Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Largest Obstacles To Overcome To Build The A380  
User currently offlineCoolGuy From United States of America, joined Jan 2005, 414 posts, RR: 0
Posted (7 years 6 months 3 weeks 6 days 20 hours ago) and read 5557 times:

What were some of the greatest challenges from an engineering standpoint to build the A380? I'm impressed that it was actually accomplished with a wingspan of only 80m (in order to fit into the 80x80m box). Anything else? I know it's an amazing piece of work from an engineering point of view, but why?

33 replies: All unread, showing first 25:
 
User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 1, posted (7 years 6 months 3 weeks 6 days 13 hours ago) and read 5521 times:

Personally, I think the business case would be a bigger obstacle, all companies do research to tell whether something is worth investing in. Airbus would have had to look at it from both the perspective of using current technology or being forced to develop newer technology to bring costs down of the estimated development. If the item costed too much that they couldn't sell enough, it would be a problem. I would suppose Airbus determined that throughout the lifetime of the then-A3XX a certain number of planes could be sold which justified the launch of the program. All companies do stuff like this, whether it is your favorite sodapop or even a tv show.

Quoting CoolGuy (Thread starter):
I'm impressed that it was actually accomplished with a wingspan of only 80m (in order to fit into the 80x80m box).

If we limit ourselves to tube-wing designs, then yes it is impressive. But from what is known about the BWB and other concepts, we have quite a bit of evolving to go.

IMO, it is a bad thing when technology doesn't progress just because not all of it is used practically. By the time current technology cannot keep up, the newer tech would cost way more. This is why I believe companies should bite a bullet more often instead of bitch about their bottomline and ROI's.



The meaning of life is curiosity; we were put on this planet to explore opportunities.
User currently offlineCF188A From , joined Dec 1969, posts, RR:
Reply 2, posted (7 years 6 months 3 weeks 6 days 12 hours ago) and read 5509 times:

Business again.... to manipulate airports and get A380 ready gates. Airbus could not just assume that every International Airport would just welcome it with open arms.

Secondly, weight. Wasn't there a big thing about how many airports needed to strengthen the first 1000ft of runway due to the impact upon landing?


User currently offlineCoolGuy From United States of America, joined Jan 2005, 414 posts, RR: 0
Reply 3, posted (7 years 6 months 3 weeks 6 days 8 hours ago) and read 5454 times:

Quoting CF188A (Reply 2):

Secondly, weight. Wasn't there a big thing about how many airports needed to strengthen the first 1000ft of runway due to the impact upon landing?

I thought the A380 will have less of an impact because the weight is spread out over more landing gear (less per wheel).


User currently offlineAnalog From United States of America, joined Jul 2006, 1900 posts, RR: 1
Reply 4, posted (7 years 6 months 3 weeks 6 days 7 hours ago) and read 5441 times:

Quoting CF188A (Reply 2):
Secondly, weight. Wasn't there a big thing about how many airports needed to strengthen the first 1000ft of runway due to the impact upon landing?

I think it's more an issue of the load-bearing widths of the runways & taxiways.
Check out this old presentation (MS PowerPoint): A380 @ ATL


User currently offlineCymro From United Kingdom, joined May 2005, 91 posts, RR: 0
Reply 5, posted (7 years 6 months 3 weeks 1 day 2 hours ago) and read 5155 times:

Quoting Lehpron (Reply 1):
If we limit ourselves to tube-wing designs, then yes it is impressive. But from what is known about the BWB and other concepts, we have quite a bit of evolving to go.

What is BWB short for?


User currently offlineOly720man From United Kingdom, joined May 2004, 6812 posts, RR: 11
Reply 6, posted (7 years 6 months 3 weeks 1 day 1 hour ago) and read 5137 times:

Quoting Cymro (Reply 6):
What is BWB short for?

Blended wing body



http://oea.larc.nasa.gov/PAIS/BWB.html



wheat and dairy can screw up your brain
User currently offlineJetlagged From United Kingdom, joined Jan 2005, 2565 posts, RR: 25
Reply 7, posted (7 years 6 months 3 weeks 12 hours ago) and read 5039 times:

The biggest technical obstacle for the A380 was keeping it's weight down. Then there was the logistical nightmare of transporting the huge sub-assemblies from factories all round Europe to Toulouse for final assembly. Now there is the grossly under-estimated electrical wiring production problems, not least because of the carte-blanche given to interior designers for different airlines.


