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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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.

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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.

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