The main goal of the investment would be a carbon-neutral successor to the A320, Europe's best-selling jet, with hydrogen as an energy source instead of today's oil-based gas turbines. "Our target is to have a carbon-neutral airplane in 2035 instead of 2050, thanks especially to an (ultra-efficient) engine using hydrogen," Le Maire said.

Dieuwer wrote:

The main goal of the investment would be a carbon-neutral successor to the A320, Europe's best-selling jet, with hydrogen as an energy source instead of today's oil-based gas turbines. "Our target is to have a carbon-neutral airplane in 2035 instead of 2050, thanks especially to an (ultra-efficient) engine using hydrogen," Le Maire said.

Hindenburg 2.0

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop?
Since when do governments know which products are good for companies?
I really hope this plan hasn't been finalized yet and that the German and Spanish governments will kill it.

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop?
Since when do governments know which products are good for companies?
I really hope this plan hasn't been finalized yet and that the German and Spanish governments will kill it.

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop? Since when do governments know which products are good for companies?

lightsaber wrote:

[...]I wish them well, but [...]

Kilopond wrote:

lightsaber wrote:

[...]I wish them well, but [...]

... the crappy texts do not really say what it is all about: namely, operating hydrogen-based fuel cells with H2 tanks at a pressure of 700 bar which means the energy density is quite high. The pressure is expected to rise even higher to well over 1,000 atmospheres in the future.

At filling stations, 700 bar H2 has come down to € 9.50 per kg from € 14.00 within a few months.

https://h2.live/en

Dieuwer wrote:

aka a flying bomb.

armagnac2010 wrote:

Hindenburg used hydrogen for its low weight, in gaseous state. Indeed, liquid hydrogen is much safer to store than kerosene. Remember TWA800?

mxaxai wrote:

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop?
Since when do governments know which products are good for companies?
I really hope this plan hasn't been finalized yet and that the German and Spanish governments will kill it.

The German and Spanish governments will do their best to support this plan. This is exactly in line with their own goals.

The Government is simply giving Airbus (and suppliers) money to conduct fundamental research on new, promising technologies. Hydrogen is just one aspect. Other projects aim for even more lightweight construction methods, improved manufacturing techniques, future operational concepts and other measures that provide a long-term improvement to the industry. Nobody is 'dictating Airbus which planes to develop'.

Devilfish wrote:

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop? Since when do governments know which products are good for companies?

Since companies began asking governments for funding to develop new technology

Aesma wrote:

I don't know who came up with this (not Le Maire as he's a literature guy, not an engineer), however H2 fuel might make sense for long haul aircraft, not short haul ones. Worse, they mentioned 500Km long flights, but at the same time are trying to ban such short flights !

For 500Km hybrid/electric is the way. But I'm not sure there is a market, outside island countries maybe.

Aesma wrote:

I think what matters is "carbon neutral". Let the smart people figure out the best way to do it. Might need 10 times more billions, though.

It may be that for aviation the best way is synfuel made from electricity, heat, water and atmospheric CO2, with H2 as an intermediary.

Jetport wrote:

https://finance.yahoo.com/news/france-bets-green-plane-package-131648673.html

Surprised no one has started this thread. Merge if I missed it.

enilria wrote:

Jetport wrote:

https://finance.yahoo.com/news/france-bets-green-plane-package-131648673.html

Surprised no one has started this thread. Merge if I missed it.

Cue Boeing and USA trade lawsuits.

planecane wrote:

Also, while H2 would eliminate CO2 it would put out a lot more water vapor at high altitude, whether used in turbines or fuel cells. Not sure what impact that would have.

Hydrogen has an energy content of 122.8 MJ/kg and a density of 70.8 kg/m3 in liquid state.

A typical energy content for kerosene is 42.8 MJ/kg¸ its density lies between 775 kg/m3 and 840 kg/m3 at 15 °C

The combustion of 1 kg of hydrogen produces 9 kg of water vapor [...]

The combustion of 1 kg of kerosene uses 3.4 kg of aerial oxygen and produces 3.15 kg of carbon dioxide (CO2), 1.25 kg of water vapor (H2O) [...]

Hence, compared to the energy content of 1 kg of kerosene, the combustion of an energy-equivalent amount of hydrogen generates only 3.24 kg of water vapor [...]

