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morrisond
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A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 11:51 am

I am starting this new thread as apparently we need to keep the A350F thread pure and not discuss it's competition.

While there is very limited information on a potential A350F many people in here have made pretty good guesses on what it's capabilities will be.

One interesting point is that 777ERSF seems to be quite light at about 152T OEW losing about 16T in the conversion to a freighter. This is only about 9T more than an 777F. One would have to assume that it does not need as much structural reinforcement as it can only lift about 101T in about 25% more volume than an 777F. For reference the OEW weight of an 777LR and 777F are about the same at 145T and 144T respectively.

777ERSF specs https://www.iai.co.il/drupal/sites/defa ... ochure.pdf

If you are going to build a clean sheet freighter to compete in the package space - the 777ERSF is going to be tough to beat on a lifetime cost due to it's low capital cost.

The question becomes where do you position an A350F or 778XF? Personally I think you need to position them with as much flexibility and capability as you can possibly give them.

For the 778XF I assume this includes boosting the MTOW to 360T as rumoured with the 777-10. The 777X does have a new stronger wingbox and new stronger gear. It's Achilles heel will be empty weight. At about 70M it would have about 15% more Volume than an 77F. An 778 passenger model of this length will probably be about the weight of an 77W - so lets call the 778XF about 168T Empty. This leaves 192T for fuel and Cargo. 10 Hours of fuel at about 6.5T per hour plus reserves should be about 72T - call it 75T ton total which leaves 117T for cargo. That seems about right and roughly the same density as 77F.

So how does Airbus counter both?

An 319T A350-950F of similar volume at 70M should have an OEW weight at around 140T. That leaves 179T for Fuel and Cargo it should burn less but not that much less on long missions. It doesn't have as big and efficient a wing and it's engines are half a generation behind. Lets say it burns 70T leaving 109T for cargo. However 109T of cargo would put MLW at 260T with some reserves. That is way about the capabilities of the current structure and may be why some of the rumoured MTOW's are not 319T. The 140T OEW weight may have to grow a bunch if it wants to carry any density.

Hence why I think A350F OEW and MTOW weight have to grow. It will be efficient but won't be able to compete with 777ERSF for packages or 778XF for flexibility.

How heavy will an A350F structure need to get to lift 110-120T and would it work better in an -1000 length if you one decides density is not as important.

Sorry I have to run - so probably lots of typos above.
 
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Revelation
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 4:34 pm

https://cargofacts.com/airbus-nears-lau ... r-program/ has been posted already, and IMO has an interesting if perhaps flawed chart.

Image

Would be nice to see payload vs range rather than payload vs volume, IMO. Range would be impacted by OEW whereas volume is not. Of course all of these numbers are subject to manipulation, and there has been some pushback that some are incorrect, yet it's a good visualization so if stuff is wrong ideally it would be corrected. Perhaps the nice thing about volume is that it is not subject to manipulation, but it's not as informative as range IMO.

https://www.ainonline.com/aviation-news ... rsion-a350 says:

Faury provided scarce technical details, other than that the A350 F will feature a payload capability of at least “90-plus tonnes” and be a derivative of the larger A350-1000.

Unfortunately that doesn't tell us much about where to put the A350F dot on the chart other than somewhere above the 90T line. Knowing it's a "derivative" of the A350-1000 doesn't tell us much about its volume, since it could be a shorter derivative.

We also don't know where to put 77XF's dot, other than knowing 778 is longer than 772 and there was a statement about favoring volume over max range since most cargo is low density.
 
VV
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 4:56 pm

Why is the title "A350F vs 777XF vs 777ERSF"?

THe A350F has to be compared to the 777-8F.
 
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Revelation
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 5:02 pm

VV wrote:
Why is the title "A350F vs 777XF vs 777ERSF"?

THe A350F has to be compared to the 777-8F.

Because (a) we aren't sure the freighter coming out of the 777X program will be the same length as the 777-8 and (b) one can make a good argument that the 777-300ERSF undermines the business cases of both new freighters since you should be able to buy two of them for each of the new ones.
 
Okcflyer
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 5:05 pm

VV wrote:
Why is the title "A350F vs 777XF vs 777ERSF"?

THe A350F has to be compared to the 777-8F.


Because the 77W is directly competitive.
 
744SPX
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 6:55 pm

What doesn't seem to add up here is that the 777F is only 1 ton lighter than the 200LR whereas the non-purpose-built 777-300ERSF drops 16 tons from the 300ER.

