We know what the possible A350F specs are. Lets try and not make this an A v B thing. This is a thread to discuss a potential new model which should be fun. There may not be a lot of new metal for a long time.

The following is all my opinion. I think the A350F and potential 777XF should both sell hundred's of frames each and will define their own niche.

The only reason I am referencing the A350F is to help frame what kind of increases in things like MLW are possible.

Here is a reference for where I got the A350F info. https://aircraft.airbus.com/en/aircraft ... -freighter

Boeing 77F ACAP https://www.boeing.com/resources/boeing ... 2lr3er.pdf

Boeing 777-9 ACAP https://www.boeing.com/resources/boeing ... X_RevC.pdf

With a possible 777xf being launched next week one has to wonder how capable it is going to be.

There are rumours that it could have an MTOW of 365T based on what Boeing was talking about when they were thinking of launching an 777-10.

To match A350F belly capacity (40 LD3's) - you would have to cut down an 779 by 4.65M giving a length of approximately 72m.

The hardest thing to figure out is what will it's OEW and MLW weights be.

The 779 has an MLW of 266T. That grew by 15T over 77W. A350F is also about 14T over A351, at 250T.

77F has a MLW of 261T. Something around 275-280T doesn't seem impossible especially if they do bump the MTOW and beef up the structure.

What is the OEW weight? That is the hardest to figure out. A350F seems to be about 135T (250T MLW - 109T Cargo, minus Crew/minimum Fuel, 77F is 144T, 779 is rumoured to be somewhere between 180-195T.

To be able to lift 120T - 777xF OEW weight would have to be about 150-155T (as you have to allow some weight for Crew and diversion fuel and basics in the MlW - lets just call that 5T).

Does that seem reasonable or achievable? Even without increasing MTOW that would probably still allow for 77T of fuel (352-280-Reserves), which should give a good 10hour (5,000NM) of range.

Is it conceivable they shoot for higher than 280T MLW and take it to 365T MTOW to still allow 5,000 nm range?

What are the limits/issues on taking MLW past the 779 266T? Gear?

I believe that it will be about 150T OEW with a frame that’s the length of the 777-300ER and will lift 115 plus tonnes. That’s what I think. Looking forward to the launch

I take it the max. payload will be in the area of 115 - 125 tonnes. But being considerably heavier than the A350F the fuel consumption will also be proportionally higher, reducing potential max. range and raising operating i.e. tonne per kilometer costs. Plus it comes at a higher initial investment. Time will tell if it will be able to carry a 109 tonne load as far as an A350F. All assumptions thus far, all we can base this on is on the respective passenger versions until we have detailed specs

If they keep it at 778 length, they will have no problem with 120t at 5000nmi. They stretch it by 13' to 773 length and it will cost them. I don't see how the extra space would be worth the extra OEW. 12-15t (I'm guessing) for that kind of a stretch, and that's going to come right off max payload. To compete best with the A350 it should be focusing on max payload rather than max volume.

I mean jeez, the 778 is already a 20' stretch over the 772.

Heavierthanair wrote:

I take it the max. payload will be in the area of 115 - 125 tonnes. But being considerably heavier than the A350F the fuel consumption will also be proportionally higher, reducing potential max. range and raising operating i.e. tonne per kilometer costs. Plus it comes at a higher initial investment. Time will tell if it will be able to carry a 109 tonne load as far as an A350F. All assumptions thus far, all we can base this on is on the respective passenger versions until we have detailed specs

It has a bigger wing and more efficient engines - the fuel burn my not be hugely different, and if it lifts more Tonnes - the Tonne per kilometer could be better.

We have no idea what the actual transaction prices are. All we think we know is that the A350 is expensive to build. The 777X may not be as expensive to build and hence why it is so much heavier - as its probably using heavier but less expensive materials and the new wing factory could have removed a lot of labour costs as it is so automated.

744SPX wrote:

If they keep it at 778 length, they will have no problem with 120t at 5000nmi. They stretch it by 13' to 773 length and it will cost them. I don't see how the extra space would be worth the extra OEW. 12-15t (I'm guessing) for that kind of a stretch, and that's going to come right off max payload. To compete best with the A350 it should be focusing on max payload rather than max volume.

I mean jeez, the 778 is already a 20' stretch over the 772.

Yes - I agree that will be it's niche - MAX payload and density.

At somewhere around 72-73M you should be able to get 33 pallets up top (vs 34 for 748F) and 16 in the belly (vs 12 for 748F).

778 Length (70M) puts you at about 31 up top and 14 in the belly - almost the same as 748F - however I doubt they can get to 132 of lift like 748F.

The most basic of problems is that we don’t know which frame it will be based on or, indeed, if they’re going to opt for a “-8,5” length. However, with a much heavier frame they need a considerable volume and payload delta to the A350F, so with that in mind I’d inclined to go for the -9. Payload will need to be in the 120-125 tons bracket, so we can start calculating back from that

It might come out with an OEW of 160-165 tons. 120 tons of payload and 5 tons minimum fuel would require a MZFW of 275-280 tons and a MLW of 280-285 tons. It should be able to go for 11 hours / 5000NM at MZFW, which is around 80 tons of fuel and equals a TOW of 360-365 tons. Which are all big numbers, and I’m not sure (for any number of reasons) they are realistic.

