Moderators: jsumali2, richierich, ua900, PanAm_DC10, hOMSaR

 
GalebG4
Topic Author
Posts: 241
Joined: Fri Oct 19, 2012 11:49 pm

A340 with two GE90’s.

Mon Nov 19, 2018 11:02 pm

Would Airbus make more competitive a340 with two ge90’s same as the on 777-300er.
What do you think?
 
SPREE34
Posts: 1745
Joined: Tue Jun 29, 2004 6:09 am

Re: A340 with two GE90’s.

Mon Nov 19, 2018 11:25 pm

It's called an A330. it just doesn't come with GE90s.
I don't understand everything I don't know about this.
 
User avatar
seabosdca
Posts: 6607
Joined: Sat Sep 01, 2007 8:33 am

Re: A340 with two GE90’s.

Mon Nov 19, 2018 11:41 pm

SPREE34 wrote:
It's called an A330. it just doesn't come with GE90s.


The A330neo with Trent 7000s has very similar range to the A340 classics. No giant 777-size engines needed.
 
User avatar
FlightLevel360
Posts: 406
Joined: Mon Dec 04, 2017 2:26 pm

Re: A340 with two GE90’s.

Mon Nov 19, 2018 11:59 pm

Probably wouldn't fit due to clearance issues. The A340 is lower to the ground compared to the 777. The A340 also angles its nose down on the ground for some reason, while the 777 doesn't.
To me, it will always be:
- Bombardier CSeries
- Airbus A321neoLR and A321neoXLR
- EMBRACER ERJ-170, ERJ-175, ERJ-190, and ERJ-195
- MITSUBUSHI MRJ

Anti narrowbody-long range-twinjet gang. Long live the A380 and 747!
 
User avatar
flee
Posts: 1398
Joined: Mon Oct 12, 2009 8:14 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 12:29 am

FlightLevel360 wrote:
The A340 also angles its nose down on the ground for some reason, while the 777 doesn't.

It re-used the A300's nose gear.
 
User avatar
TWA772LR
Posts: 7412
Joined: Thu Nov 17, 2011 6:12 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 1:30 am

flee wrote:
FlightLevel360 wrote:
The A340 also angles its nose down on the ground for some reason, while the 777 doesn't.

It re-used the A300's nose gear.

Is there an advantage to having it nose down?
When wasn't America great?


The thoughts and opinions shared under this username are mine and are not influenced by my employer.
 
User avatar
FlightLevel360
Posts: 406
Joined: Mon Dec 04, 2017 2:26 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:03 am

TWA772LR wrote:
flee wrote:
FlightLevel360 wrote:
The A340 also angles its nose down on the ground for some reason, while the 777 doesn't.

It re-used the A300's nose gear.

Is there an advantage to having it nose down?


Probably it was just cheaper to build it this way. It will definitely not be as aerodynamic as aircraft that are parallel relative to the ground, but this deficiency is more than negligible for the speed that aircraft travel at.
To me, it will always be:
- Bombardier CSeries
- Airbus A321neoLR and A321neoXLR
- EMBRACER ERJ-170, ERJ-175, ERJ-190, and ERJ-195
- MITSUBUSHI MRJ

Anti narrowbody-long range-twinjet gang. Long live the A380 and 747!
 
Waterbomber
Posts: 849
Joined: Sat Jul 09, 2016 11:51 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:33 am

It's actually called the A350XWB, not the A330neo.
 
User avatar
LoganTheBogan
Posts: 397
Joined: Sat Feb 18, 2017 7:49 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:40 am

Well we know it already exists (A330/A350), however it is worth noting that Airbus did almost get GE90s for the A330.
Anyone who has never made a mistake has never tried anything new.
 
hz747300
Posts: 2419
Joined: Thu Mar 11, 2004 11:38 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:56 am

It'd be neat if they did it on the A346, but otherwise, yes it exists in the A330/A350 brand.
Keep on truckin'...
 
