Taxi645 wrote:

morrisond wrote:

I think I recall that the wing is good for 280T - I think that came from Lightsaber?

You have what the wingbox can bare and what provides efficiency at the higher end of TOW capability. It may be able to carry 280T, but doesn't mean you will be competitive against a 65m wing with significant winglets.

At a certain point, to fly efficient enough and thus be competitive you will need a larger wing(span).

I thought the gear was the weight limit? Specifically the pavement loading. The number seems right. I used to have a link on the 787 pavement load limit (I cannot find it).

As to being competitive, that will depend on the mission length and fleet composition (is a new type required?).

The competition goes on.

Lightsaber

lightsaber wrote:

Taxi645 wrote:

morrisond wrote:

I think I recall that the wing is good for 280T - I think that came from Lightsaber?

You have what the wingbox can bare and what provides efficiency at the higher end of TOW capability. It may be able to carry 280T, but doesn't mean you will be competitive against a 65m wing with significant winglets.

At a certain point, to fly efficient enough and thus be competitive you will need a larger wing(span).

I thought the gear was the weight limit? Specifically the pavement loading. The number seems right. I used to have a link on the 787 pavement load limit (I cannot find it).

As to being competitive, that will depend on the mission length and fleet composition (is a new type required?).

The competition goes on.

Lightsaber

Of course, however this HGW version is not being developed for the shorter missions. Otherwise they could've left as is.

It will be interesting to see how big they could make the wing. They could stretch out another 15ft and still fit in gates. They could use the 203ft design originally intended for the 787-9.

The plan was to make the 787-9 wing slightly bigger. But the weight growth of the platform put the plane up against the MTOW (landing gear based IIRC).

But putting on the wing extension would reduce the amount of fuel carried (more wing structure = less fuel if MTOW can’t increase) and thus not worth it.

There was a thread long ago talking about Boeing adding a center gear for MTOW increases, but I don’t think that went anywhere.

I think Boeing should concentrate on getting the 787 production and deliveries off the ground.

Revelation wrote:

ILikeTrains wrote:

I’m curious what more will need to be done to get the 787 up to 260T and beyond. I imagine thrust increases, and possibly increasing wing dimensions to keep T/O performance from getting out of hand.

I think an increase in wing dimensions would help, but of course it's very costly. It's interesting to me to see how 767 and A321 gained so much thrust over their life spans yet did not change the wing dimensions much if at all. It seems A321 re-designed the high lift devices a few times from -100 to XLR. I don't know if such an option would exist or be helpful for 787. One does also wonder if the original designers put any time into studying what they could do to help enable future HGW options.

Originally a wing extension was going to form part of the 787-9 equation. Boeing announced during the 787-9's development the 787-8's wing was good enough for the 9 and as such the 9 wing became a figment of history.

I suspect the original 9 wing could be a 'relatively' cheap upgrade for the nine. If so, a 787-9ER could have some interesting economics. It could also be the case the cross over in efficiency between the 787-9 and 787-9ER could be somewhere in the ~3000NM range rather than 5000-6000 for the 787-9 and A350. That could make things very interesting.

Time will tell!

So I have been working on some additional Modelling for the last few weeks before Christmas and looking at CASM rather than just fuel burn as I would normally. Inevitably there will be more assumptions but I figured this would be a good opportunity to make some suitable comparisons.

long story short: The charts show green where the aircraft has the lowest CASM of the selected and the blue is where it is within 5% of the lowest CASM available. The Range of the mission is shown along the top and the Additional Payload available to be carried is on the left in tons. Once the cost is calculated with the additional payload taken up (if possible) then the additional revenue of the payload is taken in to account ($0.2/t-nm) then the figure is divided by a figure that represents the number of seats (1.1seats/m^2).

The upper of the 2 charts shows the B781 with a 254t MTOW and the lower with 260t MTOW.



The interesting part is that the 781 MTOW increase only affects the sweet spot of the A359 when they get towards high additional cargo at 'low' range (sub 5000nm) and above 25t additional cargo availability. Its biggest effect is on the sweet spot of the 789, of course that is with the 789 at 254t MTOW so may not be relevant as this may too get the upgrade.

Fred

flipdewaf wrote:

So I have been working on some additional Modelling for the last few weeks before Christmas and looking at CASM rather than just fuel burn as I would normally. Inevitably there will be more assumptions but I figured this would be a good opportunity to make some suitable comparisons.

long story short: The charts show green where the aircraft has the lowest CASM of the selected and the blue is where it is within 5% of the lowest CASM available. The Range of the mission is shown along the top and the Additional Payload available to be carried is on the left in tons. Once the cost is calculated with the additional payload taken up (if possible) then the additional revenue of the payload is taken in to account ($0.2/t-nm) then the figure is divided by a figure that represents the number of seats (1.1seats/m^2).

The upper of the 2 charts shows the B781 with a 254t MTOW and the lower with 260t MTOW.



The interesting part is that the 781 MTOW increase only affects the sweet spot of the A359 when they get towards high additional cargo at 'low' range (sub 5000nm) and above 25t additional cargo availability. Its biggest effect is on the sweet spot of the 789, of course that is with the 789 at 254t MTOW so may not be relevant as this may too get the upgrade.

Fred

I couldn’t see the image inline in your post, I have seen it on the hitting website.

Can you confirm if you have MZFW and MLW limits in the model, not sure how a 787-10 can carry an additional 25 tonnes of payload.

zeke wrote:

flipdewaf wrote:

So I have been working on some additional Modelling for the last few weeks before Christmas and looking at CASM rather than just fuel burn as I would normally. Inevitably there will be more assumptions but I figured this would be a good opportunity to make some suitable comparisons.

long story short: The charts show green where the aircraft has the lowest CASM of the selected and the blue is where it is within 5% of the lowest CASM available. The Range of the mission is shown along the top and the Additional Payload available to be carried is on the left in tons. Once the cost is calculated with the additional payload taken up (if possible) then the additional revenue of the payload is taken in to account ($0.2/t-nm) then the figure is divided by a figure that represents the number of seats (1.1seats/m^2).

The upper of the 2 charts shows the B781 with a 254t MTOW and the lower with 260t MTOW.