The glass isn't half empty, or half full, it's twice as big as it needs to be.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 8, posted (7 years 6 months 3 weeks 11 hours ago) and read 5020 times:

Quoting Jetlagged (Reply 7):
Now there is the grossly under-estimated electrical wiring production problems, not least because of the carte-blanche given to interior designers for different airlines.

Hindsight may be 20/20, but I would say the decision to use incompatible versions of CATIA to design the wiring and the rest of the aircraft was not very wise.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineSaintsman From United Kingdom, joined Mar 2002, 2065 posts, RR: 2
Reply 9, posted (7 years 6 months 3 weeks 10 hours ago) and read 5011 times:

I'm sure the new technology cost a bit to develop however it may have a good chance of being used on the A350. Spend on one project, save on another.

User currently offlineCymro From United Kingdom, joined May 2005, 91 posts, RR: 0
Reply 10, posted (7 years 6 months 2 weeks 3 days 1 hour ago) and read 4865 times:

Quoting Oly720man (Reply 6):
Blended wing body

thanks Oly720man


User currently offlineA320ajm From United Kingdom, joined May 2006, 547 posts, RR: 0
Reply 11, posted (7 years 6 months 2 weeks 11 hours ago) and read 4730 times:

I think it would have been the physics. Is it possible to build such a big aircraft an lift it in the sky? For example, the A380 will have a larger air resistance than other aircraft. This could have affected the terminal velocity, stopping the aircraft from getting enough speed to take off or cruise. This would have also affected the maximum speed.
Feel free to criticise me, i am only 15, but i really like physics.
Thanks
A320ajm



If the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.'
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 12, posted (7 years 6 months 2 weeks 11 hours ago) and read 4727 times:

Quoting A320ajm (Reply 11):
I think it would have been the physics. Is it possible to build such a big aircraft an lift it in the sky? For example, the A380 will have a larger air resistance than other aircraft. This could have affected the terminal velocity, stopping the aircraft from getting enough speed to take off or cruise. This would have also affected the maximum speed.
Feel free to criticise me, i am only 15, but i really like physics.

First of all: Keep loving physics!

But I shall criticize.  Wink The aerodynamics of tubes with wings is well understood. Aerodynamically, the 380 is "just" a scaled up version of the airliners in service today. Double decker designs have been proposed for decades. The main problems have been other than aerodynamics. The 380 may have more air resistance, but it also has more powerful engines and a wing with more lift. All is scaled up in proportion.

Of course there were aerodynamic challenges, such as designing an appropriate wing to fit in the 80x80 box.


Another kind of engineering/physics: materials science, was probably a much bigger challenge than the aerodynamics. Scaling structural strength up to match size is tricky. As far as I know, weight increases faster than size if you scale up, so you have to find lighter materials.


And there are the infamous logistical challenges!



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineJacobin777 From United States of America, joined Sep 2004, 14968 posts, RR: 60
Reply 13, posted (7 years 6 months 1 week 14 hours ago) and read 4537 times:

Quoting Starlionblue (Reply 12):

Another kind of engineering/physics: materials science, was probably a much bigger challenge than the aerodynamics. Scaling structural strength up to match size is tricky. As far as I know, weight increases faster than size if you scale up, so you have to find lighter materials.

...had the A380 been designed now, it probably would have been a much more efficient aircraft-i.e.-probably more CFRP than it has and certainly next generation engines..

....that being said, it would have been financially impossible for Airbus to design/manufacture and build the A320NG, A350XWB and A380 at the same time.....


The A380 and B748 are probably the last two mostly-aluminum jets to be built.....



"Up the Irons!"
User currently offlineAstuteman From United Kingdom, joined Jan 2005, 10109 posts, RR: 97
Reply 14, posted (7 years 6 months 1 week 8 hours ago) and read 4479 times:
Support Airliners.net - become a First Class Member!

