Reader Response #1 + Thesis
The CFM56 series is a collection of high-bypass turbofan aircraft engines manufactured by CFM International (Global Engine Maintenance, 2019), a 50-50 collaboration between GE Aerospace and Safran Aircraft Engines (MTU Aero Engine, n.d). Supplying more than 30,000 units to about 500 clients globally, it is the most dominant engine used on aircraft (CFM International, 2017, as cited by Mwanalushi, 2021). Among the series, the CFM56-7 is the latest engine developed (CFM International, 1995). According to CFM International (2024), it is the sole engine “for the Boeing Next-Generation single-aisle airliner”, with over 15,000 CFM56-7 produced to power Boeing-737 aircraft, earning its title as “the most popular engine-aircraft combination in commercial aviation history”. In addition, the engine has accumulated 25 million engine flight hours in just the span of six years of commercial operations, setting yet another record for having “the fastest accumulation of flight hours in commercial aviation history” (CFM International, 2024). The CFM56-7 features a “three-dimensional aero design, a high-efficiency wide chord fan, advanced electronic engine control, and active clearance control systems”, offering substantial cost advantages from a significant cutback in fuel consumption and maintenance expenses (CFM International, 1997).
The CFM56-7’s notable achievement is well-deserved, thanks
to its merits in efficiency and cost-effectiveness.
Firstly, the CFM56-7’s specific fuel consumption is estimated
to be 8 percent lesser than the CFM56-3 (CFM International, 1996). OpenAI
(2024) described specific fuel consumption as the “amount of fuel consumed by the
engine for producing a certain amount of thrust or power over a specific period
of time”. Each percent reduction in fuel consumption can yield annual savings
of as much as $15,000 per aircraft (CFM International, 1996). With that, it can
be inferred that the CFM56-7 is more economical than its predecessor.
In addition, it was reported in 1996 by CFM International that
the maintenance cost for the CFM56-7 is expected to be 15 percent lower than
the CFM56-3 at the same thrust. An article by Aircraft Commerce (2003) states that a
“performance restoration” for the CFM56-7 is estimated between $875,000 and
$900,000 while a complete overhaul costs about $1.1 to $1.2 million. On the
other hand, the “performance restoration” on CFM56-3 costs from $860,000 to
$910,000, and the overhaul costs $1.4 to $1.5 million (Aircraft Commerce,
2006). It is evident that conducting maintenance on the CFM56-7 is much cheaper than the CFM56-3.
Despite its edge over its earlier version, the CFM56-7 has shortcomings
when compared to its successor, the LEAP-1B, which is developed with an identical
design to the CFM56 series (Memon, 2023) by CFM International (GE Aerospace,
n.d). In terms of thrust performance, the LEAP-1B can produce 23,000 to 28,000
pounds of thrust (Memon & Walker, 2024) while the CFM56-7 can only produce 18,500
to 26,300 pounds of thrust (CFM International, 1996). Since “in level flight,
when thrust is increased, the aircraft speeds up and the lift increases” (Federal
Aviation Administration, n.d), the LEAP engine will provide better velocity and
lift in the same conditions than the CFM56-7.
Another aspect in which the LEAP-1B surpassed the CFM56-7 is
the bypass ratio. The LEAP-1B engine has
an outstanding bypass ratio of 9:1 (Memon & Walker, 2024) while the bypass
ratio of the CFM56-7 lowest-thrust-rated version is 5:1 (Aircraft-Commerce,
2008). An article by Monroe Aerospace (2023) states that “high-bypass turbofans
are typically more efficient than their low-bypass counterparts” as they utilize
less fuel and produce lower amounts of gas emissions. Having said that, we can
say that the LEAP-1B is more fuel-efficient while producing significantly lesser
discharge than its older counterpart.
In conclusion, the CFM-56 engine series is well-received in
the aviation industry and has significantly contributed to the aerospace
industry with its performance. As technology advances, it turned to act as the foundation
for improvement for the LEAP series.
References
Aircraft Commerce. (2008). Aircraft-Commerce.
https://www.aircraft-commerce.com/wp-content/uploads/aircraft-commerce-docs/Aircraft%20guides/CFM56-7B/ISSUE58_CFM56_7B_SPECS.pdf
Aircraft Commerce. (2023). Maintenance cost analysis:
JT8D-200, CFM56-5B/-7 & V.2500.
https://www.aircraft-commerce.com/wp-content/uploads/aircraft-commerce-docs1/Maintenance/2003/ISSUE%2028-MTCE-B.pdf
Aircraft Commerce. (2006). CFM56-3 maintenance analysis
& budget.
https://www.aircraft-commerce.com/sample_article_folder/maintenance_engineering_1_sample.pdf
CFM International. (1995, May 22). CFM56 engines continue
to lead the industry; new CFM56-7 begins ground testing on schedule. https://www.cfmaeroengines.com/press-articles/cfm56-engines-continue-to-lead-the-industry-new-cfm56-7-begins-ground-testing-on-schedule/
CFM
International. (2024, April 9). CFM56 - CFM international jet engines.
https://www.cfmaeroengines.com/engines/cfm56/
CFM International. (1997, October 14). Thy places $280
million CFM56-7 order.
https://www.cfmaeroengines.com/press-articles/thy-places-280-million-cfm56-7-order/
CFM International. (1996, December 7). CFM56-7: An
in-depth look at the new industry leader.
https://www.cfmaeroengines.com/press-articles/cfm56-7-an-in-depth-look-at-the-new-industry-leader/
CFM International. (2024, February 24). CFM56-7B fleet
achieves 25 million engine flight hours.
https://www.cfmaeroengines.com/press-articles/cfm56-7b-fleet-achieves-25-million-engine-flight-hours/
Federal Aviation Administration. (n.d.). Chapter 5 -
Aerodynamics of Flight.
https://www.faa.gov/sites/faa.gov/files/07_phak_ch5_0.pdf
GE Aerospace. (n.d.). CFM LEAPEngine family.
https://www.geaerospace.com/commercial/aircraft-engines/cfm-leap
Global Engine Maintenance. (2019, July 27). CFM56-7B. https://global-engine.com/cfm56-7b/
Memon, Dr. O. (2023, February 24). The engine of the
future: How does the CFM leap differ from the CFM-56?. Simple Flying.
https://simpleflying.com/cfm-leap-engine-advantages/
Memon, Dr. O., & Walker, S. (2024, September 6). How
CFM LEAP engines enhance the performance of the Boeing 737 MAX. Simple
Flying.
https://simpleflying.com/cfm-leap-engines-enhance-performace-boeing-737-max/
Monroe Aerospace. (2023, December 1). Low vs high bypass
turbofan engines: What’s the difference? One Monroe Aerospace.
https://monroeaerospace.com/blog/low-vs-high-bypass-turbofan-engines-whats-the-difference/?srsltid=AfmBOop4ZGcr6mZWW-cdLG1awlbSfKTi7qs2SL1JhmxJk_VVpLrinqqk
MTU Aero Engines. (n.d.). CFM56: Powering the Airbus A320
family and the Boeing 737. https://www.mtu.de/engines/commercial-aircraft-engines/narrowbody-and-regional-jets/cfm56-2/-5b/-7/
Mwanalushi, K. (2021, March 29). Turning turbines:
Why CFM56 is the reigning engine of choice. Aviation Business News.
https://www.aviationbusinessnews.com/low-cost/cfm56-aviation-aircraft-engine/
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