The interesting part is that the 781 MTOW increase only affects the sweet spot of the A359 when they get towards high additional cargo at 'low' range (sub 5000nm) and above 25t additional cargo availability. Its biggest effect is on the sweet spot of the 789, of course that is with the 789 at 254t MTOW so may not be relevant as this may too get the upgrade.

Fred

I couldn’t see the image inline in your post, I have seen it on the hitting website.

Can you confirm if you have MZFW and MLW limits in the model, not sure how a 787-10 can carry an additional 25 tonnes of payload.

So it never takes more than ~21. The model has an available amount of cargo to be taken. At 25 t of cargo available the 781 only takes advantage of the offsetting effect of 21t, (at low ranges) whereas an A359 would be able to take more and have a higher offset. At 12t of additional cargo at low range they would have the same total offset although different per seat still.

Hope that makes sense.

Fred


Sent from my iPad using Tapatalk

ILikeTrains wrote:

It will be interesting to see how big they could make the wing. They could stretch out another 15ft and still fit in gates. They could use the 203ft design originally intended for the 787-9.

Why not use the folding wingtip technology developed for the 777X? If a 777 can be rewinged with 787 wing technology and folding wingtips, why not a 787?

Opus99 wrote:

flipdewaf wrote:

So I have been working on some additional Modelling for the last few weeks before Christmas and looking at CASM rather than just fuel burn as I would normally. Inevitably there will be more assumptions but I figured this would be a good opportunity to make some suitable comparisons.

long story short: The charts show green where the aircraft has the lowest CASM of the selected and the blue is where it is within 5% of the lowest CASM available. The Range of the mission is shown along the top and the Additional Payload available to be carried is on the left in tons. Once the cost is calculated with the additional payload taken up (if possible) then the additional revenue of the payload is taken in to account ($0.2/t-nm) then the figure is divided by a figure that represents the number of seats (1.1seats/m^2).

The upper of the 2 charts shows the B781 with a 254t MTOW and the lower with 260t MTOW.



The interesting part is that the 781 MTOW increase only affects the sweet spot of the A359 when they get towards high additional cargo at 'low' range (sub 5000nm) and above 25t additional cargo availability. Its biggest effect is on the sweet spot of the 789, of course that is with the 789 at 254t MTOW so may not be relevant as this may too get the upgrade.

Fred

This is great Fred. I understand some parts of it and some parts I don’t.

But let me ask this based off your own analysis. What does this mean for the prospects of the 787-10? Does it for example question the need for United to have 350s or can this still not do the job. That’s really my main question

Totally depends if the MTOW increase is brought across to the 789. The increase in MTOW for the 781 brings the sweet spot closer to the 789, the A359 still lies higher than that.

Fred


Sent from my iPad using Tapatalk

Another article about the prospects of the HGW 78J and 789 which could become a real project sunrise option with 800nm more range.

https://www.aviacionline.com/2022/01/bo ... er-family/

lightsaber wrote:

Taxi645 wrote:

morrisond wrote:

I think I recall that the wing is good for 280T - I think that came from Lightsaber?

You have what the wingbox can bare and what provides efficiency at the higher end of TOW capability. It may be able to carry 280T, but doesn't mean you will be competitive against a 65m wing with significant winglets.

At a certain point, to fly efficient enough and thus be competitive you will need a larger wing(span).

I thought the gear was the weight limit? Specifically the pavement loading. The number seems right. I used to have a link on the 787 pavement load limit (I cannot find it).

As to being competitive, that will depend on the mission length and fleet composition (is a new type required?).

The competition goes on.

Lightsaber

I would think pavement loading can be addressed with a bigger tire

One obvious question is - how capable would a 260T 787-10 be with the mythical 2030 engines? How much better would those engines be? 10%? Assume no other changes.

Even if not a new engine - has enough time passed what GE9X tech could be moved over to these engines in terms of a PIP for Service entry by say 2025-2026 and what improvements could this bring? 3-5%? What does that do? Does it become capable enough that it becomes the preferred model?

I think the gains in engine performance are becoming much harder to achieve and getting 10% in 8 years is I suspect fantasy extrapolation of previous performance gains.

StTim wrote:

I think the gains in engine performance are becoming much harder to achieve and getting 10% in 8 years is I suspect fantasy extrapolation of previous performance gains.

How about adding something vs just being critical.

I did put put a question mark behind the 10. If you don't think 10% is possible - what do you think is possible? What do you think could be achieved with a clean sheet based off Ge9X or an Ultrafan? Or what PIP's are available in 3-4 years to upgrade the existing engines.

8 Years? Where do you get that from? 2030 would be a good 15 years since EIS of GenX or Trent 1000's.

The Ge9X got a 10% fuel burn improvement over GE90-115. The Entry into service between the two is about 15 years (the engines were done by then).

morrisond wrote:

StTim wrote:

I think the gains in engine performance are becoming much harder to achieve and getting 10% in 8 years is I suspect fantasy extrapolation of previous performance gains.

How about adding something vs just being critical.

I did put put a question mark behind the 10. If you don't think 10% is possible - what do you think is possible? What do you think could be achieved with a clean sheet based off Ge9X or an Ultrafan? Or what PIP's are available in 3-4 years to upgrade the existing engines.

8 Years? Where do you get that from? 2030 would be a good 15 years since EIS of GenX or Trent 1000's.

The Ge9X got a 10% fuel burn improvement over GE90-115. The Entry into service between the two is about 15 years (the engines were done by then).

How GE could acheive 10% in ten years:
1. 3.5: 1 GTF, about 6.5% fuel burn reduction
2. Higher match # high pressure compressor (needs better bearings and seals), about 1% fuel burn reduction
3. Fan improvements, about 0.2%(yes, just a fraction of a percent)
4. CMC inlet guide vanes to high turbine: 2.5% (s/b within 5 years, if not sooner)
5. CMC turbine stators, perhaps 0.5%
6. CMC combustor liners, perhaps 0.5%
7. Now what is really in question for within ten years, is CMC 2nd stage high turbine blades (about 2.5%), but due to the stresses, iffy. I do not consider 1st stage turbine blades possible within ten years, but that is just my opinion.
8. Improved compressor variable bleet (0.25% or so)
9. Improved variable turbine cooling (0.35% or so)

They also need to add to the 787 the GE9x technologies (already developed):
10. Variable turbine cooling, 2.7% or so
11. Improved cooling loops 0.75% or so
12. CMC coated combustor liner 0.2%
13. Fan blade tech (needs a new design to change bypass ratio) 0.5%

The could also do conter-rotation,but GE has chosen a different tech path and this might be a bridge too far in terms of bearing and seal speeds.