The hydrogen propeller variant consumes less energy than the kerosene aircraft in an order of 5 %, and it is more environmentally friendly due to its significantly lower emissions (no carbon dioxide, 90 % less nitrogen oxides, more water but no contrails). Of course, an overall environmental benefit is highly depending on the way the hydrogen is produced.

Aesma wrote:

It may be that for aviation the best way is synfuel made from electricity, heat, water and atmospheric CO2, with H2 as an intermediary.

FluidFlow wrote:

The article states:

The hydrogen propeller variant consumes less energy than the kerosene aircraft in an order of 5 %, and it is more environmentally friendly due to its significantly lower emissions (no carbon dioxide, 90 % less nitrogen oxides, more water but no contrails). Of course, an overall environmental benefit is highly depending on the way the hydrogen is produced.

So for a bit more than double the water vapor you have 0 carbon dioxide and 90% less NOx.

So i do not think it is a lot more water, just more water.

mxaxai wrote:

Aesma wrote:

It may be that for aviation the best way is synfuel made from electricity, heat, water and atmospheric CO2, with H2 as an intermediary.

Synthetic fuels are not really viable. Filtering atmospheric CO2 is a lot of work due to its low concentration. It'd be easier to distill ocean water and convert it to hydrogen. As of today, the cost for automotive fuels is staggered as: fossile < electricity < biofuels < hydrogen < synfuels.

FluidFlow wrote:

The article states:

The hydrogen propeller variant consumes less energy than the kerosene aircraft in an order of 5 %, and it is more environmentally friendly due to its significantly lower emissions (no carbon dioxide, 90 % less nitrogen oxides, more water but no contrails). Of course, an overall environmental benefit is highly depending on the way the hydrogen is produced.

So for a bit more than double the water vapor you have 0 carbon dioxide and 90% less NOx.

So i do not think it is a lot more water, just more water.

The study focuses on a propeller aircraft at lower altitudes (6-8 km), so 'no contrails' would not hold true once you get to typical jet cruising altitudes.

Moreover, in the special case of the here regarded regional aircraft, the water vapor emissions have a smaller climate impact than those of longer range aircraft due to the relatively low cruise altitude of less than 8 km. Contrails usually only form above this altitude

enilria wrote:

Jetport wrote:

https://finance.yahoo.com/news/france-bets-green-plane-package-131648673.html

Surprised no one has started this thread. Merge if I missed it.

Cue Boeing and USA trade lawsuits.

lugie wrote:

Aesma wrote:

I don't know who came up with this (not Le Maire as he's a literature guy, not an engineer), however H2 fuel might make sense for long haul aircraft, not short haul ones. Worse, they mentioned 500Km long flights, but at the same time are trying to ban such short flights !

For 500Km hybrid/electric is the way. But I'm not sure there is a market, outside island countries maybe.

Well they are banning such short flights right now when they're operated by emission-intensive fossil fuelled jet engines.

I don't think that anybody would be opposed to flying even short distance if such flights were operated by entirely carbon-neutral and emission-free H2 planes.

Such a ban will likely be reversed if(when) this technology sees the light of the day and is applied by airlines on a significant scale.

Jetport wrote:

lugie wrote:

Aesma wrote:

I don't know who came up with this (not Le Maire as he's a literature guy, not an engineer), however H2 fuel might make sense for long haul aircraft, not short haul ones. Worse, they mentioned 500Km long flights, but at the same time are trying to ban such short flights !

For 500Km hybrid/electric is the way. But I'm not sure there is a market, outside island countries maybe.

Well they are banning such short flights right now when they're operated by emission-intensive fossil fuelled jet engines.

I don't think that anybody would be opposed to flying even short distance if such flights were operated by entirely carbon-neutral and emission-free H2 planes.

Such a ban will likely be reversed if(when) this technology sees the light of the day and is applied by airlines on a significant scale.

Electric, Hydrogen and Hybrid aircraft are just silly. The energy density/kg in usable systems for aircraft of hydrogen and/or batteries is just too low. Kerosene is much too energy dense/kg in a usable system for aircraft to replace with anything in the foreseeable future. If you want to make aviation carbon neutral, use offsets or sequestration, it will be much cheaper than hydrogen or electric aircraft. Banning short flights will also cost lives. Air transport is safer than rail and far safer than auto or bus transport.

Noshow wrote:

Didn't they just cancel their electric Avro demonstrator?

VV wrote:

I think it is a good thing, especially if the fund is used to define products in a pragmatic way and is not driven by an ideology toward targets that are not achievable.

