Bjorn’s Corner: New aircraft technologies. Part 12P. Airframe efficiency improvement

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By Bjorn Fehrm

May 12, 2023, ©. Leeham News: This is a complementary article to Part 12. Airframe efficiency improvement. It discusses in detail the next-generation airframe improvements we can expect. We start with detailing the size of airframe inefficiency for today’s airframes, then look at the areas we can improve.

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The Small Airliner Problem, Part 4

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By Bjorn Fehrm

May 11, 2023, © Leeham News: In our series about the viability of the business plans for small airliners (nine to 50 seats), we have covered how energy/fuel consumption and maintenance scales with the size of the airliner.

The cost factor we examine today is the cost of using the airport and airways infrastructure. Airlines pay for landing plus parking at airports and for using their passenger facilities. The airlines also pay for using the Air Traffic Control (ATC) infrastructure when flying the routes.

Each airport and national airway system have their own fee structures. We check how these scale with aircraft size.

Figure 1. The TECNAM P2021 piston prop airliner is also offered in an electric version called P-Volt. Source: TECNAM.

Summary:
  • Airway fees scale differently per transported passenger to the airport fees.
  • Overall, airport and airway fees are not proportional to carried passengers on a route.

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Bjorn’s Corner: New aircraft technologies. Part 11. Airframe.

By Bjorn Fehrm

May 5, 2023, ©. Leeham News: In our series on the different technologies available when developing next-generation airliners, we have covered the fuselage configuration and engine options.

Now we turn to airframe technologies. We will look at different airframe architectures, their advantages, and disadvantages. To support the discussion, we will model the different variants in our Airliner Performance and Cost model to understand their characteristics.

Figure 1. The Boeing truss-braced wing is a candidate for the next Heart of the Market airliner. Source: Boeing.

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The Small Airliner Problem, Part 3

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By Bjorn Fehrm

May 4, 2023, © Leeham News: In our series about the viability of the business plans for small airliners (nine to 50 seats), we have covered how energy and fuel consumption scales with the size of the airliner.

The cost factor we examine today is the maintenance cost for keeping an airliner fit for purpose and safe.

We use the Leeham aircraft performance and cost model to get the data for the maintenance costs for airliners going from nine to 200 seats.

Figure 1. The Cessna Sky Courier is a new 19-seat small airliner with conventional propulsion. Source: Textron Aviation.

Summary:
  • The maintenance costs of an airliner scale differently from the energy and fuel consumption we studied last week.
  • We discuss the scaling metrics for the airframe maintenance costs and how these differ from what drives engine maintenance costs.

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Bjorn’s Corner: New aircraft technologies. Part 10. Engine choice

By Bjorn Fehrm.

April 28, 2023, ©. Leeham News: This is a summary of the article New aircraft technologies. Part 10P. Engine choice. The article discusses the engine architecture choices that must be made when developing the next-generation airliners.

Figure 1. The Pratt & Whitney high bypass geared turbofan technologies. Source: Pratt & Whitney.

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Bjorn’s Corner: New aircraft technologies. Part 10P. The engine choice

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By Bjorn Fehrm

April 28, 2023, ©. Leeham News: This is a complementary article to Part 10. The engine choice. It discusses in detail the next-generation engines for the Heart of the Market airliners that today are called the single-aisle segment. What will be the alternatives and final engine choice? Will hydrogen-fueled engines play a role?

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Bjorn’s Corner: New aircraft technologies. Part 9P. Engine core advances

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By Bjorn Fehrm

April 21, 2023, ©. Leeham News: This is a complementary article to Part 9. Engine core advances. It discusses in detail the next-generation propulsion system cores and what efficiency improvements to expect from different technological advancements.

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The Small Airliner Problem

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By Bjorn Fehrm

April 20, 2023, © Leeham News: New Sustainable aircraft projects, for economical reasons, target small airliner types as first projects and then, after proving the concept, to move up in size. The number of 9-seat, 19-seat, and 30- to 50-seat upstarts announced over the last years must be in the hundreds.

They all claim major advances in environmentally friendly propulsion and that their first aircraft have viable business models. In their business plans, there are elaborate explanations why local air services will flourish through the introduction of small, environmentally friendly aircraft.

The reality is another. The airliner size, where more than 100 aircraft per year are delivered, is 200 seats increasing, and sales below 50 seats have slowed to a trickle. ATRs, the leading supplier of airliners below 70 seats, delivered five 50-seater turboprops during 2022 out of a total of 29. The 50-seater model stayed at around 10% of deliveries between 2014 to 2019 before COVID, when total production was 70 to 80 turboprops per year.

There are economic reasons for these low numbers, and these are not changing for the better. We will explore these reasons using our airliner Performance and Cost model in a series of articles, where we compare operational costs for 9-, 19- and 50-seaters to the larger aircraft.

Figure 1. The latest small airliner project from Maeve Aerospace. A 50-seater battery-based electric aircraft. Source: Maeve Aerospace.

Summary:
  • We show the cost factors and their proportions for different airliner sizes.
  • Then we look at how these factors scale with aircraft size.

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The production cost trap for eVTOL upstarts

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By Bjorn Fehrm

April 13, 2023, © Leeham News: Last week, we gave the example of a new propulsion principle 30-seat airliner as a project that would face the liquidity strain of initial production costs. We continue today with a look at the leading eVTOL projects, where development costs are passing $1bn and growing.

What will be the cash burn before these projects generate positive cash flow from serial production sales and services? We use our production cost model to analyze the situation.

Figure 1. Our generic eVTOL uses an early rendering of the Vertical VX4 as an illustration. Source: Vertical Aerospace.

Summary:
  • VTOL projects promise early payback of invested capital.
  • Our production cost model says otherwise.

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Bjorn’s Corner: New aircraft technologies. Part 7. Propulsion

By Bjorn Fehrm

April 7, 2023, ©. Leeham News: This is a summary of the article New aircraft technologies. Part 7P. Propulsion. The article discusses how developments in the next-generation airliner propulsion system will be the second most important area for improved efficiency and lower emissions after we have decided on the fuselage type.

Figure 1. The CFM LEAP engine gained 15% efficiency compared to the engine it replaced, the CFM56. Source: CFM.

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