Luis777
Topic Author
Posts: 81
Joined: Sun Aug 29, 2004 3:16 am

What CFM-56 Stands For?

Sun Aug 29, 2004 4:01 am

Hello, all what I know about this engine is that CFM is a joint venture between General Electric and SNECMA. General Electric use to name their engines CF and I think that the C is for Compressor and F means Fan, but I'm not sure. About SNECMA I know that they always use the M for "Moteurs" in French language. Does someone can correct me please?
Talking about the numbers I think that GE choose the 6 because this engine could be a derivate of their CF6 engine, but why 6? and SNECMA choose the 50 because they utilize numbers like M80, M60, M100, etc. What do you think about this? I made a search on the web but I didn't find anything.

Regards

LG
 
air2gxs
Posts: 1443
Joined: Mon Jun 18, 2001 1:29 pm

RE: What CFM-56 Stands For?

Sun Aug 29, 2004 5:31 am

From the CFM Website:

CFM is not an acronym, so it doesn’t stand for anything. The company (CFM), and product line (CFM56), got their names by a combination of the two parent companies’ commercial engine designations: GE’s CF6 and Snecma’s M56.

The internet is a wonderful thing.

http://www.cfm56.com/excel/index.html
 
Luis777
Topic Author
Posts: 81
Joined: Sun Aug 29, 2004 3:16 am

RE: What CFM-56 Stands For?

Sun Aug 29, 2004 1:13 pm

Thanks a lot Air2gxs, I didn't notice that info on cfm56 page the first time I entered there, what a shame :p .

And yes, I agree, the internet is a wonderful thing.

Regards

LG
 
Buzz
Posts: 694
Joined: Sun Nov 21, 1999 11:44 pm

RE: What CFM-56 Stands For?

Sun Aug 29, 2004 6:48 pm

Hi Luis777, Buzz here. Well, in the mid '80s when UAL replaced the JT3D engines on the DC-8's with CFM56 engines we figured that CFM stands for "Creates Forward Motion". I think i recall that it stood for the english equivalent of "Commercial Fan Motor".

It took a while to get used to the new engines, they were a lot slower to start (that's a mighty big fan to accelerate) and Oscar O. had a handful of melted turbine blades to show us what happens when a pilot starts the engine with a tail wind, and clicks the fuel lever on without checking to see if the N1 is turning. (don't do that)

And the fuel nozzles ("injectors" back then) would cause quite a loud Buzz - enough to feel it in your chest - while the engine was accelerating up to idle speed. But when it was at idle you could walk up beside it (carefully!) to look for leaks and she'd be running smoothly.

g'day
Buzz Fuselsausge: Line Mechanic by night, DC-3 Crew Chief by choice, taildragger pilot for fun.
 
phollingsworth
Posts: 635
Joined: Sat Mar 06, 2004 6:05 am

RE: What CFM-56 Stands For?

Mon Aug 30, 2004 12:36 am

Talking about the numbers I think that GE choose the 6 because this engine could be a derivate of their CF6 engine, but why 6?

While I can offer no insight into why GE says that the naming is a CF6 derivative, I can say that the CFM-56 is not a CF-6 derivative in any sense other than it is a HBTF that came after the CF6. However, GE has historically named their commercial turbofans CF (CF6, CF34). I do know the project sat stagnate for over 10 years and that the GE-SNECMA partnership was a risk reduction choice. However, I don't know if both GE and SNECMA had independent programs for this thrust class prior to the formation of CFMI. The CFM-56 core is from the F-101, i.e. the B-1 bomber motor.
 
DfwRevolution
Posts: 8654
Joined: Sat Jan 09, 2010 7:31 pm

RE: What CFM-56 Stands For?

Mon Aug 30, 2004 8:11 am

While I can offer no insight into why GE says that the naming is a CF6 derivative, I can say that the CFM-56 is not a CF-6 derivative in any sense other than it is a HBTF that came after the CF6

GE, and other manufactures, build off the newest or previous generation of engine technology. The CFM56 built of the CF6 and M50, the GE90 built off the CF6, and the GENEX will build off the GE90.

