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Aviation History
1951
1951 - 1160.PDF
•"•*«* 721 FLIGHT, 15 June 1951 The Hermes V draws up '^alongside the attractively designed terminal building at the "long-distance" Paris airport (Le6gi/rg£LJi_con- cerned moirTfywith European* traffic)f "Flight" photographsV FRANCE SEES the HERMES V A 46-minute Trip from London to Paris for Demonstrations to Continental Operators THE Continent had its first view of a Hermes V on Tuesday,June 5th, when the Handley Page four-turboprop airlinerwas flown from London Airport to Orly for demonstration to French operators. Though having an interior that will, if desired, accommodate 74 passenger seats, G-ALEV (the second prototype, which made this particular trip) is furnished in the luxury style of its piston- engined counterparts3 the B.O.A.C. Hermes IVs, with "rechnable" chairs and virtually unbounded leg-room. At the moment the big question-mark in Hermes V planning concerns the power plant. The 2,820 h.p. Theseus is, of course, installed at present; a new mark of Proteus, with considerably increased performance, is a possibility for production aircraft. In view of Bristol commitments with the Olympus, however, and the fact that a flow of Proteus will be required for their own Type 175 airliner, a problem clearly exists. However, we are concerned here with the existing Theseus version and its trip to Orly, in which we were invited to participate. Eighteen people were on board, including, among the H.P. repre- sentatives, Mr. H. Brittlebank (technical sales), W/C. J. D. H. Slade, recently appointed liaison officer between the firm and its customers, and Mr. S. A. H. Scuffham, public relations. There was a flight crew of three, under H.P. test pilot "Duggie" Broomfield. The 0816 hr take-off from London Airport was in warm, cloudless conditions, with a beam wind of little account at any altitude. Flying at 81,000 lb a.u.w. (permissible weight of G-ALEV, on a special-category C. of A, is 84,0001b), Broomfield made a frankly "demonstration" take-off, then settled to a climb that took us up to 10,000 ft in 6J- min. Thereafter the aircraft cruised at 235 kt I.A.S., with compressor revs at 7,800 and turbines at 8,150 (the Theseus has a "free" turbine, of which more anon). The English coast was crossed at Beachy Head 15 min after take-off, and the French coast, at Dieppe, 13 min later. About 50 miles from Paris the let-down was started, at 6oo-7ooft/min and 285 kt I.A.S.; and 46 min from take-off we were in the Orly circuit, the time representing a ground speed of almost exactly 300 m.p.h. The airport control thereupon spoiled Even without an airline's colours the Hermes V looks impressive. Final approach to Orly : for take-off, the new double-slotted flaps permit a 2,000 Ib a.u.w. increase; the landing run is reduced by 9 per cent. the effect by standing the aircraft off for the inordinately longperiod of 12 min, although very little other traffic appeared to be moving. Even so, the existing turboprop airliner "record" (theViscount's 59 min) was just beaten; there can be no accurate comparison, however, for the Viscount flew from Northolt toLe Bourget (190 n.m.); L.A.P. to Orly is 198 n.m. As to smoothness, the Hermes V was a little disappointing, but the vibration that was apparent was quite clearly a matter of engine synchronization. In the "free turbine" there is no mechanical connection between the turbine driving the airscrew and the turbine driving the compressor. Because of this fact, and since no two engines are identical in the rate at which they warm up and settle to their work, synchronization is tricky until that period has been passed; after this, we were assured, near-perfect synchroniza- tion can be obtained, and the periodic vibration vanishes. The Paris trip was too brief for a fair test. This same question of free turbines is interesting in relation to approach technique. On the Hermes V the method is to cut the two outer engines to ground idling speed and come in at 7,800 compressor r.p.m. (i.e., max cruise) on the two inners, a rate of descent of about 200ft/min being held and height adjusted by small movements of the power levers. If it should be necessary to go round again, the flight engineer opens up the two outers, which will produce full power after 3-4 sec. It was possible to talk in comfort, without raising the voice, at any point along the cabin, and the high-frequency engine-scream (or perhaps "whistle" is a better description), so audible outside the aircraft, is effectively damped by the cabin soundproofing. It seemed no more obtrusive than the normal sound of airflow over any moderately clean fuselage.. On arrival at Orly the crew began a strenuous demonstration schedule, taking on board full loads of officials, airline executives and pilots, and giving them an hour or more aloft, several of the pilots being afforded an opportunity to fly "EV" for themselves. One of the companies whose executives seemed to be taking an unusually close interest was T.A.I. (Transports Aeriens Inter- continentaux). With a fleet of seven DC-4S, heavily utilized, they fly from Paris to Casablanca, Brazzaville, Abidjan, Madagascar and other places in and around Africa. Several of the stages are of a length that would be economic for the Hermes V.
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