Bjorn’s Corner: Air Transport’s route to 2050. Part 7.

By Bjorn Fehrm

January 31, 2025, ©. Leeham News: We do a Corner series about the state of developments to replace or improve hydrocarbon propulsion concepts for Air Transport. We try to understand why the development has been slow.

We have covered the progress of battery-based aircraft and hybrids, both serial and parallel hybrids. A couple of mild hybrids have a larger chance of success than the ones we described. We will look into these and then start looking at different hydrogen-fueled alternatives.

Figure 1. The LEAP-1A with auxiliary gearbox. Source: Safran Transmissions.

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Bjorn’s Corner: Air Transport’s route to 2050. Part 6.

Bjorn Fehrm

January 24, 2025, ©. Leeham News: We do a Corner series about the state of developments to replace or improve hydrocarbon propulsion concepts for Air Transport. We try to understand why the development has been slow.

We have covered why the progress of battery-based aircraft is slow and also described what to expect at the end of this decade and the beginning of next.

Now, we look at hybrids, an inherently more complex design. Upstarts are changing to hybrids after realizing that battery-only aircraft will not have useful range this side of 2030.

Figure 1. The Heart Aerospace ES-30 has passed the phases in the article. Source: Heart Aerospace.

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Bjorn’s Corner: Air Transport’s route to 2050. Part 5.

By Bjorn Fehrm

January 17, 2025, ©. Leeham News: We do a Corner series about the state of developments to replace or improve hydrocarbon propulsion concepts for Air Transport. We try to understand why the development has been slow.

We have covered why the technical progress of battery-based aircraft has been slow. Now we look at what type of missions it can do this decade and beyond and why the limitations.

Figure 1. The Diamond eDA40 electric trainer. Source: Diamond. Read more

Bjorn’s Corner: Air Transport’s route to 2050. Part 4.

By Bjorn Fehrm

January 10, 2025, ©. Leeham News: We do a Corner series about the state of developments to replace or improve hydrocarbon propulsion concepts for Air Transport. We try to understand why the development has been slow.

We listed the different projects in the second Corner of the series that have come as far as flying a functional model or prototype. In Part 3, we went through some of the causes of the slow growth. It was a mix of inexperienced startup managments, all wanting to be the new Elon Musk but lacking elementary knowledge in the aeronautical field, to what is the real hard part of an alternative propulsion concept.

Many startups developed new electric motors for eAirplane or eVTOL use, a relatively straightforward development when the real hard part is the batteries. We described how batteries differ significantly from fuel as an energy source in Part 3.

Now, we add a market aspect that is poorly understood by most players.

Figure 1. The Pipistrel Velis Electro trainer. Source: Pipistrel.

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Bjorn’s Corner: Air Transport’s route to 2050. Part 3

By Bjorn Fehrm

November 1, 2024, ©. Leeham News: We do a Corner series about the state of developments to replace or improve hydrocarbon propulsion concepts for Air Transport. We will find that development has been very slow.

Last week, we listed the different projects that have come as far as flying a functional model or prototype, as we need this filter to reduce the hundreds of projects that have declared they want to develop such an aircraft type. We can see that we have only a certified two-seat trainer, and one project has a prototype that has started certification, the CX300 six-seater in Figure 1.

Why is the progress so slow?

Figure 1. The Alia CX300 six-seater started certification in 2023. Source: Beta Technologies.

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Bjorn’s Corner: Air Transport’s route to 2050. Part 2.

October 24, 2024, ©. Leeham News: We do a Corner series about the state of developments to replace or improve hydrocarbon propulsion concepts for Air Transport. We will find that development has been very slow.

We don’t have, and will not have, a certified and produced aircraft that can transport passengers using anything but classical propulsion concepts this side of 2028 and probably 2030 if we put the bar above five passengers.

This is 14 years after the flight of the Airbus E-Fan in 2014, which started a multitude of studies and projects to explore new, more environmentally friendly ways to propel aircraft.

Figure 1. The Airbus E-fan flying at the 2014 Farnborough Air Show. Source: Wikipedia.

