Sustainable Aero Lab disqualifies “Greenwash” investments

By Bjorn Fehrm

August 25, 2021, ©. Leeham News: Times change and the use of words with it. Today, the hundreds of UAM Air Taxi projects talk about how “environmentally friendly” this mode of transportation is, and Boom’s Overture is “the most Sustainable supersonic airliner.” The aerospace media recently focused on how we now have “Space Travel for everyone (in possession of the necessary pocket change).”

The head of Sustainable Aero Lab, Stephan Uhrenbacher, disqualifies these investments in a study on where to invest in fixing air transport’s pressing problems: “The startups receiving the most attention in aerospace recently have been doing space travel and urban air taxis. While these products make for exiting flying objects and satisfy human desire, neither air taxis nor putting more people in space address the problem facing commercial aviation: Flying needs to become carbon-free. And this needs to happen much faster than most people in the industry believe. It opens room for startups to provide components for future aircraft or even entire planes, but also new modes of operation.”

Figure 1. The promising Sustainable Aviation startups. Source: Sustainable Aero Lab.

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Airbus delivers strong 1H2021 and launches A350 Freighter

By Bjorn Fehrm

July 29, 2020, © Leeham News: Airbus presented its results for the first half of 2021 today. The company reported a profit of €2.7bn on a turnover of €24.6bn, a very strong result from the -€0.9bn of last year.  Yesterday, the Airbus board gave the go-ahead for the A350 freighter with planned entry into service 2025.

The strong result came from deliveries of 297 commercial aircraft, 100 more than the 196 of 1H2020. Net orders were 38 aircraft (1H2020 196). Guidance for 2021 was increased to 600 airliner deliveries with operating profit at €4bn and Free Cash Flow of €2bn.

Artist impression of the A350 Freighter. Credit:

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Bjorn’s Corner: The challenges of airliner development. Part 11. The Program Plan.

By Bjorn Fehrm, Henry Tam, and Andrew Telesca.

July 9, 2021, ©. Leeham News: Now that we have done the basic market research we should scope the program. To do this we need to understand what aircraft we will develop and to what certification rules.

Our market research tells us to develop a 19 seat aircraft that can operate as a passenger and/or cargo aircraft outside the US and as cargo aircraft in the US. This enables us to certify it to FAA Part 23 and the equivalent rules of other National Aviation Authorities where we want to sell the aircraft.

Figure 1. The new Cessna SkyCourier Cargo/19 seat utility airliner. Source: Cessna.

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The true cost of Electric Aircraft. Part 2.

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By Bjorn Fehrm


July 8, 2021, © Leeham News: Last week, we looked at the cost of running an electric 19 seat airliner based on energy stored in batteries. We found the energy costs were lower than for the equivalent turboprop aircraft, but when we add the maintenance costs for the batteries, the operating costs were higher than today’s 19 seat commuter.

This was under the assumption that the battery aircraft had the same energy consumption as today’s aircraft. We now run this check. The result is eye-opening.

Figure 1. Heart Aerospace ES-19 battery-based airliner. Source: Heart Aerospace.

  • Battery based aircraft weigh significantly more than jet fuel based ones. It increases their energy consumption.
  • Last week’s findings were conditioned on the same energy consumption. This week’s analysis proofs this is not a valid assumption.

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Bjorn’s Corner: The challenges of hydrogen. Part 33. Wrap-up: The Eco-system

By Bjorn Fehrm

April 16, 2021, ©. Leeham News: Last week, we wrapped up the operational part of sustainable air transport using hydrogen as an energy source.

Now we look at where we are with the all-important Eco-system. It has many moving parts and risks a chicken and egg stalemate.Figure 1. The prospective conversion of the European gas pipeline network to hydrogen. Source: EU.

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Bjorn’s Corner: The challenges of hydrogen. Part 32. Wrap-up: Going forward

By Bjorn Fehrm

April 9, 2021, ©. Leeham News: Last week we made a summary of the history of initiatives for sustainable aviation, now we look at the likely developments over the next 10 years.

What is the likely development for different classes of airliners and what technologies will be popular?

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Bjorn’s Corner: The challenges of hydrogen. Part 31. Wrap-up: Where we stand

By Bjorn Fehrm

April 2, 2021, ©. Leeham News: It’s time to wrap up our series on the hydrogen airliner alternative for Sustainable Commercial Aviation.

We review the status for sustainable aviation as of today, then look at the future next week.

Figure 1. The first certified electric aircraft, the Pipistrel Velis Electro. Source: Pipistrel.

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Bjorn’s Corner: The challenges of hydrogen. Part 30. Integrated nacelles.

By Bjorn Fehrm

March 26, 2021, ©. Leeham News: This week, we look at combining the propulsion and hydrogen tank in an integrated nacelle as Airbus proposes in Figure 1.

Airbus calls it its “pod” solution. What are the advantages, and what challenges does it present?

Figure 1. Airbus concept for a turboprop with integrated nacelles. Source: Airbus.

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Bjorn’s Corner: The challenges of hydrogen. Part 29. Gas turbine heat management.

By Bjorn Fehrm

March 19, 2021, ©. Leeham News: This week we look deeper into the gains we can have for a hydrogen gas turbine-propelled airliner.

The ideas stem from the work of Chalmers Professor T. Grönstedt’s team in different EU research projects.

Figure 1. Gas Turbine heat management as presented in EU ENABLEH2 project. Source: ENABLEH2.

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Bjorn’s Corner: The challenges of hydrogen. Part 28. Airbus priorities

March 12, 2021, ©. Leeham News: I had the chance to talk about Sustainable Air Transport with Airbus VP Zero Emission Aircraft, Glenn Llewellyn, in the week.

The discussion centered around Airbus’ overall direction and the targets with their ZEROe project.

Figure 1. Airbus ZEROe airliner concepts. Source: Airbus.

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