McDONNELL DOUGLAS (MDC) and NASA are working on a proposal for an X-plane programme in which a manned, quarter-scale model of the company's blended wing-body (BWB) airliner design would be flight tested. Officials say that the project is continuing, although it is not known whether it will survive Boeing's acquisition of MDC.

MDC senior fellow Dr Robert Liebeck says that company president Harry Stonecipher has a "handshake agreement" with NASA Administrator Dan Goldin to pursue the blended wing-body X-plane programme, struck before MDC agreed to Boeing's $13.3 billion take-over bid.

The programme, costing about $100 million, would involve two quarter-scale models of MDC's BWB-1-1 design. The full-scale airliner would carry 800 passengers 13,000km (7,000nm) at Mach 0.85, powered by three 275kN (62,000lb)-thrust very-high-bypass turbofans, and would have a wingspan of 85.3m and a maximum take-off weight of 373,300kg.

Liebeck says that plans call for a first flight within 30 months, with external lines and aerodynamic loads defined by the end of the year. Low-speed windtunnel testing is to begin in February, and high-speed testing in April, both at NASA Langley.

A 5.2m-span remotely piloted model of the BWB-1-1 is scheduled to be flown by Stanford University in March.

To reduce costs, MDC is proposing using the cockpit tub and systems of a two-seat F/A-18, including fly-by-wire flight controls, as the basis for the blended wing-body X-plane. The primary engine candidates are three 30kN Pratt & Whitney Canada PW306 turbofans, Liebeck says. The X-plane will have a range of 20,500km, and MDC is proposing using the aircraft to set a one-stop round-the-world record. The aim of the programme will be to demonstrate the Blended wing-body design's transonic performance and flying qualities, he says.

Before the Boeing take-over bid, Liebeck says, Douglas Aircraft had asked whether service-entry of a blended wing-body airliner could be accelerated from the planned 2010-2020, to 2005, but the project's future is now uncertain, he admits. MDC's three-year NASA-supported study has shown that the BWB-1-1 would be 27.5% more fuel-efficient than a conventional 800-seat design.

MDC is now working on an 82m-span, 600-seat blended wing-body airliner. Although the design range is 13,000km, Liebeck says that the aircraft "can make money" at 3,700km range, and 400 seats, which could allow one airframe size to meet the requirements of today's stretched and "shrunk" versions of conventional aircraft.

Source: Flight International