That implies that a 200LRSF could drop at least 10-12 tons from the 200LR and be superior to the 777F, at least in payload capability.
 
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keesje
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 7:20 pm

At an estimated OEW of 150t and the -1000's MTOW of 316t, a 100t+ payload seems likely for a A350-950F.

https://www.reuters.com/business/aerosp ... 021-07-29/
 
Okcflyer
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 7:58 pm

744SPX wrote:
What doesn't seem to add up here is that the 777F is only 1 ton lighter than the 200LR whereas the non-purpose-built 777-300ERSF drops 16 tons from the 300ER.

That implies that a 200LRSF could drop at least 10-12 tons from the 200LR and be superior to the 777F, at least in payload capability.


The 77F uses a ridiculously heavy all aluminum floor and beam system. It was not highly weight optimized as additional payload is/was not needed, and it supposedly provides lower maintenance for spills, house/animal pee, etc that accidentally happen.

The special freighters are keeping the passenger composite beams with, supposedly anyway, some targeted reinforcements to allow usual densities.

I feel the general consensus is IAI will come in a bit overweight, but that an SF -200LR will still be significantly lighter than an a factory fresh F.

Big question mark on the SF is how well do they hold up structurally, and how much repair work is required during heavy visits. If they perform well, then Boeing was probably overly cautious with the 77F.
 
morrisond
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Re: A350F vs 777XF vs 777ERSF

Sat Aug 07, 2021 8:54 pm

keesje wrote:
At an estimated OEW of 150t and the -1000's MTOW of 316t, a 100t+ payload seems likely for a A350-950F.

https://www.reuters.com/business/aerosp ... 021-07-29/


That article had some interesting numbers and statements.

"Calhoun also said on Wednesday exemptions may be allowed for deliveries of current freighters that result in 40% lower emissions compared to the planes they replace."

Could they be allowed to produce 77F and 763F longer than 2028?

and

"Industry sources said the A350 freighter would carry 109 tonnes compared with the projected 115-117 tonne capacity of the 777X version, though Boeing has yet to finalize any plans.

That's funny on the capacities - my guess was about 109T for A350F and 117T for 778XF, as well above. I had not read that article before.

It still makes me think that a 340T A351F with a thrust bump is the way to go.
 
744SPX
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Re: A350F vs 777XF vs 777ERSF

Sun Aug 08, 2021 12:24 am

117T is a perfect 744 replacement. Volume should about match the 744 as well.
 
morrisond
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Re: A350F vs 777XF vs 777ERSF

Sun Aug 08, 2021 12:06 pm

744SPX wrote:
117T is a perfect 744 replacement. Volume should about match the 744 as well.


Yes it and that is far above the guesses some were speculating for the 777xf and the A350F seems more capable as well.

However the A350F could be sticking with a lower MTOW which would put it in the mid 90T range. Maybe they don't want to do the changes necessary to increase the MLW weight. That much.

To allow 109T in an A350F may require significant strengthening that is not there in the base design. There is a reason the passenger designs are so efficient and that may be due to there being so light for there volume compared to the 777 Series.
 
VV
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Re: A350F vs 777XF vs 777ERSF

Sun Aug 08, 2021 7:08 pm

Revelation wrote:
VV wrote:
Why is the title "A350F vs 777XF vs 777ERSF"?

THe A350F has to be compared to the 777-8F.

Because (a) we aren't sure the freighter coming out of the 777X program will be the same length as the 777-8 and (b) one can make a good argument that the 777-300ERSF undermines the business cases of both new freighters since you should be able to buy two of them for each of the new ones.


And do we have anything on the A350F??????
 
VV
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Re: A350F vs 777XF vs 777ERSF

Sun Aug 08, 2021 7:09 pm

Okcflyer wrote:
VV wrote:
Why is the title "A350F vs 777XF vs 777ERSF"?

THe A350F has to be compared to the 777-8F.


Because the 77W is directly competitive.


Come on man, one is around since many years and the other has just been offered.
THere is a difference of ONE generation between the two.
 
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Revelation
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Re: A350F vs 777XF vs 777ERSF

Sun Aug 08, 2021 7:18 pm

VV wrote:
And do we have anything on the A350F??????

As per #2 above:

Faury provided scarce technical details, other than that the A350 F will feature a payload capability of at least “90-plus tonnes” and be a derivative of the larger A350-1000.

Almost nothing.

VV wrote:
Come on man, one is around since many years and the other has just been offered.
THere is a difference of ONE generation between the two.

