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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The reality behind the eVTOL industry’s hyperbole, Part 7.

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By Bjorn Fehrm

August 24, 2023, © Leeham News: We have looked at the promises the VTOL industry made in their Investor prospects and what the reality is as the VTOLs come closer to Certification and production.

We started by using Joby and Archer as examples; now, we wrap the series by looking at some other top VTOL OEMs and how their claims have changed as the projects come closer to reality.

Figure 1. The Lilium jet VTOL. Source: Lilium.

Summary:
  • Joby Aviation and Archer are not alone in backpedaling on promised performance as certification nears; other OEMs that are investor-financed have the same problem.
  • In summary, the VTOLs in the first generation can only fly short-range missions. Longer flights run into energy reserve and cost problems.

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The reality behind the eVTOL industry’s hyperbole, Part 6.

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By Bjorn Fehrm

August 17, 2023, © Leeham News: We look at the promises that the VTOL industry has made in their Investor prospects and what the reality is as they come closer to Certification and production.

We used our Aircraft Performance and Cost model to understand the data for the typical missions for the Joby S4 and Archer Midnight VTOLs and how the economics pans out for these missions. We now look at the results and compare them to what’s been projected from the OEMs.

Figure 1. The Joby S4 VTOL. Source: Leeham Co.

Summary:
  • We found the VTOL OEM’s economics for the typical 10-minute shuttle flights optimistic.
  • When we go back and look at investor deck projections, the cost comparison to helicopter costs were totally off the mark. When we correct this the VTOL is more expensive to operate then an equivalent helicopter.

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The reality behind the eVTOL industry’s hyperbole, Part 5.

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By Bjorn Fehrm

August 10, 2023, © Leeham News: We look at the promises that the VTOL industry has made in their Investor prospects and what the reality is as they come closer to Certification and production.

After looking at claims of range and utility, we now look at the operating economics. We go through the different cost factors for a VTOL, add them up, and compare them with the industries’ projections.

Figure 1. The Archer Aviation Midnight VTOL mockup at the Paris Air show. Source: Leeham Co.

Summary:

·         The VTOL OEMs state their economics for 10-minute shuttle flights while claiming the VTOL can also fly flights four times longer.

·         Yes, the VTOLs can indeed fly these longer flights, but then the economics fall apart.

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The reality behind the eVTOL industry’s hyperbole, Part 4.

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By Bjorn Fehrm

August 3, 2023, © Leeham News: We look at the promises that the VTOL industry has made in their Investor prospects and the reality as they come closer to Certification and Production.

After looking at claims of range and utility, we now look at the operating economics. To do that, we need to predict the net sales price of these machines. We use our Aircraft Performance and Cost Model (APCM) to predict the production cost over time and, thus, the needed net sale price of the VTOLs.

Figure 1. The Archer Aviation Midnight VTOL mockup at the Paris Air show. Source: Leeham Co.

Summary:
  • The VTOLs are big; the Archer Midnight is the size of a nine-seater commuter aircraft (Figure 1). Aircraft costs are related to size and weight.
  • VTOLs use aeronautical production methods and supply chains for parts and systems. The production costs are, therefore, predictable.

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The reality behind the eVTOL industry’s hyperbole, Part 3.

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By Bjorn Fehrm

July 27, 2023, © Leeham News: We look at the promises that the VTOL industry has made in their Investor prospects and what the reality is as they come closer to Certification and present their production-level prototypes. We also analyze whether these capabilities will be the final level.

Today we go through the trickiest part of any electric aircraft or eVTOL, the batteries. They are large, very heavy, and the most difficult part to certify on the aircraft, as the battery is dangerous if not designed, produced, and managed correctly.

Figure 1. The Joby Aviation S4 production prototype. Source: Joby Aviation.

Summary:
  • The battery system of an eVTOL sets restrictions on the operational usefulness of the category.
  • The everyday operational utility of VTOLs is far from the industries’ claims.

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The reality behind the eVTOL industry’s hyperbole, Part 2.

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By Bjorn Fehrm

July 20, 2023, © Leeham News: We look at the promises that VTOL OEMs made in their Investor prospects and the scale-down in capabilities as Certification comes closer. We also analyze whether the reduced capabilities will be the final cuts.

In the end, it’s about how operationally useful real-world eVTOL will be and what mission they do better or cheaper than helicopters. It will decide whether the category will have a breakthrough or not.

Figure 1. The Joby Aviation S4 production prototype. Source: Joby Aviation.

Summary:
  • The Investor’s presentations from eVTOL OEMs are full of “up to” for speeds and feeds.
  • When we use our aircraft and eVTOL performance model, the reality is well short of the claims.

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The Small Airliner Problem, Part 10. Cash costs for a battery-based airliner

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By Bjorn Fehrm

July 6, 2023, © Leeham News: In our series on costs factors that make up Cash Operating Cost for a battery-based airliner with range extenders, we now add Crew costs and Airport/Airway fees.

We then have all the components of the Cash Operating Cost (COC) for the ES-30 and can compare it to a normal propulsion 30-seat turboprop.

Figure 1. The Heart Aerospace ES-30 hybrid 30-seat airliner. Source: Heart Aerospace.

Summary:
  • The high operating weight and slow speed of a battery airliner increase the Airport/Airway fees and Crew costs for the ES-30.
  • In summary, only one Cash cost remains competitive, and the COC total exceeds the cost of a 30-seater turboprop.

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The Small Airliner Problem, Part 9. Maintenance costs for battery airliners with range extenders

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By Bjorn Fehrm

June 29, 2023, © Leeham News: In our series on fundamental costs factors that make up Cash Operating Cost, COC (Fuel, Maintenance, Airway/Airport fees, Crew costs) for new Green airliners, we have analyzed the energy costs and now move on to the maintenance costs.

For a battery-based airliner with range extenders, it’s a complex mix of battery and gas turbine costs.

Figure 1. The Heart Aerospace ES-30 hybrid 30-seat airliner. Source: Heart Aerospace.

Summary:
  • The maintenance costs for a battery-based airliner are high. It’s the batteries that cost, not the electric motors.
  • Adding range extenders complicates the propulsion system and adds further costs.

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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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