NRT744
Posts: 14
Joined: Tue Feb 01, 2005 10:15 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 3:14 am

From what I read from a source I forgot, the cabin floor of the 330/340 was built at a 3˚ angle so that when the plane was at cruising altitude, the floor would level to 0˚ (because planes tilt their nose up a bit during cruise). The lower nose would make the floor even steeper when it's on the ground, so I don't know why they did that (considering the "hoist" they did on the 330F). I don't recall if there was a mention on the recycling of the 300 wheel... Again, I don't remember the source. Sorry.
 
User avatar
Polot
Posts: 11053
Joined: Thu Jul 28, 2011 3:01 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 3:30 am

The A330/A340 has a nose down pitch on the ground because it has the same size nose gear as the A300 and larger MLG. I’m not sure the nose gear is the exact same as the A300 (I don’t think it is?), but it is using the same nose gear bay so the dimensions are similar. This of course was a cost saving measure in the A330/A340 development.
 
User avatar
seabosdca
Posts: 6607
Joined: Sat Sep 01, 2007 8:33 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 3:50 am

A larger nose gear bay might also have cost a couple of LD3 positions.

The A330F has nose gear that is designed to keep the deck flat when the aircraft is on the ground. That nose gear is too big for the existing gear bay so the A330F has a wart-like fairing over the projecting part.

 
SXDFC
Posts: 2066
Joined: Sun Dec 09, 2007 6:07 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 4:08 am

If Airbus put wings atop of the fuselage and one engine in the front could they call it a A172?
 
rbavfan
Posts: 3638
Joined: Fri Apr 17, 2015 5:53 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 4:09 am

TWA772LR wrote:
flee wrote:
FlightLevel360 wrote:
The A340 also angles its nose down on the ground for some reason, while the 777 doesn't.

It re-used the A300's nose gear.

Is there an advantage to having it nose down?



Yes it cost less to not have to make a new nose gear.
 
User avatar
lightsaber
Moderator
Posts: 20921
Joined: Wed Jan 19, 2005 10:55 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 4:21 am

seabosdca wrote:
SPREE34 wrote:
It's called an A330. it just doesn't come with GE90s.


The A330neo with Trent 7000s has very similar range to the A340 classics. No giant 777-size engines needed.

Yep. The A339 is the twin for the cross section. The -600 proved to be too heavy for the capacity. (Would be for a twin as the cross section just isn't optimal for that many people).


No worries, there is now an A350-1000 that will replace many 77Ws as they are retired.

Lightsaber
I cannot wait to get vaccinated to live again! Warning: I simulated that it takes 50%+ vaccinated to protect the vaccinated and 75%+ vaccinated to protect the vac-hesitant.
 
User avatar
LAX772LR
Posts: 13436
Joined: Sun Nov 09, 2014 11:06 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 6:13 am

LoganTheBogan wrote:
it is worth noting that Airbus did almost get GE90s for the A330.

Source?
I myself, suspect a more prosaic motive... ~Thranduil
 
WIederling
Posts: 9591
Joined: Sun Sep 13, 2015 2:15 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 8:46 am

FlightLevel360 wrote:
TWA772LR wrote:
flee wrote:
It re-used the A300's nose gear.

Is there an advantage to having it nose down?


Probably it was just cheaper to build it this way. It will definitely not be as aerodynamic as aircraft that are parallel relative to the ground, but this deficiency is more than negligible for the speed that aircraft travel at.


The lower wing incidence creates less lift before rotation and thus less induced drag during the take off run.
The effect seems to be not pronounced enough to have negative impact on the A330F ( raised FLG )
Murphy is an optimist
 
WIederling
Posts: 9591
Joined: Sun Sep 13, 2015 2:15 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 8:49 am

seabosdca wrote:
A larger nose gear bay might also have cost a couple of LD3 positions.

The A330F has nose gear that is designed to keep the deck flat when the aircraft is on the ground. That nose gear is too big for the existing gear bay so the A330F has a wart-like fairing over the projecting part.



The A330F nose gear leg is the same as on the regular A330/A340.
The change they made is moving the attachment point down in the fuselage.
Murphy is an optimist
 
gokmengs
Posts: 1283
Joined: Wed Mar 09, 2005 2:48 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 9:35 am

WIederling wrote:
seabosdca wrote:
A larger nose gear bay might also have cost a couple of LD3 positions.

