FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1955
1955 - 1244.PDF
358 FLIGHT, 2 September 1955 THE DE HAVILLAND AIRCRAFT CO., LTD. Hatfield, Herts. Telephone: Hatfield 2345 Comet The Comet 3 to be demonstrated at Famborough is regarded as the development prototype of the new Comet 4. It is at present undergoing an intensive flight-testing pro- gramme to ensure that a considerable pan of the corresponding programme for the Comet 4 will be completed before that aircraft actually takes the air. The Comet 3 already has behind it some 150 hr of flying, in the course of which the performance has been measured, and from this the basic capabilities of the Series 4 have been estimated. The makers state that with due allowance for take-off, climb, diversion, stand-off, descent, etc., the stage length of the nev» aircraft is expected to be more than 2,900 statute miles, carrying the volumetric first-class pay- load of 16,400 lb. Corresponding figures for the tourist version are 2,700 statute miles and 19,300 lb. This capability, it is claimed, establishes the Comet 4 as a machine capable of operating non-stop the majority of the world's busiest trunk routes. As outlined in a statement earlier this year, the Comet programme entails the building of twenty machines for B.O.A.C. These will be powered by Rolls-Royce Avon R.A.29 engines, of 10,500 lb static thrust, whereas the Mk 3 has Avon RA.26s, of 10,000 lb thrust. All-up weight will be 152,500 lb against 150,000 lb, and fuel capacity 8,760 Imperial gallons—an increase of 400 gallons over the Comet 3. Cruising altitude will be the same for both versions, namely, 42,000-45,O0Oft, but cabin pressure differential for the Comet 4 will be slightly higher at 8.75 lb/sq in. With their Comet fleet B.O.A.C. will be able to fly to Johannesburg with stops at Cairo and Nairobi. There will be direct services from London eastwards to Beirut, thence to Karachi, Bangkok, Okinawa and Tokyo. A de Havilland announcement runs, "On the North Atlantic route the Comet 4 will carry its full capacity payload from London to Gander, Newfoundland, with full reserves, thus making its applica- tion to the London-New York service an economic possibility." Structurally the aircraft will incorporate all developments accumulated since the first flight of the Comet 1 in 1949, includ- ing those resulting from experience gained in some 30,000 hr of airline operation. Super- imposed on this experience was the investigation of 1954—an undertaking, the makers point out, without precedent in aeronautical engineering. Advantage is being taken of advances in the knowledge of metal fatigue, and it was announced in May that in the preceding months a great deal of repeated-load testing had been undertaken on full-scale components. Especially, the stress level in the fuselage seam joints and cut-outs has been kept low, so that local damage should not affect the safety of the structure. Concerning the performance of the Comet 4, the makers state: "The take-off performance is such that only very rarely will this be a limiting factor. The take-off performance has been evaluated on the assumption that an engine fails at the critical point, and the aerodrome length required is denned as the distance to reach a height of 50ft on three engines or the total accelerate-stop distance. Because of the increase in thrust of the Comet and in spite of the greater all-up weight, the take-off performance of the Comet 4 will be somewhat better than that of the Comet 3. As a general rule it may be said that the take-off weight of the new Comet may be increased by about 3,500 lb above mat of the Comet 3 for a given aerodrome length. The optimum cruising speed of the Comet 4 corresponds to a Mach number of 0.74, which is equivalent to 489 m.p.h. in standard atmosphere rising to 506 m.p.h. in an atmosphere IS deg C hotter than standard." Data for Comet 4 (Illustrations show Comet 3) Power plant ... Four RoUs • RoyceAvoaRA.2* Span 115ftLength Illlt6in Gross weight 152,500 ibCruising speed ... 489/506 m.p.h. OO
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