Lightsaber

morrisond wrote:

StTim wrote:

I think the gains in engine performance are becoming much harder to achieve and getting 10% in 8 years is I suspect fantasy extrapolation of previous performance gains.

How about adding something vs just being critical.

I did put put a question mark behind the 10. If you don't think 10% is possible - what do you think is possible? What do you think could be achieved with a clean sheet based off Ge9X or an Ultrafan? Or what PIP's are available in 3-4 years to upgrade the existing engines.

8 Years? Where do you get that from? 2030 would be a good 15 years since EIS of GenX or Trent 1000's.

The Ge9X got a 10% fuel burn improvement over GE90-115. The Entry into service between the two is about 15 years (the engines were done by then).

The answer is I don't know how much but I do know that we are really pushing the envelope for new gains. Each new engine we have is bigger and heavier to get those gains. Also from my dim and distant Mechanical engineering degree I remember doing the maths about efficiency of perfect cycles - including open cycle gas turbine. Each step we take to get to those "perfect" cycle figures becomes harder and harder.

This is why when you look at what RR is doing it is about the gearbox (I know it isn't the only thing it is doing) to improve propulsion efficiency of the fan. CFM with the rise look to be going for a form of open rotor although they won't call it a turbo prop due to USA customer perceptions of turbo props.

So all I am saying is that gains are getting harder and harder to get and more and more expensive to do so. Thus I do not see past performance as an indicator of future performance when it comes to engines.


I suspect there are very few on here who are party to the figure but also where we have had an average of 1% per year (by most peoples view on here) that does not mean 10% over 10 years. It is actually

lightsaber wrote:

How GE could acheive 10% in ten years:
1. 3.5: 1 GTF, about 6.5% fuel burn reduction
2. Higher match # high pressure compressor (needs better bearings and seals), about 1% fuel burn reduction
3. Fan improvements, about 0.2%(yes, just a fraction of a percent)
4. CMC inlet guide vanes to high turbine: 2.5% (s/b within 5 years, if not sooner)
5. CMC turbine stators, perhaps 0.5%
6. CMC combustor liners, perhaps 0.5%
7. Now what is really in question for within ten years, is CMC 2nd stage high turbine blades (about 2.5%), but due to the stresses, iffy. I do not consider 1st stage turbine blades possible within ten years, but that is just my opinion.
8. Improved compressor variable bleet (0.25% or so)
9. Improved variable turbine cooling (0.35% or so)

They also need to add to the 787 the GE9x technologies (already developed):
10. Variable turbine cooling, 2.7% or so
11. Improved cooling loops 0.75% or so
12. CMC coated combustor liner 0.2%
13. Fan blade tech (needs a new design to change bypass ratio) 0.5%

The could also do conter-rotation,but GE has chosen a different tech path and this might be a bridge too far in terms of bearing and seal speeds.

Lightsaber

Yes, and to do anything but the low hanging fruit they will need a huge financial investment to make it happen. This won't happen any time soon since the long haul sector of the airline industry is sucking wind (see what I did there?) for the last two years and will need several years of positive cash flow before they decide to replace the current generation engines.

I have seen nothing much in the past year or so about RR on the 787.

Can anyone update on whether the known issues are fully resolved? And, if so, does RR have any plans to remain competitive against the possible GE developments?

lightsaber wrote:

morrisond wrote:

StTim wrote:

I think the gains in engine performance are becoming much harder to achieve and getting 10% in 8 years is I suspect fantasy extrapolation of previous performance gains.

How about adding something vs just being critical.

I did put put a question mark behind the 10. If you don't think 10% is possible - what do you think is possible? What do you think could be achieved with a clean sheet based off Ge9X or an Ultrafan? Or what PIP's are available in 3-4 years to upgrade the existing engines.

8 Years? Where do you get that from? 2030 would be a good 15 years since EIS of GenX or Trent 1000's.

The Ge9X got a 10% fuel burn improvement over GE90-115. The Entry into service between the two is about 15 years (the engines were done by then).

How GE could acheive 10% in ten years:
1. 3.5: 1 GTF, about 6.5% fuel burn reduction
2. Higher match # high pressure compressor (needs better bearings and seals), about 1% fuel burn reduction
3. Fan improvements, about 0.2%(yes, just a fraction of a percent)
4. CMC inlet guide vanes to high turbine: 2.5% (s/b within 5 years, if not sooner)
5. CMC turbine stators, perhaps 0.5%
6. CMC combustor liners, perhaps 0.5%
7. Now what is really in question for within ten years, is CMC 2nd stage high turbine blades (about 2.5%), but due to the stresses, iffy. I do not consider 1st stage turbine blades possible within ten years, but that is just my opinion.
8. Improved compressor variable bleet (0.25% or so)
9. Improved variable turbine cooling (0.35% or so)

They also need to add to the 787 the GE9x technologies (already developed):
10. Variable turbine cooling, 2.7% or so
11. Improved cooling loops 0.75% or so
12. CMC coated combustor liner 0.2%
13. Fan blade tech (needs a new design to change bypass ratio) 0.5%

The could also do conter-rotation,but GE has chosen a different tech path and this might be a bridge too far in terms of bearing and seal speeds.

Lightsaber

Thank you for the fantastic answer as always.

So 3-4% is achievable on GeNX as a PIP? When would this be deliverable do you believe?

Other than that are you basically saying that no need to do a Custom Ge9X for 787 - just wait until GE can do a GTF version which I'm guessing would be more like 2035? And is that 10% on top of Ge9X? I know it's not additive but call it 13-15% or so over a GeNX by 2035?

flyingclrs727 wrote:

ILikeTrains wrote:

It will be interesting to see how big they could make the wing. They could stretch out another 15ft and still fit in gates. They could use the 203ft design originally intended for the 787-9.