Right, but the chart in #2 suggests they will be very similar in payload and volume.

Being a generation newer than 77W and having lower fuel burn and emissions is a plus for A350F, but purchase cost presumably 2x or greater with similar payload and volume is a big plus for 77W.
 
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reidar76
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Re: A350F vs 777XF vs 777ERSF

Sun Aug 08, 2021 10:27 pm

If we stich together what "industry sources" have told Reuters, and what information Leeham news is reporting, we can place the A350F and 777XF in the same chart that Revelation posted earlier.

Reuters's sources say the maximum payload for the A350F will be 109t, while the 777XF might be between 114t and 117t. Leeham reports that the A350F will be a shortened A350-1000, halfway between the -900 and -1000 in lenght. They estimate that the A350F will be 230ft long (just over 70 meters). They also report that the 777XF will be longer than the 777-8, and estimate it will be 227ft (about 69 meters).

Since the A350 has a slightly narrower fuselage, the total volume for the 777 would be higher, even though the 777 fuselage tapers significantly more towards the rear. The 777 fuselage is circular shaped with a diameter of 6.2 meters, while the A350 is slightly taller than wide; 5.96 wide and 6.09 tall. (In inches the difference between the two fuselages are between 4 to 9 inches.)

Image

Considering the fuselage dimensions, it looks like the A350 will be able to handle the same pallets in the same configuration as the 777. The contours will be very similar. Since there will be a little bit less clearance for the pallets in the A350F, the slightly longer fuselage could help when it tapers towards the rear. It could be that the A350F and the 777XF can handle the same number of 96 x 125 x 118 pallets. I can't see any reason why 777F ground equipment couldn't be used on the A350F.

The one thing we don't know much about is range. I will guess that the lower OEW of the A350F might give it more range, especially when carrying less than maximum payload.

An important advantage for 777XF would be commonality with the 777F, including a shared pilot pool. Maybe single pilot cruise would be an important advantage for the A350F, an advantage that can't be copied by Boeing without possibly breaking commonality with the 777F.

I also will guess that the A350 family will have a higher total production rate than the 777X family. Production costs for the A350F and 777XF might not be all that different.

It looks like we will have a bloodbath. ;-)

Sources:
https://leehamnews.com/2021/04/06/boein ... hreatened/

https://www.reuters.com/business/aerosp ... 021-07-29/
 
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Re: A350F vs 777XF vs 777ERSF

Sun Aug 08, 2021 11:08 pm

reidar76 wrote:
If we stich together what "industry sources" have told Reuters, and what information Leeham news is reporting, we can place the A350F and 777XF in the same chart that Revelation posted earlier.

Not sure why the 'img' tags in your post didn't work for me as intended. but when I put the full url into my browser:

https://am3pap005files.storage.live.com/y4mi7t2JHx59Ai24cuUalSa76NvhBzV1PyImtoILdU2PIurqzHI8CUC897z1ePKbHVqwnlyIKab31D9qfdlKIuKcEZGnuRHayEBN7wPqKJUxqBDsOb71F0K2MQVp3wGdAgoNM3bjNqddPjfVpYsB_ztRn_B8zkecJnDOQzs7ljn4Js?width=793&height=493&cropmode=none


... a PNG file was downloaded and I could view it.

I guess morrisond's comment stands, if they can get this much more payload out of an A350 either the 'F' is going to be a very different model structurally, or they have really an amazing amount of margin left in the base A350 after doing several MTOW bumps already.
 
flipdewaf
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Re: A350F vs 777XF vs 777ERSF

Mon Aug 09, 2021 11:30 am

My take on the freighters compared here is as below in the chart.
Image

if we assume the 4000nm trip is about 10hrs use and then assume that the fuel burns are associated with that usage as seen above then the A35F is about 6.1t/hr the ERSF 8.3 and the 777XF is 6.8.

at the current fuel price of $613 per ton and 10hrs per day utilisation over 22years the A35F costs 300m in fuel, the ERSF 409m and the 777XF 335m.

The ERSF would appear to be better on low utilisation models the 777XF would be best for the traditional 747 heavy lift scenario and the A35F on the scheduled low density package work as I have described here.

