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Aviation History
1963
1963 - 2122.PDF
FLIGHT International, 5 December 1963 923 improved the noise situation. The 727 centre engine had a long duct and inlet sound suppressors and for that reason "it sounds quieter than it actually is." Mr Steiner speculated that the aft engine's forward noise component was shielded by the wing in landing approaches. All-weather operation, operational flexibility and high profit-potential were also requisites for the short-range jet. The second part of the Boeing representative's presentation dealt with certain design features. The 727 had no aft side door, contrary to the early demands of some airlines. This was specifically because of Boeing's fear that ground crewmen would slam their equipment into either the flaps or the engines during ground service operations. An important consideration in the use of the ventral door as employed on the 727 was that it did not require a vestibule, so that much valuable space could be saved. Space saving also was the reason that the 727 had a single galley amidships and all electronics located "downstairs." Boeing's new transport "probably had the highest packing factor of any new aircraft." A forward retractable stair was provided, although "Mr Patterson doesn't believe that passengers should be allowed to walk on the ground." The Seattle company originally objected to airline demands that an APU be provided, but they were now quite happy with the idea. During the recent world-wide tour the Boeing party had encountered 110° weather at Karachi. "The APU resulted in the 727 being the ccolest spot on the airport." A slide was next presented showing comparative body cross- sections and plan forms of several transports. The 727 had the same upper deck size (cross section) as the 707 not because, as everybody believed, the company were saving on tooling costs, but because they wanted "the correct size." After all, with a 1,000m dollar programme, Boeing were not too concerned with several million dollars of tooiing. The major error of the Trident, thought Mr Steiner, was that its body was six inches too narrow. The speaker then turned his attention to the Caravelle and presented several slides which he believed proved that the 727 was the right-sized aeroplane. In building the 727, Boeing did not try to build the fastest transport in the world; but it could outrace the 707-320B at any altitude and the 720 at low altitudes. Speed, however, was useful. Mr Steiner observed that for a 25-aircraft fleet, an airline might save ?1.5m for a 5min saving in block time. Boeing did "attempt to build the smoothest aircraft in the world." Believing they had achieved this goal, Mr Steiner recalled that on the 727's recent tour they had unbelievably flown through very hard rain at the astounding altitude of 32,000ft. They were struck by lightning twice, and although they sped along at 600 m.p.h. through turbulent air they did not once have the seat-belt sign come on. The 707/720 family had achieved a "dispatch reliability" of 95.43 per cent in 1962. The 727 had to be better, since it made more stops to cover the same distance. The 727's World Tour The third part of the presentation covered the 727's world tour. A total of 139 flights were made in 194hr 16min. Total mileage was 94,483. Several people advised Boeing along the way that they "were nuts" to attempt such a comprehensive tour less than nine months after the first flight. Of special note in Mr Steiner's eyes was Jhe fact that there were no accompanying supporting aircraft— "one manufacturer had a DC-4 stocked with spares accompany his aircraft round the world"—and there were no spares sent in advance to any destination. All parts were on board, as were 15 to 20 ground crewmen. The men frequently had less than three hours' sleep a night, but not a single delay was caused by mechanical trouble. Two boost-pump failures could be cited as minor problems. The speaker then contrasted the Boeing experience with that of the Trident, noting that they had chanced upon the aircraft at Karachi while it was suffering a three-hour delay caused hy hydraulic leaks. [Hawker Siddeley Aviation's de Havilland division state that the Trident did not suffer from hydraulic leaks while it was at Karachi, nor was it delayed.