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Aviation History
1959
1959 - 1201.PDF
586 AIR COMMERCE . /; FLIGHT UP-TO-DATE WITH THE CARAVELLE J Weight and Power Increases in Prospect HERE is a report from Mark Lambert of "Flight's" staff about the. latest design progress with the Sud Aviation Caravelle, due to enter - service in three weeks' time with Air France and S.A.S. DURING a recent tour of the French aircraft industry inFlight's Gemini, I landed at Toulouse Blagnac and waslucky to catch M. Satre, Sud's chief engineer and chief designer, who was responsible for the original Caravelle conceptand its pioneering engine installation. I asked him right away whether, in the light of events since 1955 (when Flight publisheda full description of the Caravelle) he had in any way changed his faith in rear-mounted engines and the twin-engined concept. Hisreply was typical. All single-engined jet fighters had, effectively, rear-mounted engines—and "even the ancient Chinese rocketsused such an installation." Neither was his faith in a twin-engined powerplant in any wayshaken. Firstly, he said, two good engines were better than four mediocre ones and the DC-3 had amply proven the reliability ofan aircraft with two first-class engines. Secondly, real safety in multi-engined aircraft depended essentially on the engines beingcompletely separate; and he cited the case of a Pan American Boeing 707 which had lost two engines together at 1,000ft overParis because of a difficulty which arose when water injection and de-icing were used at the same time. In the case of propellerengines, an engine failure not only caused a loss of power but a loss of slipstream-generated lift over one part of the wing withthe result that the yawing moment was accompanied by a rolling moment after failure. The Caravelle's engines were, he continued, slightly offset sothat their thrust line passed through both the longitudinal and the vertical e.g. position. They were mounted high on the rearfuselage in order to avoid ingestion of foreign material either when the wing became iced or when the undercarriage might be throw-ing up stones when the tail was right down just before take-off. This last factor had worried Sud during the early days, but theyhad in fact experienced no difficulty. Nevertheless, the intakes of the two Avons had been turned slightly upwards and inwards inproduction aircraft. About the independence of individual engines in multi-engineinstallations, M. Satre said that if carburettor icing were dan- gerous, then the proper solution was not to have four carburettorsand four engines but to overcome carburettor icing. Similarly, any fuel system failure should not be able to affect more than oneengine at a time. More specifically, about the Caravelle, he said that even if he had wanted to install four engines there was not anengine of 7-8,000 lb thrust which was as well tried or reliable as the Rolls-Royce Avon now being used. RB.141 Installation I next asked M. Satre about Caravelle developments and he toldme about the stages at present planned which would finally lead to the fitting of two Rolls-Royce RB.141s, giving 14,000 1b thrusteach, which would give the Caravelle a 50 tonne (110,000 1b plus) gross weight, raise its cruising speed to 860 km/hr (465 kt) anddouble its present range to 3,000 kilometres (say 1,600 n.m.). In order to provide a freight version for either military or civil use,he replied that a swing tail, a la Convair 880 or CL-44G, was possible, but that the first Caravelle prototype had already hada large freight door in the port side just aft of the flight deck, and that orders for such a Caravelle freighter could be taken. The present standard Caravelle is powered by two Rolls-RoyceRA.29/ls giving 10,500 1b thrust each. It has a cruising speed of 405 kt. From the 36th production machine onwards the RA.29/3will be fitted, raising the power of each engine to 11,400 lb and the cruising speed to 430 kt. The gross weight will also increasefrom 43.5 tonnes to 45 tonnes (96,000 1b to 99,500 lb). Later still the RA.29/6, giving 12,200 lb, will be fitted and the gross weightand cruising speed raised respectively to 47 tonnes (104,000 lb) and 445 kt. The change from RA.29/1 to RA.29/3 simply involvesthe use of a different turbine blade material; this can be incor- porated as a retrospective modification in the first 35 Caravelles.The RA.29/6 has an extra compressor stage which provides improved s.f.c. as well as higher thrust—but it will be possible inthe future to convert RA.29/3s to /6s retrospectively. Only slight airframe changes are required to accommodate these more power-ful Avons. The final stage at present envisaged is the incorporation of twoRolls-Royce