Each of these studies involved analysis and numerical optimization of the basic concept. At Langley the FLOPS computer program was modified to handle this geometry. At Stanford and Boeing, the PASS and ACSYNT codes were also modified to analyze this design. Existing engine decks representative of modern high bypass ratio engines were used rather than estimating the performance of future technology. This represents a rather conservative approach. Additional analysis with ADP engines and laminar flow control remains to be completed, but several aspects of the design suggest that gains from such technologies may exceed those obtained with conventional designs.
The figure below illustrates example results from one of these studies with the following assumptions:
Parameter Langley Boeing/Stanford Range 7000 nmi 7000 nmi Mach 0.85 0.82 Passengers 800 600 (tri-class) Field Lengths 12000 11000 # Engines 4 3 Approach 150 kts - Other constraints typical of FAR Part 25.
The results indicate that substantial reductions in take-off weight are possible, even though the concept was aimed primarily at resolving some of the problems associated with very large aircraft rather than providing much better performance.