There have now been a few years experience of these alternatives for making fuselages, is there any indication of which method is likely to be the favoured one for new aircraft familiesg- e.g the 767/A300-sized replacements - going forward? Or will it represent too much loss of face for either manufacturer to switch?

There's lot's of interesting articles out there. This is one:
https://www.compositesworld.com/opportu ... -aircraft/
The gist: Move away from autoclave cured prepregs to resin infusion and thermoplastics. Neither dictates barrel v panel. They do mention reduced assembly with single piece integrated structures. The 787 barrels are by definition "more integrated". However, if you want, say, frames co-cured with floor beams it might favour panel construction. So we saw with the A350-1000 the introduction of some monolithic frames (basically the tape is laid around a mandrel that resulted in a sort of square cross-section hula-hoop, then cut in 2 to give 2 C shaped frames).

I haven't seen the debate move on meaningfully (in the wider public domain) in the last 10 years to be honest. Are the extra lateral lap joints in an A350 offset by designing the tape layup around tension, compression and shear in the 4 quadrants? I haven't read anything either way, and as for empirical evidence, I suspect it's in the noise. As for loss of face, the next application of composite fuselages will likely be on the narrow body replacements, for which the emphasis will be on production scalability, and may favour different solutions anyway.

Considering the issues Boeing is having with assembling the big barrels, you have to wonder what would have happened had they gone for panels.

Aesma wrote:

Considering the issues Boeing is having with assembling the big barrels, you have to wonder what would have happened had they gone for panels.

The Boeing 787 quality control issues evolved over time, and are not inherent to the method itself. It requires exacting tolerances and assembly. Boeing is perfectly capable of that precision, it just wasn't maintained as it should have been.

I don't think there is a clear verdict of one method over the other. Both have advantages and disadvantages.

Is one method cheaper? What about weight? I assume that barrels are cheaper for assembly.

I’d be very surprised if future clean sheet jet transports have composite fuselages

The enormous complexity and cost of construction doesn’t seem to pay off. There doesn’t seem to be much weight savings over conventional aluminum which is still improving, most of the fuel efficiency in the 787 and A350 comes from the advanced engines and aerodynamics

Max Q wrote:

I’d be very surprised if future clean sheet jet transports have composite fuselages

The enormous complexity and cost of construction doesn’t seem to pay off. There doesn’t seem to be much weight savings over conventional aluminum which is still improving, most of the fuel efficiency in the 787 and A350 comes from the advanced engines and aerodynamics

The benefit of composites is in strength-to-weight ratio. Which allows greater flexibility in design, in return for greater complexity in construction. It's a trade like anything else.

Composites are not going away, as there will be improvements in manufacturing and assembky technologies. Aluminium is not going away either, there will always be some applications where it is preferred over composites. They are both tools in the toolbox for aircraft designers.

Avatar2go wrote:

Max Q wrote:

I’d be very surprised if future clean sheet jet transports have composite fuselages

The enormous complexity and cost of construction doesn’t seem to pay off. There doesn’t seem to be much weight savings over conventional aluminum which is still improving, most of the fuel efficiency in the 787 and A350 comes from the advanced engines and aerodynamics

The benefit of composites is in strength-to-weight ratio. Which allows greater flexibility in design, in return for greater complexity in construction. It's a trade like anything else.

Composites are not going away, as there will be improvements in manufacturing and assembky technologies. Aluminium is not going away either, there will always be some applications where it is preferred over composites. They are both tools in the toolbox for aircraft designers.

I'm possibly mistaken, so someone please correct me regarding the strength of composite vs. aluminum tubes. My understanding is that composite fuselages are largely able to maintain a 6,000' cabin altitude over their lifetime cycles vs. the typical 8,000' altitude of aluminum fuselages. If this is indeed the case: That's a very powerful metric for the strength composites over metal alloys.

But that's only one datum, which I don't know to be correlative. So if it's NOT the fuselage construction material, what would account for the lower cabin altitudes (in airliners only.. bizjets are a whole different animal) in which the newer aircraft are flying their passengers?

rjsampson wrote:

I'm possibly mistaken, so someone please correct me regarding the strength of composite vs. aluminum tubes. My understanding is that composite fuselages are largely able to maintain a 6,000' cabin altitude over their lifetime cycles vs. the typical 8,000' altitude of aluminum fuselages. If this is indeed the case: That's a very powerful metric for the strength composites over metal alloys.

But that's only one datum, which I don't know to be correlative. So if it's NOT the fuselage construction material, what would account for the lower cabin altitudes (in airliners only.. bizjets are a whole different animal) in which the newer aircraft are flying their passengers?

Cabin altitude is a function of the hoop stress strength of the fuselage, and the number of pressure cycles it will endure before weakening by fatigue.