Why not use the folding wingtip technology developed for the 777X? If a 777 can be rewinged with 787 wing technology and folding wingtips, why not a 787?

Folding wingtip technology is heavy. They won’t use it if there’s no real need. When designing the 777X they decided to add some extra weight (folding wing tips) to make the aircraft able to carry the more efficient (= wider) wing. But I don’t think they would add this kind of extra weight to a 787.

ben7x wrote:

flyingclrs727 wrote:

ILikeTrains wrote:

It will be interesting to see how big they could make the wing. They could stretch out another 15ft and still fit in gates. They could use the 203ft design originally intended for the 787-9.

Why not use the folding wingtip technology developed for the 777X? If a 777 can be rewinged with 787 wing technology and folding wingtips, why not a 787?

Folding wingtip technology is heavy. They won’t use it if there’s no real need. When designing the 777X they decided to add some extra weight (folding wing tips) to make the aircraft able to carry the more efficient (= wider) wing. But I don’t think they would add this kind of extra weight to a 787.

Especially since as mentioned the 787 still has room to play with before it would move up a gate classification. And to give the 787 folding wingtips that would knock it down a classification would require an entirely redesigned wing.

ben7x wrote:

flyingclrs727 wrote:

ILikeTrains wrote:

It will be interesting to see how big they could make the wing. They could stretch out another 15ft and still fit in gates. They could use the 203ft design originally intended for the 787-9.

Why not use the folding wingtip technology developed for the 777X? If a 777 can be rewinged with 787 wing technology and folding wingtips, why not a 787?

Folding wingtip technology is heavy. They won’t use it if there’s no real need. When designing the 777X they decided to add some extra weight (folding wing tips) to make the aircraft able to carry the more efficient (= wider) wing. But I don’t think they would add this kind of extra weight to a 787.

Yes - probably not much need.

Bump the MTOW and PIP the engines and the 789/781 could become very capable. Relatively low cost and could drive new sales.

morrisond wrote:

ben7x wrote:

flyingclrs727 wrote:

Why not use the folding wingtip technology developed for the 777X? If a 777 can be rewinged with 787 wing technology and folding wingtips, why not a 787?

Folding wingtip technology is heavy. They won’t use it if there’s no real need. When designing the 777X they decided to add some extra weight (folding wing tips) to make the aircraft able to carry the more efficient (= wider) wing. But I don’t think they would add this kind of extra weight to a 787.

Yes - probably not much need.

Bump the MTOW and PIP the engines and the 789/781 could become very capable. Relatively low cost and could drive new sales.

Absolutely. A higher MTOW 787-9 could be a big deal for EK, QF, UA, NZ, and others. Would likely spell the end of the 778, but I doubt that aircraft had any chance at mass-market success anyway.

A more capable 787-10 could also be the perfect 772 replacement for AA and UA. I can see both variants being big hits especially as the 777/A330 replacement cycle ramps up.

I can’t help but wonder if any efficiency gains that Boeing/GE can find will be applied to the 788. We haven’t heard much about that variant since Boeing said AA’s frames would feature more commonality with the 789.

Revelation wrote:

Yes, and to do anything but the low hanging fruit they will need a huge financial investment to make it happen. This won't happen any time soon since the long haul sector of the airline industry is sucking wind (see what I did there?) for the last two years and will need several years of positive cash flow before they decide to replace the current generation engines.

morrisond wrote:

Yes - probably not much need.

Bump the MTOW and PIP the engines and the 789/781 could become very capable. Relatively low cost and could drive new sales.

Problem is if you only do a 3-4% PIP and you competitor does a 8-10% GTF, you may have saved a lot of investment, but your sales will get a severe hit.

Taxi645 wrote:

Revelation wrote:

Yes, and to do anything but the low hanging fruit they will need a huge financial investment to make it happen. This won't happen any time soon since the long haul sector of the airline industry is sucking wind (see what I did there?) for the last two years and will need several years of positive cash flow before they decide to replace the current generation engines.

morrisond wrote:

Yes - probably not much need.

Bump the MTOW and PIP the engines and the 789/781 could become very capable. Relatively low cost and could drive new sales.

Problem is if you only do a 3-4% PIP and you competitor does a 8-10% GTF, you may have saved a lot of investment, but your sales will get a severe hit.

Good luck getting that within 10 years though. Read this thread viewtopic.php?t=1456349

and specifically this answer by Lightsaber. #20.

Quoting him:

"I wish the billions needed for new factories, development, and testing could be thrown around casually.

The iphone us a great example, in effect every other one is a PiP sold as the latest and greatest. But the next generation needs a gearbox factory setup for Aerospace practices and documentation (I believed Mitsubishi had so many issues with the MRJ due to thinking car manufacturing was good enough. Nope, there is a reason planes can be identified by s/n on which need an added inspection and which do not. If the paperwork doesn't outweigh the engine, it isn't ready to ship.

It takes 7 to 9 years to develop a new architecture engine once the concept has been completely proven in a prototype.

A great example is the Merlin engine of WW2, to manufacture in mass quantities, Ford had to tighten the tolerances to make truly interchangeable parts:
https://www.autoweek.com/car-life/class ... er-merlin/

"I replied loftily, 'I suppose that is because the drawing tolerances are too difficult for you, and you can't achieve the accuracy.'

"'On the contrary,' he replied, 'the tolerances are far too wide for us. We make motor cars far more accurately than this. Every part on our car engines has to be interchangeable with the same part on any other engine, and hence all parts have to be made with extreme accuracy, far closer than you use. That is the only way we can achieve mass production.'"
.(For the record, RR engines has 5% more horsepower, but took twice the labor hours of the Ford built engines that were not match fit. Packard had great engines with a camshaft built to spec except it wore down a little, which cost horsepower.)

All jet engine parts must be interchangeable. It takes years to do the calculations and prove out the manufacturing process. Today all engines must meet durability, thrust, and be completely interchangeable. If two engines come out if the factory with a 0.25% fuel burn difference, the customer will demand the higher fuel burn one be fixed. So there must be new processes developed to meet design.

