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Why No A330 With A340 Range?  
User currently offlineUal747 From , joined Dec 1969, posts, RR:
Posted (14 years 5 months 1 week 6 days 23 hours ago) and read 2569 times:

It would make sense for airbus to develop an A330 with the range of the A340. In fact, why do they even need the A340 at all? If the right engines could be developed, it would seem that it would be more effecient and cheaper to fly and maintain. Why does airbus continue pushing the A340 when they could do the exact same with the A330? If they could extend the range of the A330, then it might be more of a contender against the 777.

26 replies: All unread, showing first 25:
 
User currently offlineD L X From United States of America, joined May 1999, 11325 posts, RR: 52
Reply 1, posted (14 years 5 months 1 week 6 days 21 hours ago) and read 2153 times:

There are a lot of technical reasons why the 330 can't just be extended for greater range, or more accurately why the 340 having the same wing gets better range than the 330. I actually don't fully understand the reasons, but I'll try.

The 330 has two giant engines that together are heavier than the 340's 4 smaller engines total. This is important because engine weight affects range. Also, having 4 engines spread out along the wings helps with the wing structure so less weight is used in support, and more space is available for fuel. That seems rather counter intuitive, but think about how much wings want to bend upward due to their lift, and supporting something heavy (the fuselage) in the middle of the span. Twins have to have their engines close to the fuselage for safety reasons so there is even more tendancy for the wings to bend. That has to be counteracted by adding extra structural support inside the wing to make it bend less. Having four engines relieves that requirement some because the engines themselves prevent the wing from bending as much. Thus less extra support, and that space can be used for more fuel, and hence longer range.

The only way that the 330 will see 777x range is if two things happen: the wing would have to be completely redesigned for the role (as in different from the 340 wing) and larger engines (and landing gear) would have to be added as well to push the extra fuel weight. That is quite a daunting task, but I do see Airbus doing it in the future, especially if the 3XX actually happens. (In that case, the 340 may die off.)



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User currently offlineCPDC10-30 From United Kingdom, joined Feb 2000, 4781 posts, RR: 23
Reply 2, posted (14 years 5 months 1 week 6 days 21 hours ago) and read 2134 times:

Don't forget that of course the A340 is exempt from ETOPS rules by having four engines. They can fly a shorter route - if one is feasible. I heard on this board earlier that Canada and Russia are investigating cooperating on upgrading air navigation services in the far north. That way, flights from North America to Asia would be able to fly over the north pole, which is a shorter route. The A330 and 777 have to stay within 180 minutes of an alternate, while the A340 (also MD-11 and 747-400) would not be limited by these rules.

Anyways..four engines has a "classic" look like a 707 or DC-8.


User currently offlineCstarU From , joined Dec 1969, posts, RR:
Reply 3, posted (14 years 5 months 1 week 6 days 20 hours ago) and read 2132 times:

Another reason would be marketing---If the A330 had the range of the A340, then it would compete with the latter rather than complementing it. Also, Airbus' philosophy that four engines are better suited in the long range role (5,000nm+), mainly ETOPS.

User currently offlinePilot21 From Ireland, joined Oct 1999, 1384 posts, RR: 2
Reply 4, posted (14 years 5 months 1 week 6 days 6 hours ago) and read 2095 times:

As most of the reasons have been mentioned, I'll keep this short, bascially it comes down to wing design. When airbus were investigating the A330/A340 design concept, the found that due to the structural bending of the wings with the different engines on them them, a four engined airliner was better suited to flights of over 5,000 miles, and thus a two engined was better suited to a flight of less then 5000 miles. Thus the main reason is aerodynamics.


Aircraft I've flown: A300/A310/A320/A321/A330/A340/B727/B732/B733/B734/B735/B738/B741/B742/B744/DC10/MD80/IL62/Bae146/AR
User currently offlineJohn From United States of America, joined Sep 1999, 1374 posts, RR: 5
Reply 5, posted (14 years 5 months 1 week 6 days 5 hours ago) and read 2084 times:

The A330's different engine types ARE NOT AS HUGE and powerful as the 777's powerplants. Now those engines are HUGE! They dwarf the 330's by comparison.