The A330F has nose gear that is designed to keep the deck flat when the aircraft is on the ground. That nose gear is too big for the existing gear bay so the A330F has a wart-like fairing over the projecting part.



The A330F nose gear leg is the same as on the regular A330/A340.
The change they made is moving the attachment point down in the fuselage.


I guess to have the floor flat for cargo, wouldn't that be advantageous for the passenger version as well? Airbus is known to improve and squeeze out gains from their ac for years, I'm surprised they didn't carry this advancement to the pax version. Or I misunderstood and someone can correct me. Thanks
Yaşa Mustafa Kemal Paşa Yaşa, Adın Yazılacak Mücevher Taşa
 
Peterwk146
Posts: 76
Joined: Sat Nov 11, 2017 8:22 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 9:52 am

gokmengs wrote:
WIederling wrote:
seabosdca wrote:
A larger nose gear bay might also have cost a couple of LD3 positions.

The A330F has nose gear that is designed to keep the deck flat when the aircraft is on the ground. That nose gear is too big for the existing gear bay so the A330F has a wart-like fairing over the projecting part.



The A330F nose gear leg is the same as on the regular A330/A340.
The change they made is moving the attachment point down in the fuselage.


I guess to have the floor flat for cargo, wouldn't that be advantageous for the passenger version as well? Airbus is known to improve and squeeze out gains from their ac for years, I'm surprised they didn't carry this advancement to the pax version. Or I misunderstood and someone can correct me. Thanks


I think that we may have gone off topic .....
 
hitower3
Posts: 193
Joined: Fri Oct 21, 2016 9:55 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 9:55 am

gokmengs wrote:
I guess to have the floor flat for cargo, wouldn't that be advantageous for the passenger version as well? Airbus is known to improve and squeeze out gains from their ac for years, I'm surprised they didn't carry this advancement to the pax version. Or I misunderstood and someone can correct me. Thanks


Dear gokmengs,

There is no problem with an inclined floor for a pax aircraft. It becomes an issue only for cargo, where moving heavy pallettes "uphill" becomes more difficult. This issue has been addressed with the lengthened nose gear (including the bulge) on the 332F, or with an active pallette moving system on converted pax 333P2F.

Putting the 332F nose gear on a pax version would add weight, cost and a little drag to the aircraft, while it does not provide any noticeable benefit. That's why it isn't implemented.
 
Peterwk146
Posts: 76
Joined: Sat Nov 11, 2017 8:22 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 9:58 am

seabosdca wrote:
SPREE34 wrote:
It's called an A330. it just doesn't come with GE90s.


The A330neo with Trent 7000s has very similar range to the A340 classics. No giant 777-size engines needed.

I think that you've missed the point - the A330 doesn't carry the same number of passengers as the A340-500/600 can.

The question is a good one - clearly an aircraft that has 2 engines has a clear advantage over an aircraft that has 4 engines to do the same job (maintenance costs, etc.) .
I guess that with a robust weight saving programme and having two GE90's, this A340-600 configuration would have been a robust competitor to the Boeing 777-300.

However, now we have the A350-1000 ....
 
skipness1E
Posts: 4876
Joined: Sun Aug 19, 2007 9:18 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 10:36 am

I think we should build a VC10 with Saturn V rocket engines. That would be a winner. Just my two cents worth......
 
gokmengs
Posts: 1283
Joined: Wed Mar 09, 2005 2:48 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 10:44 am

hitower3 wrote:
gokmengs wrote:
I guess to have the floor flat for cargo, wouldn't that be advantageous for the passenger version as well? Airbus is known to improve and squeeze out gains from their ac for years, I'm surprised they didn't carry this advancement to the pax version. Or I misunderstood and someone can correct me. Thanks


Dear gokmengs,

There is no problem with an inclined floor for a pax aircraft. It becomes an issue only for cargo, where moving heavy pallettes "uphill" becomes more difficult. This issue has been addressed with the lengthened nose gear (including the bulge) on the 332F, or with an active pallette moving system on converted pax 333P2F.

