Leeham News and Analysis
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Leeham News and Analysis
- Bjorn’s Corner: New engine development. Part 5. Turbofan design problems April 26, 2024
- Airbus 1Q2024 results: Airbus CEO: “A350 in-service experience drives positive reputation and orders” April 25, 2024
- A350-1000 or 777-9? Part 3 April 25, 2024
- Boeing CEO promises company is turning around…again April 24, 2024
- Solid start for stand-alone GE Aerospace despite cuts to LEAP output April 23, 2024
Bjorn’s Corner: New aircraft technologies. Part 3. Airframe improvements
By Bjorn Fehrm
March 10, 2023, ©. Leeham News: Last week, we could see that the best investment in new aircraft technology would be for the replacement of the single-aisle segment, where the Airbus A320 series and Boeing 737 MAX are the players.
If we can make this segment more efficient, we will improve the economics and emissions from this aircraft class. The detailed discussion is done in a sister article, New aircraft technologies. Part 3P. This is a summary of this article.
Figure 1. The Airbus A321 delivery to jetBlue, part of the aircraft segment that is up for replacement. Source: Airbus.
Replacing the single-aisle segment
The first thing we could see was that naming the segment as “Single aisle” or “Narrowbody” is a bad choice. It directs our thinking into a certain aircraft type even before we have defined the requirements of the segment.
When we look at the time it takes to develop a new aircraft and get it into the market, and then over what time period it shall be delivered, the choice of aircraft type is less clear.
What we know is:
- We want the aircraft to cover the “heart of the market,” i.e., the segment where the most aircraft are sold and delivered during the project’s delivery period.
- If you study the historical changes of the “heart of the market,” you conclude that the least of our airframe problems is whether the aircraft has a truss braced wing or not. The acute problem is what aircraft type shall we develop?
- Our new aircraft, with its 40 years of active life (the A320 is on its 35th, the 737 on its 56th), morphs from a maxed-out single-aisle plane into a dual aisle almost irrespective of what movement theory we have on the “heart of the market.”
Figure 2. The heart of the market five years ago, the Boeing 737-800. Source; Beoing.
So the first thing to do is to understand the fundamental requirements of a next-generation “heart of the market” aircraft. It’s not whether it has some new wing configuration or a different propulsion system.
It’s what aircraft type do we develop? Do we think the “heart of the market” will move less than over the last decades? In such a case, is a new, more efficient, single aisle the right aircraft?
Or, if the market moves at the present pace, can then a dual aisle plane be as efficient as a single aisle?
The 3P article put numbers to this discussion, defined the base specification points of the new aircraft, and decided what the next steps are.
Airbus thought the A300 would replace 2ea 150 seat aircrafts on the same routes and become the heart of the market. The A300 could not take the cycling. So today we see A321’s taking that role. In theory could a 300pax twin aile UDF powered aircraft do it. But much cheaper to do the A322 with 5-6 more rows and a new wing than the A321.
Bjorn says the configuration (cross section, wings) is a result of the requirements. I agree, however those requirements often include investment costs/ subsidies, existing portfolio, time to market, keeping up free cash flow.. etc. Non technical requirements..
Agree with Claes a reasonable A322NEO (the XLR wing / 102t MTOW seems good enough) is hanging over the market & probably making Boeing shy.
The heart of the market seems 199 seats single class <1000Nm for the coming years. It seems hard to make a twin aisle a good idea for that. Maybe fast (de)boarding is falling down the priority list.
I tried something years ago, ECR-20. (aimed at EIS 2020..)
https://www.pprune.org/tech-log/445308-ecr-20-200-seater-optimized-flights-700-nm.html
For the imaginary airline Tianjin Express, visualized by Henry Lam 2011. https://www.flickr.com/photos/rtm67/34915184323
Airbus could do the A300 again with 2023 technology and new engines, but an A322 with new carbon wing and existing engines with maybe a 1-2″ increase in fan diameter would be very hard to beat cost/performance wise. Boeing had the 787-3 for this market but it is too expensive. Can it be made cheaper than an A322? You need great design and production engineers to have robots build the 797 cheaper.
A new wing (and its new supply chain, infrastructure) for A321 would cost maybe E5B and 5-7 years. IMO it’s questionable if the benefits would be big enough to justify that investment & lead time over the upgraded A321XLR wing (new flaps system etc). The Wing of the Future project seemed to focus on costs..
https://www.flightglobal.com/airframers/cost-reduction-central-to-airbus-future-wing-programme/132676.article
A carbon wing has several benefits, the CRFP is stiffer and lighter than aluminum alloys making a longer and thinner wing possible. Airbus most likely has one design but it must be designed to be produced with robots quickly and economically with high quality preferrably out of autoclave. That is an even bigger job and with Airbus wing production spread over Europe it is a major coordination to get it working well at all sites.
