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Aviation History
1959
1959 - 1856.PDF
FLIGHT, 21 August 1959 41 ARGOSY PROGRESS REPORT A NEW spirit is abroad at Armstrong Whitworth's airfieldsof Baginton and Bitteswell. Three or four years ago, whenA.W.A.'s personnel were faced with no major single chal- lenge, the inspiration that knits a team together and the self-confidence that makes it effective were not always as much in evidence as they so obviously are now. Enthusiasm for theAW.650—A.W.A.'s first civil project for ten years—is running high: clearly apparent is a reaction often observable in the aircraftindustry—an upsurge of drive and energy when a promising new project has to be tackled. The programme has always been kept nearly to schedule, andthe timing is improving. The first aircraft was eight days late when it made its first flight on January 8. The second and third aircraftwere also just behind schedule, the fourth within two days of the programmed date and the fifth on time. The remaining five of thefirst batch of ten will follow at a rate of one a month. By the end of July 350 hr test flying had been completed and of 216 flightsthat had been scheduled only three had to be postponed. There have been no snags at all on the Rolls-Royce Dart 526 powerplants. Each of the five aircraft has been kept to the latest modificationstandard as determined by flight trials. No task has involved more than two days' work and already a third of the instrumented flighttest programme has been completed. By March 1960—A.R.B. and F.A.A. certification date—the flight performance programmeshould be about two months in advance of schedule. By this time, the fourth aircraft (the sales demonstrator) may have done about500 hr general flying, leaving the bulk of the detailed performance- test programme to be completed with the other aircraft. DuringAugust Argosy No. 3 will fly about 30-40 hr on this work during the month and Argosy No. 2 is to leave for Khartoum and Nairobion September 1 for tropical trials lasting about eight weeks and requiring about 200 hr flying. The cold weather programme hasnot yet been decided but will probably be undertaken in Canada. A flight from Bitteswell in the demonstrator—in combinedcargo/23-passenger configuration—showed the aircraft to be steady and spacious, and reasonably quiet even in the cargo hold.This particular take-off was made at 76,000 lb, at which weight 46 sec were required to unstick. In the climb, and again duringpart of the descent, slight lateral shake was experienced in the aft part of the fuselage. This is the residue of an aerodynamic prob-lem that was encountered during flight test and that has been almost entirely overcome by fitting two rows of vortex generatorsaround the decking aft of the cockpit, and a breaker strip (for experimental purposes, a piece of fire hose) around the lower halfof the big, aft fuselage door. A large wing-to-fuselage root fillet has also been tried, and the second aircraft is at present beingmodified in this way. It was found that the pattern of airflow around the aft end ofthe fuselage is extremely sensitive to the positioning of aerial masts or even windscreen wipers. The effect was studied in the windtunnel at Bedford (it could not be reproduced in A.W.A.'s low- pressure tunnel) and the present modifications were then adopted.They may later be revised but no major re-shaping is contemplated. The passenger compartment in the 650, in spite of fore- and aft-facing six-abreast seats (manufactured by Air Transport Seating) is smart and comfortable and the galley is neat. It requires quitea careful inspection to determine where the joint between fuselage and rear door occurs. The windows are small, as befits a freighter(the payload penalty is about 100 lb each) but give quite a good view. On the ground, the Dowty undercarriage leg and the Avery-Hardoll refuelling couplings that are mounted on it are much in evidence. The Hobson/Integral flap motor unit, which winds thedouble-slotted flap smoothly out and down, is noisy, but could if necessary be installed in a soundproof box, a modification for whichhas already been raised. The passenger address system works well, although it faded completely as the engines were started fromthe starter truck. Access to the flight deck is via a ladder from the cargo hold; theimpression gained is that of clambering up from deck to bridge. All Argosies at present have the well-thought-out two^crew lay-out developed in conjunction with the British Air Line Pilots' Association. Equipment includes the Smiths flight system, Deccaand Ekco nose radar. Just how the cockpits of the Riddle Argosies will look is undecided; F.A.A. requirements demand three-crewoperation for aircraft of over 80,000 lb maximum weight, but even if the flight engineer is given the fuel, electrics, cabin air andde-icing systems to handle, his work load is still only five per cent of that of the pilots. The matter has been taken up with the F.A.A. Classic two-crew layout of the Argosy demonstrator. The feathering sequence is a straight run back along the central console and, significantly, the F.A.A. international office in Paris is said tosupport the A.W.A. contention that two crew are ample. Looking over the pilot's shoulders, one passenger made thecomment that an eyebrow window would have given a significant improvement in the view during turns; but apparently thishas not been included (such a window was incorporated in the original design) on the advice of potential customers. Of course,earlier remarks about window weight apply here as well. Another point was that neat and well laid out as the Argosy cockpit is, theoverall finish does not yet quite measure up to recent American practice; it would not, for example, stand comparison with thevery stylish front office of the Electra. Structural testing is now well advanced. Two complete aircraftare being used, one for static and one for fatigue testing. Tails and booms have already been taken to 100 per cent of critical designload (incidentally "without a rivet popping") and the wings—tests on which started later—to 85 per cent. The Argosy's wing isamong the most argued features of the design, so that using a complete aircraft for fatigue testing should help to instil con-fidence in the safe-life of the wing and give experience of the safe-life-and-fail-safe components. About 5,000 hr of fatigue test-ing has been simulated so far and the test cycle, which includes undercarriage, taxying, landing, gust and flap loads, will becontinued until 150,000 hr has been completed. Static tests on the undercarriage are now complete and fatiguetesting should be completed in four months time. This component has been trouble-free and the nosewheel doors, for instance, whichappear to be rather close to the ground, have proved most satisfac- tory. The arrangement has in fact proved advantageous in prevent-ing damage to the propeller blades from debris thrown up by the nosewheel. The big end-loading doors, which obviously presented a trickydesign problem, have worked out very well and almost no snags have been encountered. Deflections are as calculated (an elasticdeformation of up to fin with 500 lb baggage in the doors) and the "pole-vault" device, which lifts the door into position, hasproved very successful. The door locks have been fatigue tested to the equivalent of 120,000 flights and were shown to then havea residual strength factor of 2. It seems clear from the results of the structural and flight testprogramme that development potential is available, and A.W.A. have recently hinted at an increase in maximum weight. Thismight enable the firm to offer the Argosy with the A.W.A. "Roller- mat" special cargo handling system and the full present payload;at the moment the special A.W.A.-designed loading system reduces the weight that can be carried by about 7 per cent.Where frequent stops have to be made, this penalty is easily offset by the reduced loading time that is involved; an average 3-4,000 lbcan be handled each minute. The system consists of pallets of various sizes, up to the widthof the Argosy's doors, which run on rollers set in light alloy conveyor sections. The pallet is restrained by lipped guide railsand by quickly adjustable end stops. More rollermat is bolted to the bed of the lorry, and the gap between the tailboard andthe fuselage is bridged by two girder sections of rollers. Only with exceptionally heavy loads would winching be required anda Dart engine, for example, can be manhandled from fuselage to lorry in about five seconds. If it is required, the tracks couldbe fixed permanently in position and some extra payload obtained by taking up the floor. (Concluded on page 59)
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