The fuselage can be designed for the desired altitude
& life with either material, it's just a matter of the weight that will result, and how that fits into the economic model of the aircraft. Composites enabled the jump to lower altitudes with less weight restriction. But not impossible to design in aluminum. Again it's a trade.

Chemist wrote:

Is one method cheaper? What about weight? I assume that barrels are cheaper for assembly.

I'm a total layman in this area but Boeing's method is possibly cheaper considering that the nominal price of a 787 is surprisingly low and equal to the official price of an A330neo (while being a more modern and more competitive aircraft).

rigo wrote:

Chemist wrote:

Is one method cheaper? What about weight? I assume that barrels are cheaper for assembly.

I'm a total layman in this area but Boeing's method is possibly cheaper considering that the nominal price of a 787 is surprisingly low and equal to the official price of an A330neo (while being a more modern and more competitive aircraft).

Where are you getting your figures from? For all companies that sort of information is highly confidential.

I know it is commonly discussed here but I have seen no real proof- just A-Net lore.

StTim wrote:

rigo wrote:

Chemist wrote:

Is one method cheaper? What about weight? I assume that barrels are cheaper for assembly.

I'm a total layman in this area but Boeing's method is possibly cheaper considering that the nominal price of a 787 is surprisingly low and equal to the official price of an A330neo (while being a more modern and more competitive aircraft).

Where are you getting your figures from? For all companies that sort of information is highly confidential.

I know it is commonly discussed here but I have seen no real proof- just A-Net lore.

I'm referring to the publicly known prices, not the actual deals between Airbus or Boeing and the airlines. A simple google search for "787-9 price" returns USD 292.5M, while for the A330-900 it gives USD $296.4M. So according to the official figures at least, 787-9 is in fact cheaper.

rigo wrote:

StTim wrote:

rigo wrote:

I'm a total layman in this area but Boeing's method is possibly cheaper considering that the nominal price of a 787 is surprisingly low and equal to the official price of an A330neo (while being a more modern and more competitive aircraft).

Where are you getting your figures from? For all companies that sort of information is highly confidential.

I know it is commonly discussed here but I have seen no real proof- just A-Net lore.

I'm referring to the publicly known prices, not the actual deals between Airbus or Boeing and the airlines. A simple google search for "787-9 price" returns USD 292.5M, while for the A330-900 it gives USD $296.4M. So according to the official figures at least, 787-9 is in fact cheaper.

The official figures are just numbers without much real-world significance.

Starlionblue wrote:

rigo wrote:

StTim wrote:

Where are you getting your figures from? For all companies that sort of information is highly confidential.

I know it is commonly discussed here but I have seen no real proof- just A-Net lore.

I'm referring to the publicly known prices, not the actual deals between Airbus or Boeing and the airlines. A simple google search for "787-9 price" returns USD 292.5M, while for the A330-900 it gives USD $296.4M. So according to the official figures at least, 787-9 is in fact cheaper.

The official figures are just numbers without much real-world significance.

They also include different items such that my understanding was the Airbus figure (perhaps flight of fancy would be more appropriate) includes more than the Boeing one.

Avatar2go wrote:

Aesma wrote:

Considering the issues Boeing is having with assembling the big barrels, you have to wonder what would have happened had they gone for panels.

The Boeing 787 quality control issues evolved over time, and are not inherent to the method itself. It requires exacting tolerances and assembly. Boeing is perfectly capable of that precision, it just wasn't maintained as it should have been.

I don't think there is a clear verdict of one method over the other. Both have advantages and disadvantages.

The weight argument always revolves around the fact that Airbus can use larger panels whereas Boeing doesn't need fasteners at the quadrants. But doesn't that tradeoff work out differently depending on the diameter and length of the fuselage? Is it possible that the barrels assembly method is optimal for the 787 and panels are optimal for the A350?

rigo wrote:

The weight argument always revolves around the fact that Airbus can use larger panels whereas Boeing doesn't need fasteners at the quadrants. But doesn't that tradeoff work out differently depending on the diameter and length of the fuselage? Is it possible that the barrels assembly method is optimal for the 787 and panels are optimal for the A350?

Actually the fasteners are just one part of the weight equation. There is also the thickness & composition requirements of the materials. Boeing uniform barrel sections are inherently stronger per unit weight. But Airbus using the panel sections, can optimize them to be thicker or thinner for the loads at their location. So it's complicated and there is not a clear advantage of one over the other.

The aspect that dominates the assembly decision more than weight, is the investment in tooling vs labor. Boeing shot for the moon in developing tooling and techniques at an entirely new scale, but that would reduce labor and enable high production rates. Airbus took a less risky approach, with large panels that are easier to fabricate, but more labor intensive. Then went after the labor costs with increased automation.

Once those decisions are made, they were both fully committed, there is no going back on those investments. The overall goal was to develop the technology at the lower production rates of the widebody, but hopefully then apply it to the higher production rates of a narrow body.