RB.141s in a 50 tonne (110,000 1b) Caravelle. Thrust will be slightly more than 14,000 lb per engine, with an s.f.c.10 per cent lower than that of the RA.29/6. Static strength tests of the present Caravcllc airframe have proved it capable of the Source of the Caravelle news on this page is M. Pierre Satre (left), chief designer at Sud, and tcreator of the Caravelle. On the right is Pierre Nadot, chief test pilot gross weight envisaged and of the 465 kt cruising speed which wilithen be possible. The range available will then make the Caravelle capable of flying all the American domestic routes except thenon-stop coast-to-coast. Incidentally, the RA.29/3 will have a noise suppressor, while the RB.141, with its by-pass arrangement,will probably not require one. Sud consider that the RB.14l] which can be delivered as a complete engine ready for installation,'is considerably more advanced than the American turbofan units. The Production Outlook After speaking to M. Satre, I was shown something of Caravelleproduction which is now arranged on a three-shift basis, seven days a week with the object of producing 25 machines by the endof this year. The four Sud factories in Toulouse alone are keeping 6,700 workers busy and an impressive shoal of aircraft is alreadyto be seen in the new assembly hall. Some 315 sub-contractors are involved, including 18 British and 18 American. The cylindricalsection of the fuselage is made in Toulouse and the wings at Sud's factories at St. Nazaire and Nantes. The tapering section of thenose is made by Sud at Marignane and the tapered tail section by Latecoere at Toulouse. Fixed horizontal and vertical tail surfacesand the engine nacelles are made by Fiat in Turin because of their experience in spot welding; and elevators and rudder are beingmade by the Forges de la Boissiere near Toulouse. The under- carriage comes from Hispano and the powered controls fromSAMM. The assembly and equipment of each aircraft takes 360,000 man-hours. Particularly impressive is the fact that Sud have realized theimportance of after-sales service and have organized not only a very large office to provide such service for all the company'sproducts but also a special department of 250 people to deal solely with the Caravelle. The whole department is headed by M.Chabert at Paris and the Caravelle department at Toulouse by M. Colas. Sud have based their operations in this respect on thoseof the two companies whom they consider to be the most experi- enced in the world, namely Douglas and Rolls-Royce. In addition,they have been able indirectly to draw on the experience of Vickers with the Viscount. A very considerable stock of spareparts ready for immediate delivery has already been set up with 8,000 airframe parts and 1,000 systems parts; and a second stockof major sub-assemblies for crash repairs, including complete undercarriages and wings, is now being assembled. A tremendous enthusiasm seems to have seized all Sud personnelin touch with the Caravelle project. Not a single strike or work stoppage has occurred and the number of Caravelles on finalassembly is itself evidence of the capacity of Sud, and indeed of the whole French industry, to produce an effective transport air-craft. There is a real determination to provide what the Americans would term a complete transport system and not just an airframewith which the customer is left to make his own way. The Carayelle is, in fact, rapidly joining the Nord Noratlas, FougaMagister, Sud Alouette and the Dassault fighters in the front rank of French aviation exports. If work on the Caravelle were to stop,it is said that 50 per cent of the French aircraft industry would be left idle. The first Caravelle, being used at Toulouse for S.A.S. crew-training, made some spectacular short take-offs during my visit. CONVAIR TEST PROGRAMME /~*ONVAIR still expect to have F.A.A. certification of the 880^ completed by May 1, 1960—the schedule publicly announced two years ago. Three aircraft are now being used for flight tests,and the structural and engineering test programme is under way. The first aircraft to fly has, since January 27, been instrumentedand used for basic performance and systems tests. The second airframe is being used for static testing and the third aircraft offthe line is being used for the same work as the first. The fourth will be fully furnished and trimmed and used for acoustical,pressurization and air conditioning tests. The first aircraft will be modified and re-instrumented as neces-sary (thrust reversers, for example, will be fitted in June) and the third used for taxi-testing and for finding the optimum setting forthe thrust reversers.
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