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gbfra
Posts: 427
Joined: Tue Sep 05, 2006 5:50 am

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 6:22 am

Quoting Gsosbee (Reply 40):
Who is the model then?

European and Asian carriers.

Quoting Gsosbee (Reply 40):
On the Europe to US routes, competition is based more on frequency and thin routes, so as long as there are savings, no matter how small, 2 engines will be the preferred way.

Who are the most successful carriers across the Atlantic? Those who have 4-haulers or those who haven't? The fact that close-to-bankrupt US carriers can't afford to buy 4-haulers doesn't mean that there is no place for 4-haulers. Just ask BA, LH and AF. They can afford to buy them.
 
aircanada014
Topic Author
Posts: 1224
Joined: Sun Oct 09, 2005 2:24 pm

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 8:12 am

Don't get me wrong everyone I love B747s especially B747-400s. I really love flying those big jumbo jets.
 
lehpron
Posts: 6846
Joined: Tue Jul 10, 2001 3:42 am

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 8:36 am

Quoting Cingularity (Reply 21):
it seems to me that you are eventually going to run out of room to fit one large engine under the wing

This assumes bypass ratio can only be increased with greater diameter fans. But the bypass ratio is the ratio of "mass flow rate (meansured in mass of air per unit of time)" of what goes around the core divided by what goes through the core. Widening the blade chord could increase the ratio as well, which negates needing a larger diameter. There is more about an engine's efficiency than just the bypass ratio.

Quoting KC135TopBoom (Reply 16):
The way I see it, the B-747-800i will be the last 4 engine passenger liner

You mean subsonic?  Wink

Assuming all variables in question were accounted for, I'm less inclined to believe a supersonic/hypersonic as a twin or even a quad set. Most transport designs I've seen have 4-6 engines, some even have over 20 (not rockets).

But yeah, I agree and think that most subsonic airliners from here on out may be twins; we've covered all thrust ranges, now it's just a matter of making them even more efficient to satisfy future requirements, customer and regulatory.
 
ZKSUJ
Posts: 6889
Joined: Tue May 18, 2004 5:15 pm

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 2:07 pm

Quoting Zeke (Reply 39):

Never met a pilot wanting fewer engines, that is for accountants

I cannot agree more with that statement.  Smile I personally prefer 4 holers as opposed to 2, but thats just me. The 748 will be a dream to fly for those who get the opportunity.
 
UAL777UK
Posts: 2378
Joined: Sun Nov 20, 2005 1:16 am

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 4:26 pm

Quoting PlaneHunter (Reply 5):
VS and Branson are all about marketing - many people around world are in "environmental panic" now, perfect for earning money, just a question of marketing. People who attacked Branson for his pro-4-haulers marketing should be careful with praising him too much now...

So does that mean that VS will cancel their order for the 380 as many predicted when they deferred delivery?
 
Burkhard
Posts: 1916
Joined: Fri Nov 17, 2006 9:34 pm

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 5:51 pm

If a smaller engine had the same weight to thrust ratio and the same fuel to trust ratio than an engine twice as powerful, the 4 engines would be more economical than the two engines - because every twin jet has to carry more power than a quad.

Currently they aren't - the CFM56 is a rather old design, built in masses for a relatively cheap price - and it still will take quite some years until the new technology of the expensive big engines come to this low price market. If I imagine an engine with GENX blades and Trents three stages and a by pass ratio of 8, it would not only make the 737NNG/A320NNG much more efficient, but also make A340 sized long range very competitive.

The A340-300(X) definitively shows the limits what can be reached with CFM56-technology, anything bigger currently needs engine that come from the big twin portefolie, even two Trent500 could handle a wide body middle range airliner.
 
zvezda
Posts: 8886
Joined: Sat Aug 28, 2004 8:48 pm

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 6:05 pm

Quoting Juventus (Reply 4):
I'll like to think once UA retires their 747-400s, they will be done with 4 engine aircraft

UA have seven routes (to NRT, PEK, and PVG) where the governments don't allow them additional frequencies and a fleet of twelve VLAs is optimal to operate those seven routes, though the 777-300ER, A350-1000, or 787-11 could be used instead.
 
ltbewr
Posts: 15919
Joined: Thu Jan 29, 2004 1:24 pm

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 10:34 pm

I would suggest that the lack of sufficient diversion airports due to very cold environments (polar routes), over extended areas of water (mainly the Pacific Ocean), politics (Middle East, South Asia), high mountains (Himalayas, South America) and lack of quality facilities (Eastern Russia, certain areas of Africa), will all continue to require 4-engined large aircraft by some airlines and routes for the foreseeable future. Then you also have where a closest diversion airport may not be available due to weather (snow, ice, extreme cold, storms) or politics. In all those cases, which still can be factors on a relatively small number of routes, a 4 engined aircraft may be more appropriate and even economical as a 2 engined aircraft would have to take longer routes to keep within ETOPS.
 
parapente
Posts: 3061
Joined: Tue Mar 28, 2006 10:42 pm

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 11:16 pm

Part of the future is now. That is to say the A388 and the B748i.These 2 planes will continue to be sold.For the next,what ,10 years? However after that -if that is the question-no I cannot see a 4 engined plane -using todays engine technology.

However the engine/plane companies are looking at new technology. There was one recent example of a BWB with multiple small engines that helped (in theory) to smooth out wing turbulence (drag). I also wonder if the A350 will be the last new plane to use "conventional" engines. The 737 replacement will not use "standard" engines-that much we already do know. Whether it will be contrarotating fans or geared fans (or something else) we do not know. However these "new" engines may (or may not) have an optimal size ,which in turn would effect how many, a particular sized plane would have.
 
gsosbee
Posts: 365
Joined: Sun Jan 23, 2005 8:40 am

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 11:23 pm

Quoting Gbfra (Reply 50):
European and Asian carriers.

Agreed if you are talking about customer service.

However, you missed the whole point - Nationality has nothing to do with this discussion. This is pure economics - maximize revenue and minimize expenses.
 
BoomBoom
Posts: 2459
Joined: Fri Nov 04, 2005 2:26 am

RE: Whats The Future Hold For 4 Engines?

Tue Sep 04, 2007 11:58 pm

Quoting Gbfra (Reply 50):
Who are the most successful carriers across the Atlantic? Those who have 4-haulers or those who haven't? The fact that close-to-bankrupt US carriers can't afford to buy 4-haulers doesn't mean that there is no place for 4-haulers. Just ask BA, LH and AF. They can afford to buy them.

Are you suggesting if US carriers used 4-holers across the Atlantic they would be more successful financially?

Are you suggesting if US carriers were flush with cash they would buy 4-holers?

Faulty reasoning on both counts.

[Edited 2007-09-04 17:19:25]
 
zvezda
Posts: 8886
Joined: Sat Aug 28, 2004 8:48 pm

RE: Whats The Future Hold For 4 Engines?

Wed Sep 05, 2007 12:15 am

Quoting Parapente (Reply 59):
The 737 replacement will not use "standard" engines-that much we already do know. Whether it will be contrarotating fans or geared fans (or something else) we do not know.

It seems that PW will offer GTF engines for the 737RS and NSR but it seems that GE and RR will offer conventional HBR turbofans.

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