Boeing 787 Dreamliner - Mark Wagner [64]
Boeing’s Phase 4 engine requirements issued at the start of 2004 outlined different engine builds covering the 55,000-to-60,000-pound-thrust range for the 7E7SR and baseline 7E7, and 70,000-pound-thrust for the 7E7STR. This unusual “1 1/2” engine need confused and confounded the industry, and out of nowhere seemed to suddenly challenge the basic simplicity of the original 7E7 family design goals. But Boeing was optimistic that the design refinements of the SR at the lower end and the STR at the top were allowing the thrust range to contract once more, and said the Phase 4 call did not signal that any “sort of decision has been made in terms of both the family members we have outlined. We still don’t know if it’s going to be one or two engine types, or one or two engine manufacturers.”
In fact, progress on define refinements was faster than expected, and by February 2004 Boeing decided to drop its exploratory “1 1/2” engine studies and revert to a single type instead. “The logic to stay with our original plan is overwhelming,” said Engineering and Manufacturing Vice President Walt Gillette. “When we began we had one engine build across the fleet, and that’s been our mainstay. We spent six to eight weeks looking at ‘what if?’ and we had a sort of engine-and-a-half family with a common core and two fan sizes. In the end we saw the value and simplicity of one engine build is somewhat better.”
The good news from Boeing’s perspective was that thrust requirements were indeed converging. “Part of that is because when we looked at the short-range version we saw it needs plenty of climb power, and the more we looked at the stretch, the more we saw it was a really efficient airplane that needed slightly less power than we thought,” explained Gillette.
The result was a simpler, quicker final round of engine selection evaluations. Engine makers were asked to submit best and final proposals at the end of March 2004, with the verdict due to be announced about a week later. It was a nerve-racking time for all concerned. Speculation mounted of it being an all-U.S. affair, with GE’s industrial might and Pratt’s clean sheet design winning through, while others foresaw GE securing its long-dreamed-of sole-source deal. To others, the aggressive technical and marketing stance of Rolls and the highly international aspect of the entire 7E7 venture dictated an almost natural place for the U.K. engine maker at the expense of one of the U.S. giants. There would be winners and a loser, but which would be which?
Rolls-Royce designed the Trent 1000 with a smaller hub diameter to achieve an inlet mass flow level as high as 2,670 pounds per second, yet still keep fan diameter to 112 inches. The force on each fan blade at takeoff is roughly equivalent to a load of almost 100 tons. Mark Wagner
The industry got its biggest clue that there would be only one loser, not two, in late March, when Boeing revealed that it would be offering an engine swap-out capability, allowing seamless interchangeability between aircraft. “This could be an attractive feature to the financing community,” said Bair. “One of the reasons we can do this is the capability of today’s avionics; we can make it all software-programmable.”
Bair was talking about the adaptability of the open-architecture-system philosophy being planned for the new jetliner, a massive step beyond the current state of the art in which engines and their controls were essentially “hardwired” into the design. Until the 7E7, specific airframe-engine combinations were generally for life; even if alternative engine choices were available, conversions were too long and too expensive to be worthwhile.
Finally, on April 6, 2004, the winners and loser were announced. GE and Rolls were selected, and P&W was out. The stunning news was greeted with jubilation in Evendale and Derby, respectively, and with obvious dismay in East Hartford, the Connecticut headquarters of P&W. As the only engine maker to submit an all-new design, P&W clearly held the potential advantage