I've been given hell for designing tight tolerance springs in an engine. Why? To meet the performance requirements for all manufacturing tolerances and worst case end of life wear, that was required, a bleed air regulator needed a $5 more expensive spring to ensure safe anti-icing (ensure enough flow) but when the engine was worn out (but still safe to fly) with worst case manufacturing tolerances, to prevent excess fuel burn, a very tight tolerance of spring was required.

While boring, this is the sort of stuff that must be analysed. I have found unstable control loops that were fine in the prototype, but fly that engine 30,000 FH and whoa, everything behaving loose creates a problem.

This is why even a PiP takes 3 or 4 years and several hundred million dollars. Design, analyze, test, and in parallel certify the production process. This is why the CFM-56 wasn't displaced quickly nor prior to it the JT8D.

Then you have to have certified maintenance, inspection, and some standard MRB repairs ready before EIS. e.g., The ultrafan needs a new fan ding repair process. That alone will take 5 years to develop. RR was beat up enough by testing parts in a low sulfur environment that failed early. Ironically, it doesn't matter where the sulfur came from considering the parts were downstream of the combustor. Pratt actually imports high sulfur fuel for testing new engines just to check this chemical behavior. (Yes, the messed up on seals at high relative veolicities, fixed).

The ultrafan will increase bearing and seal speeds. Pratt showed RR more testing on this is required. That is $250 million in testing and it is a big deal if a problem is found as some things the testing finds what the analysis missed (I alternate between the two roles, or did... Now I speak the language of the multiple teams).

The T1000 problems hurt RR sales and will cost RR 2.4 billion pounds. RR cannot afford the development costs of a new engine until the power by the hour revenue is rolling in and a bit of debt is paid off (my opinion, link on T1000 costs follows):
https://www.cnbc.com/2019/11/07/rolls-r ... ngine.html

I think RR designs excellent engines. Unfortunately, until fuel is back over $140/bbl, no one will develop a new widebody or new widebody engine, in my opinion.

Lightsaber"

Taxi645 wrote:

Problem is if you only do a 3-4% PIP and you competitor does a 8-10% GTF, you may have saved a lot of investment, but your sales will get a severe hit.

RR is part of the "industry sucking wind" reference. Consider the huge spend on T1000 and their reliance on power by the hour contracts that are big losers when much of world's wide bodies are not flying at all or flying reduced hours, then to do the GTF consider the man hours to move from prototype to production, and all the money for all the tooling that will need to be purchased.

( Note, I typed this before seeing the Lightsaber post that says the same thing far better than I did ).

Personally, while this MTOW bump looks to open up the envelope a bit for Boeing, I doubt it threatens the A350 enough for Airbus to push RR into producing an UltraFan for GTF any time soon.

lightsaber wrote:

How about adding something vs just being critical.

I did put put a question mark behind the 10. If you don't think 10% is possible - what do you think is possible? What do you think could be achieved with a clean sheet based off Ge9X or an Ultrafan? Or what PIP's are available in 3-4 years to upgrade the existing engines.

8 Years? Where do you get that from? 2030 would be a good 15 years since EIS of GenX or Trent 1000's.

The Ge9X got a 10% fuel burn improvement over GE90-115. The Entry into service between the two is about 15 years (the engines were done by then).
How GE could acheive 10% in ten years:
1. 3.5: 1 GTF, about 6.5% fuel burn reduction
2. Higher match # high pressure compressor (needs better bearings and seals), about 1% fuel burn reduction
3. Fan improvements, about 0.2%(yes, just a fraction of a percent)
4. CMC inlet guide vanes to high turbine: 2.5% (s/b within 5 years, if not sooner)
5. CMC turbine stators, perhaps 0.5%
6. CMC combustor liners, perhaps 0.5%
7. Now what is really in question for within ten years, is CMC 2nd stage high turbine blades (about 2.5%), but due to the stresses, iffy. I do not consider 1st stage turbine blades possible within ten years, but that is just my opinion.
8. Improved compressor variable bleet (0.25% or so)
9. Improved variable turbine cooling (0.35% or so)

They also need to add to the 787 the GE9x technologies (already developed):
10. Variable turbine cooling, 2.7% or so
11. Improved cooling loops 0.75% or so
12. CMC coated combustor liner 0.2%
13. Fan blade tech (needs a new design to change bypass ratio) 0.5%

The could also do conter-rotation,but GE has chosen a different tech path and this might be a bridge too far in terms of bearing and seal speeds.

Lightsaber

You need to be careful how to use these numbers. You can not add up percentages of indivudual components to get to a total improvement. Every change you make impacts the gain you can get on the subsequent improvement.

I have seen this kind of double counting in the past in the wind turbine projects we were working on. If you added up all the individual improvements we had on the technology roadmap, you got to 50% improvement of efficiency.
But the product on the market 10 years later is at best 20% more efficient and the bulk of that is being able to tailor blade length (rotor diameter) better to deployment conditions. Some of the technologies were different ways of getting the same result. And if you create a 10% improvement due to optimising rotor size, that 4% aerodynamic improvement planned due to improved design tools which better cater for the bending of the blade under load is suddenly no longer a 4% improvement but probably closer to 1-2% because you address inefficiencies in the rotor and they are now on a whole much smaller.

Is this HGW bump going to be new-build only or can existing frames be upgraded?

lightsaber wrote:

How GE could acheive 10% in ten years:
1. 3.5: 1 GTF, about 6.5% fuel burn reduction
2. Higher match # high pressure compressor (needs better bearings and seals), about 1% fuel burn reduction
3. Fan improvements, about 0.2%(yes, just a fraction of a percent)
4. CMC inlet guide vanes to high turbine: 2.5% (s/b within 5 years, if not sooner)
5. CMC turbine stators, perhaps 0.5%
6. CMC combustor liners, perhaps 0.5%
7. Now what is really in question for within ten years, is CMC 2nd stage high turbine blades (about 2.5%), but due to the stresses, iffy. I do not consider 1st stage turbine blades possible within ten years, but that is just my opinion.
8. Improved compressor variable bleet (0.25% or so)
9. Improved variable turbine cooling (0.35% or so)

They also need to add to the 787 the GE9x technologies (already developed):
10. Variable turbine cooling, 2.7% or so
11. Improved cooling loops 0.75% or so
12. CMC coated combustor liner 0.2%
13. Fan blade tech (needs a new design to change bypass ratio) 0.5%

The could also do conter-rotation,but GE has chosen a different tech path and this might be a bridge too far in terms of bearing and seal speeds.

