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Pressure On Boeing & Airbus To Improve 737&A320?  
User currently offlineKeesje From , joined Dec 1969, posts, RR:
Posted (8 years 9 months 3 weeks 17 hours ago) and read 5753 times:

I think if fuel prices stay as high as they are and environmental regulation around airport remain restrictive on noise, a interim higher BPR/lower noise versions of the V2500/CFM56 could become feasible before 2010.

Existing technological improvements that could be included:

- Noise-reducing chevrons on the trailing edge of the bypass duct, (fixed and variable)
- A one piece "jointless" inlet acoustic barrel (Trent900) with negatively scarfed air inlet
- A bigger fan, increasing BPR
- New 3D (composite/hollow titanium) S shaped fan blades and better lpc and hpt blades/vanes (as on newest GE/GP/RR engines).

The longer legs and an adjusted wingpylon construction of the a320 could allow for a higher BPR engine (10% additional radius?).

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Fan/BPR increases have been realized before on engine families such as the CFM56-5(C), CF6-80(E) and PW4000.

I´m not sure if the 737NG could be adjusted for a higher BPR engine (it already was after the JT8), but other improvements could be included.

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Giving the numbers of NB aircraft required, a projected 5-10 % lower sfc and stage 4 noise regulations can have operators (and thus Airbus and Boeing) becoming unwilling to wait for something completely new in another 10 years.

http://picavia.foxalpha.com/moyenformat/0304/003605.jpg
Negatively scarfed air inlet testing, December 2004

10 replies: All unread, jump to last
 
User currently offlineBoeingBus From United States of America, joined May 2004, 1596 posts, RR: 17
Reply 1, posted (8 years 9 months 3 weeks 16 hours ago) and read 5681 times:

At this point, the pressure is on the engine makers. simple as that! You can cut down the weight but you still need new engines to compliment that for 10 to 20% savings.

Airbus and Boeing won't start a new programme till engine manufacters come up with something new. Plus, you have Airbus working on the A350, A400 and A380 and Boeing finishing up the 772LR, 772LRF, 783, 788, and 789... the 747Adv is likely.... romor has it the 787-10 too.... so these two manufacters are going to be busy... busy... busy...

Just my 2 cents.



Airbus or Boeing - it's all good to me!
User currently offlineKeesje From , joined Dec 1969, posts, RR:
Reply 2, posted (8 years 9 months 2 weeks 6 days 19 hours ago) and read 5524 times:

Quoting BoeingBus (Reply 1):
Airbus and Boeing won't start a new programme till engine manufacters come up with something new.

& CFM & IAE won´t start a new program till Airframe manufacters come up with something new..

I think extreme oil prices, a booming industry & environmental regulations could motivate C or I to upgrade their offering in the 737/a320 segment.

Perhaps an opportunity for PW to regain their position in this huge market segment with a clean sheet design.

The V2500/CFM56 have been improved during the last 20-30 years but are a generation behind engines like the GEn-x, Trent 900/1700, GPp7200 etc.


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Another 10 years before a significant better NB engine, I don´t think so..

[Edited 2005-11-06 00:08:24]

User currently offlineDfwRevolution From United States of America, joined Jan 2010, 968 posts, RR: 51
Reply 3, posted (8 years 9 months 2 weeks 6 days 18 hours ago) and read 5488 times:

Quoting Keesje (Reply 2):
Another 10 years before a significant better NB engine, don´t think so..

I must disagree. With non-propulsion improvements available, will engine OEMs bother with a "PIP" or new engine in the near-term? On a cost basis, what could CFM or IAE offer that (1) wouldn't push the aircraft OEM into an all-new famly or (2) convince airlines to opperate a subfleet of the new engine?

I think a newer variant of the Aviation Partners winglet (or a debut of winglets on the A320 platform) might be more economical to newer 737NG/A320 engines. Winglets can be retrofitted to existing types whereas new engines implies greater complexity (more certification, maintenance subtypes, etc)


User currently offlinePlanemaker From Tuvalu, joined Aug 2003, 6144 posts, RR: 35
Reply 4, posted (8 years 9 months 2 weeks 6 days 18 hours ago) and read 5472 times:

Quoting Keesje (Thread starter):
I´m not sure if the 737NG could be adjusted for a higher BPR engine (it already was after the JT8), but other improvements could be included.