User currently offlineD L X From United States of America, joined May 1999, 11325 posts, RR: 52
Reply 6, posted (14 years 5 months 1 week 6 days 2 hours ago) and read 2062 times:

I would also add that Airbus now admits that the 5000nm rule they devised when creating the 330 and 340 is obsolete in that twins are quie capable beyond 5000nm. But that's because there are larger engines that were not available when the 330 and 340 were designed.


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User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 7, posted (14 years 5 months 1 week 6 days 2 hours ago) and read 2066 times:
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D L X writes that the A330 has a heavier wing structure than the A340. This is not the case, the A330/340 airframe structure, less the engine pylon attachments is identical.

User currently offlineD L X From United States of America, joined May 1999, 11325 posts, RR: 52
Reply 8, posted (14 years 5 months 1 week 6 days 1 hour ago) and read 2061 times:

I may be wrong, but would you care to explain why supposedly identical wings don't have the same fuel capacity?

Since you work on these things, you may be able to clarify. I was under the assumption that the 340/330 wing is incredibly similar but the 330 wing has a couple of structural units to help the wing bend found on all twins where the 340 has a larger fuel cell there.



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User currently offlineJohn From United States of America, joined Sep 1999, 1374 posts, RR: 5
Reply 9, posted (14 years 5 months 1 week 5 days 23 hours ago) and read 2061 times:

This shorter fuselage version does have significantly longer range. US Airways is considering it, and may switch some options to the -200 variant. The A340-500/600 is also being evaluated for future use, should US Airways decide to venture out over the vast Pacific, which, I believe, in the near future, is probably inevitable. There's money to be made and lot's of routes to fly that remain uncharted, for the time being, anyway.

User currently offlineTimz From United States of America, joined Sep 1999, 6835 posts, RR: 6
Reply 10, posted (14 years 5 months 1 week 5 days 18 hours ago) and read 2035 times:

So far the flying public has been willing to trust Boeing and the FAA; they are willing to board twin-engine aircraft to go pretty much anywhere. But a "drama" (Airbus's word) on live TV (Crippled Airliner Struggles Toward Land! Film at 11!) would obviously spike the A340's popularity; the only question is, for how long?

User currently offlineJet Setter From , joined Dec 1969, posts, RR:
Reply 11, posted (14 years 5 months 1 week 5 days 17 hours ago) and read 2033 times:

The A330 was originally designed to be a short/medium haul airliner, and Airbus put it's money on the A340 as their long-haul type. When the A330 started doing longer flights, Airbus realised that by shrinking it they would have an excellent 767 competitor for Trans Atlantic routes in the A330-200.

However, Airbus is still putting it's name on the A340 as it's true long-haul type. This, I think, is the main reason why the A330 has not been taken further in this direction - it would hurt the A340. I'm sure there are no real techincal reasons why the A330's range couldn't be extended further, but Airbus don't really want to do it.

I believe the A340s range comes from the fact the whole aircraft is managed for efficiency - the engines are from a narrowbody aircraft, they only "sip" the fuel - this is also the reason why the A340 is underpowered - it's very efficient. On the other hand the A330 is overpowered and a real performer - twins have to be over powered because they only have one engine left if one fails. However, being overpowered and having 2 engines is less efficient than having 4 small engines and being a bit underpowered!


User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 12, posted (14 years 5 months 1 week 5 days 3 hours ago) and read 2019 times:
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I bet you think I ignored your question.

I cannot substantiate my claim fully as I have not had an A330 course. I am going on the information supplied by the AI instructors on my 340 course at Toulouse, particularly when we went on a field visit to the 330/340 production line.

Tomorrow I will ask the question of one of our structures engineers who came from Airbus and was involved with the design so........watch this space...........


