Sukhoi SSBJ could fly as early as 2002
by Vladimir Karnozov
According to Sukhoi general designer Mikhail Simonov, the Moscow- based aircraft design bureau has frozen the design of its proposed S-21 supersonic business jet. All technical documentation for the first prototype should be handed over to the Sukhoi experimental aircraft factory by the end of this year, with first flight expected in 2002.
The estimated base price for the S-21 is between $40- and $50 million. As with previous development work for the SSBJ program, the Russian company will fund construction of the first prototype from recent sales of Sukhoi fighters to India and China.
Commenting on French manufacturer Dassault Aviation’s estimates that supersonic business jet development would require a budget of between $500 million and $1 billion, Simonov said such a program would be markedly less in Russia given the country’s significantly reduced labor costs.
Simonov also argued that Sukhoi can build on its substantial research expertise from previous supersonic aircraft programs in Russia. In particular, Russia possesses a comprehensive database amassed during the U.S./Russian joint supersonic research effort on the Tupolev Tu-144LL jetliner flying laboratory. With more than 1,500 sensors fitted to the airframe, it has now made 24 flights, including four this spring. The Sukhoi team has its own experience with supersonic development, including the data it gathered during the development of the Mach 3, medium-range bomber known as the 100.
Determined to Make an SSBJ
Sukhoi is undeterred by reservations of Western companies (including Dassault and Gulfstream) to take a supersonic business jet to market. With a workforce of 5,000 people, it does not see a reason for cooperating with other aircraft developers, including other Russian design bureaus, on the S-21 project. "We only cooperate with TsAGI [Central Aerohydrodynamics Institute] on the design and a production plant on manufacturing issues," Simonov said. However, he also conceded that the company would be looking to gain Western partners to assist with international certification and product-support efforts for the SSBJ.
Since Sukhoi began working on the S-21 almost ten years ago, the airplane has undergone extensive design changes. Simonov indicated that the most critical challenge has been to find a powerplant that can meet today’s environmental requirements for subsonic aircraft. During feasibility studies, the Russian Aviadvigatel D-21 engine and the Rolls-Royce/Lyulka-Saturn model were dropped from consideration in favor of the Soyuz VK-21. This turbofan, with a takeoff thrust of more than 16,500 lb, was found able to meet FAR Part 36, Stage 3 noise requirements and is expected to comply with any upcoming environmental issues.
"Our task as airframe developers is not that difficult–just to wrap the engines up in a suitable cover," Simonov quipped. He added, however, that to stay within noise limits, the S-21 would have to take off at a derated power mode, and gradually increase the thrust when climbing away from the airport.
Powered by three VK-21s, the S-21 is expected to cruise subsonically at Mach 0.95 or supersonically at Mach 2.0, with equal rates of specific fuel consumption. With an operational range of more than 4,300 nmi, the airplane would be able to link almost any two major airports throughout the world with one stopover. Sukhoi said the S-21 will stay subsonic over land and go supersonic over water. Sonic-boom intensity for the S-21 cruising at Mach 2.0 is "less than 5 kg/sq m," Sukhoi claims.
Exterior dimensions of the SSBJ include a 125-ft-long fuselage and 72-ft wingspan. The cabin, 37 ft in length and about 6 ft in diameter, would accommodate up to eight passengers. The S-21, to be built largely of aluminum, will be distinguished by its long, thin nose and tail sections.
Explaining why the famous fighter house has been so persistently pursuing the supersonic business jet, Simonov said Sukhoi has been forced to diversify into civil markets due to the decline in military spending. "When we speak of a good fighter deal, we speak about $2 billion, perhaps $4 billion, whereas the potential market for the S-21 is estimated at $6.9 billion," he said. These estimates are based on market research studies by Fairfax, Va.-based Teal Group, which foresees a demand for 200 to 400 supersonic business jets over the next 20 years.
Maximum takeoff weight for the S-21 is projected at 114,197 lb. According to Sukhoi, Honeywell has been asked to develop an avionics suite for the aircraft.