Lightsaber

Thank you for the information, in particular the possible improvement by category. Yes, all these interact, so the total improvement is something less than the sum of the percents. Also, many improvements won't make the cut into a new PIP.

The serious hit to RR by the T1000 will make them quite cautious for a period, they wouldn't survive the next hit. Coupled with Power by the Hour revenues being in the tank, the Ultrafan will continue being researched, finding out the durability, performance, and design are quite mature. There may be a bonus 3 years here to mature the design before the decision to proceed.

That leaves GE as the only player that could proceed with a PIP, but why, better to go slower, do a lot of research to mature the PIPs.

Aviation development won't thaw out until deliveries are back healthy for 3-4 years to get the books sufficiently in the black.

The 787-10 will really kick the competition if it improves range by 10%

If even a PIP will cost a lot of money, is either GE or RR in a position to offer these at the moment? I know as fans we like to dream about what is possible, but realistically will GE Aviation be in a position to offer PIP's in the future?

JayinKitsap wrote:

Coupled with Power by the Hour revenues being in the tank.............

Perhaps a bit harsh.

RR PBTH plans have some core elements.

If a customer puts an engine into storage, there is a one off storage fee, and another when re-commissioned.

There is still a monthly fee while in storage, but much lower than if in use.

Also, the contract period extends by the length of the storage period. So a 12 year plan, engine in storage 2 years, becomes a 14 year plan.

The customer can opt to buy out, but that's close to the sum of the monthly payments for the entire contract period, which is why most customers, even if they part out a scrapped plane, find a temporary home for the engines for the remaining contract period, as we saw when SQ leased A380's were scrapped.

Customers taking delivery since COVID have entered into special arrangements, which may or may not include existing aircraft.

In contrast, how much do GE earn on stored engines?

lightsaber wrote:

I thought the gear was the weight limit? Specifically the pavement loading.

Exactly this.

Wiki has a list, which looks more-or-less reliable.
https://www.youtube.com/watch?v=VEuYn9_e1Ac
In terms of PCR, 787-9 (and J, as weights/dimensions are more or less same - with J probably just a bit heavier in terms of pavement loads) is second heaviest, only after 777-300ER.
At some point, there will be limit where you either start to limit airport/max weight ops (as taxiways/runways are not strong enough to sustain), or change the airplane's wingbox (to accomodate wider bogie/more wheels/aditional bogie).

I wonder whether Boeing could've found more space for wider bogie. This seems a perfect solution assuming there are no critical structures in the way. This would also be a good basis for further MTOW raise.

However, I have a feeling it will be one-off without any major redesign. It seems bogies limit Boeing's quest to raise MTOW much more (much longer) than what we see on 'bus front, and I can hardly see them suddenly finding a solution they have not been able to find in past 10 years.

Cheers,
Adam

morrisond wrote:

I think RR designs excellent engines. Unfortunately, until fuel is back over $140/bbl, no one will develop a new widebody or new widebody engine, in my opinion.

Lightsaber"

The big question is how fast will SAF fuels costs drop and what will the required percentages be over time? $140 could be quickly reached when there will be more aggressive policy on SAF percentage increases over time. Even before that, fuel prices would increase as a result of increased demand due to fuel hedging in anticipation of this SAF fuel cost rise. And then you have the time needed till EIS.

AFAIK this is these are the EU blend requirements from mid 2021:

"Starting in 2025, the aviation fuel made available to EU airports should contain 2% SAF, increasing to 5% by 2030, 32% by 2040 and 63% by 2050." https://skynrg.com/news-and-inspiration ... l-mandate/

Note that this is the current requirement, any further ramping up of the schedule would also accelerate the cost increases. If we assume a SAF cost twice that of current jet fuel than a 32% percentage SAF requirement would lead to a 32% increase in fuel cost in 2040. Remember anything you buy in 2030 will still be flying long past 2040 and would have to have acceptable resale value. And as said fuel price would increase earlier based on fuel hedging in anticipation of upcoming percentage increases.

Revelation wrote:

Taxi645 wrote:

Problem is if you only do a 3-4% PIP and you competitor does a 8-10% GTF, you may have saved a lot of investment, but your sales will get a severe hit.

RR is part of the "industry sucking wind" reference. Consider the huge spend on T1000 and their reliance on power by the hour contracts that are big losers when much of world's wide bodies are not flying at all or flying reduced hours, then to do the GTF consider the man hours to move from prototype to production, and all the money for all the tooling that will need to be purchased.

( Note, I typed this before seeing the Lightsaber post that says the same thing far better than I did ).

As said before, the counter argument to that is that the economic value of the fuel savings will also increase with the cost of fuel increasing due to ever increasing SAF percentages.

Personally, while this MTOW bump looks to open up the envelope a bit for Boeing, I doubt it threatens the A350 enough for Airbus to push RR into producing an UltraFan for GTF any time soon.

It does not have to be soon. If Boeing adopts a 2026 EIS PIP and Airbus does 2028-2030 ultrafan EIS, what is Boeing supposed to do then? Almost nullify the investment of said PIP and scramble to launch a GTF after all? They must have a lot of trust in Airbus/RR keeping their powder dry that long. That is a risky stance to take.

Taxi645 wrote:

morrisond wrote:

I think RR designs excellent engines. Unfortunately, until fuel is back over $140/bbl, no one will develop a new widebody or new widebody engine, in my opinion.

Lightsaber"

The big question is how fast will SAF fuels costs drop and what will the required percentages be over time? $140 could be quickly reached when there will be more aggressive policy on SAF percentage increases over time. Even before that, fuel prices would increase as a result of increased demand due to fuel hedging in anticipation of this SAF fuel cost rise. And then you have the time needed till EIS.

