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Aviation History
1955
1955 - 1618.PDF
FLIGHT, 11 November 1955 735 the 2,000 hr mark had been hit, and the bulk of the C. of A.work completed. The one notable exception to the latter was clearance for "A.R.B. heavy ice"—a commodity hard to come bywhen deliberately sought, as every flight-test team is frustrated to find. Ice-hunting flights from Entebbe, in the course of whichG-ANBC was flown into the severest weather that equatorial Africa could offer, resulted only in light icing, although on oneflight the storm warning radar nose—ironically—was damaged by a savage hailstorm. Some icing was unexpectedly experiencedduring a homeward proving-flight from Johannesburg; this was dispelled by the de-icing system after accruing to l^in (require-ment is for a 3in deposit). The Britannia's de-icing system is understood to be the onlyremaining major item to be cleared before A.R.B. certification, and to ensure that at least part of it can be tested to order,G-ANBA is being fitted with a water-spray-rig aft of the wing so that the electrical tailplane system (the wings are hot-air-protected) can be exercised and proved. To date A.R.B. pilots and observers have flown 100 hr withthe Britannia—not a large figure when one considers the magni- tude of the task of achieving certification for an entirely newaircraft as large and complex as this one. Fatigue tests of the structure, the first phase of which—equivalent to a life of 20,000 hr (5,000 reversals)—were satisfac- torily achieved in the R.A.E. water tank at Farnborough (Flightfor July 22nd, 1955). A scatter-factor of, say, six when applied to this figure yields a safe life of more than 3,000 hr. Component-testing has proceeded meanwhile, and the full-scale tank pro- gramme will be continued to keep the tank-tested "life" wellahead of hours flown. It is worth noting that, to provide repre- sentative data for the Britannia's tank tests, strain gauge measure-ments of in-flight loads were made in the course of 150 hr flying by G-ALBO. In common with de Havilland and Vickers, Bristolare building their own test-tank, the main structure of which is now complete. So far as engine development is concerned, no more needbe said about the 3,780 e.h.p. Proteus 705 of the Britannia Mk 100 than that it is ready for public service. The engine was infact cleared for passenger operation last year, and the detailed development work necessary for Britannia certification has beencompleted recently. Like the Rolls-Royce Dart, unspectacular in performance but with a sound background (40,000 hr) of de-sign and development, the Proteus is likely to do a good job for many years to come.The scene in the Filton assembly hall is one of heartening activity. Photographs do not adequately record the mind-batter-ing size of the great Britannia hall, or convey the almost clinical neatness of the assembly pattern. Eight Mk 100s, numbers fiveto twelve, closely follow one another in the race towards com- pletion. Each machine has its target date boldly displayed—e.g.,Britannia No. 11, February 1956—while a detailed chart by each keeps check of the progress of every assembly operation. Thereis now substantial evidence in the nearby fuselage and wing de- partments to account for all 15 of B.O.A.C.'s Mk. 100s. Theaim is to deliver four by the turn of the year, with the others following at close intervals. Of the aircraft completed, G-ANBA (780 hr flown to November3rd) is having its ungainly water-spray apparatus fitted; G-ANBB (278 hr) is at Short's in Belfast for final completion; and G-ANBC(331 hr), looking work-worn after its 250 hr of route trials (during which it averaged 7 hr per day), is on overhaul. Production air-craft No. 4, G-ANBD, is on final inspection and engine-runs before first flight. The prototype, G-ALBO (1,144 hr), has beenset aside for development of the Proteus 755 (4,120 e.h.p.), power- unit of the 250 and 300 Mks of Britannia. Total Britannia hoursto date, including the 51 flown by the second prototype, G-ALRX (dismantled after a forced landing) are thus 2,583. In an adjoining bay of the great assembly hall is the firstBritannia 300—at once distinguished from its Mk 100 neigh- bours by the added 10ft 3in of fuselage. This prototype isbeing built to a Ministry of Supply order; the remaining seven 300s, all for B.O.A.C., will be the responsibility of Shorts, thefirst being due off the Irish line by the end of 1956. The general production programme is distributed between Filton and Belfastas follow:— Filton: 15 Mk 100 (B.O.A.C), one 300 (M. of S.), 19 Mk 300 L.R.(B.O.A.C, El Al, C.P.A.L., etc.). Belfast: 7 Mk. 300 (B.O.A.C.), 8 Mk. 250 L.R. (R.A.F.).Filton will eventually be left clear to concentrate on building 300 L.R.s—the type for which more commercial orders are con-fidently expected "very soon." B.O.A.C. will receive their first 300 L.R. from Filton at the beginning of 1957, just as the lastof their 300s is due to be finished at Belfast; there may, in fact, be an overlap period. El Al (whose detailed contract specification,unlike B.O.A.C.'s, is already settled) will receive the first of their three 300 L.R.s soon after, if not simultaneously, and C.P.A.L.will take delivery before the end of 1957. It is of interest that current delivery-date for new orders is late 1957.And so to the 64-dollar question: when will the Britannia enter service? Precise information on this point is not easilycome by at present—which is understandable, since the answer lies somewhere in the centre of a triangle formed by the A.R.B.,Bristol and B.O.A.C. As recently as September it was stated (Concluded on page 760) BRITANNIA AIDE-MEMOIRE _# JJJJJJJJJJJJJJJJJ MM ^mmm 99 PASSENGERS 84 PASSENGERS 300 LR td JJJJJJJJJJJJJJJJJ 93 PASSENCERS Gross wt. (Ib) 150,000 155,000 170,000 170,000 Powerplant Proteus 705 3,780 e.h.p. Proteus 755 4,120 e.h.p. Proteus 755 •4,120 e.h.p. Proteus 755 4,120 e.h.p. Max. fuel (Imp. gal) 6,670 6,670 8,486 8,486 Mean cruise speed (m.p.h.) 375 406 406 406 Length ft in 114 0 124 4 124 4 124 4 3730 5J70 W40 STILL AIR RANGE St. miles 3.420 iHO 5,710 STILL AIR. RANGE St. miles I6.370- »— A V 4940 4220 7030 STILL AIR RANGE St. miles
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