The ZEROe Demonstrator Has Arrived
The title of this post, is the same as that of this press release from Airbus.
This is the introductory paragraph.
2022 marks a new and exciting phase for ZEROe – Airbus’ ambition to develop the world’s first zero-emission commercial aircraft by 2035. The multi-year demonstrator programme has officially been launched with the objective to test a variety of hydrogen technologies both on the ground and in the air.
The ZEROe demonstrator will be the first Airbus A 380 aircraft and it is shown in this Airbus visualisation.
Note.
- The four hydrogen tanks in the fuselage.
- The fifth engine mounted in a pod on the fuselage.
- There’s certainly lots of space inside the fuselage for more hydrogen tanks and test and monitoring equipment.
I have a few thoughts.
This Aircraft Will Be A Superb Demonstrator
The press release says this about the use of an A 380 as a demonstrator.
The A380 is the world’s largest and most spacious passenger jet ever built – a size that makes it ideally suited to the role of test platform.
Today, the A380 MSN1 test aircraft is earmarked for a new role: to take the lead on testing the technologies that will be vital to bringing the world’s first zero-emission aircraft to market by 2035.
“The A380 MSN1 is an excellent flight laboratory platform for new hydrogen technologies,” says Mathias Andriamisaina, Airbus ZEROe Demonstrator Leader. “It’s a safe and reliable platform that is highly versatile to test a wide range of zero-emission technologies. In addition, the platform can comfortably accommodate the large flight test instrumentation that will be needed to analyse the performance of the hydrogen in the hydrogen-propulsion system.”
Initially, I suspect the aircraft will fly as a four-engined turbofan aircraft running on standard or sustainable aviation fuel.
The performance of the hydrogen engine will be tested in all phases of operation and at different altitudes.
What Size Is The Fifth Engine?
This layout is clever.
If Airbus want to test a smaller hydrogen engine for say an Airbus A 320-sized hydrogen aircraft like the ZEROe Turbofan shown in this Airbus visualisation, they fit it to the fifth pylon.
Note.
- The fifth pylon on the ZEROe Demonstrator could be the proposed pylon for the ZEROe Turbofan.
- The ZEROe Demonstrator could probably carry a lot of hydrogen to test out the hydrogen engine over a long duration.
- The hydrogen engine could be tested out over the full flight envelop of an Airbus A 380.
I would suspect that the tests on the hydrogen engine would be some of the most comprehensive ever carried out on a new engine.
If Airbus want to test a larger hydrogen engine for say an Airbus A 350-sized hydrogen aircraft, they would probably replace one of the four main engines with the hydrogen engine.
It looks like Airbus will be able to test hydrogen engines for all sizes of plane in their current range.
What Will Happen To Current A 380s?
Consider.
- The production of the A 380 has been stopped.
- There are 251 aircraft in service.
- They appear to be a reliable and safe aircraft.
- The aircraft can run on sustainable aviation fuel.
- The oldest aircraft are only thirteen years old.
- They are still reasonably modern aircraft, that if they needed to be updated to the latest standards could probably be easily done so.
- The aircraft have a lot of volume, which can hold over 500 passengers in a typical configuration.
- The flying characteristics and structure of the aircraft is well known.
I suspect there are a lot of aircraft leasing companies, who feel these aircraft are too good to scrap, just because they are not zero-carbon.
Could Hydrogen Be Stored In The Wing Of An A 380?
Hydrogen storage will get more capable in the next few years and we will see hydrogen stored in strange places in vehicles and aircraft using the gas as a fuel.
The A 380 may well have an advantage in that its wing is relatively thick compared to that of other airliners.
- The A 380 has a wing aspect ratio of 7.53.
- The Boeing 787 has a wing aspect ratio of 11.
- Gliders have wing aspect ratios as upwards of 30.
High aspect ratios are generally more economical on fuel.
But this relatively thick wing, may make it possible to store hydrogen in the wing of an A 380.
Could There Be A Hydrogen-Powered A 380?
I suspect part of the Airbus ZEROe progam will be to investigate the possibility of converting existing A 380 aircraft into a capable hydrogen-powered aircraft.
In Could An A320 neo Be Rebuilt As A ZEROe Turbofan?, I looked at the possibility of turning an existing Airbus A 320 neo into a ZEROe Turbofan running on hydrogen.
This was my conclusion.
I very much feel that there will be a route to convert some or all of the A 320 neo aircraft to hydrogen power.
So what will a ZEROe A 380 look like if it follows the same design route as an A 320 neo to a ZEROe Turbofan?
- There would be a large hydrogen tank in the rear fuselage.
- As I explained earlier, there may be a possibility for some hydrogen to be stored in the wing.
- Both passenger decks would be shortened and perhaps be able to hold the 350-410 passengers of the Airbus A350-1000.
- The cockpit, front part of the fuselage, wings, tailplane and landing gear would be unchanged.
- The aircraft would fit existing jetways at any airport, that can handle an existing A 380.
I believe that converting an existing Airbus A380 to a hydrogen-powered aircraft is possible and the conversion falls within Barnes Wallis‘s rule of problem solving.
