Most everyone here is aware of the fact that the 787-8 is substantially different from the -9 and -10 (both of which are fairly similar.) While it seems that for shorter-range missions, the 787-8's target market may be assumed by a future NMA variant, what would the technical (i.e. ignoring market realities for the sake of discussion) possibility be of creating a 787-8-sized shrink of the 787-9, geared toward longer range flights? Obviously this would increase commonality (which is currently low) with the larger variants. Does anyone want to throw out what sort of range might be possible with such an aircraft? And think of the possibilities as a state aircraft or BBJ...

Boeing tried that concept already with the 777-200LR and it got a few bites but nothing incredibly substantial. With the extremely high development costs for the 787 I just can't see Boeing trying to certify a completely new variant.

Well, the 787-3 was proposed in the early stages of developing the 787 series (although I think that was actually supposed to target shorter routes with higher density/capacity, which is the polar opposite of what an "LR" 787 version would look like...)

FA9295 wrote:

Well, the 787-3 was proposed in the early stages of developing the 787 series (although I think that was actually supposed to target shorter routes with higher density/capacity, which is the polar opposite of what an "LR" 787 version would look like...)

It was. -3 was the type JL and NH ordered most, for domestic operations.

Who's going to buy it?

Boeing's proposed the idea, particularly to QF IINM, and found no real interest.

Not surprising, as the CASM would likely be quite a bit higher than the -9 without much additional benefit, in range or otherwise.

Boeing has recently already changed a good bit of the 787-8 design in order to make it more similar to the 787-9. But that's mostly for production efficiency reasons, not to improve the performance of the 787-8. So it's not that obvious that these kind of changes improve the performance that much that it will easily be turned into a ULR plane. It might be easier to make changes to the current 787-9 to create such a plane. With the 777-8 also coming up it won't be a priority for Boeing to be creating another ULR plane right now.

Considering the current range of the 787-9 it could be turned into an ULR plane just by fitting next generation engines which will certainly happen at some point in the future.

N328KF wrote:

Most everyone here is aware of the fact that the 787-8 is substantially different from the -9 and -10 (both of which are fairly similar.) While it seems that for shorter-range missions, the 787-8's target market may be assumed by a future NMA variant, what would the technical (i.e. ignoring market realities for the sake of discussion) possibility be of creating a 787-8-sized shrink of the 787-9, geared toward longer range flights? Obviously this would increase commonality (which is currently low) with the larger variants. Does anyone want to throw out what sort of range might be possible with such an aircraft? And think of the possibilities as a state aircraft or BBJ...

Unfortunately I didn't keep the reference, however some months ago there were some news pieces on the Charleston 787 line; wherein the Production Manager outlined some reasonably substantial changes to the 788. The effect was to bring that model into far closer alignment with the 789 and 78X than previously had been the case.

It had been a given wisdom that BA had basically abandoned the 788 for further development; however now BA has clearly invested significant funds to standardise production & drive costs down.

So prima facie the 788 is now being actively offered to customers once again; and indeed AA will now be taking a further 22 frames.

My point being - maybe it would now be better to modify the actual 788 for such a task?

cheers

Here are articles and a previous thread about the 788's modification for more commonality with 789/78X

https://leehamnews.com/2018/04/17/boein ... mmonality/

viewtopic.php?t=1392143

My estimate says with:
Increased MTOW to 254011kg (same as the 789)
Same MZFW 161025kg
the increase in OWE is about 3t heavier giving 123t
The number of pax is 218

Max payload range goes up to 7825nm (remember max payload is actually 3t less)
Max fuel volume limited range is 8760nm
Max range with 218 (and no fuel volume limitation) would be ~9700nm.

Fred

LAX772LR wrote:

Who's going to buy it?

Boeing's proposed the idea, particularly to QF IINM, and found no real interest.

Not surprising, as the CASM would likely be quite a bit higher than the -9 without much additional benefit, in range or otherwise

As was stated in my original post, I wasn't really interested in marketability. It's purely a technical thought exercise. And as someone else mentioned within the thread, it sounds as if the hypothetical gain might be about 1000nm – not insignificant.

brindabella wrote:

Unfortunately I didn't keep the reference, however some months ago there were some news pieces on the Charleston 787 line; wherein the Production Manager outlined some reasonably substantial changes to the 788. The effect was to bring that model into far closer alignment with the 789 and 78X than previously had been the case.

LAX772LR wrote:

Here are articles and a previous thread about the 788's modification for more commonality with 789/78X

https://leehamnews.com/2018/04/17/boein ... mmonality/

viewtopic.php?t=1392143

The forthcoming commonality changes in the 787-8 aft section aren't what I was suggesting; I was suggesting a simple shrink of the -9 to have the same length as the -current -8. It is in effect the same treatment given to the 777-300ER to give us the current -200LR.

flipdewaf wrote:

My estimate says with:
Increased MTOW to 254011kg (same as the 789)
Same MZFW 161025kg
the increase in OWE is about 3t heavier giving 123t
The number of pax is 218

Max payload range goes up to 7825nm (remember max payload is actually 3t less)
Max fuel volume limited range is 8760nm
Max range with 218 (and no fuel volume limitation) would be ~9700nm.