—Ed] After some further incidental comments the meeting was opened for questions. With the emphasis on rapid ascent and descent, a member of the audience inquired about cabin-floor angle during these phases of flight. Boeing had deliberately designed the wing incidence with respect to the body to favour the descent case, replied Mr Steiner. People did not mind a very substantial angle a * take-off, but psychologically there was great resistance to having me nose too low. In the 727 the floor angle was about two to three Agrees at maximum let-down rates. They had bettered 7,000ft/min during the tour while descending over Japan. This was the occasion when the aire aft was let down from 35,000ft to 3,500ft in a little over 4min, leading to some speculation in the Press that it was an uncontrollable dive. Engine inlet distortion was next questioned. Mr Steiner said that he would be remiss if he left the impression that the programme had never had its own peculiar problems. On the very first flight the centre engine su-ged at unstick, and for a number of flights there was a totally unexplainable and "insidious" recurrent separation of flow. After many unsuccessful attempts to pinpoint the trouble, a TV camera and closed-circuit system were installed. Tufts were placed in the duct. These led to the discovery that there was almost instantaneous separation and reattachment of the flow in No 2 engine. The frequency of occurrence prevented its being detected by ordinary means. A duct change was made; but, even now, "No 2 is not the best engine at take-ofT, due to losses in efficiency, although at cruise it is just as good as the others." Break-even Sales Point The speaker was not so candid about the break-even sales point. Stating that he would be speaking out of his field in this regard, it appeared to him that one was perpetually chasing this point. The number must be over 200 a'reraft. Mr Allen had recently said that it was about SI,000m of sales, a figure which has been nearly reached with 147 sales to date for $800m to $900m. Mr Steiner guessed that ultimate sales would exceed 500 aircraft. "The prize does not go to the one who is there first, but to the one who is still there last." It was at this juncture that a Douglas representative rose to his feet. Remarking that he had promised himself beforehand not to say anything, he stated that he had been so baited by the Boeing man's remarks that he could not in good conscience remain quiet. "Using Boeing's own formula," he cited a long list of facts which he claimed tended to prove that the DC-8 was a better product than the 707—and "That takes care of that aeroplane." He then went on to claim that it was "hooey" that there existed such a thing as a uniquely correct or "magic" formula which only the Boeing company employed. Every aeroplane, the Douglas man contended, was the result of, and required many, many trade-offs. Each company saw things slightly differently, and the emphasis which Boeing placed on leading edges was misleading to an audience. He referred to an earlier Boeing slide which indicated that the 727 had 128 component devices (screwjacks, cylinders, etc) associated with high-lift features. The DC-9 had exactly 24, and it was sheer nonsense for anyone to claim that the 727 was more reliable than the DC-9 in this regard; it couldn't possibly be. Regarding the use of leading-edge devices, the Douglas man—who had introduced himself as being a senior aerodynamicist—stated that the DC-9 would never employ them. Not slats, slots or Kriigers?, asked Mr Steiner. None of these, answered the aerodynamicist. The issue was left, with a case of Scotch riding on the outcome. Before returning to his seat for the first time (he was to rise several times during the evening) the Douglas aerodynamicist essentially defied the speaker to discuss the flaps-up stall char acteristics of the 727. Subsequent questions also centred on this point, and it was obvious that many members of the audience were distinctly concerned over this problem, which had been encountered with such tragic consequences on the BAC One-Eleven. [The One-Eleven crashed following an approach to the stall with flaps deflected 8° and the e.g. at 0.38 SMC—Ed] Boeing were quite concerned with the "super stall," as Mr Steiner termed it. By super stall he meant going beyond the g-break at 30° to 40° angle of attack. They were "very familiar" with the One-Eleven accident and had studied it in minutest detail. Although the speaker did not explicity so state, it appeared to many members of the audience that the 727 could also get into a similar condition. This conclusion was drawn because of Mr Steiner's emphasis on avoidance, and of his comments on how there had been adequate enough warning of the incipient condition on the 727: "You must recognize the phenomenon and you must not get into it." In the design, "one must make tail effectiveness as good as possible." The 727 had been flown by everybody, it was licensable (in Boeing's opinion) in its present condition and it was "far better than any [other] aft-engined high-tail aircraft.'' On several recent flights the 727 had been taken "beyond the One-Eleven point" [presumably Mr Steiner meant an angle of attack of 30° to 40°—Ed] in terms of angle of attack. How, asked somebody, did one perform a flaps- up stall on the 727? Mr Steiner replied that the first warning was (Concluded on page 934)
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