Quoting A320ajm (Reply 11):
I think it would have been the physics. Is it possible to build such a big aircraft an lift it in the sky?

A320ajm - welcome to A-net. Hope you enjoy it. You'll learn lots, especially here on Tech-ops.

For what its worth, the A380 has been specifically designed with a very high lift wing.
The A380 is type certified at 569 tonnes (a 747-400 is around 400 tonnes)
The A380 wing has been designed to provide enough lift to give a 625 tonne version of the aircraft the same field, and climb performance as the 747.
(Whether a 625 tonne A380 version is ever built is a different matter).
But that is why the A380 wing is so incredibly large.
In fact, the wing area is so great, that the A380 wing loading (aircraft weight divided by wing area) is much lower than a 747.

The result of this is that the 569 tonne A380 actually has substantially better take-off and climb capability than the 747-400
It also has a lower landing speed  Smile

Quoting A320ajm (Reply 11):
For example, the A380 will have a larger air resistance than other aircraft

It's worth having a bit of care to differentiate between the air resistance and the lift.
One advantage that the huge 80m wingspan confers on the A380 is that it allows it to produce much more lift without a proportional increase in drag (resistance, as you put it).
That capability is a function of the wing span.

Quoting Starlionblue (Reply 12):
Of course there were aerodynamic challenges, such as designing an appropriate wing to fit in the 80x80 box.

Hence comments like this. Airbus would have liked the wing span to be even greater (about 82.5m to 83m I believe), but they promised Airport Authorities around the world that the A380 would fit in an 80m x 80m "box" (without a lid, presumably...  biggrin  )

Quoting A320ajm (Reply 11):
This would have also affected the maximum speed.

This tends to be governed (I understand) by the onset of supersonic shockwaves in the airflow over the aircraft at high speed. When this happens, the drag (resistance) rises dramatically.
That is the reason that the A380 has such a long "forehead" above the cockpit windows.
It gives the airflow much more time to accelerate over that great big body without going supersonic, hence much less drag (resistance) at high speed.

The two guys on A-net that coached me in aerodynamics are OldAeroGuy and Zeke
I'm just regurgitating what they told me  Smile

Regards


User currently offlineZenarcade From Canada, joined Nov 2006, 85 posts, RR: 0
Reply 15, posted (7 years 6 months 6 days 19 hours ago) and read 4416 times:

Amazing post Astuteman! I'm sure many of us have learned something from reading it.

"One advantage that the huge 80m wingspan confers on the A380 is that it allows it to produce much more lift without a proportional increase in drag (resistance, as you put it)."

Could you possibly explain this further?

Wouldn't any additional lateral wing structure and wing paneling along the span naturally cause drag?

[Edited 2007-04-20 06:39:06]


If a plane falls on the tarmac and no one is there, does it make any sound? - Starlionblue
User currently offlineAstuteman From United Kingdom, joined Jan 2005, 10109 posts, RR: 97
Reply 16, posted (7 years 6 months 6 days 14 hours ago) and read 4387 times:
Support Airliners.net - become a First Class Member!

Quoting Zenarcade (Reply 15):
"One advantage that the huge 80m wingspan confers on the A380 is that it allows it to produce much more lift without a proportional increase in drag (resistance, as you put it)."

Could you possibly explain this further?

In reality, you're best talking to OldAeroGuy and Zeke - they're much more "expert" on the matter. Read this thread (on this forum a bit lower down the page...) and prepare to get you head blown apart...  biggrin 

A380 And 748i Drag Comparisons (by Astuteman Feb 23 2007 in Tech Ops)

Grossly oversimplified, total drag comprises of subsets, such as:-
lift drag,
wetted (surface) area drag,
and appendage drag.

The lift drag component is very sensitive to wingspan, and (I'm told) can be expressed as

aircraft weight/the span squared

In other words, if you double the wing span, you reduce the lift drag by a factor of 4!  thumbsup 

Quoting Zenarcade (Reply 15):
Wouldn't any additional lateral wing structure and wing paneling along the span naturally cause drag?