Jetport wrote:

lugie wrote:

Aesma wrote:

I don't know who came up with this (not Le Maire as he's a literature guy, not an engineer), however H2 fuel might make sense for long haul aircraft, not short haul ones. Worse, they mentioned 500Km long flights, but at the same time are trying to ban such short flights !

For 500Km hybrid/electric is the way. But I'm not sure there is a market, outside island countries maybe.

Well they are banning such short flights right now when they're operated by emission-intensive fossil fuelled jet engines.

I don't think that anybody would be opposed to flying even short distance if such flights were operated by entirely carbon-neutral and emission-free H2 planes.

Such a ban will likely be reversed if(when) this technology sees the light of the day and is applied by airlines on a significant scale.

Electric, Hydrogen and Hybrid aircraft are just silly. The energy density/kg in usable systems for aircraft of hydrogen and/or batteries is just too low. Kerosene is much too energy dense/kg in a usable system for aircraft to replace with anything in the foreseeable future. If you want to make aviation carbon neutral, use offsets or sequestration, it will be much cheaper than hydrogen or electric aircraft. Banning short flights will also cost lives. Air transport is safer than rail and far safer than auto or bus transport.

Baldr wrote:

VV wrote:

I think it is a good thing, especially if the fund is used to define products in a pragmatic way and is not driven by an ideology toward targets that are not achievable.

"pragmatic": ???

"ideology": ???

"not achievable": IMJ, The EIS of a LH2-powered airliner is achievable by 2035.

Baldr wrote:

VV wrote:

I think it is a good thing, especially if the fund is used to define products in a pragmatic way and is not driven by an ideology toward targets that are not achievable.

"pragmatic": ???

"ideology": ???

"not achievable": IMJ, The EIS of a LH2-powered airliner is achievable by 2035.

lightsaber wrote:

Baldr wrote:

VV wrote:

I think it is a good thing, especially if the fund is used to define products in a pragmatic way and is not driven by an ideology toward targets that are not achievable.

"pragmatic": ???

"ideology": ???

"not achievable": IMJ, The EIS of a LH2-powered airliner is achievable by 2035.

As someone who has designed aircraft parts and currently in Integration and Test, I think 2035 is aggressive as engine technology I worked on in 1998 to 2001, entered service in 2016 and that was evolutionary technology. Fuel systems, when finished, seem simple, but gas fuel systems are so much more complicated than liquid and how is the fuel injector cooling being resolved? Liquid (fuel) cooling is far more effective than gas cooling.

Certification is far more involved today than 20 years ago. Everything going into commercial aircraft today, I can usually tell you some people who worked on the technology prior to 2000 that is in commercial aircraft. The exception being 3D printing.

In 2000, hydrogen was just grad student papers.

Lightsaber

3.1 Propulsion Chain

The concept of a turboelectric propulsion system consists of a gas turbine, generator and electric motor driving two contra-rotating propellers. The two CRORs are used as propulsors, whereas the gas turbine is solely used to produce shaft power. The power generated by the turboshaft is transformed into electric energy through a high temperature superconducting (HTS) generator. The coupling between generator and electric motor acts as electric transmission, which allows both the gas turbine and the CRORs to run at their respective optimum speeds. Electrical cross-wiring between the generators and the electric motors, as seen in figure 3.1, enables all electric motors to continue to operate in case of a generator or gas turbine failure. To maintain the same speed ratio of electric motors and gas turbine, the variable-pitch propeller decreases the power loading at the same speed to match the reduced power provided by the remaining gas turbine.

Gas Turbine

Present gas turbine cycles reach their limits when it comes to an improvement of energy efficiency or thrust specific fuel consumption (TSFC) along with a reduction of NOx emission. Designing a gas turbine at high load levels for best core efficiencies causes high cycle temperatures. Parametric optimization of a two-spool turboshaft in GasTurb 13 shows, that high cycle temperatures require high overall pressure ratios (OPR) to attain best core efficiencies. An optimization of TSFC therefore pushes the formation of NOx, as formation mechanisms show an exponential dependency on cycle temperatures [8]. New gas turbine concepts are currently under investigation by numerous research centres and industrial partners. Regarding the 2045 time frame of Polaris, the intercooled recuperative aero engine (IRA) concept shows the most promising cycle technology [9]. Intercooling reduces the specific power demand of the high pressure compressor (HPC), as the mass flow is cooled down between compressor stages. The work needed by the HPC to enhance OPR is decreased as the temperature at its entry is falling [10]. Recuperation benefits from increasing spread in temperature between exhaust mass flow and compressor mass flow, thus enabling higher temperature levels in the combustion chamber without manipulating fuel flow [10]. IRA cycles show the ability of higher core efficiencies for an OPR of up to 40, see figure 3.2. As part of the project "Revolutionäre Arbeitsprozesse" (RE-VAP), multiple IRA cycles have been investigated using the key technologies intercooling, recuperation, isochoric combustion with a wave rotor or pulse detonation and sequential combustion [12]. They concluded, that intercooling and recuperation enables the thermal efficiency to increase by 7%-13% to the baseline of ηth,baseline = 42 % [12] for an overall engine. Although isochoric combustion may lead to even higher thermal efficiencies, this technology is neglected in the design process as there is insufficient performance simulation and poor knowledge about its negative impact on turbine behaviour due to unsteady exit conditions [13]. Contrary to the estimated values of the bare IRA cycle, presented in figure 3.2, these thermal efficiencies are calculated using a tailored engine model. This model is taking losses due to propulsor, component cooling and minimum tip height into account. For a more realistic assessment of gas turbine efficiencies, the following calculations will consider the values as concluded by REVAP.. As part of the program, an optimization of the IRA cycle performed by TU Dresden proved thermal efficiencies of ηth = 50.8 % for a moderate OPR of 40 and 1590 K TET. Reaching equal thermal efficiencies for a conventional Joule cycle, requires an OPR of 99 and 2000 K TET [14]. New combustion technology and the reduction of OPR and TET are main drivers for low NOx combustion [8]. Employing IRA into the Polaris concept yields some additional advantages regarding intercooler technology. Using LH2 as coolant exhibits high efficiencies of the intercooler, allowing its surfaces to be minimised. Intercooling during critical operating conditions, such as take-off and climb, remains possible with a LH2 cool- ing architecture, where otherwise the cooling air mass flow for conventional bypass architectures might not be sufficiently provided. More synergies are found regarding the reduction of bleed air temperature, therefore optimizing the cooling of hot components and simultaneously enabling a reduction of bleed air mass flow which raises core efficiency [10].

Superconducting Technology

Cycle studies during the REVAP program proved the necessity of a separation of propulsor and power generation if engine architecture shall be optimized - which is therefore realized in the Polaris concept. As described above, decoupling the rotational speeds of gas turbine and propellers allows them to run in their respective optimum, as generator and electric motor are acting as “electrical gearbox” [15]. Furthermore, a turboelectric architecture enables an independent positioning of propulsion chain components. Incorporating conventional systems in turboelectric propulsion chain architecture is not practical for the Polaris concept, as power densities of electric motors and generators are too low; but superconducting technology becomes a key enabler for these systems [16], see figure 3.3. Moreover, using liquid hydrogen both as propellant and coolant for superconducting wires, cooling is practically free because liquid hydrogen must be evaporated before being burnt. HTS technology, discovered in 1986, exhibits high current densities at very low resistance. Fully superconducting machine designs , using HTS winding both on rotor and stator, show power densities up to 40kW/kg at rotational speeds of about 10,000 rpm [17]. Several institutions have already realized partially superconducting systems, thereunder General Electric’s Homopolar Inductor Alternator with a power density of 8kW/kg [18]. Partially superconducting machines use superconducting windings on the rotor where DC currents induce a DC magnetic field, interacting with copper stator windings which are excitated with alternating current. Current superconducting material like BSCCO and YBCO shows AC losses which make their use as stator windings impractical until now [16]. A lot of effort on research for low AC loss HTS material is done by several research centres and companies. According to the American Institute of Physics, MgB2 with a critical temperature of 39K and best performance under 30K, shows high potential to reduce AC losses when arranged as fine, twisted filaments [16]. Liquid hydrogen is on a temperature level well below the critical temperature of MgB2 thus improving its current carrying capacity [19]. Based on NASA’s technology roadmap, power densities of HTS machines - including generators and motors - are predicted to be as high as 33kW/kg [20]. Further calculations for the Polaris concept will use a more conservative value of 20 kW/kg.

