hydrofoil vessels use shallow- following formula for a stipulated metacentric radius, ensured by a imrsed foils, either alone, or in combination with various auxiliary separate foil or element of a foil devices, such as elements of V-shaped foils. 4

Practical formulae for estimating the stability of systems of shallow- submerged foils are given below. where Q and Yi are the metacentric radius and the lifting force of The lifting force of a foil (or of part of a foil) which is slightly a separate foil or element of a foil; suherged may he determined hy the following equation D is the total weight of the hydrofoil vessel.

'he coefficient yi is worked out in his treatment (3) in the form of a graph. Analysis of the numerical values of various points on this graph shows that the coefficient where q is the density of the water; yi is linked constantly with the magnitude of Jfi in the relation v is the speed of the vessel; S = 1 x h is the area of the foil (or part of the foil); 1 is the span of the foil; h is the chord of the foil.

Formula (1) shows that at a constant speed the change of lifting force depends on A , S and A . Moreover, in systems without artificial control, it is possible to change H only, in the case of shallou- immersed foils, and S only in the case of foils cutting the surface of the water.

Figrirc I. Drawings showing the development of righting Figure 2. The effect of relative immersion on the coefficient moments for different foil systems of iifting force becomes ------" = ;i AH, - zg h0 1 - 1' Mu, D

'he mo~itudeof Z is found from calculating the load, those of 011 are geometrical chgaracteristics and are determined by the drawing 2 of the deposition of the foil structure. ?he magnitude of q, for aq ordinary flat, undivided foil is determined by formula (7).

For other types of shalloa-irmersed foils the following fcrnular fsr I, q may be obtained.

(2 (a) for a foil with adihedral (see Fig.4a) if a small allowance fcr 6' safety ismade, and if the effect of the dihedral on stability is - i pored on' - i -- 5-t % 9 (h) for a divided foil (see Fig.4b) 11 t- 4c' Figure 3. Plan for the determination of metacentric height of hydrofoil vessels For divided foils, the supplementary role of the small flaps under the foils (see Fig.4~)is quite in conformity with formula (12), but for practical purposes it is more convenient to express by means of Thanks to equation (5) it is possible to find without reference qi 0, other characteristics (the dimensions of the foil) to G.A. Goshev's graph. In particular, by using formula (5) one can arrive at

Formula (12) may be used also for calculating the areas of the hori- zontal elements of twin ladder foils (see Fig.4d). It is reasonably safe to assume that 5/4R 0.1 and then

1. The formulae proposed make it possible to calculate simply and + 'he points of application of the lifting forces of the foils (Fig.3) rapidly the characteristics of initial stability of a vessel with any are in most cases situated below the reference plane and in practice systemof shallow-suher4 foils, and thus to establish the disposition are characterized by the distance from the plane OH or from the of the foil structure from the point of view of stability in the fixed point OHi of the foil (for non-horizontal foils) from the preliminary stages of design. reference plane of the vessel. 2. Making calculations by means of these formulae requires no auxiliary materials, and the data for a foil structure may be given in the form AH. 14% z D zc of preliminary sketches, so that the method of calculation which has been described In appropriate for the variational analysis ofanynumber of variants of foll structure and its ~ositionin relation to the hull. OH belongs to the foil system as a whole, AH, to a separate foil (or part of a foil). Thus the fonnula for calculating the initial stability 3. li a series of calculations is made for various displacements, one can obtain a curve of the dependence of the initial metacentric height on the draught of the vessel T (see Fig.Sa). In as much as each draughtof'a hydrofoil vessel T corresponds withapyen speed v (see Fig.5~)the curve in Fig.5a may be reconstructed to show the dependence of ho on the speed (see Fig.5b). 'he dependence ho = f(v) far many hydrofoil vessels may be evaluated by experiment1 Comparison of what is found hy such experiment with what is arrived at by calculation will confirm the reliability of the formulae given.

