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Aviation History
1953
1953 - 0376.PDF
374 FLIGHT, 20 March 1953 (Left) A very orderly station for the radio operator is positioned im mediately behind the second pilot's seat. (Right) A pilot can settle into the cockpit comfort ably, and will find the con trols well placed and the view good. VISCOUNT IN THE AIR The latter, positioned by the captain's left elbow, did not seem to be very easy to read or operate in the air—but perhaps this was a temporary installation. A few words about speeds, limitations and actual instrument readings may be of interest. For example, when cruising at 250 kt I.A.S. at 4,000ft we were near the permitted limit for flight below 15,000ft. At 35,000ft this limit is 210 kt. To obtain 240- 2jo kt we used cruising r.p.m. of 13,000 (B.E.A. will use 13,300 in service and at altitude). Under these conditions the J.P.T.s read about 490 deg C, and the torquemeters about 220 lb/sq in. Economical climbing speed is 150 kt at 13,300 r.p.m., but we used 14,000 initially at 180 kt and J.P.T. of 500 deg C. Maximum continuous power is obtained at 13,800 r.p.m. During the return to Wisley some flap tests were carried out, and I was able to feel the controls down to 110 kt. They all remained fully responsive, and I was surprised how little trim-change occurred when flaps were raised or lowered. Neither power nor flap changes result in quick speed alterations. There are five gated positions : 20, 32, 40 and 47 deg (43, 68, 85 and 100 per cent). At maximum a.u.w. of 50,000 lb the minimum control speed with flaps up is quoted as 106 kt I.A.S. With flaps at maximum lift position (85 per cent) the stalling speed at 50,000 lb weight is 80 kt I.A.S. While operating the flaps I also tried the elevator trimmer; it proved to be sensitive and powerful. At dusk I handed over to test pilot Allen (late of B.E.A.) on the Wisley circuit, watched him lower the wheels and heard the rum bling and buffeting this produces in the unpressurized areas under foot. The flaps were lowered by degrees as the approach speed of no kt was assumed, and at the last minute with engines cut right back and speed at about 100 kt he checked drift (caused by the 15 kt cross-wind), lowered the last few degrees of flap and flew gently on. At once the airscrews went to ground-fine-pitch and the braking effect was most pronounced. Maxaret brakes are already fitted to the Canadian machine and will probably become standard, but for normal operations they will seldom be necessary. On this occasion we had no cause to use brakes at all, and were able to turn off the runway at about the half-way mark. I drove away from Wisley feeling that the Viscount has more than a little bit that the others haven't got. And it will not be only the quiet, comfortable cockpit and good view which will please the pilots who fly these aircraft on regular services. AIDS AND INSTRUMENTS A LTHOUGH the Viscount is a smaller aircraft than either *\ the Comet or the Britannia, the radio and instrument *- J^- equipment which it must carry needs to be equally com prehensive. Arrangement of the various controls and dials in a neat and thoroughly practical manner has therefore been of paramount importance—and the success which has been achieved in this direction can be judged from the diagram which appears overleaf. Certain items of equipment, of particular interest, are described below. Radio and Radar.—When the Viscounts enter service this month, B.E.A. propose to operate them with a flight crew of three—two pilots, and a radio operator sitting behind the first officer and facing rearwards. All the radio equipment is housed in two crates; one, containing the remote equipment, on the port side by the front entrance door, the other at the radio operator's station. The complete equipment provided is as follows: Under the control of the pilots—two V.H.F./R.T. transmitter/receivers (Standard Telephones STR.12C); R.T. operation of the H.F. transmitter/receiver (STR.18); Instrument landing System (Standard Telephones SR.14A/15A); Decca Navigator; Zero Reader (Sperry Z.L.i). Under the control of the radio operator— W.T. operation of the STR.18. Under the control of any member of the crew—Two automatic direction finders (Marconi AD 7092 A); intercommunication (Ultra type 17). The voltage regulators are by Murphy. At the present time V.H.F. coverage in northern and western Europe is good, but the farther south and east one goes the less comprehensive it becomes. This fact, coupled with the relatively low range (say 200 miles at 25,000ft) of the system, and its prone- ness to air-to-air interference at great height, make it essential to carry some form of H.F. equipment The backbone of this at the present time is the radio-operator-controlled W.T. installation, and it is likely to remain so for some time. B.E.A., however, are carrying out development work with H.F./R.T., using the same STR.18: eventually, it may be possible to dispense with W.T. operation altogether, and thus reduce the flight crew to two. The I.L.S. installation is quite standard, and is normally used in conjunction with the Zero Reader—though each pilot has, additionally, an I.L.S. cross-point indicator. Visual indication of the three marker beacons is given by a flashing light. For a short-range radio aid, there is at the moment a clear choice between two competing systems—the Decca Navigator and V.O.R. Decca has the advantage that coverage is excellent in the U.K., Germany, Scandinavia and—very shortly—France. V.O.R. stations are extremely scarce as yet. Furthermore, Decca equip ment is in full production, whereas V.O.R. is not immediately available. B.E.A., therefore, are installing the Decca system in their Viscount fleet for a one-year trial; they are also fitting five of the aircraft with the Decca Flight Log. Should the decision be made eventually to fit V.O.R. and not Decca, it seems very likely that D.M.E. would also need to be installed. This is available from Murphy and Marconi, operating on 200 mc/s, and from Ferranti on 1,000 mc/s. (Concluded on page 376, after cockpit diagram on page 375).
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