Boeing will be working overtime to live up to the high expectations it is creating with the Dreamliner, both among airline customers and their passengers. Though addressing the needs and desires of both are often distinctly separate efforts, the 7E7 engineers are exploiting some interesting overlaps. The use of composite materials in the fuselage, for example, will not only keep the airplane’s weight down, making it more fuel efficient, but will also make the installation of larger, heavier windows less costly. The 19 x 11-inch windows, the largest on any current commercial airplane, will give passengers a view to the horizon.
The stronger composite fuselage also permits an increase in cabin pressure. The 7E7 cabin will be pressurized to 6,000 feet altitude, rather than 8,000 feet; the extra 2,000 feet made a huge difference to volunteers who helped with tests. Another environmental consideration: humidity. Airliner cabins are typically kept to Death Valley humidity levels—about 10 percent —to avoid moisture build-up in the bilges, but composites don’t corrode, so the 7E7 will be closer to the 20 to 30 percent minimum recommended by environmental health standards.
Boeing is pursuing numerous other advances. It is removing from the engine the gear-driven hydraulic pumps that drive the controls and landing gear, and valves that bleed compressed air to pressurize the cabin and keep ice off the wings, replacing these systems with electrical ones. Removing air bleeds from the engine boosts efficiency. If the engines have to feed the cabin with pressurized air, they must be bigger so they will run properly when all the bleeds are working at maximum capacity (for example, if one engine has failed). That means that they are pumping extra air most of the time.
Boeing will welcome passengers onto the 7E7 with