Rj111
Posts: 3007
Joined: Wed Sep 08, 2004 9:02 am

How Did Airbus Manage To Get The A345/6 So Heavy

Fri Oct 29, 2004 2:44 am

Seems the Airbus A345 and A346 would be a very competitive product compared to the 773ER and 772LR......if they werent so damn heavy.

The 380Mtow A345 weighs 174.8t, thats roughly 30t more than the 772LR.

And the A346 weighs 181.9t, thats 14t more than the 773ER and even makes it heavier than the 744.

I guess partly the long and narrow fuselage must make the weight/seat ratio poor and also the combined weight of the four engines. But i've heard the A345/6 use more composites than the 777.

Seems that Airbus have shot themselves in the foot here, the A340's have great uplift but as so much of that is contributed to the OEW, all the advantages such as high payload/range are wasted.

Has Airbus considered ways of making these planes lighter?
Should they have maybe gone with a new 10-abrest design which covered the A345/6 and continued up to just below the A380?

[Edited 2004-10-28 20:12:31]
 
rossyboy
Posts: 68
Joined: Wed Oct 27, 2004 11:08 pm

RE: How Did Airbus Manage To Get The A345/6 So Heavy

Fri Oct 29, 2004 2:49 am

Perhaps they should put the same engines as the -300 series to make it lighter! Big grin
Ross X
 
Udo
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RE: How Did Airbus Manage To Get The A345/6 So Heavy

Fri Oct 29, 2004 3:02 am

If they put the -300 vacuum cleaner engines on the -600 that heavy thing wouldn't even reach the runway...  Wink/being sarcastic

I have always wondered why on hell the MTOW is almost 40t above the B773ER! Its weight is certainly one of the "heaviest" disadvantages compared to the B777.


Regards
Udo
Me & You & a Plane Named Blue...
 
trident2e
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RE: How Did Airbus Manage To Get The A345/6 So Heavy

Fri Oct 29, 2004 3:10 am

Your post would read better if you were consistent with your weights and measures. Does the A346 weigh 181.9kgs or 181.9 tonnes? And the A345 must surely weigh more than 174.8kgs!
 
stealthpilot
Posts: 502
Joined: Tue May 11, 2004 4:28 am

RE: How Did Airbus Manage To Get The A345/6 So Hea

Fri Oct 29, 2004 4:06 am

he said "The 380Mtow A345 weighs 174.8t, thats roughly 30t more than the 772LR."
only confusing thig was Mtow... not MTOW. otherwise its 't' everywhere = tonnes.
eP007
 
AvObserver
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Joined: Sat Apr 06, 2002 7:40 am

RE: How Did Airbus Manage To Get The A345/6 So Heavy

Sat Oct 30, 2004 5:01 pm

I read in Flight International recently that weight reduction measures for the A345/6 have been an ongoing effort at Airbus, with most attention focussed on the wing. I agree it's peculiar these two models weigh that much more than a comparable performance 777; perhaps Airbus should direct its teams working on A380 weight reduction and designing the lighter A330-derived fuselage for the proposed 'A350' to parlay some of their work into these two models, as well. Getting the weight down is crucial for better operating economics; just raising MTOW to meet performance guarantees isn't enough because, all other things being equal, the heavier airplane will burn more fuel.
 
trident2e
Posts: 1286
Joined: Sun Dec 28, 2003 3:38 am

RE: How Did Airbus Manage To Get The A345/6 So Heavy

Sat Oct 30, 2004 5:07 pm

Stealthpilot - he edited his post without acknowledging the fact. Originally, the weights he gave were wildly inaccurate.
 
antares
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RE: How Did Airbus Manage To Get The A345/6 So Hea

Sat Oct 30, 2004 5:25 pm

Now that the A345 is routinely flying for more than 19 hours with over 170 passengers and up to four tonnes of freight, one wonders what it could do if it was as lightweight on a pax/pax basis as the 777-300ER/-200LR are and will be.

I think the Boeing advantage in lighter weight design will become especially exciting in the e7s.
 
gigneil
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RE: How Did Airbus Manage To Get The A345/6 So Hea

Sat Oct 30, 2004 8:27 pm

The 380Mtow A345 weighs 174.8t, thats roughly 30t more than the 772LR.

Well, yes, but that's without the auxiliary tanks installed on the 772LR.

The A340-500 has no provision for removing its tanks... they're all standard.

Airbus is diligently trying to lighten the airframe further... new control surfaces, the already lightened wing, and other improvements are bound to be along.

N
 
widebodyphotog
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RE: How Did Airbus Manage To Get The A345/6 So Heavy

Sat Oct 30, 2004 9:05 pm

Actually OEW on in service 777-300ER's are more like 387,000lbs(175,500kg) and A346 are 190,000kg. And at that OEW the A346 is heavier than any passenger 747-400 I have seen. It's fuel burn per hour is also closer to a 747-400 than it is to a 777-300ER.

If you want to look at it from a OEW per seat pov, using the factory numbers the 777-300ER is the clear winner there, and disparity is evident when you look at real aircraft that are actually in service.

The A346 is locked in kind of a spiral of sorts,weight increases fuel burn and on and on it goes. The wing structure is very heavy and has a narrow margin of optimum efficiency. It had to be made very strong, stiff and subsequently very heavy because of the high wing loads it has to routinely endure. 777-300ER and A346 have almost identical wing areas, but of course A346 has a much higher MTOW...you do the math.

Also as for 777-200LR. Right now it looks like it could pull off that SIN-EWR-SIN route with payloads of about 105,000lb Eastbound and 90-95,000lb Westbound. That about doubles what I've seen that SIA is getting on that route.

-widebodyphotog
If you know what's really going on then you'll know what to do
 
gigneil
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RE: How Did Airbus Manage To Get The A345/6 So Hea

Sat Oct 30, 2004 9:08 pm

It's fuel burn per hour is also closer to a 747-400 than it is to a 777-300ER.

According to SAA's research, the 346 features a drastic reduction in fuel burn vs. the 744.

N
 
widebodyphotog
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RE: How Did Airbus Manage To Get The A345/6 So Heavy

Sat Oct 30, 2004 9:21 pm

SAA's A346's burn 3100lbs/hr more fuel than AF's 777-300ER's and 1900-2000lbs/hr less than it's own 747-400's. So fuel burn for A346 is closer to 747-400 than 777-300ER

-widebodyphotog
If you know what's really going on then you'll know what to do
 
lyzzard
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RE: How Did Airbus Manage To Get The A345/6 So Heavy

Sun Oct 31, 2004 1:57 am

The A345 averages about 8 tons/hr in cruise, although less than a 747-400, it does carry a lot less than the jumbo.

As for the weight issues, I've also been wondering why it's so much heavier than a comparable 777-200. I can only guess the weight is from the extra fuel tanks (there are 3 tanks in each wing, in addition to 2 in the belly section and 1 trim tank in the tail), large crew rest compartment, extra landing gear, extra galley space (in SIA aircraft there are 3 galleys), and the additional heavier engines.
 
jeffrito
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RE: How Did Airbus Manage To Get The A345/6 So Hea

Sun Oct 31, 2004 3:53 am

Airbi are a good deal though if you figure the $/ton purchase price!