That is out of our scope as a business but it is something we have found we have to address head on with our customers and airport partners. They want to understand the whole logistics and associated safety from green H2 production to aircraft tank. We don't have it all figured out yet but we are working with some great partners on the problem. We have created a Hydrogen Flight Alliance here in Brisbane https://newsroom.bne.com.au/hydrogen-flight-alliance-launche... that includes, BOC (a Linde Company) and H2EC who are tackling the logistics and re-fueling of liquid hydrogen. Note that we are using liquid H2, which is more expensive than gas, but comes with a variety of benefits, one of which is that it is stored at low pressure. We could opt to store it just over ambient pressure but we will most likely go with storing it < 10 bar - much less than the 350 - 900 bar, that gaseous H2 is typically stored at.
They are aiming to be the propulsion system supplier for future aircraft but crucially the are also targeting developing systems for a family of aircraft starting small and are working towards aircraft upwards of 200 seats. Our premise is to not look past 50 seats. If we were to design a 200 seat aircraft its CASM would not be much cheaper than the 50 seat if we aim to do a single aircraft type from the start, then we can aim for much higher volumes than aircraft programs traditionally achieve and ultimately bring our unit costs right down and undercut anyone else working on a family of aircraft.
We were so close to buying an old Nomad for our tech demo! But we thought if we took it to an airshow, it would only get a small sub-set of attendees excited, compared to a Bonanza, which people seem to love.
We would really love to do it all in Australia and think Australia is a great place to do the initial development work, flight testing our tech demo and retrofitting the first set of our B1900D-HE product. But we would, reluctantly, agree with you that the SA-1 design, testing and manufacturing would be at best global but most likely heavily centered in the USA. Its our plan to grow the team in the states, starting soon, and slowly shift the center of gravity as the projects move through maturity.
The air needed for the chemical reaction is pretty small, but we will also be drawing in some air for cooling and that will be around the same order of air that is used by a turbine engine. We will not have an APU per se, but we will have a small amount of battery to start the propulsion system and this can provide power to the aircraft systems for some time. We can also start up the fuel cells if need be to supply extra power, without turning the electric motor and propellers.
The lowest hanging fruit is the current 50-80 seat turboprop market. Next would be the regional jet market and lastly we want to capture a sizeable portion of the single -aisle market. The reason we want to compete with/capture traffic served by 737s and the like is that the market is enormous - we are estimating $1.7T over the next 20 years if we were to replace single-aisle with our 50-seat, SA-1. The reason that we believe we could compete is because we believe that we could bring the CASM of the 50-seater down to be on par with a 737, and combined with the emission reduction we think that this is compelling offer for airlines.
Our aim is not to have to compete with 737s at airports that are slot constrained but to make use of the 100s of underutilised airports across America. By bringing down the CASM of a 50 seater, we believe that this would increase the passenger traffic too and from those airport and make the currently thin routes more profitable.
My pleasure! Yeah working with the H3X team has been great. We are going to have them out at the airport before the end of the year, letting them run some tests on our set up. Will be fun.
Yeah even with today's batteries there is a business case for battery electric flight. Trainers, short hops across water and intracity + eVTOLs of course all make sense to tackle with battery. This is because the efficiency is good, the cost can be potentially very low and the infrastructure is manageable. But as a solution to decarbonising a large proportion of aviation - it doesn't work. We want to find a solution to serve the enormous number of passengers that fly up to 3000 km. If we can tackle that, we can cut more than 50% of aviation emissions.
One thing we have learned on this journey is how much low noise is to our customers and the wider community - we have yet to really put this under test and try and get a cost number against it i.e. how much more would you pay for a quieter engine?
What we do have is an opportunity to be much quieter, but there is always a penalty to pay in terms of size. For example, unlike a battery aircraft, we still have to provide the fuel cells with air and we can do that with large quiet ducts or small noisy ones - but larger ones take up valuable real estate and ultimately add weight to the system.
What I can say is we will design it to be quieter than current jet engines, but where we draw the line is tbd.
I think I would be hard pressed to say maintenance free but definitely significantly lower maintenance costs. Turbine blades are intrinsically expensive, made of titanium and operate at high temperatures under high loads. Electric motors have much simpler operation and when made at scale, can really benefit from a replace after 20,000 hours model, instead of a overhaul every 1800 hours, with 200hrs inspection intervals, which we see in some turboprop engines. Fuel cells and batteries are much the same, replace after a certain life, and with built in tolerance to failures. Unfortunately, with fuel cells, as opposed to batteries, we still have some balance of plant that will need maintained, compressors for example, however unlike a turbine engine, they don't operate at high temperatures and are a smaller part of the system, so we can design for much longer lifetimes that you can get away with in a turboprop. All this leads us to estimating 65% saving on engine maintenance. Battery electric companies are going after more like a 90% saving.
We are not really targeting the private or business jet market (though if someone wanted one for this purpose we wouldn't turn them away!). There is another impressive YC company that is that you should check out, Beyond Aero https://bookface.ycombinator.com/company/26134
We are really targeting a low cost commercial market - moving people and cargo. The smaller size is driven in part by the technology - with 50 seats being a good size to capture a large proportion of flying traffic - and partly that it will be faster and cheaper to certify and get a smaller aircraft into the market.
I think that is a fair statement. You also have to factor in the capital costs, the aircraft purchase price per seat typically increases with aircraft size so it comes down to the balance there, between that cost increasing and other costs decreasing. The scales can tip either way depending on the circumstances. For a 737, we have that capital costs contribute about 40% of the CASM, whereas Crew is 4% and Maintenance is 16%.
