U.S. Supersonic Commercial Aircraft Assessing NASA's High Speed Research Program (1997) / Chapter Skim
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2 REQUIREMENTS ANALYSIS
2 REQUIREMENTS ANALYSIS
Pages 26-45
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From page 26... ...
that impact market demand; international aspects of HSCT development; and the results of the QFD analysis the committee used to identify key HSCT design requirements. MARKET DEMAND The study statement of task calls for reviewing "existing studies of the likely demands for supersonic transports in light of the dependence of these demands on aircraft characteristics." Accordingly, the committee examined the methodology used in market demand studies, the basis for key assumptions (such as fuel costs)
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In other words, industry believes an economically viable market is likely to exist for an HSCT aircraft that meets the performance specifications of the TCA. Industry forecasts are based on several assumptions that limit the number of routes considered eligible for HSCT travel.
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Increasing the range of subsonic aircraft and improving in-flight communications and entertainment may reduce passengers' perceived "lost time" during subsonic travel and mitigate their willingness to pay premium fares for supersonic speed. Current forecasts do not seem to account accurately for this competition for passengers.
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Finding 2-1. Industry forecasts of market demand indicate that an HSCT consistent with TCA performance specifications will have a market size large enough to be economically viable.
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However, scheduling four crossings with a Mach 2.4 HSCT provides very little slack in the schedule to absorb delays caused by weather, congestion, or maintenance. Also, a fleet of Mach 2.0 HSCTs could be scheduled so that individual aircraft alternate between different routes, maximizing their utilization and providing a total number of seat miles that may not be significantly lower than the total number of seat miles provided by an equivalent fleet of Mach 2.4 HSCTs.
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From page 31... ...
From an airline scheduling perspective, an HSCT with a cruise speed as low as Mach 2.0 is likely to have productivity similar to a Mach 2.4 HSCT, assuming similar maintenance and servicing requirements. Impact of Design Range and Payload Aircraft range and payload correlate in an adverse way: increasing payload decreases range and vice versa.
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during supersonic cruise or a 1 percent increase in specific fuel consumption would reduce range by 1 percent. Also, because fuel weight is slightly more than 40 percent of maximum takeoff weight (MTOW)
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In Europe, Aerospatiale, British Aerospace, and Deutsche Aerospace are working together to develop advanced technology for a supersonic commercial transport. Publicly presented concepts focus on a cruise speed of Mach 2.0, but the Europeans are also developing airframe materials for higher speeds.
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At the 1996 World Aviation Congress, the Japan Aircraft Development Corporation (JADC) released the results of a government-supported conceptual design study that reviewed specifications for a next-generation supersonic commercial transport (Takasu et al., 1996~.
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NASA should continue to track the development of supersonic commercial transport technology worldwide. KEY PRODUCT AND PROCESS CHARACTERISTICS Translating customer needs and objectives into key product and process characteristics (which then lead to design requirements)
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QFD methodology requires selecting key product and process characteristics that can be quantitatively measured. Target values for each characteristic are located a row below Room 1 labeled "HSR Technology Targets, End of Phase II." The committee included MTOW and affordability as characteristics of the final technology configuration because the committee believes that minimizing MTOW by itself is not sufficient to meet the program objective of developing technology that will lead to an economically viable HSCT.
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~ C] ~ ~r _ _ ~ _ a' (D a~ u~ c~ ,_ ~ _ a' ~ I_ ~ _ ", 37 Integrated Aircraft 01 c 1 01^ O O _ _ _ _ _ _ _ _ ~ O O O _ _ _ _ _ O .
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The triangular "roof" of the QFD matrix, called the correlation room, is used to identify correlations between pairs of product and process characteristics. A filled circle implies a strong positive correlation; an empty circle implies a weak positive correlation; an "X" implies a weak negative or adverse correlation; and an "XX" implies a strong negative or adverse correlation.
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The key product and process characteristics from Figure 2-1 are ranked according to risk-weighted importance in Table 2-4. The ranking based on absolute importance is also listed in Table 2-4.
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In the most important group, affordability stands alone as the single most important characteristic. As shown in the "roof" of the QFD matrix, affordability is related to most other key product and process characteristics.
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A second QFD matrix could use propulsion and airframe requirements as customer requirements and relate them to integrated aircraft design requirements (range, payload, MTOW, affordability, etc.~. This two-stage analysis could provide a more accurate assessment of key product and process characteristics for the integrated aircraft.
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, acquisition costs, and operating costs. For example, the relatively low subsonic fuel efficiency and low seating capacity of the Concorde have contributed to its high cost per seat mile.
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The resulting technological nsk, together with market nsk, make it quite unlikely that HSCT airframe and engine manufacturers will make a product launch decision in 2006, based on the deliverables the HSR Program plans to make available before the program terminates in 2002. Finding 2-8.
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From page 45... ...
1996. Preliminary Sizing of a Supersonic Commercial Transport Between Mach 2.0 and 2.4, AIAA Paper 96-5589.
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