Putting the 332F nose gear on a pax version would add weight, cost and a little drag to the aircraft, while it does not provide any noticeable benefit. That's why it isn't implemented.


Thank you for awesome reply, learned something new.
Yaşa Mustafa Kemal Paşa Yaşa, Adın Yazılacak Mücevher Taşa
 
gokmengs
Posts: 1283
Joined: Wed Mar 09, 2005 2:48 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 10:48 am

I also think the question by the OP is interesting. How would the 340-600 GE-90 compare with 777W. Totally understandable topic for aviation geek forum:)
Yaşa Mustafa Kemal Paşa Yaşa, Adın Yazılacak Mücevher Taşa
 
WIederling
Posts: 9591
Joined: Sun Sep 13, 2015 2:15 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 11:39 am

skipness1E wrote:
I think we should build a VC10 with Saturn V rocket engines. That would be a winner. Just my two cents worth......


I'd assume you want to change like for like and install 4 F1 engines?
Murphy is an optimist
 
Qf648
Posts: 74
Joined: Thu Dec 28, 2017 3:49 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 11:52 am

skipness1E wrote:
I think we should build a VC10 with Saturn V rocket engines. That would be a winner. Just my two cents worth......


Nasa did, its called the space shuttle.
 
Kiwirob
Posts: 13171
Joined: Mon Jun 13, 2005 2:16 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 11:54 am

FlightLevel360 wrote:
TWA772LR wrote:
flee wrote:
It re-used the A300's nose gear.

Is there an advantage to having it nose down?


Probably it was just cheaper to build it this way. It will definitely not be as aerodynamic as aircraft that are parallel relative to the ground, but this deficiency is more than negligible for the speed that aircraft travel at.


What does having the nose closer to the ground when it's on the ground got to do with it's aerodynamics when it's in flight?
 
User avatar
LoganTheBogan
Posts: 397
Joined: Sat Feb 18, 2017 7:49 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 12:01 pm

LAX772LR wrote:
LoganTheBogan wrote:
it is worth noting that Airbus did almost get GE90s for the A330.

Source?


Scroll to 'Missed Opportunity". Airbus were the ones that turned it down.

https://leehamnews.com/2017/12/14/top-a ... more-25654
Anyone who has never made a mistake has never tried anything new.
 
hitower3
Posts: 193
Joined: Fri Oct 21, 2016 9:55 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 1:04 pm

gokmengs wrote:
I also think the question by the OP is interesting. How would the 340-600 GE-90 compare with B77W. Totally understandable topic for aviation geek forum:)


Here my 0,02€ about this question:
It is generally accepted as a fact that, overall, the A340-600 is inferior to a B777-300ER, mainly in terms of CASM. Now let's try to look more into detail how this difference can be explained:

Weight (OEW)
B77W: 168t (9% of which are composites)
A346: 174t

This difference of 6t can be attributed to the fact that the A346 is still a derivative of the 1972 Airbus A300-B1, which has received a significant stretch by over 24m. This length increase required a significant stengthening of the fuselage structure, adding significant weight. The B77W has got a wider fuselage (6,20m vs. 5,64m) which helps to deliver a bigger cabin space for a similar length, while requiring less structural reinforcements thanks to a lower length/diameter ratio.
The A346 wings were also extended by 3,15m over the original wing of the A340-300 by adding a piece at the wing root. Knowing that the original A340-300 wing was already an extended version of the first A340 design because of the switch from the initially planned PW Superfans to the less powerful CFM-56 engines, it is understandable that this upgrade was causing a toll in the form of added weight.
The engines weigh 4x4840kg for the A346 and 2x8283kg, resulting in a difference of ~ 2,8t in favor of the B77W. Better load balancing on the A340 wing by the outer engines may take away a part of this advantage, though.

Aerodynamics
The data shows striking similarities between both aircraft in regards to wing span and surface. Airbus has incorporated a thicker wing resulting in a better initial cruise altitude after takeoff at MTOW. The B77W is generally considered as "almost underwinged", resulting also in a rather high Vapp and V1, limiting its hot and high capabilities. On the other hand, this design saves weight and reduces drag at lower loads. All in all, the average drag on typical missions will not be terribly different between both aircraft.