Fred
 
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Revelation
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Re: A350F vs 777XF vs 777ERSF

Mon Aug 09, 2021 2:34 pm

flipdewaf wrote:
My take on the freighters compared here is as below in the chart.
Image

For A350F payload we have Faury saying 90T+, you saying 95T, Reuters saying 109T. I'm not criticizing, but I am looking forward to the time when we have better information. Hopefully this happens by end of 2021, or my comparisons to NMA become more valid! :biggrin:
 
744SPX
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Re: A350F vs 777XF vs 777ERSF

Mon Aug 09, 2021 4:44 pm

My guess is that a 117T payload 778F will be at 778 passenger length. Any longer and I think it will start sacrificing payload. It would have plenty of volume at that length so I don't see any need to make it longer (and have a third fuselage length)
 
oschkosch
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Re: A350F vs 777XF vs 777ERSF

Mon Aug 09, 2021 5:30 pm

Leehamnews confirms that potential customers have seen the details. And even more surprisingly (or maybe not?) Airbus is now offering an A321F. Most part requires a subscription though!


[quote]
When announcing the program launch, Airbus didn’t reveal customers. Nor did officials reveal specifications, beyond saying payload will be “in excess of 90 tons.” But information obtained by LNA and analysis by our Bjorn Fehrm revealed the fundamentals in previous paywall articles. And, we know potential customers have seen the specifications under Non-Disclosure Agreements.
.

It’s also unlikely the Airbus Board would have authorized the program launch without customers ready to go. LNA believes Airbus needed 50 orders to launch the program. With an installed base of combination carriers already operating the A350, these would be target launch customers. Nw LNA can reveal, Airbus is talking with key customers about potentially offering a new-build A321neo freighter.

https://leehamnews.com/2021/08/09/exclu ... more-37246

Gesendet von meinem SM-G950F mit Tapatalk
 
flipdewaf
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A350F vs 777XF vs 777ERSF

Mon Aug 09, 2021 7:49 pm

Revelation wrote:
flipdewaf wrote:
My take on the freighters compared here is as below in the chart.
Image

For A350F payload we have Faury saying 90T+, you saying 95T, Reuters saying 109T. I'm not criticizing, but I am looking forward to the time when we have better information. Hopefully this happens by end of 2021, or my comparisons to NMA become more valid! :biggrin:

Couldn’t agree more, it’s all a bit “everyone says they want a new freighter” and not “here’s what the thing actually is” the biggest thing I got from the numbers that I put together was probably that 360t may well be required. The empty weight of these things is the real unknown(as it always is).


744SPX wrote:
My guess is that a 117T payload 778F will be at 778 passenger length. Any longer and I think it will start sacrificing payload. It would have plenty of volume at that length so I don't see any need to make it longer (and have a third fuselage length)

I think if they got to 360t MTOW then the 778x doesn’t exist as a pax variant. The 779x at 360t would have a pad and bags range of getting on for 8knm leaving no real room for the 8X

Fred


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744SPX
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Re: A350F vs 777XF vs 777ERSF

Mon Aug 09, 2021 10:01 pm

flipdewaf wrote:
Revelation wrote:
flipdewaf wrote:
My take on the freighters compared here is as below in the chart.
Image

For A350F payload we have Faury saying 90T+, you saying 95T, Reuters saying 109T. I'm not criticizing, but I am looking forward to the time when we have better information. Hopefully this happens by end of 2021, or my comparisons to NMA become more valid! :biggrin:

Couldn’t agree more, it’s all a bit “everyone says they want a new freighter” and not “here’s what the thing actually is” the biggest thing I got from the numbers that I put together was probably that 360t may well be required. The empty weight of these things is the real unknown(as it always is).


744SPX wrote:
My guess is that a 117T payload 778F will be at 778 passenger length. Any longer and I think it will start sacrificing payload. It would have plenty of volume at that length so I don't see any need to make it longer (and have a third fuselage length)

I think if they got to 360t MTOW then the 778x doesn’t exist as a pax variant. The 779x at 360t would have a pad and bags range of getting on for 8knm leaving no real room for the 8X

Fred

I don't know. I think if they went with 779 length, payload would drop to below 109T. Way too much extra structural weight.

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graceintheair
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Re: A350F vs 777XF vs 777ERSF

Tue Aug 10, 2021 1:58 am

VV wrote:
Okcflyer wrote:
VV wrote:
Why is the title "A350F vs 777XF vs 777ERSF"?

THe A350F has to be compared to the 777-8F.


Because the 77W is directly competitive.


Come on man, one is around since many years and the other has just been offered.
THere is a difference of ONE generation between the two.