The 737NG cannot fit a higher BPR engine under its wing. In fact, at the Paris Airshow, CFM's president said that the next generation of narrow body engines will not even fit under the current A320's wing.

BTW, other than the nose gear leg being made 2" taller, there was no other adjustment made to the 737.



Nationalism is an infantile disease. It is the measles of mankind. - A. Einstein
User currently offlineBomber996 From United States of America, joined Aug 2005, 391 posts, RR: 0
Reply 5, posted (8 years 9 months 2 weeks 6 days 15 hours ago) and read 5350 times:

Quoting DfwRevolution (Reply 3):
I think a newer variant of the Aviation Partners winglet (or a debut of winglets on the A320 platform) might be more economical to newer 737NG/A320 engines. Winglets can be retrofitted to existing types whereas new engines implies greater complexity (more certification, maintenance subtypes, etc)

The A320 already has winglets. Even though they're called Wing tip fences, they do basically the same thing at APW winglets, but without the weight. Read this reply for a good explanation:

Air France Airbus A320 Without Winglets...?!

Should sum it up.

Peace  box 



AVIATION - A Vacation In Any Town, I Own Nothing
User currently offlineDfwRevolution From United States of America, joined Jan 2010, 968 posts, RR: 51
Reply 6, posted (8 years 9 months 2 weeks 4 days 19 hours ago) and read 5077 times:

Quoting Planemaker (Reply 4):
The 737NG cannot fit a higher BPR engine under its wing. In fact, at the Paris Airshow, CFM's president said that the next generation of narrow body engines will not even fit under the current A320's wing.

Planemaker! Long time to talk... good to here from you again.  wave 

Quoting Bomber996 (Reply 5):

The A320 already has winglets. Even though they're called Wing tip fences, they do basically the same thing at APW winglets, but without the weight. Read this reply for a good explanation:

I'm aware of the Airbus wing fence, I meant to imply an improved wing fence. I also doubt that the wing fence is so optimal that there is no other structure that could supercede the wing fence in efficency. There is certainly room for improvement in wingtip design given the advances in aerodynamics in the last ~2 decades.


User currently offline777236ER From , joined Dec 1969, posts, RR:
Reply 7, posted (8 years 9 months 2 weeks 4 days 18 hours ago) and read 5030 times:

Trent 900 8.7 - 8.5.

CFM56 5.1

Quoting Keesje (Thread starter):

- Noise-reducing chevrons on the trailing edge of the bypass duct, (fixed and variable)
- A one piece "jointless" inlet acoustic barrel (Trent900) with negatively scarfed air inlet
- A bigger fan, increasing BPR
- New 3D (composite/hollow titanium) S shaped fan blades and better lpc and hpt blades/vanes (as on newest GE/GP/RR engines).

All of which will do...not a lot!

Bear in mind the cost of redesigning a 5.1 bypass ratio CFM-56-7 to a 7-8 BPR version. The cost of design and certification far outweight any potential benefits. Small tweaks will be the order of the next decade, certainly until an A320/737 replacement appears.

The A320 and 737 aren't particularly noisy anyway. From an airline point of view, it's a lot easier to force pilots to fly more restrictive departure and arrivals routings and place more restrictions on the type of climb thrust selected and the use of reverse thrust than to go through the hassel of getting new and bizarre parts certified.

As for negatively scarfed inlets, RR have been doing research (as well as Airbus proper) on the design. The idea might be useful for the A320 and IAE (RR) equiped varients do suffer from distinctive (and annoying) buzz-saw noises from the LP fan. However, the negatively scarfed intakes disrupt the intake air, and even though the A320 and 737 operate at the begining of the transonic regime, shocks from the negatively scarfed intakes (apparently) have reduced engine efficiency in tests. Modified inlets and particularly increases BPR certainly come with weight and drag penalties. Increased BPR increases NOX emissions also. The choice in this area is between noise and emissions.

The better solution would be continue to tweak current designs (modified burners, active and passive acoustic linings, stricter adherance to FMC VNAV paths, new approaches, increasing overall pressure ratios graduly, using active stators, using the FMS to manage thrust levels and hence noise impact, a la A380). When new aircraft come along, then drastic changes can be made.