The CFM56 and CF6 probably share very little, but they have a common design philosophy
 
phollingsworth
Posts: 635
Joined: Sat Mar 06, 2004 6:05 am

RE: What CFM-56 Stands For?

Mon Aug 30, 2004 10:35 am

The CFM56 and CF6 probably share very little, but they have a common design philosophy

In the sense that the CFM56 shares the same design philosiphy with the TF39 and TF/CF34. The primary reason that the GENEX is based off of the GE90 tech is GE hasn't built an entirely new military jet engine since the GE90 was introduced and its subsequent upgrades. I believe the GP7000 core is also based off of the GE90
 
N243NW
Posts: 1597
Joined: Thu Jul 24, 2003 4:29 am

RE: What CFM-56 Stands For?

Wed Sep 01, 2004 11:41 am

I'm not sure about the CFM part of it, but I think I remember reading somewhere that the 56 represents the turbofan's 5.6:1 bypass ratio. Correct me if I'm wrong.
-N243NW  Big thumbs up

[Edited 2004-09-01 04:50:29]
B-52s don't take off. They scare the ground away.
 
buckfifty
Posts: 1278
Joined: Tue Oct 16, 2001 4:05 pm

RE: What CFM-56 Stands For?

Wed Sep 01, 2004 12:03 pm

There are a few derogatory versions of the name which are used by engineers and pilots alike. Unfortunately, too many kids read this site, cannot pollute their dear minds...
 
cdfmxtech
Posts: 1319
Joined: Wed Jul 05, 2000 11:37 am

RE: What CFM-56 Stands For?

Wed Sep 01, 2004 12:45 pm

From CFM56-7 Factory Maintenance Training Manual

It is a product of CFMI. CFM International is a company
jointly owned by GENERAL ELECTRIC (GE) of the USA,
and SOCIETE NATIONALE D’ETUDE ET DE
CONSTRUCTION DE MOTEURS D’AVIATION
(SNECMA) of France.

Draw your own conclusions
 
prebennorholm
Posts: 6445
Joined: Tue Mar 21, 2000 6:25 am

RE: What CFM-56 Stands For?

Thu Sep 02, 2004 7:48 am

SNECMA's engines are all named M plus a number.

They never finished development of their M56 engine project, which was mostly intended for the Dassault Mercure airliner.

Due to delays with M56 development the Mercure went to the air with P&W JT8D power, and it consequently never met the originally intended range capability.

They did develop a good fan unit, but went into great troubles with the M56 core. Then they joined forces with GE who had had Uncle Sam pay for development of the GE F-101 engine for the B-1 bomber.

Basically they joined the core of the F-101 with the fan of the SNECMA M56 engine project.

In GE terms I think that CF means "Commercial Fan engine", but I'm not sure. Anyway it's a fact that commercial fan engines from GE are named CF-x.

So basically they assembled the name CFM56 the same way as they put the engine together.
Always keep your number of landings equal to your number of take-offs
 
brons2
Posts: 2462
Joined: Tue Sep 25, 2001 1:02 pm

RE: What CFM-56 Stands For?

Thu Sep 02, 2004 3:22 pm

There are a few derogatory versions of the name which are used by engineers and pilots alike. Unfortunately, too many kids read this site, cannot pollute their dear minds...

Well hell, I appreciate a little adult humor, email them to me!
Firings, if well done, are good for employee morale.
 
prebennorholm
Posts: 6445
Joined: Tue Mar 21, 2000 6:25 am

RE: What CFM-56 Stands For?

Fri Sep 03, 2004 8:07 am

While the name CFM56 is quite logical, then - slightly off topic - what does V2500 stand for?

"V" is the roman number five, which was the original number of manufacturers forming the consortium International Aero Engines (IAE). They were already reduced to four before the first test run, since FIAT stepped out.

"2500" is the originally intended max sea level thrust expressed in British pounds divided by ten.

So it would have been logical if an IAE V2530 had been named IAE IV3000 instead.
Always keep your number of landings equal to your number of take-offs

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