Why is the progress so slow? Normal aircraft development takes seven to a maximum of nine years?

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Heart Aerospace’s revised ES-30, Part 3. UPDATED

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By Bjorn Fehrm

October 24, 2024, © Leeham News: We analyze Heart Aerospace’s latest evolution of the hybrid ES-30. The latest version, presented in spring 2024, is a parallel hybrid, putting gas turbine turboprop engines outside the electric motor engines.

After examining what such a parallel hybrid system means for aircraft dimensions and masses, we now fly the aircraft on a typical US short-haul route through our Aircraft Performance and Cost Model (APCM) to assess its operational performance.

Does the ES-30 make operational sense for an airline that needs a short-haul feeder?

Summary:
  • The parallel hybrid architecture gives the ES-30 certain operational flexibility to fly routes over 100nm, making it possible to replace present 30 seaters on such short routes.
  • However, the operational costs are considerably higher than today’s 30-seaters. As always, the problem is the battery costs.
  • UPDATE: Heart Aerospace contacted us after the article was published. The article has been complemented with their information.

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Bjorn’s Corner: Air Transport’s route to 2050. Part 1.

By Bjorn Fehrm

October 18, 2024, ©. Leeham News: In Corners over the last years, we have covered new airliner technology and engine developments that would apply to the next-generation airliners in the largest segment of the market, the single-aisle segment, or as we like to call it, the Heart of the Market segment, as it’s not sure it will be a single-aisle aircraft.

The series has assumed this generation will be hydrocarbon-fueled gas turbine-propelled airplanes. Therefore, it has not covered the current state of alternatives to gas turbine-based hydrocarbon propulsion.

We will cover this now. We are now 10 years into the discussions and work of reducing Air Transport’s reliance on hydrocarbon fuels, which started in earnest when Airbus flew the E-Fan battery-electric aircraft at the Farnborough Air Show in 2014, Figure 1.

How are we doing?

Figure 1. Airbus E-Fan at Farnborough Air Show 2014. Source: Wikipedia.

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Heart Aerospace’s revised ES-30

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By Bjorn Fehrm

September 26, 2024, © Leeham News: Heart Aerospace has revised its environmentally friendly aircraft for the third time. The variants started in September 2020, when Heart presented an all-electric, battery-based 19-seat airliner that should test fly by now and be available in 2026, Figure 1, top aircraft.

Two years later, in September 2022, it all changed. The aircraft was changed to a 30-seater with a serial hybrid propulsion system using turboextenders to increase the operational range, Figure 1, aircraft two.

After another 20 months, the configuration changed again to the third iteration in Figure 1, which will fly in prototype in 2026 and be available to airlines in 2029.

In an article series, we explain the reasons for these changes and analyze whether the changes in the aircraft have increased the likelihood of the ES-30 entering the market in 2029.

Figure 1. The Heart Aerospace regional airliner series. Top, the ES-19, then the ES-30, and finally, the revised ES-30. Source: Heart Aerospace.

Summary:
  • Heart Aerospace has followed the typical trajectory for an electric aircraft startup.
  • It begins with an all-electric, battery-based airliner that will change regional flying.
  • Gradually, reality sets in, and all-battery architecture becomes a serial hybrid and, finally, a parallel hybrid.
  • We analyze if the evolution trail increases the chances we will fly on Heart Aerospace airliners come 2030.

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Bjorn’s Corner: New engine development. Part 22. High Turbine technologies.

By Bjorn Fehrm

August 30, 2024, ©. Leeham News: We do an article series about engine development and why it has longer timelines than airframe development. It also carries larger risks of product maturity problems when it enters service than the airframe of an airliner.

We reached the turbine part on our way through the engine, where we last looked at high-pressure turbine temperatures. It’s the most stressed part of the engine and, in most cases, decides its durability. To understand why, we look closer at turbine technologies.

Figure 1. Our example engine, the LEAP-1A, is in cross-section with booster to compressor bleed valve area marked with a red circle. Source: CFM.

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