keesje From , joined Dec 1969, posts, RR: Posted (3 years 10 months 1 week 2 days 13 hours ago) and read 25459 times:
Flightglobal reports Boeing is looking at options to fit a bigger fan.
An Airbus NB engine upgrade seems almost sure, Boeing has to follow. I guess it won't be a shoe in. Wonder if they go GTF and/or LeapX.
. To provide additional clearance under the wing to accommodate a larger engine nacelle, Boeing is examining the feasibility of raising the 737's nose landing gear, say industry sources. According to those familiar with the plan, an extension of the nose landing gear of 15cm (6in) would yield an estimated 5cm of additional diameter in the fan.
I suppose that depends whether they have an exclusivity agreement with CFM for the 737. If so, they have no other choice than LEAP-X. However, the article does seem to indicate that an IAE or PW engine is possible. Maybe they will go the Airbus route (right now with the CFM and IAE option) and offer a choice of engines.
keesje From , joined Dec 1969, posts, RR: Reply 2, posted (3 years 10 months 1 week 2 days 12 hours ago) and read 25190 times:
I think it will be interesting to know what bypass ratio Airbus is aiming at. 25 years ago they were in a starter position contrary to a market leader now. Changes their negotiation power towards the engine manufacterers. An open rotor seems impossible, but what's next best?
I would not be surprized if they go for the highest possible BPR, maybe giving in a few percent on weight and speed, but gaining a few percent additional sfc.
I would not be surprised if this ends up in Boeing being driven to launch something entirely new, earlier then they hoped. The 767-400ERX & 747-8i come to mind..
FlyDreamliner From United States of America, joined Jan 2006, 2759 posts, RR: 15 Reply 5, posted (3 years 10 months 1 week 2 days 11 hours ago) and read 24904 times:
Quoting Aloha717200 (Reply 3): How much engineering difficulty would it be to modify the main gear legs as well and increase the overall height of the 737?
I wonder about this too. I think it all comes down to how much of a change in 737 Boeing wants to make. Moving to a 757-style landing gear (albeit smaller, lighter, conventional main gear bogies and probably shorter, as 757 rides very high) seems in all ways possible, but it necessitates a large number of other changes, also.
Another issue for Boeing is that many of its customers, like WN (though I'm sure many others) specifically prefer the 737 because of its low ground clearance. They believe it allows faster turns as rampers can perform many more functions without ladders/lifts than on taller aircraft and likewise allows faster mx to be performed in some cases. For this reason, they might be looking to increase the height by the smallest possible amount.
Engine choice will be big here, also. The PW GTF is going to have a larger diameter, for sure. I have not seen any fan diameter specs for Leap, but I assume CFM has 737 in mind to some degree. IAE building an engine to compete with PW's GTF seems odd to me... as PW is a major partner in IAE, so I'm interested to see how that plays out.
I think when all is said and done, they will need more than a small lift in height of the front gear. Obviously increasing the main gear, while more "change-intensive" will yield the most engine ground clearance.
"Let the world change you, and you can change the world"
parapente From United Kingdom, joined Mar 2006, 1401 posts, RR: 10 Reply 6, posted (3 years 10 months 1 week 2 days 11 hours ago) and read 24872 times:
One thing is certain from the absolute flood of and increasing frequency of press releases from both Boeing and Airbus is that re engining is now a given.
Airbus can and will and it appears that with a small modification so can Boeing.Neither wants (or can afford) totally the vast cost and resource requirements needed to go for a clean sheet design.And even if they could (which they can't) the "game changing" technology what everyone is looking at (open rotor) is not nearly mature enough.
This too has been openly stated.So it's 2014 for a re engine and 2024 for the new aircraft.That at least is what they are both saying.It seems to make perfect sense so why not believe them? I for one do.
oyKIE From Norway, joined Jan 2006, 2647 posts, RR: 4 Reply 8, posted (3 years 10 months 1 week 2 days 9 hours ago) and read 24148 times:
If Boeing raises the nose, the article states that it will make a tight space for avionics. Perhaps Boeing will completely redesign the whole noese section and FBW? That would increase the aerodynamics as better the entrance on for faster boarding and FBW would make the plane a bit lighter.
Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
Pratt & Whitney's PW1000G can be installed on the 737NG and will achieve a double-digit fuel burn improvement, according to Senior VP-Sales Bob Keady. Responding to a question from ATWOnline here, he said preliminary studies have been completed and Boeing has "some very smart engineers" and would not need to modify the main undercarriage."
pnwtraveler From Canada, joined Jun 2007, 2145 posts, RR: 12 Reply 10, posted (3 years 10 months 1 week 2 days 8 hours ago) and read 23917 times:
We have kneeling buses to help passengers get off and on, we have pimped out cars that raise and lower, how much more would it take to have kneeling planes to allow extra room for landing but lowered for easy ground worker access for WN and other quick turn operators. Maybe Fosse mags would also set the aircraft off nicely with a whole "Overhaul" package. For those not from North American, "Overhaulin" is a TV program where someones beat up older car is "stolen" with the help of a family member or friend, and is stripped down and rebuilt into a fine car by Chip Foose and his team. and the owner is surprized with the shiney result.
While I am joking, I imagine the stresses involved with landing would make some kind of suspension to raise and lower the aircraft unlikely.
And if you get to the point of making too many modifications to the 737, such carbon fibre wings or other parts a la 787, you are no longer simply looking at a simple re-engine exercise you are encroaching the next replacement aircraft. This will be interesting to see how it works out.
keesje From , joined Dec 1969, posts, RR: Reply 12, posted (3 years 10 months 1 week 2 days 8 hours ago) and read 23756 times:
Quoting DLPMMM (Reply 9): I think you should maybe tell this to P+W.
Fair use from ...... double-digit fuel burn improvement, according to Senior VP-Sales Bob Keady.
I think using your own eyes & common sense without copying what Marketing & Sales people told us proved a fine strategy in recent years. The PW GTF was about to become an A320 option, 12 years ago.. That's why Airbus wants big brother RR to put their stamp on the GTF too.
Quoting BMI727 (Reply 11): It is possible, but not a small matter by any means. There are some out there who would contend that once you design the landing gear, you have effectively designed the whole aircraft.
New wing, new engines new landing gear, what about a composites tail and 757 nose section, it fits
Stitch From United States of America, joined Jul 2005, 28520 posts, RR: 84 Reply 13, posted (3 years 10 months 1 week 2 days 8 hours ago) and read 23586 times:
LEAP-X is a given on the 737 platform.
As to the GTF, I trust Pratt to at least have a good idea of their own product, if nothing else. Bob Saia, P&W's VP of Next Generation Product Family (so an engineer, not a marketer) has stated in a very interesting podcast last May that a 737/A320 class aircraft needs a GTF with an 80" fan and a 96" nacelle. This would be about 17" wider than the current maximum fan diameter noted in the FlightGlobal article. He also stated that because a GTF can be mounted higher and farther forward on the wing, this would improve it's packaging on a 737 class airframe and help with the nacelle clearance issue. Work will need to be done, but as Mr. Keady noted, there are smart engineers out there working on the issue.
And when "market leadership" is measured in a handful of percent, I'm not sure that means the supplier in the Number 2 position is necessarily in a position of imminent demise. Let us try to not forget that Boeing reached the 5000 orders mark for the 737NG in exactly fifteen years (11/93 to 11/08). During the first fifteen years of the A320 program, even as it held a clear advantage over the 737 Classic Family for the first decade, secured a bit more than half that many orders (2551).
DLPMMM From United States of America, joined Apr 2005, 3566 posts, RR: 10 Reply 14, posted (3 years 10 months 1 week 2 days 7 hours ago) and read 23506 times:
Quoting keesje (Reply 12): I think using your own eyes & common sense without copying what Marketing & Sales people told us proved a fine strategy in recent years. The PW GTF was about to become an A320 option, 12 years ago.. That's why Airbus wants big brother RR to put their stamp on the GTF too.
I'm sorry, but I don't understand your comment. I realize that english is not your first language.
My link and direct quote published today from P+W at the Singapore Airshow stating that the preliminary studies have been made by P+W and Boeing and the results were that the main undercarriage would not need to be modified. That looks to me to be a straight forward statement from an authoritative source.
You seem to disagree with this statement.
Do you have a more authoritative or up to date source?
web500sjc From United States of America, joined Sep 2009, 631 posts, RR: 0 Reply 17, posted (3 years 10 months 1 week 2 days 7 hours ago) and read 22556 times:
How about having the struts on the MLG extend in and out when coming in or out to raise the aircraft. When the pilot rasies the gear, the plane will pull in the cushion part of the strut, allowing a theoretically longer gear in the same place.
