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Aviation History
1949
1949 - 1460.PDF
224 FLIGHT 25th August, 1949 Twelve thousand feet above the fields of Sussex, the Viscount's pilot draws up to the camera (upper view) and, when close beside, feathers his port turboprops. The airscrews do not stop entirely. VISCOUNT in the air . . of on a cabin table) through which vibration might be expected if any had been present. Not only did the coin remain on edge for some minutes, but I was able to make a turn of just over 30 deg bank before it fell. I did not try stalling, but understand that it is normal and is heralded some 7 m.p.h. in advance by mild buffeting of all control services. (Incidentally, all the controls are metal-covered, the ailerons being in two sections locked together). With the full 57 degrees of flap, and power on, the stall becomes rather abrupt if the aircraft is held into it. However, the speed is then remarkably low and one could scarcely get into the condition unintentionally. The maximum wing-loading of the Viscount is 5p\8 lb/sq ft; of the 700 it will be 49.8 lb/sq ft. The Viscount is remarkably stable and boasts as nice a pair of ailerons as one could wish. They are most respon- sive, particularly at approach speed, even though they become pleasantly light. Centering action is pronounced. If two engines are cut suddenly on one side, a touch of aileron and rudder keeps the aircraft straight without any effort at all. There is considerably less apparent effect than one gets with most fours on throttling back an inboard engine alone. As may be judged from the photographs, Mr Bryce was able to formate confidently on the Valetta at 12,000ft and 140 kt I.A.5. with two Darts feathered on OIK side It is a characteristic of turboprops that, when one closes the single power-control, pitch-change leads and momentarily, till r.p.m drop, an acceleration is felt. The reverse is true also This is not conducive to good forma- tion flying until one gets used to it. A very large number of successful and immediate relights have been made with Darts at altitudes from sea-level to 25,000ft. The solitary failure was caused by a faulty igniter plug Relighting drill consists simply of "blipping" the unfeathering but- ton and then opening the high-pressure fuel cock. An hour passed by very quickly in the Viscount, and the crew at once confirmed my impression that normal fatigue is appreciably reduced by the absence of vibration and noise. I was allowed to "play" as we made for Wisley (which is surely the most attractive of manufacturers' air- fields), and, finding a large gap over Epsom Downs—recog- nized from high up by the race course—I dived the Viscount quite steeply with Darts throttled back from the cruising 12,500 to 10,000 r.p.m. until about 260 kt I.AS. were registered. There was no undue tightening-up of controls, and it required little effort to pull her round at this speed in as tight a turn as an airliner should ever be expected to make. Cruising r.p.m. are a matter of choice or decision by the operator, up to 13,750 r.p.m. being permitted for continuous operation of the Darts. Maximum for 5 min running is 14,500 r.p.m. Back on Wisley circuit, F/L. Bryce took a little time to induce the knots to fall off, but showed me that the flaps have been specially stressed up to 15 deg angle for use at any air speed to aid in this matter. There is no trim change of note when wheels and flaps are lowered, and the aircraft approaches comfortably and with lively controls at 110-120 kt. Over the hedge less is acceptable at normal landing weight. Although we approached steeply, the round-out gave no trouble at all, and to quote Mr. Bryce, the aircraft " sits down like an old lady". This familiar piece of pilot jargon may, in this instance, be taken to mean that the Viscount sinks gently on to its main wheels, slightly tail-down, for touch down, and then, rocking forward on to the third wheel, stays put. The powerful brakes will pull her up very rapidly if need be. The Vickers Viscount is now one of several British gas- turbine-powered airliners, and it has interesting relatives for research in the Nene-Viking, and in the Tay-Viscount at present under construction. It has already set such a high standard that once introduced into service and sampled by the travelling public it cannot fail to attract passengers from the existing* types of aircraft which it outmodes in such a pronounced manner. No announcement has been made regarding orders for the Viscount 700, but Lord Douglas, B.E.A. chairman, said recently that his Corporation were considering order- ing them for the London-Belfast service. There is little doubt that an order will be forthcoming in the near future ' if, in fact, it has not already been provisionally placed, and for many reasons it is regrettable that the announce- ment of an order has been delayed for so long. As it is, at least 2$ years must elapse before Viscounts could be built and put into service. Perhaps a delay of this sort would have been inevitable for, good as they have proved to be, Dart turboprops are still very new, both as a class and an individual design for use in passenger transports, and a great deal of experience, development work and research for increased economy and period between over- hauls is still required. It is calculated that the Viscount 700 will give 1.45 a.m.p.g. cruising at mean weight at 25,000ft. The speed would be 327 m.p.h. Increasing numbers of important visitors to Weybridge from the Continent and across the Atlantic are a sure sign that the Viscount's fame has spread and its unique qua- lities are being recognized. With the aid of such aircraft, this country prepares to take the lead in both the design and the production of aircraft for the world's routes. , DATA for th« VISCOUNTS Prototype Viscount 700 Span -., ... 89ft 94ft Length ... ... 74ft 6in 81ft 2in Height... 2*ft9in 26ft 9in . Track 21ft lin 26ft I in Whealbai* 21ft 5in 24ft »in Win«Ar«« 885 sq ft 963 iq ft Maxa.u.w 45,000 1b 48,000 1b Mix Wim I ijnf 50.8 Ib/sq ft 49.8 Ib/tq ft Fu.l Capacity ... I 100 fall l.400.jall
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