Engines
This is probably the most significant chapter.
The GE90-115B1 used on the B77W is an evolution of the earlier GE90 variants, which have consistently shown better-than-expected fuel burn vs. initial manufacturer promises. It set records for power, pressure ratio (42:1) and SFC.
The RR Trent 556 used on the A346 on the other hand was a downgraded Trent 700 (as used on A330) and the Trent 800 (as used on earlier B777). This engine was generally technically inferior, showing a lower bypass ratio, lower pressure ratio and resulting in a higher SFC and thrust-to-weight ratio.

Conclusions
From the above, it can be concluded that the specific disadvantages of the A346 vs. the B77W could have been only partially adressed by replacing the four RR Trent 556 by two GE90-115B engines. While the aerodynamics would be on par, there would still be a weight disadvantage of at least 3 tons (plus the weight penalty coming from possible wing reinforcement plus gear extension).
Adding the lower passenger capacity of the A346 to the equation, the cost equation further shifts towards the B77W.

All in all, Airbus would have been better of NOT launching the second generation of the 340, but rather start working on a project similar to the A350 back in the late 1990s.
 
T54A
Posts: 308
Joined: Mon Oct 19, 2015 11:47 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 1:31 pm

And that ladies and gentlemen, is how you answer a question.
T6, Allouette 3, Oryx, King Air, B1900, B727, B744, A319, A342/3/6 A332/3 A359
 
GalebG4
Topic Author
Posts: 241
Joined: Fri Oct 19, 2012 11:49 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:03 pm

“I can remember [Airbus] just rolling their eyes, saying ‘no, why would we want to do that? We’ve got a proper strategy: a four-engine airplane for long-haul, planes for regional flying, all with the same fuselage, all with the same wing, this is an unbeatable strategy.’
“I was flabbergasted. I was stunned by that. It was one of the biggest strategic mistakes we made, missing the turn to twins vs quads,” Leahy says.

Aviation legend has already said everything.
 
User avatar
Kindanew
Posts: 182
Joined: Tue May 30, 2017 11:07 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:20 pm

LAX772LR wrote:
LoganTheBogan wrote:
it is worth noting that Airbus did almost get GE90s for the A330.

Source?


John Leahy mentioned this in an interview with Leham news to mark his retirement.
 
GalebG4
Topic Author
Posts: 241
Joined: Fri Oct 19, 2012 11:49 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:27 pm

Kindanew wrote:
LAX772LR wrote:
LoganTheBogan wrote:
it is worth noting that Airbus did almost get GE90s for the A330.

Source?


John Leahy mentioned this in an interview with Leham news to mark his retirement.


Legend
 
KentB27
Posts: 476
Joined: Fri Oct 02, 2015 2:20 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:48 pm

Kiwirob wrote:
What does having the nose closer to the ground when it's on the ground got to do with it's aerodynamics when it's in flight?


Zip, zero, nada, nothing. Even when the plane is on the ground, being slightly nose down is negligible to aerodynamics at best. If it was a significant disadvantage to aerodynamics, then the CRJ family, DC-9/MD-80/90/717, and A330/A340 probably would have never been made in such a way. It doesn't really matter when the plane spends the overwhelming majority of its time on the ground stationary or taxiing at less than 20 knots. Once the gear is retracted after takeoff then it couldn't possibly matter because the landing gear does not affect the attitude of the aircraft in flight.
 
KentB27
Posts: 476
Joined: Fri Oct 02, 2015 2:20 pm

Re: A340 with two GE90’s.

Tue Nov 20, 2018 2:58 pm

NRT744 wrote:
From what I read from a source I forgot, the cabin floor of the 330/340 was built at a 3˚ angle so that when the plane was at cruising altitude, the floor would level to 0˚ (because planes tilt their nose up a bit during cruise). The lower nose would make the floor even steeper when it's on the ground, so I don't know why they did that (considering the "hoist" they did on the 330F). I don't recall if there was a mention on the recycling of the 300 wheel... Again, I don't remember the source. Sorry.