There is no greater thrill in life, that proving something is impossible and then showing how it can be done.
The quote comes from a BBC program, where he was interviewed by Chris Brasher, who was another for whom impossible was just a minor hurdle in the way of meeting objectives.
Could There Be A Hydrogen-Powered A 380 Freighter?
Consider.
- I think it is likely, that companies like Amazon will come under pressure over their carbon footprint, as they transport increasing numbers of packages around the world.
- In DHL Express Shapes Future For Sustainable Aviation With First Order Of All-Electric Cargo Planes From Eviation, I talk about how DHL Express have ordered twelve Eviation Alice aircraft to create a zero-carbon service. DHL must feel this would be good for their image. So would they like an intercontinental zero-carbon freighter?
- Some people worry about the air-miles on their food!
There could be a worthwhile niche market for a high capacity intercontinental zero-carbon freighter.
Because it has such a large internal volume, an Airbus A 380 might make an ideal aircraft to convert.
Conclusion
Airbus will learn a lot from the ZEROe Demonstrator.
They may even learn how to develop, a long-range hydrogen-powered zero-carbon A 380 variant that could carry four hundred passengers between Europe and Australia.
What Size Of Hydrogen Tank Will Be Needed On A ZEROe Turbofan?
I believe that Airbus’s proposed ZEROe Turbofan is designed for the same market segment as a A 320 neo.
- This aircraft has a fuel capacity of 26,730 litres of kerosene.
- This will have a mass of 21.38 tonnes.
- Each kilogram of kerosene can produce 46 Mega Joules of energy
- This means that full fuel tanks contain 983, 480 Mega Joules of energy.
- Each litre of liquid hydrogen can produce 10.273 Mega Joules of energy
This means that to carry the same amount of energy will need a 95,734.5 litres or 95.7 cubic metres of liquid hydrogen.
- This could be contained in a cylindrical tank with a diameter of 4 metres and a length of 7.6 metres.
- It would also weigh 6.93 tonnes.
As the range of the A 320 neo is given as 6,300 kilometres and that of the ZEROe Turbofan, as just 3,700 kilometres. the tank could probably be shorter.
Note that I used this Energy And Fuel Data Sheet from Birmingham University.
Conclusion
Carrying as much energy as an A 320 neo will be difficult.
- Range will be reduced.
- A new more efficient airframe will be necessary.
- As volume is probably more of a problem than weight, the fuselage might be lengthened by a few metres.
Designing the hydrogen system will be challenging, but I would be surprised if it were an insurmountable problem.
Could An A320 neo Be Rebuilt As A ZEROe Turbofan?
This post is a follow-up to ZEROe – Towards The World’s First Zero-Emission Commercial Aircraft.
I spent a lot of time yesterday, looking at YouTube videos of the following.
- Airbus A320 aircraft
- Airbus A 320 neo aircraft
- Airbus’s proposed ZEROe Turbofan aircraft
I also captured these profiles from the Airbus web site, of three members of the new Airbus A 320 neo family and the current Airbus A 320 ceo.
A 319 neo – Length – 33.84 metres – Max Passengers – 160
A 320 neo – Length 37.57 metres – Max Passengers – 194
A 321 neo – Length 44.51 metres – Max Passengers – 244
A 320 ceo – Length 37.57 – Max Passengers – 180
Note.
- The links on each variant lead to Airbus’s on-line specification.
- All three variants have a wing-span of 35.8 metres and a height of 11.76 metres.
- All variants have sharklets or blended winglets to improve awrodynamic efficiency.
- There are different door, cargo door and window layouts on all three variants.
- The cockpits, tail and wings look similar.
This capture from an Airbus video, shows the profile of the proposed ZEROe Turbofan.
Note, that the ZEROe Turbofan looks more streamlined than the A 320 neo family, with a redesigned nose and more swept-back tailfin and sharklets.
These are my thoughts on the current A 320 neo family and their relationship with the ZEROe Turbofan.
Focus On Commonality
For each variant on the Airbus web site, there is a section with this title. This is the first sentence for the A 320 neo.
Due to its 95 per cent airframe commonality with the A320ceo (current engine option) version, Airbus’ A320neo jetliner fits seamlessly into existing A320 Family fleets worldwide – which is a key factor for the company’s customers and operators.
Will Airbus follow this philosophy with the ZEROe Turbofan?
If it worked between the changeover between the existing A 320 fleets and the A 320 neo fleets, why change the policy?
The Cockpits
The cockpits of the A 320 neo and the A 320 ceo seem to have a similar profile, but the cockpit of the ZEROe Turbofan seems to have been reprofiled.
In ZEROe – Towards The World’s First Zero-Emission Commercial Aircraft, I showed these front on views of the cockpits of the ZEROe Turboprop and ZEROe Turbofan.
I questioned if the two cockpits were related.
- A single cockpit for both aircraft would surely ease manufacture, maintenance and pilot training.
- I’m no aerodynamicist, but it certainly looks that the new cockpit will reduce drag and fuel consumption.