TomB From United States of America, joined Nov 2006, 78 posts, RR: 0 Reply 18, posted (3 years 10 months 1 week 2 days 7 hours ago) and read 22361 times:
If the reports are correct that the CFM LEAP-X engines will weigh 1,000 to 1,200 pounds less than the current CFM 56 engines, then that will mean a 2,000 to 2,400 pound weight reduction in front of the center of lift. To rebalance the weight on the revised aircraft, I think Boeing has an opportunity to completely redesign the nose section of the aircraft. The major goals of the redesign will be to 1) add one more row of seating to the aircraft increasing seating capacity approximately 4%, 2) incorporate a longer nose gear to give the new engines more clearance, 3) improve the aerodynamics of the nose section, 4) perhaps incorporate a larger door to speed loading and unloading and 5) change the appearance of the aircraft so it is readily recognized as an upgraded 737.
The new nose section could either built of aluminum or composites. Spirit has the capability to do either. The new nose section would be amortized over several thousands airplanes over a 10+ year production run so it would be an affordable modification.
The resulting revised 737 would have 1) a 16% reduction in fuel burn, 2) a 4% increase in seating capacity without an increase in the aircraft crew and 3) perhaps a 1% or 2% improvement in aerodynamics due to the new nose section. The revised 737 should thus have a solid 20% improvement in seat mile costs over the 737NG.
Aesma From France, joined Nov 2009, 5705 posts, RR: 9 Reply 21, posted (3 years 10 months 1 week 2 days 6 hours ago) and read 21770 times:
Quoting oyKIE (Reply 8): If Boeing raises the nose, the article states that it will make a tight space for avionics. Perhaps Boeing will completely redesign the whole noese section and FBW? That would increase the aerodynamics as better the entrance on for faster boarding and FBW would make the plane a bit lighter.
That's exactly the kind of thing they wouldn't want to do. That's the sort of parts the 737 still has from the classic classic.
Quoting pnwtraveler (Reply 10): While I am joking, I imagine the stresses involved with landing would make some kind of suspension to raise and lower the aircraft unlikely.
Well, military transport planes do it fine.
New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
Yes of course wasn't thinking of the C5A and others than lower to ease off and on of cargo so you are correct. I wonder though about the expense and the frequency of repairs to that system. Military aren't always looking for cost effective solutions as much as getting the job done.
25 Stitch: It appears that for most 737 missions, the blended wingtips work better. Raked wingtips were added to the P-8 program in part because they do not blo
26 SolarFlyer22: It could and the soviets were big fans (no pun intended) of this method because it means 1) The engines will ingest less debris being above the wing
27 trex8: wouldn't it have to be double sized to make any practical difference?
28 N328KF: Add to that the fact that the DoD doesn't exactly have to worry about gate space.
29 BMI727: Also, if the engine is placed just on top of the wing and not on a strut, you can realize gains from the Coanda effect. By the way, the Soviets weren
30 Marcus: Not to mention the numbers of daily cycles on a civilian aircraft vs. a military one.
31 Marcus: Would a double size door make sense if you still have the same width aisle inside the aircraft?
32 XT6Wagon: WN thinks so, one of thier items on the want list is a larger entryway. Right now the traffic jam happens just inside the door where people need to t
33 Revelation: Yep, but those knees don't have to take the pounding that an aircraft landing takes. Indeed it was the B-47, which has most of the features of all mo
34 DH106: Concorde used a system where the main gear struts shorten slightly as part of the retraction sequence (not the oleos compressing but a mechanical sho
35 planemaker: That is on the propulsion side. The same goes for the airframe and systems side... they aren't ready for prime time! C'mon, Keesje, you DO know bette
36 N685FE: I don't see that doubling the size of the door would add a lot of speed to getting ppl to sit down. I think it would speed up the time to fill the is
37 727forever: The J-41 also had the nose gear hydraulically compress for retraction. This allowed BAe to use the same sized nose and gear well on the J-41 as on th
38 Bureaucromancer: Somehow I don't see them doing anything that requires replacing the nose or doing any significant work on the wing with Y1 in the works... Most likely
39 clydenairways: If Boeing are going to redesign the nose section then they might as well make it in the 787 style rather than the 757. The 757 nose section is more ae
40 N685FE: IF they are going to do this much work to the current design, they might as well save their pennies and hold out for a whole new design. Start with a
41 keesje: Yes, some smarter wings, tail adjustments, some quick win composites, copy in some 787 style systems & cockpit and you have an easy fix / great v
42 exFWAOONW: Nah, the pax would be lined up in the jetway while they try to make room for the door to swing open.
43 FLY2HMO: All that hassle for just 5cm? Not worth it IMO. If anything lifting the mains would make more room, of course it would require a major redesign and is
44 WNCrew: Was that meant to be tongue and check cause that looks like a WHOLE NEW airframe!...I really like it though, looks sharp!