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Aviation History
1957
1957 - 0081.PDF
1H January 1957 81 • respects on the airplane k is to displace. We have never yet•marketed a new airplane that wasn't an improvement in each • of these five respects." He chalked them up. First, capacity—Pup by 50 per cent. Second, operating cost. "This," he empha- sized, "is fundamental, and it has to be reduced by 20 per cent." £ Third, performance. There had to be a 20 per cent improve-•ment in range and in speed. The airlines wanted more than •improved costs—"you've got to do something to improve their•revenue." Fourth, comfort. This was something that couldn't •Pbe measured quantitively, but the interior had to look different,and you had to give people a rmoother, quieter ride. Fifth, safety. This was difficult to measure, except against the back-ground of the falling curve of accidents per million passenger- miles. "You have to fit better bad-weather aids, autopilot andflight control systems, navaids, brakes, reverse thrust, and so on." Mr. Kleinhans repeated that in their long transport historyDouglas had not yet marketed a new aeroplane that was not an improvement on the type it was replacing in each of thesefive respects. He referred of course to the DC-3, DC-4, DC-6, DC-7 and DC-8—each type separated by about six or sevenyears, and each (except, strictly speaking, the DC-8, which has still to be proved) better than its predecessor in the respectsoutlined by Mr. Kleinhans. These five desiderata for a new transport were, I felt, incon-testably well based; but I wondered how the DC-9 fitted them, rhat aeroplane, I knew, is to displace types like the DC-6 and[Ronnie, and to a lesser extent Convairs: without a doubt it would be an improvement over those aircraft in all five respects—yes, even in operating cost. And the DC-9 would, I felt, be at least as great an improvement over them as its turboprop com-petitors in all respects except perhaps one—operating cost over the short, 200- to 500-mile distances. Comparative Costs I put this to Mr. Kleinhans. He had not referred by name tothe DC-9, but he did so now. On the board he sketched out short/medium-range cost curves (on non-dimensional axes) fortypical rurboprops and "jets of the DC-9 class." For a short distance along the range axis the turboprop showed up best oncost: then, at a point where the jet curve began to fall more steeply, the turboprop curve began to rise sharply—until thetwo crossed at a point which could, from the rough proportions of scale, have been about 300 or 400 miles. Although he did not say so in as many words, it appeared thatMr. Kleinhans was conceding a small superiority in operating co3t to the turboprop—but only over the short distances. Beyondthose distances the jet appeared to become markedly and pro- gressively superior in cost. Pointing to the turboprop curve hesaid: "This is a specialized vehicle. But I'm not saying that turboprops are fools—I'm certain they're right for certainthings." He referred to what he called the "volte face of some of the turboprop proponents"—how they had once emphasizedthat their form of propulsion was the more economic over the longest ranges, but had changed their tune now. "Someone'sr»ght," he said, "and someone's wrong." The DC-9, he said, showed the five desired improvements,better in each respect than its turboprop competitors, though its job could be done better over the very short distances by whathe termed the "specialized vehicle." I thought he was perhaps making the turboprop look too specialized, but I accepted hispoints that the DC-9 showed better costs at any rate over the longer distances, and that for good measure you got for yourmoney the attractions of greater speed and superior comfort. One of his other DC-9 points is worth amplifying, becauseit is one not often raised in the jet versus turboprop controversy —perhaps because it is not easy to express simply. This isthat, if long field lengths are acceptable—say in areas like North America and Europe where good airports abound—the jet canbe shown to give a very marked superiority in economy over even the very fast, 425 m.p.h. turboprops. This argument isillustrated in the Douglas curve on the right below. At first I thought this was just a backwards way of saying that the jetneeds a longer runway. But I do not *hink this is so: basically the turboprop has roughly twice the take-off thrust of a turbojet ofcomparable compressor size. But the turboprop's ratio of cruise The Douglas transport which takes the palm tor low operating cost —the DC-6B. thrust to take-off thrust is comparatively low. And if you canshow that, using a jet and turboprop of equivalent take-off thrust, that the jet will still reap the reward of better economy over thelonger distances, how much more economical would the jet be using an engine with a lower take-off thrust? Cruise thrust,hence speed, would still be relatively high, but using a much lighter and more economical jet. These thoughts, I shouldexplain, are as expressed by me and not by Mr. Kleinhans, who just put them into my mind. Then, as I expected, he mentioned what I think is one of themost compelling arguments for the DC-9, and one which I know Douglas have been selling hard to the airlines—particu-larly to those who have bought DC-8s. This is the "paired jet transportation system concept"—and it is not, I think, justanother of the many "systems concepts" which the Americans delight in devising. The proposal that an airline should employa small jet to feed and act as partner to its big jets appears to be natural and logical, especially if the aeroplanes concerned comefrom the same shop and are to a great extent technically and operationally interchangeable. This is the kind of partnershipthat Douglas are propounding for the DC-8 and DC-9. I asked Mr. Kleinhans whether he did not consider that theRolls-Royce Avon RA.25 would be ideal for the DC-9. "We've looked at all the engines," he said, "—Rolls-Royce, G.E., Bristol,Pratt and Whitney, and they all make a fine airplane. But with different engines you get different airplanes—you just can't helpit. The engine is the rock or the sand on which you build the thing." They just had to get to that "continuity of design"between the DC-8 and DC-9—airframes as well as engines—and the fact is that the Pratt and Whitney J52 is a scaled-down J57. I began to see that there was more behind the DC-8/DC-9relationship than vague talk about "technical interchangeability." Systems, components, equipment and accessories would all workthe same way and in many instances be taken out of the same store.I came back to my first question, putting it in a different way. "If you had a big order today for the DC-9, would you go aheadwith it?" The reply was straightforward and immediate. "I don't thinkso," said Mr. Kleinhans—Douglas didn't quite work that way. The decision to go ahead would be a consideration of the man-agement "who are pretty good at judging this kind of thing." Douglas weren't like Socrates, "who put his head in his handsand worked out that if a stone was heavier it fell faster." They looked at the thing "in the light of demand, philosophy—evenwhether the airlines ought to have it or not." (Coming from any- where but Douglas that might have sounded pompous.) And theynever moved in on a deal unless it was a technical decision first, business second. "We don't let ourselves be influenced by wantsor hopes or wishes—just the facts. There's no magic about the way we do things." Douglas appear to be in no hurry over the DC-9. My impres-sion was that they are quietly mulling it over among themselves, but are nevertheless trying it out forcefully on the airlines—whoare in no hurry either. As Mr. Kleinhans said, referring to both Douglas and the airlines: "You can only eat so fast, and you MM »CITY fH) ISM lOOd soo Mc, .85 * BLOCK SPtED 1000 ?000 3000 4000 RANG* (SIAT. Ml.) Left, the Douglas view of the relationship between aircraft speed and range. The block speed of a Mach 2 supersonic trans- port is seen to be only 915 m.p.h. at its maximum range of 950 miles. Right, illustration of the Douglas argu- ment that, provided a longer take-off dis- tance is acceptable, the medium jet shows a better ratio of revenue-to-operating cost than the turboprop. (IV. or. COST - • (IV. or. COST • ^""Vc, = 300 MPH __ TURBOJET ___ TURBOPROP yT VCT = 550 MPH TAKI-Off OtfTANCi
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