I don't think the entire cabin floor is sloped on the A330/340 but the back part of it is sloped for sure. The A300/310 also have sloped floors in the rear. You can actually see the slope if you look at the windows on the back of the aircraft. It's not really that noticeable from inside the cabin though. I believe the reason for doing this was to make more room for cargo in the rear of the aircraft.
 
hitower3
Posts: 193
Joined: Fri Oct 21, 2016 9:55 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 4:09 pm

KentB27 wrote:
I don't think the entire cabin floor is sloped on the A330/340 but the back part of it is sloped for sure. The A300/310 also have sloped floors in the rear. You can actually see the slope if you look at the windows on the back of the aircraft. It's not really that noticeable from inside the cabin though. I believe the reason for doing this was to make more room for cargo in the rear of the aircraft.


Dear Kent,
Please let me expand a little.
It is accurate that there is a distinctive slope on the rear part of the cabin of all A300B4 and -600, A310 (all variants), A330, A340. The reason for this particularity is to create sufficient clearance for the rear part of the cargo hold to accomodate LD3 containers. The earliest versions of the A300 (B1 and B2) did not implement this optimization and had a smaller rear cargo hold, consequently.

But even on the other parts of the cabin, an uphill slope is noticeable. This results from the fact that the upgrade from A300 to A330/A340, a new wing was designed. This wing would not only feature more wing area and span, but also attach a higher main landing gear. The reason for this lenghtening was to provide more ground clearance for the bigger engines on the A330 and to allow for a sufficient rotation angle on the (longer!) A330-300 and A340-300.

The nose landing gear was not extended likewise on the A330/A340, because it would have involved a major redesign of the nose area (cost!) and potentially even reduced the front cargo hold capacity. The resulting nose-down attitude on the ground was rightfully considered a non-issue for passenger operations.

When the A330-200F was designed, the previous non-issue became an issue, as the main deck pallettes would be difficult to load "uphill". Therefore the bulge was developed as a fix. Later, an active pallette moving system was implemented for A330 P2F conversions, these converted freighters do not have the bulge because they don't need it.

Hope this clarifies a little.

Hendric
 
User avatar
Devilfish
Posts: 7202
Joined: Tue Jan 24, 2006 7:52 am

Re: A340 with two GE90’s.

Tue Nov 20, 2018 6:46 pm

May not actually be the OP engine in the pic, but I could imagine the GE90s almost touching the pavement under an A340..... :eyepopping: .....

Image
https://thumbs.dreamstime.com/z/large-j ... 538099.jpg
"Everyone is entitled to my opinion." - Garfield
 
mr02
Posts: 190
Joined: Wed Jul 11, 2018 2:51 pm

Re: A340 with two GE90’s.

Wed Nov 21, 2018 8:12 am

It will become an A330. Don't see the point of putting the engines on because the A340 is an old aircraft,with older technology and older composites do it will become uneconomical for airlines.
 
gokmengs
Posts: 1283
Joined: Wed Mar 09, 2005 2:48 am

Re: A340 with two GE90’s.

Wed Nov 21, 2018 10:38 am

hitower3 wrote:
gokmengs wrote:
I also think the question by the OP is interesting. How would the 340-600 GE-90 compare with B77W. Totally understandable topic for aviation geek forum:)


Here my 0,02€ about this question:
It is generally accepted as a fact that, overall, the A340-600 is inferior to a B777-300ER, mainly in terms of CASM. Now let's try to look more into detail how this difference can be explained:

Weight (OEW)
B77W: 168t (9% of which are composites)
A346: 174t

This difference of 6t can be attributed to the fact that the A346 is still a derivative of the 1972 Airbus A300-B1, which has received a significant stretch by over 24m. This length increase required a significant stengthening of the fuselage structure, adding significant weight. The B77W has got a wider fuselage (6,20m vs. 5,64m) which helps to deliver a bigger cabin space for a similar length, while requiring less structural reinforcements thanks to a lower length/diameter ratio.
The A346 wings were also extended by 3,15m over the original wing of the A340-300 by adding a piece at the wing root. Knowing that the original A340-300 wing was already an extended version of the first A340 design because of the switch from the initially planned PW Superfans to the less powerful CFM-56 engines, it is understandable that this upgrade was causing a toll in the form of added weight.
The engines weigh 4x4840kg for the A346 and 2x8283kg, resulting in a difference of ~ 2,8t in favor of the B77W. Better load balancing on the A340 wing by the outer engines may take away a part of this advantage, though.