4.4 Fuel System

In comparison to kerosene tanks liquid hydrogen tanks must be able to fulfill more requirements. To the general task of keeping the fuel in its desired place, LH2 tanks have to keep the hydrogen in a liquid state. This means the inner temperature has to be kept at 21.7 K at a pressure of 1.4479 bar [43]. The tank configuration has next to storage reasons also operational and integrational causes. The final decision can be seen in figure 4.2. As you can see above we decided to use six tanks. Two of them are always arranged alongside and in a parallel way. If they are fully loaded with 2200 kg, the front tanks carry each 600 kg amount of LH2. The residual smaller ones carry 250 kg per tank. The segmentation has on the one side operational reasons and on the other hand weight and balance causes. Due to the relatively high impact of the tank weight on the OME, an extra short-range version is planned. Therefore, unnecessary tanks should be removable, in order to convert the aircraft. The second segmentation has its reason in the position of the wing. Its structure divides the aft tanks into two parts. This results in four smaller tanks. The aft ones close to the engine functions as a feeder tanks whereas the other ones can be removed if this is desired. The main driver for tank configurations are explained in more detailed beneath.

Volume

The basis to an effective tank configuration is to reach necessary storable volume, which is desired for the intended missions. With the known density of liquid hydrogen, this is a fixed value to deal with [44].

Shape

The second driver is the tank’s shape. Due to the very low density of LH2 the integration was the main problem when designing a hydrogen aircraft in the past. The ideal shape to store liquid hydrogen is a sphere because it reduces the surface area, which is the main reason for a high rate of vaporizing hydrogen. Of course, it is not possible to fit all fuel in one sphere. The logical conclusion, when looking at the fuselage is a cylindrical shaped tank. The pressure distribution is not as good, but with two hemispheres closing the cylinder, it is still feasible [44]. With respect to the available space in the fuselage the outer diameter of the cylinder is fixed and with it the resulting length of the tanks, too. Additional improvements can be gained by the use of a dished bottoms instead of the hemispheres. It small disadvantages in terms of surface area but a reduction of the tank’s length makes the choice reasonable [45]. Both the cylindrical shape and die dashed bottom help to reach the goal to place the tank in the lower fuselage and are quite easy to manufacture. This has big advantages concerning the aerodynamics compared to other projects which decide to attach them outside the fuselage [44]. There are two basic possibilities to integrate the tank in the fuselage. The chosen one is the non-integral way. Studies say integral tanks only have small weight advantage, which gets smaller if you increase the design life up to the service life of the aircraft [43]. Safety thoughts made the final decision. Damages at the fuselage structure don’t follow in a loss of all the fuel if you use non-integral tanks. On top of that they are removable which makes maintenance inspections much more easier and the short-range version possible.

Insulation

The wall structure of an LH2 tank is closely linked with to the selection of the insulation material. The chosen material is polyurethane, a from CO2 frothed up foam. It is easy to handle, cheap and has a low density. Other vacuum-based insulations turn out to be too dangerous in the case of a vacuum loss [44]. The structure can be seen in figure 4.6. Due to heat transfer effects the stored LH2 changes phase to GH2 which can diffuse through the tank wall. That makes the insulation neces- sary. The amount of diffused hydrogen by time mostly depends on the tank’s surface area and on the insulation layer thickness. This amount can be estimated by equations based on [45]. Although it is recommended to leave the hydro- gen in the aircraft even on ground over night, it might be possible to defuel when the aircraft is out of service. This might be the case if there is a major maintenance event coming up or the tanks need an inspection them self. Tanks need to be checked every 4000 flight hours. To inspect them from inside the LH2 has to be removed, purged and filled with breathable air. After defueling and purging there is still GH2 left in the tanks. The warm up procedure can be started and after reaching 77.6 K the fuel storage can be filled with dry nitrogen gas. This procedure removes nearly all left hydrogen. After flushing them with air to remove the nitrogen, the tank can be entered [43]. Refueling procedure is similar but in reverse order. By nitrogen air and CO2 are flushed out. Purging the tank from nitrogen is done by GH2. During that the chill-down process of the tank starts by the use of cold GH2 . Fueling a warm tank with LH2 must be conducted slowly at first to avoid over-pressurizing. The flow rate can be increased with decreasing a tank temperature. This whole process must be done over night, to prevent absence form service [43].

Fuel System Safety

In contrast to aircrafts with standard configurations, storing the fuel in the tanks, the hydrogen tanks are located in the belly of the fuselage. This means they are directly placed underneath the cabin. Therefore special considerations have to be made. In case of a damage of the tanks it must be proven that leakage does not interfere with passenger’s safety.

"In most cases a comparison of fuels will show hydrogen to be the safest and least devastating"
- Bhupendra Khandelwal et al in Hydrogen powered aircraft : The future of air transport, January 2013

Releases of LH2 out of tanks at a rate of 60 L/min were investigated under conditions of ignited and unignited leakage [47]. The unignited test showed that a pool of liquid and large solid deposits are produced. They kept stable in their phase and disappear after several minutes. Tests with ignition of the vapor above the solid deposit pointed out that a flame emerges but no explosion occurs [47]. In comparison to that kerosene fill out as much space a possible. LH2 is localized to the leak and vaporising in a controlled way [44]. In the ignited case turned out to be difficult. The clouds of H2 occurred after the leak of LH2 is difficult to ignite. The reason may be that the gas cloud is over-rich in hydrogen. In case of an successful ignition the hydrogen burned out in the form of a gentle jet flame from the release point about 1 meter high. It was discovered that hydrogen flames usually radiate less heat than hydrocarbon gases flames. While kerosene burned out in an uncontrolled way endangering the passengers with high risk for loss of lifes, LH2 is shone to flame out in a very controlled manner. No fire carpet will be formed [44]. Furthermore, flammability tests prove the liquid hydrogen to burn around 14 times faster than kerosene for the same fuel volume. Burn- ing 121L of propellant takes 27s or 7min respectively. The reduced time span will prevent the fuselage to collapse due to high heat levels [43].

VV wrote:

Baldr wrote:

VV wrote:

I think it is a good thing, especially if the fund is used to define products in a pragmatic way and is not driven by an ideology toward targets that are not achievable.

"pragmatic": ???

"ideology": ???

"not achievable": IMJ, The EIS of a LH2-powered airliner is achievable by 2035.

If you say so, but I do not believe it would happen in 2035.

They should use the money wisely.

A380MSN004 wrote:

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop?
Since when do governments know which products are good for companies?
I really hope this plan hasn't been finalized yet and that the German and Spanish governments will kill it.

Reminds the Concorde saga

kjeld0d wrote:

A380MSN004 wrote:

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop?
Since when do governments know which products are good for companies?
I really hope this plan hasn't been finalized yet and that the German and Spanish governments will kill it.

Reminds the Concorde saga

Utility prices are already 4-5x what they are in North America. How much more can they burden the ordinary taxpayer with pie-in-the-sky nonsense ideas like this?

kjeld0d wrote:

A380MSN004 wrote:

kyu wrote:

So is the French government attempting to dictate Airbus which planes to develop?
Since when do governments know which products are good for companies?
I really hope this plan hasn't been finalized yet and that the German and Spanish governments will kill it.

Reminds the Concorde saga

Amazing how much of a disconnect there is between the top-heavy EU governments and the needs of the "man on the street". Utility prices are already 4-5x what they are in North America. How much more can they burden the ordinary taxpayer with pie-in-the-sky nonsense ideas like this?

Baldr wrote:

...
Therefore, the question you should ask yourself is if Boeing would be using their money wisely if they would decide to launch an all new NSA and/or an A321neo competitor, with the risk of being faced with an Airbus zero CO2 emission single-aisle aircraft entering into service only a few years after their conventionally powered single-aisle Max replacement aircraft?

VV wrote:

Baldr wrote:

...
Therefore, the question you should ask yourself is if Boeing would be using their money wisely if they would decide to launch an all new NSA and/or an A321neo competitor, with the risk of being faced with an Airbus zero CO2 emission single-aisle aircraft entering into service only a few years after their conventionally powered single-aisle Max replacement aircraft?

Why would they even consider doing that now?
It would be a very unwise way to spend money.

Noshow wrote:

The MAX has the same engine generation as the neo. Given that the problems are hopefully solved now it should live about as long as the competitor. Hydrogen aircraft are something for 2050. There is room for another generation of conventional aircraft in between. New, more efficient engines needed for the business case will be available in the second half of the 2020s it seems. That will be the moment Boeing cannot let pass.

Baldr wrote:

...
Now, maybe it would suit Boeing better if liquid hydrogen powered aircraft only would arrive in the 2050s, but what will they do if Airbus develops a ZERO CO2 emission aircraft arriving in 2035?
...