FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1958
1958 - 0410.PDF
COMET RESURGENT . . . 4 will be certificated for 156,000 lb. But the measurements andassessment of the Comet 3 inspire confidence in the behaviour of the Comet 4 beyond those limitations. It will, D.H. hope, be astraightforward matter of checking—a rather elaborate production flight test. The actual Comet 4 programme will, according to present plans,be as follows. First—probably as these words are being read—the aircraft will undergo an extensive series of ground-functioningtests. All the systems, notwithstanding the hundreds of hours of rig-tests which have gone into their making, will be thoroughlychecked according to a pre-arranged programme, especially those which could not be made fully representative in the Comet 3. Forexample, the flying control system, undercarriage, flaps and so on ' will undergo a large number of reversals, the electrical system willbe subjected to a series of full-load checks, and the cabin air system will be run under simulated flight conditions. Next will followfuel-flow calibrations and engine-runs, after which the first flight will be made. The Air Registration Board require a minimum of 250 hoursbefore full Comet 4 normal-category certification, of which at least 100 shall be under operational route-proving conditions. D.H.may be able to clear the aircraft in less flying time than 150 hours; but—as the next article relates—the balance up to 250 hours willbe accomplished by B.O.A.C. No doubt the first few flights will be concerned with an assessment of the new systems—particularlythe flying controls, which are mechanically quite different (mainly in respect of the emergency arrangements and the trimming) fromany previous Comet, including the modified Comet 3. There will follow an assessment of performance and handling,which will take the form of checks on Comet 3 results, plus items which could not be covered with that aeroplane because of itslower gross weight. For instance, high Mach number buffet- boundary will be explored, rough-air speeds will be checked, andhandling at all c.g.s will be assessed throughout the speed range 426 FLIGHT, 28 March 1958 "Had the Comet 3 never been built, D.H. would have been confronted with perhaps a two-year programme of Comet 4 flying . . ." The Comet 3 is seen on test from its Hatfield base. "Flight" photograph from the stall (including the ground stall at the higher weights)up to the limiting Mach number and i.a.s. In general, all the more critical handling characteristics found on the Comet 3—which the A.R.B. will have flown for 14 hours in its modified form—will be checked on the 4. The performance evaluation will comprise spot-checks ofComet 3 results (e.g., a few cruise-consumption checks on the 40-odd done on G-ANLO) and of course there will be new per-formance measurements beyond the weight limit of that aeroplane up to the new maximum take-off weight of 156,000 lb. This willrequire further tropical trials in Africa, where the Comet 4 will probably also make a search for dry ice in the inter-tropical front.There is no anxiety that the RA.29 will be susceptible to these conditions, as was the reverse-flow Proteus; but its dry-icebehaviour will be checked nevertheless. It should be recorded here that the Comet 4's take-off perform-ance, which because of the aeroplane's plentiful power has always been good, looks like being well up on estimates, judgingfrom Comet 3 results. And, as recently recorded in Flight, the basic weight of the first production aircraft has turned out to beconsiderably less than the brochure. In other words, range (or payload) is likely to be better than estimated. In general, performance tests on the Comet 4 will amount toabout 20 per cent of those done on the Comet 3. That aircraft will still be fully employed, not only for reverse-thrust landingtests, but also for such things as autopilot approach-coupler checks, of which at least 50 now have to be made before certification canbe granted. And quite soon, no doubt, the Comet 3 will have its wing span clipped for an assessment to be made of Comet 4Bperformance. It is difficult to estimate the amount of time which the A.R.B.will require for their flight evaluation of the Comet 4 before full certification is granted. But the D.H. flight-test departmentfeel confident that it could be less than 10 hours—an encouraging indication of the amount of development which has gone into dienew Comet, and the extent to which it will be taken as read. B.O.A.C. AND THE COMET 4 MANY times during 1954, after the Comet 1 had been with-drawn from service, did one hear the question—particu-larly from B.O.A.C. crews: "When do you think the Comet will come back?" There never seemed to be any doubtsthat it would come back, so indestructible a symbol had the Comet become. Though stunned by the way the Comet had suddenly fallen outof their lives, B.O.A.C.—literally everyone in the Corporation— did not lose faith in the aircraft. The Comet had inspiredB.O.A.C.'s esprit and emotions as no other aeroplane had pre- viously done. It was popular with crews, it swept in the traffic, itput B.O.A.C.'s name in front. The air-transport industry has grown up a little since thosedays, and airlines are (to quote Mr. Donald Douglas) more interested in making money than headlines. The Corporation'snew fleet of 19 Comet 4s should make both. B.O.A.C.'s Comets will come back, in their new form, nextSeptember—nearly seven years after delivery of the first Comet 1, and more than four years after its withdrawal from service. Asrelated in the preceding pages, the Corporation's new Comets will be virtually new aeroplanes, having twice the power, twice therange, a completely new structure and much improved systems. According to present plans, B.O.A.C. will introduce the Comet 4into service five months after taking delivery of the first aircraft in September. February 1, 1959, is the target-date scheduled for theinauguration of services to Australia. Comets are being put onto the Kangaroo service first in view of the partnership with Qantas;the Australian airline is due to take delivery of its Boeing 707-120s (bought largely with B.O.A.C.'s Comet 4 competition in mind) inMay 1959. How quickly Qantas will establish their 707-120s in service after delivery remains to be seen; but Comets shoulddominate the Kangaroo route for at least four months. Comet 4s will be introduced at a four-times-weekly frequency, following the Capt. T. B. Stoney, manager of B.O.A.C/S Comet Flight. traditional Britannia 102(formerly L.749A) route of London, Zurich, Beirut,Karachi, Calcutta, Singa- pore, Djakarta, Darwin, andSydney. One of the four services per week will berouted via Colombo (Katan- ayaka), a service which isdue to be inaugurated by Britannia 102s next month. Britannia 102s will becompletely and immediately displaced from the Australian route by Comet 4s, which will subsequently—starting in June 1959—displace B.O.A.C.'s medium-range turboprop from the Corpora- tion's London-Tokyo route. By September 1959 Comet 4s shouldbe handling most of the Far East services. Next, in January 1960, the Comet will take over the South African Springbok route, andby then the Britannia 102s will be relegated to the Corporation's services to East and West Africa, and those terminating inPakistan and the Persian Gulf. There is a possibility—though B.O.A.C. do not confirm this yet—that Comets will reopen theCorporation's services to South America via the South Atlantic (suspended when Comet 1 capacity was withdrawn in 1954) inApril 1960. There have already been suggestions, as a result of PanAm'savowed aim to open transatlantic Boeing 707 jet services in October of this year, that B.O.A.C. should simultaneously introduce Comet4s into transatlantic service. B.O.A.C. decline to be pressed on
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
