CFM International's newest engine, the CFM56-7, went to test on schedule at Snecma facilities in Villaroche, France, on 28 April, paving the way for first flight on a modified Boeing 747 flying testbed in January 1996, and engine certification the following October, less than 40 months after program launch.
CFM International (CFMI) is a 50/50 joint company of Snecma (Safran Group) of France and General Electric of the United States.
The engine had operated for a total of more than 30 hours through the end of May and achieved more than 27,000 pounds (120 kN) thrust. Test results for specific fuel consumption, fan flow, EGT (exhaust gas temperature) margin, and fan and core speed characteristics have met or exceeded pre-test predictions. The engine has also completed power calibration and preliminary performance runs. Over the next few months, the engine will continue to run performance evaluation and fan mapping tests.
The CFM56-7, rated from 18,500 to 26,400 pounds (82 to 117 kN) takeoff thrust, is the exclusive powerplant for next-generation Boeing 737-600/-700/-800 series aircraft. CFMI has taken a global cost of ownership approach to developing the engine and, thus, it offers better performance, improved acoustics, an optional low-emissions combustor, and lower cost of ownership than CFM56-3 engines for the current-generation 737. For example, overall maintenance costs will be reduced by as much as 15 percent compared to the CFM56-3C1. CFMI has also undertaken initiatives internally that will significantly reduce shop costs over the next five years, enabling the company to hold down airline acquisition costs.
The CFM56-7 is a state-of-the-art engine that features solid, wide chord fan blades, 3D aero design, new materials technology, an advanced FADEC (Full Authority Digital Electronic Control) system, and has available an optional low emissions Double Annular Combustor (DAC). The engine incorporates the CFM56-5B/P core and low pressure turbine, in addition to the existing CFM56-3 gearbox and a new booster. The core, low pressure turbine, and booster result in lower operating temperatures and higher exhaust gas temperature margins. As a result, the CFM56-7 will provide operators longer time on-wing. Performance improvements being certified on the CFM56-5B will also be incorporated into the CFM56-7.
Ground testing for the CFM56-7 engine equipped with a double annular combustor, which was launched on the Boeing 737-600 by Scandinavian Airlines System (SAS) earlier this year, is scheduled to begin in October 1996.
The engine will enter service with Southwest Airlines in October 1997 on the 737-700; the CFM56-7-powered 737-800 enters service in March 1998 with Hapag Lloyd, while the 737-600 is scheduled to enter service with SAS in August 1998.