AFAIK this is these are the EU blend requirements from mid 2021:

"Starting in 2025, the aviation fuel made available to EU airports should contain 2% SAF, increasing to 5% by 2030, 32% by 2040 and 63% by 2050." https://skynrg.com/news-and-inspiration ... l-mandate/

Note that this is the current requirement, any further ramping up of the schedule would also accelerate the cost increases. If we assume a SAF cost twice that of current jet fuel than a 32% percentage SAF requirement would lead to a 32% increase in fuel cost in 2040. Remember anything you buy in 2030 will still be flying long past 2040 and would have to have acceptable resale value. And as said fuel price would increase earlier based on fuel hedging in anticipation of upcoming percentage increases.

Revelation wrote:

Taxi645 wrote:

Problem is if you only do a 3-4% PIP and you competitor does a 8-10% GTF, you may have saved a lot of investment, but your sales will get a severe hit.

RR is part of the "industry sucking wind" reference. Consider the huge spend on T1000 and their reliance on power by the hour contracts that are big losers when much of world's wide bodies are not flying at all or flying reduced hours, then to do the GTF consider the man hours to move from prototype to production, and all the money for all the tooling that will need to be purchased.

( Note, I typed this before seeing the Lightsaber post that says the same thing far better than I did ).

As said before, the counter argument to that is that the economic value of the fuel savings will also increase with the cost of fuel increasing due to ever increasing SAF percentages.

Personally, while this MTOW bump looks to open up the envelope a bit for Boeing, I doubt it threatens the A350 enough for Airbus to push RR into producing an UltraFan for GTF any time soon.

It does not have to be soon. If Boeing adopts a 2026 EIS PIP and Airbus does 2028-2030 ultrafan EIS, what is Boeing supposed to do then? Almost nullify the investment of said PIP and scramble to launch a GTF after all? They must have a lot of trust in Airbus/RR keeping their powder dry that long. That is a risky stance to take.

That wouldn’t be a wise bet, Ultrafan had an aggressive EIS of 2025 pre-COVID. The latest communication from RR is an EIS of 2028-30 depending on recovery of long haul.
Boeing must have an 787x ready by 2032 latest if they still want to have market share in that segment…

I think the main thing with a MTOW bump and any increase in efficiency 789 becomes the smallest airframe that can do basically any mission and 781 becomes a lot more capable as well covering the vast majority of WB routes.

The common theme we know is that the smallest frame that can do a job is the one that sells in mega volume. Is it right that an 789 has the same number of LD3's as an A359?

It looks like Boeing updated it's pavement loading numbers for the 787 in October - Who speaks pavement loading? What changed?

https://www.boeing.com/resources/boeing ... ps/787.pdf

Taxi645 wrote:

AFAIK this is these are the EU blend requirements from mid 2021:

"Starting in 2025, the aviation fuel made available to EU airports should contain 2% SAF, increasing to 5% by 2030, 32% by 2040 and 63% by 2050." https://skynrg.com/news-and-inspiration ... l-mandate/

Note that this is the current requirement, any further ramping up of the schedule would also accelerate the cost increases. If we assume a SAF cost twice that of current jet fuel than a 32% percentage SAF requirement would lead to a 32% increase in fuel cost in 2040. Remember anything you buy in 2030 will still be flying long past 2040 and would have to have acceptable resale value. And as said fuel price would increase earlier based on fuel hedging in anticipation of upcoming percentage increases.

"Should" is not a requirement, it's a guideline. People don't spend billions of dollars because of "should".

A government requirement to spend more money on an established industry going through its worst crisis ever isn't going to produce more money for them to satisfy that requirement. They'll have to pass the price on to consumers who will just stop buying airline tickets and the crisis will continue. RPMs will drop, PbthH revenue will drop, there will be no funds for new airplanes or new engines.

Taxi645 wrote:

It does not have to be soon. If Boeing adopts a 2026 EIS PIP and Airbus does 2028-2030 ultrafan EIS, what is Boeing supposed to do then? Almost nullify the investment of said PIP and scramble to launch a GTF after all? They must have a lot of trust in Airbus/RR keeping their powder dry that long. That is a risky stance to take.

I predict both will be happy with the status quo. We have no evidence that GE is doing anything major that would provoke RR, and no evidence that RR has the money to productize the UltraFan.

Please keep this thread on topic, thanks.

Revelation wrote:

Taxi645 wrote:

AFAIK this is these are the EU blend requirements from mid 2021:

"Starting in 2025, the aviation fuel made available to EU airports should contain 2% SAF, increasing to 5% by 2030, 32% by 2040 and 63% by 2050." https://skynrg.com/news-and-inspiration ... l-mandate/

Note that this is the current requirement, any further ramping up of the schedule would also accelerate the cost increases. If we assume a SAF cost twice that of current jet fuel than a 32% percentage SAF requirement would lead to a 32% increase in fuel cost in 2040. Remember anything you buy in 2030 will still be flying long past 2040 and would have to have acceptable resale value. And as said fuel price would increase earlier based on fuel hedging in anticipation of upcoming percentage increases.

"Should" is not a requirement, it's a guideline. People don't spend billions of dollars because of "should".

Not sure why you brought this up, perhaps send an email to the writer of the article if you don't like his wording.

https://www.europarl.europa.eu/legislative-train/api/stages/report/current/theme/a-european-green-deal/file/refueleu-aviation

The draft regulation sets minimum obligations for all fuel suppliers to gradually increase the share of advanced biofuels and synthetic
aviation fuels

The only thing uncertain about it that if I'm not mistaken this is still a draft. That said, a lot of environmental legislation has become progressively stricter the past few years so being a draft could also mean the proposed time schedule becomes more aggressive.

Also note that part of the policy is taxation of conventional jet fuel and a reform of the emission rights system.

A government requirement to spend more money on an established industry going through its worst crisis ever isn't going to produce more money for them to satisfy that requirement. They'll have to pass the price on to consumers who will just stop buying airline tickets and the crisis will continue. RPMs will drop, PbthH revenue will drop, there will be no funds for new airplanes or new engines.

True, but as said it also adds economic value to the solution. If this means financing will become sufficiently available I don't know.

I predict both will be happy with the status quo. We have no evidence that GE is doing anything major that would provoke RR, and no evidence that RR has the money to productize the UltraFan.

