The Exception to the Green Propulsion Rule

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By Bjorn Fehrm

November 30, 2023, © Leeham News: The interest in Green alternative propulsion for airliners started in earnest at Farnborough Air Show 2014, where Airbus flew the E-Fan battery-electric aircraft. What followed was a dense stream of alternative propulsion airliner projects.

They all have in common that nothing much has come out of them. We have a Pipistrel two-seat trainer that can fly for 50 minutes on batteries, but not much else. More elaborate projects have wide slips in their plans, and nine years later, we lack real prototypes for all projects.

We have functional models flying for nine-seat hybrids and 19/30-seat hydrogen fuel cell aircraft that swap one engine for a Green alternative. Of the latter, there is one project that stands out from the rest. It has shown real progress over the last years and has realistic plans for a 55-seat hydrogen airliner that can be operational in three to four years.

We will analyze why the Universal Hydrogen ATR fuel cell project is the exception to the “Green Propulsion Rule,” that nothing comes out of all plans, and why it could be the first Green Propulsion airliner, ending a 10-year draught.

Figure 1. The Universal Hydrogen Dash 8-300 functional demonstrator. Source: Universal Hydrogen.

Summary:
  • A Green Propulsion project means the airliner does not use hydrocarbon-burning (Kerosene or SAF) gas turbines.
  • The project that breaks the rule that nothing seems to reach practical use this side of 2030 is the Universal Hydrogen ATR project.

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What’s the Green aviation news at Paris 2023?

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By Bjorn Fehrm

June 22, 2023, © Leeham News: Every announcement from aircraft deals, OEM updates, or supply chain news now has the words Sustainable/Sustainability injected in every second sentence. It doesn’t matter what the subject is; if it’s about a gas-guzzling way of transporting people at supersonic or even hypersonic speeds or at the other end in an eVTOL which is only as fast as your car on a US highway.

What is the real news about making our air transport system less polluting behind this misuse of the buzzwords? You have to search behind the headlines and the announcements that you know will not turn the dial. Let’s tour the Paris Air Show 2023 and look at the real developments in Sustainability.

Figure 1. First flight of Universal Hydrogen’s DH8-300 with a hydrogen propulsion system on the starboard side. Source: Universal Hydrogen.

Summary:
  • The waves of Green propulsion solutions with inflated claims have calmed down.
  • It’s replaced with operationally usable solutions that deliver tangible emission gains.

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Bjorn’s Corner: New aircraft technologies. Part 10. Engine choice

By Bjorn Fehrm.

April 28, 2023, ©. Leeham News: This is a summary of the article New aircraft technologies. Part 10P. Engine choice. The article discusses the engine architecture choices that must be made when developing the next-generation airliners.

Figure 1. The Pratt & Whitney high bypass geared turbofan technologies. Source: Pratt & Whitney.

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Bjorn’s Corner: New aircraft technologies. Part 10P. The engine choice

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By Bjorn Fehrm

April 28, 2023, ©. Leeham News: This is a complementary article to Part 10. The engine choice. It discusses in detail the next-generation engines for the Heart of the Market airliners that today are called the single-aisle segment. What will be the alternatives and final engine choice? Will hydrogen-fueled engines play a role?

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The Small Airliner problem, Part 2

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By Bjorn Fehrm

April 27, 2023, © Leeham News: We started a series about the viability of the business plans for small airliners (nine to 50 seats) last week in the light of a continuing decline of regional airlines in the US and Europe.

To understand whether fundamentals are stacked against small airliners, we look at operational cost factors and how these scale with aircraft size. Then we add the revenue and yield and discuss the conditions for viable business plans for different size aircraft.

This week we use the Leeham airliner performance and cost model to compare the airframe energy and fuel consumptions for airliners spanning nine to 200 seats.

Figure 1. Eviation Alice is a battery-based nine-seat electric aircraft. Source: Eviation.

Summary:
  • On an airframe energy level, a smaller airliner consumes more energy per transported passenger than a larger one.
  • If we change the metric to propulsion energy consumption, the trend is augmented as small propulsion solutions are less efficient than larger ones.

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Bjorn’s Corner: Sustainable Air Transport. Part 58. Summary Part 2.

By Bjorn Fehrm

February 17, 2023, ©. Leeham News: Last week, we summarized that SAF is the short-term solution for GreenHouse Gas (GHG) reduction for Air Transport, and hydrogen is the longer-term solution for up to medium-haul flights.

What about battery and hybrid aircraft? It’s the go-to solution for ground transport (except for long-haul trucks, which are going hydrogen, Figure 1)?

Figure 1. Mercedes hydrogen truck from the world’s largest truck maker. Source: Daimler trucks.

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Bjorn’s Corner: Sustainable Air Transport. Part 57. Summary

By Bjorn Fehrm

February 10, 2023, ©. Leeham News: We started the present series around Sustainable Air Transport on the 7th of January 2022, more than a year ago. During this time, we have covered a lot of subjects regarding the emissions from Air Transport.

It’s time to wrap up the series and summarize what we covered and learned.

Figure 1. Our energy consumption and where it’s coming from. Source: Our World in Data.

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Bjorn’s Corner: Sustainable Air Transport. Part 55. Sustainable Aviation Fuel feedstocks

By Bjorn Fehrm

January 27, 2023, ©. Leeham News: Last week, we learned the main pathways to Sustainable Aviation Fuel and their production volumes for the next years.

Now we look at the feedstocks, what output we get from these, and how to safeguard the pathway is ethical and sustainable. Finally, we look at the cost of SAF until 2050.

Figure 1. The main pathways to SAF. Source: Clean Skies for Tomorrow report. Click to enlarge.

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2023 outlook for Sustainable Aviation

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By Bjorn Fehrm

Jan. 16, 2023, © Leeham News: In the years from 2015, Sustainable Aviation awareness has grown from “something interesting, but will it be needed?” to “how do we fix the environmental issues we have fast enough.” Scientists saw what happened 20 years ago, but the general public didn’t react until it affected everyday life.

The development of more Sustainable Aviation solutions has taken a similar route. Until 2015 the changes to morph aviation into a more sustainable path were a scientific discussion. At Le Bourget Air Show 2015, Airbus presented the E-Fan (Figure 1) that would cross the English Channel the following month. It started an intense debate about sustainable propulsion concepts for aircraft.

Eight years later, where are we today, and what will happen in 2023?

Figure 1. Airbus E-Fan at the 2015 Le Bourget Air Show. Source: Wikipedia.

Summary:
  • The year will witness the “separation of the wheat from the chaff.” Viable concepts will prove themselves, and thin concepts, technically or funding-wise, will fail.
  • We have a number of first flights from interesting projects. Several are in the “wheat” category.

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Bjorn’s Corner: Sustainable Air Transport. Part 53. Sustainable Aviation Fuel

By Bjorn Fehrm.

January 13, 2023, ©. Leeham News: Last week, we could see in an example how effective Sustainable Aviation Fuel, SAF, blended into our regular Jet fuel, would be in reducing CO2 emissions until 2050.

It’s the only technology that can substantially influence our emissions over the next 30 years, as alternate technologies like hydrogen-fueled airliners need to ramp to thousands of aircraft before it affects emissions.

To understand SAF and how it can be produced and blended into Jet fuel, we first need to understand what Jet fuel is.

 

Figure 1. An Iberia A340 filled up with Jet-A1. Source: Wikipedia.

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