When General Electric and Boeing collaborated to develop the GEnx engine earlier in the decade, the two aerospace companies always envisioned that the engine would first hang, and fly, under the wing of a 787 Dreamliner. Instead, the second GEnx variant, the -2B model which is rated at 66,500 lbs of thrust, was installed under the wing of the 747-8F late last week for the first time.
The -2B model has been in flight test since March 24th and has amassed more than 1,500 hours of ground tests and 100 hours of flight testing under the wing of GE's 747-100 test bed.
The -2B differs from the -1B engine with the inclusion of a conventional bleed air system, whereas the 787's systems are electrically driven.
As RC501, the first 747-8F, inches closer to flight test, Mohammad "Mo" Yahyavi, 747 vice president and general manager says that Boeing has identified 3,500 lbs or about 4/10 of 1% of the aircraft's 975,000 lb MTOW that will be removed for weight savings, according to a report by Aviation International News.
"At this point we are working with our suppliers. For example, one of our suppliers-[GE subsidiary] Middle River, which makes our thrust reversers for us-is coming up with some really good ideas for weight reduction and we are working with them to apply those.
One of those ideas involved switching from a steel to an aluminum ring. Asked about possible changes to materials used in other parts of the 747-8 to lighten the structure, Yahyavi confirmed "there are a few of those examples going on right now," as program engineers prepare for scheduled first flight of the freighter version during the fourth quarter.
In addition to receiving its four GEnx-2B engines, Boeing has also installed one of the aircraft's raked wingtip and will later install the second after leaving the factory to extend the 747 wingspan to 224 feet 7 inches, a growth of more than 13 feet over the -400 and -400F.Program sources tell FlightBlogger that RC501 could leave the factory for the paint hangar as early as the middle of the month, but suggest that the date is fluid and could slip to later in September.
Boeing says first flight is targeted for the fourth quarter of the year, with early indications that the company has set its sights on mid-November for the maiden sortie.
Photo Credit Boeing
on September 2, 2009 12:41 PM | Reply
Note that the left wing tip is not yet installed. It won't be put on until the airplane is moved to the second slant position due to clearance issues on the line.
on September 2, 2009 4:28 PM | Reply
That's one big bird! Can't wait to see her fly... at least we have another "first flight" to look forward to shortly while they sort out the 787!
Long live the 747!
-Rick
on September 2, 2009 4:44 PM | Reply
Uuh, since when are weight savings expressed as a percentage of MTOW?
More than anything else, you want to get empty weight down.
on September 2, 2009 5:50 PM | Reply
Fantastic! The weight story is music to my ears :)
on September 2, 2009 6:30 PM | Reply
Very nice, but is 3500lbs enough to bring in orders? That's the big question.
on September 2, 2009 8:43 PM | Reply
i love the bigger engines, it makes it more proportional
on September 3, 2009 12:58 AM | Reply
what is 4/10 of 1%,
why not simply 0.4% (0.36, to be more exact)?
on September 3, 2009 4:17 AM | Reply
It's because it sounds less. Spin spin spin, it makes the world go round.
on September 3, 2009 5:19 AM | Reply
Good news on the 748 programme. No talks of GEnx SFC improvements?
on September 3, 2009 6:16 AM | Reply
0.83% of OEW (Wikipedia figure for the freighter 421,200lb, Boeing does not seem to have a figure on the website). The other question is whether this reduction is necessary to meet contractual guarantees, or to meet internal targets. My totally uneducated guess is that it's for the latter.
on September 3, 2009 6:55 AM | Reply
It sure is shaping up to be a beauty. It will be very interesting to see if BA can meet its promised specs on the -8I. If all they have to do is shave 3500 lbs, they should be able to do it. And if they meet the specs, will they get more -8I orders if and when things pick up again? Lufthansa is sticking with their 20 firm/20 option deal. Is this because BA gave them an incredible deal in exchange for being launch customer, or because they really want a whole lot what BA is promising? That is, a super efficient 400-passenger-in-three-classes, very long hauler right in the middle between their 340-600s (my God, how can they stick with those?) and their coming 380s? Probably a little of both. I keep wondering why other airlines do not see what Lufthansa does?
on September 3, 2009 8:20 AM | Reply
@ Christopher Dye: "I keep wondering why other airlines do not see what Lufthansa does?"
This is the same thing I've been wondering about. But, seeing the plane coming together like this, should help a few more orders coming in.
on September 3, 2009 6:15 PM | Reply
(I'm the same Andrew from the last comment)
Well, a lot of carriers have shown interest in the aircraft, but weight problems have kept them from making the leap. Now that the 747-8 is on a succesful diet (hopefully Boeing can find some other ways to save weight), these carriers might finally jump.
on September 4, 2009 6:55 AM | Reply
Part of the weight issue is simply that the -8 has a more robust structure. The skin is thicker, some formerly aluminum pieces have been replaced with titanium, etc...
I'm doing my part by avoiding the use of washers where permissible per BAC specs. Extra washers=extra weight=possibly fewer orders=how long do I have a job?
regardless of weight, production is speeding up. With the first -8, a.k.a ln# 1420 almost out the door, we're busy drilling on ln# 1426.
She's a big beautiful bird. I can't wait to see her fly.