Bjorn’s Corner: New engine development. Part 10. Airframe integration

By Bjorn Fehrm

May 24, 2024, ©. Leeham News: We do an article series about engine development. The aim is to understand why engine development now has longer timelines than airframe development and carries larger risks of product maturity problems.

To understand why engine development has become a challenging task, we need to understand engine fundamentals and the technologies used for these fundamentals.

In the last Corner, we looked at the nacelles used for a turbofan engine and for an open-rotor engine. Now, we go one step further and look at the integration of modern engines on an airliner.

Figure 1. Boeing 737NG (left) and MAX (right) nacelles compared. Source: Leeham Graphic from Boeing 737 images.

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Airbus’ A350-1000 or Boeing’s 777-8? Part 1

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By Bjorn Fehrm

May 9, 2024, © Leeham News: We are doing an article series comparing the capabilities of the Airbus A350-1000 and the Boeing 777X series. We started with the 777-9, the larger model. Now, we continue with the shorter 777-8, an aircraft closer in size to the A350-1000.

The 777-8 was originally launched in a shorter version together with the 777-9. Then, it went very quiet around the 777-8, with some analysts speculating that the passenger version would not be done. The 777X freighter, the 777-8F, was launched in January 2022. It became a bit longer than the 777-8. This now forms the final definition of the 777-8.

Summary:

  • The comparison of the A350-1000 and the 777-8 is comparing the longer-narrower versus the shorter-wider.
  • Which is the best? We use Leeham’s Aircraft Performance and Cost Model (APCM) to find out.

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A350-1000 or 777-9? Part 4

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By Bjorn Fehrm

May 2, 2024, © Leeham News: We are doing an article series comparing the capabilities of the Airbus A350-1000 and the Boeing 777-9. We looked at the development history of the aircraft and then their capability and fuel economics.

We could see that the 777-9 is trailing the A350-1000 in payload range, partly because we compare the base version of the 777-9 with a further developed A350-1000. Now, we investigate what the 777-9 performance would be should we include a typical future development of the Maximum TakeOff Weight (MTOW).

Summary:
  • The A350-1000 has a clear payload-range advantage over the standard 777-9.
  • With an in-service Maximum TakeOff Weight (MTOW) development like the A350-1000, the difference is reduced.

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A350-1000 or 777-9? Part 3

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By Bjorn Fehrm

April 25, 2024, © Leeham News: We are doing an article series comparing the capabilities of the Airbus A350-1000 and the Boeing 777-9. We looked at the development history of the aircraft and compared their size and payload capacity.

Now, we use our Aircraft Performance and Cost Model (APCM) to fly the aircraft on a typical route and compare their performance. We also look at their stage of development and the potential for future upgrades inherent in the design.

Summary:
  • The A350-1000 has got its Maximum TakeOff Weight (MTOW) increased four times since entry into service.
  • The latest MTOW hike to 322t gives the A350 a clear payload-range advantage over the 777-9. Any increase in the 777-9’s MTOW will have to come after type certification.

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Airbus’ A350-1000 or Boeing’s 777-9?

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By Bjorn Fehrm

April 4, 2024, © Leeham News: Korean Air confirmed an order for 33 Airbus A350 in the week, 27 of which are the larger A350-1000. The order is significant on two accounts:

First, 27 A350-1000 and only 6 A350-900, where analysts have for years asked why the -1000 isn’t selling.

Secondly, for a carrier that has a rather 50-50 fleet of Airbus and Boeing planes, its large widebody was the Boeing 777-300ER, whereof it has 27 out of 37 Boeing 777 in total. Korean Air now chooses the A350-1000 to replace the 777-300ER. Why not the 777-9?

Was this a question of availability (the 777-9 should have been delivered in 2020 but has had several delays; the present plan says 2025), or was there a technical-economic reason for Korean Air’s decision? We examine the characteristics of the two planes to find the answers.

Summary:
  • The Boeing 777-300ER was an exceptionally successful stretch of the original 777-200. The 777-9 is the sequel to the 777-300ER.
  • The market did not like the original A350-1000. Therefore, the present -1000 is a reconfigured aircraft compared to the original variant.

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Bjorn’s Corner: New aircraft technologies. Part 51. Wrap up

By Bjorn Fehrm

March 22, 2024, ©. Leeham News: Last week we did the first part of the Wrap-up of our 50 article series about the New Aircraft Technologies that can be used when replacing our present single-aisle airliners.

Now, we summarize the last 25 articles in the series, which covered how to develop, produce, and support a new airliner.

Figure 1. The Program Plan for a new airliner. Source: Leeham Co.

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Bjorn’s Corner: New aircraft technologies. Part 50. Wrap up.

By Bjorn Fehrm

March 15, 2024, ©. Leeham News: We started the series a year ago about the New Aircraft Technologies that can be used when replacing our present single-aisle airliners.

We have covered a lot, including the typical development phases, from initial studies to preparing for the aircraft’s in-service phase.

Let’s make a resume of what we have discussed.

Figure 1. Boeing’s Truss Braced Wing X-66A demonstrator based on the MD-90. Source: Boeing.

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Bjorn’ s Corner: New aircraft technologies. Part 49. Engine Maintenance

By Bjorn Fehrm

March 8, 2024, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering the Design and Production, we now look at the Operational phase of a new airliner family.

For the operational phase, the airplane must pass scrutiny for Continued Airworthiness. The biggest item in a regulator’s Instructions for Continued Airworthiness is the required Maintenance program to keep an airliner airworthy. We discussed airframe maintenance in the last article. Now, we look at engine maintenance.

Figure 1. The CFM56-7 engine for the Boeing 737NG. Source: CFM.

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Bjorn’ s Corner: New aircraft technologies. Part 47. MSG-3 Maintenance

By Bjorn Fehrm

February 2, 2024, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering the Design and Production, we now look at the Operational phase of a new airliner family.

For the operational phase, the airplane must pass scrutiny for Continued Airworthiness. The biggest item in a regulator’s Instructions for Continued Airworthiness is the required Maintenance program to keep an airliner airworthy. We started last week with how maintenance went from ad-hoc to a Hard Timed maintenance program in the late 1950s and early 1960s.

Figure 1. The maintenance manual for the Boeing 747. Source: Boeing.

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Bjorn’ s Corner: New aircraft technologies. Part 46. Maintenance Program

By Bjorn Fehrm

January 19, 2024, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering the Design and Production, we now look at the Operational phase of a new airliner family.

For the operational phase, the airplane must pass scrutiny for Continued Airworthiness. Today, we discuss the biggest item in a regulator’s Instructions for Continued Airworthiness: the required Maintenance to keep an airliner airworthy.

Figure 1. A typical maintenance program for an airliner. Source: ATR.

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