Aerodynamics
The data shows striking similarities between both aircraft in regards to wing span and surface. Airbus has incorporated a thicker wing resulting in a better initial cruise altitude after takeoff at MTOW. The B77W is generally considered as "almost underwinged", resulting also in a rather high Vapp and V1, limiting its hot and high capabilities. On the other hand, this design saves weight and reduces drag at lower loads. All in all, the average drag on typical missions will not be terribly different between both aircraft.

Engines
This is probably the most significant chapter.
The GE90-115B1 used on the B77W is an evolution of the earlier GE90 variants, which have consistently shown better-than-expected fuel burn vs. initial manufacturer promises. It set records for power, pressure ratio (42:1) and SFC.
The RR Trent 556 used on the A346 on the other hand was a downgraded Trent 700 (as used on A330) and the Trent 800 (as used on earlier B777). This engine was generally technically inferior, showing a lower bypass ratio, lower pressure ratio and resulting in a higher SFC and thrust-to-weight ratio.

Conclusions
From the above, it can be concluded that the specific disadvantages of the A346 vs. the B77W could have been only partially adressed by replacing the four RR Trent 556 by two GE90-115B engines. While the aerodynamics would be on par, there would still be a weight disadvantage of at least 3 tons (plus the weight penalty coming from possible wing reinforcement plus gear extension).
Adding the lower passenger capacity of the A346 to the equation, the cost equation further shifts towards the B77W.

All in all, Airbus would have been better of NOT launching the second generation of the 340, but rather start working on a project similar to the A350 back in the late 1990s.

Thanks for the insightful reply. got it:)
Yaşa Mustafa Kemal Paşa Yaşa, Adın Yazılacak Mücevher Taşa
 
mjoelnir
Posts: 9411
Joined: Sun Feb 03, 2013 11:06 pm

Re: A340 with two GE90’s.

Wed Nov 21, 2018 11:48 am

The A340-200/300 had no fuel burn disadvantage against the 777-200/200ER.
That bird has the twin version A330 that as the A330-800/900 is today as capable as the A340-200/300 at a lower fuel burn.

The big difference comes with the A340-500/600 against the 777-200LR/300ER.
There is a big part not the engines, but the frames came out overweight. So it would have helped little to have the same engines as the 777, they would have come out worse in fuel burn anyway. They would than also not have filled the hot and high niche the A340-600 managed to fill.

Today there is the A350, having taken the place of the A340.
 
User avatar
keesje
Posts: 14118
Joined: Thu Apr 12, 2001 2:08 am

Re: A340 with two GE90’s.

Wed Nov 21, 2018 12:11 pm

This is not a GE90, but a Trent900

Image

Only1 and different purpose.
"Never mistake motion for action." Ernest Hemingway
 
mjoelnir
Posts: 9411
Joined: Sun Feb 03, 2013 11:06 pm

Re: A340 with two GE90’s.

Wed Nov 21, 2018 2:03 pm

NRT744 wrote:
From what I read from a source I forgot, the cabin floor of the 330/340 was built at a 3˚ angle so that when the plane was at cruising altitude, the floor would level to 0˚ (because planes tilt their nose up a bit during cruise). The lower nose would make the floor even steeper when it's on the ground, so I don't know why they did that (considering the "hoist" they did on the 330F). I don't recall if there was a mention on the recycling of the 300 wheel... Again, I don't remember the source. Sorry.


The nose landing gear (NLG) has nothing to do with the angel the A330/340 flies at cruising altitude. All the A300/310/330/340 have the same dimensioned NLG and all have the nose down attitude.
All of them also have the trim tank in the elevator that have a big influence on the angle the plane uses at cruising altitude.

The A330-200/300 is a A340-200/300 with 2 engines.