Fred

I think it is about right.
Recently my blog posted an entry titled "Payload Range for 787-10", in which there is a link to a spreadsheet with 787 payload range.

Basically it says that you can easily achieve 9,500 nmi of range with 150 passengers if the 787-8 gets 560,000 lb MTOW and auxiliary fuel tanks to increase the total useable fuel by 12%.

I cannot put the link to the article because moderators will remove this comment for "self promotion".

LAX772LR wrote:

Here are articles and a previous thread about the 788's modification for more commonality with 789/78X

https://leehamnews.com/2018/04/17/boein ... mmonality/

viewtopic.php?t=1392143

Thank you - that's incredible to read that there is only 30% commonality between 787-8 and the larger ones. Is there anywhere that outlines the differences between them?

N328KF wrote:

LAX772LR wrote:

Who's going to buy it?

Boeing's proposed the idea, particularly to QF IINM, and found no real interest.

Not surprising, as the CASM would likely be quite a bit higher than the -9 without much additional benefit, in range or otherwise

As was stated in my original post, I wasn't really interested in marketability. It's purely a technical thought exercise. And as someone else mentioned within the thread, it sounds as if the hypothetical gain might be about 1000nm – not insignificant.

brindabella wrote:

Unfortunately I didn't keep the reference, however some months ago there were some news pieces on the Charleston 787 line; wherein the Production Manager outlined some reasonably substantial changes to the 788. The effect was to bring that model into far closer alignment with the 789 and 78X than previously had been the case.

LAX772LR wrote:

Here are articles and a previous thread about the 788's modification for more commonality with 789/78X

https://leehamnews.com/2018/04/17/boein ... mmonality/

https://www.airliners.net/forum/viewtopic.php?t=1392143

The forthcoming commonality changes in the 787-8 aft section aren't what I was suggesting; I was suggesting a simple shrink of the -9 to have the same length as the -current -8. It is in effect the same treatment given to the 777-300ER to give us the current -200LR.

Quite so.

My point being that if one actually wanted to do it, then starting from the 788 might save a heap of time, money etc etc.

cheers

LAX772LR wrote:

Who's going to buy it?

Boeing's proposed the idea, particularly to QF IINM, and found no real interest.

Not surprising, as the CASM would likely be quite a bit higher than the -9 without much additional benefit, in range or otherwise.

I think you hit the nail on the head. Trip costs of the 787-9 and 787-8 are very similar, no?

So, what advantage would a 787-8LR have? The 787-9 can have a premium heavy config and fly very, very far or you can pack it to the gills and still fly pretty far.

Unlike the 777-200LR which seemed to give a significant boost to range and hot/high performance, this seems like a waste of money (and the 777-200LR was a waste of money, it seems).

So how about another use case? A "787-8F" based upon a shrunken 787-9?

FA9295 wrote:

Well, the 787-3 was proposed in the early stages of developing the 787 series (although I think that was actually supposed to target shorter routes with higher density/capacity, which is the polar opposite of what an "LR" 787 version would look like...)

The 783 was indeed much more of a 788SR. It was dropped to prioritise delivery of the 788 and also because it was established that the operating economics would be trash - to the extent that the 788 was more efficient once stage length got past something like 400 nmi.

N328KF wrote:

LAX772LR wrote:

Boeing's proposed the idea, particularly to QF IINM, and found no real interest.
Not surprising, as the CASM would likely be quite a bit higher than the -9 without much additional benefit, in range or otherwise

As was stated in my original post, I wasn't really interested in marketability. It's purely a technical thought exercise. And as someone else mentioned within the thread, it sounds as if the hypothetical gain might be about 1000nm – not insignificant.

The two can't be separated:
Boeing *could* make the thing fly 12,000nm+ if they wanted to. That's physically possible.
Selling it wouldn't be though, due to the ridiculous amount of compromises that doing so would require.

If you're here to only speculate about physical possibilities unbound by the realities of market viability, then perhaps CivAv isn't the forum to do it... that's more fit for fantasy aircraft.

WorldFlier wrote:

this seems like a waste of money (and the 777-200LR was a waste of money, it seems).

As a standalone, perhaps... but it doesn't stand alone.

The overwhelming majority of its engineering was already done on the 77W (and 777 platform in general before it), then later also useful/continued for the 77F.

And that's just the direct costs; it doesn't factor in the relevant intangibles such as customer retention. Even if Boeing sold those 60ish aircraft for a ridiculous discount akin to $100M-- that's still over $6Billion in revenue that it prevented from going to its competitor, and that's just acquisition. I'd be shocked if that alone didn't cover Boeing's expenses.

tigamilla wrote:

Is there anywhere that outlines the differences between them?

A 787-8LR will be the natural evolution of the 787 and it is not really about range.

(1) The original 787-8 is only about 35~40% common with the 787-9 and 787-10. The -9 and -10 however are about 90% common. For one thing, it lacked the active boundary layer control on the tail surfaces and there were changes to the wing box and how various stuff are fastened. This is not in Boeing or any of their customers interests -- not in manufacturing economics and not in support logistics. Already Boeing is addressing this. In April 2018 they moved to a common tail unit to increease commonality for production savings.

(2) The 787-8 is very much a Maximum Take Off Weight limited aircraft. There is a negligible difference in the maximum fuel capacity of the -8 and the -9 (101.3 tonnes vs 101.5 tonnes). The reason the 787-8 has about 300nm less range despite being a smaller, lighter, aircraft is that it is limited to a MTOW of 227.9 tonnes (vs 254.0 tonnes for the -9). In a typical cabin layout and payload allowance, the 787-8 cannot fill her tanks to capacity without exceeding its MTOW.

(3) A 787-8LR will essentially be a 787-9 shortened by 6.1m. It will have 90% or higher commonality for production and logistical economics. This will be the primary motivation for the model. As a side benefit, range will improve to about 8,600 nm as it will have the same MTOW as the 787-9 and the ability to carry the full fuel load while weighing about 8.9 tons less empty. This is equivalent to about 1hr 45 mins of extra cruise time (vs the 787-9) at 560nm per hour and adds about 1000nm to the effective range.

Arguably Boeing made the 77L really to be the basis for the 77F, so they could do the same again but isnt the 789 already earmarked to be the eventual 78F?

TWA772LR wrote:

Arguably Boeing made the 77L really to be the basis for the 77F, so they could do the same again but isnt the 789 already earmarked to be the eventual 78F?

Well, we'll see about that. Again, this is another reason they may pull the trigger on the 787-8LR and sooner rather than later. To put it simply, the 787-9 as a freighter will have a lot of cargo room without the MTOW to actually use it. We are not talking about IL-76, Superguppy, Beluga or Dreamlifter duties here. That's a completely different market for massively oversized but relatively light "things". If your nose and/or tail doesn't open up you are not even remotely in that market -- which is in part why the 747-8F remains popular. We are talking UPS/FedEx/EVA air cargo duties. In general, a modern wide body cargoliner will reach MTOW way before it fills up the cargo hold. A passenger and his luggage is pretty light compared to packages and other stuff sent on air freight. Think about it... all that space in front of you, above you, beneath your butt, the aisles, etc are all air space. The same is not true of an LD4 or LD3 container or a pallet shrink wrapped with cargo.

Let's look at the numbers. The benchmark of the business -- the 777F (aka 777-200LRF) -- has 151 cu-m of room on the cargo deck and 502 cu-m on the main deck. It has 204 tonnes to share between whatever goes into this 653 cu-m of cargo space and fuel. At the maximum fuel load of 145 tonnes, the 777F can only carry about 59 tonnes of "stuff". That is around 11 cu-m per tonne.

The 787-9 has 173 cu-m of space on the lower deck and about 450 cu-ft on the main deck. That is 623 cu-m of cargo space. But, the 787-9 only has 125 tonnes to share between that and it's ability to carry 101 tonnes of fuel. At maximum fuel the 787-9 can only carry 24 tonnes of stuff in that 623 cu-m of space. That is a very sparse 26 cu-m per tonne. As you can see, this is one cargoliner which can carry a lot less payload than it has space for (relative to the 777F).

A 787-8LRF will be a better product by offering the same MTOW, but 9 additional tonnes of payload at maximum fuel load. Naturally, none of these cargoliners typically operate with maximum fuel; they usually tend to carry as much payload as they can and only enough fuel for the route they fly. However, it is easy to see that there is very little justification for a 787-9F with 95% the volume of the 777F but only 61% the combined cargo+fuel load capacity. The 787-8LRF has a much healthier ratio of 75% the 777F's cargo volume with 65% the combined cargo+fuel load capacity.

The only justification for the 787-9F is the lack of a 787-8LRF.

It's most likely that Boeing will launch the 797/mom.However if they didn't perhaps its more likely that they would go in the reverse direction for the ( now nearly common build) 787 but Keeping all the lighter 'bits' like the -8 MLG.Design a new wing optimised for 5knm and fit the 50klbs engines that are mooted for the mom as an alternative cheaper to create mom on existing production lines.Wouldnt be as good as a clean sheet mom but far better than anything else out there.
Using existing production lines and most of 787 frame would keep the costs way down.Accepted it's v unlikely but perhaps more of a market than a tiny ULR aircaft.

IMO the most obvious next development of the 787 line is not an 8LR but a 10ER. However this is not going to happen for a long time because it would be such a good aircraft, that it would put an early nail in the coffin of the 777X. The only way imo we will see significant further development of the 787 (apart from freighter) is if Airbus start to get on top of Boeing with the 359, and I just can't see that happening.

Ruscoe