For a -8 based solution, reduce OEW, MZFW and MTOW by 10 tons, keeping max payload at 120-125 tons but with 4 fewer positions on the main-deck. While that presents a sizeable max payload advantage over the A350F, volume wise there’s not much daylight between them, and with a heavier frame and all the costs that comes with that, it’s probably not that competitive. The numbers seem more achievable though.

For a “-8.5" everything would be somewhere in the middle of the two, and that might actually be the sweet spot.

Not an easy nut to crack.

B777LRF wrote:

The most basic of problems is that we don’t know which frame it will be based on or, indeed, if they’re going to opt for a “-8,5” length. However, with a much heavier frame they need a considerable volume and payload delta to the A350F, so with that in mind I’d inclined to go for the -9. Payload will need to be in the 120-125 tons bracket, so we can start calculating back from that

It might come out with an OEW of 160-165 tons. 120 tons of payload and 5 tons minimum fuel would require a MZFW of 275-280 tons and a MLW of 280-285 tons. It should be able to go for 11 hours / 5000NM at MZFW, which is around 80 tons of fuel and equals a TOW of 360-365 tons. Which are all big numbers, and I’m not sure (for any number of reasons) they are realistic.

For a -8 based solution, reduce OEW, MZFW and MTOW by 10 tons, keeping max payload at 120-125 tons but with 4 fewer positions on the main-deck. While that presents a sizeable max payload advantage over the A350F, volume wise there’s not much daylight between them, and with a heavier frame and all the costs that comes with that, it’s probably not that competitive. The numbers seem more achievable though.

For a “-8.5" everything would be somewhere in the middle of the two, and that might actually be the sweet spot.

Not an easy nut to crack.

I like your numbers.

I think it basically pencils out that if they bump the MTOW they will do the 779 length. No bump and then it will basically be A350F sized.

Even an 72-73M 77xF will give you about the same Pallet capacity (by volume) as 748F and if your numbers are right at MTOW of 365T they might approach the lift of an 748F at over 130T.

Has it not been mentioned by Boeing as an 748F replacement?

morrisond wrote:

Heavierthanair wrote:

I take it the max. payload will be in the area of 115 - 125 tonnes. But being considerably heavier than the A350F the fuel consumption will also be proportionally higher, reducing potential max. range and raising operating i.e. tonne per kilometer costs. Plus it comes at a higher initial investment. Time will tell if it will be able to carry a 109 tonne load as far as an A350F. All assumptions thus far, all we can base this on is on the respective passenger versions until we have detailed specs

It has a bigger wing and more efficient engines - the fuel burn my not be hugely different, and if it lifts more Tonnes - the Tonne per kilometer could be better.

We have no idea what the actual transaction prices are. All we think we know is that the A350 is expensive to build. The 777X may not be as expensive to build and hence why it is so much heavier - as its probably using heavier but less expensive materials and the new wing factory could have removed a lot of labour costs as it is so automated.

Whilst it may be more expensive to have the lighter materials it doesn’t then hold true that because it’s heavier it indicates less expensive. The 777X is heavier because it’s bigger, there may be some other factors but those are just noise.

The cost of the airframe is driven primarily by the weight and the manufacturing rate. If an aircraft (or any other product for that matter) has common parts the particular parts have a cost associated with the manufacturing rate of that part, likewise for low rate parts. This is really where the 35k suffers and the 789 and 10 shine.

The bulk of the performance is relatively easy to model/calculate/estimate however there is an anomaly in the 777 lineup and depending on how that turns out will make a big difference as to how the 77XF performs.

The anomaly is the weight of the 777f. We would normally expect that the deletion of the pax cabin and associated ancillary equipment as well as the window belt and safety equipment to give a significant reduction in the empty weight of the aircraft. For the 777f we would expect this weight change to be much higher than it is suggesting that there were structural changes required which normally aren’t. I think it’s reasonable to assume these could be to do with floor strengthening as the original 777 floor was not great for the high loading required for a freighter. How well the 77XF handles such changes may determine the overall empty weight and therefore overall performance.

The empty weight estimates I use have it 156-171t based on the above uncertainty.

Fred


Sent from my iPad using Tapatalk

flipdewaf wrote:

morrisond wrote:

Heavierthanair wrote:

I take it the max. payload will be in the area of 115 - 125 tonnes. But being considerably heavier than the A350F the fuel consumption will also be proportionally higher, reducing potential max. range and raising operating i.e. tonne per kilometer costs. Plus it comes at a higher initial investment. Time will tell if it will be able to carry a 109 tonne load as far as an A350F. All assumptions thus far, all we can base this on is on the respective passenger versions until we have detailed specs

It has a bigger wing and more efficient engines - the fuel burn my not be hugely different, and if it lifts more Tonnes - the Tonne per kilometer could be better.

We have no idea what the actual transaction prices are. All we think we know is that the A350 is expensive to build. The 777X may not be as expensive to build and hence why it is so much heavier - as its probably using heavier but less expensive materials and the new wing factory could have removed a lot of labour costs as it is so automated.

Whilst it may be more expensive to have the lighter materials it doesn’t then hold true that because it’s heavier it indicates less expensive. The 777X is heavier because it’s bigger, there may be some other factors but those are just noise.

The cost of the airframe is driven primarily by the weight and the manufacturing rate. If an aircraft (or any other product for that matter) has common parts the particular parts have a cost associated with the manufacturing rate of that part, likewise for low rate parts. This is really where the 35k suffers and the 789 and 10 shine.

The bulk of the performance is relatively easy to model/calculate/estimate however there is an anomaly in the 777 lineup and depending on how that turns out will make a big difference as to how the 77XF performs.

The anomaly is the weight of the 777f. We would normally expect that the deletion of the pax cabin and associated ancillary equipment as well as the window belt and safety equipment to give a significant reduction in the empty weight of the aircraft. For the 777f we would expect this weight change to be much higher than it is suggesting that there were structural changes required which normally aren’t. I think it’s reasonable to assume these could be to do with floor strengthening as the original 777 floor was not great for the high loading required for a freighter. How well the 77XF handles such changes may determine the overall empty weight and therefore overall performance.

The empty weight estimates I use have it 156-171t based on the above uncertainty.

Fred


Sent from my iPad using Tapatalk

Good points on manufacturing - and the big unknown is labour hours. That new wing could be relatively inexpensive to build given how automated it is.

What is the range of what you think it might be able to lift and at what MTOW?

You would have to imagine, IF the 778 is still going to be built, this aircraft would essentially be the Freighter version of it.

No, I wouldn't have to imagine that. Do prospective large customers emphasize weight-carrying ability (freight density, or range), or volume capabilities?

morrisond wrote:

The 779 has an MLW of 266T. That grew by 15T over 77W. A350F is also about 14T over A351, at 250T.

77F has a MLW of 261T. Something around 275-280T doesn't seem impossible especially if they do bump the MTOW and beef up the structure.

What is the OEW weight? That is the hardest to figure out. A350F seems to be about 135T (250T MLW - 109T Cargo, minus Crew/minimum Fuel, 77F is 144T, 779 is rumoured to be somewhere between 180-195T.

We have been given a few data points here.

Leeham says the A350F OEW is 30 tonne below the A350-1000, that makes it around 125 tonnes.

“ the aircraft is shortened, a whopping 30t is removed from the empty weight of the A350-1000.”

From https://leehamnews.com/2021/11/11/airbu ... fications/

Airbus has said an OEW 37 tonnes lower than the 744F and 13 tonnes lighter than the 77F



From https://aircraft.airbus.com/en/a350f

The A35F must OWE to be in the range of 125-129 tonnes based off those figures, which puts MZFW at around 238 tonnes which is pretty close to what it is on the -1000.

For the 77F OWE I used the Polar payload of 105,233 kg ( https://www.polaraircargo.com/wp-conten ... 319-v2.pdf) and MZFW of 248115 kg, OWE of 142882 kg. That also fits with the A35F payload being 3 tonnes more than the 77F.

So in summary A350F
OEW 125-129,000 kg
MZFW 238,000 kg
Payload 109,000 kg
MLW 243,000 kg
MTOW 317,000 kg

Now for the 77XF starting at the 77F base (Polar)
OEW 143000 kg
MZFW 248,000 kg
Payload 105,000 kg
MLW 260,000 kg
MTOW 348,000 kg

Now for the 77XF at 125,000 kg of payload
OEW 163,000 kg
MZFW 288,000 kg
Payload 125,000 kg
MLW 294,000 kg
MTOW 351,000 kg

If the 77XF was increased to a MTOW of 360 tonnes, that puts it at a 43,000 kg (95,000 lb) higher MTOW.

Is this reasonable ?

The 744F to 748F saw an increase of around 20 tonnes of payload
744F 112,000 kg https://www.atlasair.com/wp-content/upl ... 012418.pdf
748F 132,000 kg https://www.atlasair.com/wp-content/upl ... 012418.pdf

A350F 77F 744F 748F 77XF
OEW 129 143 180 206 163
MZFW 238 248 293 338 288
Payload 109 105 112 132 125
MLW 243 260 302 346 294
MTOW 317 348 396 447 351

I think MTOW of the 77XF needs to increase a lot to have range with 125,000 kg payload.

I think the OEW will be around 155-160 tonnes with a payload max around 120 tonnes. It should out lift the A350F by 10-15 tonnes. As the wing is larger on the 777XF it should be more efficient at high payloads. As a result, the fuel burn difference should be fairly close.

The key metric in my mind should be fuel burn per ton of payload. Since I believe the 777XF will carry more payload than the A350F the fuel burn per ton of could well be in the advantage of the 777XF. It should be ideal for heavy freight from China to North America or Europe.

Bottom line: I think both air frames will sell and be competitive. I do not anticipate a significant difference in fuel burn per ton of payload. My guess is in this area the 777XF will have a slight advantage.

zeke wrote:

morrisond wrote:

The 779 has an MLW of 266T. That grew by 15T over 77W. A350F is also about 14T over A351, at 250T.

77F has a MLW of 261T. Something around 275-280T doesn't seem impossible especially if they do bump the MTOW and beef up the structure.

What is the OEW weight? That is the hardest to figure out. A350F seems to be about 135T (250T MLW - 109T Cargo, minus Crew/minimum Fuel, 77F is 144T, 779 is rumoured to be somewhere between 180-195T.

We have been given a few data points here.

Leeham says the A350F OEW is 30 tonne below the A350-1000, that makes it around 125 tonnes.

“ the aircraft is shortened, a whopping 30t is removed from the empty weight of the A350-1000.”

From https://leehamnews.com/2021/11/11/airbu ... fications/

Airbus has said an OEW 37 tonnes lower than the 744F and 13 tonnes lighter than the 77F



From https://aircraft.airbus.com/en/a350f

The A35F must OWE to be in the range of 125-129 tonnes based off those figures, which puts MZFW at around 238 tonnes which is pretty close to what it is on the -1000.

For the 77F OWE I used the Polar payload of 105,233 kg ( https://www.polaraircargo.com/wp-conten ... 319-v2.pdf) and MZFW of 248115 kg, OWE of 142882 kg. That also fits with the A35F payload being 3 tonnes more than the 77F.

So in summary A350F
OEW 125-129,000 kg
MZFW 238,000 kg
Payload 109,000 kg
MLW 243,000 kg
MTOW 317,000 kg

Now for the 77XF starting at the 77F base (Polar)
OEW 143000 kg
MZFW 248,000 kg
Payload 105,000 kg
MLW 260,000 kg
MTOW 348,000 kg

Now for the 77XF at 125,000 kg of payload
OEW 163,000 kg
MZFW 288,000 kg
Payload 125,000 kg
MLW 294,000 kg
MTOW 351,000 kg

If the 77XF was increased to a MTOW of 360 tonnes, that puts it at a 43,000 kg (95,000 lb) higher MTOW.

Is this reasonable ?

The 744F to 748F saw an increase of around 20 tonnes of payload
744F 112,000 kg https://www.atlasair.com/wp-content/upl ... 012418.pdf
748F 132,000 kg https://www.atlasair.com/wp-content/upl ... 012418.pdf

A350F 77F 744F 748F 77XF
OEW 129 143 180 206 163
MZFW 238 248 293 338 288
Payload 109 105 112 132 125
MLW 243 260 302 346 294
MTOW 317 348 396 447 351

I think MTOW of the 77XF needs to increase a lot to have range with 125,000 kg payload.

Those numbers look pretty good. I would agree it needs more MTOW.

One has to think that the gear and wingbox are sized for more as they did contemplate higher numbers for 777-10 at one point. It was either 360 or 365T in that Boeing powerpoint that has been linked many times.

I'll try to find it again.

What are the choices in length? 240', or 230' with another 15Klb or 7t of payload capacity from the savings of the weight of that 10' of fuselage.

Now that the 350F specs are fixed, Boeing will want to differentiate away from that zone. Similar to how they specified the 779 in relation to the 35k.

So bigger and more capable.

There is a market for both, but which is larger?

whether or not Boeing addresses MLG limitations is the key issue, the rest is prioritizing factors in optimization

the b772f certainly looks attractive given what's currently on the horizon in VLA freighters
paneling general | express + covid; lessors must be optimistic about their current 777 freighter fleets

One might consider looking through a carrier's lens. A carrier will view the b77xf and the a350f as a tool/asset that they will have to sweat/stress/manage4profit for ~34 years.., the ERSF for ~half that time. They are going to ideally want a 773 length freighter(common parking/loading) that approaches general cargo density. Aeronautical engineers are going to run a series of optimizations and argue for a reduced length. This would give carriers a three legged 777 utility stool; in which most would operate two variants.

Its going to be expensive and unsurprisingly the b772f has become comparatively attractive as the picture in the horizon unfolds. What is amusing is Anet's variation and boundary testing on the size of the market; we've gone from 'there can be only one' to 'exceeding a pragmatic market size'.

I think Boeing might have some challenges reaching the maximum weights estimated. MZFW can be traded off against MTOW, sacrificing range. But otherwise it’s tough number to raise, as it’s governed by the strength of the wiwgbox. Beefing up that structure is of course possible, but it increases the OEW and starts eating into the maximum payload.

MLW is a bit easier to deal with, essentially requiring a stronger gear and brakes. Which again increases the OEW, but it’s relatively easy compared to the MZFW.

The MTOW might actually be the biggest challenge. If memory serves me right the -300ER is already at the PCN limit, and it’s my impression the -8 and -9 will retain the more or less the same MTOW. Raising the MTOW from 350 tons to 365 tons would require larger tires and changes to the gear, which all adds to the OEW.

I don’t believe a 155T OEW, 350T MTOW -8F with a payload of 110 tons and a MZFW range of 5000NM is a viable proposition; range, volume and payload will be almost identical to the A350F, but with an aircraft that’s 15-20 tons heavier and requiring a MTOW that’s 35 tons more. That spells “stillborn” to me.

So with that in mind, Boeing do have some work cut out for them in order to create a much more capable platform in order to justify the large weight delta.

As for the market, the big orders are bound to come from the Big 3 integrators; Yellow, Purple and Brown. They like range, volume and low fuel burn - a fully loaded FX or DHL 777F or 747F bulks out way before reaching payload maximum. Would a large volume delta -9F solution be more attractive than a lighter and lower volume A350F? I don’t have a crystal ball that can answer that, but looking at the ordering history of Big 3 they are clearly much more into lighter, lower volume, longer range (777F) than high payload, high volume, shorter range (747-8F). Looking the the rear view mirror to gauge whether the next turn is to the left or wright is wrought with danger, and I for one wouldn’t care to guess which way the market will move.

What if they go in the other direction with a -9F or -10F, and go for maximum volume at lower densities? 250' or 260' length with a 365 MTOW and 120t payload and reduced range at full payload.

B777LRF wrote:

I think Boeing might have some challenges reaching the maximum weights estimated. MZFW can be traded off against MTOW, sacrificing range. But otherwise it’s tough number to raise, as it’s governed by the strength of the wiwgbox. Beefing up that structure is of course possible, but it increases the OEW and starts eating into the maximum payload.

MLW is a bit easier to deal with, essentially requiring a stronger gear and brakes. Which again increases the OEW, but it’s relatively easy compared to the MZFW.

The MTOW might actually be the biggest challenge. If memory serves me right the -300ER is already at the PCN limit, and it’s my impression the -8 and -9 will retain the more or less the same MTOW. Raising the MTOW from 350 tons to 365 tons would require larger tires and changes to the gear, which all adds to the OEW.

I don’t believe a 155T OEW, 350T MTOW -8F with a payload of 110 tons and a MZFW range of 5000NM is a viable proposition; range, volume and payload will be almost identical to the A350F, but with an aircraft that’s 15-20 tons heavier and requiring a MTOW that’s 35 tons more. That spells “stillborn” to me.

So with that in mind, Boeing do have some work cut out for them in order to create a much more capable platform in order to justify the large weight delta.

As for the market, the big orders are bound to come from the Big 3 integrators; Yellow, Purple and Brown. They like range, volume and low fuel burn - a fully loaded FX or DHL 777F or 747F bulks out way before reaching payload maximum. Would a large volume delta -9F solution be more attractive than a lighter and lower volume A350F? I don’t have a crystal ball that can answer that, but looking at the ordering history of Big 3 they are clearly much more into lighter, lower volume, longer range (777F) than high payload, high volume, shorter range (747-8F). Looking the the rear view mirror to gauge whether the next turn is to the left or wright is wrought with danger, and I for one wouldn’t care to guess which way the market will move.

According to the President of Subaru who builds the 777X Wingbox "notes that the aluminum/titanium wing box that the company produces for the 777-8 and -9 is considerably heavier than that it builds for the legacy 777 programme."

“The 777X will carry more people and have a greater payload,” he says. “While its center wing-box is of similar size to that of the 777-300ER it is heavier with more reinforcement in the wings.”

From this article. http://airsoc.com/articles/view/id/5c07 ... iency-cost

All the extra weight in the 777X must be coming from somewhere.

DenverTed wrote:

What if they go in the other direction with a -9F or -10F, and go for maximum volume at lower densities? 250' or 260' length with a 365 MTOW and 120t payload and reduced range at full payload.

I don't think it could have any meaningful range at that length and with 120t payload. At 229' (778 length), I think you could do 120-125 t at 5000 nmi.

I don't think they can go any longer than the -8X if they want to have a meaningful payload advantage over the A350 at similar range.

At -8X length you effectively get a 1-for-1 744ER replacement both in terms of max payload, cargo volume, and range. Any longer (773 length or more) and you will be sacrificing payload, and even then you can only use the extra volume by flying almost exclusively with low density cargo. No way can you guarantee every flight will be maxed out on volume, and so you are flying dead weight. It will be easier to max out volume and maximize revenue with the 229' version.

744SPX wrote:

DenverTed wrote:

What if they go in the other direction with a -9F or -10F, and go for maximum volume at lower densities? 250' or 260' length with a 365 MTOW and 120t payload and reduced range at full payload.

I don't think it could have any meaningful range at that length and with 120t payload. At 229' (778 length), I think you could do 120-125 t at 5000 nmi.

I don't think they can go any longer than the -8X if they want to have a meaningful payload advantage over the A350 at similar range.

At -8X length you effectively get a 1-for-1 744ER replacement both in terms of max payload, cargo volume, and range. Any longer (773 length or more) and you will be sacrificing payload, and even then you can only use the extra volume by flying almost exclusively with low density cargo. No way can you guarantee every flight will be maxed out on volume, and so you are flying dead weight. It will be easier to max out volume and maximize revenue with the 229' version.

I assume a main deck pallet is about 10'. Adding 10' of fuselage is about 15,000lb, if that is fuel that can't be carried, that reduces range by 600 miles. So for 120t payload, 230' does 5,000nm, 240' does 4,400nm, 250' does 3,800, and 260' does 3,200.

morrisond wrote:

All the extra weight in the 777X must be coming from somewhere.

Longer wing. The maximum loads carried in the wings fundamentally scale with (span^2 * MZFW) which means a 779x wing is dealing with approximately 30% higher loads than a 77W.

Fred


Sent from my iPhone using Tapatalk

It is really interesting to see what Boeing is aiming for, a very heavy lifter (max payload) or a very large lifter (max volume) or something in between. What we know is, the 350F can no lift very heavy nor very much volume but it is really good overall. So if you need more payload or volume there are other options but if you just need something that is good enough for most missions it is the perfect aircraft.

Could be a bit similar to what 787 is in the pax market. It excells through its massive flexibility. Long flights, short flights, high densitiy cabin, low densitiy cabin, it is always a viable options. Yes if you need more payload or more volume (more seats) there are other options, but it is still the best option out there if you need a WB aircraft.

Now it is up to Boeing and their customers to find a solution where to place the 777XF in the market. I tend towards payload because the volume part can be filled from 300ER conversions.

FluidFlow wrote:

What we know is, the 350F can no lift very heavy nor very much volume but it is really good overall. So if you need more payload or volume there are other options but if you just need something that is good enough for most missions it is the perfect aircraft.

Is that an issue for most MD11F, 77F, or 744F flights ? It is not like the 748F demand was so great that it remained in production.

FluidFlow wrote:

Now it is up to Boeing and their customers to find a solution where to place the 777XF in the market. I tend towards payload because the volume part can be filled from 300ER conversions.

The physical specs is one part, the pricing specs are just as important. Where will the list price going to sit ? 420 million ?

744SPX wrote:

At -8X length you effectively get a 1-for-1 744ER replacement both in terms of max payload, cargo volume, and range.

That’s exactly what the A350F does, but at a considerably lower weight and therefore cost. Not a viable option IMHO

FluidFlow wrote:

What we know is, the 350F can no lift very heavy nor very much volume but it is really good overall. So if you need more payload or volume there are other options but if you just need something that is good enough for most missions it is the perfect aircraft.

Are you sure you’ve read the specs on the A350F correctly? It has roughly the same volume as a 747-400F and can lift 20ft pallets weighing up to 30 tons, which is also roughly the same as the 747-400F. It can lift 4 tons more than the 777F and has 11% more volume.

My feeling is that Boeing will target the B77XF to be closer to the B748F specs and therefore based on the -9 version.

Pricing wise the list prices of A350k and 777x hint that the 777xf is going to be more expensive. Same goes for production rate advantage…

AECM wrote:

My feeling is that Boeing will target the B77XF to be closer to the B748F specs and therefore based on the -9 version.

Agreed, that looks like the best option if they want to carve out a niche which isn’t already occupied by the much lighter A350F.

B777LRF wrote:

AECM wrote:

My feeling is that Boeing will target the B77XF to be closer to the B748F specs and therefore based on the -9 version.

Agreed, that looks like the best option if they want to carve out a niche which isn’t already occupied by the much lighter A350F.

It has already been said it will be based on the -8. For the -9 an even higher raise in MTOW would be needed to make good use of the extra volume.

The main aim for many posters in this discussion here, is to imagine specs that solidly beat the A350F.

I have no doubt that Boeing can design a capable 777XF. But there are some limitations or perhaps better consequences of trying to reach certain numbers in the specs.

If Boeing starts out with the 777-9, there is a frame with a payload of around 70 t. About the same as the 777-300ER and A350-1000.

Now the frame is 777-9 frame is shortened to reduce the OEW. Let us assume the same difference between the 777-9 and 777XF as between the 777-300ER and 777F.
If we assume the same MTOW as the 777-9, 351,5 t we should be now at a payload slightly above the 777F as in 103 + 4 = 107 t.
That I assume would combine with a bigger freight volume, slightly more range and less fuel burn than the 777F.

Any extra capabilities have to come out an MTOW increase, that should also result in extra structure and a increase on OEW.
So an MTOW increase to 365 t for example should not add the same amount of payload. 365 - 351,5 = 13,5 t.
The things that Boeing would need to do to increase the MTOW, would cut the payload increase so let us assume 10 t payload increase, coming to 117 T.

For me the first point would be the MLG. Even if the 777-9 has a new MLG, it has the same size as the 777-300ER MLG including the same size tires. The 777-300ER and 777-9 are at the upper limit of pavement loading, so the question is how much is it possible to increase the MTOW while keeping the same gear. There is also a limit to how much loading an area of pavement takes or for example bridges take.

Frames that have a higher MTOW than the 777-300ER went to increase the number of MLG to three A340-600 or four 747 and A380.

I would imagine that if Boeing wants to significantly up the MTOW, we could see for example a middle MLG, and than we could see numbers right past 365 t to 380+ t. A middle MLG with 2 or 4 tires would be near the wing box and would take space only from the belly cargo. It would take some changes to the wing box to make space for the gear, but that would mean structural changes in a limited area.

I imagine that there are enough reserves in the GE9X to produce the necessary thrust.

tvh wrote:

It has already been said it will be based on the -8. For the -9 an even higher raise in MTOW would be needed to make good use of the extra volume.

True, but that was before the A350F came along and torpedo’d that idea.

AECM wrote:

My feeling is that Boeing will target the B77XF to be closer to the B748F specs and therefore based on the -9 version.

The 779 main deck is about 483”/12.28m longer than the 77F. It should accommodate around 14 96x125 pallets below the deck and 35 contoured 96x125 pallets above deck, 49 total. The 748F is 12 below the deck and 34 96x125 contoured pallets above the deck, 46 total.