My personal believe is, that the main mistake when the A340-500/600 was designed was, that Airbus kept the A300 dimensioned fuselage and stretched it to over 75 m length.
The long narrow tube just became to heavy. A new shorter fuselage design, with a larger diameter, could IMO have produced a lighter frame for the same number of passengers That frame could have been done with wings, that as in the A330/340, would have had the possibility for 4 or 2 engines, as at that time ETOPS beyond 120 minutes was not yet accepted, but would have offered the possibility for the growing size of engines. The landing gear configuration would have given such a frame the possibility to grow past the 777 in size.
 
harleydriver
Posts: 91
Joined: Tue May 18, 2010 1:09 pm

Re: A340 with two GE90’s.

Wed Nov 21, 2018 2:27 pm

Kiwirob wrote:
FlightLevel360 wrote:
TWA772LR wrote:
Is there an advantage to having it nose down?


Probably it was just cheaper to build it this way. It will definitely not be as aerodynamic as aircraft that are parallel relative to the ground, but this deficiency is more than negligible for the speed that aircraft travel at.


What does having the nose closer to the ground when it's on the ground got to do with it's aerodynamics when it's in flight?


Having the nose physically closer to the ground would not cause any aerodynamic issues in flight, but using the A330F nose gear arrangement would have the bulge below the nose gear and therefore create a small aerodynamic penalty. I believe thats what the poster was getting at.
Department of Redundancy Department
 
mjoelnir
Posts: 9411
Joined: Sun Feb 03, 2013 11:06 pm

Re: A340 with two GE90’s.

Wed Nov 21, 2018 2:43 pm

harleydriver wrote:
Kiwirob wrote:
FlightLevel360 wrote:

Probably it was just cheaper to build it this way. It will definitely not be as aerodynamic as aircraft that are parallel relative to the ground, but this deficiency is more than negligible for the speed that aircraft travel at.


What does having the nose closer to the ground when it's on the ground got to do with it's aerodynamics when it's in flight?


Having the nose physically closer to the ground would not cause any aerodynamic issues in flight, but using the A330F nose gear arrangement would have the bulge below the nose gear and therefore create a small aerodynamic penalty. I believe thats what the poster was getting at.


The A330 converted freighters, P2F, do not use A330F NLG arrangement. They use a powered floor instead. For the passenger frame I do not see an advantage or disadvantage in the shorter NLG. Perhaps there is some difference in the take off and landing performance.

They bulge arrangement on the A330F does show, that Airbus is rather moving the NLG around than changing it.
 
User avatar
DrPaul
Posts: 141
Joined: Sun Dec 04, 2016 7:21 pm

Re: A340 with two GE90’s.

Wed Nov 21, 2018 4:03 pm

hitower3 wrote:
All in all, Airbus would have been better of NOT launching the second generation of the 340, but rather start working on a project similar to the A350 back in the late 1990s.


This does perhaps show a rather unimaginative view on Airbus' part. And it was definitely shown when the A350 was first mooted, as it was originally little more than an upgraded A330.
 
FatCat
Posts: 1038
Joined: Thu Apr 05, 2018 2:02 pm

Re: A340 with two GE90’s.

Wed Nov 21, 2018 4:07 pm

mjoelnir wrote:
Today there is the A350, having taken the place of the A340.

in our heads
but not in our hearts.
:weeping:
Aeroplane flies high
Turns left, looks right
 
Blotto
Posts: 133
Joined: Mon Sep 28, 2015 7:00 am

Re: A340 with two GE90’s.

Wed Nov 21, 2018 4:19 pm

GalebG4 wrote:
Would Airbus make more competitive a340 with two ge90’s same as the on 777-300er.
What do you think?


Since this has been answered, I want to change the question a bit:

Would Airbus make more competitive a340 with four CFM Leap 1A same as the on A321neo.
What do you think?
 
User avatar
seabosdca
Posts: 6607
Joined: Sat Sep 01, 2007 8:33 am

Re: A340 with two GE90’s.

Wed Nov 21, 2018 5:52 pm

Blotto wrote:
Would Airbus make more competitive a340 with four CFM Leap 1A same as the on A321neo.
What do you think?


Would save a lot of fuel, but still wouldn't be competitive with the A350 overall.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos