aeroturbopower
The blog about aeroengines and what they power
1/15/2023
Bavarian Airlines! Bavarian... What???
6/04/2021
Boeing's big gamble
A recent article by Bloomberg about the new composite wing that could replace the current wing on the A320neo, a project called “The Wing of Tomorrow” by Airbus, spurred some discussions about the future Airbus narrowbody product line and how Boeing would/could react.
The subject, as
Scott Hamilton writes, is not new at all. I heard about it in 2013 for the first
time. Airbus at that time thought that Bombardier would launch a CS500 (today
discussed as the A220-500) and thought that the CS300 was about 5% better in
economics than even advertised by Bombardier to customers. This gives us a first indication of how good an A220-500 could be, as the A220-300 has at least the same
costs per seat than the A320neo, if not better. A stretched aircraft always
tends to have better seat costs than the original one, so the A220-500 has better
seat mile costs than the A320neo “by definition”.
If the A220-500 it would be an
A320neo and B737-8 killer, as Scott Hamilton thinks, is another question though
and depends on how the A220-500 exactly would look like and what the mission is
an airline is looking for.
Start with the current
payload-range diagrams of the A320neo and the A220-300.
Looking at the payload-range
diagram we see that indeed with 165 x 220lbs per passenger = 33klbs of payload
the range is in the 3400nm range.
The payload-range diagram of
the A220-300 is not yet updated by Airbus (at least not for the “flying public”)
and still shows around 3100nm range with 140 passengers and 149000lbf MTOW. If
we believe in the Airbus
claim that with the new MTOW of 156000lb range would be 3550nm we get the
new range-payload line approximately as a parallel line to the old one. Now let
us seat 165 in that aircraft (knowing that it would not work of course) and we
see that range would fall to around 3000nm by the addition of the extra 25
passengers of payload.
To seat these 25 passenger we
would need to stretch the aircraft by five rows of about 4m of 13ft. This is
about the same difference in length than between the A220-100 and the A220-300.
For simplicity, let us
consider that the difference in OEW between the A220-300 and a potential A220-500
with unchanged MTOW would be same as the difference between the OEW of the
A22-100 and the A220-300: 4100lb. Then we would get a range of the stretched A220-500
aircraft of around 2500nm.
On one hand, this is enough
for probably around 95% of all flight a A320neo of a B737-8 is used for today.
On the other hand, flexibility is key for many airlines, so the limited range
of an A220-500 would be a problem for many airlines.
Now we can increase the MTOW
of the A220-500 to increase range.
Start with a comparison of the
wing loading: the A220 wing has 112.3 square meter, the A320neo 122.6. To get
to same wing loading we could increase the MTOW of the A220-500 by about 3500lb.
This would increase the range by approximately 300nm to about 2800nm. The original
CS300 was advertised with this range. With the same wing loading and the same
generation of engines, especially with a bypass ratio that is in the same range,
runway characteristics should be comparable as well then.
So would the A220-500 be a A320neo and B737-8 killer? If you definitely do not need more range than 2800nm it could be.
For Airbus, with their “Wing
of Tomorrow”, this would not be such a big problem. They could do the
A320.5neo++ (or whatever it will be called). For Boeing, not having a competitive
product against the A220-100 and -300 to begin with, the A220-500, together
with a A320.5, could turn into a bigger problem. Both aircraft would squeeze
the B737-8 from both above and below, the A320.5 with better range and economics
and the A220-500 with dramatically better economics.
But the ball is in Boeings court.
As it looks, they have to move first, either with an aircraft that aims at
the so called Middle of the Market, that is now captured by the A321XLR, but
leaving the B737-8 alone. Or by replacing the MAX family soon, which could counter
an A220-500 on the low end but leaving the A321XLR and even more a potential
A322 alone on the playground.
Canceling the joint venture
with Embraer could have been a big failure going forward, as “Boeing Brazil”
could have worked on the lower end of the narrowbody product line.
Disclaimer: these thoughts are just easy considerations without going through all the (engineering) steps necessary. But it gives us a hint where the different aircraft are relative to each other.
4/05/2021
5X – what 5X?
During the last weeks Aviation Week had a few articles (here and here) about an alleged new Boeing widebody aircraft code-named -5X. More or less a NMA reloaded, this aircraft would be targeting the A330neo family, but in turn as well the 787-8/9.