The downside is that the bigger wing is a) heavier, and b) has a bigger wetted area, hence, as you say, the wetted area drag increases.  thumbsdown 

All manufacturers will trade these two conflicts off to achieve the best optimum. (typically, the longer the range, the better a big wingspan optimises)

This is why gliders have huge long, thin wings. it minimises lift drag, and minimises wetted area drag at the same time.

Airbus have said the optimum wing-span for a 625 tonne A380 would have been 82.5m to 85m.
Unfortunately, they were constrained by the 80m "box" that they agreed with the airports.

At this point field performance comes in.
In order to guarantee the take-off and landing capability of the 625 tonne option, Airbus had to achieve a certain wing area in order to generate the lift.
Because the span was constrained, the depth of the wing (from leading edge to trailing edge) is greater than it would typically be (it has a low aspect ratio).
This gives NO advantage in terms of lift drag, but sadly ADDS wetted area drag, AND weight.

The 569 tonne A380 of today is thus saddled with an overly large, overly heavy wing, because Airbus wanted to have the capability to grow the plane to 625 tonnes one day.
Without this, I'm sure the current A380 would still have an 80m wingspan, but with a much "thinner" wing (from front to back), which would be lighter too.

Engineers have a great many variables to juggle when making their decisions, and almost every decision trades a desirable charachteristic against an undesirable one.

Hope that helps.

Regards


User currently offlineFlipdewaf From United Kingdom, joined Jul 2006, 1577 posts, RR: 0
Reply 17, posted (7 years 6 months 5 days 12 hours ago) and read 4309 times:
Support Airliners.net - become a First Class Member!

Quoting Astuteman (Reply 14):
A380 would fit in an 80m x 80m "box" (without a lid, presumably... biggrin )

The box has an 80ft high lid doesnt it?

Fred


User currently offlineAstuteman From United Kingdom, joined Jan 2005, 10109 posts, RR: 97
Reply 18, posted (7 years 6 months 5 days 5 hours ago) and read 4269 times:
Support Airliners.net - become a First Class Member!

Quoting Flipdewaf (Reply 17):
The box has an 80ft high lid doesnt it?

At least whilst stationary or taxiing..  biggrin 
Regards


User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3417 posts, RR: 4
Reply 19, posted (7 years 6 months 2 days 18 hours ago) and read 4169 times:

The retarded management was the biggest obstacle. Or the national politics if you want to play the "chicken or the egg" game.

User currently offlineVorticity From United States of America, joined May 2004, 337 posts, RR: 5
Reply 20, posted (7 years 6 months 2 days 17 hours ago) and read 4163 times:

Quoting CoolGuy (Thread starter):
What were some of the greatest challenges from an engineering standpoint to build the A380? I'm impressed that it was actually accomplished with a wingspan of only 80m (in order to fit into the 80x80m box). Anything else? I know it's an amazing piece of work from an engineering point of view, but why?

$$$

The biggest engineering challenge in commercial aviation is money. The airplane has to be efficient, afforadable and it has to meet a million other constraints that academia never thinks about. (Which is why there are not BWB commercial airliners flying)



Thermodynamics and english units don't mix...
User currently offlineZenarcade From Canada, joined Nov 2006, 85 posts, RR: 0
Reply 21, posted (7 years 6 months 1 day 17 hours ago) and read 4061 times:

Quoting Vorticity (Reply 20):
The biggest engineering challenge in commercial aviation is money.

Money would not be an engineering challenge. Instead it would be a cause for engineering.



If a plane falls on the tarmac and no one is there, does it make any sound? - Starlionblue
User currently offlinePs76 From , joined Dec 1969, posts, RR:
Reply 22, posted (7 years 5 months 2 weeks 2 days 21 hours ago) and read 3849 times:

Hi,

I have also noticed often that the A380 wing also looks too big for the aircraft, but sometimes think it must have been like this becuase the double-deck fuselage is much heavier. However it does seem incredibly big so have wondered if it would fly 0.8M cruise with much more down trim than something like the A340 etc.?

