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aircanada014
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Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 11:54 am

Hello all

I was just wondering after looking at some pictures of all differ type of widebody a/c
why do A330 and A340 look like they are slented forward instead of leveled like other a/c in the back ground? You can see LH A340 front of the a/c is a bit lower than the back of the a/c but with other a/c types they aren't slent they are level?


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teme82
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Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 12:00 pm

I think that it's just another way to save space and weight. Having shorter nose wheel structure you can save some space and kg's  Wink
 
theginge
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Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 12:00 pm

Just the way they are built I guess with the nose gear slightly lower. Probably helps aid any tipping issues from offloading the front first!
 
mcdu
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 12:44 pm

Actually is was a design error. The 330/340 were supposed to be level but there was some issues with the initial design that caused it to be uneven. With the freighter they could not have the slope due to the need to move the containers on the main deck aft and fear of them sliding forward on the ground or during landing. To fix this they had to modify the nose gear and thus the new A330F will have an adjusted nose gear door that will accommodate the moved nose gear attach points. Also issue affected the plan to put the A330F crew rest below the cockpit. As a result of the design change the crew rest had to be moved to the upper deck, reducing the available cargo area.

All in all the slope seems to have caused quite a few problems in the long run. Would like to find the genesis of the design flaw and find out if it was a communications issue with the supplier or was it a design flaw.


http://www.accessmylibrary.com/coms2/summary_0286-33318196_ITM
A330-200 Freighter
The aircraft has a distinctive blister on the underside of the nose to accommodate a revised nosegear layout. The existing nose gear assembly is retained, the leg attachment points have been to raise the nose height to address the nose-down pitch that is a characteristic of the A330 (and the A340). This provides a level cabin floor while on the ground, making it easier to load cargo pallets. The new configuration requires a larger gear bay, says Airbus, which could have a bearing on any future passenger-to-freighter conversion programme for the A330 as it is likely to require a similar modification.
 
brightcedars
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RE: Why Aren't A330s And A340s Level To The Ground

Fri Aug 29, 2008 1:09 pm

Isn't it also the case with the B767-400ER?

I'm wondering if it isn't related to these types being stretches of other types e.g. A330/A340 is a stretch of the A300 and B767-400ER is a stretch of the B767-200/300.
 
cloudyapple
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RE: Why Aren't A330s And A340s Level To The Ground

Fri Aug 29, 2008 1:52 pm



Quoting Mcdu (Reply 3):
Actually is was a design error.

I would call it a design feature for the passenger version and a deficiency for the freighter version (which has been fixed) but certainly not a design error. The shorter front gear and the small slope towards the front does not affect the passenger carrying ability or passenger comfort. This has been fixed for the A332F. Looking at the sales figure, it's not an issue at all.

If you look carefully, the line of windows on the A330/A340 slopes up in reference of the plane's fuselage towards the back. It means the actual slope of the cabin floor referencing ground is even larger. I do not know if this is changed for the freighter.


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aircanada014
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 2:47 pm



Quoting BrightCedars (Reply 4):
Isn't it also the case with the B767-400ER?

I'm wondering if it isn't related to these types being stretches of other types e.g. A330/A340 is a stretch of the A300 and B767-400ER is a stretch of the B767-200/300.

I don't think it has to do being a stretched version because B777-300 and B777-200 are leveled not slented forward.


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mcdu
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 2:59 pm



Quoting Cloudyapple (Reply 5):
I would call it a design feature for the passenger version and a deficiency for the freighter version (which has been fixed) but certainly not a design error. .

The article I read in regards to this issue was a hard copy from Flight International. The term used was design error, definitely not a feature. Not sure how it is a Feature as it serves no useful purpose and resulted in a major redesign of the nose gear attach points and the blister or bubble on the nose gear door for the freighter is abysmal. It will cost efficiency for the airplane in both aerodynamics and in useful cargo space. IMHO, it will most likely be one of the key reason the A330F will never be a success. Of course I could be wrong but just don't see airlines buying compromise airplanes when other better options would be available.

If it was not an error then why the huge effort to redesign and the admittance by Airbus to call it a design error?
 
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Stitch
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 3:04 pm



Quoting BrightCedars (Reply 4):
Isn't it also the case with the B767-400ER?

