Sukhoi S-54 Sukhoi S-54 The Sukhoi S-54 was a series of three closely related aircraft proposals; the S-54 trainer aircraft, S-55 light fighter designed for export, and the S-56 carrier-capable light fighter. All members of the family resemble the Sukhoi Su-27 in general form, or the Sukhoi Su-33 more closely, but built around a single example of the Saturn AL-31 engine instead of two, and scaled down accordingly to a smaller layout. The design was offered to several potential customers, including South Africa and India, but was turned down. Development is apparently on hold, awaiting a launch customer. The project traces its
Sukhoi-Gulfstream S-21 speeds. As of 2012, the project had not received any funding for the 2013-2025 development period and appeared to be cancelled. Sukhoi-Gulfstream S-21 Sukhoi-Gulfstream S-21 was a projected Russian-American supersonic business jet. In the early 1990s, Gulfstream Aerospace and the Sukhoi Design Bureau began a joint effort to develop a supersonic small business jet, code named the S-21. Due to questionable market demand for commercial supersonic air travel, commitment to the project weakened and delays mounted. Gulfstream eventually dissolved the partnership, although Sukhoi continued work on the S-21. The S-21 would be capable of sustained cruise at Mach 2+ and