II. DESIGN FEATURES A. General SST Performance and Comparisons The supersonic transport (SST) is the generally-accepted name for a commercial (as compared with military) passengercarrying airplane capable of sustained level flight at supersonic speeds. There are at present two such airplane designs in operation, preparatory to commercial certification, and one under construction. The two flying airplane designs are the British/French Concorde and the Russian Tu-144. The prototype under construction is the United States' Boeing 2707. The major performance features of these three designs are compared in Table 1, and a pictorial overlay of the three appears in Fig. 1. A comparison of the B2707 with the 747 subsonic "jumbo" jet is also of interest (see Fig. 2). The United States SST (the Boeing 2707) is substantially different from both the Concorde and the Tu-144 in the following areas: Speed: The B2707 cruises faster than the others (about 1800 mph vs. about 1400 mph for the Concorde and about 1550 mph for the Tu-144). This higher speed capability requires the use of titanium as a basic structural metal for the B2707, rather than the conventional aluminum alloys used for the lower-speed designs. Capacity: The B2707 carries over twice as many passengers as either of the other two designs. This added capacity requires a larger, heavier, more powerful airplane. Target Date for Commercial Certification: The B2707 is expected to arrive on the international scene in 1978, as compared with 1973 (estimated) for the Tu-144 and 1974 for the Concorde. This allows the B2707 to employ generally more up-to-date technology, and therefore demonstrate considerably improved performance over the Concorde (and probably the Tu-144) in such key areas as noise reduction, air pollution control and overall seat-mile costs. These elements are discussed in greater detail in Section III. One feature of the United States program in this regard is its separation of the prototype and production phases, extending the interval between "first flight" and projected "in-service" dates as compared with both foreign models (see Table I). This "time-saving" by the foreign manufacturers . means, however, that they are committed to developing production aircraft which are similar in all major respects to the prototype, regardless of any non-optimum technical or operational characteristics which may be discovered during |