CFM56-7B General
Engine Type
CFM56-7B
Type
Turbofan Engine
Thrust Rating (lbf)
18,500 - 27,300
Manufacturer
CFM
CFM56-7B Program Milestones
Program Launch
January 1994
First Engine To Test (FETT)
May 1995
Flight Test on 747
January 1996
Engine Certification
October 1996
737-700 Entry into service
4Q 1997
737-800 Entry into service
1Q 1998
737-600 Entry into service
3Q 1998
737-900 Entry into service
2Q 2001


CFM56-7B (All Versions) Dimensions
Length
98.7 inch
Fan Diameter
61.0 inch
Basic Dry Weight
5,216 lb

Untitled Boeing 737-700
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Lauda Airlines Boeing 737-600




CFM56-7B

The CFM56-7B turbofan engine was initially developed to provide the Boeing 737 Next Generation (NG) operators with higher thrust, lower maintenance costs and improved efficiency than its predecessor, the CFM56-3. The engine has achieved outstanding reliability since its entry into service and is rated from 18,500 lbf to 27,300 lbf. The -7 has been subject to very demanding circumstances while still being able to achieve outstanding rates.

Due to its reliability it enabled the CFM56-7B-powered Boeing 737 the first aircraft in its class to be granted 180-minute Extended-Range Twin-Engine Operations (ETOPS) approval by the U.S. Federal Aviation Administration (FAA). Obviously this resulted in the ability of airlines to operate their aircraft with a far greater route-scheduling flexibility.

Besides commercial operators the CFM56-7B is operated by military customers as well. The U.S. Navy selected the engine to power its C-40A, a military 737 variant, for its Unique Fleet Essential Airlift Replacement Aircraft program.


Lion Air Boeing 737-900
Transavia Airlines Boeing 737-800
Examples of aircraft that are powered by the CFM56-7B

The higher performance offered by the engine is mainly due to its new 61-inch titanium wide-chord fan, a new core and low pressure turbine, all of which have been developed using state-of-the-art 3D aerodynamic design methods. Furthermore, the CFM56-7B incorporates a new-generation electronic engine control system, the FADEC, or Full Authority Digital Engine Control. In order to satisfy the most environmentally conscious airlines, the CFM56-7B is offered with a double annular combustor (DAC) on option.

The high-pressure turbine features blades made of the N5 single-crystal alloy, for significant improvements over the CFM56-3 engine, namely; lower operating temperatures with higher exhaust gast temperature (EGT) margins for greater on-wing durability, and a Thrust Specific Fuel Consumption (TSFC) which is reduced by more than 8%.

Another important design objective of the CFM56-7B was to reduce maintenance costs by 15% over the CFM-3C1 engine at a maximum thrust of 23,500 pounds. As said, since the -7B retained the exemplary reliability of its predecessor it was granted 180-minute ETOPS certification from the FAA less than two years after its introduction.

CFM56-7B Performance

Take-off Conditions (Sea Level)
CFM56
-7B18
-7B20
-7B22
-7B24
-7B26
-7B27
Max Take-off (lb)
19,500
20,600
22,700
24,000
26,300
27,300
Airflow (lb/sec)
677
696
728
751
779
782
Bypass Ratio
5.5
5.5
5.3
5.3
5.1
5.1

In-Flight Performance (35,000 ft-Mach=0.80-ISA)
CFM56
-7B18
-7B20
-7B22
-7B24
-7B26
-7B27
Max Climb Thrust (lb)
5,962
5,962
5,962
5,962
5,962
5,962
Overall pressure ratio
32.8
32.8
32.8
32.8
32.8
32.8
Max Cruise Thrust
5,420
5,450
5,450
5,480
5,480
5,480

Application
CFM56
-7B18
-7B20
-7B22
-7B24
-7B26
-7B27
Aircraft
 
 
BBJ

A 737 powered by CFM56-7B turbofan engines