But that doesn't mean it's not competitive. There are several airlines that can afford new airplanes but buy used ones because the economics still work out.
 
flipdewaf
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Re: A350F vs 777XF vs 777ERSF

Tue Aug 10, 2021 6:03 am

744SPX wrote:
flipdewaf wrote:
Revelation wrote:
For A350F payload we have Faury saying 90T+, you saying 95T, Reuters saying 109T. I'm not criticizing, but I am looking forward to the time when we have better information. Hopefully this happens by end of 2021, or my comparisons to NMA become more valid! :biggrin:

Couldn’t agree more, it’s all a bit “everyone says they want a new freighter” and not “here’s what the thing actually is” the biggest thing I got from the numbers that I put together was probably that 360t may well be required. The empty weight of these things is the real unknown(as it always is).


744SPX wrote:
My guess is that a 117T payload 778F will be at 778 passenger length. Any longer and I think it will start sacrificing payload. It would have plenty of volume at that length so I don't see any need to make it longer (and have a third fuselage length)

I think if they got to 360t MTOW then the 778x doesn’t exist as a pax variant. The 779x at 360t would have a pad and bags range of getting on for 8knm leaving no real room for the 8X

Fred

I don't know. I think if they went with 779 length, payload would drop to below 109T. Way too much extra structural weight.

Sent from my iPhone using Tapatalk

No, I meant the 778 would only exist in the freight version, the pax version isn’t needed if the 779x has 360t MTOW.

Fred


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morrisond
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Re: A350F vs 777XF vs 777ERSF

Wed Aug 11, 2021 9:12 pm

flipdewaf wrote:
My take on the freighters compared here is as below in the chart.
Image

if we assume the 4000nm trip is about 10hrs use and then assume that the fuel burns are associated with that usage as seen above then the A35F is about 6.1t/hr the ERSF 8.3 and the 777XF is 6.8.

at the current fuel price of $613 per ton and 10hrs per day utilisation over 22years the A35F costs 300m in fuel, the ERSF 409m and the 777XF 335m.

The ERSF would appear to be better on low utilisation models the 777XF would be best for the traditional 747 heavy lift scenario and the A35F on the scheduled low density package work as I have described here.

Fred


So in your opinion does the 350F need an MTOW and MZFW bump? it seems like it should be within the abilities of the design.
 
flipdewaf
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Re: A350F vs 777XF vs 777ERSF

Thu Aug 12, 2021 6:50 am

morrisond wrote:
flipdewaf wrote:
My take on the freighters compared here is as below in the chart.
Image

if we assume the 4000nm trip is about 10hrs use and then assume that the fuel burns are associated with that usage as seen above then the A35F is about 6.1t/hr the ERSF 8.3 and the 777XF is 6.8.

at the current fuel price of $613 per ton and 10hrs per day utilisation over 22years the A35F costs 300m in fuel, the ERSF 409m and the 777XF 335m.

The ERSF would appear to be better on low utilisation models the 777XF would be best for the traditional 747 heavy lift scenario and the A35F on the scheduled low density package work as I have described here.

Fred


So in your opinion does the 350F need an MTOW and MZFW bump? it seems like it should be within the abilities of the design.

If it’s within the capabilities of the already designed components then yes, if not then it depends on the figures that the market demands. I would see the MTOW increasing in line with the sunrise requirements (~323t) and the upping of the MZFW to 100 or 105t. In my estimates I have based the aero performance on the A351 so there is a little margin in there but probably not much.

Fred


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morrisond
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Re: A350F vs 777XF vs 777ERSF

Thu Aug 12, 2021 11:13 am

flipdewaf wrote:
morrisond wrote:
flipdewaf wrote:
My take on the freighters compared here is as below in the chart.
Image

if we assume the 4000nm trip is about 10hrs use and then assume that the fuel burns are associated with that usage as seen above then the A35F is about 6.1t/hr the ERSF 8.3 and the 777XF is 6.8.

at the current fuel price of $613 per ton and 10hrs per day utilisation over 22years the A35F costs 300m in fuel, the ERSF 409m and the 777XF 335m.

The ERSF would appear to be better on low utilisation models the 777XF would be best for the traditional 747 heavy lift scenario and the A35F on the scheduled low density package work as I have described here.

Fred


So in your opinion does the 350F need an MTOW and MZFW bump? it seems like it should be within the abilities of the design.

If it’s within the capabilities of the already designed components then yes, if not then it depends on the figures that the market demands. I would see the MTOW increasing in line with the sunrise requirements (~323t) and the upping of the MZFW to 100 or 105t. In my estimates I have based the aero performance on the A351 so there is a little margin in there but probably not much.

