High speed civil transport

Figure 1-44 The High-Speed Civil Transport (Courtesy of Boeing)...

NASA is developing a special polyimide (PETI-5) for the High Speed Civil Transport (Mach 2.4) whose lifespan is more than 60 000 hours at 177°C with excellent property retention at this temperature. 

In 1971, Johnston suggested that anthropogenic emissions of NOx from a proposed fleet of supersonic transports (SSTs) could cause a reduction in ozone due to the set of chain reactions (10) and (11). At the time, a fleet of 500 SSTs flying seven hours a day in the stratosphere by 1985 was projected, and based on that, Johnston (1971) showed that the emissions would be expected to lead to significant ozone depletion. This was never realized because of the much smaller use of SSTs than projected. However, a subsequent proposal for the development of a high-speed civil transport (HSCT) raised some of the same issues, as discussed in the following section. 

B. HIGH-SPEED CIVIL TRANSPORT (HSCT), ROCKETS, AND THE SPACE SHUTTLE... 

Bekki, S and J. A. Pyle, Potential Impact of Combined NO, and SO, Emissions from Future High Speed Civil Transport Aircraft on Stratospheric Aerosols and Ozone, Geophys. Res. Lett., 20, 723-726 (1993). 

Pitari, G., V. Rizi, L. Ricciardulli, and G. Visconti, High-Speed Civil Transport Impact Role of Sulfate, Nitric Acid Trihydrate, and Ice Aerosols Studied with a Two-Dimensional Model Including Aerosol Physics, J. Geophys. Res., 98, 23141-23164 (1993). 

Weisenstein, D. K M. K. W. Ko, J. M. Rodriguez, and N.-D. Sze, Effects on Stratospheric Ozone from High-Speed Civil Transport Sensitivity to Stratospheric Aerosol Loading, J. Geophys. Res., 98, 23133-23140 (1993). 

The applications for addition polyimides are for electronic/electrical materials such as printed circuit boards and insulators, as matrix resins for structural composites in aircraft and as thermal insulation materials. Recently the market for polyimide based structural composites has suffered from the termination and reduction of military aircraft programs. However, the possible emergence of the High Speed Civil Transport program (HSCT) may offer an opportunity for addition polyimides (2). 

Perhaps the biggest thrust for the development of high performance polymers over the next 10 years will be in the aerospace industry where materials will be required for a fleet of high speed civil transports (supersonic transports). At a speed of Mach 2.4, an aircraft surface temperature of about 150 to 180°C will be generated. The life requirement of materials at these temperatures will be about 60000 hours. Many different types of materials such as adhesives, composite matrices, fuel tank sealants, finishes and windows will be needed. These materials must exhibit a favorable combination of processability, performance and price. The potential market for these materials total several billions of US dollars. 

Danilin, M.Y., J.M. Rodriguez, M.K.W. Ko, D.K. Weisenstein, R.C. Brown, R.C. Miake-Lye, and M.R. Anderson, 1997 Aerosol particle evolution in an aircraft wake Implications for the high-speed civil transport fleet impact on ozone, J. Geophys. Res., 102,21,453-21,463. 

Baughcum, S. L., and Henderson, S. C. (1998) Aircraft Emission Scenarios Projected in Year 2015 for the NASA Technology Concept Aircraft (TCA) High Speed Civil Transport. NASA-CR-1998-207635. 

High speed civil transport United States commercial supersonic transport combustor exhaust nozzle operate at temperatures > l,600°C(2,192°F)for combustor operate at temperatures > 800°C (1,472°F) for nozzle time at temperature > 10,000 hrs... 

The next generation of high speed civil transports (HSCTs) is designed to carry 250-300 passengers at supersonic speeds [5]. The European version of this aircraft (a second generation Concorde) has a proposed speed of Mach 2.05, consistent with transatlantic operation, whereas the US plane has a proposed speed of Mach 2.4 for transpacific operation. Estimated surface skin temperatures will increase from 110°C to 177°C simply as a result of the speed difference. The operational life at these elevated temperatures... 

PM Hergemother, Polymeric materials for high speed civil transport . Trends Polym Sd 1996 4 104. 

Actually, a few years ago, Hergenrother [86] stated the precise requirements of the technology for high speed civil transports (HSCTs) the sealants must exhibit a combination of properties such as elongation, moderate peel strength, fuel resistance and performance for 60000 h at 177 °C. He said that the most popular commercially available fuel tank sealant that can be used at a temperature of around 177°C is based upon poly(3,3,3-trifluoropropyl methylsiloxane), but this product may degrade after continued exposure to high temperature. 

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