Boeing's ACAP for the 767 family shows the 767-400ER on an "even keel" just like the other members of the 767 family. Also, the percentage variations in the distance between the ground and various points (passenger door, cargo door, etc.) are the same for the 767-400ER as for the rest of the family.
 
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moo
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 3:12 pm



Quoting Mcdu (Reply 3):
Actually is was a design error. The 330/340 were supposed to be level but there was some issues with the initial design that caused it to be uneven.

Design error? No chance, such an 'error' would have been picked up far in advance of it ever becoming ingrained in the design.

Quoting Mcdu (Reply 7):
Not sure how it is a Feature as it serves no useful purpose and resulted in a major redesign of the nose gear attach points and the blister or bubble on the nose gear door for the freighter is abysmal.

Serves no useful purpose?

How about lessens the chance of a center of gravity shift due to poor unloading, avoiding the costly mistake of having an aircraft go tail down on the ground?

How about carries less weight in the air for basically no penalties on the ground?

Quoting Mcdu (Reply 7):
If it was not an error then why the huge effort to redesign and the admittance by Airbus to call it a design error?

The original A330F design back in 2000 didn't have the nose wheel blister - it was only added on this iteration - and I wouldn't call the addition of the blister a 'huge effort to redesign', it was a simple modification for Airbus to make.

If you want my take on why the shorter nose gear arrangement exists, take a look at the commonality between the A300 fuselage forward of the wing and the A330 fuselage forward of the wing. Its largely the same.


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mcdu
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 3:44 pm



Quoting Moo (Reply 9):
Design error? No chance, such an 'error' would have been picked up far in advance of it ever becoming ingrained in the design.

I'll submit this:
http://www.flightglobal.com/articles...ut-levels-cabin-floor-to-ease.html

And this:

http://www.flightglobal.com/articles...330a340-p2f-conversion-market.html

The blister is hideous and will compromise performance. You don't put something like that on the nose of the airplane not pay a performance penalty. If it was such a brilliant idea and aerodynamically advantageous to have then why did they not incorporate the blister into the original design and offer a modification to put the blister on current airframes. It is not a winglet and will decrease the efficiency of the airframe.
 
CV880
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 3:46 pm



Quoting Stitch (Reply 8):
Boeing's ACAP for the 767 family shows the 767-400ER on an "even keel" just like the other members of the 767 family. Also, the percentage variations in the distance between the ground and various points (passenger door, cargo door, etc.) are the same for the 767-400ER as for the rest of the family.

http://www.cruisinaltitude.com/photos/b764roll_out_pics.htm

According to pics in the above link, it doesn't appear to be very even at all......after working around these planes for a few years, there is no similarity of the 764 to the 763, particularly in the aft end, where the rear cargo compartments are significantly higher off of the ground than the forward compartment. The fwd cargo compartments on the two aircraft are similar in relative height, but that's where the similarity ends, The aft bulk cargo compartment is notoriously high off the ground as opposed to that of the 763.
 
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fanoftristars
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 3:59 pm

I think on the 764 they had to raise the main gear to give additional clearance for takeoff and landing for the longer fuselage (it gives the plane a greater rotation angle on take off) but they didn't bother to re-design the front gear and didn't need to. Technically you could say it was a design error because the designers of the original 767-200 didn't plan for a double stretch  Smile

As to the A330-340, I'd believe it's much like the 767 as far as a higher main gear for rotation purposes, but they kept the original A300 gear, or at least the gears design. I'd hardly call it a design error even though maybe flight international did, more a design compromise at the time? Really I'm not expert so what do I know...
 
birdbrainz
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 5:25 pm



Quoting Fanoftristars (Reply 12):
As to the A330-340, I'd believe it's much like the 767 as far as a higher main gear for rotation purposes, but they kept the original A300 gear, or at least the gears design. I'd hardly call it a design error even though maybe flight international did, more a design compromise at the time?

I agree. Maybe they made the main gear larger for engine clearance as well.

As for it being done to avoid tipping, I doubt it. Freighters experience much greater risk of tipping during loading, so if that were the reason, you'd see it on the freighter.

It was easier to leave it slightly nose down, so they did.
 
gigneil
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 5:30 pm



Quoting Mcdu (Reply 7):
It will cost efficiency for the airplane in both aerodynamics and in useful cargo space.

