MEA321
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Difference Between CFM 56 And IAE V2500?

Fri Feb 27, 2004 4:10 am

Does anyone know the difference between the General Electric CFM 56 and the International Aero Engine V2500 which are used by the A320 family?

I am mostly interested in knowing the internal differences, but performance information is welcome!

MEA321
 
AAR90
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RE: Difference Between CFM 56 And IAE V2500?

Fri Feb 27, 2004 1:49 pm

I suspect little replies since there are many different variations of each engine and the difference would be mostly internal... too much to list here.

OTOH, I flew AA MD90s with V2528 engines and currently fly AA 738s with CFM56-7 engines. Operational performance is surprisingly different.

CFM56-7 max thrust is 26,000 lbs with a special exemption of 27,000 lbs for use at KSNA only. V2528 max thrust was 30,000 lbs on a considerably lighter airframe! V2528 starts quicker, spools up from idle much quicker, provides greater drag at inflight idle and is significantly quieter than the CFM56-7. But the -7 is more fuel efficient at altitude (at least on a 738 vs. MD90 comparison) and a bit more reliable (fewer engine monitoring faults).
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
gigneil
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RE: Difference Between CFM 56 And IAE V2500?

Fri Feb 27, 2004 5:34 pm

CFM56-7 max thrust is 26,000 lbs with a special exemption of 27,000 lbs for use at KSNA only.

That's interesting... Harms' website always listed AA as one of the few operators of the actual CFM56-7B27, as opposed to most with the -7B26.

Is that faulty data, or is the -7B26 really only 25,000 with a 26,000 lb bump?

N
 
MD-11 forever
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RE: Difference Between CFM 56 And IAE V2500?

Fri Feb 27, 2004 5:53 pm

"Is that faulty data, or is the -7B26 really only 25,000 with a 26,000 lb bump?"

The -7B26 is rated at 26.3 k Thrust. There is a special version called -7B26/B1, but the difference is only that this engine has a different mission profile for life time calculations, so no thrust bump or anything. Basically, the -7B engines are available with thrust bumps, but these designations are B1, B2 or B3 and the "baseline" thrust is always the one mentioned as a number after the -7B designator.

Generally, I can't give a statement about the difference between the two engines, although the CFM56 is my daily business. I am therefore biased that I know all the weaknesses of the engine we see in the shop. Nevertheless, I assume that the IAE must have even more issues, as the CFM56 is still the favourite choice of engines on applications where the two products are directly competing (A320 family).

Cheers, Thomas
 
AAR90
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RE: Difference Between CFM 56 And IAE V2500?

Sat Feb 28, 2004 9:25 am

That's interesting... Harms' website always listed AA as one of the few operators of the actual CFM56-7B27, as opposed to most with the -7B26.

Thanks to AA lawyers our Operating Manuals have gotten pretty *#%@ poor in the last decade or so. Officially everything was/is rewritten to "better correspond to the manufacturer's manuals" but what that really means is all descriptions are very brief and non-descriptive. My 738 OpMan lists the engines as simply CFM56-7.

Operationally, we have the capability of selecting a desired thrust rating [i.e. select what engine is on the plane that flight] with the choices being: 22k, 24k, 26k, and "27k Bump." AA's TPS [Takeoff Performance System] computer program normally makes the "optimum" selection for us including derated thrust settings for each of the first three "engines."

"27k Bump" is a special situation. As told to me during 738 transition training a few years ago, AA was the airline that pushed Boeing into getting the 738 noise certified at KSNA's second quietest noise slot [EE-exempt being the quietest] or AA would not order the plane. In doing so Boeing had to push the engine envelope a little... hence the 27k thrust setting and the associated limitation that is may only be used at KSNA and only in conjunction with the special FMS programming called "Quiet Climb." My understanding is that other airlines have been offered and some have accepted [and paid for] this option, but that it is "standard equipment" on AA's 738s.

Confused yet?  Nuts
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Jetmek319
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RE: Difference Between CFM 56 And IAE V2500?

Sat Feb 28, 2004 10:49 pm

MEA321,
I work here in the Airbus factory in Hamburg. If you can narrow down your request a bit I'll get whatever info you need. There are vast amounts of differences in the IAE V2500 series and the CFM 56-5's that are used in the Airbus A320 family, bit internal and external.
Never, ever moon a werewolf !!
 
MEA321
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RE: Difference Between CFM 56 And IAE V2500?

Sun Feb 29, 2004 3:13 am

With the IAE V2500 series and the CFM 56-5's there is a noticable difference from the outside. The V2500s seem more narrow and streamline.

I am just looking for the differences of the internal structure of each type. I know there are many different types within each series. However, is there a general schema that each engine (CFM and IAE) have?

For example, where is the bleed air taken from each type? How does bypass air differ engine noise?

Another question that I would like to have anwered is the general noise of the A320 family aircraft. There is a distinctive noise of most (I think all) A320 family aircraft from the ground when the pass overhead an observer at a low altitude of about 3000 feet (for example). It is a "humming" sound if that makes any sense. Is that for all type engines of the A320 family or only for a certain type?

Thanks for the replies!
MEA321
 
luv2cattlecall
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RE: Difference Between CFM 56 And IAE V2500?

Mon Nov 24, 2008 3:17 am



Quoting MEA321 (Reply 6):
Another question that I would like to have anwered is the general noise of the A320 family aircraft. There is a distinctive noise of most (I think all) A320 family aircraft from the ground when the pass overhead an observer at a low altitude of about 3000 feet (for example). It is a "humming" sound if that makes any sense. Is that for all type engines of the A320 family or only for a certain type?

I know B6's Airbii w/IAEs takeoff out of MCO, I always hear a buzzsaw noise...I believe it's due to the fanblade tips breaking supersonic.
.
 
gigneil
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RE: Difference Between CFM 56 And IAE V2500?

Mon Nov 24, 2008 3:31 am

LOL yes that's true... but this is thread is 4 years old now.  Smile

NS
 
tom775257
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RE: Difference Between CFM 56 And IAE V2500?

Tue Nov 25, 2008 6:45 pm

I have flown A319/320 with the various CFM engines, and the A320/321 with the V2500. Personally I prefer the CFMs. CFM56s are more reliable, rock solid, quick to start, quick warm up, and.... N1 indication! V2500s on the 320/1 need 5 mins warm up (rather than the CFM 3 mins), work in EPR (prefer N1 myself), smoke like anything after running so lots of nice organophosphate inhalation for the ground crew/flight deck, no auto start after failed start. Also, had a fume incident with the V2500 in flight. CFM 56 is overtemp EGT on start (at least on the A319/20) reduce the fuel by a percentage and try again, then a third time before giving up.

For the engineers, had an IDG failure on a V2500 today, they said compared to any other engine they work on, it is an utter nightmare to replace.

BTW CFM isn't just GE. It is a GE core, Snecma LP and another company that escapes me.

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