Even if it carried the same payload mass, the density would be lower than the 748F.

B777LRF wrote:

tvh wrote:

It has already been said it will be based on the -8. For the -9 an even higher raise in MTOW would be needed to make good use of the extra volume.

True, but that was before the A350F came along and torpedo’d that idea.

It didn’t torpedo the idea. It might have changed the length but it won’t take it to the -9 length. Still in between the two

flipdewaf wrote:

morrisond wrote:

All the extra weight in the 777X must be coming from somewhere.

Longer wing. The maximum loads carried in the wings fundamentally scale with (span^2 * MZFW) which means a 779x wing is dealing with approximately 30% higher loads than a 77W.

Fred


Sent from my iPhone using Tapatalk

Yes - got it - I was being a little facetious, the other poster was asking if the Wingbox was stronger - and yes it is - which is what may allow the much higher required MZFW weights.

What do you guess it could lift?

zeke wrote:

AECM wrote:

My feeling is that Boeing will target the B77XF to be closer to the B748F specs and therefore based on the -9 version.

The 779 main deck is about 483”/12.28m longer than the 77F. It should accommodate around 14 96x125 pallets below the deck and 35 contoured 96x125 pallets above deck, 49 total. The 748F is 12 below the deck and 34 96x125 contoured pallets above the deck, 46 total.

Even if it carried the same payload mass, the density would be lower than the 748F.

I don't think it will be a direct replacement but just feel that it will be marketed more towards the B748F. It has to fit somewhere in the market of B77F vs B773ERSF vs A350F vs B748F and i think it will be target more to the volume size. But lets see i could be totally wrong!

morrisond wrote:

flipdewaf wrote:

morrisond wrote:

All the extra weight in the 777X must be coming from somewhere.

Longer wing. The maximum loads carried in the wings fundamentally scale with (span^2 * MZFW) which means a 779x wing is dealing with approximately 30% higher loads than a 77W.

Fred


Sent from my iPhone using Tapatalk

Yes - got it - I was being a little facetious, the other poster was asking if the Wingbox was stronger - and yes it is - which is what may allow the much higher required MZFW weights.

What do you guess it could lift?

Whatever they decide it needs to lift...

They don't design it and then see what it can do, the design is based around the requirements.

Fred

Seems to me based on a lot of post, folks already know its limitations within a fixed range based on what we already know of the 777X, so can they really design based on requirements, or will the user just have to adjust their requirements to fit what the a/c can do, somewhat like abusing a widebody frame on a narrow body route because a perfect a/c does not exist?

The 777-10 specs are in an earlier version of this document from 2016 or 2017 if anyone can find it. I can't.

https://www.icao.int/SAM/Documents/2018 ... %20(ECosta).pdf

par13del wrote:

Seems to me based on a lot of post, folks already know its limitations within a fixed range based on what we already know of the 777X, so can they really design based on requirements, or will the user just have to adjust their requirements to fit what the a/c can do, somewhat like abusing a widebody frame on a narrow body route because a perfect a/c does not exist?

https://1drv.ms/x/s!AiAyKIX6pnf6ij6DcBY ... h?e=bg5WNr

This was my best guess on performance that I put in a previous thread. Basically still holds.

If we assume the MZFW is somewhere between 11t higher (as in the 77W->77F) to 17t higher than the pax version (as in the A35k->A35F) then we can make some assessments on max payload.

If we take a low ball figure of 156t for the OWE and a high figure of 17t higher for the MZFW (272t)then we have a payload figure of 116t. If we go for the other end of the spectrum of 171t OWE and a low MZFW figure (11t increase) of 266t then we get a max payload figure of 95t.

I'm inclined to believe it'll be the top end of that.

Fred

Opus99 wrote:

It didn’t torpedo the idea. It might have changed the length but it won’t take it to the -9 length. Still in between the two

Sorry if I wasn’t being clear. What I meant to say was, that the A350F looks to have effectively killed the prospect of Boeing basing their next freighter on the 777-8 fuselage. Which I guess is the reason it wasn’t launched at the DAS.

The -9 is, in my opinion, still very viable provided Boeing can get the numbers right. And that means around 36 main-deck positions, 120+ tons of payload and a MZFW range of 5000NM.

flipdewaf wrote:

par13del wrote:

Seems to me based on a lot of post, folks already know its limitations within a fixed range based on what we already know of the 777X, so can they really design based on requirements, or will the user just have to adjust their requirements to fit what the a/c can do, somewhat like abusing a widebody frame on a narrow body route because a perfect a/c does not exist?

https://1drv.ms/x/s!AiAyKIX6pnf6ij6DcBY ... h?e=bg5WNr

This was my best guess on performance that I put in a previous thread. Basically still holds.

If we assume the MZFW is somewhere between 11t higher (as in the 77W->77F) to 17t higher than the pax version (as in the A35k->A35F) then we can make some assessments on max payload.

If we take a low ball figure of 156t for the OWE and a high figure of 17t higher for the MZFW (272t)then we have a payload figure of 116t. If we go for the other end of the spectrum of 171t OWE and a low MZFW figure (11t increase) of 266t then we get a max payload figure of 95t.

I'm inclined to believe it'll be the top end of that.