The blister creates new cargo space.... and the negative AOA didn't hurt the plane in getting off the ground.

NS
 
cloudyapple
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 5:52 pm



Quoting Mcdu (Reply 7):
IMHO, it will most likely be one of the key reason the A330F will never be a success.

77 orders in the last 20 months for an aircraft launched 21 years ago, first flew 16 years ago, entered service 14 years ago is not successful then please tell me what is?
 
c680
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 6:09 pm

I may be way off base here, but I seem to remember that most aircraft with a slightly nose down ground attitude (short nose gear) were designed that way because of the wing.

If the wing carries a slightly positive angle of attack compared to fuselage, then you need the fuselage to be at a slightly negative angle of attack on the ground. If you didn't, the aircraft would have to maintain significant downforce with the elevators to prevent it from premature rotation before the correct airspeed - or something like that.

Somebody correct me if I'm going in the wrong direction please!
 
timz
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RE: A330s/A340s Level To The Ground?

Fri Aug 29, 2008 6:14 pm



Quoting Moo (Reply 9):
Serves no useful purpose?

How about lessens the chance of a center of gravity shift due to poor unloading,

Well, yes. The aircraft's CG can now be ... maybe a few centimeters farther aft?
 
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breiz
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Aug 29, 2008 6:17 pm



Quoting Moo (Reply 9):
Quoting Mcdu (Reply 3):
Actually is was a design error. The 330/340 were supposed to be level but there was some issues with the initial design that caused it to be uneven.

Design error? No chance, such an 'error' would have been picked up far in advance of it ever becoming ingrained in the design.

I do not think either that it was a design error as in oversight. The A330/A340 were knowingly designed with a short nose gear.
This became an error when Airbus started to think about the freighter versions. But error as in wrong choice.
 
Viscount724
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RE: Why Aren't A330s And A340s Level To The Ground?

Sat Aug 30, 2008 1:24 am

The slight nose-down attitude of the original DC-8-10 through -50 models made it much easier to stretch the aircraft when they designed the -61/63 models a few years later. The 707 with it's more even stance (or possibly even slightly tail down) would have required major re-design for any significant stretch.
 
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HAWK21M
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RE: Why Aren't A330s And A340s Level To The Ground?

Sat Aug 30, 2008 9:38 am

What would be the Ideal pitch on ground for these types.The B737 classic has a -1 deg pitch.
regds
MEL.
 
dynamicsguy
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RE: Why Aren't A330s And A340s Level To The Ground?

Sat Aug 30, 2008 10:49 am



Quoting Mcdu (Reply 10):

I'll submit this:
http://www.flightglobal.com/articles...ut-levels-cabin-floor-to-ease.html

And this:

http://www.flightglobal.com/articles...330a340-p2f-conversion-market.html

The blister is hideous and will compromise performance. You don't put something like that on the nose of the airplane not pay a performance penalty. If it was such a brilliant idea and aerodynamically advantageous to have then why did they not incorporate the blister into the original design and offer a modification to put the blister on current airframes. It is not a winglet and will decrease the efficiency of the airframe.

I can see no mention of there being a design error in either of those articles, only that the nose down attitude is a characteristic of A330s and A340s. Airbus would have conducted trade studies to look at different options to raise the nose and decided that that was the best - it coud be for weight, or commonality, or the cost of a more comprehensive re-design.

The blister will probably affect the aerodynamics, but I suspect the effect would be fairly small. The effect would have been considered in their studies. It may make the aerodynamics worse, but the cost to performance may have been less than any extra weight which would have to be added to get around the problem. The efficiency advantage of the A330 over the 767 would outweigh the blister's penalty by orders of magnitude.
 
DukeofDashes
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RE: Why Aren't A330s And A340s Level To The Ground?

Sat Aug 30, 2008 6:26 pm

The CR9 also features the lowered nose concept:


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2H4
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RE: Why Aren't A330s And A340s Level To The Ground?

Sat Aug 30, 2008 11:39 pm



Quoting C680 (Reply 16):
If the wing carries a slightly positive angle of attack compared to fuselage, then you need the fuselage to be at a slightly negative angle of attack on the ground. If you didn't, the aircraft would have to maintain significant downforce with the elevators to prevent it from premature rotation before the correct airspeed - or something like that.

