- FTA: The extensions, each measuring several metres, will replicate a folding wing in the fully extended position during a flight
So no, they are not foldable today - the headline submitted to HN is total clickbait.
- AFAICT they don't exist at all today. They are just renderings. So double clickbait. A more accurate title would be, "Airbus announces plans to develop foldable wing extensions, with non-foldable versions as the first step" or something like that.
- I mean the article is not lying about it only the title here, the title there is "Airbus launches new flight test programme for Wing of Tomorrow" and it's a press release for the start of a new program in their innovation area.
- "Airbus tests extended-length wings to see if it's worth developing the technology to produce folding versions of the same"
- No, they are not testing these wings in the present, they are planning to test them in the future:
"Over the next three years, Airbus will design, build and flight test full scale wing extensions."
- It looks like you can get ~10-20% efficiency gain from these kinds of wings. https://www.technologyreview.com/2013/11/18/175391/folding-w...
That's a meaningful improvement but not that big. Perhaps the limits to this kind of technology are ~50% fuel gain? https://www.technologyreview.com/2013/01/24/180345/hybrid-wi...
We've got AI, but I'm still waiting on exponential technological gains. So far I've mostly gotten exponential enshittification of my google experience. Is AI going to unlock the detonation engine and bring down the cost of my plane ticket? https://www.technologyreview.com/2012/11/23/181486/exploding...
- 20% efficiency means you can open single isle flights on 25% longer distances, which open a lot of routes that are not profitable with regular long haul planes.
I've flown on the A321LR a few times, and it's always crazy to think about that tiny plane cruising over the Atlantic without stops.
- 10-20% efficiency is enormous considering fuel is by far the dominant lifetime cost of operating an aircraft.
New fuels (SAF) and the technology to use them have been developed for less.
This is all to say nothing of the continuous work done over decades now to make aircraft more efficient; as these effects compound, intuition says that returns would start diminishing, so 10-20% is even more impressive.
- I agree. But is it about making the whole aircraft 20% more efficient or making the wings contribution to the whole aircraft’s performance more efficient?
- 20% would be an absolutely massive accomplishment. Think about how many decades of incremental improvement have gotten us to the efficiencies we have today.
- This is a massive improvement for airliners where margins are a few %. Tube and wing configuration is already highly optimized. This is a physical problem with a hard limit. Can you make a sphere "exponentially" rounder?
- The first paragraph of your comment is very informative. The rest, not so much. I highly suggest editing the rest out.
- No pics?
- Yeah that's uh, that's nothing. The orange part is supposed to be foldable somehow?
- My read is that they're announcing a plan to build non-folding wings to test the geometry they would eventually want with folding wings. Which makes sense but isn't very exciting.
- It's not just geometry, it's also where the mass is. And the rigid areas.
Aircraft wings oscillate during flight, the location (and movement) of mass within them (e.g. fuel) is critical to model.
Also, the location of the fold is likely less flexible (e.g. more rigid) than the remainder of the wing. This will greatly affect the dihedral angle of the remaining outboard portion of the wing.
- It begs for a video too!
- The headline is just clickbait, no such product exists to be videoed.
- What’s the purpose of doing this? (Site won’t load for me)
- My 2c:
The goal is longer, thinner wings than usual. Long and thin wings are far more efficient—think gliders and the U2. But beyond a certain width, those wings become incompatible with existing airports and other facilities for handling commercial aircraft. So the idea is to mount folding extensions that are extended for flight, but likely fold when being hangered or navigating taxiways.
- And, importantly, this programme is targetting the next generation of single-aisle aircraft.
It was hard enough to convince a few dozen of the world's largest airports to make the alterations needed to accommodate the A380's wings. Demanding similar changes at the thousands of smaller airports where A320-class planes land would be a non-starter.
- Ground infrastructure.
E.g. for the 777X it fits in Category E. Without folding tips it would be in Category F. Less gates can accommodate Category F.
https://skybrary.aero/articles/icao-aerodrome-reference-code
- > The Wing of Tomorrow programme is centred around creating longer, lighter, and more slender wings to maximise aerodynamic efficiency and reduce fuel burn. The wing extensions will be assembled at Airbus’ Wing Technology Development Centre in the UK and flight tested in Toulouse.