Fred

So, in best case it’s going to carry 10% more payload with 20% higher OEW. Wonder what the fuel burn per ton will be…

flipdewaf wrote:

If we take a low ball figure of 156t for the OWE and a high figure of 17t higher for the MZFW (272t)then we have a payload figure of 116t. If we go for the other end of the spectrum of 171t OWE and a low MZFW figure (11t increase) of 266t then we get a max payload figure of 95t.

I posted above my reasoning behind an OEW of 143 tonnes for the 77F based upon polar airlines published information, I do not think it is reasonable to suggest an OEW of 156 tonnes unless the fuselage was only around 5 meters longer than the 77F.

The fuselage alone I would suggest would be around 2 tonnes per meter, with heavier engines and heavier wing.

JonesNL wrote:

flipdewaf wrote:

par13del wrote:

Seems to me based on a lot of post, folks already know its limitations within a fixed range based on what we already know of the 777X, so can they really design based on requirements, or will the user just have to adjust their requirements to fit what the a/c can do, somewhat like abusing a widebody frame on a narrow body route because a perfect a/c does not exist?

https://1drv.ms/x/s!AiAyKIX6pnf6ij6DcBY ... h?e=bg5WNr

This was my best guess on performance that I put in a previous thread. Basically still holds.

If we assume the MZFW is somewhere between 11t higher (as in the 77W->77F) to 17t higher than the pax version (as in the A35k->A35F) then we can make some assessments on max payload.

If we take a low ball figure of 156t for the OWE and a high figure of 17t higher for the MZFW (272t)then we have a payload figure of 116t. If we go for the other end of the spectrum of 171t OWE and a low MZFW figure (11t increase) of 266t then we get a max payload figure of 95t.

I'm inclined to believe it'll be the top end of that.

Fred

So, in best case it’s going to carry 10% more payload with 20% higher OEW. Wonder what the fuel burn per ton will be…

Its in a column at the end

Fred

zeke wrote:

flipdewaf wrote:

If we take a low ball figure of 156t for the OWE and a high figure of 17t higher for the MZFW (272t)then we have a payload figure of 116t. If we go for the other end of the spectrum of 171t OWE and a low MZFW figure (11t increase) of 266t then we get a max payload figure of 95t.

I posted above my reasoning behind an OEW of 143 tonnes for the 77F based upon polar airlines published information, I do not think it is reasonable to suggest an OEW of 156 tonnes unless the fuselage was only around 5 meters longer than the 77F.

The fuselage alone I would suggest would be around 2 tonnes per meter, with heavier engines and heavier wing.

As Fred pointed above - the 77F was heavier than need be as effectively I think they beefed up the floor - vs doing a custom design which could have been a lot lighter.

It will be interesting to side if they use 77F ribs or the expanded (heavy) 777X ribs that provide a little more volume - I'm not sure this will matter on the Freighter - other than it may allow less of a contour.

With 350F as competitor I think they basically will have to do a customized optimized fuselage.

If the 777-F and 777-200LR were about the same empty weight, the trade of removing windows for floor beams is about equal. The 777-9 empty is listed as 400Klb or 182t. If they go with a 230' fuselage, that shaves off 22' x 1500lb, leaving 367klb or 166t empty. At -300ER length to add another pallet, add 7t of fuselage and that goes up to 173t.
As pointed out in the above post, maybe lighter ribs at the window belt on the freighter.

Has B looked into adding a flip up nose like the 747Fs? Seems like that's a useful feature that will go away as the 747s do.

DenverTed wrote:

If the 777-F and 777-200LR were about the same empty weight, the trade of removing windows for floor beams is about equal. The 777-9 empty is listed as 400Klb or 182t. If they go with a 230' fuselage, that shaves off 22' x 1500lb, leaving 367klb or 166t empty. At -300ER length to add another pallet, add 7t of fuselage and that goes up to 173t.
As pointed out in the above post, maybe lighter ribs at the window belt on the freighter.

The 77F was heavier than optimal, due to the non-optimal floor design. If you look at at A359/A351 to A350F you can get a better idea of what the difference should be.

Or look at the 767-300ER vs F. The F was about 5T lighter or about 5%. It's not perfect - but the 77F should have been about 7T lighter than 77L. I guess when there was no competition there was no incentive to spend the money to make it better and it would have cannibalized the 748F more than it did.

Now that it does have competition I can't see them not optimizing it - but you never know.

Has Boeing published the final OEW weight on the 779? I was not aware of that.

If you are assuming starting with 779 182T OEW weight - 5% off that before you reduce for fuselage is 9T. That takes your 166T down to 157T - right in the ballpark of the other guesses.

Revo1059 wrote:

Has B looked into adding a flip up nose like the 747Fs? Seems like that's a useful feature that will go away as the 747s do.

The cockpit would have to be entirely relocated and is not feasible. The 747 was 100% designed for this feature which is where it gets it's unique shape. Future nose loading freighters could utilize a windowless cockpit located elsewhere in the cabin that utilizes cameras and other automation to facilitate the flight deck. While rerouting all of the systems on 777X flight deck isn't impossible it would be a massive undertaking that would be cost prohibitive while there are many young nose loading freighters currently operating.