XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Sept 27, 2016 15:40:56 GMT 1
Yet, I cannot help noticing that they talk about engine reliability, not performance (fuel burn ...). Well, it's a press release (i.e. marketing talk). Fact is the LEAP engine is flying with an open compressor, which leads to higher fuel burn. We just don't know the number. |
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s543
in service - 2 years
Posts: 3,957 
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Post by s543 on Sept 27, 2016 17:29:22 GMT 1
Yet, I cannot help noticing that they talk about engine reliability, not performance (fuel burn ...). Well, it's a press release (i.e. marketing talk). Fact is the LEAP engine is flying with an open compressor, which leads to higher fuel burn. We just don't know the number. The number will come out - but it is too early .... probably Pegasus signed an agreement not to publish the data too soon if they are ...  |
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eta3
In Parts Built
Posts: 7
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Post by eta3 on Sept 28, 2016 15:38:13 GMT 1
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Sept 28, 2016 15:56:13 GMT 1
FlightGlobal has a quote saying fuel burn in on spec. I don't think it's so clear ... "The joint venture has pledged to deliver the Leap-1A with 15% lower fuel consumption than the CFM56. The press released issued on 27 September says the engine has achieved a “double digit” fuel consumption improvement. Asked to clarify, CFM says, 'yes, we are showing a 15% improvement with the airlines'. The pledge is 'CFM 56 minus 15%'. The written release claims a 'double digit' improvement (read 10% or a little more). You are right, though, that 15% was claimed verbally. I don't think it is possible for the LEAP to be at specs in operation as long as its compressor is open in flight. I also tend to doubt marketing claims, especially when verbal only. 10% is a more reliable number for the moment. |
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eta3
In Parts Built
Posts: 7
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Post by eta3 on Sept 28, 2016 16:20:43 GMT 1
What's not clear about:
"The joint venture has pledged to deliver the Leap-1A with 15% lower fuel consumption than the CFM56." and 'Asked to clarify, CFM says, “yes, we are showing a 15% improvement with the airlines'."
I'm not sure why the doubt on a statement to the press by a joint venture of two publicly traded companies. On the other hand, the only source that LEAP engines are still flying around with compressor bleeds open is one poster on airliners.net and his "rumor mill". Just as it'd be wise to take CFM statements with a grain of salt, the same would be prudent for random internet forum posts.
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s543
in service - 2 years
Posts: 3,957
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Post by s543 on Sept 28, 2016 16:32:48 GMT 1
It is still not very clear.
They are comparing to CFM56-5A1 or CFM56-5B5 - it is a significant difference worth around 5% .....
Comparison to PW1000G would be more interesting.....
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mjoelnir
in service - 2 years
Posts: 4,089
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Post by mjoelnir on Sept 28, 2016 16:52:26 GMT 1
What's not clear about: "The joint venture has pledged to deliver the Leap-1A with 15% lower fuel consumption than the CFM56." and 'Asked to clarify, CFM says, “yes, we are showing a 15% improvement with the airlines'." I'm not sure why the doubt on a statement to the press by a joint venture of two publicly traded companies. On the other hand, the only source that LEAP engines are still flying around with compressor bleeds open is one poster on airliners.net and his "rumor mill". Just as it'd be wise to take CFM statements with a grain of salt, the same would be prudent for random internet forum posts. And that CFM already has advertised a change in exactly that area a fan/intermediate compressor high compressor mismatch would need work. |
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Sept 28, 2016 17:04:02 GMT 1
What's not clear about: "The joint venture has pledged to deliver the Leap-1A with 15% lower fuel consumption than the CFM56." and 'Asked to clarify, CFM says, “yes, we are showing a 15% improvement with the airlines'. Well, you are conveniently skipping the only written statement made by CFM the same day, claiming only to have achieved a 'double-digit' gain for the moment. The pledge is indeed 15%, but if that figure had already been reached, then the press release would have said so. It is very important that they could not write that, since a written statement is much more committing than a verbal assertion that they are 'seeing' 15%. Another noticeable point is that the customer (Pegasus), while praising the engine for its reliability, did not say a single word about fuel burn. Please remember that we had the opposite situation when LH received its P&W engine : they said that there were a lot of issues (then), but they were happy that fuel burn reached and even exceeded promises. What is not said is sometimes as important as what is said ... For the sake of clarity, I have little doubt that CFM will eventually achieve 15%, but I think we can safely draw the conclusion that they still have some work to do. |
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s543
in service - 2 years
Posts: 3,957
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Post by s543 on Sept 28, 2016 18:36:12 GMT 1
The whole statement (and no-saying) is so vague that it is suspicious.
They might be happily on 15% over the 25 years old CFM-5A1 or even more on older CFM56 from 737-classic.
i.e. saying above CFM56 does not say much. IF there would be "current" CFM56 it is a different statement.
We must not forget that CFM56 started it's distinguished career in 1974.
And there was a LOT of improvement during those 42 years !
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Oct 1, 2016 13:04:37 GMT 1
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