...and the market seems to be saying that it likes frequency and versatility.
And here's the best option for frequency and versatility:
Instead of flying 3x daily 787/A350's, just fly 100x daily Global 6500 business jets with 10-15 pax.
And you could offer direct routes like BNA-PSA or JAX-MUC, which should have a few PDEW.
Obviously the market cares about frequency and versatility, yes, but also efficiency.
When smaller, more versatile planes take little to no efficiency hit - as with A380 vs. 787/A350 - then airlines use the smaller planes.
When the efficiency implications of scale are very significant, however, there would be a different calculus.
The underlying economics of airliner trends (i.e. efficiency vs. capacity tradeoff) explain the market at a deeper level than a simple description of size category trends. Change the economics sufficiently and you can change the trends.
I estimate a little more weight and a climb fuel burn penalty, so less of fuel burn savings. I also dream of that efficient of wing tip treatment.
Re climb fuel burn penalty: I estimate a lower T/W ratio for a NEO and therefore a longer climb.
But the aerodynamics of climb - the excess lift and lower speeds - mean that 70-80% of A380 drag during climb is induced rather than parasitic.
The L/D delta, therefore, would be closer to the (inverse of) Di delta: on the order of 25% better climb L/D.
I haven't dug deeply into the math but it seems conservative to estimate that a winglet-ed NEO would have a more fuel-efficient climb, even if that climb were longer in duration. But I'd love to hear your reasons for thinking otherwise.
Re weight I estimate a big savings on engine weight. More on that below.
So far, we don't know what they would do to the wing. Do they have the room to widen the span for the 15% advantage? Airbus says the sharklets increased fuel efficiency on the 320 by 4%, so working backwards, what is the L/D efficiency improvement due to the sharklets? What gains did the 330neo see?
Good questions re A320 and A330 winglets.
Here again we have to look at the underlying reasons for the deltas rather than solely at the observed outcomes.
A320 and A330's drag breakdowns are ~35% induced drag. For the A380 Di is ~55%.
Winglets work by reducing Di at a cost of some Dp and weight delta.
So at first cut you have >40% more impact from similar winglets on A380 versus A320/330.
Then at second cut you consider the Di vs. Dp/weight tradeoff made in optimizing winglet size. A320/330 could have seen further Di delta from bigger winglets, but at some point the Dp/weight delta outweighs the Di delta. For the A380 that crossover point is further out because Di is a bigger portion of drag, implying that the optimal winglet for an A380 is significantly larger than for the A320/330.
New gen engines have been at least as heavy as the previous gen engines, (usually heavier).
That's probably right to a certain extent but not a law of nature. And it isn't so right that the principle overcomes the math of particular cases.
GTF allows for a shorter core with fewer stages as the compressors spin faster. Ultrafan will a shorter, slim-line nacelle that reduces weight somewhat - though core weight is most of engine dry weight.
The A380's engines have low T/W ratios of ~5. I expect Ultrafan T/W to be around ~5.5.
As with most things A380, any discussion of future versions has to be grounded in how bad the current version is. The A388's engines are far too big and heavy for it.
Would they even bother changing the empennage?
The A380's empennage is 90% the area (and therefore the drag) of one wing. They'd be insane not to change it.
Empennages don't get much mention on A.net because... well people just don't know enough. But this is a huge opportunity for A380 efficiency delta.
Airbus planned to change the empennage as part of its last round of A380NEO discussions. http://aviationweek.com/airbus-a380/lea ... on-nearing
The last thing I read was that a stretch would increase seats by 50, which is closer to a 10% increase than 20%.
Why believe what you read when basic arithmetic can tell us more?
A 31ft stretch to the A380 would add 1178ft2 of cabin area (248in and 208in-wide decks). That's 20% of the A380's current cabin area.
20% capacity delta from a 20% cabin area delta underestimates the capacity impact: we'd be adding only the most efficient constant section, and wouldn't need to add any doors.
Plus I haven't accounted for any of the "A380plus" revisions - smaller stairs etc. - that should give another ~3% capacity delta (I don't buy Airbus' higher marketing figures and neither do the airlines obviously).
Plus there are other NEO options - sidewall shaving, aft bulkhead revision.