I think making the structure would have been one of the hardest part. Would making a pressure vessel of such large internal volume/non-circular shape not be much harder than fuselages before? I have no real idea how the aluminium fueslage section is built but I'm guessing pieces are put in a frameworks for joining to make circular longitunally spaced ribs and joined with longitudinal long pieces to form the basic framework with skin also riveted on (is the skin not made tight to provide further strength too?). Have once visited the A380 public factory tour in St.Nazaire where there were fuselage sections and the massive volume/non-circle shape looked like it would be much harder to make rigid/strong to me (especially while making light?)

Finally I wonder with the length of the A380 not making it a little less naturally aerodynamically stable - maybe a little more "jittery" (though not unsafe) (I wonder similarly like with the A318). If the aircraft is pivoting about it's center of gravity wouldn't the short wing-tail length not be approaching the desired minimum level. I once saw a video with a GeeBee(?) in it - obviously it's not that extreme by any means but I'm guessing it wouldn't want to be too much shorter? (Although I don't understand why the less pivot length would mean a 'harder' natural stability except by feeling intuitively that it would).

P.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 23, posted (7 years 5 months 2 weeks 2 days 12 hours ago) and read 3809 times:

Quoting Ps76 (Reply 22):
Finally I wonder with the length of the A380 not making it a little less naturally aerodynamically stable - maybe a little more "jitter

Nah. There are other aircraft with such a proportionally short moment arm. For example the 318. No problem. Just larger empennage.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineRwessel From United States of America, joined Jan 2007, 2368 posts, RR: 2
Reply 24, posted (7 years 5 months 2 weeks 1 day 19 hours ago) and read 3746 times:
Support Airliners.net - become a First Class Member!

Quoting Starlionblue (Reply 23):
Nah. There are other aircraft with such a proportionally short moment arm. For example the 318. No problem. Just larger empennage.

The 747SP being another perfect example.


25 Ps76 : Quoting Ps76 (Reply 22): Finally I wonder with the length of the A380 not making it a little less naturally aerodynamically stable - maybe a little m
26 Starlionblue : ???
27 Ps76 : Quoting Ps76 (Reply 25): Nice replies. Very polite/civilized (not)! ??? The replies basically sounded rude to me - more dismissive/arrogant than too
28 Kukkudrill : What gives you that impression? I don't see any rudeness.
29 Starlionblue : It should be well known on the forums that I am not particularly prone to rudeness or condescension. I'm sorry if you got that impression. May I reco
30 Post contains images Astuteman : If you look further up the thread, you'll see a clear and concise (I hope ) explanation of EXACTLY why the A380 wing is the size it is. Reading the t
31 Prebennorholm : "Non-circular" ??? The A380 fuselage is indeed circular. But there are three circles. It is what is called a "triple bubble" design. The upper fusela
32 WingedMigrator : The A380 fuselage has an ovoid cross section. The radius of curvature of the skin varies continuously. It is a "triple bubble" only in the sense that
33 Post contains images Starlionblue : With difficulty, seeing as the slab sides created such troubles when certifying.
Top Of Page
Forum Index

Reply To This Topic Largest Obstacles To Overcome To Build The A380
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Why Is London ATC Said To Be "among The Best"? posted Wed Dec 17 2003 12:10:11 by Mozart
To My Friends In The Tech/ops Forum... posted Wed Jan 29 2003 20:35:36 by NormalSpeed
How Is It To Fly A Cessna For The First Time? posted Mon May 27 2002 00:07:34 by Apuneger
Largest Obstacles To Overcome To Build The A380 posted Fri Mar 30 2007 05:45:44 by CoolGuy
"Driving" The A380 - How Easy Is It? posted Wed Feb 14 2007 11:07:59 by BOACVC10
Can The A380 Land Fully Loaded Pax/fuel Emergency? posted Sat Apr 29 2006 15:37:01 by Julianuk
Noise Levels Of The A380 posted Sat Oct 8 2005 11:53:29 by TheSonntag
What Is This In The Back Of The A380? posted Thu Jun 16 2005 22:40:13 by Alphafloor
The A380 "forehead". A Tech Explanation posted Tue Jun 14 2005 00:32:14 by Pihero
How Many T/R On The A380 posted Thu Apr 28 2005 14:06:38 by JAGflyer

Sponsor Message:
Printer friendly format