More information about the configuration of the sonic cruiser's engines has emerged
Boeing unveiled a scale model of its proposed high subsonic airliner, and provided the first opportunity for the industry to see the US manufacturer's current plans on the critical issue of engine installation.
Until the model was unveiled by Boeing Commercial Airplanes president Alan Mulally, the only information on the sonic cruiser's configuration came from artist's impressions which deliberately did not show the aircraft's underside.
While Boeing acknowledges the configuration is likely to be subject to much change as it is refined, the model provides an insight into the company's studies on how to install two high-thrust turbofans with the minimum of drag.
The intakes on the model resemble those of the Lockheed Martin F-16 fighter, although they are angled outwards. As with the military aircraft, the intakes stand off from the airframe and clear of the turbulent boundary layer, ensuring clean air enters the shallow S-ducts feeding the engines.
The US manufacturer says that it expects engine technology, future manufacturing and structures technology evolving over the next five to 10 years will allow the sonic cruiser to match the operating costs of today's 300-seat aircraft. Boeing is considering some radical ideas for the sonic cruiser's construction, including an all-composite wing.
Although Mach 0.95-0.98 is the publicly quoted target cruise-speed, there is also the possibility that the aircraft could be supersonic, as many industry observers had already suspected. "This aircraft has two [cruise speed] 'sweet spots', one of which could be a little bit faster than Mach 1," says Mulally.
The concept has been extremely well received in the marketplace, says Mulally: "One customer said it would take the first 300 aircraft- the first three years of production. We think there is a possible market for several thousand, maybe more."
According to industry sources, Boeing is expecting demand to be so strong that it may be able to charge premium prices to initial customers as they vie to purchase early delivery slots. Boeing is also studying the possibility of leasing, rather than selling, the aircraft to keep control of the after-market services business.
Boeing is already playing down earlier talk of a 2006 in-service date, with 2008 now seen as the earliest that the new aircraft will be available. "We are saying that deliveries will begin between 2006-2008, but we believe it will be towards the end of that timeframe," says John Roundhill, Boeing's vice president of marketing, new airplane programme. "It is highly probable it will be in service this decade."
Roundhill says that the design definition process will probably last at least a year, and "it would take some time to get the programme committed to launch". This would probably be around 18 months.
Source: Flight International
