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Aviation History
1964
1964 - 0241.PDF
158 FLIGHT International, 30 January 1964 Pictured at Shannon is one of the three Super Constellations owned by Intercontinental, the American-registered charter company which, based at Luxembourg, is associated with the Carvair operator Interocean AIR COMMERCE . . . SUPERSONIC ROUND-UP OF all the problems faced by aircraft designers and operatorsfew have ever approached that of the supersonic boom. SST designs have now been on the drawing boards in manufacturers' project offices for at least ten years, yet a universal ruling on a humanly acceptable overpressure is no nearer to being a reality. In an effort to capture some of the long-range transport aircraft market of the 1970s through being first in the field with an SST, the Anglo-French manufacturing alliance have settled for the Concorde design which they say is built just within the tolerable boom limit. Faced by the threat of the Concorde, United States manufacturers are naturally inclined towards an aircraft with just a little bit more range and payload accommodation to compensate for their project's apparent lateness. In fact, as with similarly competitive projects in the past, the effect of the better operating flexibility of this specifi- cation has been to attract more "orders" than the firm Concorde project on which metal is actually being cut. This state of affairs led to wild rumours that France wants to withdraw from the Concorde enterprise—all strenuously denied. As this issue went to press there were reports that the range of the Concorde, which Dr Russell of BAC said last December could not be stretched beyond London/Paris - New York, is in fact now thought to be capable of a ten per cent increase. This would be achieved by developing the Olympus—possibly increasing the total cost of the programme—to improve payload-range capability to bring New York within economic reach of most European cities. It would be against all the established principles of design if there was no way of profiting from engine development or to gain some- thing in the event of a pessimistic view having been taken of the boom effect. What is a Tolerable Boom? In early February the Federal Aviation Agency is to begin a six month long test in the Oklahoma City area to determine the public's acceptability of sonic boom overpressures at the levels predicted for SST operations. Mr Gordon M. Bain, FAA deputy adminis- trator for supersonic transport development, in announcing the boom study said: "A substantial amount of effort has already been devoted to exploring the sonic boom in the past, both in this country and abroad (Flight International, June 6, 1963, for a review of earlier work). We now have a clear picture of the relationship between boom intensity and such factors as speed, mass, and altitude of the aircraft generating the boom. We can predict the boom quite accurately on the basis of these factors, and measure it precisely with ground instruments. The present boom intensities being used in SST design were established largely on the basis of experimental work by aeronautical researchers. Now it is time to build on the foundation of this work and to investigate for likely community- reaction problems that will arise from SST operations." An F-104 Starfighter will generate the booms over Oklahoma City. Testing will begin with overpressures of around llb/sq in and be inflicted at progressively decreasing intervals during the first week until there are seven runs a day between 0700hr and 1800hr. For the second week the pressure will be stepped up to 1.51b/sq in. This last figure is the maximum cruising boom specified in the FAA's request for design proposals. A public interviewing programme will be conducted throughout the Oklahoma City area during the latter phases of the study by the National Opinion Research Council of the University of Chicago. Another important aspect of the tests will be a close investigation into the possible effects of the boom on buildings. Four houses of various types and in different parts of the city have been rented and fully instrumented for the purpose. In anticipation of public concern, the FAA say they will investigate any reasonable claim for damages as a result of the tests, and the Government will pay for any verified damage. A report of the experiment will be prepared by the FAA, NASA, and the Air Force at the end of the tests and it should be issued by the end of the year. The US Manufacturer's Proposals The FAA is now studying the competing SST design and programme proposals of Boeing, Lockheed, and North American on the air- frame side, and Curtiss-Wright, General Electric, and Pratt & Whitney for the powerplant. Mr Gordon Bain has said: "Even at this stage it is very evident that the manufacturers have devoted intensive effort to the development of their proposals. Now we commence the most comprehensive evaluation in the history of commercial air transport." The first part of the evaluation is being conducted by a team of 210 drawn from the FAA, NASA, USAF, US Navy, CAB, and the Department of Commerce. The group is expected to finish its work by early March. Ten American airlines will then conduct independent evaluations, and prepare their views in time for a joint meeting with the Government agencies scheduled for March 25 and 26. If a clearly superior proposal emerges by this stage, the FAA administrator will announce the selection of an airframe and engine manufacturer to proceed with development. Failing a clearly superior proposal the contestants will be asked to carry on with their separate investigations for another year. If none of the proposals meets the design criteria in the request for proposals, the programme may be redirected. Although the substance of the proposals is not being published just yet, Mr Bain has said that the cruising speed of the US design is unlikely to be more than Mach 2.5, or 1,750 m.p.h. If this is so, then its speed advantage over the Mach 2.2,1,450 m.p.h. Concorde will not be so great as expected, and the differences in journey times even less. An accurate idea has not been given of the current thinking with regard to range, only that it will not be less than 4,000 miles. Presumably it will be sufficient for direct flights between European capitals and New York. Reports in the US industry say that Boeing's submission—the Model 733—features variable-sweep wings, while Lockheed and North American are concentrating on fixed delta wing designs. What Industry Can Afford The December issue of the Boeing Magazine contained the text of a statement by William M. Allen, president and chief executive of Boeing, given to the aviation sub-committee of the senate commerce committee in October outlining BoeingVfinancial position and the extent to which the firm could become involved in an SST pro*
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