The 787-3 was an optimized as possible 787 for the Japan market. No one else had any orders for it.
Japan will fly an A350 on a two hour route. That is because they are broken into 5 main Islands and its the only market like it in the world. They have flown 747s on those same routes.
The airlines clearly want a Swiss army knife aircraft for the current single aisle market that do ridiculous 200 miles flights to they can make longer ones as needed or deemed efficient use of a route.
Some airlines do use wide body for trans continental routes US, I don’t follow routes in Europe though US also is a mix of single aisles.
Alaska Airlines is something of a classic case in that they prefer frequency over a single large load in say a 767 from Anchorage to Seattle as well as Seattle to SFO or LA.
Economics say the cost of a single aisle is a lot less than a wide body so they use single aisle as much as possible.
So far aerodynamics have not been able to overcome that hurtle.
I have to correct that. Airbus sold a regional A330 into China but that is a different market with airspace restrictions you don’t normally see in other countries (China Military owns and control’s all airspace). While Airbus sold some it was not a major one that spread anywhere else.
https://www.airbus.com/en/newsroom/press-releases/2016-08-airbus-delivers-worlds-first-a330-300-regional-to-saudi-arabian
They bought 20
‘The A330-300 Regional is optimized for missions up to 2,700 nm (5-hour flight) covering short to medium haul routes and offers significant cost savings through a reduced operational weight of around 200 tons. The reduction in fuel burn per seat and maintenance costs will result in an overall cost reduction of around 20% compared with today’s long-range A330-300. ‘
Airbus wings arent ‘spread all over Europe’. They are mostly from one location in North East Wales – Broughton a former De Havilland site where they made Tridents but now owned by Airbus. They like to keep the technology in house . The A320 series metal wings are mostly in Asia now but some parts in Europe too such as Prestwick
The A220 wing is made outside Belfast
@Duke. I mean the fully stuffed wings ready for installation. Just look at the A350 wing which countries all has been
IIRC, the A330R was a pure paperwork exercise. all they did was lower the paper MTOW and max fuel volume certification of the baseline A330 to restrict the range and weight, then dropped the price a bit.
a buyer could, at a later date pay for the “upgrade” to full A330 capability which consisted of Airbus updating their database and printing a new cert.
A330 is the case in point as while it was 20% more efficient than a non A330R, it was no where near as good as a single aisle.
The hull and wing has to be as light as a single aisle and Boeing is not confident they can do that at the price they need to.
For clarity, Airbus Wing Production is mostly centred on Broughton, UK with Assembly for A320, A330, A350.
A400M is assembled in Filton, UK.
The wings for A320s delivered in China FAL are assembled in China.
The sub-components come from all over the world. This includes the lower wing covers for A350 coming from Getafe, Spain, upper covers from Stade, Germany. Also includes A320 skins coming from Korea for example.
I disagree. The a322 is not a good plane, and with certification requirements would be a waste of money as Boeing has to come out with a new design. The cost would be significant and still be layered atop 80s tech. This would sell as well as the a350 mk1. A short range 200 seater sounds Mercure-esque. Airlines like flexibility, that is the antithesis of it.
Airlines, and passengers love frequency when flying
For most continental, medium-haul destinations in the US and Europe, a 200 seat aircraft is perfect
Narrow body aircraft’s boarding, is usually done using only 1 door
This slows down the process, specially in aircraft with more than 130 seats
And is delayed because passengers can’t find room for their luggage
Airlines love small wide-body aircraft, to fly medium-haul destinations
Boarding and disembarking is super-fast
Airlines can offer a better in-flight service
And passengers love them
I remember way back in the ’90’s telling Airbus sales that what I really wanted was a 150 seat, swept wing turbo-prop.
That’s a nice concept. Of course, it needs to be a 200 PAX in today’s market.
Boarding time is essential, in today’s Commercial Aviation
Super-fast turnovers are very common now
Airlines do not want to see their planes idle at the airports
Wide-body aircrafts, are loved by passengers, and crew
They offer fast boarding and disembark
And there is always enough space for all hand luggage
I don’t think something like a widebody would be efficient for this Heart of the market.
Keesje, your concepts are
generally interesting
But for this one (IMHO) if it would have been a narrowbody it would have been more efficient.
Checklist probably. Consideration were it to be more compact (shorter fuselage) and providing 2 aisles (and rooftop windows) to compensate somewhat for the high passenger density (24 inch pitch).
“Standing” seats were discussed/ offered at that time, by Avio.
Years before I took a single aisle “Turboliner” probanly more feasible,as you mention. https://flic.kr/p/WqSM6a
Rooftop windows are a non starter as it has huge structural impacts.
