parapente
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Cfm -56 Thrust Vc Cfm Leap-X Thrust

Tue Dec 21, 2010 2:35 pm

One (or at least I) supposes that the Leap-X engine developed by Cfm has been done so in very close conjunction with Boeing.That is where the many 1,000's of sales will come from and indeed the key customer they have to look after.On that basis one imagines that the core has been sized with Boeing first to mind.This is not to say they will not - indeed have not looked for other applications - of course they have.

AS such I wonder whether the predicted design thrust of the engine might not be telling us something.

This engine (or at least the core) is designed to be the engine on (shall we say) the Boeing 797.

The Boeing 797 (shall we say) starts serious engineering in the latter part of the 2020's. It will therefore incorporate everything that is being developed today.The finest and latest innovations in carbon construction. (or if you are being difficult!) The use of AlLi. Either way strides will be made against the old adversry "Weight".

Also the ever developing power of comuters will further refine wing dynamics. If not totally laminar - certainly better. Fair?

So a lighter aircraft that has a more efficient lift. OK?

The thrust range of Cfm 56 engines used on the 737 are between 19,500 lbs and 27,300 lbs

From the origonal announcement of the Leap-X engine the design thrust range is. 25,000lbs - 30,000lbs

Does that not tell us a litte about what size (Pax) range Boeing is planning to build the 797?

Remember the newer,lighter,more lift efficient. much more fuel efficient plane would need less installed thrust for a given size.No?

So based on this.I predict that the 797 is already inked in to start at the present 737-800 size and end at a 757 size.

If the above is true (no doubt I have made a howler somewhere!) are they leaving the lower sector to Bombardier and the like? Looking at it's "success" so far I believe that this is the intention.
 
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seabosdca
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RE: Cfm -56 Thrust Vc Cfm Leap-X Thrust

Tue Dec 21, 2010 3:15 pm

I think a new frame is not the only consideration. We know Boeing is reluctantly kicking around a 737 "NEO." This could point to additional payload range for the 738 and 739. Given the Leap-X's improvements in fuel consumption, what would the range of a 738-Leap-X be with two auxiliary tanks? Could it fly 757 TATL missions with a full load?
 
NWAROOSTER
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RE: Cfm -56 Thrust Vc Cfm Leap-X Thrust

Wed Dec 22, 2010 5:53 am

Quoting parapente (Thread starter):
The Boeing 797 (shall we say) starts serious engineering in the latter part of the 2020's. It will therefore incorporate everything that is being developed today.The finest and latest innovations in carbon construction. (or if you are being difficult!) The use of AlLi. Either way strides will be made against the old adversry "Weight".
Quoting parapente (Thread starter):
This engine (or at least the core) is designed to be the engine on (shall we say) the Boeing 797.

You talk about the Leap-X being ultimately developed for the Boeing 797, which you say will appear in the late 2020s.
Engine development and improvements are developed for aircraft NOW flying or that will be coming off the production line by 2015.
The aircraft of the late 2020s will leave the Leap-X engine in the dust..........   
Procrastination Is The Theft Of Time.......
 
parapente
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RE: Cfm -56 Thrust Vc Cfm Leap-X Thrust

Wed Dec 22, 2010 11:19 am

The aircraft of the late 2020s will leave the Leap-X engine in the dust

I respect your view - but I beg to differ.The core is going for a phenominal "leap" in technology.The core temperatures and pressures they are going for a huge compared to what is out there now (even military).The investment in this core will be designed to last for 20-30 years - as most are.

I accept that the method of pushing the cold air may change but not the core.It is only being developed for 2016 EIS due to the demands made for the 919 timetable. Indeed it has been pointed out on the general forum that the "Full spec" engine will not be ready at that time (Full Ceramic Blisks for instance).

But in truth I was only making a little observation.Simply that with future weight loss on aircraft by the increased use of composits and further inprovements of Aerodynamic efficiency - If the narrowbodied range was to stay the same you would need less installed thrust ie 15 -25K or so.But clearly the engine has been designed from the ground up to not be less, not even "the same"(thrust). But quite an increase.Since ( as I am postulating) the engine has been designed around (primarily) Boeings requirements. It suggests that the 737 replacement family wil be overall bigger.

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