Leeham News and Analysis
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Leeham News and Analysis
- RTX Q1 2025 Earnings: GTF Talk Takes A Back Seat To Tariffs April 22, 2025
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- Boeing reports mixed results of latest employee survey, but middle management and officers remain key obstacles April 22, 2025
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- Bjorn’s Corner: Air Transport’s route to 2050. Part 18. April 18, 2025
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.
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.
Bjorn’s Corner: The challenges of hydrogen. Part 27. Fuel cell APU gains
By Bjorn Fehrm
March 5, 2021, ©. Leeham News: We have discussed different auxiliary power generation principles for a hydrogen aircraft over the last weeks. We found a fuel cell auxiliary power system has many attractions, one being the possibility of making an elegant more-electric aircraft system architecture.
With or without such an architecture, the fuel cell alternative will save hydrogen consumption and cost compared to a hydrogen-converted APU alternative. What’s the value of the saving?
Figure 1. The Ballard/Audi FCgen-HPS fuel cell stack for cars and other mobility applications. Source: Ballard Power Systems Inc.
Bjorn’s Corner: The challenges of hydrogen. Part 26. Auxiliary power
February 26, 2021, ©. Leeham News: Last week we discussed auxiliary power generation for a hydrogen aircraft and found that a fuel cell system had many attractions.
However, it’s more challenging to develop than a hydrogen-converted APU, and we were asked to work through this case as well.
Figure 1. The principal parts of a single-aisle APU. Source: United Technologies.
Bjorn’s Corner: The challenges of hydrogen. Part 25. Auxiliary power
By Bjorn Fehrm
February 19, 2021, ©. Leeham News: Last week we discussed hydrogen aircraft propulsion and found a shaft power producing gas turbine was considerably more weight-efficient than a fuel cell powering an electric motor. Both had the same 55% shaft power efficiency.
Will a gas turbine APU burning H2 be the best choice for auxiliary power as well?
Figure 1. The Honeywell 131-9 APU for the Airbus A320. Source: Honeywell.
Bjorn’s Corner: The challenges of hydrogen. Part 24. Propulsion choice
By Bjorn Fehrm
February 12, 2021, ©. Leeham News: After covering the basics of fuel cells last week in our hydrogen airliner series, we now look at what type of system to choose for aircraft propulsion and onboard systems power.
We analyze the propulsion side this week.
Figure 1. A SAFRAN concept for a low emission airliner from its Clean Sky 2 presentation. Source: SAFRAN.
Bjorn’s Corner: The challenges of hydrogen. Part 23. Hydrogen fuel cells
By Bjorn Fehrm
February 5, 2021, ©. Leeham News: Last week, we started the discussion around fuel cells as a source of electric energy in airliners. We went through the principle and asked some vital questions.
Now we look at different types of fuel cells and for what applications these are suited.
Figure 1. The principle of a hydrogen fuel cell. Source: Airbus.
Bjorn’s Corner: The challenges of hydrogen. Part 22. Hydrogen fuel cells
By Bjorn Fehrm
January 29, 2021, ©. Leeham News: Over the last weeks, we looked at Center of Gravity (CG) problems with rear fuselage liquid hydrogen tanks as used in Airbus’ ZEROe turbofan airliner concept. We can conclude that the CG shift is manageable for a short-range aircraft (range below 2,000nm).
Now we spend the next Corners diving into hydrogen fuel cell technology and how it can benefit a hydrogen-fueled airliner.
Figure 1, The principle of a hydrogen fuel cell. Source: Airbus.
Bjorn’s Corner: The challenges of hydrogen. Part 21. Hydrogen airliner weight shift
By Bjorn Fehrm
January 22, 2021, ©. Leeham News: In last week’s Corner, we looked at how the hydrogen consumed in the rear fuselage tanks changes the airliner’s Center of Gravity (CG).
Now we discuss how this change of Center of Gravity, limiting the aircraft’s load flexibility, can be mitigated with different concepts.
Figure 1. Airbus ZEROe turbofan airliner. Source: Airbus.
Bjorn’s Corner: The challenges of hydrogen. Part 20. Hydrogen airliner weight shift
By Bjorn Fehrm
January 15, 2021, ©. Leeham News: In last week’s Corner, we looked at how hydrogen consumed in the rear fuselage tanks of Airbus’ ZEROe concept affect the airliner’s efficiency.
Now we look at other aspects of the rear placement of the tanks.
Figure 1. Airbus ZEROe turbofan airliner. Source: Airbus.