Although the cockpit, appears to be being used in the ZEROe for the first time, I would expect it is already under development and might feature in any later version of the A 320 neo.
The Fuselages
The fuselage width for both the A 320 neo family and the A 320 ceo are all 3.95 metres, with a maximum cabin width of 3.70 metres.
I would expect that the ZEROe Turboprop and the ZEROe Turbofan will also use this width.
Airbus use a design called Cabin-Flex to get the most out of the interior space in the A 320 neo. This paragraph is from the Wikipedia section, that is entitled Cabin-Flex.
By permanently replacing the second door pair in front of the wing (R2/L2) with a new second pair of overwing exits, the capacity of the A321neo is increased from 220 seats to 240 seats and fuel efficiency per seat is increased by 6%, exceeding 20% together with the new engines and the sharklets. The modifications should weigh 100 kg more.[82] Initial A321neos have the A321ceo exit door configuration with four exit door pairs until the Airbus Cabin-Flex (ACF) layout can be selected.
After reading the whole section, it looks to me, that the A 320 neo fuselage is designed, to be all things to all airlines and doors and seats can be arranged to fit any requirements.
In the ZEROe Turbofan, there is a large liquid hydrogen tank behind the rear pressure bulkhead, which could be brought forward a bit to give more space and hydrogen capacity.
I suspect there will be a lot of commonality between the fuselage of the A 320 neo family and that of a ZEROe Turbofan.
I spent a lot of time, as a child building Airfix models of aircraft and it may be too much of a simplification to think of these carbon-composite airliners, as giant Airfix models.
But I wouldn’t be surprised that just like the previous generation of aluminium airliners, they can be remanufactured into something different, just like British Airways Tristars, ended up as tanker-aircraft for the RAF.
I wouldn’t be surprised to find, that later A 320 neo fuselages will be able to be remanufactured into fuselages for ZEROe Turbofans.
Comparing The Fuselages Of The A 320 ceo, A 320 neo And ZEROe Turbofan
These are the three fuselage profiles.
A 320 ceo
A 320 neo
ZEROe Turbofan
Aircraft balance on the wings, which if I remember what little I know about aircraft aerodynamics and design, apply their lift forces to the centre of gravity of the aircraft.
I know that the profile of the ZEROe is to a different scale, but three things are apparent.
- The windows at the rear don’t go as far back, as they do in the two existing designs. But then there is no need for windows around the hydrogen tank.
- The hydrogen tank could be as long as a quarter of the length of the fuselage.
- The front section of the aircraft appears longer.
The longer front section would balance the weight of the hydrogen tank.
The passengers would also help to balance the weight of the tank, by being placed further forward.
There must be the possibility of creating a larger capacity and longer range variant of the ZEROe design, by adding a larger hydrogen tank and further stretching the nose.
Airbus have been stretching these designs for years, so I suspect that they have plans for a large number of possible variants of the ZEROe Turbofan.
According to the Wikipedia entry for the A 320 neo family, there are already five civil versions of the A 320 neo; A 319 neo, A 320 neo, A 321 neo, A 321LR and A 321XLR, plus corporate and military versions.
Add in the Cabin-Flex interior and the various A320s and the ZEROe to come, must be one of the most flexible transport systems in history.
The Tailplanes
As they are of the same height and look similar, the tail sections of the A 320 neo and A 320 ceo families could be almost identical, but the tail section of the ZEROe Turbofan appears to be slightly more swept-back and perhaps more aerodynamic.
As the ZEROe Turbofan, also appears to have had a nose-job, I would suspect that Airbus have a redesigned fuselage in the works to squeeze more fuel-efficiency out of this family of already very frugal aircraft. Could this feature the more aerodynamic tailplane?
Could this advanced fuselage feature in a later version of the A 320 neo?
I also feel, that the functionality of the tailplane on the ZEROe Turbofan will need to be little different to that on the earlier planes.
- The plane is still powered by two turbofan engines on the wings.
- Rudder forces, with an engine failure on one side, will still be the same.
The big difference will be that the fuel is at the back of the fuselage rather than in the wings, which will affect the balance.
Will this effect the design of the tailplane? I don’t think it will in a large way, as Airbus seem to have lengthened the nose to compensate.
The Wings
All the wings with sharklets for the A 320 neo family and the A 320 ceo have the same wingspan of 35.8 metres, so I would expect they are all substantially similar.
But there is one big difference in that the wings of the conventionally-powered aircraft are full of fuel.
This would probably mean that much of the wing stresses in the ZEROe Turbofan would be like an A 320 neo flying with little fuel in the wing tanks. As some aircraft in the A320 neo family have fuselage tanks, Airbus can even test the wing forces and handling in a real aircraft.
But it does look that Airbus will have little trouble designing, building and certifying the wing of a ZEROe Turbofan.
There is a minor difference in that the sharklets for the ZEROe Turbofan are more extreme.
But then as I said earlier, is there a new more aerodynamic airframe for the A 320 neo in the works?
Conclusion
I very much feel that there will be a route to convert some or all of the A 320 neo aircraft to hydrogen power.