This could be true. I hope for them that no aviation policy maker is savvy enough to understand that they are leaving by then 15 year old technology on the shelve, in a world that is screaming for a reduced CO2 footprint and airlines (and indeed passengers) having to pay the fuel bills. Because if they do realize that the aviation industry is not pulling it's weight, the SAF time schedule could easily be turned up a few notches.

An increase up to 260t for the 789 as well as for the 781 does not suddenly make it a sunrise capable aircraft. To make it to 9500nm the 789 would take ~155pax. The A359 was deemed unsuitable and could do it with ~180pax (and lower fuel burn per pax) The selected aircraft (A35K) is capable to do it with ~275pax and the lowest fuel burn per pax of the three.

Fred


Sent from my iPad using Tapatalk

Opus99 wrote:

gloom wrote:

lightsaber wrote:

I thought the gear was the weight limit? Specifically the pavement loading.

Exactly this.

Wiki has a list, which looks more-or-less reliable.
https://www.youtube.com/watch?v=VEuYn9_e1Ac
In terms of PCR, 787-9 (and J, as weights/dimensions are more or less same - with J probably just a bit heavier in terms of pavement loads) is second heaviest, only after 777-300ER.
At some point, there will be limit where you either start to limit airport/max weight ops (as taxiways/runways are not strong enough to sustain), or change the airplane's wingbox (to accomodate wider bogie/more wheels/aditional bogie).

I wonder whether Boeing could've found more space for wider bogie. This seems a perfect solution assuming there are no critical structures in the way. This would also be a good basis for further MTOW raise.

However, I have a feeling it will be one-off without any major redesign. It seems bogies limit Boeing's quest to raise MTOW much more (much longer) than what we see on 'bus front, and I can hardly see them suddenly finding a solution they have not been able to find in past 10 years.

Cheers,
Adam

With the update apparently, the landing gear can be strengthened no issue. Pavement loading will still be lower than a 300ER

I'm Guessing as they said no structural changes that they found the gear could carry the extra weight. I'm betting that it could easily carry the added weight for T-O and as they are keeping the Landing weights the same there was no need to increase strength & weight. result same gear as all the other -9/-10 series. No extra parts to carry.

rbavfan wrote:

Opus99 wrote:

With the update apparently, the landing gear can be strengthened no issue. Pavement loading will still be lower than a 300ER

I'm Guessing as they said no structural changes that they found the gear could carry the extra weight. I'm betting that it could easily carry the added weight for T-O and as they are keeping the Landing weights the same there was no need to increase strength & weight. result same gear as all the other -9/-10 series. No extra parts to carry.

If so, it will become limited on some (smaller) airports the 787 revolution was aiming at. There's always a tradeoff. We'll see,
I still find it difficult to believe it turned out to be possible when it was at hand for past few years.

Cheers,
Adam

Apologies for the size of the image but hopefully its useful to get the image across.

As before each of the 8 charts shows relative performance of the jets B789 on the top followed by 781 next then A59 and the A35K on the bottom.
The left row shows the 787s with increased 260t takeoff weights and the right with standard 254t weights. The green areas represent where the particular aircraft has the lowest CASM, the blue where it is within 5% of the lowest CASM and the red where it is over 5% off the lowest CASM. The X axis on each chart is the Range (1-9000nm) and the Y axis shwing the potential payload available to be taken on the mission (demonstating the ability of an aircraft to offset the Pax costs through freight).


As expected the band of green increased for the 781 and the green shifted upwards in range for the 789. Correspondingly the band of green for the A359 reduced in size as the sweet spot for the 789 claimed some of those mission profiles. Th A35k remains the aircraft of choice for long range and high payload mission but below 6000nm has to be taking an awful lot of payload to be useful but isnt influenced by the changes to the 787 (hence its unlikely that the Sunrise routes will suddenly go to the 787 with a 260t MTOW implemented).

The big change that I noticed in the charts was more along the available mission profiles that are within 5% of the minimum CASM. The big opportunity opened up by the weight increases for the 789 is in the higher payload at higher ranges and the huge flexibility of the blue area with the A359 would be basically matched by the 789. The low end of the competitive space for the 787 and A359 appear to be Sub 4knm with less than 10t of cargo, this is the narrowbody territory.

Off topic: As I write this I realise why the 781 hasnt sold as well as one might expect the "CASM King" to do and its that whilst is is clearly better than the volume selling 789 and A359 the latter are "good enough" for much more of the spectrum.

Fred

Opus99 wrote:

flipdewaf wrote:

Apologies for the size of the image but hopefully its useful to get the image across.

As before each of the 8 charts shows relative performance of the jets B789 on the top followed by 781 next then A59 and the A35K on the bottom.
The left row shows the 787s with increased 260t takeoff weights and the right with standard 254t weights. The green areas represent where the particular aircraft has the lowest CASM, the blue where it is within 5% of the lowest CASM and the red where it is over 5% off the lowest CASM. The X axis on each chart is the Range (1-9000nm) and the Y axis shwing the potential payload available to be taken on the mission (demonstating the ability of an aircraft to offset the Pax costs through freight).


As expected the band of green increased for the 781 and the green shifted upwards in range for the 789. Correspondingly the band of green for the A359 reduced in size as the sweet spot for the 789 claimed some of those mission profiles. Th A35k remains the aircraft of choice for long range and high payload mission but below 6000nm has to be taking an awful lot of payload to be useful but isnt influenced by the changes to the 787 (hence its unlikely that the Sunrise routes will suddenly go to the 787 with a 260t MTOW implemented).

The big change that I noticed in the charts was more along the available mission profiles that are within 5% of the minimum CASM. The big opportunity opened up by the weight increases for the 789 is in the higher payload at higher ranges and the huge flexibility of the blue area with the A359 would be basically matched by the 789. The low end of the competitive space for the 787 and A359 appear to be Sub 4knm with less than 10t of cargo, this is the narrowbody territory.

Off topic: As I write this I realise why the 781 hasnt sold as well as one might expect the "CASM King" to do and its that whilst is is clearly better than the volume selling 789 and A359 the latter are "good enough" for much more of the spectrum.

Fred

So Fred what it sounds like you’re saying is. The real threat here to the a359 is the 789

Basically yes, the 789 and the A359 appear to compete much closer than the 781 and the A359 do. If I were airbus the simple stretch to the A359 might look very interesting.

Fred