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GTF On A E Jets?  
User currently offlineNycbjr From United States of America, joined Aug 2007, 447 posts, RR: 0
Posted (5 years 2 months 1 week 4 days 15 hours ago) and read 3154 times:

Could PW strap a pair on a E Jets?

4 replies: All unread, jump to last
 
User currently offlineElpinDAB From United States of America, joined Apr 2005, 462 posts, RR: 4
Reply 1, posted (5 years 2 months 1 week 4 days 14 hours ago) and read 3138 times:

Sure, but they'd have to re-design the landing gear!

Okay, I'm not a mechanic or engineer, but wouldn't they have to extend the gear? The E190/5 engine nacelles are already curved to accomate the GE's that they have, which are much smaller in diameter than the GE's? That would cause a re-design, which would be fully managable for a company that has seen so many orders.

But, Bombardier's C-Series seems like the most viable opportunity for the PW GTF. It's a much better aircraft design in my opinion. The Ejets are just a regional jet, and, while roomy inside and nice to look at, they seem cheaply built (no offense to the Embraer enthusiasts), while the C-Series would be an entirely new mainline jet built to optimize performance in places where MD-80 style aircraft (and the 736/A318) have left off. ( And yes, I've ridden on all of the competitive types, though never flown them.) They would offer an increase in fuel performance and comfort. If Bombardier could beat Boeing and Airbus to this market, then they could succeed, and they seem to be on track, despite the news of few orders. (BUT, ISN"T LUFTHANSA THE ONLY MAJOR AIRLINE IN THE HISTORY OF THE INDUSTRY TO GENERATE A GROSS PROFIT SINCE IT'S CREATION???? Correct me if I'm wrong on this, as it's just what I've been told in my studies of aviation.) I really hope that the C-Series prevails against the Ejets because it's just a superior design for the mission! The E-jets are regional jets at heart, and could be made into hot-rods, but it just wouldn't be right. The C-Series would be a true economical replacement to the aging fleet of small narrowbodies. They would be perfect for every mission besides a transcon-US flight with abnormally strong jetstream winds, and would offer superior performance on those routes. (Although, the ER versions would be able to combat those conditions.)

The C-Series just seems like a perfect replacement for sooo many aging aircraft types, and it disappoints me to see so many E-Jet fanatics who thing that it's the answer for an MD-80 replacement. McDonnell Douglas left a huge gap to fill when they left for Boeing! The A318 and 737-600 just seem so over-engineered, that I know huge savings could be made with a new type. The A319/20's are great aircraft, but Airbus doesn't want to replace them until 2020. Too long.

Come on, Bombardier, step up to the plate!!! Create the plane that we know will be a savior! Plenty of airlines could use this new technology. And, the rate of technological expansion is growing exponentially, so the C-Series will probably be about as advanced as the the E-Jets are compared to the MD-80 series. Go Moore's Law!!! In the age of computer-design, you can't dispute that.

Care to comment?


(Sorry, I'm a huge C-Series advocate, and I can't help it.)


User currently offlineLightsaber From United States of America, joined Jan 2005, 12421 posts, RR: 100
Reply 2, posted (5 years 2 months 3 days 23 hours ago) and read 2849 times:
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Quoting ElpinDAB (Reply 1):
Okay, I'm not a mechanic or engineer, but wouldn't they have to extend the gear?

To acheive peak efficiency?  yes 

To put a much more efficient GTF on the E-jets?  no 

Here are the features to reduce fuel burn the CF-34 lacks:
1. Contra rotation (that is worth a ~3% reduction in fuel burn).
2. The GTF gearbox (6% cut in fuel burn for the same fan diameter, ~10% if new gear were installed. I would stick with the current gear)
3. Dual row High pressure turbine with matching high pressure compressor stages. This is worth about 3% in this size of an engine. (I normally quote a 4% reduction in fuel burn, but please recall that smaller engines with smaller diameter compressors/turbines have proportionately more tip losses and thus not all of the benefit can be captured.)

There is also other new technology looking to go forward in the C-series. For example, integrated blade rotor compressors (IBR) (see the GEnX for the 748, low pressure compressor). This will cut weight and fuel burn too!  hyper  Oh, in a LPC, only about 1/2% fuel burn. For the High pressure compressor (HPC), more fuel burn could be cut, but *none* of the engine makers are ready to make the last stages of the HPC IBR. So where the greatest efficiency could be gained, they will still implement the 'fir tree' slotted compressor blades. Why? The precision of the friction welding isn't quite precise enough... today. Every engine manufacturer is working on it.

so while fuel burn cuts are not quite additive, the E-jets could cut their fuel burn about 14% with a new GTF.  spin  It would help the economics. But it would not, on its own, provide coast to coast range.  Sad

Quoting ElpinDAB (Reply 1):
so the C-Series will probably be about as advanced as the the E-Jets are compared to the MD-80 series.

No launch customer. I know of quite a few engineers excited about the C-series. But good luck launching a new plane in this economic environment.  Sad

Sigh... which isn't helping the GTF's.  Sad

Lightsaber



I've posted how many times?!?
User currently offlinePPVRA From Brazil, joined Nov 2004, 8875 posts, RR: 40
Reply 3, posted (5 years 2 months 3 days 18 hours ago) and read 2808 times:



Quoting ElpinDAB (Reply 1):
And, the rate of technological expansion is growing exponentially, so the C-Series will probably be about as advanced as the the E-Jets are compared to the MD-80 series. Go Moore's Law!!! In the age of computer-design, you can't dispute that.

