Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
Aviation and the Global Atmosphere
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7.10. Supersonic Transport Aircraft
Other reports in this collection
Supersonic transport aircraft are not new. In the 1960s and early 1970s, there were three major supersonic transport projects in Europe, the United States, and the
Soviet Union. Only one of those projects, the Concorde, was completed and continues in revenue service-and only between Western Europe (London and Paris) and
the eastern U.S. seaboard (New York and, until recently, Washington). Only 13 of these aircraft are in airline service, including charter operations and demonstration
flights. The ground and flight operational acceptability for this type of aircraft has been demonstrated worldwide.
The life development of Concorde aircraft now suggests they could continue in service for an additional 10-15 years. The levels of exhaust emissions produced by
Concorde's Olympus engines [EI(NO x ) = 18] is higher than could be achieved now but is commensurate with the design knowledge of the 1960s. With a limited small
fleet and an average aircraft utilization of 600 hours per year, these aircraft do not appear to constitute a major environmental concern, although they must be
considered in aircraft fleet mix scenarios in view of the Concorde's higher cruising altitude.
The Concorde operates for passengers prepared to pay high fares. Improvements in materials, structural, and systems technology that are available or currently being
developed could make a second generation of supersonic aircraft more widely affordable. Studies have concluded that an aircraft with between 250 and 300 seats
cruising at Mach 2 to 2.4 (at altitudes between 16 and 20 km) is most likely to be successful (Shaw et al., 1997). To make such aircraft effective for the long overseas
routes that benefit most from the increased speed and maintain viability with regard to viewpoint of sonic booms, the projected range must be at least 8000 km (and
possibly 10400 km). Studies have examined a wide range of speeds and concluded that speeds higher than Mach 2.4 offer little gain in block time, whereas they
exacerbate airframe materials and propulsion problems, hence increase technical risk (Zurer, 1995). Prior projections concluded that aircraft with a cruise speed of
Mach 2.0 to 2.4 were feasible for entry into service in 2005, and a hypersonic vehicle cruising at Mach 5 might enter service by about 2030 (Zurer, 1995). Events have
shown that these projections were optimistic, and it is unlikely that a new Mach 2 to 2.4 vehicle will enter service much before 2015. By the same token, required
research for the hypersonic vehicle and its economics would make entry into service of a hypersonic vehicle unlikely before 2050-and possibly later unless scheduling
and airport curfews could be accommodated to demonstrate higher cruise speed benefits. Therefore, the focus of the remaining discussion is on vehicles cruising at
speeds up to Mach 2.4.
The Concorde has already demonstrated the practicality of Mach 2.05 as an achievable cruise speed with aluminum alloys for the basic structure. For speeds above
Mach 2.2, more exotic materials would be required including titanium alloys and organic composites for structural items and more complex air intakes. At speeds
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