That is proving difficult for both approaches. Both Boeing and Airbus are working on this transition, but the economics are not as good for smaller aircraft that need to be produced at higher rates. So it's a work in progress. But is the ultimate payoff for the methods they each have chosen.

One indicator will be if either adopts the processes of the other in the next generation of narrow bodies, or if they will stick with what they have now. This will need to evolve in the direction of lowest cost/greatest benefit. So if those are about the same, there won't be much change in approach.

Avatar2go wrote:

rigo wrote:

The weight argument always revolves around the fact that Airbus can use larger panels whereas Boeing doesn't need fasteners at the quadrants. But doesn't that tradeoff work out differently depending on the diameter and length of the fuselage? Is it possible that the barrels assembly method is optimal for the 787 and panels are optimal for the A350?

Actually the fasteners are just one part of the weight equation. There is also the thickness & composition requirements of the materials. Boeing uniform barrel sections are inherently stronger per unit weight. But Airbus using the panel sections, can optimize them to be thicker or thinner for the loads at their location. So it's complicated and there is not a clear advantage of one over the other.

The aspect that dominates the assembly decision more than weight, is the investment in tooling vs labor. Boeing shot for the moon in developing tooling and techniques at an entirely new scale, but that would reduce labor and enable high production rates. Airbus took a less risky approach, with large panels that are easier to fabricate, but more labor intensive. Then went after the labor costs with increased automation.

Once those decisions are made, they were both fully committed, there is no going back on those investments. The overall goal was to develop the technology at the lower production rates of the widebody, but hopefully then apply it to the higher production rates of a narrow body.

That is proving difficult for both approaches. Both Boeing and Airbus are working on this transition, but the economics are not as good for smaller aircraft that need to be produced at higher rates. So it's a work in progress. But is the ultimate payoff for the methods they each have chosen.

One indicator will be if either adopts the processes of the other in the next generation of narrow bodies, or if they will stick with what they have now. This will need to evolve in the direction of lowest cost/greatest benefit. So if those are about the same, there won't be much change in approach.

I remember reading somewhere that the consensus was that composite fuselages currently make no sense for narrowbodies, as at those sizes, the weight savings would be too small to justify the extra cost. The fact that none of the recent narrowbody designs (A220, C919, MC-21) uses a composite fuselage.seems to confirm that.

rigo wrote:

I remember reading somewhere that the consensus was that composite fuselages currently make no sense for narrowbodies, as at those sizes, the weight savings would be too small to justify the extra cost. The fact that none of the recent narrowbody designs (A220, C919, MC-21) uses a composite fuselage.seems to confirm that.

Yes, not only cost, but also production rate must be much quicker. The supply chain could not generate large composite sections at that rate, the fabrication time is too long. Aluminum is much faster.

Starlionblue wrote:

rigo wrote:

StTim wrote:

Where are you getting your figures from? For all companies that sort of information is highly confidential.

I know it is commonly discussed here but I have seen no real proof- just A-Net lore.

I'm referring to the publicly known prices, not the actual deals between Airbus or Boeing and the airlines. A simple google search for "787-9 price" returns USD 292.5M, while for the A330-900 it gives USD $296.4M. So according to the official figures at least, 787-9 is in fact cheaper.

The official figures are just numbers without much real-world significance.

True...simply the ballpark comparison does carry some water...reasonably, and broadly speaking, the two aircraft seem to be similar in price...


Faro

Faro wrote:

Starlionblue wrote:

rigo wrote:

I'm referring to the publicly known prices, not the actual deals between Airbus or Boeing and the airlines. A simple google search for "787-9 price" returns USD 292.5M, while for the A330-900 it gives USD $296.4M. So according to the official figures at least, 787-9 is in fact cheaper.

The official figures are just numbers without much real-world significance.

True...simply the ballpark comparison does carry some water...reasonably, and broadly speaking, the two aircraft seem to be similar in price...


Faro

I think the effective deals offered to airlines would obviously be different, but not *that* different - I suppose some may buy 787s for say 240M but certainly not 60M. And the discounts given by Airbus and Boeing would presumably be roughly the same anyway.

rigo wrote:

Faro wrote:

Starlionblue wrote:

The official figures are just numbers without much real-world significance.

True...simply the ballpark comparison does carry some water...reasonably, and broadly speaking, the two aircraft seem to be similar in price...


Faro

I think the effective deals offered to airlines would obviously be different, but not *that* different - I suppose some may buy 787s for say 240M but certainly not 60M. And the discounts given by Airbus and Boeing would presumably be roughly the same anyway.

If you are a 777X customer, 60M might just be the 787's price with all those delay compensations

What I'm trying to say. These are very complicated products with many dimensions. You can't just put a price sticker on them as on a gallon of milk.