|Passenger capacity of existing and|
future Boeing civil aircraft.
Yellowstone is a Boeing Commercial Airplanes project to replace its entire civil aircraft portfolio with advanced technology aircraft. New technologies to be introduced include composite aerostructures, more electrical systems (reduction of hydraulic systems), and more fuel-efficient turbofan engines (such as the Pratt & Whitney PW1000G Geared Turbofan, General Electric GEnx, the CFM International LEAP56, and the Rolls-Royce Trent 1000). The term "Yellowstone" refers to the technologies, while "Y1" through "Y3" refer to the actual aircraft.
Yellowstone is divided into three projects:
-Y1 is a Boeing Commercial Airplanes project to replace the Boeing 737 Next Generation product line. The Y1 is also known as the 737RS (for "737 Replacement Study").
Y1 is part of Boeing's Yellowstone project. It will be an entirely new aircraft rather than a further 737 derivative and will use much of the systems, structural and design technology of the 787. New technologies expected to be introduced include composite aerostructures and more fuel-efficient turbofan engines (however, other engine types are being researched). It is expected that Y1 will feature a wider cabin than the Boeing 737 or the Airbus A320, possibly even using a twin-aisle design (in contrast to the 737's single-aisle profile).
CFM International is currently proposing a new engine as a successor to the CFM International CFM56 family, currently known as the LEAP-X.
International Aero Engines has not yet made any proposals for a new engine; however, IAE shareholders Rolls-Royce and Pratt & Whitney are currently studying their own designs for future engines for the Y1 and Airbus NSR. Pratt and Whitney is proposing to use geared turbofan technology for the Y1 and NSR, while Rolls-Royce is proposing an open rotor engine. So far, Pratt & Whitney and Rolls-Royce have been promoting their new engines alone, rather than through the IAE joint venture.
The family may comprise direct replacements of the existing 737 models; however, Boeing is also investigating the possibility of two different types with different fuselage and wing sections — one in the ~100 seat market and the other in the ~200 seat market. In November 2009 Boeing submitted a patent application, released to the public in August 2010, that envisions an elliptical composite fuselage, and likely signals the company's planning for the 737 successor. Preliminary reports indicate that Boeing intends to couple the elliptical fuselage with an aluminum wing, a possible t-tail, and next generation composites. It is to feature a twin-aisle 2-3-2 layout, instead of single-aisle, like the 737's 3-3 layout.
The Y1 family will likely compete with Bombardier's new CSeries airliner, scheduled to enter service in 2013 with Lufthansa. Airbus was studying an all-new short-range aircraft, named the Airbus NSR in 2006 to compete with the Y1. As of 2011 Airbus is focusing on the Airbus A320neo, an upgraded version of the A320.
In January 2011, Boeing outlined plans for a 737 replacement that would arrive in 2020. Boeing CEO Jim McNerney stated in February 2011 that the company will develop the new airliner. On March 7, 2011, it was reported that Boeing intends to launch the 737 replacement at the 2011 Paris Air Show. It is expected to name the new airliner the Boeing 797 and will seat 180-250 passengers. The report, however, does not specify whether that is for a one-class or two-class layout configuration.
-Boeing Y2, to replace the Boeing 767 product line. It may also replace the 777-200. Y2 initially referred to the highly efficient, more conventional, baseline aircraft for the Sonic Cruiser, which was project "Glacier". It has now been built as the 787 and covers the 220- to 320-passenger market. It will compete with the Airbus A330, A340 and later A350 families.
-Boeing Y3, to replace the 777-300 and 747 product lines. Y3 covers the 300–600+ passenger market, and is expected to be the third Yellowstone Project aircraft to be developed. It will compete with the Airbus A380 family as well as the largest model of the A350 family, the A350-1000, scheduled to be introduced in 2015. In June 2010 it was reported that Emirates, which has a large fleet of 777s, was in discussions with Boeing about plans to develop a new airliner to replace the 777