- An airliner weighs a certain amount. In cruising flight, the lift on the aircraft is exactly equal to the weight (because it's neither climbing nor descending). Aerodynamic drag falls into 3 buckets: parasitic drag, wave drag, and lift-induced drag. Lift-induced drag is drag created by the wings producing lift.
Longer, thinner wings (higher aspect ratios) create less lift-induced drag for a given wing area, so ideally you want a super duper long and skinny wing, which will create less drag for a given amount of lift, and thus improve your fuel efficiency. Fuel is a massive portion of the total cost of operating an airliner, so there is a large financial incentive from the airlines to reduce fuel costs.
Unfortunately really long wings make airliners too wide to park at most airport gates, and in some cases too wide to taxi safely around obstacles, so they're experimenting with ways to make the wings fold and get a "best of both worlds" situation.
- oh great now I have to worry about the wing tips flying off midflight as well
- Operation from aircraft carriers, obviously. /s
- >The Wing of Tomorrow programme is centred around creating longer, lighter, and more slender wings to maximise aerodynamic efficiency and reduce fuel burn. The wing extensions will be assembled at Airbus’ Wing Technology Development Centre in the UK and flight tested in Toulouse.
I can't say for certain, but I believe Boeing may have explored this concept at some point. The idea would be to equip aircraft with mechanically extendable wingtips that could expand outward by several meters during flight and retract while on the ground.
The primary challenge is that most airport gates cannot accommodate aircraft with a significantly larger wingspan. Retractable wingtips would allow the aircraft to benefit from the improved aerodynamic efficiency and fuel savings of a longer wing in flight, while still fitting within existing gate infrastructure during boarding, deplaning, and parking.
- Yeah, Boeing has the 777X that features folding wingtips. It still going certification and is looking like it'll be out next year (originally 2020).
- Military aircraft have done this for decades to deal with the confined space on aircraft carriers. It's not a new idea, nor any kind of new technology.
- Do you have any aircraft on mind that can unfold its wing while flying? (I'm aware of variable-sweep wing which can reconfigure in flight, or foldable wings that will be fold on the ground before parking).
- I don't see in that article that they are planning to unfold them in flight. There is mention that "In parallel, Airbus UpNext is accelerating the eXtra Performance WING demonstrator, focused on developing a wing that can change shape during flight" but that sounds like a separate project.
My guess is that they will be folded after landing, and unfolded prior to takeoff, as other planes with foldable wings do, so that they can continue to fit in standard spaces in the parking/gate areas.
- Yes this is on the 777x, which is in pre-production and flight testing, seeking approvals from the FAA
- Title: Airbus launches new flight test programme for Wing of Tomorrow
... doesn't look like there's any folding being tested here, just the resulting wing shape to see what the benefits might. Full scale foldable wings would be years off.
- You're right, it's a proof of concept: "The extensions, each measuring several metres, will replicate a folding wing in the fully extended position during a flight. They will be fitted with comprehensive testing equipment to capture behaviour in flight and evaluate how the longer wingspan impacts aircraft handling."
- Not just the shape, but also the mass placement and rigidity. I explain this in another comment, I don't want to cut and paste redundant info here but keep scrolling and you'll find it ))
- Orville Wright could have explained the reduced drag asociated with a higher aspect wing in 1902, perhaps useing his own terminology as airodynamics as a concept was still stuck in he and his brothers heads for the most part, but was very well known by 1910 and on up. Airbus should probably stick to structural engineering refinement, which they are rather good at, and not try and sell themselves as inovators, which they are not.
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- Cool, but Boeing is doing it first with the 777X.
- Let's hope, it doesn't fall off...
- don't worry, they are built with: "very rigorous ... [areospace] engineering standards."
- Cool, but then you'd be forced to fly on a Boeing.
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- Foldable wings have been on aircraft carriers for a while as well.