In conventional aircraft, the efficiency of larger engines really vs smaller ones really push towards larger aircraft.
Thank you, I can confirm it is the coolest job I have had so far, and I have done quite a few cool things. I can also tell you, as someone who studied physics, I have only really spent about 10% of my time in the last year doing any physics! So much other stuff to get through...
Yeah the compressor load goes up with power - we have a 27 kW compressor for our 120kW PEM fuel cell here in the lab (this isn't what is going on the aircraft). This is one of the issues we are tackling with our unique system architecture for the aircraft.
We would love to do the analysis you are describing in detail. I'm thinking getting people movement data from google maps or something, using that to figure out where people are traveling to. Then use that to determine what traffic needs to go through the major airports and who would be better off going to local airports and really map the traffic in detail. Then overlay our cost data to see what is the real optimum. If anyone can help with that we would love to chat!
We think for a high proportion of routes 50 seats for hydrogen electric propulsion. We heard from a major airline that their network planners always want a smaller plane, for flexibility and a high load factor and the fleet planners always want a large plane for lower CASM and fewer aircraft, that tension has basically landed on the single-aisle size (180-200 seats) for most routes with conventional propulsion. But this changes with the technology as different cost drivers have different rates of change with seat count.
A good indicative document is https://ntrs.nasa.gov/api/citations/20160007749/downloads/20..., this is asking "if you were to serve the market with only one plane, how many seats should it have?"
We can't share too much detail but it has higher operating temperatures (180C) than the standard PEM fuel cells that are typically used in automotive. This is key to a good aircraft solution.
Not this time around! We have selected H3X as our supplier for the motor for our tech demo and have signed an LOI for them to supply motors for our B1900D-HE retrofit aircraft. I would say that magniX has a more mature product and is further along the path to certification and its flown many of the recent and impressive electric aircraft first flights, including our competitor Universal Hydrogen. I'll always have a soft spot for the magni650, but at the end of the day, weight is critical on an aircraft and H3X are showing us a lighter product. We have a good relationship with H3X and have confidence that they will be able to meet the cert criteria in our timelines.
Thanks - I hear you, safety around hydrogen is always a big concern. We do address it head on often but it will always come up in any conversation about it. The "why not batteries? question is audience dependent - some people have given up on batteries and others, they see that it works for EVs so expect it to work for aircraft too. Will keep your feedback in mind, especially for sales!
Did someone say autonomous flight?? only kidding, we are not pursuing autonomous flight in the near future. It is something we hear a lot about too, especially after COVID. I am not sure what the answer is here but we do see it as a temporary thing and expect that the market will sort itself out. Whilst fully autonomous flight may not be our focus, we hope to do some things that can reduce the workload of the pilot and perhaps help reduce the training burden of crew making the pathway to that career more attractive. We are actually co-located with Australia's biggest Aviation training provider so we receive a lot of feedback in this regard.
It is definitely a design constraint that we have to consider but at the same time the relatively small change in weight during the flight is also good for our balance, given we won't be putting the fuel in the wings. All in all, the sources of weight are pretty different between the conventional jet-kerosene versus our hydrogen electric propulsion, which is what is driving us to a clean sheet design to take maximum advantage of HEP. We are doing a 15-seat retrofit of a Beech 1900D as our first product, and while it is a great MVP, the landing weight constraint, amongst others, make it a little less capable, with 800km range, than the conventional version.
We watch H2fly in very carefully! They are a really impressive company and their recent flight with liquid hydrogen is inspirational, and really motivates us. I believe we have some different fuel cell technology but the main difference is that we plan to develop the SA-1 as a clean sheet air frame that will be optimised for this new fuel type and propulsion system. H2fly are aiming to sell propulsion systems, perhaps we could be partners one day if their system performs better than ours.
We will be basing our requirements broadly on the current Dash8-300, so we are targeting around 4000ft for the SA-1, but we still have a lot of work before that is validated. It is desirable for us to go with smaller planes as it is faster to market, much lower program costs but we just don't feel that it will have the same impact - both as a business and on carbon emissions. As you go smaller, some costs increase per passenger, like crew and engine maintenance start to dominate at that <12 seat size, and whilst the Pilatus PC-12 is a hugely popular plane, its just not something that could compete with the major single-aisle market. Accessing this market is what would give us the edge and really allow us to build an unusually high number of planes.
Yeah there will be some slot constrained routes that will certainly need to stick to the larger aircraft sizes, but many that can benefit from the flexibility of a smaller aircraft size if the operating cost was low enough. There are second city airport and regional routes that would benefit from the smaller plane size, as well as the market that is currently served by these types of planes - Asia pacific is one example of a growing turboprop market.
There is definitely advantages of both. Direct combustion gets you a much greater specific power of propulsion, and the technology for turbine engines is so optimised that it sounds like a really attractive option. We expect we can get higher efficiency with fuel cells and the engine maintenance costs will be lower as fuel cells and electric motors operate at low temperature. Both of these cost drivers lead to a lower CASM.
Exactly! We will be flying "Bonnie" our Beechcraft Bonanza on an experimental ticket next year. We will then do the same for each of other programs. This helps us get the hours and data to support our certification process.
Yeah certification is one of our biggest risks. Luckily for us there are already a few other companies that are breaking the ground here and the certification path is becoming less opaque. There is a lot of scrutiny for new propulsion types but the certification process is largely the same - its more that we don't have the luxury of experience and being able to point to "similarity" to show compliance. We are budgeting ~$50M for our 15-seat retrofit product development and cert and a bit more than 10X that for the 50 seat product.