Certainly the big challenge for aircraft manufacturers right now is to figure out what the situation is regarding the use of oil. It's no good Boeing and Airbus developing A320/737 replacements now, when in a decade it becomes clear that XYZ technology is well on the way to banishing the use of crude oil.


User currently offlineAstuteman From United Kingdom, joined Jan 2005, 9997 posts, RR: 96
Reply 8, posted (8 years 9 months 2 weeks 4 days 10 hours ago) and read 4901 times:
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Back in Jan, there was an article in FI interviewing Baseler on this issue.

He was quite categoric that it's not worth tinkering with the 737 until "step-change" engines come along, and to complement that with a step-change frame. At that time he was quoted as saying "not before 2012 EIS.

I believe that last month he quoted "10 years away", i.e. 2015.

With 2000 frames backlogged, and these things flying off the shelves (for both A+B) so fast it makes your eyes water, I can't see there being massive pressure for an interim solution before those timescales.
(Isn't high fuel prices less of an issue for a short-haul narrowbody anyway?)

Certainly A+B have plenty on their plate at the moment, and I think that when the time comes, would want to have a "complete" solution to the narrowbody NG.

A


User currently offlineMolykote From United States of America, joined Aug 2005, 1340 posts, RR: 29
Reply 9, posted (8 years 9 months 2 weeks 4 days 9 hours ago) and read 4865 times:

Quoting Keesje (Thread starter):
Existing technological improvements that could be included:

- Noise-reducing chevrons on the trailing edge of the bypass duct, (fixed and variable)
- A one piece "jointless" inlet acoustic barrel (Trent900) with negatively scarfed air inlet
- A bigger fan, increasing BPR
- New 3D (composite/hollow titanium) S shaped fan blades and better lpc and hpt blades/vanes (as on newest GE/GP/RR engines).

Reminds me of the "Audi attitude". For the longest time Audi built cars with all the latest buzzword technology.... while being smoked by BMWs. Anyone remember the Audi 5000CS turbo quattro? - We had one and it couldn't hold a candle to it's competition - Too much technology and not enough practical value.

Without considering the design as a whole (and testing), it's unclear what if any advantages these technologies may have. I am sure that these technologies have been looked at as aircraft engine manufacturers are very agressive in these areas of noise/efficiency.

Some of the technologies you've mentioned are more applicable to larger engines - putting their use even farther off for the 737/A320 market. One example is the hollow/S-shaped fan blade. This doesn't make much aerodynamic and structural sense on smaller engines.



Speedtape - The asprin of aviation!
User currently offlineKeesje From , joined Dec 1969, posts, RR:
Reply 10, posted (8 years 9 months 2 weeks 4 days 9 hours ago) and read 4866 times:

Quoting 777236ER (Reply 7):
The better solution would be continue to tweak current designs (modified burners, active and passive acoustic linings, stricter adherance to FMC VNAV paths, new approaches, increasing overall pressure ratios graduly, using active stators, using the FMS to manage thrust levels and hence noise impact, a la A380). When new aircraft come along, then drastic changes can be made.

It seems to me none of the improvements you mention need a total new airframe. The A320 would be the one of the few aircraft designs that didn't get an upgrade half way down the road. The 737 got two..

Quoting Astuteman (Reply 8):
Certainly A+B have plenty on their plate at the moment,

Very true I think. A & B don't want to spend additional money on new designs at this moment & seem to disencourage the market accordingly. I still have the feeling a lot can be done without requiring a totally new design. CFM56 and V2500 are great engines & are improved (Tech56 like) but have their roots 20/30 years back..

However A350 as well as the different development programs at A & B show that a lot can be done.

Replacing the skin by AL-Li, replacing the tail by a composites variant, putting in bigger bins, windows, adding new flight control systems, screens, hud, wing extensions, winglets etc. come to mind.

Perhaps airline want to change their requirements as a result of current oil prices/environmental Hub restrictions too.

20% Less range & 5% lower cruising speed, but: 10% lower fuel & 25% less noise... some operators might be willing to go for it.. The other way around: if airlines should demand it, I doubt A&B would go for a totally new design.


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