I think windows are overrated, many passengers just pull the shade down and play with their phones or go to sleep.
No one wants to risk being wrong though.
virtual windows are they way to go in future aircraft. lighter weight, easier maintenance, one less thing that could scuttle a flight, and would allow infinite choice of viewing options to the passenger.
slap 15 webcam quality cameras in various locations on the airframe and add a choice of views that are not where the plane is, like flying past Olympus Mons on Mars half way through the Red Mars/Green Mars/Blue Mars trilogy…
In the picture you can see “4 roof top windows replacing 20% side windows”.
The concept was to spread natural light in the middle of the cabin, for all passengers, to compensate a reduced number of side windows.
Saving weight & costs.
It is a good design – I would have bought it. For me, you would have to benchmark it against the Vickers Vanguard (an upgraded 250PAX version) a much under rated aircraft.
We, Humans need a real point of reference, that connects us to reality
Many passengers are afraid of flying
Most are under some level of stress
I do not think virtual windows will work
Virtual windows will work—if properly done. We Humans also have minds that are remarkably pliable and supported by powers of perception that are sufficiently flawed that we will believe almost anything presented to our senses, provided the false sensation is of adequate quality and properly engineered to take advantage of the frailties of Humans. Quality is the degree of indistinguishability that an artificial stimulus has from the real thing, and yes, we have reached that level of quality even in the most mundane areas of life. Have you ever turned your head because some sound off to the side grabbed your attention, and then realized that the sound was from the movie you were watching with Surround Sound audio? Likewise if you leaned to one side to look at something just around the corner, then realized the “corner” was the edge of the large screen 4K video monitor on which you were watching a high-def movie. On a more esoteric application, consider: We use flight simulators to present false aural, visual and tactile sensations to pilots to convincingly give them the impression that they have accelerated from a standstill to 500 knots while climbing from sea level to above—and around or bumpily through—cumulonimbus clouds topping out at 25,000 ft… all while, in reality, their “flight deck” cab movement has been confined to linear motion of no more than a couple dozen feet in each axis of a cubic 3D space and rotation of no more than 20°-30° around any axis. And paradoxically, while using sensory illusions to trick their minds thusly, we successfully train them to focus on the instruments and ignore the somatogravic, somatogyral and other sensory illusions that can be produced while “flying” in IMC! (Pilots are so easily fooled, aren’t they? 😬)
Is making a comment the only way to get notifications by email about new posts and comments?
Looking at what GE/Safran plublished last year, as configuration concepts for their high BPR open rotor RISE project, the one left looks familiar.
High wing mounted engines / T-tail still seems hard to beat, 100 yrs after.
https://aviationweek.com/sites/default/files/styles/crop_freeform/public/inline-images/ROTOR-3_CFM.jpg?itok=BHAUX9_B
completely ignores the overwing pusher (aka hondajet) configuration which allows you to keep the good things of low wing (structural and aero benefits, shorter landing gear, short rescue ramps, easy access to wing for maintenance) without restricting fan diameter
Overwing pushers proved horribly noisy, because of wing strut / wing wake hitting the fan.
pusher: https://youtu.be/3i-eXapGDgk
puller: https://www.youtube.com/watch?v=eesx39qLHkY&t=15s
No wonder Embraer moves to a puller, even for their tail mounted designs.
Still engines on the wing are generally better weight distribution. Once I looked at a 100 seater, staggered 5 abreast, with lower overwing pullers. A bit like an il-114.
https://live.staticflickr.com/4010/34915205183_6745aedfb0_z.jpg
The Honda Jet could get away with it but not on a bigger jet.
Engines in the tail, Turbo Prop or not are a none starter.
The wings have to both support rear engine weight and structural has to deal with it.
> Engines in the tail, Turbo Prop or not are a none starter.
The wings have to both support rear engine weight and structural has to deal with it. <
oh.
the engines are on the wing, not the tail in the honda jet. what are you talking about.
those two videos are comparing apples to elephants.
one is a high speed flyby from a side angle at high throttle setting, the other is a forward angle of a plane idling during landing from the front.
also you have no info on camera and mic distance, volume levels or anything.
those videos are meaningless.
You had to rewind a bit earlier in that video, the low pass 😉
https://youtu.be/eesx39qLHkY
It’s all about he wake of wings, struts hitting the fan. If you have a home ventilator, blow against it from close by. A lot of research was done of many years to reduce this, to minimize/ compensate the wake, avoiding the (irritating) noise.
Embraer R&D recently called it a day and went for pullers..
https://d2n4wb9orp1vta.cloudfront.net/cms/brand/CW/2021-CW/1112-cw-news-embraer-energia-opener.jpg