-- I -- 1 Figure 5. Graphs for the determination of the dependence of Figlire 4. Variety of types of shallow-submerged foils the metacentric height on the speed

Adapted translation from Russian of an article in "Sudostroyeniye", No 3, 1964 Stability of the Terraplane on the Ground

Societe Bertin et Cie France

The following is an annexure to Monsieur Bertin's paper presented to the Research Symposium on Air Cushion Craft held in the Department of Engineering, University College of Swansea, from July 21st to July 23rd, 1964, and published in "Hovering Craft and Hydrofoil" in the July 1964 issue

Characteristic of a cmpressor: or: = witl, p = relative pressure 0 volume flow hence:

dl' = ffQdQ With (2): Iffpis < 0) In the plenm chamber exit, the jet velocity Vj is given by: I p, = -pv? . pc = chamber pressure p = jet fluid density Putting: Volume flow:

where :S- = iiDh.

we have: with : D = cushion diameter h = cusl~ionIleight.

From (3), neglecting the variation of p and volume of air in the plenum chamber is the stiffness coefficient; the lift of the cushion is: dQ = Sj dVj + V. dS. J J (4) L = Spc With (1): where S is the basic area of the cushion. Hence:

d = Sdpc if p = p, as stated before and (2): d dv. =P (4b) Multiplying the first member of equation (8) by S, andwith Sj = kh, fVj hence dS. = k dh , we have: the equation (4) becmes:

Neglecting the pressure loss we have: Let a small incidence: dB with respect to the equilibrum position, 4 in hidimensional, the variation of average ti corresponding to dB is: \

I 7his relation is also true for circular cushions.

b1 : rolling (or pitching) moment:

dh dM = 2adL = 2aLG- h

With (101, and weight W lifted by the 2 cushions : W = 2 L a dk12 = aWGee = GW-d6 (11) h h

Gravity moment: dhll = W 1 sin dB WldB (if dB is small sin dB* dB) (12)

Total moment (pressure center) :

dhl Stability condition : < 0 , or : d E

CK is < 0 [see (la) and (211: ,hence we wite preferably:

6,. i.nv-, from (13): Numerical values for the Terraplane -

CK is near - 1 (it varies very little with compressor) We have : 1 = 2m - a = 0,75m - h = 0.05 m 1 hence : - = 2,7 et CK a%- 15 a h

hence: CM = (-15 +2,7)8 = -12,38

7he span is b = 4 a, hence is equivalent to a 6% shift of the C.P. per degree:

In pitching, this value is 0,12 (per cent of the length).

lhese values are very large, canpared with those of peripherical jet MI.

Obviously, this analysis is based on simplified assumptions, and is valuable only for the dimensions of the Terraplane. lhe experiments have entirely confirmed this conclusion.

3. DYNAMIC STABILITY

Dynamic beheaviour was studied theoretically and experimeitally.

Wnamic stability is excellent. It decreases when h decreases, (tendency opposite of the one corresponding to the static stability ), but it depends on other factors ufiich are at our convenience. Commercial Breakthrough

Westland has secured the first commercial orders to be placed anywhere for high-speed, amphibious hovercraft. First commercial sale of the 7-ton SR.N5-the world's first production- line hovercraft-was to Bell Aerosystems Company of Buffalo, N.Y. Orders have also been received from Scandinavian Hovercraft Promotion Limited A/S of Oslo, Autair Helicopter Services Limited of Montreal and Mitsubishi Heavy Industries Ltd., of Tokyo. "Off-the-shelf" delivery was assured by the Company's decision, in August 1963, to lay down a production line without waiting for orders. Earlier this year, it was announced that the Ministry of Defence had decided, subject to contract negotiations, to order two of thesevery versatile small hovercraft for military evaluation. In making the announcement, the Minister of Aviation stressed that Westland had carried out the design and development of SR.N5 as a private venture. The Government were coming in after 'private initiative has shown the value of the project.' Only days before, the Company had delivered the 37;-ton SR.N3-currently the world's largest hovercraft-to the British Armed Services, completing the only order so far placed for so large a craft. Backing up these successes, sales negotiations are already well advanced with other possible customers in several parts of the world.

Twin sales successes. A 7-ton SR.N5 (foregroond) keeps high-speed --cornplny wilh the 37f-lon SR.N3 in lhe Solenl

HOVERCRAFT LEADERSHIP

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