CFM56 vs V2500 A320 series

[tom775257]

I get the impression that the V2500 is a poorer engine than the CFM56 for a few reasons mainly anecdotal, I hope you can correct me:

Engines often not reaching predicted life span, methods including packs off and flexing when ever possible to save engine life. Not tankering at all if it takes even 1deg C from the flex temp.

Specifically avoiding base training in V2500 because each TOGA application takes a good chunk of engine life away.

Very long start up time with extensive dry cranking before fuel flow - I heard this was because initially they had bearing failures due to lack of oil pressure, so the ECU is programmed to crank for a while to get the oil pressure up before light-off.

Longer warm up time (5 mins) requiring sometimes to hold after a fast taxi.

A personal one: EPR gauges - annoying! I fly both engines, so I find myself always just flying N1, much the same as every A320 series pilot I have spoken to.

Anecdotally the CFM is a much more robust engine, almost impossible to flame out with water ingestion etc. highly reliable and will happily reach expected time on wing. Excellent FADEC relight control making using continuous ignition a waste of time.

The only advantage I have heard about the V2500 is that it is a little less thirsty than the CFM56.

So please can someone set me straight, moving almost exclusively to flying V2500 powered aircraft now - which annoys me.

[javelin]

Yep - all of the above is correct !

The cranking is due to a bowed rotor caused by heat distortion on short turnrounds. The cranking 'restraightens' the rotor.

The other problem with the V2500 is variable touchdowns on autolands.

If you are LHS - get used to closing the thrustlevers at 50' provided you have the normal energy margin on VLS otherwise you will do the 5.....5.....5.....5.... dance down the runway :eek:

The flap setting on the V2500 is slightly different to the CFM which also affects the flare.

I much prefer the CFM.

[Torquelink]

At least the LLPs on the V2500 are all the same life (20,000 cycs) which makes SV planning easier

:ok:

[electricdeathjet]

Yeah....... And the CFMs look better too! :}

[the rim]

hi from the blokes who fix em you dont have to open the tin....sorry plastic....very often on the v2500 in line maint at least and as far as looks they look like mini 524's mmmmmmm

[On-MarkBob]

The CFM is a bit of a 'tractor' engine. More of a cowled turbo-prop, I think. It gets you off the ground better than the V2500 but then stops. The altitude capability is less than the V2500, which is more of a precision instrument. The V2500 is thus far more fuel efficient, which matters alot these days. Although the V2500 A320 takes longer down the runway, the aircraft climbs higher sooner and is more often flying in the 'clear air' than that of the CFM. Thus the CFM also takes the penalty of bouncing around in the weather more often which in turn contributes to the cost of operation. The V2500 gets my vote every time.

Bob.

[Dani]

I also prefer the CFM, but I agree that the IAE is most probably a bit more modern. It uses a lot less oil - with fuel I cannot see a difference.

Something strange from a pilots point of view, is how the spooling up and down is programmed on the IAE. Sometimes you undershoot speeds by 10 kts or more after a level off. I never saw that on a CFM Airbus. Since this characteristic has nothing to do with engine, I guess it's a software programming problem. Cranking during start-up has been significantly reduced with the younger IAEs. It's 30 seconds now like on a CFM.

I think there is also a price difference between the two, IAEs lower, that's why everyone is ordering them now, especially the LCC.

Dani

[Brian Abraham]

flap setting on the V2500 is slightly different to the CFM
Nerd question. Why is that the case?

[Dream Land]

My vote for the IAE, no more extra spool time (not like the old ones), plenty of power at altitude on the A5.

[winglit]

CFMs are oil drinkers. It's not uncommon to top up with about 4 quarts after a return 3 hr sector. And you have to pour the oil in slowly. Too fast and you end up with a puddle of oil on the floor. This has been resolved with the later ones though with a revised oil tank.

V2500 are much more fragile with a bird ingestion. A CFM could take in an Ostrich at take off and keep going, but if a V2500 swallowed a sparrow, it's a fan change.

Never done a fan trim balance on a CFM, only V2500, several times.