Somebody correct me if I'm going in the wrong direction please!

I'm surprised more people haven't brought this up. It seems to me, any effects in weight savings from a shorter nose gear would pale in comparison to the effects a shorter nose gear would produce by altering the deck angle during takeoff.

Consider the Piper Comanche. Although a completely different aircraft, it is commonly modified with a smaller nosewheel to improve takeoff characteristics for reasons that just might be identical to those inspiring the shorter nose gear design on the A330s and A340s.

Does anyone know how the angle of incidence on the 330 and 340 compare with that of the 767?

Quoting DukeofDashes (Reply 22):
The CR9 also features the lowered nose concept:

If I'm not mistaken, I believe the nose was purposely positioned lower on that aircraft to meet certain evacuation requirements.

2H4
 
hloutweg
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Aug 31, 2008 12:06 am



Quoting Mcdu (Reply 3):
Actually is was a design error. The 330/340 were supposed to be level but there was some issues with the initial design that caused it to be uneven. With the freighter they could not have the slope due to the need to move the containers on the main deck aft and fear of them sliding forward on the ground or during landing. To fix this they had to modify the nose gear and thus the new A330F will have an adjusted nose gear door that will accommodate the moved nose gear attach points.

There's nothing in the world to suggest that the forward slope is a disadvantage, much less a design error, for the A330 or A340. If it was, why would Boeing feature a brand new 787 Dreamliner with a slope? The Dreamliner along with some other ailiners feature this 'shorter-nose-gear' concept which reduces the space that the gear bay takes in the lower cabin. Saving every inch allows for maximums space utilization and it could mean that these aircraft might just not have the space to accommodate an extra pallet or LD3. Shortening the gear also saves weight.

The reason why Airbus chose to lower the gear and consequently add a nose-gear fairing, is that it'd be essential for cargo operators to have a leveled floor. Remember that they deal with large and heavy loads that aren't suppose to roll along the cargo cabin. Doing this change on the A330F from the pax version, actually reduces the space the gear bay takes inside the cabin, offers a cheaper production, and doesn't significantly reduce aircraft performance, if at all, with a well designed fairing.
 
NoUFO
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Aug 31, 2008 1:22 am

And here I was thinking Arbus simply used the A300/A310's nose gear as a cost saving measure.
 
474218
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Aug 31, 2008 1:51 am



Quoting Hloutweg (Reply 24):
actually reduces the space the gear bay takes inside the cabin,

Actually the gear bays (nose and main) are no where near the cabin. The nose is under the flight station, forward of the cargo compartment and the mains are in the keelson area aft of the wing box and forward of the mid cargo compartment.
 
hloutweg
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Aug 31, 2008 5:14 am



Quoting 474218 (Reply 26):
Actually the gear bays (nose and main) are no where near the cabin.

You're totally right. I really didn't mean the cargo cabin but inside the fuselage. Heres a graphic to show what's inside this area in the A330. The blue area is the cargo cabin, the yellow is the NLG bay and the red is the avionics bay (this is the area that Airbus thought of assigning as crew rest area instead for the A350 mk.1):



Then I want to show how, officially the gear of the A300 differs from that of the A330.

A300 nose landing gear:
http://farm4.static.flickr.com/3132/2812288583_877f038439_o.png

compared to A330/340
http://farm4.static.flickr.com/3044/2813137868_df60d12d47_b.jpg

The measurements are:

105.98 inches for the A300,and
104.70 inches for the A330/340.

But observe that the main landing gear is different: A300:

http://farm4.static.flickr.com/3264/2812288681_67fce7a13a_o.png

compared to A330/340:

http://farm4.static.flickr.com/3116/2813137896_0fc756ab89_b.jpg


117.05 inches for the A300, and
159.80 inches for the A330/340.

That would explain at least one reason why the A330/340 have a slope. Main landing gear is longer, and that, I suppose, is to accommodate for the A330's engines.

Quoting NoUFO (Reply 25):
And here I was thinking Airbus simply used the A300/A310's nose gear as a cost saving measure.


 checkmark 

as a bonus, here's the 787's nose landing gear:

 
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Starlionblue
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Aug 31, 2008 6:12 am



Quoting Hloutweg (Reply 24):
The reason why Airbus chose to lower the gear and consequently add a nose-gear fairing, is that it'd be essential for cargo operators to have a leveled floor.

