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Fuel flow, IAE versus CFM


awirOn

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Hey guys, I just opened a new thread to avoid dealing with two problems in one thread. Let's get to the point, It feels like the IAE engines burn unusually more fuel than the CFM ones. Might this be something to be revised or is this another case of an "It's not a bug, it's a feature" ?

http://forum.aerosoft.com/index.php?/topic/85965-iae-engines-bugged/?p=616990

Thanks

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Yes the IAE engine burns much more fuel than planned. Mostly it needs one ton or more than I have calculated with PFPX.

Plus I have the feeling that the CFM engine is a bit underpowered. With an equivalent weight I need way more runway length than with IAE engines.

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I find the opposite. I just flew the same route out of Gatwick with CFM and then IAE engined versions. I used the same load for each flight, block fuel 14 tonnes. With the CFM engines the A319 reached top of climb just before Clacton VOR (CLN). Once stabilised in cruise over CLN with fuel remaining at 12.4 tonnes, fuel flow was 1560 kg/hr per engine.

With the IAE engines the A319 reached top of climb slightly sooner and using less fuel. Over CLN, fuel remaining was 12.8 tonnes and fuel flow was 1480 kg/hr per engine.

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  • Deputy Sheriffs

Four days and still no answer

What problem do you have with the fuel flow of the IAE? Could you post some more info like FL, speed, SAT, weight. We modelled the FF with the real charts from Airbus. I am not saying we are right and you are wrong but your statement is held very very general. You need to be a bit more specific here so we can help you.

And please do not compare our total Fuel Used with what PFPX says it should. This is not proof that anything is wrong on our side. I have real OFP's that state false tripfuels for real flights with real planes. It is just a bunch of calculations that take old/presumed parameters into the equation.

Thank you

ps, an aircraft engine is just like a car engine. 1.4 litre 122 BHP burns less than 2.0 litre 200 BHP.

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According to my observations the IAE engines use remarkably more fuel in contrast with CFM. I wasn't comparing the planned trip fuel of PFPX or real OFPs, but I did compare the behaving of both engines under roughly the same circumstances.

EDDH-EDDL - A319 CFM - FL260 - 201 nautical miles

124 pax, 3.91 cargo

On blocks - 5000kgs

TO - 4880kgs

T/C - 3840kgs

Cruise - SAT -32°C, GS 382, TAS 426, wind ~244/53kts

T/D - 3480kgs

Established ILS - 3200kgs

Left the runway - 3100kgs

On blocks - 3000kgs

Half an hour later:

EDDL-EDDH - A319 IAE - FL230 - 237nm - Mostly had tailwind

124 pax, 2.62 cargo

On blocks - 5400kgs

TO - 5240kgs

T/C - 4120kgs

Cruise level - SAT -25°C, GS444, TAS 408, wind ~256/37kts

T/D - 3380kgs

ILS - 2600kgs

Sadly forgot to note the fuel after vacating the runway

on blocks - 2280kgs

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  • Deputy Sheriffs

I still have to check your figures but we are on it.

What you should know is that the CFM will be remodelled so to take this Engine as a base can be misleading at the moment. We also checked all of our FF numbers with RW data collecting and Airbus charts so do not get your hopes up that something is extremely off here.

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