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Aviation History
1955
1955 - 1120.PDF
232 FLIGHT, 12 August 1955 The fine lines of the Britannia, 100, shown here, are enhanced by the increase in fuselage length introduced in the Series 250 and 300. Apart from the in- creased length, later Britannias will otherwise be superficially similar. Bristol Britannia . . . part of the fin-tip is the Loran receiver and it is proposed thatthe H.F. aerials should be suppressed in each wing-root leading- edge. Twin A.D.F. suppressed loops are submerged in the fuse-lage upper skin and the search radar is contained beneath a radome in the unpressurized portion of the nose. The latter partof the aircraft also carries V.O.R./D.M.E. homing aerials on either side and a D.M.E. distance aerial below. Furnishing. A greater variety of interior arrangements ispossible with the Britannia than with any other airliner. Basic seating at present envisaged is as follows: Britannia 100 = 90;300=99; 300 L.R. = 93 + crew rest; and 250 L.R. = 84 ( + 2 in lieu of pantry + 13 in lieu of above-floor cargo). Correspondingcargo capacity is: 100 = 714 cu ft; 300/300 LJt. = 910; and 250 L.R. = 1,669. All long-fuselage Britannias have two pres-surized under-floor holds of 386 and 443 cu ft capacity, with doors 30m x 51 in. All furnishing is non-structural. In the 250 L.R. a bulkheadcan be inserted at any desired position to separate the passenger compartments from cargo stowage forward, the latter compart-ment having a freight door 73in x 93in incorporating a normal passenger door within its frame. Freight is normally restrainedby nets, but the 1.25g landing case can be taken by a ply-faced bulkhead, and full crash loads can be accepted by the metal-facedbulkhead ahead of the container in the crew bay. Any form of passenger seating is possible, including arrangements for 4-, 5-,and 6-abreast. Typical arrangements are shown in the accom- panying artists' impressions (p. 224). The L.R. Britannia can beequipped with approximately 17 bunks as standard equipment. Distribution of electrical power in later Britannias can be shown diagrammatically in the form below. Full load can be maintained on three alternators; the latter can be driven by windmilling airscrews. 50 kVA GENERATOR 208 cjnd 104 V A.C. (DUAL WINDINGS) Airscrew and spinner de-icing Tail unit de-icing Windscreen heat Main hydraulic pumps 112 V D.C Pantry ovens, etc. Water heating Engine starting Feathering motors Flap motors Emgcy. hydraulic pump Fuel pumps Cabin lights Powerplant de-icing Elevator horn de-icing Air intake de-icing 115 V A.C. 400 c.p.s. 28V D.C. General services Pitot-head heaters Windscreen wipers Cabin and cargo hold lights External lights Radio Emergency throttles Throttle controls Fuel gauges Engine and flight instruments Auto, cabin temperature control Autopilot Airscrews Flight systems Engine instruments (26 V A.C.) Search radar Loran 1,600 c.p.s. Development. An outline of structural testing has alreadybeen given. Flight testing is being conducted equally rigorously and there is no question that the Britannia 100 is today at a higherstate of development than any other new transport has been prior to entry into service. Last year a programme of intensiveflying was announced involving a total of some 2,000 hr, 1,000 of which were to be on one airframe, before the grant of a C. of A. This programme has now been completed highly successfully,and it is clear that the behaviour of the aircraft is quite out- standing. The first prototype, G-ALBO, has now logged about1,100 hr; this machine belongs to the Ministry of Supply and will be used to develop the Proteus 755 at the end of the year.The first production machine, G-ANBA, has already completed full tropical and elevated-airfield trials and has flown 650 hr.The second production machine, ANBB, is in the process of com- pleting some 280 hr furnishing and handling trials and ANBC,the latest to fly, is scheduled to undertake route-proving. The latter task will involve some 250 hr for a C. of A., and itis scheduled to start at the end of the month. Operationally BC is a completely representative aircraft, with all 90 seats, bar,pantry and toilets. Four B.O.A.C. crews are assigned to the programme (two per trip), all flight observers, maintenance andinspection personnel being Bristol employees. The schedule cifies three flights to Johannesburg, two to Tripoli, two to Tel Aviv and two to Bombay/Karachi. To Tripoli 97 personswill be taken; otherwise 54 will be on board on each flight, together with a considerable quantity of spares and other equip-ment. An unrestricted C. of A. is expected to be granted as soon as route-proving is completed. What might be termed "airline" behaviour of the Britannia 100has so far been tremendously promising. At present, an operating Check 1 is given at 50 hr, Check 2 at 150 and Check 3 at 300;Check 4s are expected at 1,200 hr although ALBO was given one at 750. Maintenance man-hr per check have been verylow. Check 1 on ALBO—including the inevitable "instrument snags"—has never taken longer than from midnight to 7 a.m.with less than 12 men on the job; Check 2 on ANBA was carried out during three successive nights from midnight to 8 a.m. withthe aircraft flying each day; and Check 4 on ALBO required four days. It has been established that normal airline proceduresare applicable. Engine overhaul life is now on the basis of 300 hr for theProteus 705, developed engines going up to 450. These times reflect much longer periods successfully run during development.Airscrew time is on a 600-hr basis and a significant improvement is expected to follow the introduction of nickel-plated blades.All accessory systems have shown outstandingly high service- ability which, in view of their complexity, reflects excellentengineering and a high level of development. The last few paragraphs may smack of "sales talk," but they doindicate that this largest of all post-war transports really does work. There is scarcely a major airline in the world which hasnot studied the Britannia in detail and it is a sine qua non that their studies have shown it to be, on paper, the most capableand economical transport ever designed. Nevertheless, orders for equipment of this calibre are rarely placed until the operatoris assured that he will not be let down. Indications are coming ever more strongly that Bristol's Britannia will not let its pur-chasers down, but will more than live up to its already great reputation. In doing so, it cannot fail to put air transport on anew level of economy, reliability and comfort.
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