Quite. I would add that the fact that it needed to be altered after over 15 years with hundreds of aircraft sold does not make it design flaw. It's hard to imagine the original designers envisaged the current situation. And even if they did, they probably figured that making the plane sellable as a pax carrier would be more important that making it cargo friendly "somewhere down the line".
 
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jetmech
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Aug 31, 2008 6:18 am



Quoting AirCanada014 (Thread starter):



Quoting Mcdu (Reply 7):
If it was not an error then why the huge effort to redesign and the admittance by Airbus to call it a design error?

Could it just be that the particular A340 in the photo is near empty, hence the tilt down towards the nose?. If you look through the database, you can find photos of just about any type, A or B in varying degrees of non-level attitude.

Regards, JetMech
 
FlyASAGuy2005
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Aug 31, 2008 10:50 am



Quoting BrightCedars (Reply 4):
Isn't it also the case with the B767-400ER?

 checkmark 


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Quoting DukeofDashes (Reply 22):
The CR9 also features the lowered nose concept:

As with the CR7.


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With the CRJ700, I was told it was so that they won't need an emergency slide in the front.

I asked the same question about a/c sloping forward a while back:

https://www.airliners.net/aviation-forums/tech_ops/read.main/206169/
 
411A
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RE: Why Aren't A330s And A340s Level To The Ground?

Mon Sep 01, 2008 2:21 am

The apparent forward slant (nose low appearance) of the A340 and A330 while the airplane is on the ground....

It is all quite simple, as carefully reported in the magazine Flight International, when the A340 was first shown to the public.

The longer nose gear, as originally planned, interferred with the forward E&E bay, so it had to be manufactured slightly shorter, to accomodate a slightly shorter forward wheel bay.

Freighter version?
Dunno anything about these.
 
VC-10
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RE: Why Aren't A330s And A340s Level To The Ground?

Mon Sep 01, 2008 5:21 am

There was a cock-up somewhere along the line because when the -300 first came out the fuel tank water drain inlets were in the wrong place.

The problem manifested itself by us getting lots of fuel qty indication system problems. It was found the weekly water drain chks were not getting all the accumulated water out of the fuel tank sumps.

Until a mod was carried to reposition the water drain valve inlets the solution was the jack the nose until the a/c was horizontal, then sump the fuel tanks

Somebody hadn't told the fuel system designers what angle the a/c would sit on the ground at!
 
airbuster
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RE: Why Aren't A330s And A340s Level To The Ground?

Mon Sep 01, 2008 9:48 pm

As with the Fokker 70 and 100....and MD80 series......whatabout the 727?
 
747400sp
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RE: Why Aren't A330s And A340s Level To The Ground?

Fri Sep 05, 2008 12:00 am

It a good look to me. 777 200s, looks a little slope to the ground also.
 
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N14AZ
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Sep 28, 2008 9:45 am



Quoting Cloudyapple (Reply 5):
If you look carefully, the line of windows on the A330/A340 slopes up in reference of the plane's fuselage towards the back. It means the actual slope of the cabin floor referencing ground is even larger. I do not know if this is changed for the freighter.

It's a littlebit off-topic but I thought about this since I read this some weeks ago. Is that really true? I simply cannot imagine that the cabin floor in a tubular fuselage is not installed horizontally. Can anyone help on this? Thanks in advance.
 
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Starlionblue
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Sep 28, 2008 11:00 am



Quoting N14AZ (Reply 35):
It's a littlebit off-topic but I thought about this since I read this some weeks ago. Is that really true? I simply cannot imagine that the cabin floor in a tubular fuselage is not installed horizontally. Can anyone help on this? Thanks in advance.

It is quite true. It slopes up towards the rear. There are several pics in the database that illustrate this.
 
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N14AZ
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Sep 28, 2008 11:56 am



Quoting Starlionblue (Reply 36):
It is quite true. It slopes up towards the rear. There are several pics in the database that illustrate this.

Is the A330/340 the only plane that has this design feature? And what's the reason for this? Does that mean that each cross beam of the cabin floor has a different elevation inside the fuselage?
 
tdscanuck
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Sep 28, 2008 4:52 pm



Quoting N14AZ (Reply 37):

Is the A330/340 the only plane that has this design feature? And what's the reason for this?