User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 13, posted (14 years 5 months 1 week 4 days 4 hours ago) and read 2004 times:
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I have now spoken to our ex-A.I. structures guy who says :.......

Originally the A330/340 wings were identical but as both a/c were developed the wing skins have got thicker on the 340. Visually there is no difference (apart from the pylon attachments) and additionally, there is no additional structure in the 330 wing to cater for a heavier engine.

The difference in fuel capacities is attributable a different centre tank arrangement on the 330.


User currently offlineD L X From United States of America, joined May 1999, 11325 posts, RR: 52
Reply 14, posted (14 years 5 months 1 week 3 days 20 hours ago) and read 1981 times:

So, how is this center tank different from on the 330 and 340? (I assume the 340's is bigger; can they put the 340 center tank on the 330?) Does the range of the 340 beat the 330 simply because it is carrying less engine weight?


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User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 15, posted (14 years 5 months 1 week 3 days 20 hours ago) and read 1980 times:
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As I said previously, I haven't had an A330 course, so I don't know. My tame structures man is just that, stuctures, not a systems man

User currently offlineD L X From United States of America, joined May 1999, 11325 posts, RR: 52
Reply 16, posted (14 years 5 months 1 week 3 days 20 hours ago) and read 1982 times:

Well, you've been informative nonetheless. Thanks.


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User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 17, posted (14 years 5 months 1 week 3 days 20 hours ago) and read 1979 times:
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It's been a pleasure, I would have loved to have been able to answer your last question

User currently offlineAb.400 From , joined Dec 1969, posts, RR:
Reply 18, posted (14 years 5 months 1 week 3 days 20 hours ago) and read 1979 times:

The difference about center-fuel tank on 340 and 330 is caused by the fourth landing gear on 340´s.

User currently offlineD L X From United States of America, joined May 1999, 11325 posts, RR: 52
Reply 19, posted (14 years 5 months 1 week 3 days 17 hours ago) and read 1974 times:

So, that's interesting. I guess that would make the 340 center tank smaller? Please correct this since it doesn't make much sense.


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User currently offlineAb.400 From , joined Dec 1969, posts, RR:
Reply 20, posted (14 years 5 months 1 week 3 days 7 hours ago) and read 1963 times:

The A340 has less cargo-capacity than 330, due to the fourth-gear, that also gives room for extra-fuel.

User currently offlineLBSteve From , joined Dec 1969, posts, RR:
Reply 21, posted (14 years 5 months 1 week 3 days 6 hours ago) and read 1956 times:

I believe to have read from a previous issue of ‘Airliners’ magazine, that originally Airbus wanted two different wing designs, one optimized for the A330, the other for the A340. This would have been too expensive at the time hence the development of one common wing being a compromise between the two. I believe that this ‘compromise’ is the main reason that Airbus has developed the 500-600 version of the A340, notice the change in the wing design enhancing long range ability.

User currently offlineLBSteve From , joined Dec 1969, posts, RR:
Reply 22, posted (14 years 5 months 1 week 3 days 6 hours ago) and read 1954 times:

Continuing of my previous: Another motivation for the A340 500-600 series structural enhancement, is that as the B777’s wing was never a compromise, allowing for better overall long-range performance.

User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 23, posted (14 years 5 months 1 week 3 days 1 hour ago) and read 1944 times:
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The Ctr Ldg Gr on the 340 does not effect fuel capacity or cargo capacity as it is located in the unpressurised Wing Gear wheel well. The Wing torque box which is also the ctr fuel tank is fwd of the well & the aft cargo compt is aft of the well behind the pressure bulkhead.

User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 24, posted (14 years 5 months 5 days 20 hours ago) and read 1919 times:
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I have just spoken to someone who has just completed an A330 course, he tells me the 330 has no Ctr fuel tank

25 Post contains images D L X : Ahhhh. Now it all clicks. Thanks again.
26 Post contains images Hamlet69 : This has been a very informative discussion. A big thank you to all of you who have contributed, especially Ual747 for posting the topic to begin with
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