Fred


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I did not know about the 323T Sunrise requirements. That seems like an easy one as a minimum.

What length are you using for 350F? What happens if you use A351F and put effort into increasing it's abilities vs spending money on shortening it. That seems to be the Airbus way.

Reportedly XWB-97 have room for a thrust bump.

What happens when you bump MTOW up to say 340T with a thrust bump and use A351 Length? What does your model tell you? The weight penalty should not be that bad - maybe 5-8T for the extra length and some more strengthening.

With the numbers that are falling out of your model it just seems like an A350F will have really hard time with 777ERSF, and if it had more volume but maybe not quite as much capacity and still superior fuel burn that would allow it do well against 778XF.
 
flipdewaf
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Re: A350F vs 777XF vs 777ERSF

Thu Aug 12, 2021 6:39 pm

morrisond wrote:
flipdewaf wrote:
morrisond wrote:

So in your opinion does the 350F need an MTOW and MZFW bump? it seems like it should be within the abilities of the design.

If it’s within the capabilities of the already designed components then yes, if not then it depends on the figures that the market demands. I would see the MTOW increasing in line with the sunrise requirements (~323t) and the upping of the MZFW to 100 or 105t. In my estimates I have based the aero performance on the A351 so there is a little margin in there but probably not much.

Fred


Sent from my iPad using Tapatalk


I did not know about the 323T Sunrise requirements. That seems like an easy one as a minimum.

What length are you using for 350F? What happens if you use A351F and put effort into increasing it's abilities vs spending money on shortening it. That seems to be the Airbus way.

Reportedly XWB-97 have room for a thrust bump.

What happens when you bump MTOW up to say 340T with a thrust bump and use A351 Length? What does your model tell you? The weight penalty should not be that bad - maybe 5-8T for the extra length and some more strengthening.

With the numbers that are falling out of your model it just seems like an A350F will have really hard time with 777ERSF, and if it had more volume but maybe not quite as much capacity and still superior fuel burn that would allow it do well against 778XF.


The model I used is just based on a simple Breguet of the A35k specs with an estimation on the empty weight of 140t, I guess you would say the length I assumed was the same as the A35k, if you were to shorten the A35k for the -950F as has been mentioned then assessing that becomes a lot harder than just copying specs which is what I did for this. Likewise with the ERSF and 778X. We know the ERSF will have the same range factor as the 77W as it is geometrically identical and IAI mention both the empty weight and the payload, the rest just falls out of the Breguet equation.

Fred
 
morrisond
Topic Author
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Re: A350F vs 777XF vs 777ERSF

Fri Aug 13, 2021 2:14 am

flipdewaf wrote:
morrisond wrote:
flipdewaf wrote:
If it’s within the capabilities of the already designed components then yes, if not then it depends on the figures that the market demands. I would see the MTOW increasing in line with the sunrise requirements (~323t) and the upping of the MZFW to 100 or 105t. In my estimates I have based the aero performance on the A351 so there is a little margin in there but probably not much.

Fred


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I did not know about the 323T Sunrise requirements. That seems like an easy one as a minimum.

What length are you using for 350F? What happens if you use A351F and put effort into increasing it's abilities vs spending money on shortening it. That seems to be the Airbus way.

Reportedly XWB-97 have room for a thrust bump.

What happens when you bump MTOW up to say 340T with a thrust bump and use A351 Length? What does your model tell you? The weight penalty should not be that bad - maybe 5-8T for the extra length and some more strengthening.

With the numbers that are falling out of your model it just seems like an A350F will have really hard time with 777ERSF, and if it had more volume but maybe not quite as much capacity and still superior fuel burn that would allow it do well against 778XF.


The model I used is just based on a simple Breguet of the A35k specs with an estimation on the empty weight of 140t, I guess you would say the length I assumed was the same as the A35k, if you were to shorten the A35k for the -950F as has been mentioned then assessing that becomes a lot harder than just copying specs which is what I did for this. Likewise with the ERSF and 778X. We know the ERSF will have the same range factor as the 77W as it is geometrically identical and IAI mention both the empty weight and the payload, the rest just falls out of the Breguet equation.

Fred


Interesting - I like the idea of an 351F a lot better than an A350-950. From the articles the 950 apparently has a capacity of about 109T. Then yours at 95T in a longer length makes sense.

Say 5T extra for a bump in MTOW from 319T to 240 T and that would capacity right about 110-111T for 351 length - about perfect and something more than 777ERSF with a lot better fuel burn. That might have a market.

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