Embraer has said they don't plan on building a product to go after the 737/320 for now because current technology just isn't better enough over that what is already available with the 737/320 offerings. On that ground I refute your statement that what the C-series would offer would be significantly improved over the E-jets or the 737/320, aside perhaps from the engines, which can be placed on the other jets as well, contracts permitting.

Boeing's and Airbus' decision to delay a replacement could be because of weak markets, but could be just as well because of future technological expectations.



"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineElpinDAB From United States of America, joined Apr 2005, 462 posts, RR: 4
Reply 4, posted (5 years 1 month 4 weeks 17 hours ago) and read 2561 times:



Quoting PPVRA (Reply 3):

Embraer has said they don't plan on building a product to go after the 737/320 for now because current technology just isn't better enough over that what is already available with the 737/320 offerings.



Quoting PPVRA (Reply 3):
Boeing's and Airbus' decision to delay a replacement could be because of weak markets, but could be just as well because of future technological expectations.

Very good points that I hadn't considered enough. Boeing and Airbus are wise to not launch a new type in today's market. However, given the ups and downs of the economy, and the length of time that is required to design a new jetliner, I think that they should start designing now, otherwise they will be pressed for time to develop their mainstream narrowbody replacements, and they will fall short of expectations. That said, I think that it's a great time for Bombardier to launch their rival, even with the slow economy, because its first deliveries would occur about the the time the economy will begin to peak again, unless the world politicians screw everything up, which isn't fully out of the question. I guess I'm biased towards viewing the world economy from my US perspective, but I don't see the US economic stimulus package benefiting anybody in the long-term. You can't create money without a concrete foundation, but both the Dems and Republicans alike here in the US seem to think that this practice will sustain a world economy. It might appease the TV watching public until the next election, but it definitely won't help a single soul in the future. But, I still think that the CSeries on its current schedule, is set to enter into service about the time the airlines will be able to afford it with an economic upswing and a mass retirement of pilots due to the age 65 rule.

As for the technology, keep in mind that aviation is a very conservative industry that evolves much more slowly than what should be expected from other industries. I'm still (pleasantly) surprised that the suborbital space programs are still thriving. But, the CSeries seems to be a package that offers 787 advances in technology for narrowbody aircraft. Small trends are nice, in the relative scheme of recent aircraft advancements. Unfortunately, it seems that we will be limited to Mach .80-optimized airliners until the next generation is ready to retire, unless there is a radical revolution.

With that said, I'm definitely not trying to bash the EJets, because they are solid aircraft that serve their purpose very well. They are regional jets that offer superior comfort for passengers, at the expense of being slightly more thirsty for fuel than, say, the CRJ-900.
They do offer much better economy than the Avro's or Fokkers though. And, the 190's and 195's can more efficiently serve many routes that the -318's and 736's currently serve.

I guess to close with my comments to you, I think that the CSeries would be a perfect replacement for many aging mainline aircraft. The GTF is almost a 21st century replacement for the JT-8D powered aircraft, as well as the over-engineered narrowbodies that have replaced the said aircraft so far. This cuts into the lower end of Airbus and Boeing narrowbodies, although the market has its own niche that is due for a brand new, optimized product. (eg, NW (DL) DC-9 routes.) The EJets are regional jets at heart, which was their design purpose. Mounting GTF's on them would essentially be the equivalent of mounting GTF's onto the CRJ 900/1000's. Sure, they would see some performance gains, (and become fighter performing regional jets) but the GTF seems to be a PERFECT match for an aircraft such as the DC-9-50/MD-80/87, and to a lesser extent, the Airbus A318/19, and Boeing 736/7. (Although the A319 and 737-700 are both impressive aircraft that offer unmatched performance.)

BTW, I really can't believe that the E190/5 use the same basic engine as the CR2's! GE must really know how to use that engine, but, those jets might be more efficient with another type of jet...just my speculation on it, don't know the facts. The E195 really seems to be the largest feasible stretch of the Ejet series with the given wing...It would surely benefit from a larger wing. (And for a separate thread in the future, how does the -190 do so well with its configuration!? 2200nm on a CRJ engine with 90 pax and wing loading similar to an MD-80! Must be a great wing! Props to the Embraer folks...Your T-props don't take ice worth a damn, and can't heat the cabin in the winter up north until short final at the destination. The ERJ's always take weight restrictions...But the ERJ's seem solid for their current mission. I say, don't stretch it. They're great how they are. GTF's are for the majors.

Quoting Lightsaber (Reply 2):
peak efficiency

Thanks for all the great info, LightSaber! This is very interesting to read, especially from an engineer's point of view, knowing all of the facts behind the design specs. I'm glad to hear that most of you engineers support the CSeries also. I really do hope that it succeeds, because I think that if they keep the program going through the current economic hardships, then they will be golden with new customers when the need arises. Being at the right place at the right time takes a little risk.

Mark my word, Bombardier, if you continue the CSeries program and deliver a plane that meets your current specs, then you will have a winner! And if you don't somebody else will, and they will be exactly under your specs. Go for it Bombardier, or you will miss out greatly upon great opportunities!


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