Stop –say what? The 787 is right now not selling like
hot cakes, but the A330neo not as well and the main reason is COVID-19,
although also without the pandemic both aircraft would see lower production
rates today than until 2019. So where is the point in developing a new aircraft
there? The NMA, which was not able to produce a business case for Boeing, was
shelved and was probably almost the same aircraft. Part of the problem back
then was that the engine companies did not see the market as attractive as
Boeing (officially) did and both CFMI and P&WA only wanted to develop an
engine as a sole source.
So where is the reason to believe that now, two years
later, it actually looks better for an aircraft like this?
The only thing Boeing should concentrate on is a new
Single Aisle aircraft family! If Boeing would start an aircraft like -5X now
with an EIS not before 2027, themselves as well as the engine companies would
not have the resources to be able to counter an A320neo++ family with a new
wing and engines that will then get a performance improvement package from the
-5X engine(s). Also, as Scott Hamilton from Leeham writes today, the A220-500 is only a question of when, not if. So the lower end of the B737MAX would get increasing pressure once the - 500 is on the market. The B737MAX would be dead then, "killed" from the A220-550 from the lower end and from the A320neo++ and A321neo++ from the upper end – and in turn BCA would be dead!
But is it possible to design an aircraft family that can compete with the A220-500 on the lower end and a future (possible) A322? No, but the Airbus narrowbody aircraft family has two wings, two fuselages and different engines as well. So a clever scaling of the fuselage and the wings could do the trick for Boeing. Starting with the larger (6 abreast) family, starting just north of today's 737MAX-8 up to a A322 sized aircraft. After that scaling fuselage and wings down to a 5 abreast aircraft with a second or third generation of the PW1500G for example.
Just my 2 cents of course - but I see less than these 2 cents of value in a -5X!
12/27/2020
GE and the Geared Turbofan
There was quite a lot of hype in the last days around a story, first reported by Bloomberg, saying that GE talked with Airbus about a new engine for “a narrow-body jetliner in development”. In the article (and many that followed that first story) there is a lot of speculation about the aircraft: If it would be a successor of today's A320, a future stretched variant of the A220 or if that aircraft would in the end be the ZERO E (E for Emissions) aircraft announced by Airbus in September and the engine GE and Airbus discuss here would be an engine that would be used for that aircraft until a ZERO E engine (technology) would be available.
To make it
short: this last consideration is – sorry to say it that way – bullshit!
Whatever the source of energy of the future ZERO E aircraft would be – hydrogen
or electricity comes to mind- the aircraft has to look very different from the
design of a jet fuel powered aircraft and it would make no sense at all to hang
a Geared Turbofan on an aircraft designed and optimized for zero emissions.
The fact
that GE and Airbus talk about a new narrowbody is not a big story in the first
place, as there are always discussions between airframers and engine companies
about all kinds of possible future projects. But Bloomberg made a lot of noise
due to the fact, that the design proposed by GE would be a geared turbofan,
which is the engine design that today only Pratt & Whitney uses. GE always more
or less dismissed the geared design in public because of the added complexity
of the gear. Rolls Royce began developing their own geared engine concept
called Ultrafan a few years ago.
So does GE
not believe in the conventional turbofan anymore?
Not
necessarily: believe it or not, but it is not the first time that GE proposes a
geared design to an aircraft manufacturer. For the B777X, today's B777-9, GE
also pitched a geared design towards Boeing, as did P&W at that time (I
believe RR proposed a 3 spool design). But obviously Boeing went down the low-risk
path of the GE9X engine, an evolution of the GE90-115B and the GENx engines,
although the geared engines would have had a better fuel burn.
For the now
(forever?) dormant NMA, Boeings reference engine was a geared turbofan. This
makes sense, as at least in the beginning two of the three possible engine
provider offered a geared design (P&W and RR), so we can only guess that GE
(or CFM) also offered both variants (geared and non-geared) to Boeing. Later RR
went out of the discussions as the aimed EIS timing was too early for the UltraFan.
So when today GE talks with Airbus about a geared engine, there is nothing sensational in there. Most likely the geared engine is just one out of two or more designs. And it most likely not more than a paper study, in which P&W and RR are involved as well. It is not more than the usual business of the future concept groups of all parties involved.
So do not expect an announcement of a new aircraft in the
near future. Even a stretched A220 (-500) seems not to be on the horizon too soon...