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Originally Posted by misd-agin
(Post 10657412)
That comment has also been stated in articles about the next narrow body design. For longer range flights the lighter weight, but more expensive construction method, is worth it. For shorter flights the cost/analysis is harder to justify.
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Originally Posted by tdracer
(Post 10661230)
I don't recall that weight was as big a concern during the 767 development relative to the 757, although I couldn't say why that was the case. I do know that when I was working the 757 (late 1990's) we worked several changes that resulted in heavier parts but with much lower manufacturing costs. It's probably worth noting that neither the 757 or 767 were envisioned to morph into the longer range aircraft they eventually became - in the case of the 767 it went from 320,000 lbs at EIS to over 400k less than ten years later (helped considerably by the upgraded engines that came along in 1988).
It's not really fair to compare the 767 with the A330 - the A330 came along over 10 years after the 767 and hence the more direct 767 comparisons would be with the A310 and A300-600. I flew the A300-600. The 767-300 was more capable. Guys used to say "but the A300 uses less runway." Looking at the books and the 767-300 could lift more weight off of the same runway and cruise faster, and farther, on the same gas. The A300 did out climb it because they didn't use CLB 1 or CLB 2 to baby the engines. I don't know what the 757 was originally certified at but ours were originally limited to 220,000 lbs takeoff weight. Then it went to 240,000 lbs, then 250,000 (?), then 255,500 lbs. USAF guy said they flew there's at 270K (280K???). As the RR engines faded their max thrust was derated from 44,100 to 43,700. A seat of the pants comparison - a STD/FLEX power takeoff with RR engines producing 44,100 felt similar to a max power takeoff with the 37,500 P&W engines. It wasn't uncommon, especially on your first flights with the 37.500 thrust engines, to think the engines weren't producing full thrust. I've also experienced that after months of flying into SFO with a 767-300 only to have it replaced with a 767-200 on one flight. |
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Originally Posted by misd-agin
(Post 10661654)
The 320,000 lbs a/c was also the 767-200. The 400K+ was the 767-300 with 61,500 lbs of thrust vs the 48,000 lbs available on the 767-200. Our 767-200's were originally limited to 310,000 lbs (?), then 320,000, then 351,000 lbs, all with the same thrust engines.
I flew the A300-600. The 767-300 was more capable. Guys used to say "but the A300 uses less runway." Looking at the books and the 767-300 could lift more weight off of the same runway and cruise faster, and farther, on the same gas. The A300 did out climb it because they didn't use CLB 1 or CLB 2 to baby the engines. I don't know what the 757 was originally certified at but ours were originally limited to 220,000 lbs takeoff weight. Then it went to 240,000 lbs, then 250,000 (?), then 255,500 lbs. USAF guy said they flew there's at 270K (280K???). As the RR engines faded their max thrust was derated from 44,100 to 43,700. A seat of the pants comparison - a STD/FLEX power takeoff with RR engines producing 44,100 felt similar to a max power takeoff with the 37,500 P&W engines. It wasn't uncommon, especially on your first flights with the 37.500 thrust engines, to think the engines weren't producing full thrust. I've also experienced that after months of flying into SFO with a 767-300 only to have it replaced with a 767-200 on one flight. |
Originally Posted by tdracer
(Post 10662277)
The initial 767 engines (JT9D-7R4 and CF6-80A) topped out at about about 50k thrust, even on the 767-300. The new engines we certified in the 1988-89 time frame (PW4000, CF6-80C2, and RB211-524G/H) went from about 52k to 62k (they offered a 50k rating on the PW4000 but no one ever bought it). The highest rating they ever delivered for the 767-200 was 60k, while 62k was available for the -300 (the 767-2C/KC-46 uses the 62k PW4000 with an available bump). IIRC the max available MTOW for the 767-200 was 380,000 lbs, but I wouldn't swear to it (the 767-2C/KC-46 is 407,000 lbs.)
Obviously your expertise goes back farther and across more carriers. I do know with the later engines on the 767-200 (60K+?) they had higher than 351K max takeoff. I think a buddy flying them said it was around 380K so our memories are similar. |
Originally Posted by unobtanium
(Post 10662268)
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Originally Posted by misd-agin
(Post 10662833)
That has to be a hoot. Flying a light 747-400 with 4x 105,000 (?) lbs thrust engines.
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One Biggee in original image
Originally Posted by tdracer
(Post 10663006)
That's photoshop. Pretty good photoshop, but definitely photoshop.
For example this page contains a copy. I don't know whether the site software will permit my link to survive, but in preview it worked. I promise the base image is the same--the foreground vegetation is pretty distinctive. |
Originally Posted by tdracer
(Post 10663006)
That's photoshop. Pretty good photoshop, but definitely photoshop.
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Originally Posted by flyfan
(Post 10655748)
In my oppinion
*737 absolutely & urgently needs replacement, basically a shrunken, single aisle, up to date 787. Airbus is delivering A32x at maximum rate, so they can't really take advantage of the MAX grounding for the next few years. Use that time to develop this plane and don't waste time with the MAX. Even if it would probably be a safe plane once it is in the air again, the public impact is enormous, and it would be better to start from scratch. After 53 years it's definitely not too late. In the meanwhile open up the NG line again (well, it's kind of active anyway with the Poseidon) and keep customers. *757 / 767 market can be taken over by the 787 range. *777 is for the moment more or less fine as it is, especially with the 777X. Anything bigger? Not needed - see the A380, which is already being replaced. Supersonic? As an aviation fanatic it would be nice to see, but as long as there's a sonic boom...absolute waste of money to develop - not even talking about the fuel efficiency of the engines. If it was wise to buy Embraer's E-Jets program...I don't know. But it opens the commuter jet market for Boeing, just like the C-Series did for Airbus. But...I'm not an aviation analyst, so probaly I'm not taking into account everything which is going on behind the scenes. |
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