It's the only one that comes time mind, but I doubt it's the only one overall.

They do it because of the way the fuselage tapers at the rear..rather than bringing the top and bottom down evenly, they keep the top nearly level and bring the bottom up to meet it. As a result, the widest part of the cabin moves upwards, so they move the floor upwards to match.

Quoting N14AZ (Reply 37):
Does that mean that each cross beam of the cabin floor has a different elevation inside the fuselage?

Only in the tail taper. Through the constant cross-section portion of the body I believe they're all the same.

Tom.
 
474218
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Sep 28, 2008 5:36 pm



Quoting N14AZ (Reply 37):
Is the A330/340 the only plane that has this design feature? And what's the reason for this? Does that mean that each cross beam of the cabin floor has a different elevation inside the fuselage?

All Airbus wide body aircraft, A300, A310, A330 and A340, have the design feature (or defect) depending on your point of view.
 
FlyASAGuy2005
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Sep 28, 2008 10:35 pm

IDK. I always thought the A300 must have been the most ugly mainstream passenger jet looking at it head it in a tight shot.

I'll try to find one...
 
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Starlionblue
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RE: Why Aren't A330s And A340s Level To The Ground?

Sun Sep 28, 2008 11:08 pm



Quoting Tdscanuck (Reply 38):
Quoting N14AZ (Reply 37):

Is the A330/340 the only plane that has this design feature? And what's the reason for this?

It's the only one that comes time mind, but I doubt it's the only one overall.

They do it because of the way the fuselage tapers at the rear..rather than bringing the top and bottom down evenly, they keep the top nearly level and bring the bottom up to meet it. As a result, the widest part of the cabin moves upwards, so they move the floor upwards to match.

AFAIK, cargo space is also increased since you can shove containers further back.

If you look at the 300/310/330/340 the top of the fuse is flat all the way to the APU exhaust. This is not the case with 767 and 777.
 
474218
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RE: Why Aren't A330s And A340s Level To The Ground?

Mon Sep 29, 2008 12:52 am



Quoting Starlionblue (Reply 41):
If you look at the 300/310/330/340 the top of the fuse is flat all the way to the APU exhaust. This is not the case with 767 and 777.

I don't know what the shape of the upper fuselage has to do with the main cabin floor angling up on the Airbus aircraft? But the difference between Airbus and Boeing aircraft is clearly visible in this photo.


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Photo © Erwin

 
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Starlionblue
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RE: Why Aren't A330s And A340s Level To The Ground?

Mon Sep 29, 2008 1:09 am



Quoting 474218 (Reply 42):

I don't know what the shape of the upper fuselage has to do with the main cabin floor angling up on the Airbus aircraft?

I'm no aerodynamicist but I think that it has a lot to do with it. The tail has to taper somehow. On the 300/310/330/340 it tapers to a point at the highest level of the fuselage. This means that, slope being equal, the floor will begin to slope up further forward than on an aircraft where the point is nearer the longitudinal center. It follows that there is less space in the cargo hold because the slope up starts further forward, but this problem can be alleviated by sloping the cabin floor upwards.
 
brons2
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RE: Why Aren't A330s And A340s Level To The Ground?

Mon Sep 29, 2008 2:08 am



Quote:
Sources say that Airbus studied several options for the A330F, including the incorporation of a new longer nosegear leg that articulated to fit into the existing bay geometry. However, this would have reduced commonality with the large in-service fleet of passenger aircraft, so Airbus says that it has adopted a solution based on that planned for the old A350. "We've retained the existing nose gear, but lowered the leg attachment points to raise the nose height," says Airbus.

The longer nosegear leg seems like the more elegant solution, rather than the blister pod.

Yes, it does reduce commonality, but it seems like that if the pod was eliminated, aerodynamics would be improved, ergo reducing operating cost.
 
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Starlionblue
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RE: Why Aren't A330s And A340s Level To The Ground?

Mon Sep 29, 2008 4:06 am



Quoting Brons2 (Reply 44):
Yes, it does reduce commonality, but it seems like that if the pod was eliminated, aerodynamics would be improved, ergo reducing operating cost.

My guess is they decided the loss of commonality plus the need to design and certify a new part from scratch was more costly than the drag penalty.

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